CA1130765A - Arthroscope - Google Patents

Abstract

NOVEL ARTHROSCOPE

Abstract of the Disclosure An arthroscope is constructed within a sheath having a cross-sectional configuration generally rectilinear, but with the longer sides slightly arcuate. The dimension of the sheath along the minor axis of its cross-section is as small as possible to accommodate the systems, e.g., lens, irrigation, instrument channel, included in the instrument.
The radius of curvature of the arcuate sides is selected to approximately match the contours of the joint bones of interest, e.g., the femoral condyles and the tibial plateaus.

Description

~ackground of the Invention Field: This invention pertains to endoscopes in general and to arthroscopes in particular. Specifically, it provides such an instrument in a configuration ideal for use in arthroscopy.
State of the Art: Endoscopy is the art of examining the interior of a body cavity or hollow organ by the use of a slender tubular telescopic instrument called an "endoscope".
Endoscopes have been in common use since the early twentieth century. These instruments include a lens system, which may --1-- ~.
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be conventiollal glass lenses ~itllin a rigid tul)e, air sp lces bet~ een glass rods sllaped to configurate t]le entrapl)ed air .poekets as lenses, optieal glass fibers combined ~'ith COlI-ventional lenses, or other means; and a lighting system, which may be a direet ill.wnination system (e.gO, a tungsten light bulb) but is more often fiber light (light transferred from an external source t]lrough optical glass fil~ers)O Encloscopes also eommonly contain an irrigation system for introducing fluids, typieally normal saline solution, to the regioll being ~o examinedO These s~ stems are all eontained witllin a eylinclrieal tubular housing, usually called a "slleath", ~hich may be flexi-ble, but is more often ri~id. The cross-seetional eonfiguratio of the sheath normal~ its longitudinal axis (that is, as vie-~ed from the distal end of tlle endoscopc) is traditionally circularO
Examples of moderll en(loseopes are diselosed l~y U.SO
Patents Nos 3,525,332; 3,599,630; 3,608,547; 3,730,632;
3,744,906; 3,818,902; 3,819,267; and 3,889,662.
Endoseopes h~ve bcen used Eor artl~roscol)ic cxamina-tions for several decades Tllc clcvclopmcnt of artlll~oscor)y ao and instrumellts adopted Eor art:llroseopie e~camirlatiolls (artllro-seopes) is clescribe~l in tlle mono~-r;ll~ll "Artllroseol)y o:C tlle ~nee", Robert l\~o Jaekson alld I)avid JO l)a~l~ly, ~lo~lern Ortllopedie ~5OIlograp]ls ~ 1976 Grune ~, Str ltton, IneO, J~e~ YorkO l:rom the monograph, it is apparellt that tlle prillcip ll objeetive sought in developillg art]~roseopes has been to reduce their diameter eompared to earlier endoscopes. All of the compollellts eon-ventional to an endoseope, namely an optic~l system, a lighting system, an irrigation system, and often an~ strument ehannel, are eontained l~ithin a usual-ly rigid cylindrical sheatll of -~
3O approximately eireular cross-sectionO llle l~atallabe 22 shown in I~IGo 2-5 of t]le monograph utilizes a slleatll slig]ltly oval in cross-section to aecol;unodate t~o erescentic bundles of , , 1~30765 light fibers for illumination. The grouping of the light fibers in this fashion is to avoid the penumbra typically present in the center of the visual field.
Examination of the knee joint, or other joints, imposes certain restrictions on procedures not normally en-countered with other endoscopic examinations. For example, a persistent problem in arthroscopy has been maintaining ade-quate sterility. A circular cross-section is appropriate for introduction into the orifices of the genitourinary and gastro-intestinal tracts or for puncturing the abdominal wall, but the introduction of conventional round arthroscopes to the knee joint tends to be traumatic because of the limited spacing between bones. Conventional arthroscopes of small cross-section are susceptible of breakage if the knee is fle~ed or if too much force is applied in efforts to distract the joint using the arthroscope as a lever or fulcrum. In the past, less delicate arthroscopes have necessarily been constructed within sheaths of greater diameter.

Summary of the Invention The arthroscope of this invention departs substan-tially from the structural concepts traditional to endoscopes.
The instrument providcs the necessary components for examination (lens system, light system and usually an irrigation system) within a sheath housing having a cross-sectional configuration (taken normal the major axis of the arthroscope) which is neither circular nor oval, but is shaped as either a parallelogram or a modified parallelogram with a pair of approximately parallel longer sides and a pair of shorter sides which may also, but need not be parallel. The aforedescribed cross-sectional configuration is perceived by viewing the arthroscope from its distal end. Of substantial importance is that the spacing between the longer sides (referred to as the "thickness"

1~30765 of the instrumcnt) be as small as possible, haVi]lg d~lC rcgard to the space requirements of tllC components ~ hin tl~c sheatl10 In a dia~nostic arthroscope, the component of lar~cst diamcter is usually the lens systemO Tlle cross-sectional spacing bctl~een the longest sides of the sheath need tllen be just sufficient to accommodate tllis component~ Operating arthroscopes sometimes require larger sheat}ls to accommodate an instrument channel of greater diameter than t?le lens systemO
Tlle longer sides, l~hile ~enerally parallcl or approxi-mately parallel, are desirably arcuate ~ith a radius of curva-ture selected to appro~imately match the boncs of t]le jo;nt undergoing examinationO In most instances, wllen the longer sides are arcuate, one side l~all is concave and the other is convex, altllough it is possible for those side ~alls to be either mutually concave or convex~ The rac];us of cllrvature selected will necessarily vary accorcling to tlle corlstl-llction of the joint of interest~ size of the in-liviclual p~ticnt, and other f~ctors~ In pr~ctice, ho~ever~ a raclius of clllvature between about t~o and ~l~ollt tllrce ccntimeters is ~cllcrally ao appropriate Eor large jo:i.nts stlcl~ ~S tllc kllcec, hil- all(l slloulclcr joints O A raclials of .Ibollt 2~1/2 ccnt imcters is I;l cscllt:ly regarded as ideal Cor an instr~ cllt ill~ctlclc(l ~or ~cner~l purpose applicationsO
~ ltllougll the inst~ mcllts of tl~is invclltion a-re purposely constructed as tllin as possible, tlle spacing between tlle short sides of the cross section, (rcfcrrcd to as the "~idth" of the instrument) may ~e relatively largeO That is, consiclerable free~om of ~iiclth is perlnissible to accommodate a number of structllral featurcs not available ~ith conventional 3~ arthroscopes~ By ~ay of illustrationt the ~iclth of t]le instru ment may be enlarged to accommodate adclitional optic fibcrs, if gleater brilliallce at the opercltional site is clcsiredO

~lis feature has al~plicatio]l in instrulncnts a~apte(] for p]~oto-graplly or to incorporate tcac]~ing attacllmellts, for e~mple~
~or most applications, a~equate lighting is proviclc~ hcn the cross-sectional area of the optic fibers in the sheath approximately e~uals the cross-sectional area o~ tlle objective lens. Freedom of width also permits adaption of the distal end of the arthroscope as a retractor to move the synovium or the fat pad asideO ~loreover, tlle instrulnellt cl-anllel may be shaped to pass relatively ~ide instrull-ents, thercby o~vi-~o ating one of the limitations lleretorore imposcd on the clcsignof surgical instruments used ~it]l arthroscol~esO
One of the inllerent dif~iculties of mastering arthro-scopic techniques ll<as ~een the lac~ of ~Icytll plccel~tion provided by conventional arthroscopes. The incrcased ~idtll l-ermitted by the present invelltion o~fers t~o means for iml)ro~;nS on this situatiollO First, deptll percel~tion an~l persl-ective at the operative site is cnh~nccd by increasillg tl~c latcral spacillg of tlle o~jective lens from tlle (listill tCl`min.ltiOIl Or tl~e ;n-strument cllallnel. Tlle sur~eoll ~hus ol~crv~s tl-e ;nstrllmellt ao approaclling tlle operative site at ~ln Inl~le rllller tl~ln dilectly in his line o~ si~ht~ Secolld, it is ~ ill col~teml~latioll to mount a secolld lens sys~cll~ tlle sl~c;ltll, thel~c~y l)ro-viding true billocular ~isionO lit11er or ~o~ll of these e~pedi-Cllts l~i11 Cllall1e Illally lmOl`C S~ 'COI~S ~0 l~c(ollle s~il]Cul at arthroscopic sur~ery, and sl)ollld also perlnit tl~e ~e~e]opment of more intricate ~i~gnostic and sulgic~l proce(lures.
Of p~ramoullt importal~ce, the l'tllinlless" of the artl~roscopes of this invention permits more thorough e~amina-tion of joints tiith greater accur~cyO Tlle potential for false negati~e readi~?gs is greatly rcducedO (A "ncgati~e" rcading mea]ls that nothin~ l~rong is o~ser~ed,) l~hen the arcuate shape hcrci~lbefore dcscri~cd is incorl)or.lte(l, l~otll ~iagnostic and 1~30765 surgical procedures are further facilitated. The claimed arthroscopes often can probe to the interior of a joint without mechanically distracting the joint as in current practice.
The aforedescribed advantages are achieved with an attendant reduction of trauma to the patient. First, the soft tissues which must be penetrated to gain access to the joint space suffer markedly reduced trauma through use of this invention. Of even greater significance, from the standpoint of present expreience in the art, the present invention causes less trauma to the cartilage surface of the joint. In those instances when the tip of the arthroscope is used as a fulcrum, e.g., to pry open the back of a knee joint, the forces are spread over a larger surface area, thereby avoiding damage both to the cartilage and the instrument. The sheath of the claimed arthroscopes may be thicker than is now conventional.
Moreover, it is practical to contour and polish the sheath exterior to avoid laceration of the cartilage surfaces.
_ ief Descriptionof the Drawings In the drawings, which illustrate what is presently regarded as the best mode for carrying out the invention:
FIG. 1 is a typical operating arthroscope of this invention viewed from its distal end and showing the arrangement of its components;
FIG. 2 is a similar view of a typical diagnostic arthroscope of this invention;
FIG. 3 is a similar view of the arthroscope of FIG.
1 together with a series of prior art instruments drawn to the same scale;
FIGS. 4 through 6 illustrate various joints with an arthroscope of this invention in place; and FIG. 7 is a binocular version of an operating arthro-scope of this invention viewed from its distal end.
Description of the Illustrated Embodiments The operating arthroscope illustrated by FIG. 1 1~307~;5 compriscs a l~ns s~stcm, thc ob~cctivc lens 11 of ~hicll isvisible rrom the distal end of t]le instrumcnt; an irrigation system, inclucling the conduit 12; and an instrument channel 13; arrangcd ~ithin a rigid sheatll 14~ Thc intcrstitial sp~ces bet~een the components ll, 12 and 13 and ~it]lin the sheath 14 are packed with light-transmitting optic fibers lSo The artllroscope of FIGo 1 is constructed in generally conventional fashioll except for the cross-sectional shapc of the sheath 14 and the alrangcme]lt of tlle componcnts 11, 12, /o 13 and 15 houscd within the she~t}l 14. As viewed from its distal end, the cross-section of thc arthroscope may be con-sidered as llaving a minor axi.s, rcl~resented by line 20, which intersects i.t.s geomctric ccntcr 21; and a major axis, repre-sented by the line 22~ normal thc minor axis 21 at the center 21 The distal en(ls of instrumcllts ~itll regular cross-scctions will be ~i.sected into ~o congrucllt parts by tlle minor axis 20. as shownO
Thc slleatll 14 is o~ rig;(l, c.g., stainlcss stccl, constructlon, alld inclllclcs tl~o rc11t:ivcly l03lg s;~lc l~alls 31, ao 32 and two relativcly sl~ort sidc ~alls 33, 3~. 'I'hc sidc ~alls 31, 32 ~ ich intersect t.l-c m.inor a~is 20 arc ap~ ox;lllcltely ~ parallel Iclcal:Ly, tllcsc si.dc ~lls 31., 32 ;Irc ar~ tc~ .lS
S)IO~n, to apl)rox:illl;ltcly m.lt~.ll tl~c ~lrracc contours of tllc bones in a joi.ntO In the illllstl~ltc(l illSt.;lllCC, tllC raclills of cllrva-ture R is ~ppro~ ately 2.5 cclltilllctcrs, sidc ~all 31 is concave and side ~all 32 is convc~. T]lc short sidc ~.alls 33, 34 may also ~e apl~ro~imately parallel, as sho~ , and are ideally as short as possible; usually just long CnOU~ll to provide the minilllum spacing rc(luircd bet~een tlle side ~alls 31 and 32 to ~0 contain tl-c largest systcm housecl in the sheath 14 Ctlle instru-me3lt cllallllcl 13,~ FIGo 1; or tl~e lense systeln 41~ I IG~ 2~
The ~idtll (that is, thc spaci3lg of tllc si~c ~alls 33 and 34), of tlle instr~)c]lt is sc1ccted to ]~rovi(~e ade(luate cross-sectional area or the irrigation systcm C~ater channels 12, FIG~ 1 and 42~ ~IGo 2) dcsire~; the lig}~ting s~stcm ~optica1 fibers 15, FIG~ 1 and 45, ~IGo 2); and any otl-er systems w}lich may be inc1uded l~rithin the slleath~
` For applications requiring greater strength, the corners 50 connecting side ~alls, e~g~, 32 and 33, may be structurally reinforccd~ e~g., by thickening the sheath as sho~rn 51~ The lenses 11, 41 are shol~rn contained l~ithin rigid ~o tubes 50~ e~g " of structura1 ~lastic or meta10 The various chanJIels 12, 13, 42 are ty~ica11y defined ~y similar rigid tubes or conduit 51~
I,X~ll'LE I
The ol)erating artllroscope illllstrated by Fl~. 1 may be constructed ~itllin a s]leath 1~ mcasuri]lg ~l~out 3-1/2 by about 7 mi11imeters in cross section to hollse a lens s!~stem witll a 2,5 mm objective lense 11, a 3 m]n instrulnellt c1~al1ne1 13, a gellerous ~ater cha]lllel 12, all(l a]lll)le ol-tieal il-crs 15.
~X~II'J.l, II
ao The dia~]lostic instl~tlllent S]~O~ y ll~,. 2 lila)~ l)c constructed ~rithi]l a slleatl~ ~ me.lsllrinl~ .al)l)ro~ l.ltely 2-l/2 by about 4 millillletersO 'I'lle tcns s~";tCII) in SIICII a]l i])stlnllllCllt could have an objective ]ens ~ll as 1a~ C ;IS al-ollt 2.2 mm.
}'XA~ll'l,l I r I
,_ . _ , . . . _ I~IG. 3 com1~ares the rclative cross-scctiol1s of an instrument 60 constructcd as shol~rn in l~ . 1 an(l dcscribed in EX~lPLI, I ~itll a series 61, 62, 63 and 64 of conventiona1 instruments in cu`rrent use~ By l~ay of comparison, tlle cur-rently used instrlJmcnt 61 (a l~'o1 ol~crating arthroscope) contains ~0 a 2~5 mm o~jcctive lens 71~ a 3 mm instrumcnt channe1 72 and a l~air o~ irrigation crlannels 73 ~itllin a circular c~rlin~lrical sllcatll 7~ l)ac~ied ~ith sufficiellt optic i~er 75 to providc a(lc(lu;lte illumirlltionO Ihc shcath 74 is 6c5 mm in diameterQ Tl~e thickncss of thc instrumcnt of r;~A~II'LE I
is only slightly over half (about 54%) the diametcr of tllc comparable IYolf instrument, ancl provides for better irrigation at the operative site, ~he cross-scctional area of the in-strument of EXA~lP~E I is also significantly Cmore tllan ~0~
smaller, thereby requiring a smaller puncture wound for in-sertion Tlle other instruments 62, 63, 64 illustrated by /O FIG~ 3 have dlameters of 5, 2,5 and 2 2 mil]imeters, rcspec-tively, but include neither instrllment nor irrigation channels~
T]icse instrllrnents include only lenses alld o~tical fiber lightillg systems, and are useful for diagnostic ~plllications onlyO
~ IGSo 4~ 5 alld 6 illustrate tlle l~laccmellt of an art]~roscope 60, constructcd as taug}lt by ~ample I, ~rithin a ~lee jOillt, shoulder joint and hip joint, rcs~cctivclyO
The jOillts are shown in connection l~ith a rcfcrcnce circle 80~ Typical mature joints from tllc s~ e malc individual arc illustratcd compclred to a refcrcncc circlc \~i th a l`~ldiUs of aO approximately 2-1/2 CentilllCtCrSo 0f CoUrSC!, thc jOilltS o various indivi(lllals (lifcr sOIllC~i]);lt ;11 si~e al~l confi~ tion.
NeVertlleleSs, clS may l~e scen froln ~llc ,lr;~ s, a sillgle ;Irthro-scol~e oE stall(l<lrdi~cd dimens;oll Call lle used in all of thc major jOillts of khe majority of tl~c l~ulllall l~ol~ulatioll.
lYitllin tolerable limits, the sockcts defincd ~y the femur 81 and tibia 82 of tlle ~nee; thc scapull 83 and hu]nerus 84 of the slloulder; alld the femur 85, ilium 86 and pubis 87 of the hip are generally similar in configuration in a given individualO Accordingly, rclati~rely fe~ art]lroscopic instru 3~ ments constructed in accordaT-ce witl~ this in~tention are sufficicnt or a coml)lete diagrlostic antl treatmcnt service of tl~cse jointsO
~ ltllougll tllis disclosure has becll dircctcd slecifi-cally to arthroscol~cs an~ artlroscol~y, witll spcciic rcfercnce 1~30765 to certain illustrated embodiments, it is not intended to thereby limit the scope of the appended claims. It is within contemplation that the improvements disclosed and claimed herein may be adapted to endoscopes of various types. It is also contemplated that the teachings of this disclosure will lead directly to the development of practical instruments for the improved examination of smaller joints, such as those of the hands or feet. In such instruments, certain design changes, such as the desired radii of curvature for the arcuate side walls of the sheath, are expected. It is also within contemplation that the lens system be adapted to provide a line of sight divergent from the central longitudinal axis of the sheath. An arthroscope in a sheath shaped as in FIGS.
1 and 2, for example, may be provided with a lens system presenting a line of sight canted about 20 toward the concave surface.
The binocular version illustrated by FIG. 7 includes a pair 91, 92 of lens systems.

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An arthroscope with structural elements including a lens system and a fiber optic lighting system fixed within an elongated rigid sheath, said sheath having a cross-sectional configuration, as viewed from its distal end, defined by a pair of approximately parallel longer sides and a pair of shorter sides, said sheath having major and minor axes intersecting at the geometric center of said cross-section, and the dimension of the cross-section of the interior of the sheath along the said minor axis being just sufficient to accommodate the largest of said elements.

2. The arthroscope according to Claim 1, wherein an instrument channel extends longitudinally of the sheath in approximately parallel relationship with the lens system, the lens system and instrument channel being in side-by-side relationship along approximately the said major axis.

3. The arthroscope according to Claim 1, including an irrigation system element extending longitudinally of the sheath in approximately parallel relationship with the lens systems, the lens system and the irrigation system element being in side-by-side relationship along approximately the said major axis.

4. The arthroscope according to Claim 3, wherein an instrument channel extends longitudinally of the sheath in approximately parallel relationship with the lens system, the lens system and instrument channel being in side-by-side relationship along approximately the said major axis.

5. The arthroscope according to any one of Claims 1-3, wherein said lighting system includes optic fibers arranged within the interstitial spaces between the elements contained within the sheath and the side walls of the sheath.

6. The arthroscope according to any one of Claims 1-3, wherein the opposing shorter sides of the cross-section are approximately parallel each other.

7. The arthroscope according to any one of Claims 1-3, including a pair of said lens systems spaced along said major axis and approximately parallel the longitudinal axis of said sheath, and optic fibers packed in the interstices between the said elements and the interior surface of said sheath.

8. The arthroscope according to any one of Claims 1-3, wherein the opposing sides of said cross-section which intersect said minor axis are each arcuate on a radius select-ed to approximately match the contours of adjacent bone surfaces comprising a joint.

9. The arthroscope according to any one of Claims 1-3, wherein one of the longer sides of the cross-section is concave and the other longer side is convex.

10. An arthroscope according to any one of Claims 1 3, wherein the cross-section of said sheath as defined by said longer and shorter sides projects to the free distal end of the sheath so that the arthroscope at the distal end of the sheath is free of sideward projections or enlargements.