US3640280A - Power-driven reciprocating bone surgery instrument - Google Patents

Abstract

A bone surgery tool is provided with a reciprocating drive means. The tool and a flexible drive band can be enclosed in a shroud to protect tissue against contact with the tool or the driving means. The shroud can also contain a channel for a flushing fluid. The power unit can utilize a double-acting fluid piston, with the reversal in the direction of movement of the piston being effected by a fluidic control device.

Description

Slanker et a1.

Feb. 8, 1972 POWER-DRIVEN RECIPROCA'IING 1 3,155,011 11/1964 Hyskell ..30/l66 x BONE SURGERY INSTRUMENT 3,427,480 2/1969 Robinson ..32/46 X [72] Inventors: Daniel R. Slanker, 2639 S. 90th East, Tul- FOREIGN PATENTS OR APPLICATIONS gi gfli gifiglfi fififl' g 483,135 5/1952 Canada ..30/166 352,673 5/1922 Germany ..32/46 [22] Filed: Nov. 26,1969

1 Primary ExaminerAndrew R. Juhasz [2]] App! 880,094 Assistant Examiner-Michael Koczo, Jr.

AttomeyJarnes W. Williams [52] US. (.l 128/317, 3O/16?5?I/28/l1t35, ABS CT [51] Int.Cl. ..A61b 17/14,B23d 49/16 A bone surgery tool is provided with a reciprocating drive [58] Field of Search ...30/l66; 128/317; 145/31 R, eans- T e tool and a flexible drive band can be enclosed in a 145/31 13 31C 31 1); 32/4 47 shroud to protect tissue against contact with the tool or the driving means. The shroud can also contain a channel for a l 56] References Cited flushing fluid. The power unit can utilize a double-acting fluid piston, with the reversal in the direction of movement of the UNITED STATES PATENTS piston being effected by a fluidic control device.

1,326,166 12/1919 Backus ..128/3 17 UX 9 Claims, 18 Drawing Figures 5 670I 14 1112 N3 I; 7) as a; 67 L 1 1H m 1 1 1 1 2| 72 5a, 74' (75L 76 8 6 0 F 32l 4 421 -1 a 49' 4 n :3 6 1 g -95 61 5$ 42 7/ L n I J 40 104 I07 41 5 23t 4 2- 40 1 64;; 99 L 1 22 1 12 9 l l l A v L 1 1 1 fiX/M PATENIEU FEB 8 .2

SHEET 3. [1F 3 mm m mO bl mi m. 5 F029 INVENTORS D R. SLANKER E. E SLANKER JnEDW 12 WWI] FEB 8 I972 SHEEY 3BF 3 VE SSSSS ER SSSSS ER POWER-DRIVEN RECIPROCATING BONE SURGERY WSTRUIVENT The invention relates to a power-driven reciprocating bone surgery instrument. In one aspect the invention relates to a reciprocally driven bone-abrading tool. In another aspect the invention relates to a reciprocating bone surgery tool enclosed in a shroud. In yet another aspect the invention relates to a pneumatic-powered reciprocating drive for a surgical instrument.

Several types of powered bone-abrading instruments are commercially available. However, to our'knowledge, each of these instruments utilizes either a rotating abrading tool surface or an arcuate abrading surface which is oscillated about the axis of the arc of the abrading surface. Both types present significant problems in the utilization thereof in various circumstances. With both types it is necessary that'the soft tissue be well retracted from the area of the bone to be abraded to prevent contact of the abrading surface with the tissue and to permit visual observation of the abrading action. Thus, a large incision is required. The rotary-driven tool presents a problem with changes in speed. If the speed of the tool is decreased or increased, the tool tends to move laterally in an arc, the direction of lateral motion depending upon whetherthe speed is increased or decreased. Thus, considerable skill is required in maintaining the desired position of the abrading tool when a variation in speed is being made. Furthermore, if the rotating abrading tool is not maintained parallel to the surface being abraded or if areas of different hardness are encountered by opposite sides of the tool, the resulting unbalanced forces will result in undesirable lateral movement of the tool. The oscillating arcuate abrading tool generally cuts in both directions of movement, so that the surgeon must try to maintain the position of the instrument despite any unexpected variations in resistance encountered in either direction. This is not only a physical strain on the surgeon, but any unexpected slip in the positioning of the instrument can result in damage to the adjacent tissue.

Due to the danger to the patient and the surgeon of electrical shock, as well as the possibility of explosion if oxygen is being administered to the patient, it is highly desirable that the driving means for the bone surgery instrument be fluid actuated.

In accordance with the present invention, the disadvantages of the prior art instruments are avoided by the utilization of a reciprocally power-driven bone-abrading tool, which can be enclosed within a shroud. The utilization of a flexible driving band within the shroud permits the shroud to be either curved or straight. The shroud can also provide a means for directing a flushing fluid onto the bone area being abraded from the remote end of the work area, to thereby flush bone fragments from the work area. With the protective-shroud, the abrading instrument can be inserted under the flesh, thus permitting a remote incision.

Accordingly, it is an object of the invention to provide a new and improved powered surgical instrument. It is an object of the invention to provide a powered bone-abrading instrument which minimizes the strain on the surgeon and which provides greater protection for the patient. Another object of the invention is to minimize, if not eliminate, the possibility of damage to surrounding tissue in a bone-abrading operation. A further object of the invention is to provide a bone-abrading tool having a flexible, reciprocating drive means. Yet another object of the invention is to provide means for directing a flushing fluid onto the area of the bone being subjected to abrasion. It is an object of the invention to permit a bone abrasion operation with a smaller incision or even with a remotely located incision.

Other objects, aspects and advantages of the invention will be apparent from a study of the specification, the drawings and the appended claims to the invention.

In the drawings:

FIG. I is an illustration, partly in elevation and partly in diagrammatic form, of a reciprocating bone surgery'instrument in accordance with one embodiment of the invention;

FIG. 2 is an elevational view in cross section along the length of the instrument of FIG. 1;

FIG. 3 is an elevational view in cross section, taken along the line 33in FIG. 2;

FIG. 4 is an elevational view in cross section, taken along the line 4-4 in FIG. 2;

FIG. 5 is an elevational view in cross section, taken along the line 5-5 in FIG. 2;

FIG. 6 is an elevational view in cross section, taken along the line 6-6 in FIG. 2;

FIG. 7 is an elevational view in cross section, taken along the line 77 in FIG. 2;

FIG. 8 is an elevational view in cross section, taken along the line 8-8 in FIG. 2;

FIG. 9 is an elevational view in cross section, taken along the line 9-9 in FIG. 2;

FIG. 10 is an elevational view. in cross section, taken along the line 10-10 in FIG. 2;

FIG. 11 is a top view of the flexible driving band of FIG. 2; FIG. 12 is a bottom view of the bone-abrading tool of FIG.

FIG. 13 is a top view of the bone-abrading tool of FIG. 12;

FIG. 14 is a bottom view of a bone-abrading tool having the teeth thereof curved in a convex manner, which can be employed in the instrument of FIG. 2;

FIG. 15 is a bottom view of a bone-abrading tool having the teeth thereof curved in a concave manner, which can be utilized in the instrument of FIG. 2;

FIG. 16 is an elevational view of an inwardly curved tool shroud which can be utilized instead of the straight tool shroud of FIG. 1;

FIG. 17 is an elevational view of an outwardly curved tool shroud which can be utilized instead of the straight tool shroud ofFIG. 1; and

FIG. 18 is a partial cross-sectional view of the front end of a tool shroud equipment with ball bearings.

Referring now to the drawings in detail, and to FIGS. I and 2 in particular, the bone surgery instrument comprises an elongated housing 1, which serves as a handle and which'contains the reciprocating drive mechanism, atool shroud 2, a bone-abrading tool3, and aflexible hose 4 having at least twofluid conduits 5 and 6 therein. Conduit S is connected through valve 7, whichmay bemanually actuated by a foot pedal or other suitable means to vary the reciprocating speed, to a pressurizedair supply 8.Conduit 6 is connected through manually actuatable valve 9 tosupply ll of a flushing liquid under pressure. Housing 1 comprises a cylindricallyshaped body member 12,,the exterior surface of which can be knurled or shaped to provide a gripping surface for the tool.Body member 12 is provided with externally threaded, recessedportions 13 and 14 at the front and rear ends thereof, respectively. Thetool shroud 3 is secured to the front end ofbody member 12 by means of internally threadedclamp ring 15. Similarly, thefluid inlet connector 16 is secured to the rear end ofbody member 12 by internally threadedclamp ring 17. The outlet end ofhose 4 has an outwardly extendingflange 18, which abuts against a similarly outwardly extendingflange 19 on the inlet end ofconnector 16. Ring clamp 21 is internally threaded to engage external threads on flange I9, and has an inwardly directedflange 22 to holdflange 18 in fluidtight contact with flange w.Flanges 18 and 19 can be suitably shaped to permit contact thereof only withfluid conduits 5 and 6 ofhose 4 in alignment withfluid passageways 23 and 24, respectively, inconnector 16, or one of the flanges I8 and 19 can be provided with positioning pins to engage openings in the other flange to accomplish the correct positioning.

Referring now to FIGS. 1, 2, 3 and 4,shroud 2 comprises ashank section 25 of circular cross section and atool section 26.Shroud 2 is provided with aguideway 27 of substantially rectangular cross section in substantial conformity to and slightly larger than the cross section of theflexible driving band 28. The upper portion of abradingtool 3 has laterally extendingflanges 29 on the front and on each side thereof substantially confonning to the rectangular cross section ofpassageway 27. The height of therear portion 31 oftool 3 is reduced by at least the thickness of drivingband 28. Therear portion 31 is provided with an upstanding pin 32 (FIG. 13) which fits within and closely conforms to anopening 33 in the front end of driving band 28 (FIG. 11).Shank portion 25 is provided with anopening 34 to permit the insertion of thetool 3 therethrough in the assembling of the instrument. Similarly,tool section 26 is provided with anelongated slot 35 in communication withguideway 27 to permit the insertion and subsequent reciprocation of thetool 3.Slot 35 is wider than thetoothed portion 36 oftool 3, but narrower thanband 28 andflanges 29. Thus the path of movement of drivingband 28 andtool 3 is determined byguideway 27.Shroud 2 is provided with afluid passageway 37 extending from theshank portion 25 along the upper portion oftool section 26 to a point in front of the front end ofslot 35 and then downwardly to the lower surface of the tip of theshroud 2 to direct a steam of flushing front at the far end of the work area.Body member 12 has afluid passageway 38 to provide communication betweenpassageways 24 and 37.

Referring now to FIGS, 2 and through 10, the inner orrear end 41 ofband 28 is secured by suitable means, for example by threaded engagement, to the forward end of reciprocatingshaft 42.Shaft 42 extends through sealing rings 40 positioned in aligned openings indisc 43, 44, 45, 46 and 47. Each adjacent pair of disc 43-47 is separated by a respective one ofcylindrical sleeves 48, 49, 50 and 51. Asleeve 52 separates disc 43 and asolid closure disc 53, which is positioned in arecess 69 inconnector 16.Discs 43, 44, 45, 46 and 47 and sleeves 48-52 are positioned within acylindrical opening 54 extending axially throughbody member 12, and are rigidly held in place bysplit ring 55 engaging an annular slot 56 in the inner wall ofbody sleeve 12.Discs 43 and 44 andsleeve 48 form achamber 57.Discs 44 and 45 andsleeve 49 form achamber 58. Similarlydiscs 45 and 46 andsleeve 50form chamber 59, whilediscs 46 and 47 andsleeve 51 form chamber 60.Shaft 42 has secured thereto radially extendingpiston diaphragm flanges 61, 62, 63, 64 and 65.Flange 61 is located inchamber 57 and sealably engages the inner wall ofsleeve 48 to divide thechamber 57 into front and rear sections.Flanges 62 and 63 are located spaced-apart relationship inchamber 58 and sealably engage the inner wall ofsleeve 49 to dividechamber 58 into front, middle and rear sections.Flange 64 is positioned inchamber 59 and sealably engages the inner surface ofsleeve 50 to dividechamber 59 into front and rear sections. Similarly, flange 65 divides chamber 60 into a front section and a rear section. The sealing engagement of each of thepiston flanges 61, 62, 63, 64 and 65 to the corresponding sleeve can be effected by any suitable means, for example O-rings 66.

Akeyway 67 is cut inbody 12 along the surface ofcylindrical opening 54 parallel to the axis ofopening 54. A matchingkeyway 67a is cut in the cylindrical wall ofrecess 69 ininlet connector 16. Key 71 is positioned inkeyways 67 and 67a. Corresponding keyways 72-82 are cut indisc 53,sleeve 52, disc 43,sleeve 48,disc 44,sleeve 49,disc 45,sleeve 50,disc 46,sleeve 51 anddisc 47, respectively, to receive and engage key 71 to maintain an accurate alignment of the discs and sleeves withinconnector 16 andbody 12. The internal surface ofbody 12 is also cut to providegrooves 83, 84, 85, 86 and 87 which extend parallel to the axis ofcylindrical opening 54. The cylindrical wall ofrecess 69 inconnector 16 is similarly cut to provide correspondingly locatedgrooves 83a, 84a, 85a,86a and 87a. v

Afluid control disc 91 is positioned withinrecess 69 ofinlet connector 16. The end ofdisc 91 in contact withdisc 53 is grooved to form a fluidic amplifier which serves as a control switch. The power inlet passageway 92 extends throughdisc 91 into communication withfluid passageway 23 ininlet connector 16. The control or biasingfluid passageways 93 and 94 communicate withgrooves 83a and 84a, respectively. The firstpower output passageway 95 communicates with groove a, while the secondpower output passageway 96 is connected to groove 86a.

Passageway 97 insleeve 49 provides fluid communication for the second power output fluid stream fromgrooves 860 and 86 into the front section ofchamber 58. Similarly passageways 98 and 99 connectgroove 86 to the front section ofchamber 59 and 60, respectively.Passageways 101, 102 and 103, insleeves 49, 50 and 51, respectively, provide for the passage of the first poweroutput fluid grooves 85a and 85 into the rear sections ofchamber 58, 59 and 60, respectively.Shaft 42 is provided with an axiallyelongated passageway 104 havinginlets 105, 106 and 107 andoutlets 108. In the final portion of the rearward stroke ofshaft 42, as illustrated in FIG. 2, and in he initial portion of the forward stroke ofshaft 42, theinlets 105, 106 and 107 are in the front sections ofchambers 58, 59 and 60, respectively. In the final portion of the forward stroke ofshaft 42, theinlets 105 and 106 pass throughdiscs 45 and 46 into the rear section ofchambers 59 and 60, respectively, whileinlet 107 becomes closed off by the greater thickness ofdisc 47.Outlets 108 permit continuous fluid flow frompassageway 104 through the middle section ofchamber 58, outlet opening 109,groove 87,groove 87a, and exhaust port 111 to the atmosphere,Passageway 112 andgrooves 83 and 83a provide communication between the rear section ofchamber 57 andcontrol inlet passageway 93, whilepassageway 113 andgrooves 84 and 84a connect the front section ofchamber 57 to controlinlet passageway 94.

At approximately the position shown in FIG. 2, the pressure feedback from the rear section ofchamber 57 to controlinlet 93 becomes sufficiently greater than the pressure feedback from the front section ofchamber 57 to controlinlet 94 to divert the flow of the fluid from inlet 92 to power output passageway andgrooves 85a and 85. This causes a buildup of pressure in the rear sections ofchambers 58, 59 and 60 againstpistons 62, 64 and 65, resulting in the forward movement ofshaft 42. At the end of the forward movement ofshaft 42, the pressure feedback from the front section ofchamber 57 to controlinlet 94 has become sufficiently greater than the pressure feedback from the rear section ofchamber 57 to controlinlet 93 to divert the flow of fluid from inlet 92 topower output passageway 96 andgrooves 86a and 86. This causes a pressure buildup against the front surfaces ofpistons 63, 64 and 65, resulting in the rearward movement ofshaft 42. The frequency of the reciprocating motion ofshaft 42 is determined by the pressure of the fluid inconduit 23, which is controlled by manual manipulation of valve 7. Due to the confinement of theflexible driving band 28 inguideway 27, the reciprocation ofshaft 42 effects a corresponding reciprocating motion of abradingtool 3.

Reasonable variations and modifications of the bone surgery instrument are possible within the scope of the invention. As shown in FIGS. 14 and 15, the abrading tool can have convexly shaped teeth 36a or concavely shaped teeth 36b instead of thestraight teeth 36 of FIG. 12. Other teeth configurations and combinations thereof can also be employed. Furthermore, as illustrated in FIGS. 16 and 17, the versatility of theflexible driving band 28 pennits the utilization of an inwardly curved shroud tool section 26a or an outwardly curved shroud tool section 26b, the curvature ofguideway 27 being in a plane perpendicular to the width offlexible band 28. Theshroud 2 can be made of rigid material, such as stainless steel, or of material of sufficient flexibility to permit adjustment of the longitudinal curvature of the shroud during operation of the instrument. For example, a disposable, flexible shroud of hard rubber can be employed. In the larger sizes of the bone surgery instruments, it may be desirable to provide friction reducing means. One example of such means is theball bearing plate 121 illustrated in FIG. 18.Plate 121 is positioned in tool section 260 immediately above the upper surface oftool 3. While the presently preferred embodiment of the invention has been illustrated in the drawings as having thetool 3 inserted into thetool section 26 of theshroud 2 through anopening 34 in theshank portion 25 ofshroud 2, it is within the contemplation of the invention to utilize other shroud configurations which permit the insertion of the tool from the front end of the shroud, for example by the utilization of a detachable tip. Similarly, while it is preferable that a pneumatic driving means be employed to power the reciprocating tool, other means can be utilized. Thus, in the field of veterinary surgery, it would be permissible to employ electrically actuated reciprocating drive means to power the instrument. While air is the preferred power fluid from the standpoint of safety and economy, other fluids can be utilized when desired, for example, nitrogen or carbon dioxide.

The enclosure of theabrading tool 3 and the drivingband 28 within theshroud 2 permits the tool to be inserted under soft tissue without damage to the tissue. This permits a technique wherein the incision is made at a point remote from the bone area to be abraded. The soft tissue can be separated from the bone from the point of incision to the area to be abraded, and the instrument can be inserted. The presence of the shroud also permits the utilization of a smaller incision as the gingival and soft tissue retraction would not be necessary to the extent required for a rotary or oscillating instrument. The occurrence of the abrading action only on the backstroke minimizes the occurrence of unbalanced forces in positioning the instrument, thereby reducing the strain on the surgeon. Thus, no forward pressure by the surgeon is required, eliminating the possibility of slipping and penetration of tissue or even vital structures. This gives the surgeon a greater tactile sense of control than is present with a rotary or oscillating instrument. The location of the flushing fluid outlet at the tip of the shroud permits the flow of the flushing fluid back along the path of insertion of the instrument, thereby facilitating the removal of the bone particles from the incision, as well as providing a cooling action for the work area, if desired. The remote location of the incision is particularly advantageous in facial surgery, such as operations on the nose. The invention is particularly useful with dental equipment, as the instrument can be attached directly to the conventional pneumatical power supply and controls. The invention is also useful for reducing bony tori, both maxillary and mandibular; reducing lingual bony shelf; for maxillary tuberosities, alveolectornies, alveolar osteoplasty, foot surgery, rhinoplasty, bone sculpting in plastic surgery, bone sawing, orthopedic surgery, autopsy surgery, skull surgery, veterinary surgery, and vein surgery.

We claim:

l. A reciprocally power-driven cutting instrument comprising a handle, an elongated shroud attached to the forward end of said handle, said shroud having an internal guideway extending along at least a portion of the length of said shroud and having a tool opening extending from at least a portion of said guideway to the exterior of said shroud, a cutting tool positioned in said tool opening, said cutting tool having retention means extending into said guideway to couple said tool to said shroud while permitting said tool to freely move along said guideway, and power means connected to said tool to effect reciprocation of said tool within said tool opening along the path of at least a portion of said guideway; said power means comprising a shaft mounted in said handle in alignment with the rear end of said shroud, means for reciprocally driving said shaft, and a flexible band positioned in said guideway, the rear end of said flexible band being connected to the front end of said shaft, the front end of said flexible band being connected to said cutting tool.

2. An instrument in accordance with claim 1 further comprising friction reducing means mounted in said shroud in contact with the inner surface of said tool.

3. An instrument in accordance with claim 1 wherein said guideway is curved in a plane perpendicular to the width of said flexible band.

d. An instrument in accordance with claim 1 wherein said shroud comprises a shank section and an elongated tool section, said guideway and said tool opening extending rearwardly through said shank section to permit the insertion of said tool and said flexible band into said shroud from the rear end of said shank section, and further comprising means for securing said shank section to said handle.

5. An instrument in accordance with claim 1 wherein said means for reciprocally driving said shaft comprises at least one power chamber and at least one control chamber formed in said handle; said shaft extending through said at least one power chamber and at least one control chamber; at least one piston flange mounted on said shaft in each said at least one power chamber and dividing each said at least one power chamber into a front section and a rear section; at least one piston flange mounted on said shaft in each said at least one control chamber and dividing each said at least one central chamber into a front section and a rear section; a fluidic amplifler having a power input, first and second control inputs and first and second power outputs; means for supplying a fluid under pressure to said power input; means providing fluid communication between the rear section of each said at least one control chamber and said first control input; means providing fluid communication between the front section of each said at least one control chamber and said second control input; means providing fluid communication between said first power output and the rear section of each said at least one power chamber; and means providing fluid communication between said second power output and the front section of each said at least one power chamber, so that the movement of the piston in each said at least one control chamber varies the relative magnitude of the pressure signals applied to said first and second control inputs to effect a switching of the flow of fluid entering said power input to said first power output at the end of the rearward motion of said shaft and to said second power output at the end of the forward motion of said shaft.

6. An instrument in accordance with claim ll wherein said shroud is provided with a fluid passageway extending to a point in the forward tip of said shroud, and further comprising means for supplying a flushing fluid to said fluid passageway, and wherein said cutting tool is a bone surgery abrading tool.

7. An .instrument in accordance withclaim 6 wherein said guideway is curved in a plane perpendicular to the width of said flexible band.

8. An instrument in accordance with claim 1 wherein said shroud is formed of material of sufficient flexibility to permit adjustment of the longitudinal curvature of said shroud.

9. An instrument in accordance with claim 1 wherein said means for reciprocally driving said shaft comprises a double acting fluid piston and a fluidic control device connected to effect periodic reversals in the direction of movement of said piston.

Claims (9)

1. A reciprocally power-driven cutting instrument comprising a handle, an elongated shroud attached to the forward end of said handle, said shroud having an internal guideway extending along at least a portion of the length of said shroud and having a tool opening extending from at least a portion of said guideway to the exterior of said shroud, a cutting tool positioned in said tool opening, said cutting tool having retention means extending into said guideway to couple said tool to said shroud while permitting said tool to freely move along said guideway, and power means connected to said tool to effect reciprocation of said tool within said tool opening along the path of at least a portion of said guideway; said power means comprising a shaft mounted in said handle in alignment with the rear end of said shroud, means for reciprocally driving said shaft, and a flexible band positioned in said guideway, the rear end of said flexible band being connected to the front end of said shaft, the front end of said flexible band being connected to said cutting tool.

2. An instrument in accordance with claim 1 further comprising friction reducing means mounted in said shroud in contact with the inner surface of said tool.

3. An instrument in accordance with claim 1 wherein said guideway is curved in a plane perpendicular to the width of said flexible band.

4. An instrument in accordance with claim 1 wherein said shroud comprises a shank section and an elongated tool section, said guideway and said tool opening extending rearwardly through said shank section to permit the insertion of said tool and said flexible band into said shroud from the rear end of said shank section, and further comprising means for securing said shank section to said handle.

5. An instrument in accordance with claim 1 wherein said means for reciprocally driving said shaft comprises at least one power chamber and at least one control chamber formed in said handle; said shaft extending through said at least one power chamber and at least one control chamber; at least one piston flange mounted on said shaft in each said at least one power chamber and dividing each said at least one power chamber into a front section and a rear section; at least one piston flange mounted on said shaft in each said at least one control chamber and dividing each said at least one central chamber into a front section and a rear section; a fluidic amplifier having a power input, first and second control inputs and first and second power outputs; means for supplying a fluid under pressure to said power input; means providing fluid communication between the rear section of each said at least one control chamber and said first control input; means providing fluid communication between the front section of each said at least one control chamber and said second control input; means providing fluid communication between said first power output and the rear section of each said at least one power chamber; and means providing fluid communication between said second power output and the front section of each said at least one power chamber, so that the movement of the piston in each said at least one control chamber varies the relative magnitude of the pressure signals applied to said first and second control inputs to effect a swiTching of the flow of fluid entering said power input to said first power output at the end of the rearward motion of said shaft and to said second power output at the end of the forward motion of said shaft.

6. An instrument in accordance with claim 1 wherein said shroud is provided with a fluid passageway extending to a point in the forward tip of said shroud, and further comprising means for supplying a flushing fluid to said fluid passageway, and wherein said cutting tool is a bone surgery abrading tool.

7. An instrument in accordance with claim 6 wherein said guideway is curved in a plane perpendicular to the width of said flexible band.

8. An instrument in accordance with claim 1 wherein said shroud is formed of material of sufficient flexibility to permit adjustment of the longitudinal curvature of said shroud.

9. An instrument in accordance with claim 1 wherein said means for reciprocally driving said shaft comprises a double acting fluid piston and a fluidic control device connected to effect periodic reversals in the direction of movement of said piston.

Images