CA2405193C

CA2405193C - Device for working on human and/or animal tissue

Info

Publication number: CA2405193C
Application number: CA2405193A
Authority: CA
Inventors: Alexander Joist
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-04-05
Filing date: 2001-03-20
Publication date: 2010-05-25
Anticipated expiration: 2021-03-20
Also published as: JP4346274B2; JP2003529437A; ES2288930T3; DE20006247U1; US7344513B2; CN1262246C; US20030163136A1; CN1422138A; EP1267731B1; ATE365504T1; WO2001076491A1; CA2405193A1; DE50112663D1; AU4249001A; AU2001242490B2; EP1267731A1

Abstract

The invention relates to a device for treating the human and/or animal body, for example a core drill, especially an intramedullary reamer for tubular bones, which has a drill head (12). Said drill head (12) is connected to a flexible shaft (14) which is in turn connected by a shank (16) to a drilling machine. The core drill also has a rinsing unit (18) by which means drilled material is removed in the area of the drill head (12). The rinsing unit (18) is connected to a rinsing channel (30) for this purpose, said rinsing channel being configured between the bore and the outside diameter of the flexible shaft (14). The drill head (12) has slits (34) which are connected to an inner cavity (36) of the drill head (12). Said cavity (36) is in turn connected to an inner channel (40) provided in the flexible shaft (14). The rinsing medium is guided into a rinsing head (42) through said inner channel. In the rinsing head (42), the rinsing medium enters a ring-shaped channel (58) through slits (60) provided in the flexible shaft (14). Said ring-shaped channel (58) is connected to a channel (54) to a which a suction device is connected by flexible tubing (56).

Description

Device for working on human and/or animal tissue I
I
The present invention refers to a device for working on human nd/or ani mal tissue, in particular an arthroscope, an endoscope or a co a rill, in par titular a intramedullary reamer for tong bones such as femu s.
Arthroscopy is used to enter cavities in human or animal jaint~ s as to wor on the surface of a bone, for example. This work may be the s nothing a the surface. Further, arthroscopy is also useful in removing toss e, such a l in the removal of bone parts from joints by milling, scraping ~nd the like. Ii endoscopy, human tissue is treated in similar fashion; howe ~ r, endoscop~
is not employed in joint cavities but in any other part of the a an or ani mal body.
With fractures of Ivng tubular bones such as femurs, both ~on parts are first aligned and then bored in the longitudinal direction. S~jbs quently, ~
nail is inserted into the bore to fix both bone parts. l The bore is provided by first inserting a guide pin into the b~n marrow both bone parts. The guide pin is a wire with a diameter of zlto 3 mm. T
guide pin serves to guide a drill head. The drill head is connect to a flexi ble shaft driven by a drill drive, such as a pneumatic drill.
When forming the bore, high pressure is generated head.
at the dril Th pressure pushes bone and fat tissue into venae. , there In this cont~x is chance of those particles being transported ~elood into the lung via ti vess~

and causing pulmonary embolism. In particular, b ne if besides th~ fractur also the lungs are injured, the two bone parts b the cannot be fixe nailin describe above since the risk of pulmonary embolism a wool too higl Thus, the bone can only be fixed from outside. ene, As a cansequ the fret tore often heals poorly, an proper anatomic ~uis setting of the frac dlfficui~

infections of the soft-tissue environment occurb,ossibly, frequently, an th definite treatment of the fracture has to be c nd performed in a s surgica operation.

z CH 687 228 A5 discloses a special drill head yaming for intermedullarj de~

signed to reduce the pressure at the drill head.hs opening:
The drill head through which the drilled material, primarily cn be trans.
the bone marrow ported rearward. However, since a flexible shaft~ta drill is located in hole there is only little space for' accommodating ria. Thus, the drilled matel the amount of drilled material is larger than the erill so space behind th thaw the drilled material is further compressed. s up in Thus, pressure b~.ril the area of the drill head. This may result in drilled ached material being ou~

into the lung via blood vessels and causing ~is pulmonary embo The problems of increased pressure buildup are also disadvarSta eous whet endoscopes and arthroscopes are used and I ay cause the bove men tinned problem, respectively.
It is the object of the invention to provide a device for wor n on humai and/or animal tissue, in particular a core drill, especially usef~rl r inlarme dullary reaming in tubular bones, which avoids pressure bull -up at the working head.
The object is solved with the features of claim l.
When the device of the present invention is ries a a core drill, it comp wash ing unit by which the drilled material is transportedm a area away frd o the working head. In a cor drill, the working . y continu head is a drill head ously washing, the material removed, i.e., the isashed drilled material ou from the medullary space of the bone, for example,p assure so that n~ car be generated within the bone and especially d.Due to at the drill hea thi pressure-less core drill according to the presentrik of invention, th f~ drilled material being washed into the lung and, thus,~theo ary embo risk of pulr~

lism is avoided.
l CA 02405193 2002-10-0T.
According to the invention, the core drill comprises a flexible Ish~ft with an inner channel. Further, the drill head connected to the flexibl shaft has openings in communication with the inner channel. Accordingito the inven-tion, a washing unit is provided, having a contact surface that allows the washing unit to be applied to an object in a substantially sealed anner. If the core drill is used for intermedullary reaming, the object i a tubular bone. Further, according to the invention, the diameter of the ~Nv king head, as well as that of the drill head, is larger than the outer dim ter of the flexible shaft so that a washing channel is formed between the~o er surface of the flexible shaft and the drill hole produced in an object, s~ch~ as a tubu-lar bone.
i I
When drilling tubular bones, a washing mediu ~ is introduced iht the wash-ing channel from the washing unit. Thus, the rivashing mediu ' ows along the outer surface of the flexible shaft towards tie drill head. Si~nc the wash-ing unit has a contact surface that o a substantially seals off the p surface, the washing medium can be introduced eln a simple into the washing chanc i manner. At the drill head, the washing ntrior medium flows into the f of the drill through the openings in the w shing drill head. In the process, th me-~

dium takes up the drilled material ~ d through and transports the same in a the openings in the drill head. gs communicaa ith Since the openi the in-ner channel of the flexible shaft, edium is o ed the washing trans. into tfie interior of the flexible shaft. l shaft, In the inner channel of the flexi~ the washing medium and the drilled material t a are carried out frani bone to-wards the washing unit.
The washing medium may also be transported In tins, reversed dire~c so tt the washing medium flows through the inner cannelxi1e of the flg shaft the drill head, leaves from the openings thereofg d from and Is discha~- t bone through the washing channel. However, bischargingw shing th~ m dium through the Inner channel of the flexible g ous shaft is advant~ fn th the drilled material is not guided along the This inner wall of the bare cot cause the drill hole to become clogged and might thus lead t~ l juries at t inner wall of the bare.
Providing a washing unit is further advantageous in that nol h at is genE
ated at the drill head that could cause tiSSUe~Changes.
I
l Preferably, the washing unit comprises a suction device to gen rate a v~
uum at the drill head. Generating the vacuumiguarantees thalt a ( drilled m terial is discharged immediately. Thereby, the accurrencel o pressure avoided at the drill head, which could cause drilled materi I o enter t blood vessels of a atient. Preferabl the suction device is ~o netted w l' Y
the inner channel of the flexible shaft so that dhe washing midi m is suck out through the inner channel together with the drilled mate) is . This is a vantageous in that the sealing between the ciontact surface f he washi unit and the object need not be of a particularly wel9 sealing es gn, since high pressures occur at the contact surface (n this directivn,of uction.
Preferably, the ~exible shaft has a plurality a~f articulately c~n ected sha segments. By providing a plurality of shaft segments, a unif~r torque ca be transmitted. Compared to known flexible shafts of spiral y ound wiry the flexible shaft of shaft segments has the advantage that n tching an a subsequent sudden free rotation of the drili~ head by the fl~xi 1e shaft r~
taxing can occur. With flexible shafts of spirally wound wire, a~ rrespondin torque can be built up by twisting the wire. W~ten the drill head is sudden!
released, the flexible shaft of twisted wire relaxes. Therebjy, he torque transmitted become nvn-uniform.
Preferably, a hose ~s provided In the shaft shaft having a pluraiit~r seg l rnents. The hose seals the inner channel of o against the flexible shaft ~ th washing channel, since drilled material could e een the btherwise get bj in dividual shaft segments and into the washing e the drilled channel. Furtl~

material could impair the flexibility of the e al accumu shaft if drilled ma~

' CA 02405193 2002-10-07 later between the individual shaft segments., With a reversed ranspart d -rection of the washing medium, i.e., if drilled material is disc' a ed throng the washing channel, the flexible shaft should be enclose y a hose avoid drilled material accumulations between the shaft segr~e~ts.
The washing unit, which is applied on the outsidea or of an ob a bon , preferably comprises a washing head, The flexibletoably held shaft is r i the washing head. The washing medium transportedd hrough outwa~ th inner channel of the flexible shaft, enters r m thei washing head If the inn r channel and is discharged therethrough. To i 1e this end, the fl shaft ha openings in the area of the washing head, whileg ead the washi . has a annular groove so that despite the rotation ft,he oiithe flexible sh~ washin medium and the drilled material can be dischargedi er from the chann I

into the annular groove and from there~outward.

i Preferably, the washing head is displaceably sjrpported in a g~i mg eiem~
of the washing unit. Thus, the contact surtace of the wash'i g unit can held Frrmly on the object or the bone and simultaneously se as a gui for the flexible shaft and the drill head. The flexible shaft is' h s guided the guiding element together with the drill head and the was in head so ,.
to make the bore in the object or the bane. ~ ' 'the flexible shaft preferably comprises a plurality of shaft seg ents. Ea shaft segment comprises at least one projection and a rec ass engaging recess or a projection of an adjacent shaft segment so that ro actions a~
recesses interlock. The dimensions of the projections and re a ses are a justed to each other such that a gap is formed that extends a a d the sha circumference. The interlocking projections and recesses of d acent shy segments are further designed such that they engage behind a ch other the longitudinal direction. Thereby, the shaft segmtnts are rmaneni connected in the longitudinal direction of the shaft. Due to th~ c rcumferen tial gap, a mutual play between the individual shaft segments i obtained Depending on the magnitude of the play and the length of ~he individual shaft segments, the shaft is more or less flexible, By rotating a shaft seg-ment connected to the drive, the gap between the shaft segm~n s is closed partly so that the opposing gap surfaces are partly in conta Power is transmitted via these contact areas from one shaft segment to t a next. In this manner, the flexible shaft transmits a torque. To trams it higher torques, the shape of the projections and recesses may be ~es gned such that contact areas as large as possible are obtained when rotatin the shaft.
The individual shaft segments are preferably 'hy inherently rigid, t are pref-erably made of hard plastic material or metal.and,, titanium.
especially Since the projection of one shaft segment engagese s into the re~ of an ad-jacent shaft segment, the projection engages , s behind the recess provided by the invention. Thus, the projection comprisels nd a neck-shape a head-shaped part. Similarly, the recess comprises a d ~ neck-shapedi a head-, sha h ed d art i are the The shaft se nt m eb tl p n cte p n . t r e g e s y permanen y cor longitudinal direction. The design of the projectionsesof the and recess pre-sent flexible shaft also serves to transmit e rtes.
traction and pressur The areas of the gap surfaces in which the shaft ach segments cont other when transmitting traction or pressure forces; lybe may preferab formed such that a transmission surface is formed to c pressure.
reduce the surfs Preferably, each shaft segment has at least fwo projections a d two re~
cesses on the shaft circumference. The surface for force trays lesion be-tween two shaft segments is thus increased. Preferably, the proj ctions are of the same size and are arranged regularly along the circum~er nce of the shaft. Thus, it is guaranteed that the flexible shaft has appr~xi ately the same flexibility in every direction of bending.
Preferably, the ratio between the gap width and the shaft dI~ eter is be-tween 1:100 and 1:10 for round shaft segments. This means ~h gap width is between 0.1 and 1 mm for a shaft diameter of 30 mm. This election of the gap width can influence the maximum possiblefa flexible bending Q

shaft. In order to increase the reliability of frques, the'transmission o as well as of forces, it is advantageous to providemII as gap widths as st possi-ble, i.e., a gap width of only 0.5 to 0.1 mm ~rf 10 mrn.
for'a shaft diamet To increase flexibility, not the gap width should~uthe num-be increased, ber of shaft segments by shortening the length alshaft of the individp seg-ments.
i In medical applications, the present core drill is~suitable not one y s an inter-medullary reamer, but also for loosening and washing out an ~ io clerosis as well as for removing nephroliths, uretheroliths and gallstones. T this avail, a gripping or catching device may additionally be provided at the drill head.
According to the invention, the broken stones afire carried awa~r b washing.
I
The above described core drill is not only suitableu oses, for medical ~ but for core drilling in general, where pressure h ad build-up at the drib is to be avoided. This is the case, far example, when ronding the material sut the i drill hole could be damaged by the pressure generatedd Iling.
upon The present drill is thus particularly suitable for C nd drilling soft plastic natural materials. Since no pressure is built up at the p esent drill head in th ,~ core drill, the drill is especially well suited for e ese brittle materials sin could be damaged by the pressure. For example, hairlined ccur cracks coul in the material. v The present core drill can be implemented bothlon d a large scale a in micro and nano technology. ~ ,~

After completion of the bore, material can be introduced into f~he drilled ob-jest through the inner channel of the flexible shaft. Thus, the d~(II d hole can be filled with filling material immediately upon withdrawing the rill, e.g. to stiffen the object.

In a preferred embodiment of the present invention, the flex~bl shaft itsel e can serve as a nail for connecting two bone pieces. To this erpd, the flexibh shaft is connected or adapted to be connected with a tensior~in device fo stiffening the shaft. The tensioning device w en doses the gaps bet the indi vidual shaft segments. Thus, the tensioning ~dvidual device pulls the i shaf segments together. Since the gap is designed g ntial such that to ~ force.

can be transmitted between the shaft segments, ~asegment;
pulling the s together forms a non-flexible tube, The same ke1y may be used di as a nai in a bone. Pulling together the individual shaftr a segments ma done, fog example, by means of a suitable cable control inthe or by compres flexible shaft. ' Preferably, the flexible shaft further comprises an anchoringld ice for an choring the shaft in the bone. Such an anchoring device is pr ferably de signed such that, when the flexible shaft is tensioned, ancho~in wedges a the like flip outward and cause the flexible shaft, now stiff ~ne to farm nail, to be anchored in the bone. Of course the anchorin ~an al g I so be ef fected before or after stiffening the shaft. Further, it is also pass ble to sepa rately introduce anGhvring elements into the inner channel iof the flexibly shaft and to insert them through corresponding openings in t a haft so tha an anchoring of the shaft in the bone is achieved thereby.
The blades of the drill head are preferably thdrill formed such thatj head as soon es it meets a harder sheath after drillinga real, soft core r~ is de flected back into the core material. Thus, it d iii emerge is avoided that the laterally from the object to be drilled, such as the bone. I
e The present invention for working on human and/ors e, exempla animal ti~

fled above by the core drill, is as well Suitable roscope for use as an a an endoscope. The present arkhroscope or endoscopee rises also coh a flexl ble shaft with an inner channel. The flexible d Ith a shaft is connect I work ing head with which tissue can be removed by Iiig, scrapini smoothing, m I

or the tike, for example. The working head has openings which cdmmuni with the inner channel. Further, the present arthroscope or erjdo~cope has washing unit. Corresponding to the above described core drily t a diametf of the working head, i.e. the maximum outer dimensions f t a workin head, which does not have to be a rotating tool, has to be 1 rg r than th outer diameter of the flexible shaft. Thus, a washing chann ' I l formed b the outer surface of the flexible shaft and a hole in the objet, .e. the h~
man tissue, for passing a washing medium therethrvugh. l In the present arthroscope, an additional working channel cou d a provide For example, optics could be introduced therethrough in ord ~ r t watch th working process. Further, washing filuid can b supplied through he workin channel which can then be sucked off through the working~l h ad and th washing channel between the flexible shaft end the inner all of the dri hole. l ' An arthroscope ar endoscope according to the;invention may,~e designed l a preferred manner corresponding to the abo~re described core drill.
The following is a detailed description of the lrwention with r~ fe ence to th accompanying drawings.
j In the figures:
Fig. 1 is a schematic side elevational view of the core drill, Fig. 2 is a schematic sectional view of the portion II in Fig:j 1, and Fig. 3 is a schematic sectional view of the pbrtion III In Fi~.
According to the (nventlon, the core drill can be used in pa is lar for cor drilling In a tubular bone 10, such as a femur . For this purpo e, the cor dri I
comprises a drill head 12 connected to a flexible shaft i4. A;sh~nk 16 co nests the flexible shaft 14 to the chuck of a drill, such as a pie matic drill, for example. The core drill further comprises a washing unit 1 for traps porting away the drilled material occurring in the area of th d ill head 1Z
using a washing medium. In the medical fleld,~the washing medi m prefera bly is a saline solution. In other technical fields gases or other ii aid media can be used as the washing medium. , y i The washing unit 18 comprises an connection 20 connected by a hose to reservoir containing washing medium. The' washing media is passe through a channel 24 provided in a guiding element 22 of th l w shing hea 18. From the channel 24, the washing medium is supplied to I~ c lindric cav ity 26 within the guiding element 22. From there, the washing dium flow into a washing channel 30 in the direction of the arrows 2~. he washin channel 30 is provided between an outer diameter d of the flex 1e shaft 1 and the bore diameter D (Figure 2). The bore diameter d comes onds to th drilling diameter D of the drill head 12. The washing mediu4m eaches th drill head 12 through the washing channel 10 and is guided a~o g blades 3 of the drill head 12. At the blades 32 of the drill head 12, the asking me dium receives drilled material. When drilling tubular bones, ~hi is primaril bone marrow. The bone marrow is carried away by the washi g edium. T
this end, the drill head has openings in the;form of longit di al slots 3 through which the washing medium can flowlinto the drill hea 12.
i The drill head 12 has a hollow interior so that?the washing m di m can flo through the slots 34 into the hollow interior 36 of the drill he d 2. from th hollow interior 36 of the drill head 12, the washing medium ~lo s in the d rection of the arrows 38 into an inner channel 40 formed in the flexibl shaft, The flexible shaft 14 is hollow along its entire length sQ t at the inn r channel 40 extends from the drill head 12 to the washing unit 1 . The was -Ing medium arid the drilled material flow thrdugh the inner ~h ne140 to washing head 42 provided In the washing unit 1$. J

The flexible shaft has a plurality of shaft segments 44. Each shift seg has a plurality of projections 46 engaging into recesses 48 of tie adj shaft segment 44. The projections 46 and the igned recesses 48 areide suc that the projections 46 and the recesses 48 ; ther engage behind ea h in tt longitudinal direction of the flexible shaft s gments 14. Thus, the shaft q are permanently connected in the longitudinaldirection.e to In or guarar tee the flexibility of the shaft 14, a gap Is thindividu formed between ~
l shaft segments 44 that extends along the entirea f circumferen the flee ble shaft 14. The width of the gap and the lengthdiidual of the i ~ sha segments 44 define the flexibility of the shaftn 46, 14. The projecti as w~

as the recesses 48, are preferably of the same r gularly size and ar~ a ranged on the circumference of the flexible isuarante~
shaft 14. Thug, itl that the flexibflity of the shaft 14 is the ' deflectio same in any directio o f=urther, the gap has a constant width in the i dion.
circumferential Since the washing medium could get into the el30 through washing chann the gaps between the shaft segments 44, wherebye al drilled ma~ could ge into the gaps and impair the flexibility of pishaft the shaft, the flexi 14 i;

lined with a hose 50. The hose 50 extends from a 12 the drill h to the shank 16.

The flexible shaft 14, via which the torque thdrift is transmitted fro to the drill head 12, is rotatably supported in the earings washing head 42 b 52 Further, to be able to pertorm a drilling, the ~ supporter washing head 4 f for displacement within the guiding element n f

2~ in the directio the arrov 55, i.e. in the direction of drilling. Preferably,ad42 fs the washing he cylin dricat so that it is displaceable in the cylindrice uiding cavity 26 of th ele ment 22. In order to avoid the washing head~42 g long from rotatiM whey drilling, the inner wall of the cylindric cavity ZG and the outer s dace of washing head 42 are provided with guiding eleiments. These rr~a be groa and corresponding projections. A seal Is provided between th~ otter sure of the washing head 42 and the surface of the cyllndric cavity X26 so as prevent washing medium from escaping outward from the cy in ric cavity passing the washing head 42.
The washing medium transported from the; drill head thr~u h the inn r channel 40 in the flexible shaft towards the, washing head 4 leaves th washing head 42 through a channel 54 and enters a hose 56~ico nected to collecting vessel. For this purpose, the washing head has an an ular groo a 58. Qn the level of the annular groove 58, the flexible shaft ~~4 omprises plurality of longitudinal slots 60 through which the washingl m dium flo s from the inner channel 40 into the annular groove 58. The has 56 is pre -erably connected with a suction device so that a vacuum is~cr ated at th drill head X2. This guarantees that no pressures occur in the or a of the dri I
head when drilling the bone i0 which could cause drill medi4m to be trap -ported, e.g. bone marrow being transported in venae. Thus,,~th risk of pul monary embolism caused by drilled material being transp~o ed into th Lungs is avoided. , l The inner side, in particular at the end facing the drill head ~.2 the flexibl shaft can have pro jections that cause the washing medium t rotate. F
example, these are blade-like projections. Further, a kind o chimedea screw may be provided. The inner side. of the ose 56 may al o a provide with a helical groove or a helical projection. Such elements c~u a the was ing medium to rotate and the transport of the drilled materiel l improved.
In the upper portion of the shank 16, the inner channel 40~of the flexi shaft 14 is sealed by a sea! 62 from the drill apparatus. t On the side facing the bone 10, the guiding element 22 of the ashing un has a contact surface 54 abutting the bone 10. By the contact urface, th washing unit 18 is sealed from the bone 10 soy that no or only 1I a washin medium can escape outward from the cyllndric cavity ~6 along the conta surface 64 and into the tissue surrounding the bone 10. In a~ld tion, wall ing medium is prevented from escaping along the contact surface 64 by pro-viding a suction device at the hose 56 so that no increased pros res occur in the area of the cavity 26.
In order to avoid the drib head XZ of the core' drill to penetr~ t the outer wall of the bone from the intermedullary space'of the bone 10 o ward, the blades of the drill head 12 are designed such that upon hitting h bone wall, i.e. harder material, from inside, the drill head 11z is deflected ba k into the intermedullary space. Thus, pertorating the bone, i.e. a lateralies ape of the drill head from the bane, is avoided..
This may also be achieved by providing a guide wire 66. The ~u de wire 66 extends through the shank 16, the hollow flexible shaft 14 andj th drill head iZ.
To effect a core drilling using ofdiameter a guide wire 66, he guide wire between about Z to 3 mm is first rig inserted throu h the bone. D the ~ sub-. 1lguided sequent drilling of the bone 10, by the drill head 12 is automatics the guide wire 66 so that the drillnot escape aly head 12 can lat from the bone 10. To make the bore in the ~ guide wireishus bone 10, th 66 intro-duced first. Then, the contact surtacee washing 8 is set G4 of th unit. onto the bone. Thereafter, the washing t a head 42 is introduced int cylindric i cavity 26 of the guiding element c ntacts 22 so that tine drill head i~ the bone i0 on the level of the contact a d surtace fi4.IThen, the drill I 12 is ro-tated by the drill ap aratus and a row moved in the direction of th~ 55 p to-gether with the flexible shaft i4 and the washring head 42.
The washing unit 18 may be designed such that it does not setv as a gul for the washing head 42. In this embodimen>a, the cavity 26~ is not seal from the washing head 42 but~from the outer surface of the ti xible sh 14. This is advantageous in that the guiding element 2Z does of have have the entire length of the bore. .
i

Claims

1. A device for working human and/or animal tissue, in particular an ar-throscope, an endoscope or a core drill, in particular an intermedullary reamer for tubular bones, comprising - a flexible shaft (14) with an inner channel (40), - a working head (12) connected with the flexible shaft (14) and hav-ing openings (34) communicating with the inner channel (40), and - a washing unit (18) with a contact surface (64) for a substantially sealed application on an object (10), - the diameter (D) of the working head (12) being greater than the outer diameter (d) of the flexible shaft so that a washing channel (30) is formed by the outer surface of the flexible shaft (14) and a bore made in the object (10), the washing channel serving to pass a washing medium therethrough.

2. The device of claim 1, wherein the washing unit (18) is connected with a suction device for create a vacuum at the working head (12).

3. The device of claim 2, wherein the suction device is connected with the inner channel (40) of the shaft (14) so that the washing medium is sucked off through the inner channel (40) together with the remove material.

4. The device of one of claims 1-3, wherein the flexible shaft (14) has a plurality of articulately connected shaft segments (44) and a hose (50) is provided in the flexible shaft (14).

5. The device of one of claims 1-4, wherein the washing unit (18) com-prises a washing head (42) in which the flexibie shaft (14) is rotatably supported.

6. The device of claim 5, wherein the washing head (42) is supported for displacement in a guiding element (22) of the washings unit (18).

7. The device of one of claims 1-6, wherein the flexible shaft (14) has a plurality of shaft segments (44) with mutually engaging projections (46) and recesses (48) which engage behind each other in the longitu-dinal direction, leaving a gap around the shaft circumference, so that the shaft segments (44) are permanently connected in the longitudinal direction having mutual play.

8. The device of claim 7, wherein all projections (46) are of the same size and are distributed regularly over the circumference of the shaft (14).

9. The device of claim 7 or 8, wherein the gulp has a constant width in the circumferential direction.

10. The device of one of claims 7-9, wherein the ratio of gap width and shaft diameter (d) is between 1:100 and 1:10.

ii. The device of one of claims 1-10, wherein the flexible shaft (14) is connected to a tensioning device for stiffening the shaft.

12. The device of claim 11, wherein the flexible shaft (14) his an anchor-ing device for anchoring the shaft in the bone.