US2442434A - Dermatome - Google Patents
Dermatome Download PDFInfo
- Publication number
- US2442434A US2442434A US618523A US61852345A US2442434A US 2442434 A US2442434 A US 2442434A US 618523 A US618523 A US 618523A US 61852345 A US61852345 A US 61852345A US 2442434 A US2442434 A US 2442434A
- Authority
- US
- United States
- Prior art keywords
- graft
- dermatome
- convex
- transfer member
- shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005520 cutting process Methods 0.000 description 40
- 239000000853 adhesive Substances 0.000 description 20
- 230000001070 adhesive effect Effects 0.000 description 20
- 230000007246 mechanism Effects 0.000 description 17
- 210000003811 finger Anatomy 0.000 description 11
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- 210000003813 thumb Anatomy 0.000 description 6
- 239000004568 cement Substances 0.000 description 3
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- 229910000760 Hardened steel Inorganic materials 0.000 description 2
- 239000012790 adhesive layer Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
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- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910001369 Brass Inorganic materials 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 239000002390 adhesive tape Substances 0.000 description 1
- 210000000577 adipose tissue Anatomy 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
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- 229910001220 stainless steel Inorganic materials 0.000 description 1
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Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/32—Surgical cutting instruments
- A61B17/322—Skin grafting apparatus
Definitions
- This invention relates to surgery, more particularly to skin grafting, and has for an object to provide an improved dermatome for cutting a skin graft.
- Another object of the invention is to provide, in a dermatome of the type comprising a body member having a convex working face and a knife supported by the body member for cutting movement parallel to said convex face and at a predetermined distance therefrom, improved means for adjusting the spacing of the knife with respect to the convex working face.
- another object of the invention is to provide, in a dermatome, means for positively securing a graft-receiving member against a convex working face, with the contact pressure between the member and the face uniform at all points therebetween.
- a further object of the invention is to provide a dermatome having means for mechanically securing against its WOrking face, a graft-receiving member of flexible material.
- Yet another object of the invention is to provide a dermatome having means for mechanically securing to its working face, a graft-receiving member of flexible material, together with means for drawing said member taut against said working face.
- Another object of the invention is to provide a dermatome constructed of a combination of such materials as will result in uniform expansion and contraction of all parts thereof when the dermatome is sterilized at high temperatures.
- Fig. 1 is a front elevational view, partially in section, of a dermatome embodying features of the present invention
- Fig. 2 is a vertical sectional view, taken along the line II1I of Fig. 1, looking in the direc tion indicated by the arrows;
- Fig. 3 is a plan view of a graft-receiving or graft-transfer member, adapted for use with the dermatome of the present invention, portions thereof being broken away at one corner to more clearly illustrate the laminated construction;
- Fig. 4 is a view similar to Fig. 3, showing a modified graft-receiving member
- Fig. 5 is a fragmentary sectional view of the injured area of a patients body, showing a skin graft retained thereon;
- Fig. 6 is a front elevational view of an improved dermat-ome, constructed in accordance with the present invention.
- Fig. '7 is a transverse sectional view of the dermatome shown in Fig. 6, and taken along the 3 line VIVI of Fig. 12, looking in the direction indicated by the arrows:
- Fig. 8 is an enlarged sectional view, taken along the line VIII-VIII of Fig. 'I, looking in the direction indicated by the arrows;
- Fig. 9 is a plan view of the blade-supporting bar
- Fig. 10 is a plan view of the cutting blade
- Fig. 11 is a sectional view taken along the line XI-lfl of Fig. 8, looking in the direction indicated by the arrows;
- Fig. 12 is a plan view of the dermatome shown in Figs. 1 and 2;
- Fig. 13 is a view of the left end of the dermatone shown in Fig. 6;
- Fig. 14 is an enlarged fragmentary plan view of the structure shown at the lower right corner of Fig. 12, with the latch moved to releasing position.
- Fig. 15 is an enlarged fragmentary view of the right-hand end of Fig. 13, with the clamping bar in released position;
- Fig. 16 is a plan view of one of the shims
- Fig. 17 is an enlarged fragmentary view of the left-hand end of Fig. 13;
- Fig. 18 is a fragmentary sectional view, taken along the line XVIII-XVIII of Fig. 13, looking in the direction indicated by the arrows;
- Fig. 19 is an enlarged fragmentar sectional view, taken along the line XIX-XIX of Fig. 12, looking in the direction indicated by the arrows, and showing the graft-transfer member in position before tightening;
- Fig. 20 is a view similar to Fig. 17, but showing the graft-transfer member in final tightened position.
- Fig. 21 is a plan view of the wrench or tool used to adjust the ratchet and the cam;
- Fig. 22 is a transverse sectional view of a modified form of dermatone.
- Fig. 23 is a side elevational view, taken along the line 2QIII-XXIII of Fig. 22, looking in the direction indicated by the arrows, the shaft and associated post structure being omitted.
- the reference character ill indicates, in its entirety, a dermatone comprising a body portion II in the form of a semi-cylindrical drum I made of a spaced pair of semi-cylindrical side walls l2, joined by a curved end wall 13 having an outer convex working face 14.
- the side walls 12 carry a bearing i6 bridging the space between the side walls and positioned so that its longitudinal axis coincides with the axis of generation of the convex working face l4.
- a shaft I1 is journaled in the bearing [6 for both rotary and reciprocatory movement relative to the body member, and carries at its terminal portions 9.
- pair of posts Is which extend radially relative to the convex working face l4, in parallel, spaced-apart relation, with the spacing therebetween considerably greater than the width of the body member or drum l i, to provide for reciprocatory movement of the shaft H and posts l8 relative to said body member.
- the posts may be retained on the" shaft terminal portions by a pair of knurled finger nuts l9, although, preferably, a handle or finger piece 2
- a blade-supporting bar 22 is carried by the outer ends 23 of the posts, and is provided with a pair of lugs 24, slidably received in bores formed in the post ends 23.
- a knife 21 is adapted to be supported on the bar 22, with its cutting edge 28 in parallel relation to the convex surface H of the drum.
- , rotatable in bores 32 of the posts, have threaded connections, at their inner ends 33, with threaded bores in the lugs 24.
- the outer ends of the rods 3! carry knurled finger pieces 34, by which the rods may be rotated to move the lugs longitudinally of the bores 25 in which they are positioned, inward movement of the lugs serving to draw the bar 22 towards the ends of the posts to securely clamp the knife 2'! thereagainst.
- Adjustment of the spacing of the knife with respect to the convex working face M is obtained by inserting between the knife and the post ends 23, shims 36 of the desired thickness.
- the present invention provides a dermatome adapted to make use of a skin graft-receiving or graft-transfer member 40, in the form of a flexible sheet.
- the graft-transfer member 40 comprises an intermediate strip of fabric 4
- a layer or coating 43 of rubber On the upper face of the fabric 4! is permanently secured a layer or coating 43 of rubber, whose surface which is away from the fabric is of an adhesive character. To protect the adhesive surface, the latter is covered with a strip of protective material 44, preferably of cloth which has been starched, varnished or otherwise processed.
- the graft-transfer member 40 is of a width slightly less than the distance between the body member side walls I2, and of a length materially greater than the developed length of the convex working face l4 of the body member, the excess length constituting securing portions B, at each end of the strip, and the remaining intermediate section constituting a skin-contacting portion A,
- the graft-transfer member 40 is applied to the body member of the dermatome, with the smooth inner surface of the rubber layer 42 against the convex working face of the body member, the intermediate skin-contacting portion A terminating adjacent the ends of the convex face.
- the securing portions B of the member 40 are drawn over the ends of the convex wall [3 and the protective layer 44 may first be removed therefrom, although this is not generally necessary.
- the protective layer 44 is provided with a break at the line where the portion A terminates and the portion B commences, as at 46 in Fig. 3. If desired, the protective layer may be merely weakened by a cut or by a row of serrations or perforations, indicated at 41 in Fig. 4.
- the breaks 46, or cuts or perforations 41 provide the give in the layer 44 -which is necessary to permit the strip 4
- the dermatome is provided with means for mechanically securing the graft-transfer member there-
- the dermatome side walls l2 are provided, adjacent one end of the curved wall I3, with a pair of slots 50, which are inclined towards said one end of the curved wall, relative to the inner surface of that wall.
- a knurled bar or roller 5! has its terminal portions mounted in the slots 50, for free rolling or sliding movement therein.
- the adjacent securing portion B of the grafttransfer member is positioned in the space between the bar 5! and the inner surface of the curved wall i3, any pull on the securing portion B in an upward direction, as viewed in Fig. 2, resulting in wedging of the bar 5
- the securing portion B at the opposite end of the graft-transfer member may be held by a quick-release latch or dog 52, pivoted at 53 to the side walls 12, and having a grip 54 and handle 56, as well as a stop 5?.
- the entire latch or dog may be of well known construction, such as is frequently used in buckles.
- a tightening rod 58 pivotally mounted in opposed openings in the side walls It, and formed with a cam surface eccentric relative to its axis of rotation.
- One end of the rod 58 may extend beyond the corresponding side wall I2, and carry a knurled finger piece 59, by which the rod may be rotated to cause the cam surface thereof to raise the graft-transfer member where it passes thereover, to draw the member taut.
- the inner convex-face-engaging surface of the graft-transfer member is made smooth and dry, so that it may slip easily on said convex face.
- the protective layer M is left on the intermediate skin-contacting portion A until such time as the graft is to be cut, when the layer M is removed and the graft cut in a manner obvious to those familiar with dermatomes of this type.
- the dermatome is operated as follows in the cutting of a graft:
- the dermatome is applied to the body with one end of the intermediate skin-contacting portion A pressed against the skin of the donor area, the protective layer M having been removed from the portion A.
- the body member or drum is then rolled on the donors body with the adhesive layer 43 progressively raising the skin.
- the knife is reciprocated relative to the body member and the skin to cut the latter in the form of a graft.
- the entire graft-transfer member is removed from the dermatome, and the graft 6. applied to the injured area, preferably without removal from the graft-transfer member. It will be apparent that by leaving the graft on the graft-transfer member, shrinkage or wrinkling of the graft is prevented.
- Fig. 5 illustrates a graft (ill applied to the injured area 61 of a patients body 52, the graft 60 being retained in place and protected by the graft-transfer member, to which the graft is still attached. Strips E3 of adhesive tape may be used to retain the graft-transfer member in place on the patients body, as illustrated.
- a tautly drawn graft-receiving or transfer member such as herein described, and originally disclosed in my copending application, Serial No. 583,983, filed March 21, 1945, is that a much thinner graft can be out than would be possible if the graft had to be removed from the adhesive surface prior to being applied to the injured area.
- a taut graft-transfer member By use of a taut graft-transfer member, a graft of two thousandths of an inch thickness may be cut and applied to the injured area without injury to the graft, where, such a thin graft would be torn or otherwise damaged if it were removed from the adhesive coating prior to being applied to the injured area, and even if successfully removed would be clinically unmanageable.
- the degree of surface contact, or the force tending to hold the member to the working face will vary at different areas of the meeting surfaces, resulting in cutting a graft of non-uniform thickness. If it is attempted to cut a graft as thin as two-thousandths of an inch, the graft is likely to be too thin in spots Where the surface contact is slight, or even to have holes therethrough.
- an opening 66 is out in the protective layer 44, by the operator, which opening is of the shape and size of the graft to be cut. the layer 44 overlying the remainder of the intermediate portion A serving to mask the adhesive layer 43, so that the donor area skin will adhere to the graft-transfer memher only through the opening 66.
- Figs. 1 and 2 The mechanism for securing the graft-transfer member to the dermatome and for drawing it taut against the convex working face, illustrated in Figs. 1 and 2, is somewhat elementary and only for the purpose of illustrating the principle of the present invention.
- a dermatome indicated in its entirety by the reference character 75, and having a drum or body member l6 comprised by a pair of semi-cylindrical side walls I! and i8, maintained in parallel spacedapart relation by a curved bottom wall 79 having a convex working face 8
- the side walls T. and 18 and the bottom wall is are formed as a unitary casting.
- a cylindrical handle 82 bridges the space between a pair of ears 83 projecting beyond the straight edges of the side walls T'I'and 18,1the longitudinal axis of the handle :coinciding :with the axis of. generationof the-convex working sure faceBI;
- -the handle :82 is. knurled; as at 84, to provide an improveds-grip-for -the.-operators hand.
- the handle 82 is hollowpas at 85, for passage therethrough of a shaft .86; which is *journaledin hardened steel bushings 81-, pressed-into counter-bores88 at the'ends of the handle 82.
- the bushings -81 notonly serve as bearings for the-shaft 85, but also retain the handle 82 in position with'respect to the ears 83 of the side walls 'II--'i8.
- the bushings 8i areprovided with terminal fiangestll,v abutting the sidewall ears 83 and prevented from rotating relative thereto'by pins 9i extending through the flanges S9 and the ears-83.
- the shaft 85 has one-ofits terminal portions 92, of reduced diameter, permanently secured in the mating-opening 93 of an adjustment body 94, by a pin 95 extending through. theadjustment bodyand theterminal portion.
- the shafts other terminal "portion 96 is threadedly received in the-mating opening 9'! of an adjustment body 88 andthe latter is retained in a position of parallelism with respect to the-other adjustment body Sid-by the set screw 99.
- the spacing of the adjustment bodies 94- and Won the shaft 86 is materially greater than the-width of the body member IS, with the-result thatlimited reciprccatorymovement of the shaft relative to the body; member is, obtainable.
- Bothf the adjustment bodies are provided with axial bores IOI, whose axes extend normal to theaxis ofthe shaft 86 and parallel to each other.
- An adjustment bushing 162 is rotatably mountedin each bore I DI, and is prevented from longitudinal movement therein by a flange I03, abutting the lower edge of the adjustment body, as at IM, and by an adjustment knob I05, secured on the upwardly-projecting end I of the adjustment bushing by a pin N31.
- the lower edge of the adjustment knob I05 abuts the upper edge of 'theadjustment body, as at I 08.
- the adjustmentknobs- I05 are provided with knurled edges, as at I09.
- Theadjustment bushings I02 have internally threaded bores III forreception of correspondingly threaded arms II2. Preferably, these threads are relatively. fine, for example, forty threads to the inch, to secure a highdegree of accuracy in adjusting the arms I I2..by rotation of the adjustment knobs I05 and their associated bushings "I02, while thearms II2 are'prevented from rotating.
- the bottom of each head i I3 is a fiat surface I I4, lying'in-a plane disposed at an angle (preferably 120 degrees) to the longitudinal axis of the arm I I2,
- One side of the headgI I3. is provided with a right-angle notch I I5, whose surface I I6 is parallel to the. surface II I.
- a passage I H of circular cross section, extends through the head H3 at rightangles to. the parallel surfaces IM and I and pted to rotatably receive the body I I 8 of the bladebar lock nut I I9.
- the blade bar lock nut'body I I8 has a twodiameter bore, the smaller diameter I 21 of "the bOIebBliigihl'BfidGd; and: the larger diameter I22 being-smooth-walled.
- a guide pin I23 is adapted for reception in the two-diameter-bore I2IJI22, the smooth guiding portion. I24 of the pin fitting closelyin the bore: I22, and the threaded tip I25- of. theguide pin being threadedly received in the'bore I2I of the lock nut body II8.'
- a pair of the guide'pins I23 extend perpendicularly from-the'upper surface I26'of a blade bar I2I (Fig. 9), the two guide pins being spaced apart av distance corresponding to the spacing of the'two circular passages IIIinthe heads I I3;
- a knife orblade I28 (Fig, 10), is adapted'to rest on the blade bar I21, and 'isrprovided with apair of notches I29 for reception of the pair of guide pins I23, the latter serving to position the blade longitudinally and to limit forward movement thereof. Rearward movement of the blade I28'is limited by an upwardly-projecting rib -I3I at the back of the blade bar, (Figs. 8 and 9); It will be apparent that tightening of the blade bar lock nuts I I9 will draw the blade bartowards the bottom surfaces H4 of the heads II 3, with the blade -I 28 clamped therebetween.
- the blade bar is provided with a pair of upwardly-projecting-pins I32, adapted "to be received in mating recesses I33 in the bottom surfaces I Id of the heads II 3.
- the longitudinal spacing and positioning of the pins I32 0n the blade bar I21 corresponds to that of the guide pins 23, with the result that-the pins I32 'do not interfere in any way with the-blade I28, as they extend freely through the notches I29 of the latter.
- Adjustment for varying the thickness of rafts (Figs. 8, 9, 10 and 16) It is preferred that variations in the thickness of the grafts out be obtained by the use of shims I34, Fig; 16, positioned between the blade and the heads I E3, the shims being provided with notches I35 receiving the guide pins I23, (Figs. 3 and 13).
- Each dermatome is equipped with a set of pairs of shims of varying thicknesses, which may be used in single pairs or in various combinations of pairs to obtain any desired spacing 'of-the blade cutting edge I36 with respect to the dermatome convex surface 8i.
- the adjustmentv knobs I05 are turned in Whichever direction is-necessary to space the cutting edge of the blade fromthe convex surface of the dermatome, an. arbitrary distanceof four thousandths of an inch.
- the adjustment mechanism is-held in the desired position by a wedging lock pin I31, provided with a concavity I38 in one edge thereof, the cavity I38 receiving the side of the adjustment bushing I62, (Figs. 6, '7; 8and 11).
- the loclnng pin I3! is urged axially by a finger nut I39 threadedon the projecting terminal portion ldI-thereof. Further locking of the adjustment mechanism is obtained by turning the lock nut I42 upwardly on the-threaded arm I I2,- until the-nut tightly engages the lower end of the adjustment bushing Hi2.
- the outting-motion-imparting handle Figs. 6 and 7) The post 98 is provided, at the side thereof away from the drum or body member IS, with a handle M3, secured thereto in any suitable manner, for example, as by soldering or brazing, at Md.
- the handle includes a depending portion I 35 around which two or three of the operators fingers may be placed for pulling the blade and its carrying mechanism, and an upwardly-projecting portion I46, against which the operator's thumb may bear for pushing the blade and its carrying mechanism.
- thumb rest portion I46 extends upwardly at least as high asthe top of the adjustment knob N35 to form a guard therefor, preventing accidental turning or misadjustment of the knob H95 by pressure of the operators thumb thereon, were the guard not provided.
- a fixed clamping block I50 extending between the side walls ll-I8.
- the block has terminal portions, each of two diameters l5I and i522, the larger diameter portions I5I extending through mating openings I53 in the side walls and the smaller portions [52 projecting therebeyond and through washers 154, to which they are connected in a suitable manner, as be peaning, at I55.
- a clamping bar 56 extends between the side walls 'l'-i8 in parallel relation to the clamping block E53, and is mounted for limited pivotal movement on a pin I51 extending through aligned openings I53 in a pair of cars fill-460, formed integral with, and projecting rearwardly from, the clamping bar I56 near its ends, (Figs. 12 and 13).
- This pin I51 has its terminal portions IGI fixedly secured in the side walls ll-18, and is so disposed with respect to the clamping block l50 that when the clamping bar I56 is moved in a counterclockwise direction, as viewed in Figs. 13 and 15, its clamping face I62 engages the cooperating clamping face "$3 of the clamping block I59.
- the clamping faces [82 and H53 are serrated or toothed, as at 16k, to provide for positive gripping of the attaching portion 3 at the forward end of the graft-transfer member 40 if) when the same is inserted in the clamping mechanism.
- the ear I59 is provided with an extension or lever I85 adapted for manipulation by a finger of the operator.
- the clamping bar I 56 will be wedged in clamping position, but with only the forward end of the graft-transfer mem-' ber secured, and no pull applied thereto, the clamping bar might be accidentally moved from clamping position.
- the extension or lever I65 is provided with a locking member or latch I56, pivoted at one end to the end of the lever I55 and adapted to swing between a locking position where it overlies the lever I65 (Fig. 12), and a releasing position (Fig. 14).
- the edge IBI of the latch When in looking position, the edge IBI of the latch is received beneath the latching pin. IE8, extending inwardly from the wall TI.
- the lever I65 When the latch is in releasing position, the lever I65 may be moved upward to separate the clamping faces I62-I63. In order that the lever may clear the latching pin I88 during such movement, it is provided with a clearance notch or groove I69 in its outer edge.
- the latch IE6 is provided with an upwardly-directed flange I'II to facilitate movement thereof, by the operator, from looking position.
- Rear holding and tightening ratchet mechanism (Fig.9.13, 17,18, 19, 20 and 21) Means are provided adjacent the rear, or left end as viewed in Figs. 12 and 13-, of the dermatome convex surface BI for holding the rear end of the graft-transfer member fill and for tightening the intermediate portion A thereof against said convex surface.
- a ratchet shaft I15 extends between the dermatome side walls IT-'13, in parallel relation to the rear edge I16 of the convex wall 19, and at a considerable distance below the same,
- One end of the ratchet shaft H5 carries a stub journal ITI rotatably mounted in a flanged bushing H3, pressed into a countersunk opening I19 in the side wall I8, (Fig. 18).
- the opposite end of the ratchet shaft is provided with a stub journal NH, rotatably mounted in a flanged bushing I82 d isposed in a countersunk opening I83 in the side wall ll.
- the stub journal I8I has its terminal portion I81 extending a material distance beyond the side wall IT.
- the periphery of the terminal portion I84 is provided with an annular series of ratchet teeth I85, for a purpose to be explained later.
- the ratchet terminal portion I84 has an axial bore I86, and a pin is! eXterlds diametrically thereof for engagement by the spaced jaws I88 of a wrench I39 (Fig. 21).
- the wrench jaws I88 are formed at the endof a nose portion.
- ISL which is of a diameter permitting its ready insertion in the axial bore I26 of the ratchet terminal portion 84, with the pin 18? between the jaws I8 8. It will be apparent that rotation of the wrench I89 will correspondingly rotate the ratchet shalt I15.
- the cylindrical body of the wrench is knurled, as at IE3, for easy gripping by the operator.
- the cylindrical body is provided with diametrically-opposed flat portions file to prevent rolling thereof when laid on a flat surface, such as a table top.
- a ratchet plate I is secured to the outer surface of the side wa11 H by screws Hi8, the plate we having an opening to? therethrough for unrestricted passage of the ratchet terminal portion I84.
- the toothed portion of said ratchet terminal is of such length that a, material part thereof projects beyond the ratchet plate I for engagement by a pawl I98, pivotally mounted. on the ratchet plate I05 by the pin I99.
- the pawl I98 is biased to engagement with the ratchet teeth I35 by a wire spring 20I formed with a loop 252 at one end by which it is mounted on the ratchet plate byone of the screws I96, which passes through said loop.
- the other end 203 of the spring 20I is loosely received in an opening 204 extending through the handle 205 of the pawl I93, with the springend 203 bearing against one wall of said opening.
- the ratchet shaft I15 is slotted, as at 206, for substantially the entire distance between the dermatome side walls 11-18, for reception of the rear end of the graft-transfer member 40 (Figs. 18, 19 and 20).
- a cam shaft 2 is positioned between, and in parallel relation to, the rear edge I16 of the convex wall 19 and the ratchet shaft I15, with one terminal portion 2 thereof rotatably journaled in the flanged bushing 2I2 which is pressed into the countersunk opening 2I3 of the side wall 18.
- the other terminal portion 2M is rotatably journaled in a bushing 2I5, formed integral with the ratchet plate I95 and closely received in the Opening 2I6 in the side wall 11.
- This terminal portion 2M is of sufiicient length to project beyond the ratchet plate, and the projecting part is provided with a series of ratchet teeth 2I1 which preferably extend through a limited portion only of the periphery of the terminal 2M, for a purpose to be hereinafter explained.
- the cam shaft terminal portion has an axial bore 2I8, provided with a pin 2I9 extending diametrically thereof, the bore 2I-8 and pin 2I9 corresponding in structure and function to the bore I86 and pin I81 of the ratchet shaft I15, with the result that the same wrench I89 serves to rotate both the ratchet shaft and the cam shaft.
- a pawl 22I is urged into contact with the ratchet teeth 2I1 of the cam shaft by the same spring 20I which exerts a biasing effect on the previously-described pawl I98.
- the pawl 22I is pivotally mounted on the ratchet plate I95 by a pin 222, with a pair of spaced bearing portions 223 and 224 contacting an intermediate section of the wire spring 20I (Fig. 17)
- the cam shaft periphery 225 is eccentric relative to the journals thereof, with the resultthat as the shaft is rotated, the line 226 on the periphery 225 which is farthest from the center of rotation 221, moves in the path indicated by the dotted line C, in Fig. 17.
- the rearward end of the transfer member is brought around the outside of the convex surface 8
- the free rear end of the transfer member is directed upwardly through the slot 206 in the ratchet shaft I15, with a terminal portion 226 extending therebeyond (Fig. 19), and adapted to be doubled back and overlapped when the ratchet shaft is rotated by the 12 wrench (Fig. 20).
- the cam shaft ZID While the ratchet shaft is being turned to draw the graft-transfer member taut, the cam shaft ZID is in its inactive position, as shown in Fig. 19.
- the series of ratchet teeth 2I1 thereof is interrupted by a smooth portion 221.
- the wrench is applied to the cam shaft and the latter rotated until the smooth portion 221 passes beneath the pawl 22I and the latter engages the first tooth 2I1.
- This action will result in a quiet turning of the cam shaft, followed by a click as the pawl drops into the notch beside the first tooth, this first click indieating to the operator that the cam is in inactive position. This signal will be discernible to the operator both by ear and by feel.
- ing action of the shaft is limited to increments I corresponding to the angular movement between adjacentr teeth on the ratchet shaft. For example, if a tightening action corresponding to five and a half teeth was required, there would be no way to hold the last half-tooth of motion.
- This final tightening corresponding to a fraction of a tooth on the ratchet shaft, is obtained by rotation of the cam shaft from inactive position towards a position of maximum action or eccentricity, i. e. from the position of Fig. 19 to that of Fig. 20. Any additional tightening obtained by rotation of the cam shaft is retained by engagement of the pawl 22I with the teeth 2I1. It will be noted that not only are the teeth of the cam shaft closer pitched than those of the ratchet shaft, but a full half-turn of the cam from minimum to maximum eccentricity produces much less total movement of the graft-transfer member than a full turn of the ratchet shaft. Therefore, tightening action over several teeth on the cam shaft is required to equal that of one tooth on the ratchet shaft.
- the rearward end of the transfer member is released simply by pulling thereon lightly, while pressing on the handle 205 of the pawl I98 to disengage the latter from the teeth I of the ratchet shaft, the shaft rotating until the transfer member is unwound therefrom and slips out of the slot 205.
- the adhesive or cement which is applied to the patients donor area skin may adhere to the exposed edge portions of the convex surface, in which event the blade will cut a graft including the areas of the exposed edge portions, and the corresponding edge portions of the graft so cut will be so much thicker than the rest of the graft as to constitute beads, the blade cutting below the patients skin and into the fatty tissue.
- the dermatome of Figs. 6 to 21, inclusive has the side edges of its convex surface 8
- a dermatome for cutting grafts from adults have a. convex surface approximately four inches wide and eight inches long, so that a graft of thirty-two square inches may be obtained at one cutting. Frequently, a cut of less than thirty-two square inches is desired, and difficulty may be encountered in determining accurately how far around the drum to cut to obtain the desired area.
- the present invention meets this difiiculty by providing, at the semicylindrical edge of one or both of the side plates l1 and 18, a series of graduations or indicia 233, preferably expressed in inches and fractions thereof, and starting at the front, or right-hand edge, as viewed in Figs. 13 and 15.
- Narrow drum dermatome (Figs. 22 and 23) While, as previously indicated, a drum having an effective width of approximately four inches is preferred for use with adult patients, in the case of children and some types of adult work a narrower drum is preferable due to limited donor areas available. A drum having an effective width of two and a half inches is desirable in many instances. However, it has heretofore been thought that a drum of less than four inches width was impractical, due to the space necessary between the drum side walls for the operators fingers in gripping the handle of the dermatome.
- Figs. '22 and 23 there is illustrated a dermatome whose drum has an efiective width of only about two and a half inches, yet which provides ample space for the operators fingers.
- This dermatome is identical to that previously described in connection with Figs. 6 to 21, inclusive, except for the drum 258 and the l ngth of the shaft 86. l
- the drum or body member 255 comprises a central web 25-1, preferably cast integral with the convex wall 252, the handle core 253 and the pair of low side walls 25 and 255.
- the handle core 253 is axially bored, as at 256, and counterbored at each end, as at 251, for reception of hardened steel bushings 258 in which the shaft 86" slides and rotates.
- Knurled sleeves 258 are pressed on the handle core 253 from opposite ends thereof, and abut the upper edge of the central web 25!.
- the central web extends for onl about the central third of the front-to-rear overall dimension of the drum, as viewed in Fig. 23, with the result that there is no interference with the transversely-extending clamping block and bar, and with the ratchet and cam shafts.
- the central web 25! is provided with flanges 263 at its front and rear edges, which flanges are integral with the convex wall 252 and extend laterally a short distance from the central web 25, to further stiffen the latter.
- the inner edges 25 9 f the side walls 254 and 255 are spaced radially from the handle a distance amply sufficient for the operators fingers when the handle. 259 is gripped.
- all of the modifications of dermatomes herein .shown and described are provided with aligned openings in the side walls near the convex wall and substantially midway of the length of the latter, as at 55 in Figs. 1 and2, at 89 in Figs. 6 to 21, inclusive, and at 2M in Figs. 22 and 23.
- These openings are used in positioning the dermatomes on stands or supports during adjustment of the various mechanisms, both prior to, and following, the cutting of grafts.
- these openings may be provided with bushings, as at 90 in Figs. 6 to 21, inclusive, and at .252 in Figs. 22 and 23.
- the drums or body members are made of cast brass, and all the remaining parts which are permanently associated therewith are manufactured of stainless steel.
- the combination of these two metals has the advantage that their coefficients of expansion are so nearly alike that no binding, misalignment or warping of associated parts occurs when the instrument is subjected to the relatively high temperatures encountered when sterilizing the same.
- l. .A dermatome including :a body member comprising a pair of approximately semi-cylindrical spaced parallel side walls joined along their convex edges by a curved bottom wall having a convex outer surface, and means for supporting a graft-cutting blade from said body member for cutting movements in parallel relation to the convex outer surface, the width of said convex surface being approximately the same as the space between said side walls.
- a dermatome including a body member comprising a pair of spaced parallel side walls joined by a curved bottom wall having a convex outer surface, and means adapted to support a graftcutting blade from said body member for cutting movement parallel to said convex outer surface, said curved bottom wall having its convex outer surface at its side edges relieved an amount approximately equal to the thickness of the side walls.
- a dermatome comprising a body member including a pair of semi-cylindrical side walls disposed in parallel spaced-apart relation and a bottom wall joining said side walls at their convex edges and having a convex outer surface; means adapted to support a graft-cutting blade from the body member for cutting movement parallel to said convex outer surface, and means for retaining a graft-transfer member against said convex outer surface with a portion of said transfer member disposed between said spaced side walls, the effective width of said convex outer surface corresponding approximately to the spacing of said side walls.
- a dermatome comprising a body member having a convex outer surface, means adapted to support a graft-cutting blade from said body member for cutting movement parallel to said convex outer surface, means for securing one end of a flexible graft-transfer member to the dermatome, means for securing the other end of graft-transfer member to the dermatome with the intermediate portion of said transfer member against said convex outer surface and for pulling said transfer member in increments to tighten said intermediate portion, and cam means for tightening said transfer member a portion of one of said increments.
- a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut, means carried by the body member and adapted to hold one end of the graft-transfer member, means adjusttable in predetermined increments and adapted to tighten and hold the other end of said graft-transfer member with the intermediate portion of said transfer member engaging the convex surface of the body member, and means for further tightening said transfer member in fractions of said predetermined increments.
- a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut, means for holding each end of said transfer member to the body member, the means for holding one of said ends comprising a pair of clamping members, one of which is movable toward and away from the other into and out of clamping relation, and means by which such movement may be imparted to the movable clamping member.
- a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut; a first means for holding one end of said grafttransfer member to said body member; and a second means for holding the other end of said graft-transfer member to said body member, said second means comprising a rotatable shaft, means for securing said other end of the rafttransfer member thereto, and means for applying rotary motion to said shaft to draw said graft-transfer member taut against said body member convex surface.
- a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut; first means carried by the body member for holding one end of said graft-transfer member thereto; a shaft rotatably journaled on said body member; means for securing the other end of said graft-transfer member to said shaft with the intermediate portion of said transfer member disposed against said body member convex surface; and means for transmitting rotary motion to said shaft, whereby said graft-transfer 16 member is drawn taut against said convex surface.
- a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut; clamping means carried by the body member for securing one end of the graft-transfer member thereto; a shaft rotatably supported by said body member; means for securing the other end of said graft-transfer member to said shaft with the intermediate portion of said graft-transfer member positioned against said body member convex surface; a ratchet carried by said shaft; a pawl having a stationary pivotal support relative to said body member and adapted to cooperate with said ratchet to retain said shaft in rotated position with said graft-transfer member taut; and a second shaft eccentrically journaled in said body member and adapted, when rotated, to bear with gradually-increasing pressure against an unsupported portion of the grafttransfer member intermediateits points of securement by the clamping means and the firstmentioned shaft.
- a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut; first and second securing devices carried by said body member for fastening opposite terminal portions of the graft-transfer member to the body member, one of said securing devices including mean-s for drawing said graft-transfer member taut against the body member convex surface.
- a dermatome comprisin a body member having a pair of side walls joined at one edge by a curved bottom wall having a convex outer surface, bearing structure carried by said pair of side walls, a shaft journaled in said bearing structure for rotary and reciprocatory movement relative to said body member about and along an axis coinciding with the axis of generation of the convex outer surface, a pair of posts carried by the terminal portions of said shaft and extending radially of the latter in parallel relation at opposite sides of the body member, a head at the outer free end of each of said posts, blade-supporting means carried by said heads and bridging the space therebetween, means for adjusting said blade-supporting means toward and away from the heads, and means for adjusting said heads toward and away from the shaft.
- a dermatome comprising a body member having a convex outer surface, bearing structure carried by said body member, a shaft journaled in said bearing structure for rotary and reciprocatory movement therein relative to said body member about and along an axis coincidingwith the axis of generation of the body member convex outer surface, a frame carried by said shaft and including a member adapted to support a blade with its cutting edge in close proximity to said convex outer surface, first adjusting means 17 for obtaining parallelism between the cutting edge of a blade supported by said frame and said convex outer surface, and secondadjusting means for varying the spacing f said blade-cutting edge with respect to said convex outer surface.
- a dermatome comprisin a body member having a convex outer surface; bearing structure carried by said body member; a shaft journaled in said bearing structure for rotary and reciprocatory movement; a frame carried by said shaft and including a, pair of spaced, parallel posts at opposite sides of the body member and a blade-supporting member carried by the free outer ends of said posts and adapted for movement parallel to and at a predetermined distance from said convex outer surface, each of said posts including a threaded arm, a rotatable adjusting sleeve threaded on said arm, means for preventing rotation of said arm during rotation of said adjusting sleeve, whereby rotation of said adjusting sleeve will vary the effective length of the post, and a head carried by said arm and to which the blade-supporting member is secured, and means carried by each of said heads for securing said blade-supporting member thereto, said last-mentioned means urging the blade-supporting member towards the heads to clamp a blade between said member
- a pawl assembiy comprising a supporting plate having a pair of openings therethrough for free passage of the ratchet-toothed portions of said pair of shafts, a pair of pawls pivotally mounted on said supporting plate in position to engage the shaft ratchet teeth when said shaft toothed portions extend through said openings, and a spring mounted on said supporting plate for tensioned engagement with both of said pawls and adapted to urge the latter into mating relation with the shaft ratchet teeth.
- Apparatus of the character described comprising a body member having a convex surface; a shaft supported by said body member for rotary and reciprocatory movement relative thereto; a pair of posts carried by the terminal portions of said shaft at opposite sides of the body member and in parallel relation; means for adjusting the length of each post radially of the shaft, said means including an adjusting knob at the upper end of each post; means supporting a blade from the lower ends of the pair of posts with the Cutting edge thereof disposed in close proximity, and parallel to, the convex surface of the body member; and a handle carried by one of said posts and adapted to be gripped by the operator of the apparatus to impart the desired rotary and reciprocatory motion to the shaft, posts and blade relative to the body member and its convex surface, said handle including a first portion adapted to be engaged by the operator's fingers and a second portion adapted to be engaged by the operators thumb, said second portion being disposed between the adjusting knob and the operators thumb when the handle is gripped, whereby accidental turning of said adjusting knob by contact
- a body member comprising a curved wall of uniform width having a convex outer surface; a pair of side wallsextending from the side edges of said curved wall radially inward relative tothe axis of generation of said convex outer surface; a centraiwan parallel to, and substantially midway of, said side walls and extending radially-inward.
- a handle carried by said central wall and extending transversely relative to said central and side walls and being spaced radially from the inner edges of the latter: a shaft journaled in said handle for rotary and reciprocatory motion relative to said body member, the longitudinal axis of said shaft coinciding with said axis of generation of the convex outer surface; and means for supporting a blade from said shaft with its cutting edge adjacent and parallel to said convex outer surface.
- a body member comprising a curved bottom wall having a convex outer surface and parallel side edges, a central wall extending upwardly from the bottom wall substantially midway of, and parallel to, the side edges of the curved bottom wall, and a handle carried by said central wall; a shaft journaled in said handle for rotary and reciprocatory movement relative to said body member; and means carried by said shaft for supporting a blade with its cutting edges adjacent and parallel to said convex outer surface.
- a body member comprising a curved bottom wall having a convex outer surface against which a flexible graft-transfer member is adapted to be held, a pair of parallel side walls extending upwardly from the side edges of said bottom wall towards the axis of generation of said convex outer surface, a central wall parallel to, and midway of, said pair of side walls, and a handle carried by said central wall and extending transversely thereof; a.
- the method of transferring a skin graft from a donor area to an injured area which comprises; temporarily retaining a flexible, adhesive-coated graft-transfer member taut against a convex surface with the adhesive coating exposed; rolling the convex surface, with the grafttransfer member taut thereon, over the donor area, thereby causing the skin of the donor area progressively to adhere to said.
- graft-transfer member through the action of said adhesive coating, said rolling action thereby lifting said skin; cutting the lifted skin simultaneously with the rolling action, while maintaining the line of sev- ,erance a predetermined distance from the grafttransfer member; removing the graft-transfer member, with the graft thereon, from the convex surface; positioning the graft on the injured area without removing it from the graft-transfer member; and retaining the graft in position by means of the graft-transfer member.
- a dermatome the combination of a body member having a working face, means for supporting a cutting member for cutting movement parallel to said working face and at a predetermined distance therefrom, and means for mechanically securing taut against said working face a flexible graft-receiving member.
- a body member having a. convex working face, means adapted to support a knife for cutting movement parallel to said working face and at a predeterhaving a convex working face; a pair of parallel,
- a dermatome comprising a body member having a convex working surface rockable on a patients body; means for securing a flexible graft transfer member, having an adhesive facing, taut against the convex surface, whereby rocking of said body member will progressively lift an area of skin by adhesion of the latter to the taut graft-transfer member; and means for supporting a knife a predetermined distance from the convex surface for cutting movement to that it may progressively cut a graft of the skin as the latter is lifted.
- a dermatome comprising a body member having a convex surface; means for mechanically temporarily retaining a flexible graft-transfer member, having an adhesive skin-engaging surface, on said convex surface; and means for supporting a graft-cutting member a. predetermined distance from the convex surface for cutting movement parallel thereto.
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Description
June 1, r 4 J. D. REESE 3 DERMATOME V Filed Sept. 25, 1945 5 Sheets-Sheet 1 INVENTOR. J'oHrJ D. EEEsE BY W K ATToEA/E]:
June 1948. J. D. REESE 2,442,434
DERMATOME Filed Sept. 25, 1945 5 Sheets-Sheet z --j]) 10 INVENTOR. I! 11 J). EE E 5 E BY 11 WT FM June 1, 1948. J. D. REESE 2,442,434
DERMATOME Filed Sept. 25 1945 5 Sheets-Sheet 5 INVENTOR. J'oHd 1 ZEE5E BY ATTOEJJEY J. D. REESE June 1, 1948.
DERMATOME 5 Sheets-Sheet 4 Filed Sept. 25, 1945 INVENTOR. J'cwlld ID. 55555 ATTOBIJEY.
June 1, 1948. J. D. REESE 2,442,434
I DERMATOME Filed Sept. 25, 1945 5 Sheets-Sheet 5 ms I INVENTOR. MM ID. EEEsE ATTolZrJEY.
Patented June 1, 1948 tJNlTED STATES PATENT OFFICE DERMATOIME John 1). Reese, Philadelphia, Pa.
Appiicaticn September 25, 1945, Serial No. 618,523
29 Claims.
This invention relates to surgery, more particularly to skin grafting, and has for an object to provide an improved dermatome for cutting a skin graft.
Another object of the invention is to provide, in a dermatome of the type comprising a body member having a convex working face and a knife supported by the body member for cutting movement parallel to said convex face and at a predetermined distance therefrom, improved means for adjusting the spacing of the knife with respect to the convex working face.
While the improvements of the present inven tion may be used with almost any type of dermatome, they are particularly applicable to the type having a convex working face, as illustrated by United States Letters Patent No. 2,288,709, granted July 7, 1942, to G. J. Hood, and by applicants prior Patent No. 2,366,05e, granted December 26, 1944.
In using dermatomes of this type, it has been the practice to apply a coat of liquid adhesive or cement to the convex working face, and a similar coat to the skin of the donor area, or to stick to the dermatom Working face a rubber sheet of proper size and shape, coated on both sides with a soft adhesive rubber compound. The convex face was then rolled on the adhesive-coated donor area, and simultaneously a knife, supported by the dermatome for reciprccatory and oscillatory movement parallel to the convex face, was given a cutting motion to separate the graft from the donor area as the skin thereof was raised by the adhesive during the rolling action. After completion of the cutting operation, the graft was removed from the adhesive, applied to the injured area, and retained in position thereon by sutures or clamps.
Where the convex surface was coated with adhesive or cement, the difficulty was frequently encountered that the coating pulled away from the surface in spots, with the result that at such spots the skin was not raised, the knife cut holes in the graft. The same dificulty arose where the rubber sheet, coated on both sides with rubber adhesive, was relied upon, as the adhesive retaining the rubber sheet on the dermatome convex face likewise tended to pull away in spots, resulting in the cutting of holes in the graft.
Also, it has been proposed to retain a rubber sheet, having adhesive on only its outer skinengaging face, in position on the convex working face of a dermatome, solely by suction. Here again, difficulty may be encountered in obtaining a satisfactory graft, mainly because of fallure of the graft-receiving rubber sheet to remain tight against the dermatome, due to unreliability of such suction apparatus. Whether the'rubber sheet is held in place by adhesive or by suction, it is subject to wrinkling or partial separation from the dermatome because of non-uniformity of securing action.
Therefore, another object of the invention is to provide, in a dermatome, means for positively securing a graft-receiving member against a convex working face, with the contact pressure between the member and the face uniform at all points therebetween.
A further object of the invention is to provide a dermatome having means for mechanically securing against its WOrking face, a graft-receiving member of flexible material.
Yet another object of the invention is to provide a dermatome having means for mechanically securing to its working face, a graft-receiving member of flexible material, together with means for drawing said member taut against said working face.
Another object of the invention is to provide a dermatome constructed of a combination of such materials as will result in uniform expansion and contraction of all parts thereof when the dermatome is sterilized at high temperatures.
These and other objects are eifected by the invention as will be apparent from the following description and claims taken in accordance with the accompanying drawings, forming a part of this application, in which:
Fig. 1 is a front elevational view, partially in section, of a dermatome embodying features of the present invention;
Fig. 2 is a vertical sectional view, taken along the line II1I of Fig. 1, looking in the direc tion indicated by the arrows;
Fig. 3 is a plan view of a graft-receiving or graft-transfer member, adapted for use with the dermatome of the present invention, portions thereof being broken away at one corner to more clearly illustrate the laminated construction;
Fig. 4 is a view similar to Fig. 3, showing a modified graft-receiving member;
Fig. 5 is a fragmentary sectional view of the injured area of a patients body, showing a skin graft retained thereon;
Fig. 6 is a front elevational view of an improved dermat-ome, constructed in accordance with the present invention;
Fig. '7 is a transverse sectional view of the dermatome shown in Fig. 6, and taken along the 3 line VIVI of Fig. 12, looking in the direction indicated by the arrows:
Fig. 8 is an enlarged sectional view, taken along the line VIII-VIII of Fig. 'I, looking in the direction indicated by the arrows;
Fig. 9 is a plan view of the blade-supporting bar;
Fig. 10 is a plan view of the cutting blade;
Fig. 11 is a sectional view taken along the line XI-lfl of Fig. 8, looking in the direction indicated by the arrows;
Fig. 12 is a plan view of the dermatome shown in Figs. 1 and 2;
Fig. 13 is a view of the left end of the dermatone shown in Fig. 6;
Fig. 14 is an enlarged fragmentary plan view of the structure shown at the lower right corner of Fig. 12, with the latch moved to releasing position.
Fig. 15 is an enlarged fragmentary view of the right-hand end of Fig. 13, with the clamping bar in released position;
Fig. 16 is a plan view of one of the shims;
Fig. 17 is an enlarged fragmentary view of the left-hand end of Fig. 13;
Fig. 18 is a fragmentary sectional view, taken along the line XVIII-XVIII of Fig. 13, looking in the direction indicated by the arrows;
Fig. 19 is an enlarged fragmentar sectional view, taken along the line XIX-XIX of Fig. 12, looking in the direction indicated by the arrows, and showing the graft-transfer member in position before tightening;
Fig. 20 is a view similar to Fig. 17, but showing the graft-transfer member in final tightened position.
Fig. 21 is a plan view of the wrench or tool used to adjust the ratchet and the cam;
Fig. 22 is a transverse sectional view of a modified form of dermatone; and
Fig. 23 is a side elevational view, taken along the line 2QIII-XXIII of Fig. 22, looking in the direction indicated by the arrows, the shaft and associated post structure being omitted.
Referring now to the drawings more in detail,
particularly to Sheet 1, Figs. 1, to 5, wherein the principles of the present invention are illustrated broadly, the reference character ill indicates, in its entirety, a dermatone comprising a body portion II in the form of a semi-cylindrical drum I made of a spaced pair of semi-cylindrical side walls l2, joined by a curved end wall 13 having an outer convex working face 14. The side walls 12 carry a bearing i6 bridging the space between the side walls and positioned so that its longitudinal axis coincides with the axis of generation of the convex working face l4.
A shaft I1 is journaled in the bearing [6 for both rotary and reciprocatory movement relative to the body member, and carries at its terminal portions 9. pair of posts Is, which extend radially relative to the convex working face l4, in parallel, spaced-apart relation, with the spacing therebetween considerably greater than the width of the body member or drum l i, to provide for reciprocatory movement of the shaft H and posts l8 relative to said body member.
The posts may be retained on the" shaft terminal portions by a pair of knurled finger nuts l9, although, preferably, a handle or finger piece 2| is used in place of one of the knurled nuts H] to serve as a more suitable grip for the hand of the operator when reciprocating the shaft.
A blade-supporting bar 22 is carried by the outer ends 23 of the posts, and is provided with a pair of lugs 24, slidably received in bores formed in the post ends 23. A knife 21 is adapted to be supported on the bar 22, with its cutting edge 28 in parallel relation to the convex surface H of the drum.
A pair of rods 3|, rotatable in bores 32 of the posts, have threaded connections, at their inner ends 33, with threaded bores in the lugs 24. The outer ends of the rods 3! carry knurled finger pieces 34, by which the rods may be rotated to move the lugs longitudinally of the bores 25 in which they are positioned, inward movement of the lugs serving to draw the bar 22 towards the ends of the posts to securely clamp the knife 2'! thereagainst.
Adjustment of the spacing of the knife with respect to the convex working face M is obtained by inserting between the knife and the post ends 23, shims 36 of the desired thickness.
The structure so far described constitutes, of itself, no part of the present invention, being already known to the art, and a more complete description of the details of construction may be obtained from applicants prior patent, previously referred to.
The present invention provides a dermatome adapted to make use of a skin graft-receiving or graft-transfer member 40, in the form of a flexible sheet. As best shown in Figs. 2 and 3, the graft-transfer member 40 comprises an intermediate strip of fabric 4|, which is so disposed with respect to the sheet that the warp ends extend lengthwise; thereby rendering the flexible sheet substantialy inextensible in a lengthwise direction, the fabric having permanently secured to the lower face thereof, as viewed in Fig. 3, a coating or layer 42 of rubber, whose surface, which is away from the fabric, is dry and smooth, for a purpose to be hereinafter set forth.
On the upper face of the fabric 4! is permanently secured a layer or coating 43 of rubber, whose surface which is away from the fabric is of an adhesive character. To protect the adhesive surface, the latter is covered with a strip of protective material 44, preferably of cloth which has been starched, varnished or otherwise processed.
The graft-transfer member 40 is of a width slightly less than the distance between the body member side walls I2, and of a length materially greater than the developed length of the convex working face l4 of the body member, the excess length constituting securing portions B, at each end of the strip, and the remaining intermediate section constituting a skin-contacting portion A,
In use, the graft-transfer member 40 is applied to the body member of the dermatome, with the smooth inner surface of the rubber layer 42 against the convex working face of the body member, the intermediate skin-contacting portion A terminating adjacent the ends of the convex face. The securing portions B of the member 40 are drawn over the ends of the convex wall [3 and the protective layer 44 may first be removed therefrom, although this is not generally necessary.
To permit ready removal of this protective layer 44 from the end securing portion B, without disturbing the protective layer covering the intermediate skin-contacting portion A, the protective layer 44 is provided with a break at the line where the portion A terminates and the portion B commences, as at 46 in Fig. 3. If desired, the protective layer may be merely weakened by a cut or by a row of serrations or perforations, indicated at 41 in Fig. 4.
Where the member 40 is attached without removal of the protective layer 44 from the attaching portions B, the breaks 46, or cuts or perforations 41, provide the give in the layer 44 -which is necessary to permit the strip 4| to be drawn taut over the convex face of the body member.
In accordance with the present invention, the dermatome is provided with means for mechanically securing the graft-transfer member there- In its broadest form, as illustrated in Figs. 1 to 5, the dermatome side walls l2 are provided, adjacent one end of the curved wall I3, with a pair of slots 50, which are inclined towards said one end of the curved wall, relative to the inner surface of that wall. A knurled bar or roller 5! has its terminal portions mounted in the slots 50, for free rolling or sliding movement therein. The adjacent securing portion B of the grafttransfer member is positioned in the space between the bar 5! and the inner surface of the curved wall i3, any pull on the securing portion B in an upward direction, as viewed in Fig. 2, resulting in wedging of the bar 5| against the portion B, thereby preventing withdrawal of the latter.
The securing portion B at the opposite end of the graft-transfer member may be held by a quick-release latch or dog 52, pivoted at 53 to the side walls 12, and having a grip 54 and handle 56, as well as a stop 5?. The entire latch or dog may be of well known construction, such as is frequently used in buckles.
In order to hold the intermediate portion A of the graft-transfer member taut against the convex working face of the dermatome, there is provided a tightening rod 58, pivotally mounted in opposed openings in the side walls It, and formed with a cam surface eccentric relative to its axis of rotation. One end of the rod 58 may extend beyond the corresponding side wall I2, and carry a knurled finger piece 59, by which the rod may be rotated to cause the cam surface thereof to raise the graft-transfer member where it passes thereover, to draw the member taut. In order to distribute uniformly throughout the length of the graft-transfer member the stress to which the latter is subjected when drawn taut by the cam rod 58, the inner convex-face-engaging surface of the graft-transfer member is made smooth and dry, so that it may slip easily on said convex face.
Preferably, the protective layer M is left on the intermediate skin-contacting portion A until such time as the graft is to be cut, when the layer M is removed and the graft cut in a manner obvious to those familiar with dermatomes of this type.
Briefly, the dermatome is operated as follows in the cutting of a graft: The dermatome is applied to the body with one end of the intermediate skin-contacting portion A pressed against the skin of the donor area, the protective layer M having been removed from the portion A. The body member or drum is then rolled on the donors body with the adhesive layer 43 progressively raising the skin. Simultaneously with the rolling of the body member, and consequent raising of the skin, the knife is reciprocated relative to the body member and the skin to cut the latter in the form of a graft. Upon completion of the cutting, the entire graft-transfer member is removed from the dermatome, and the graft 6. applied to the injured area, preferably without removal from the graft-transfer member. It will be apparent that by leaving the graft on the graft-transfer member, shrinkage or wrinkling of the graft is prevented.
Further, after the graft and its transfer member have been applied to the injured area, the transfer member may be used to retain the graft in place, thereby eliminating the use of sutures or clamps. Fig. 5 illustrates a graft (ill applied to the injured area 61 of a patients body 52, the graft 60 being retained in place and protected by the graft-transfer member, to which the graft is still attached. Strips E3 of adhesive tape may be used to retain the graft-transfer member in place on the patients body, as illustrated.
An important advantage of the use of a tautly drawn graft-receiving or transfer member, such as herein described, and originally disclosed in my copending application, Serial No. 583,983, filed March 21, 1945, is that a much thinner graft can be out than would be possible if the graft had to be removed from the adhesive surface prior to being applied to the injured area. By use of a taut graft-transfer member, a graft of two thousandths of an inch thickness may be cut and applied to the injured area without injury to the graft, where, such a thin graft would be torn or otherwise damaged if it were removed from the adhesive coating prior to being applied to the injured area, and even if successfully removed would be clinically unmanageable.
Where the graft-receiving member is secured to the dermatome working face by adhesion, suction, or any means other than mechanical, the degree of surface contact, or the force tending to hold the member to the working face, will vary at different areas of the meeting surfaces, resulting in cutting a graft of non-uniform thickness. If it is attempted to cut a graft as thin as two-thousandths of an inch, the graft is likely to be too thin in spots Where the surface contact is slight, or even to have holes therethrough.
In the construction shown in Fig. 4, an opening 66 is out in the protective layer 44, by the operator, which opening is of the shape and size of the graft to be cut. the layer 44 overlying the remainder of the intermediate portion A serving to mask the adhesive layer 43, so that the donor area skin will adhere to the graft-transfer memher only through the opening 66.
The mechanism for securing the graft-transfer member to the dermatome and for drawing it taut against the convex working face, illustrated in Figs. 1 and 2, is somewhat elementary and only for the purpose of illustrating the principle of the present invention. For a detailed disclosure of what is considered a preferred embodiment of the invention, reference is now made to Figs. 6 to 21, inclusive, on sheets 2, 3 and 4 of the drawings.
Preferred construction of dermatome (Figs. 6, 7, 10 and 11 The above-mentioned figures disclose a dermatome, indicated in its entirety by the reference character 75, and having a drum or body member l6 comprised by a pair of semi-cylindrical side walls I! and i8, maintained in parallel spacedapart relation by a curved bottom wall 79 having a convex working face 8|. Preferably, the side walls T. and 18 and the bottom wall is are formed as a unitary casting.
A cylindrical handle 82 bridges the space between a pair of ears 83 projecting beyond the straight edges of the side walls T'I'and 18,1the longitudinal axis of the handle :coinciding :with the axis of. generationof the-convex working sure faceBI; Preferably;-the handle :82 is. knurled; as at 84, to provide an improveds-grip-for -the.-operators hand.
The handle 82 is hollowpas at 85, for passage therethrough of a shaft .86; which is *journaledin hardened steel bushings 81-, pressed-into counter-bores88 at the'ends of the handle 82. Thus, the bushings -81 notonly serve as bearings for the-shaft 85, but also retain the handle 82 in position with'respect to the ears 83 of the side walls 'II--'i8. Preferably, the bushings 8i areprovided with terminal fiangestll,v abutting the sidewall ears 83 and prevented from rotating relative thereto'by pins 9i extending through the flanges S9 and the ears-83.'
Post adjustment mechanism (Figs. 6, 7, 8 and 11) The shaft 85 has one-ofits terminal portions 92, of reduced diameter, permanently secured in the mating-opening 93 of an adjustment body 94, by a pin 95 extending through. theadjustment bodyand theterminal portion. The shafts other terminal "portion 96 is threadedly received in the-mating opening 9'! of an adjustment body 88 andthe latter is retained in a position of parallelism with respect to the-other adjustment body Sid-by the set screw 99. The spacing of the adjustment bodies 94- and Won the shaft 86 is materially greater than the-width of the body member IS, with the-result thatlimited reciprccatorymovement of the shaft relative to the body; member is, obtainable.
Bothf the adjustment bodies are provided with axial bores IOI, whose axes extend normal to theaxis ofthe shaft 86 and parallel to each other. An adjustment bushing 162 is rotatably mountedin each bore I DI, and is prevented from longitudinal movement therein by a flange I03, abutting the lower edge of the adjustment body, as at IM, and by an adjustment knob I05, secured on the upwardly-projecting end I of the adjustment bushing by a pin N31. The lower edge of the adjustment knob I05 abuts the upper edge of 'theadjustment body, as at I 08. Preferably, the adjustmentknobs- I05 are provided with knurled edges, as at I09.
Theadjustment bushings I02 have internally threaded bores III forreception of correspondingly threaded arms II2. Preferably, these threads are relatively. fine, for example, forty threads to the inch, to secure a highdegree of accuracy in adjusting the arms I I2..by rotation of the adjustment knobs I05 and their associated bushings "I02, while thearms II2 are'prevented from rotating.
EacharmlIZterminatesin a headI I3 of a length sufllcient to' project beyond .the convex surface M of the drum or body member I6. The bottom of each head i I3 is a fiat surface I I4, lying'in-a plane disposed at an angle (preferably 120 degrees) to the longitudinal axis of the arm I I2, One side of the headgI I3.is provided with a right-angle notch I I5, whose surface I I6 is parallel to the. surface II I. A passage I H, of circular cross section, extends through the head H3 at rightangles to. the parallel surfaces IM and I and pted to rotatably receive the body I I 8 of the bladebar lock nut I I9.
Bladesupportingmechanism-(Figs. 8, 9 and 10) The blade bar lock nut'body I I8 has a twodiameter bore, the smaller diameter I 21 of "the bOIebBliigihl'BfidGd; and: the larger diameter I22 being-smooth-walled. A guide pin I23 is adapted for reception in the two-diameter-bore I2IJI22, the smooth guiding portion. I24 of the pin fitting closelyin the bore: I22, and the threaded tip I25- of. theguide pin being threadedly received in the'bore I2I of the lock nut body II8.'
A pair of the guide'pins I23 extend perpendicularly from-the'upper surface I26'of a blade bar I2I (Fig. 9), the two guide pins being spaced apart av distance corresponding to the spacing of the'two circular passages IIIinthe heads I I3;
A knife orblade I28 (Fig, 10), is adapted'to rest on the blade bar I21, and 'isrprovided with apair of notches I29 for reception of the pair of guide pins I23, the latter serving to position the blade longitudinally and to limit forward movement thereof. Rearward movement of the blade I28'is limited by an upwardly-projecting rib -I3I at the back of the blade bar, (Figs. 8 and 9); It will be apparent that tightening of the blade bar lock nuts I I9 will draw the blade bartowards the bottom surfaces H4 of the heads II 3, with the blade -I 28 clamped therebetween.
To insure assembly of the blade bar I21 in the correct position with respect, to-the pair of heads H3, the blade bar is provided with a pair of upwardly-projecting-pins I32, adapted "to be received in mating recesses I33 in the bottom surfaces I Id of the heads II 3. The longitudinal spacing and positioning of the pins I32 0n the blade bar I21 corresponds to that of the guide pins 23, with the result that-the pins I32 'do not interfere in any way with the-blade I28, as they extend freely through the notches I29 of the latter.
Adjustment for varying the thickness of rafts (Figs. 8, 9, 10 and 16) It is preferred that variations in the thickness of the grafts out be obtained by the use of shims I34, Fig; 16, positioned between the blade and the heads I E3, the shims being provided with notches I35 receiving the guide pins I23, (Figs. 3 and 13). Each dermatome is equipped with a set of pairs of shims of varying thicknesses, which may be used in single pairs or in various combinations of pairs to obtain any desired spacing 'of-the blade cutting edge I36 with respect to the dermatome convex surface 8i.
Use of post adjustment mechanism (Figs. 6, 7, 8 and-11) The adjustment obtainable with the adjustment bodies 94-438, the adjustment bushings I02 and knobs 505, and the threaded armsIIZ is intended primarily for accurately aligning the cutting edge I 36 of the blade I28 relative to the dermatomeconvex surface 8I. Such adjustment may be found necessary when applying a new blade or when a used blade has been resharpened.
Preferably, the adjustmentv knobs I05, are turned in Whichever direction is-necessary to space the cutting edge of the blade fromthe convex surface of the dermatome, an. arbitrary distanceof four thousandths of an inch. The adjustment mechanism is-held in the desired position by a wedging lock pin I31, provided with a concavity I38 in one edge thereof, the cavity I38 receiving the side of the adjustment bushing I62, (Figs. 6, '7; 8and 11). The loclnng pin I3! is urged axially by a finger nut I39 threadedon the projecting terminal portion ldI-thereof. Further locking of the adjustment mechanism is obtained by turning the lock nut I42 upwardly on the-threaded arm I I2,- until the-nut tightly engages the lower end of the adjustment bushing Hi2.
Use of the graft-thickness varying mechanism (Figs. 8, 9, 1 and 16) Once the above-described adjustment has been made for a particular blade, the adjustment is not changed until the blade has been resharpened or rehoned, or a new blade is used. To vary the thickness of grafts out, it is only necessary to insert the desired thickness of shims between the blade and each head l I 3. For examplaif a graft of ten thousandths of an inch thickness is desired, the operator or nurse preparing the instrument will add to the four thousandths clearance in the original adjustment by inserting shims totaling six thousandths between the blade and each of the heads H3.
The outting-motion-imparting handle Figs. 6 and 7) The post 98 is provided, at the side thereof away from the drum or body member IS, with a handle M3, secured thereto in any suitable manner, for example, as by soldering or brazing, at Md. Preferably, the handle includes a depending portion I 35 around which two or three of the operators fingers may be placed for pulling the blade and its carrying mechanism, and an upwardly-projecting portion I46, against which the operator's thumb may bear for pushing the blade and its carrying mechanism. It should be noted that the thumb rest portion I46 extends upwardly at least as high asthe top of the adjustment knob N35 to form a guard therefor, preventing accidental turning or misadjustment of the knob H95 by pressure of the operators thumb thereon, were the guard not provided.
Front clamping mechanism (Figs. 12 to 15, inc.)
Reference is now made to sheet three of the drawings, particularly to Figs- 12 to 15, inclusive, for a description of the preferred mechanism for holding the graft-transfer member 40 taut against the convex working face SI of the dermatome.
t the front, or right-hand end of the convex surface 3!, as viewed inv Figs. 12 to 15, inclusive, there is provided a fixed clamping block I50, extending between the side walls ll-I8. The block has terminal portions, each of two diameters l5I and i522, the larger diameter portions I5I extending through mating openings I53 in the side walls and the smaller portions [52 projecting therebeyond and through washers 154, to which they are connected in a suitable manner, as be peaning, at I55.
A clamping bar 56 extends between the side walls 'l'-i8 in parallel relation to the clamping block E53, and is mounted for limited pivotal movement on a pin I51 extending through aligned openings I53 in a pair of cars fill-460, formed integral with, and projecting rearwardly from, the clamping bar I56 near its ends, (Figs. 12 and 13). This pin I51 has its terminal portions IGI fixedly secured in the side walls ll-18, and is so disposed with respect to the clamping block l50 that when the clamping bar I56 is moved in a counterclockwise direction, as viewed in Figs. 13 and 15, its clamping face I62 engages the cooperating clamping face "$3 of the clamping block I59. Preferably, the clamping faces [82 and H53 are serrated or toothed, as at 16k, to provide for positive gripping of the attaching portion 3 at the forward end of the graft-transfer member 40 if) when the same is inserted in the clamping mechanism.
To facilitate movement of the clamping bar I56 to and from operative position, the ear I59 is provided with an extension or lever I85 adapted for manipulation by a finger of the operator. Once the graft-receiving member 4a is drawn taut with both ends secured, the clamping bar I 56 will be wedged in clamping position, but with only the forward end of the graft-transfer mem-' ber secured, and no pull applied thereto, the clamping bar might be accidentally moved from clamping position. To avoid this possibility, the extension or lever I65 is provided with a locking member or latch I56, pivoted at one end to the end of the lever I55 and adapted to swing between a locking position where it overlies the lever I65 (Fig. 12), and a releasing position (Fig. 14). When in looking position, the edge IBI of the latch is received beneath the latching pin. IE8, extending inwardly from the wall TI. When the latch is in releasing position, the lever I65 may be moved upward to separate the clamping faces I62-I63. In order that the lever may clear the latching pin I88 during such movement, it is provided with a clearance notch or groove I69 in its outer edge. Preferably, the latch IE6 is provided with an upwardly-directed flange I'II to facilitate movement thereof, by the operator, from looking position.
Rear holding and tightening ratchet mechanism (Fig.9.13, 17,18, 19, 20 and 21) Means are provided adjacent the rear, or left end as viewed in Figs. 12 and 13-, of the dermatome convex surface BI for holding the rear end of the graft-transfer member fill and for tightening the intermediate portion A thereof against said convex surface.
A ratchet shaft I15 extends between the dermatome side walls IT-'13, in parallel relation to the rear edge I16 of the convex wall 19, and at a considerable distance below the same, One end of the ratchet shaft H5 carries a stub journal ITI rotatably mounted in a flanged bushing H3, pressed into a countersunk opening I19 in the side wall I8, (Fig. 18). The opposite end of the ratchet shaftis provided with a stub journal NH, rotatably mounted in a flanged bushing I82 d isposed in a countersunk opening I83 in the side wall ll. The stub journal I8I has its terminal portion I81 extending a material distance beyond the side wall IT. The periphery of the terminal portion I84 is provided with an annular series of ratchet teeth I85, for a purpose to be explained later.
The ratchet terminal portion I84 has an axial bore I86, and a pin is! eXterlds diametrically thereof for engagement by the spaced jaws I88 of a wrench I39 (Fig. 21). The wrench jaws I88 are formed at the endof a nose portion. ISL which is of a diameter permitting its ready insertion in the axial bore I26 of the ratchet terminal portion 84, with the pin 18? between the jaws I8 8. It will be apparent that rotation of the wrench I89 will correspondingly rotate the ratchet shalt I15. Preferably, the cylindrical body of the wrench is knurled, as at IE3, for easy gripping by the operator. Also, the cylindrical body is provided with diametrically-opposed flat portions file to prevent rolling thereof when laid on a flat surface, such as a table top.
A ratchet plate I is secured to the outer surface of the side wa11 H by screws Hi8, the plate we having an opening to? therethrough for unrestricted passage of the ratchet terminal portion I84. The toothed portion of said ratchet terminal is of such length that a, material part thereof projects beyond the ratchet plate I for engagement by a pawl I98, pivotally mounted. on the ratchet plate I05 by the pin I99. The pawl I98 is biased to engagement with the ratchet teeth I35 by a wire spring 20I formed with a loop 252 at one end by which it is mounted on the ratchet plate byone of the screws I96, which passes through said loop. The other end 203 of the spring 20I is loosely received in an opening 204 extending through the handle 205 of the pawl I93, with the springend 203 bearing against one wall of said opening.
The ratchet shaft I15 is slotted, as at 206, for substantially the entire distance between the dermatome side walls 11-18, for reception of the rear end of the graft-transfer member 40 (Figs. 18, 19 and 20).
Cam-tightening mechanism (Figs. 12, 13 and 17 to 20, inc.)
A cam shaft 2) is positioned between, and in parallel relation to, the rear edge I16 of the convex wall 19 and the ratchet shaft I15, with one terminal portion 2 thereof rotatably journaled in the flanged bushing 2I2 which is pressed into the countersunk opening 2I3 of the side wall 18. The other terminal portion 2M is rotatably journaled in a bushing 2I5, formed integral with the ratchet plate I95 and closely received in the Opening 2I6 in the side wall 11. This terminal portion 2M is of sufiicient length to project beyond the ratchet plate, and the projecting part is provided with a series of ratchet teeth 2I1 which preferably extend through a limited portion only of the periphery of the terminal 2M, for a purpose to be hereinafter explained.
The cam shaft terminal portion has an axial bore 2I8, provided with a pin 2I9 extending diametrically thereof, the bore 2I-8 and pin 2I9 corresponding in structure and function to the bore I86 and pin I81 of the ratchet shaft I15, with the result that the same wrench I89 serves to rotate both the ratchet shaft and the cam shaft.
A pawl 22I is urged into contact with the ratchet teeth 2I1 of the cam shaft by the same spring 20I which exerts a biasing effect on the previously-described pawl I98. The pawl 22I is pivotally mounted on the ratchet plate I95 by a pin 222, with a pair of spaced bearing portions 223 and 224 contacting an intermediate section of the wire spring 20I (Fig. 17)
The cam shaft periphery 225 is eccentric relative to the journals thereof, with the resultthat as the shaft is rotated, the line 226 on the periphery 225 which is farthest from the center of rotation 221, moves in the path indicated by the dotted line C, in Fig. 17.
Operation of ratchet and cam securing and tightening mechanism (Figs. 17 to 21, inc.)
After the forward end of the graft-transfer member 40 has been secured by the clamping mechanism at the front of the dermatome, the rearward end of the transfer member is brought around the outside of the convex surface 8|, and over the rear edge I16 of the convex wall 19 and the cam shaft 2I0. The free rear end of the transfer member is directed upwardly through the slot 206 in the ratchet shaft I15, with a terminal portion 226 extending therebeyond (Fig. 19), and adapted to be doubled back and overlapped when the ratchet shaft is rotated by the 12 wrench (Fig. 20). While the ratchet shaft is being turned to draw the graft-transfer member taut, the cam shaft ZID is in its inactive position, as shown in Fig. 19.
Inasmuch as it might be difficult for non-mechanically-minded operators to accurately determine by eye when the cam shaft is in its inactive position, the series of ratchet teeth 2I1 thereof is interrupted by a smooth portion 221. Before the graft-transfer member is inserted in the slot of the ratchet shaft, the wrench is applied to the cam shaft and the latter rotated until the smooth portion 221 passes beneath the pawl 22I and the latter engages the first tooth 2I1. This action will result in a quiet turning of the cam shaft, followed by a click as the pawl drops into the notch beside the first tooth, this first click indieating to the operator that the cam is in inactive position. This signal will be discernible to the operator both by ear and by feel.
ing action of the shaft is limited to increments I corresponding to the angular movement between adjacentr teeth on the ratchet shaft. For example, if a tightening action corresponding to five and a half teeth was required, there would be no way to hold the last half-tooth of motion.
This final tightening, corresponding to a fraction of a tooth on the ratchet shaft, is obtained by rotation of the cam shaft from inactive position towards a position of maximum action or eccentricity, i. e. from the position of Fig. 19 to that of Fig. 20. Any additional tightening obtained by rotation of the cam shaft is retained by engagement of the pawl 22I with the teeth 2I1. It will be noted that not only are the teeth of the cam shaft closer pitched than those of the ratchet shaft, but a full half-turn of the cam from minimum to maximum eccentricity produces much less total movement of the graft-transfer member than a full turn of the ratchet shaft. Therefore, tightening action over several teeth on the cam shaft is required to equal that of one tooth on the ratchet shaft.
Release of raft-transfer member (Figs. 12 to 15 and 17) When the graft-cutting operation has been completed, and it is desired to remove the grafttransfer member 40 from the dermatome, the front end of the transfer member is released by swinging the latch I66 from the locking position of Fig. 12 to the released position of Fig. 14, then lifting the lever I65 from its position, as shown in Fig. 14, to that shown in Fig. 15, whereupon the forward end of the transfer member will slip from between the clamping block and clamping bar due to the tension it was under prior to release.
The rearward end of the transfer member is released simply by pulling thereon lightly, while pressing on the handle 205 of the pawl I98 to disengage the latter from the teeth I of the ratchet shaft, the shaft rotating until the transfer member is unwound therefrom and slips out of the slot 205.
Relieved edges of drum confvem surface (Figs. 6, 7, 12 and 14) Where the outer convex surface of the drum or body member extends for the full width of the body member, as in the construction illustrated in Figs, 1 and 2, there will be edge portions of said surface which will not be covered by the.
graft-transfer member, as the width of the latter is limited to slightly less than the spacing of the inner surfaces of the side walls. In cutting a graft, the adhesive or cement which is applied to the patients donor area skin, may adhere to the exposed edge portions of the convex surface, in which event the blade will cut a graft including the areas of the exposed edge portions, and the corresponding edge portions of the graft so cut will be so much thicker than the rest of the graft as to constitute beads, the blade cutting below the patients skin and into the fatty tissue.
To avoid this danger, the dermatome of Figs. 6 to 21, inclusive, has the side edges of its convex surface 8| cut away, or relieved, as at 230, so that the remaining convexed surface is of a width only slightly greater than that of the grafttransfer member 29 (preferably, about onethirty-second of an inch greater).
. Meaisuring indicia (Figs. 13 and 15) It is preferred that a dermatome for cutting grafts from adults have a. convex surface approximately four inches wide and eight inches long, so that a graft of thirty-two square inches may be obtained at one cutting. Frequently, a cut of less than thirty-two square inches is desired, and difficulty may be encountered in determining accurately how far around the drum to cut to obtain the desired area. The present invention meets this difiiculty by providing, at the semicylindrical edge of one or both of the side plates l1 and 18, a series of graduations or indicia 233, preferably expressed in inches and fractions thereof, and starting at the front, or right-hand edge, as viewed in Figs. 13 and 15.
Narrow drum dermatome (Figs. 22 and 23) While, as previously indicated, a drum having an effective width of approximately four inches is preferred for use with adult patients, in the case of children and some types of adult work a narrower drum is preferable due to limited donor areas available. A drum having an effective width of two and a half inches is desirable in many instances. However, it has heretofore been thought that a drum of less than four inches width was impractical, due to the space necessary between the drum side walls for the operators fingers in gripping the handle of the dermatome.
In Figs. '22 and 23 there is illustrated a dermatome whose drum has an efiective width of only about two and a half inches, yet which provides ample space for the operators fingers. This dermatome is identical to that previously described in connection with Figs. 6 to 21, inclusive, except for the drum 258 and the l ngth of the shaft 86. l
The drum or body member 255 comprises a central web 25-1, preferably cast integral with the convex wall 252, the handle core 253 and the pair of low side walls 25 and 255. The handle core 253 is axially bored, as at 256, and counterbored at each end, as at 251, for reception of hardened steel bushings 258 in which the shaft 86" slides and rotates. Knurled sleeves 258 are pressed on the handle core 253 from opposite ends thereof, and abut the upper edge of the central web 25!. As indicated in Fig. 23, the central web extends for onl about the central third of the front-to-rear overall dimension of the drum, as viewed in Fig. 23, with the result that there is no interference with the transversely-extending clamping block and bar, and with the ratchet and cam shafts.
Preferably, the central web 25! is provided with flanges 263 at its front and rear edges, which flanges are integral with the convex wall 252 and extend laterally a short distance from the central web 25, to further stiffen the latter.
The inner edges 25 9 f the side walls 254 and 255 are spaced radially from the handle a distance amply sufficient for the operators fingers when the handle. 259 is gripped.
Preferably, all of the modifications of dermatomes herein .shown and described are provided with aligned openings in the side walls near the convex wall and substantially midway of the length of the latter, as at 55 in Figs. 1 and2, at 89 in Figs. 6 to 21, inclusive, and at 2M in Figs. 22 and 23. These openings are used in positioning the dermatomes on stands or supports during adjustment of the various mechanisms, both prior to, and following, the cutting of grafts. If desired, these openings may be provided with bushings, as at 90 in Figs. 6 to 21, inclusive, and at .252 in Figs. 22 and 23.
In the preferred embodiments, the drums or body members are made of cast brass, and all the remaining parts which are permanently associated therewith are manufactured of stainless steel. The combination of these two metals has the advantage that their coefficients of expansion are so nearly alike that no binding, misalignment or warping of associated parts occurs when the instrument is subjected to the relatively high temperatures encountered when sterilizing the same.
While the invention has been shown in several forms, it will be understood that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.
This application is a continuation-impart of applioants copending application for Skin grafting method and apparatus, Serial No. 583,983, filed March 21, 1945.
What is claimed is:
l. .A dermatome including :a body member comprising a pair of approximately semi-cylindrical spaced parallel side walls joined along their convex edges by a curved bottom wall having a convex outer surface, and means for supporting a graft-cutting blade from said body member for cutting movements in parallel relation to the convex outer surface, the width of said convex surface being approximately the same as the space between said side walls.
'2. A dermatome includinga body member comprising a pair of spaced parallel side walls joined by a curved bottom wall having a convex outer surface, and means adapted to support a graftcutting blade from said body member for cutting movement parallel to said convex outer surface, said curved bottom wall having its convex outer surface at its side edges relieved an amount approximately equal to the thickness of the side walls.
3. A dermatome comprising a body member including a pair of semi-cylindrical side walls disposed in parallel spaced-apart relation and a bottom wall joining said side walls at their convex edges and having a convex outer surface; means adapted to support a graft-cutting blade from the body member for cutting movement parallel to said convex outer surface, and means for retaining a graft-transfer member against said convex outer surface with a portion of said transfer member disposed between said spaced side walls, the effective width of said convex outer surface corresponding approximately to the spacing of said side walls.
4. A dermatome comprising a body member having a convex outer surface, means adapted to support a graft-cutting blade from said body member for cutting movement parallel to said convex outer surface, means for securing one end of a flexible graft-transfer member to the dermatome, means for securing the other end of graft-transfer member to the dermatome with the intermediate portion of said transfer member against said convex outer surface and for pulling said transfer member in increments to tighten said intermediate portion, and cam means for tightening said transfer member a portion of one of said increments.
5. In a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut, means carried by the body member and adapted to hold one end of the graft-transfer member, means adustable in predetermined increments and adapted to tighten and hold the other end of said graft-transfer member with the intermediate portion of said transfer member engaging the convex surface of the body member, and means for further tightening said transfer member in fractions of said predetermined increments.
6. In a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut, means for holding each end of said transfer member to the body member, the means for holding one of said ends comprising a pair of clamping members, one of which is movable toward and away from the other into and out of clamping relation, and means by which such movement may be imparted to the movable clamping member.
7. Structure as specified in claim 6, including means for releasably locking the clamping members in clamping relation.
8. In a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut; a first means for holding one end of said grafttransfer member to said body member; and a second means for holding the other end of said graft-transfer member to said body member, said second means comprising a rotatable shaft, means for securing said other end of the rafttransfer member thereto, and means for applying rotary motion to said shaft to draw said graft-transfer member taut against said body member convex surface.
9. Structure as specified in claim 8, including means for retaining saidshaft in rotated position with the graft-transfer member drawn taut thereby.
10. In a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut; first means carried by the body member for holding one end of said graft-transfer member thereto; a shaft rotatably journaled on said body member; means for securing the other end of said graft-transfer member to said shaft with the intermediate portion of said transfer member disposed against said body member convex surface; and means for transmitting rotary motion to said shaft, whereby said graft-transfer 16 member is drawn taut against said convex surface.
11. Structure as specified in claim 10, including cooperating ratchet and pawl mechanisms associated with said shaft and body member for retaining said shaft in rotated position with the graft-transfer member held taut.
12. In a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut; clamping means carried by the body member for securing one end of the graft-transfer member thereto; a shaft rotatably supported by said body member; means for securing the other end of said graft-transfer member to said shaft with the intermediate portion of said graft-transfer member positioned against said body member convex surface; a ratchet carried by said shaft; a pawl having a stationary pivotal support relative to said body member and adapted to cooperate with said ratchet to retain said shaft in rotated position with said graft-transfer member taut; and a second shaft eccentrically journaled in said body member and adapted, when rotated, to bear with gradually-increasing pressure against an unsupported portion of the grafttransfer member intermediateits points of securement by the clamping means and the firstmentioned shaft.
13. In a dermatome including a body member having a convex surface against which a flexible graft-transfer member is adapted to be held taut; first and second securing devices carried by said body member for fastening opposite terminal portions of the graft-transfer member to the body member, one of said securing devices including mean-s for drawing said graft-transfer member taut against the body member convex surface.
14. Structure as specified in claim 13, including means adapted to engage the graft-transfer member intermediate its secured terminal portions, said means being adjustable to increase the tautness of said graft-transfer member beyond Q that provided by the tautness-producing means of said one of the securing devices.
15. A dermatome comprisin a body member having a pair of side walls joined at one edge by a curved bottom wall having a convex outer surface, bearing structure carried by said pair of side walls, a shaft journaled in said bearing structure for rotary and reciprocatory movement relative to said body member about and along an axis coinciding with the axis of generation of the convex outer surface, a pair of posts carried by the terminal portions of said shaft and extending radially of the latter in parallel relation at opposite sides of the body member, a head at the outer free end of each of said posts, blade-supporting means carried by said heads and bridging the space therebetween, means for adjusting said blade-supporting means toward and away from the heads, and means for adjusting said heads toward and away from the shaft.
16. A dermatome comprising a body member having a convex outer surface, bearing structure carried by said body member, a shaft journaled in said bearing structure for rotary and reciprocatory movement therein relative to said body member about and along an axis coincidingwith the axis of generation of the body member convex outer surface, a frame carried by said shaft and including a member adapted to support a blade with its cutting edge in close proximity to said convex outer surface, first adjusting means 17 for obtaining parallelism between the cutting edge of a blade supported by said frame and said convex outer surface, and secondadjusting means for varying the spacing f said blade-cutting edge with respect to said convex outer surface.
1'7. A dermatome comprisin a body member having a convex outer surface; bearing structure carried by said body member; a shaft journaled in said bearing structure for rotary and reciprocatory movement; a frame carried by said shaft and including a, pair of spaced, parallel posts at opposite sides of the body member and a blade-supporting member carried by the free outer ends of said posts and adapted for movement parallel to and at a predetermined distance from said convex outer surface, each of said posts including a threaded arm, a rotatable adjusting sleeve threaded on said arm, means for preventing rotation of said arm during rotation of said adjusting sleeve, whereby rotation of said adjusting sleeve will vary the effective length of the post, and a head carried by said arm and to which the blade-supporting member is secured, and means carried by each of said heads for securing said blade-supporting member thereto, said last-mentioned means urging the blade-supporting member towards the heads to clamp a blade between said member and said heads, whereby the predetermined spacing of said bladesupporting member with respect to the convex outer surface may be accurately varied by the insertion of shims of the desired thickness between the blade and the heads.
18. For use in a dermatome having a pair of shafts provided with ratchet teeth; a pawl assembiy comprising a supporting plate having a pair of openings therethrough for free passage of the ratchet-toothed portions of said pair of shafts, a pair of pawls pivotally mounted on said supporting plate in position to engage the shaft ratchet teeth when said shaft toothed portions extend through said openings, and a spring mounted on said supporting plate for tensioned engagement with both of said pawls and adapted to urge the latter into mating relation with the shaft ratchet teeth.
19. Apparatus of the character described comprising a body member having a convex surface; a shaft supported by said body member for rotary and reciprocatory movement relative thereto; a pair of posts carried by the terminal portions of said shaft at opposite sides of the body member and in parallel relation; means for adjusting the length of each post radially of the shaft, said means including an adjusting knob at the upper end of each post; means supporting a blade from the lower ends of the pair of posts with the Cutting edge thereof disposed in close proximity, and parallel to, the convex surface of the body member; and a handle carried by one of said posts and adapted to be gripped by the operator of the apparatus to impart the desired rotary and reciprocatory motion to the shaft, posts and blade relative to the body member and its convex surface, said handle including a first portion adapted to be engaged by the operator's fingers and a second portion adapted to be engaged by the operators thumb, said second portion being disposed between the adjusting knob and the operators thumb when the handle is gripped, whereby accidental turning of said adjusting knob by contact with the operators thumb, is prevented.
20. In a dermatome; a body member comprising a curved wall of uniform width having a convex outer surface; a pair of side wallsextending from the side edges of said curved wall radially inward relative tothe axis of generation of said convex outer surface; a centraiwan parallel to, and substantially midway of, said side walls and extending radially-inward. from the inner surface of the curved wall a material distance beyond said axis of generation of the convex outer surface; a handle carried by said central wall and extending transversely relative to said central and side walls and being spaced radially from the inner edges of the latter: a shaft journaled in said handle for rotary and reciprocatory motion relative to said body member, the longitudinal axis of said shaft coinciding with said axis of generation of the convex outer surface; and means for supporting a blade from said shaft with its cutting edge adjacent and parallel to said convex outer surface.
21.- In a dermatome; a body member comprising a curved bottom wall having a convex outer surface and parallel side edges, a central wall extending upwardly from the bottom wall substantially midway of, and parallel to, the side edges of the curved bottom wall, and a handle carried by said central wall; a shaft journaled in said handle for rotary and reciprocatory movement relative to said body member; and means carried by said shaft for supporting a blade with its cutting edges adjacent and parallel to said convex outer surface.
22. Structure as specified in claim 21, including laterally-extending webs connecting the central wall and the curved bottom wall and bracing the former relative to the latter.
23. In a dermatome; a body member comprising a curved bottom wall having a convex outer surface against which a flexible graft-transfer member is adapted to be held, a pair of parallel side walls extending upwardly from the side edges of said bottom wall towards the axis of generation of said convex outer surface, a central wall parallel to, and midway of, said pair of side walls, and a handle carried by said central wall and extending transversely thereof; a. shaft journaled in said handle for rotary and reciprocatory movement relative to the body member, the axis of rotation of said shaftcoinciding with the axis of generation of said convex outer surface; and said handle being spaced radially from the upper edge of said side walls; means carried by said shaft for supporting a blade with its cutting edge parallel to, and spaced slightly from, said convex outer surface; first graft-transfer member securing means carried by said side walls and bridging the space therebetween near one end of the curved bottom wall; and second grafttransfer member securing means carried by said side walls and bridging the space therebetween near the other end of said curved bottom wall. said central wall terminating short of said first and second securing means.
24. The method of transferring a skin graft from a donor area to an injured area which comprises; temporarily retaining a flexible, adhesive-coated graft-transfer member taut against a convex surface with the adhesive coating exposed; rolling the convex surface, with the grafttransfer member taut thereon, over the donor area, thereby causing the skin of the donor area progressively to adhere to said. graft-transfer member through the action of said adhesive coating, said rolling action thereby lifting said skin; cutting the lifted skin simultaneously with the rolling action, while maintaining the line of sev- ,erance a predetermined distance from the grafttransfer member; removing the graft-transfer member, with the graft thereon, from the convex surface; positioning the graft on the injured area without removing it from the graft-transfer member; and retaining the graft in position by means of the graft-transfer member.
25. In a dermatome, the combination of a body member having a working face, means for supporting a cutting member for cutting movement parallel to said working face and at a predetermined distance therefrom, and means for mechanically securing taut against said working face a flexible graft-receiving member.
26. In a dermatome, the combination of a body member having a. convex working face, means adapted to support a knife for cutting movement parallel to said working face and at a predeterhaving a convex working face; a pair of parallel,
spaced-apart posts at opposite sides of the body member and extending radially with respect to said convex face; a blade-supporting bar carried by the posts at one end of the latter and bridging the space therebetween; means pivotally and slidably supporting the posts at their other ends from the body member for movement of the bar' parallel to, and at a predetermined distance from the convex face; and means for mechanically retaining a flexible graft-transfer member against the convex working face of the body member.
28. A dermatome comprising a body member having a convex working surface rockable on a patients body; means for securing a flexible graft transfer member, having an adhesive facing, taut against the convex surface, whereby rocking of said body member will progressively lift an area of skin by adhesion of the latter to the taut graft-transfer member; and means for supporting a knife a predetermined distance from the convex surface for cutting movement to that it may progressively cut a graft of the skin as the latter is lifted.
29. A dermatome comprising a body member having a convex surface; means for mechanically temporarily retaining a flexible graft-transfer member, having an adhesive skin-engaging surface, on said convex surface; and means for supporting a graft-cutting member a. predetermined distance from the convex surface for cutting movement parallel thereto.
JOHN D. REESE.
REFERENCES CITED UNITED STATES PATENTS Name Date Reese Dec. 26, 1944 Number
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US618523A US2442434A (en) | 1945-09-25 | 1945-09-25 | Dermatome |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US618523A US2442434A (en) | 1945-09-25 | 1945-09-25 | Dermatome |
Publications (1)
Publication Number | Publication Date |
---|---|
US2442434A true US2442434A (en) | 1948-06-01 |
Family
ID=24478065
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US618523A Expired - Lifetime US2442434A (en) | 1945-09-25 | 1945-09-25 | Dermatome |
Country Status (1)
Country | Link |
---|---|
US (1) | US2442434A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3563120A (en) * | 1969-07-08 | 1971-02-16 | Chepos Z Chemickeho A Potravin | Dermatome |
US10123819B2 (en) | 2015-04-14 | 2018-11-13 | Zimmer Surgical, Inc. | Multi-piece dermatome body |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2366054A (en) * | 1944-08-02 | 1944-12-26 | John D Reese | Dermatome |
-
1945
- 1945-09-25 US US618523A patent/US2442434A/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2366054A (en) * | 1944-08-02 | 1944-12-26 | John D Reese | Dermatome |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3563120A (en) * | 1969-07-08 | 1971-02-16 | Chepos Z Chemickeho A Potravin | Dermatome |
US10123819B2 (en) | 2015-04-14 | 2018-11-13 | Zimmer Surgical, Inc. | Multi-piece dermatome body |
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