CA2250408A1 - Disposable curette and method of manufacturing the same - Google Patents

Abstract

A disposable, loop-form surgical curette blade formed as an integral unit from a single elongated blank so as to have the loop-form cutter formed by one sharpened end portion of the blank and a shank formed by the balance of the blank and extending from the loop-form cutter, and a novel method of manufacturing such a blade.

Description

'. CA 02250408 1998-10-13 DISPOSABLE CURETTE AND METHOD OF
MANUFACTURING THE SAME
BACKGROUND OF THE INVENTION
This invention relates to curettes of the type used for such purposes as removal of cancerous and non-cancerous skin growths.
The technique of curettage is routinely used by dermatologists to separate diseased skin or skin lesions from normal skin. The instrument used to perform curettage on the skin is termed a dermal curette. Commonly used dermal curettes include, among others, the Fox curette and the Piffard curette, both of which are manual stainless steel instruments having a loop-form cutter or blade and an elongated handle for manipulation of the blade by the user. These are regarded as permanent, reusable curettes, in that because of their expense, they would not be economical for single-use application.
Disposable curettes are also available and are generally suitable for their intended purpose.
However, they often may have a different feel to the user, and tlierefore may require practice before the user who is accustomed to a reusable curette, such as the Fox or the P~itara, can become proficient in their use. The reason for this is that normal tissue has a different feel under the cutting action of the curette than lesionai tissue. The user who is more sensitive to this difference in feel will also be more proficient at removal of lesions, since the sensitivity to feel will allow more complete removal of lesional tissue with less incursion into normal tissue.
~This son of sensitivity comes with practice and eyerience, and can be disrupted by differences in design, materials and structure, as between different curettes.
Accordingly, practitioners would normally prefer to confine their use of curettes to a single type. The need to choose a single type of curette could. however be obviated by a disposable curette having the same fe~L heft, weight and balance as a reusable curette.

. _ CA 02250408 1998-10-13 Of course, the disposability of a curette is entirely a matter of economics, and any curette may be regarded as disposable if the user is unconcerned about its cost. As a practical matter, I~owever, many physicians, iucludu~~ dcrmatologista for cvan~plc. uac; wrcttca routinely and therefore cannot treat reusable curettes as disposables, nor can they escape the cost trade-o$' between presently available reusable and disposable curettes.
The cost of a reusable curette is relatively high compared to available disposable curettes, and the instrument therefore must serve the user over a relatively long term in order to justify its cost. Typically, after a period of use, the cutting blade of a reusable curette will become dull and must be sent out for resharpening. In addition, there are the costs of time, material, equipment, energy and labor involved in the repeated cleaning and sterilization ofreusable curettes. Still further, a practitioner who sees patients in more than one examination room, or in multiple office locations, will require duplicate sets of such instruments to ensure tliat a set of suitable, freshly sterilized, sharp curettes are always available in each examination room or office location while others are being sterilized or sharpened. As may be appreciated, the costs associated with curette procur°ment and maintenance can be s,~bstantial.
Of course, many of the logistical and financial drawbacks attendant to the use of reusable curettes disappear entirely if one instead chooses to use only disposable curettes. However, disposable curettes also have their associated drawbacks.
specifically, presently available disposable curettes are comprised of an inseparable handle and stainless steel blade assembly which is intended to be disposed of entirely after a single use.
Thus, although sharpening, cleaning or sterilization costs do not arise, the full replacement cost of the curette, while much lower than the cost of a reusable curette, must be paid with each use.

Another disadvantage of some disposable curettes is the use of a rather thin gauge material for the loop-form cutting blade. A curette blade formed of such thin gauge material may tend to deform under mechanical pressure and therefore will not have a consistent feel in use.
Thus, an unduly thin gauge curette blade may be more difficult to control and use, regardless of the e,~cperience of the user.
Additionally, presently available disposable curettes may tend to be less sharp than either a new or resharpened reusable curette. This may be due to mechanical limitations encountered in the sharpening ofthe thin gauge blade material.
A final disadvantage ofpresently available disposable curettes is the liglitweiglit plastic handle which does not have the same feel or shape as the stainless steel handle of a reusable curette. No choice ofhandle is available since these disposable curettes are all manufactured wmh the same handle style.
Among the prior art relating to curettes in general are U.S. Patems 2,569, ~;
i, l,o i ;,-t?u, 2,651,068, 4,044,770, 4,785,796, 4,791,924, 4,932,957 and 5,116,;46, as well as British Pateat 1,192,654. Several of these patents disclose curette instruments with a loop-form blade or a non-cutting loop-form working end. Other e~camples ofrelated an include U.S.
Patents 1,089,018, 3,502,082 and 4,414, 974.

BRIEF SUMMARY OF THE INVENTION
The present invention contemplates a disposable curette in the form of a sturdy and sharp curette blade having a loop-form cutter portion and an elongated shank portion by which the disposable blade may be attached to a conventional scalpel blade handle. In order to make this disposable blade of suitable strength and sharpness, and therefore ofcomparable feel to a conventional reusable curette, the material from which it is formed is to be of a sufficient gauge or thickness, as will be described. To offset the additional cost of better material, a specific blade structure is utilized which minimizes the material for each blade, thereby achieving a cost generally in line with that of disposable curettes, which may be neither as sturdy nor as sharp.
An additional factor in this favorable cost comparison is that only the blade is disposed of a$er use, the handle being a conventional handle of the operator's preference, such as commonly used heretofore to hold a disposable scalpel blade. Nlore specifically, the disposable curette blade of the present invention contemplates an elongated blank stamped from surgical grade stainless stee: and formed with au elongated blade or cotter portion ewending adjacent one end ofthe blank and au elongated shank portion extending adjacent the opposed end of the blank. The blade portion is formed into a loop to provide the loop-form cutting blade, and the shank portion e.~ctends therefrom to be received by the blade attachment portion of a conventional scalpel blade handle.
~In several alternative embodiments of the invention, different structures for the loop-form cutting blade are contemplated, but all are intended to provide a curette blade which offers the sharpness, heft or mass, and rigidity, and lience the overall feel of a conventional reusable curette, without nearly the cost of procurement or the cost and inconvenience of cleaning, sterilizing and resharp earn Q.

Accordingly, it is one object of the present invention to provide a novel and improved disposable curette blade, such as a dermal curette, and a novel and improved method of manufacturing such a curette blade.
A further object of the invention is to provide an improved loop-form curette blade formed from an elongated blank having one end portion thereof which forms the Loop-form blade and the opposed ead portion thereof foaming a shank which e~ctends from the loop-form blade.
These other objects and fitrther advantages of the invention will become more readily apparent upon consideration ofthe following detailed description and the accompanying drawings, in which:
FiQ. 1 is a side elevation of a blank from which a disposable curette blade according to the present invention is formed;
Fig. 2 is a side elevation similar to Fig. 1 showing the upper end portion of the blank formed as a loop-form cutter or blade;
Fig. 3 is a rear elevation taken on line III-III of Fig. 2;
Fig. 4 is an enlarged fragmentary portion of the loop-form cutter of Fig. 2;
FiQ. 5 is an enlarged, fragmentary rear view similar to Fig. 3 showing an alternative embodiment of the invention; and FiQ. 6 is an enlarged, fraQmentan~ rear vew similar to Fia. 3 sliowinQ another alternative embodiment of the invention.

_'7_ All disclosure herein relating to the structure and fabrication of my novel curette blade is to be understood as disclosure of both my novel method and structure, even though such disclosure may not be otherwise characterized as method.
There is generally indicated at 10 in Fig. 1 a disposable curette blade according to one presently preferred embodiment of the instant invention, and cornprisurg a single piece or unitary blade structure 12 which is stamped as a blank from a suitable material.
Although blade 12 may be fabricated from either surgical grade carbon or stainless steel, the preferred material is surgical grade stainless steel of the 300 or 400 series. Specifically, the American Society for Testing and Materials has listed stainless steel types for curettes to include types 302, 303, 410, 416 and 420. Of course, otlier materials and material types may be equally suitable for the described blade.
Blade 12, as noted, is comprised of a single elongated cutter portion 14 e.~ctending from one end 24 thereof and an elongated shank portion 16 e~~tending from the opposed end 20 thereof.
As noted, shank 16 may be formed to cooperate with any l.~nown scalpel blade handle, such as a Bard-Parker or Bard-Parker-style handle, or a Beaver or Beaver-style chuck handle. Of course, the shank 16 may be formed for retention by other types of suitable blade handles as well.
The blade shank 16 as shown includes a notched aperture 13 by which the blade is cooperable with a Bard-Parker or Bard-Parker-style liandle, for example one which accepts a # 1 ~
scalpel blade. As is well known, the Bard-Parker or Bard-Parker-style liandle includes a blade attachment portion which would correspond to the aperture 13 in order to receive the shank 16 in a reversible locking engagement whereby the blade 10 is retained and secured in place with respect to the Bard-Parker or Bard-Parker-style blade handle.
In one alternative configuration for sham: 16, not shown herein, the shank 16 may be formed without a notched aperture, such shank conforming to the slotted blade opening of a Beaver or Beaver-style chuck collet. Wlien the chuck collet is attached to the Beaver or Beaver-style handle by threaded engagement therewith and screwed on to the handle, the resulting clamping action securely retains the blade shank 16. This self locking collet mechanism is well known.
In another alternative configuration for sham: 16, not shown herein, the shank 16 may be formed without a notched aperture, but to include a small circular opening in the middle ofthe sham: near end 20, whicli conforms with a corresponding projection on the slotted blade opening of a Beaver Lok-Collet chuck. When the Lok-Collet chuck is attached to the Beaver handle by threaded engagement therewith and screwed on to the liandle, the resulting clamping action securely retains the blade shank 16. This self locking collet meclianism is also well known.
Furtlier description of the liandle structures discussed hereinabove, or other conventional handle structures for use with blade 10, is believed to be unnecessary for an understanding of the present invention. Sui~ce it to note in this regard that whatever the handle structure contemplated, the shank 16 which is formed to cooperate with sucli a liandle is comprised of a single elongated portion of the curette blade body 13 extending from one longitudinal end, for example longitudinal end 20 ofthe body 13.
The ideal thiclmess of the material from wliich the disposable curette blade can be made is airectly dependent upon the style of handle used to cooperate with the blade.
An ideal matetzal, and hence blade thickness of 0.01 ~ inches is compatible with the Bard-Parker and Bard-Parker-w CA 02250408 1998-10-13 style handles. An ideal material, and hence blade thicimess of 0.025 inches is compatible with the Beaver and Beaver-style chuck handles. Since it to say, the thickness of the material from which the disposable curette can be made is dependent upon structural features inherent in the cooperable handle.
Cutter portion 14 is an elougated portion extending from a juncture 22 with shank portion 16 to the opposed end 24 of blade body member 13. The cutter portion 14 is preferably of uniform width and thickness and includes a sharpened edge 26 extending essentially throughout the length thereof The sharpened edge can be provided by performing suitable grinding on thereof either prior to formation of the cutter portion 14 into its final loop-like form, or after cutter portion 14 is formed into its final bodily shape.
Referring more specifically to Figs. 2 and 3, the cutter portion 14 is formed by bending thereof into a loop-form cutter 28, which may be either circular or elliptical, for example. In addition, the loop-form or shape of cutter portion 14, which is achieved by bending the cutter portion 14 back upon itself may produce a shape whicli is either generally cylindrical or generally conical, although, of course, it will be appreciated that to produce a conical shape, the cutter portion 14 (as shown in Fig. 1) would have to extend along an arc rather than as a straight extension. Alternatively, a conical shape can be produced by bending the cutter portion 14 back upon itself in~ such a manner that the upper and lower portions of cutter portion 14 are bent into unequal circular or elliptical loops.
As noted, the loop-form cutter 28 is formed by bending cutter portion 14 around itself so that free end 24 resides adjacent a portion 30 of shank 16 next to jwtcture 22. Accordingly, curette blade 12 is comprised of a single unitary length of blade material having a sliank 16 formed from a sine elongated extent of the blade bodv extending from one end thereof and a loop-form cutter portion formed by a single elongated portion of the blade bodv extendins from -lU-the opposed end thereof. This structural feature is common to all disclosed embodiments of the invention.
As shown in Figs. 2 and 3, one embodiment of the invention contemplates forming the loop-form cutter portion 28 by producing an arcuate bend beginning generally in the vicinity of juncture 22, the bend being of suitable radius to produce a loop of proper dimensions for use as a blade, for example with a cutter diameter ranging from 2 to ~ millimeters. The cutter diameter size may be stamped on the shank of the disposable curette blade to designate the size of the loop-form cutter.
A terminal end portion 32 of cutter portion 14 adjacent longitudinal end 24 is maintained in a straight configuration and a suitable bend 34 forms a juncture between portion 32 and the arcuate curvature of loop-form cutter 28. to thereby allow end portion 32 to reside adjacent the portion 30 of shank 16. A suitable attachment means such as a stainless steel civet 36 is axed in mutually registered openings (not shown) through the portions 30 and 32 to fi~cedly secure these portions together and thereby retain the loop-form shape of cutter portion 23.
Alternatively, for this and other descn'bed embodiments where a fastener such as the rivet 36 is described, the rivet may be substituted by a spot weld or other suitable fastening means.
As noted hereinabove, the sharpened edge 26 may be provided by grinding blade portion 14 either prior to or after forming thereof into the loop-form cutter 23. If the sharpened edge 26 is provided pmor to forming blade portion 1=1 into the loop-form cutter, the preferred material for fabrication is an austenitic stainless steel, for example type 302 or 303.
These non-lieat treatable stainless steels are preferred because if a lieat treatable material were used, the heat treating would preferably be done before the grinding operations, and tlierefore also before forming. This would substantially limit the formability of the material and the material would fracture during the forming process.

w CA 02250408 1998-10-13 If the sharpened edge 26 is provided after forming blade portion 14 into the loop-form cutter, the preferred material for fabrication is a martensitic stainless steel, for example type 410, 416 or 420. These heat treatable stainless steels are preferred since heat treating after forming will result in a stronger blade structure.
In a preferred method, the sharpened edge 26 is provided before loop-form cutter 28 is formed as above described. As shown in Fig. 4, the sharpened edge 26 may be produced by grinding an angle of 7 degrees on the outside aspect ofblade portion 14 as indicated at 38.
Of course, it will be appreciated that the scale of Fig. 4 has been greatly enlarged, even more so than the enlarged scale of Figs. 1 to 3, in order to clearly show the detail of sharpened edge 26. An appreciation for the actual size of the structure shown in Fig. 4 is gained by noting that the overall width W ofportion 2S may be approximately 0.12 inches, for example.
In this preferred form ofproviding a sharpened edge 26 before loop-form cutter 28 is formed, the ground edge may also be placed alternatively on the inside aspect of blade portion 14 or on both the outside and inside aspects of blade portion 14. Placing the ground edge on the outside aspect of blade portion 1-1 is preferred because this results in a somewhat conical shaped loop-form cutter, a shape that resembles the blade portion of a reusable curette.
As noted above, the sharpened edge 26 may alternatively be provided by performing suitable sharpening operations on blade portion 14 after forming thereof into the loop-form cutter 23. The sharpened edge can be provided by grinding an angle of 7 degrees on the outside aspect of the loop-form cutter. This method is less preferred because grinding the uiside, the outside or both the inside and outside aspects of loop-fomn cutter 28 is a difficult operation.

If sharpened edge 26 of blade portion 14 is provided after forming thereof into the loop-form cutter 28, the entire blade structure is preferably heat treated prior to grinding, according to American Society for Testing of Materials published standards for the heat treating of stainless steels for surgical instruments.
Figs. 5 and 6 show alternative embodiments of the invention which are essentially similar to the embodiment above described, but with differences as follows. In Fig. ~, the blade shank 16 includes the portion 30 and a bend generally coinciding with juncture Z2 where the arcuate form of cutter 28 beans. Again, the bend radius of cutter portion 28 is suitable to foam cutter 28 as an essentially closed loop. For the Fig. 5 embodiment however, longitudinal end 24 of cutter portion 14 turns back upon portion 30 and resides adjacent to juncture 22 where the initial bend occurs between sitalk 16 and cutter portion 1~. The longitudinal end 24 may abut shank 16 adjacent juncture 22, or as shown, may be spaced slightly therefrom. With either variation, the loop-form cutter is produced as an essentially complete loop.
Fig. 6 illustrates yet anotlier embodiment of the invention in which shank 16 again includes a portion 30 adjacent the juncture 22 where m uiitial bend is Loaned between shank 16 and cutter portion 14. Cutter portion 14 is formed, as in other described embodiments, by bending thereof into an arcuate form to provide the loop-form cutter 28. However, in the Fig.
6 embodiment, the longitudinal end 24 extends back upon that part of cutter portion 14 adjacent to juncture 22 and is formed to nest within the initial arcuate curvature 42 of loop-form cutter 28.
The cutter end 24 may be retained with respect to the adjacent part of cutter portion 1=t as by a suitable stainless steel rivet 36 passed tlirou5h suitable, mutually registered apccturc~ (uut ahown), ur alternatively by spot welding.
A sharpened edge for the embodiments of Figs. ~ and 6 may be provided in essentially the same manner as described above for other embodiments. Grinding may be performed either prior _i;_ to or after formation of the loop-form cutter 28, but tliis operation is preferably performed prior to formation of the loop-form cutter for the same reason as described for previous embodiments.
A preferred method of manufacturing the curette blade structure, as described with reference to any embodiment is as follows: first, stamp the single elongated black; second, surface grind a sharp cutting edge on blade portion 14; third, press form the loop-form cutter 28; and last, retain the loop-form cutter shape by fastening free end 24 to portion 30 of shank 16. As will be appreciated from the above description, the manufacturing method may also include suitable heat treating as specified, and may exclude the fastening of free end 24 as in the Fig. 5 embodiment.
According to the description hereinabove, the present invention contemplates a novel and improved disposable, single use curette blade o$'erin~ the benefits of minimal cost achieved through minimal material requirements and simplified mechanical fabrication.
but having the feel of a reusable curette.
Of course, I have envisioned certain modified and alternative embodiments of the invention, and surely such would also occur to others versed in this art once tliey were apprised of my invention. For example, although the loop-form cutter is shown as being symmetrical about the plane of the blade body, it may alternatively be formed asymmetrically with respect to the plane of the blade body. Further, as noted above, the loop-fornr cutter may be of alternative forms such as elliptical or conical, or a combination of these geometries. Still further, the sharpened edge may extend through all or only a part of the 360 degree e.~ctent of the loop-form cutter, and may be either symmetrically or asymmetrically positioned witli respect to the plane of the blade body, althougli preferably the sharpened edge will extend substantially throughout the 360 degree e~ctent of the loop-form cutter, and in a symmetrical structure as above described, substantially throughout the 180 degree extent of the loop-form cutter on either side of the plane of the blade body. Accordingly, it is my intention that the invention should be construed broadly and limited -1~-only by the scope of the claims appended hereto.

Claims (15)

1. A curette blade black for use in fabricating a disposable, single use curette blade comprising:
an elongated, unitary body member having integrally formed shank and cutter portions;
said shank portion extending longitudinally from one longitudinal end of said body member and said cutter portion extending longitudinally from the other longitudinal end of said body member to adjoin said shank portion;
said shank portion being adapted for cooperation with a conventional scalpel blade handle for selectively releasable retention of said curette blade with respect to such a scalpel blade handle; and said cutter portion being adapted to be formed into an arcuate cutter and having at least one edge portion adapted to be sharpened to provide an arcuate cutting edge of said arcuate cutter.

2. A disposable, single use curette blade comprising:
An elongated, unitary body member haying integrally formed shank and cutter portions:
said shank portion extending longitudinally from one longitudinal end of said body member and said cutter portion extending longitudinally from the other longitudinal end of said member to adjoin said shank portion at a juncture therebetween;

said shank portion including means for cooperation with a conventional scalpel blade handle to selectively, releasably retain said curette blade with respect to such a scalpel blade handle;
said cutter portion having at least on edge which is sharpened to form a sharp cutting edge; and said cutter portion being formed as a generally arcuate cutter to provide said one edge as an arcuate edge portion.

3. The curette blade as set forth in Claim 2 wherein said arcuate cutter is a loop-form cutter.

4. The curette blade as set forth in Claim 3 wherein said arcuate cutter is formed essentially as a complete loop to provide said loop-form cutter.

5. The curette blade as set forth in Claim 4 wherein said complete loop is formed by said cutter portion extending arcuately at a radius selected to bring said other longitudinal end of said body member to a position adjacent said juncture between said shank portion and said cutter portion.

6. The curette blade as set forth in Claim 5 additionally including fastening means for securing said oilier longitudinal end of said body member adjacent said juncture.

7. The curette blade as set forth in Claim 5 wherein said sharp cutting edge extends over approximately a 360 degree extent of said arcuate edge portion.

8. The curette blade as set forth in Claim 5 wherein said body member is of a generally flat, thin section configuration extending on a plane and said loop-form cutter is generally symmetrical about said plane.

9. The curette blade as set forth in Claim 8 wherein said sharp cutting edge extends over approximately a 180 degree extent of said complete loop on either side of said plane.

10. The curette blade as set forth in Claim 5 wherein said complete loop is of a generally circular form.

11. The curette blade as set forth in Claim 5 wherein said complete loop is of a generally elliptical form.

12. The curette blade as set forth in claim 5 wherein said complete loop is of a generally conical form.

13. A method of fabricating a curette blade comprising the steps of:
forming a unitary curette blade body member from a thin section, metallic material;
providing said body member with an elongated shank portion which extends from one longitudinal end thereof and is adapted for cooperation with a scalpel blade handle to be releasably retained thereby;
providing said body member with an elongated cutter portion which extends from the other longitudinal end thereof to adjoin said shank portion at a juncture therebetween;

sharpening an edge of said cutter portion to form a sharp cutting edge; and forming said elongated cutter portion into a generally arcuate cutter with said sharp cutting edge foaming an arcuate edge portion.

14. The method as set forth in Claim 13 wherein said forming said elongated cutter portion is forming thereof along a radius selected to bring said other longitudinal end of said body member into a position adjacent said juncture to form a loop-form cutter.

15. The method as set forth in Claim 14 including the additional step of mechanically securing said other longitudinal end of said body member adjacent said juncture.