AU670097B2 - Spinal therapy apparatus - Google Patents

Abstract

An apparatus comprising vertebral anchoring elements, e.g. a bone screw (1) or a hook (2), with a threaded cylindrical portion (5) and a locking plate (7). A nut (8) may be screwed onto the threaded cylindrical portion (5) to tighten the tightening portion of a slide (4) on a rigid connecting rod (3) with a circular cross-section. The rod (3), the slide (4) and the anchoring element (1, 2) may be sufficiently rigidly connected by means of non-slip projections on the engaged side of the locking plate (7), on the corresponding side of the slide (4), and on the surface thereof which surrounds the rod (3). The stiffness of the apparatus may thus be enhanced, whereby improved support of the vertebrae and easier fitting and adjustment of the apparatus may be achieved.

Description

OPI DATE 24/01/94 APPLN. ID 43330/9 11111lii1111IIfhlIIIIIIII AOJP DATE 14/04/94 PCT NUMBER PCT/FR93/0005 Illi1111ii 11 illli AU9343330 K f5(PG1) (51) Classification internationale des brevets 5 (11) Nuniero de publication internationale: WO 94/00062 A61B 17/58 Al (43) Date de publication internationale: 6 janvier 1994 (06.01.94) j. I t (21) Numniro de la demiande internationale: PGT/FR93/00605 (22) Date de dip6t international: l8juin 1993 (18.06.93) Donnies relatives Ai la prioriti: 92/07504 I9juin 1992 (19.06.92) FR (71)X72) D~posar.,s et inventeurs:. ROUSSOULY, Pierre ,R/ FR]; 53, aviri D 0 arh~my Bu~yer, F 69005 Lye'n (FRJ>s TAGLANG, Gilbert [FR/FR]; 9, rue Paul-Verlaine, F- 67370 Griesheim-sur-Souffel GROSSE, ArSe'ne [FR/FR]; 5, rue des Foug~res, F-67400 Illkirch-Graffenstaden CHOPIN, Daniel [FR/FR]; 66,-4*ocdu Tetteltiet, Stella, F 62780 Cicg (FR).'W (54) Title: SPINAL THERAPY APPARATUS (74) Mandataire: PONCET, Jean-Franqois; Cabinet Poncet, 7, chemin de Tillier, B.P. 317, F-74008 Annecy C~dex

(FR).

(81) Etats d~sign~s: AU, CA, JP, US, brevet europ~en (AT, BE, CH, DE, DK, ES, FR, GB, GR, TE, IT, LU, MC, NL, PT, SE).

Puhlike A vec rapport de recherche internationale.

6700972 (54) Titre: APPAREIL DE TRAITEMENT DU RACHIS (57) Abstract An app .,us comprising vertebral anchoring elements, e.g. a bone screw (1) or a hook 'h a threaded cylindrical portion and a locking plate A nut (8) may be screwed onto the threaded cylindrical portion to tighten the tightening portion of a slide on a rigid connecting rod with ai circular cross-section. The rod the slide and the anchoring element 2) may be sufficiently rigidly connected by means of non-slip projections on the engaged side of the locking plate on the corresponding side of the slide and on the surface thereof wh~nh surrounds the rod The stiffness of the apparatus may thus be enhanced, whereby improved support of the vertebrae and easier fitting and adjustment of the apparatus may be achieved.

(57) Abrege L'appareil selon l'inventiort comporte des 616ments d'ancrage dans les vert6bres du type vis osseuse ou crochet comportant une partie cylindrique filet~e et un plateau d'arr~t Un &crou peut se visser sur la partie cylindrique filet~e pour serrer une partie de serrage, d'un coulisseau engag6 sur une tige de solidarisation de section circulaire. Pour obtenir une bonne solidarisation de la tige du coulisseau et de I'0l6ment d'ancrage des reliefs antiglissement sont pr~vus sur ]a face d'appui du plateau d'appui sur la face correspondante du coulisseau et sur la surface du coulisseau entourant la tige On obtient ainsi une meilleure rigidit6 de l'appareil pour un meilleur maintien des vert~bres, et une plus grande facilit& de pose et de r~glage.

SP3INAL THERAPY APPARATUS -j 11FIELD OF THE INVENTION TChe present invention concerns a spinal therapy device [or treating a spinal column having an abnormal deformation as a result of degeneration or trauma.

The prior art includes many devices for treating 7.vertebral arthroses or fractures or fr cretn deformation of the vertebral column such as scolios-is, lordosis arid kyphosis.

For example, document tJS-A*4 648 388 describes a spinal therapy device having vertebral anchoring elements, a circular cross -sect ion fastening r'od with a smooth outside surface arid connecting Slides f or connecting the anichoring elements to the fastenling rod.

The anchoring elemefnrnts are screws with threo mrain parts, a helically threaded first end part adapted to penietrate arid to be held in the bonie, a -snaller diameter smooth cylindricaL inte--rmediate part, and a helically rthreaded second end peirt adapted to have a clamping nut screwed onto it. The Connectinog slides have a clamping part i shaped to surround a section of the fastening rod anid a connection part projecting laterally with two correspond iuig holes through which the anchor screw passes. The screw i s Cirst, screwed into the bone, after which the connecting slide is, fitted to the cylindrical intermediate, part o f the screw, anid finally the clamping nut is screwed onto the second threaded part of the Screw tp press the connecting z-lide against a vertebra and at the same time L~ cLamp the coninecting slide around the fastening rod.

A device of this kind is designed to mnaintain an appropriate curvature of the spinal column. 11owever, this device does not Provide tsuf ficient mechanical s:.upport. In particular, the direct bearing engagement off the slide on a vertebra rules out any possibility of 3 effective clamping because of the low mnechanical s'trenqth ___96-E9 99:8o 8T-TO-966T Z8 90 St OG EZ 133NOd 13N'I9E 3 %dX3 -2in compression of the vertebra. Also, fitting the device to a spinal column sometimes requires the simultaneous use of two tools, for example to prevent rotation of the screw when screwing on. or unscrewing the nut. Notches along the fastening rod reduce its mechanical strength and increase its flexibility. Also, this device is not compatible with three-dimensional reduction of the upper part of the spinal column, where screws cannot be inserted. Most importantly, the clamping force of the nut substantially increases the traction loading on the screw, combining with the forces retaining the fastening rod, which reduces commensurately the mechanical strength of the anchorage and promotes necrosis of the bone around the screw.

Document EP-A-0 408 489 describes a device for joining two vertebrae together by means of two double-threaded pedicle screws and two slides linked by a screwthreaded rod so that the distance between them can be adjusted. The screw has spherical bearing surfaces for adjusting the inclination relative to the slide, the tightening of a clamping nut onto the screwthreaded part of the screw preventing rotation. This device, which would appear suitable for adjusting the spacing of two consecutive vertebrae, is totally unsuited to supporting more than two vertebrae and there is no teaching as to the problem of insufficient mechanical retention of smooth connecting rods.

:SUMMARY OF THE INVENTION 20 It is an object of the present invention to overcome or substantially ameliorate ii at least one of the above disadvantages. i There is disclosed herein a device for treating a spinal column having an i abnormal deformation, comprising: a plurality of vertebral anchoring elements, each said vertebral anchoring element having a respective anchoring part shaped to be anchored in or on the bone of a vertebra and extended by a screwthreaded cylindrical part onto which a clamping nut is 4 .ewed; (N:\Iibttl00932:BFD' -3at least one fastening rod having a circular cross-section and a smooth outside surface; a plurality of connecting slides, each said connecting slide adapted to connect a respective anchoring element to a said fastening rod, each said connecting slide comprising a clamping part and a connecting part, said clamping part having inside surfaces shaped to surround a section of said fastening rod and being deformable for selectively clamping and releasing said slide from said fastening rod, said connecting part having a first branch and a second branch extending laterally and parallel to each other from two lips of a longitudinal slot in said clamping part, said branches of said connecting part having corresponding through-holes for receiving said screwthreaded cylindrical part of a said anchoring element for clamping said branches together and Sa thereby clamping said clamping part, wherein: each said anchoring element further comprises a locking plate with a bearing surface generally perpendicular to the axis of said screwthreaded cylindrical part and ;b extending from its base; said bearing surface of said locking plate including first non-slip projections, it and wherein: a corresponding first contact surface of said first branch of said connecting part is adapted to bear against said bearing surface of a said anchoring element, said first 20 contact surface comprising corresponding first non-slip projections to oppose any rotation and any lateral displacement of said connecting slide relative to said anchoring d element after clamping of said clamping nut against an opposite second contact surface of said second branch of said connecting part.

The invention has arisen out of the observation that supporting and positioning defects of prior art devices, combined with the relative complexity of fitting and adjusting them, are due to the possibility of pivoting either between the connecting slides and the fastening rod or between the connecting slides and the respective Sanchoring element. High rotation torques are generated on reducing deformation of the I [N:\libttIOO932:BFD' -4spinal column and consequently during supporting of the treated spinal column and the prior art devices are not able to withstand reliably these high torques.

The inside surfaces of the clamping part preferably include non-slip projections providing discontinuous bearing engagement opFosing rotation of the connecting slide around the fastening rod after clamping of the clamping member.

The non-slip projections are very effective in opposing rotation or sliding between the slides and the fastening rod and simultaneously between the slides and the anchoring elements, which movements occur immediately tightening of the clamping nuts is started. At the same time, the non-slip projections associated with the locking plate prevent rotation of the anchoring element during tightening of the nut even when the anchoring element is in the form of a bone screw, with the result that only one tool is needed to tighten the nut.

These arrangements also enable precise adjustment of the relative position of S the components, including accurate adjustment of the angular position of the connecting slides on the fastening rod and accurate adjustment of the angular position of the 1connecting slides on the a .:horing elements, by virtue of a locking effect before a complete tightening. i, By way of anchoring elements the device may include one or more doublethreaded bone screws on either side of an intermediate locking plate with non-slip i projections, one or more hooks whose rear wall provides a locking plate and includes non-slip projections, and possibly bearing plates shaped to match the specific i morphology of certain areas of the spinal column and including non-slip projections. i N t I F T 0 INAlibttl00932:BFD*

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5 BRIEF DESCRIPTION OF THE DRAWINGS Some preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: figures 1 and 2 are respectively side and front views of one preferred embodiment of a device; figure 3 is a perspective view of the device from figures 1 and 2; figure 4 is a perspective view of a bone screw that can be used as an anchoring element; figure 5 is a perspective view showing a pedicle hook which can be used as an anchoring element; Sfigure 6 is a perspective view of a lamina hook that can be used as an anchoring element; S. figure 7 is a perspective view of a connecting slide in a first preferred embodiment of the invention; figures 8 and 9 are respectively side and bottom views of the connecting slide from figure 7; figure 10 is a perspective view of a connecting slide in a second preferred embodiment of the invention; figures 11 and 12 show the connecting slide from figure 10 respectively in side 20 view and from below; figures 13 and 14 are perspective views of two other embodiments of connecting slides; figure 15 is a perspective view of a double connecting slide; rN Ot (N:\ltbtt100932:BFD' -6figure 16 is a perspective view of another embodiment of double slide; figure 17 is a perspective view of a sacral hearing plate that can be used as an anchoring element in implementation of the invention, figure 17A showing a similar illio-sacral bearing plate; figures 18 and 19 show the benefit of the sacral bearing plate; figure 20 and 21 are side and top views of a bearing plate adapted to bear on the body of a vertebra; figures 22 and 23 are respectively a side view and a top view of a spacer for linking two parallel fastening rods; and figure 24 is a perspective view of an end lamina hook.

DESCRIPTION OF THE PREFERRED EMBODIMENTS i: The device shown in figures 1 to 3 includes anchoring elements such as bone i t t t screws 1 or hooks 2, 102, 202, fastening rods 3 and connecting slides 4 between each anchoring element and the fastening rod 3.

The fastening rods 3 of the device of the invention are smooth rods with a circular cross-section. The material and the cross-section are chosen for optimum elasticity, matched to the loads encountered in use, and such that the rod can be curved to the required shape for the part of the vertebral column to be treated.

Each anchoring element, bone screw, hook or bearing plate is in one piece 20 with a screwthreaded cylindrical part 5 having an exterior screwthread 6 and includes a locking plate 7 limiting the clamping of a nut 8 onto the exterior screwthread 6.

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NL .t0 2 7 Inl tile figiure 4 emb~odiment the anchoring element is a double-threaded bone screw 1, the screwthreaded cylindrical part 5 with the exterior screwthread 6 cons t itut ing th e first screwthread, a screwthreaded coaxial cylindrical second part 9 constituting a second screwthread adapted to be screwed into the bone, the locking plate 7 constituting an intermediate part of greater cross-secbion between the two screwthreaded parts and 9. The lockino plate '7 advantageously has a faceted peripheral Surface 10 with six flats, an abutmenisurface 11 mnerging with the screwthreaded cylindrical second part 9 and ada~pted to bear against thle bone of Che vertebra, and a bearing suirface 12 generally perpendicular to tile axis I-1 of the screwthreaded Is cylindrical part 5 and extending fromt its base.

The bearing surface 12 of che locking plate_ 7 includes first noni-slip projections. For example, thf se first non-slip projections Carl be a granular suirface- or (preferably) radial ribs distributed over the bearing surface from the base of the screwthreaded cylindrical part 5. The screwthreaded cylindrical part 5 includes at least one intermediate arnular groove 13 constituting an area of weakness to facilitate separation of the excess part 14 after screwing a nut onto the screwthreaded cylindrical part 5. The groove 13 advantageously has a Sawtooth cross -section, the bottom of the groove being adjacent the remaining part of the scr'ewthreadcd cylindrical part tn the figure 5 embodiine~it the ;Lnchoring element is a pedicle hook 2 adapted to be hooked over the pedicle of a vertebra. The hook 2 has a. hook body 15, curved as I ,3hown i~n the figure, and a rear wall or bearing surface.

1.2 with which the screwthreaded cylindrical part: m C1r CJ C- The bearing surface 12 is qenera I ly perpendcicuilr Co the axis of the screwthreaded S 96-Eg 89:eO 8T-TO-966T Z8 90 St OG E .L30H08 ISNIEUJ 'cIX3 i f cylindrical part 5 and provides a locking plate. As i r the case of the pedicle screw in figure 4, the bearing surface 12 includes Eirst non-slip projections such as eadial ribs 16.

The figure 6 embodiment shot-s an anchoring eloment in the form of a lamina hook 102 Fshaped to be hooked over a vertebra laminia. The hook body IS is slightly different to that in figure 5. the other parts being identical, in parti ;ular the bearing surface 12 with the radial ribs 16 around the base of the screwthreadied cylindrical part In both the figure 5 and figure 6 embodiments the bearing surfaces 12 of the hook body 15 constitute che Locking plate of rthe anchoring element to limit clamping I S ot a~ nut onto the screwchreaded cylindrical part b..

In the embodiment of f igures 7 to 9 the connecting slide 4 of the invention has a clamping pi-rt 1.7 and a connecting part 18.

The connexting~ parr- E. 'ias a first branch 19 antd a second branch 20 which are generally flat with a gap 21 between them in the free scate; they extend laterally and p~iraltcl to each other from two lips of a longitudinal slot. '100 in the generally cylindrical clamping part 17 by which they are joined together. The clamping part 17 has ai generally cylindrical inside surface 22 defining a passage -5haped to surround ascino h atnn rod The cle-tiiping part 17 is deformable so that it can be clamped sdectively onto fie fiastening rod 3 or released there f rm.

Each of the branches '19 and 20 includes a respective through-hole 23 and 124, coaxiaL with eaclh.

other and having their common axis perpendicular to0 the axi~s of th(e inside surface 22 of the, clamping part 17.- The Lhrough-holoes 23 and '124 are shaped to recoive the ,,crewthreaded cylindrical part 3of an anchoring element.

S 96-E9 69:80 BT-TCOS66T Z8 GO GV OS i± I1N3wd .LBNIE03 -dX3 9 With substantial advantage the hole 124 could 'De CQplAced A by a slot enabling relative inclination of rhe slide during its titting to an anchoring element.

When the -,crewth'readed cylindrical part 5 of an anchoring element 1, P, 102 or 202 is insetted into the holes 23 and '124 of a slide 4 and the nut 8 is tightened until the two branches 19 and 20 are forced towards each other, the clamping part 17 is deformed and the diamer-er of the cylindrical inside sur ,ace 22 decrease--, s~o rhat it is clamped onto the rod 3. In this embodimenz. the anchoring eleme-nt is therefore also a clamping momiber.

Trhe inside surface 22 of the clamp-ing part 17 has second non-slip pro; ections opposing rotation of the connecting slide 4 ar'ound the fastening rod 3 acfer tightening tile clamping member. For example, the second non-slip projections are advantageously longitudinal ribs 24, preferably having a triangjular transverse crosssection, forming a discontinuous contact s~urface on the fastening rod .3.

At the time of use, the first contact surface 2S of the first branch '19 of thle connecting part 18 bears against thle bearing surface 12 of an anchoring element.

1I1his first contact surface 15"las also corresponding first nonslip projections similar to those on the bearing surface 1,2 of thle anchoring elemeat, in order to oppose any rotation and any lateral displacement of the connecting sLide -4 relati've to the anchoring element after tightening of thle nut 8 against the opposite contect surface 26 of the second branch 20 of, the connecting part 18.

.3 The first non-sip projections on the surfc are radial ribs 27, fo.: example, as shown in figures 8 and 9, surrounding the hole 23 which can adv!antageously have a shape complemenitary to that of thle radial ribs of the anchoring elements. The slide can therefore bC locked in various angular positions to the anchoring 4c/ 11* S 5'6-iES 00:60 ST-T0-G66T Z6 so 91' 09 ZSLD~ 3NBO'X 133NOd 13NIEV3 1dX3 I, element and this locking pre ven t.s o-tbsequent unintentional loosening of the nut~s 8.

Note th ,at in the embodiment shown the I first connecting br.inch 19 incorporating t he first contact surface 2~5 is offset outwardly relative to the axis 11-II of the clamping part '17 or the axis of thle ifltetrior cylindrical surface 22. Accordingly, the fas~tening rod 3 is slightly offset from the vertebra.

1i1 the embodiment of the invention shown in tigures '10 through 12 the connecting slide 105 is of the open type, having a generally rectangular parallelepiped shape and being slit axially by a slot 28 having a circular cross-section firsl, part, 29 throuigh which the fastening rod 3 passes and a smaller cross-section second IS part 30 ending at an enlargement 31. The slot opening~ .32 enables lateral. insertion of che fastening rod 3 whon the c:lamping member i~s released.

As in the previous embodiment, the slijde 109 ha, a first through-hole 33 and a second through-hole 31 in 2 0 corresponding relationship and shaped to fit to the scrowthreaded cylindrical part 5 of an anchoring element.

The first contact surface 25 has first non-slip projections such as radial ribs 27. The inside surface 22 of the t-xrst part 29 of the slot has second nion-slip pojections such as longitudinal ribs 24, ;advantacqeously having a triangular transverse cross -sect.ion.

heopen slide of figure 10 can be fitted to an intermediate part of the fastening rod 3, rather Ohan fitting it at one end thereof and sliding it into position.

Ifl the figj-lre 13 embodiment of the invention chv2 slide is similar to that of figures 7 through 9 with a clamping part 17, a connecting part 18, a first branch 19 anid a second branch 20 ,ic' th a respective hole 23 '5 cind 124. 1 r S% 9~ 6-9 00z60 Bl-TO-966T Z8 GO 09 ZZBNd.3N6O :X 133HOd 13HIEUJ :dX3 Hfowever, this embodiment o f the i rIveflt ion i s difterent in that the hole 23 in the first branch 19 is screwthreaded to receive the screwthreaded shank of a screw whose head bears on the edges of the smooth hrough-hole- 124 in the second branch 20, tho screw clamping the slide and locking it to the fasteni :j rod 3.

A second difference is that the first branch i9 ha s a lateral extension 34 with a hole 35 in it through which an anchoring element sliank passes. The hole 3 5 can advantageously have a hemispherical urpper surface 36 t~o recei.ve the hemispherical head of a conventional bone scr ew. The lower surface of the hole 35 can itself be flared, for example with a conical shape facing away from the hemispherical upper surface 36, to enable incliniation is of the shank oF the bone, screw relative to the axis of the hole 35. The bone screw can then assumec varioius inclinations, independently of the dire~ction of the axes of the hole 35 and of the cylindrical surface 22.

In this case a bone screw can inserted jnLo a vertebra after inserting it into the hole 35 in the lateral extension 34 after which a screw is screwed into the holes 23 and 124 until the branches 19 and 20 are moved towards each other and clamp the clampincg part 17 onto the fastening rod 3.

TIhe cylindrical surface 22 has longitudinal ribs as in the previous em)bodiments. [ikewisfz the first contact surface 25, or lower surface 6f the lateral extension 34, which incorporates non-slip projections such as radial ribs. It is to understood that a slide froin figure 13 can be used instead of the slides from figures 7 through 12, having the same rotation Preventing properties.

Figure 14 shows another embodiment of slide, simi Lar to that of f igure 13, with similar parts T identified by the same reference numbers. T'he difference is that the extension 37 of the first branch 19 extends S 96-E9 TO:60 ST-T0-G6&I z8 so St 09 ZE 133H~Od L3NIS'03 idX3 longitudinally rather than transversely, i.e. in the direction of the longitudinal axis of the cylindrical surface 22.

Figure 15 shows a double connecting slide 104 in which the first branch 19 of the connecting part '18 is in ono piece. The second branch 20 of the connecting part 18 is in two parts 120 arnd 220 between which is a transverse notch 320. Each part has its respc-'ctive through-hole 420 and 520 through which pass two clamping screws which are screwed into corresponding 8crewthreaded holes '119 and 2:j.9 in the Cirst branch 19. The figure ,ilide 104 is preferably longer han the slide in the previous embodiments, for example twice theijr length.

This version can be used to butt joint- two successive fastening rods for treating the spinal columin of a patient.

Figure 16 shows another embodiment. of doublesld which has the advantage of being open, incorporating a transverse slot 38 ending in two open cylindrical parts 39 and 40 each receiving one fastening rod. The slide is formed in two parts 41 *.nd 42 clamped togiy:ther by two screws 43 and 44 L-o be clamped onto two parallel fastening rod-s. TIo prevent rotation of the fastening rods the cylindrical surfaces 39 and 40 have longitudinal ribs, as5 shown in the figure.

Figure 17 s;hows another type of anchoring elemnent for implementation of the invention, namely a sacral bearing plate 50. A plate of this kind can be Used as an i.ntermediate support botween the vertebrae and a slide in the embodiments of figures 7 to 12, 13 or 14.- Trhe sacral bearing plate 50 is in the form of an elonclate plate having in its middle portion a screwthreaded cylindrical part 5 with ana exterior screwthread 6. One end 45 of the sacral bearing place is chicker anid includes a bore 46 shaped to receive the head of a t)T* S 96-ES Z0360 SB!-TO-966T Z8 go Gt OS LE .LBONOd .L3MIgUO2 :dX3 t 3 standard bone screw inserted in the pedicle, of the vertebra Si. The other end 47 of the sacral bearing plate includes two further bores 48 and 49 receiving thle head of standard bone screws inserted in the sacrumn.

S The upper surface of the sacral bearing plate A includes first non-slip projections such as radial ribs around the base of the screwthreaded cylindrical part and cooperating with the corresponding first non-slip prolections on the slides.

The axis of the bore 46 is. substantially perpendicular to the plane of the top and the boutom surfaces of the sacral bearing place 50 and substantially parallel to the axis of the screwthreaded cylindrical part 5. On the other hand, the respective axes of the 19 bores 48 and 49 are oblique, to orient the bone :,crews that they contain towards thle outside and so to facilitate Eixing of the sacral bearing plate onto tile alae o1 the sacrumn.

Thle sacral bearing plate S0 increases the spacing 2U between two successive slides 51 and 52 on the fastening rod 3, the first slide 51 providing the fastening to a first bone screw 53 inserted in Si via the sacral bearing plate 50 and the second slide 52 providing the connection with a second bone screw 54 inserted in L5. Accordingly, figure '18 shows a conventional. arrangement in which two bone sicrews 53 and 54 are joined together only by the slide-, 51 and 52, which are very close together on tile fastening rod 3. Their proximity makes it difficult to the screws and thie slides. Referring to figure 19, on the other hand, it 'Can be seen that the interposition of the sacraL bearing plate SO between the bone screw S3 and the slide 51 increases the distance between the slides 51 and 52, considerably facilitating the positioning of the components.

The dimensions of the sacral bear-ing pLate 50 atle _Z Z:60 BT-TO--S66T Z8 90 GS OS ZZ .L3flOd 13NIa'Uo :dX3 L 4 advantageously chosen so that the distance between the slides 51 and 52 is increased by about 15 mm.

F'igure hAsosan illio-sacral bearing pl>' 150 which has the same component parts as the sacral bearing plate 50 from figure 17, idenitified by the same reference numbers, -And additionally a lateral anchor lug 145 b~ent at right angle and having a lateral bore 146 shaped to receive a standard bone screw head.

Figures 20 and 21 show another type of anchoring I) element for implementation of the invention in the form of a bearing plate 56 adapted to bear on the body of a vertebra. The bearing plate 56 is a generally oval rigid place wh-ose opposed bottom atid top sirfaees 57 and 58 are curved to mate with the shape of the body of the vertebra. vie convex top surface 58 includes in its middle part. nonslip projections 59 and a cylindrical screwthreaded part for fitting a slide. The top surface 58 with its nonslip projectilons 59 constitutes a locking plate. i TIhe bearing plate S6 has uwo bores 60 and 61, one on each side of the cylindirical screwthreaded part 5, and both of generally heinispherical shape to receive the complementary hemispherical shape head of a standard bone screw. N~ote that the axes of the bores 60 and 61 are offset, as shown in figure 21, so that the bone screws 2 S enter the vertebra without. touching each other, despite the inclination of their respecuive axes.

Given that the device, of the invention can include two fastening rods 3 situated one on each side of th(e spinous process of the vertebrae, for better correction :3 0 and support of the spinal column of the patient, it can be advantageous to fasten the two rods 3 together by means of one or more 'transverse StiAbilising .,ystein* as shown in figures 22 and 23.

This stabilisinig system includes a spacer 62 having acntral part 63 ending in two wider end parts 4ad6 91# S 96-ZO Z0:60 8T-tO-G661 Z8 90 GS 09 Z .L33NOd. ILNIEg'D :dX3 each having a respctlive through-hole 66 and 67 and. a bearing surface 68 and 69 having first non-slip projections such as radial ribs 70 and 71. The holes 66 and 67 are preferably scrcwthreaded. The spacer 62 is connected to the fastening rods 3 by connecting slides whose first contact surfaces 25 bear on the ribbed bearing surfaces 68 and 69 of the spacer, preventing any rotation. Screws clamp each slide onto the corresponding surface 68 or 69 of the zspacer 62. in this way the dJistancia between the two fa~teriing rods 3 can be adju~ted by offsetting the slides relative to each other~ in the longitudinal directio:n, so that the spacer 62 assuimes an oblique position.

The device of the invention enables the use of a rod or of a plurality ot rod elements whose curvature is suited to the part of Lhe spinal colu-mn to be treated.

The slides 4 are easy to fit to the fastening rod 3 because they are threaded over each end of the latter, or engaged from the side, and slide freely on the rod 3 regardless of its curvature.

The deformacion of the spinal column is to be reduced in three dimensions. It is necessary to transforin a scoliotic curvature oriented in a plane close to the frontal plane into a physiological curvature in the sagittal plane and having a normal lumb~ar lordotic,K thoracic and kyphotic curvature.

Trhe fastening rod is first given a shape close to the normal. physiological curvature and positioned in the saggital plane of the patient, its two ends being fixed by means of anchoring elements and correctly clamped sl ides. The non-slip projections of the invention proidevey effective immobilisation of the rod, both i T~xi tranislation and, more importantly, i n rotation.

Anchoring elements area inserted in or on other S intermediate vert, brae. The anchorages nearest the rod S 96-Z9J ZO:60 8T-TO-966T, Z8 90 G 09 ZZ 130N0d 13N19VJ :dX3 16 are engaged in the slides and locked to jiunobil-ise Ltbrod in the saggital plane and also to prevent i t rotating. The most distant anchorages in the concave Part of the curvature can be engaged because of the lengthi of the screwthreaded cylindrical part 5 of (-he anchoring elements. once rhe end of the scre(Jeaed cylindrical part has been inserted into the bore of che connecting slide 4 fitted to the rod but not yet clamped onto the rod, progressi.ve tightening of the nut 8moves t he anchoraqve point towards the fastening rod, progressively reducing the vertebral curvature. Wller) the spinail column has no further elasticity, the lastcninq rod 3 is deformed and provides correction 1 n an intermediate position of maximal reduction.

iSThe device of the invention enable th e screwthreaded cylindrical part of each intermediate anchoring elemenL already fitted to be inserted into the bore of a slide and fixed rigidly to the rod, in alignment with anchor'inq elements above and below it, to achieve the required straightening of the vertebrae by screwing and tighl:ening of the nuts to lock the slides onto the rod.

The device of thie invention can be fitted either in f ront of or behind the spinal column of a paticnt.

PS Because of the non-slip projections the device of the invention can be fitted in a much shorter time ?Thani prior "art devices, cgiven the increased facility with which the surgeon can tighten or loosen the slide clamrfpinlg nuts 8 without modifying the penetration ot the bone screws into the bone.

It is to be Understood that a device of the invention can include screw, hook or plate type inchoring elements, depending on the treatment required, or a combination of any two or three of these types of a*nchoring eLement which-J are independent of each other.

tu E3T S 7'6-Z9J VO60 BT-TO-G661 ZS SO SG' OG Z ZLBONOd 13WIRU3 :dX3 Furthermore, the specific components (D C. he invention enable assembly of two opposed hooks associated with respective slides~ mounted on one and the s~ame Castening rod 3, to form a pedicle-lamina clamp. This is shown by the hooks 200 anid 202 in the upper part of che device shown ini figures I to 3. The pedicle hook 200 is shaped like the hook 2 shown in figure 5. Trhe hook 202 is ain end lamina hook as shown in figure 24, in which the hook--shape curved partL 203 is attached to a generally cubical body 204 through which is a transverse bore 205 for the fastening rod 3. A screw inserted inrco an aialt screwthreaded hole 206 bears on the rod passing; throuW;h the transverse bore 205 arid locks the hook 202 to the rod. The hook part 203 is near the axis of the fastening rod 3. The two opposed hooks 200 and 202 can be fitted so that one is in bearing engagement with the. pedicler and the other is in bearing engagement with the laina: of the same vertebra, cnorminej to the natural offset betweenJ the lainina. and the pedicle. Because of the rotatijonal locking of the pedicle hooks, procured by the no-.n-slip projections, part icularly effective attaChlunent is achieved to certain upper vertebrae, without using screw type anchoring elements.

It is to be uinderstood that a pedicie-- Lamina clainp of" this kind can be used independently of the presence or the nature of other anchoring elements, arnd that it has its owhn functions anid advantages.

rhe present invention is not limited to the emb~odiments explicitly described but encompasses various variants arid generalisations thereof within the scope of the following claim.o); 6T* S 96-ES GO:6O ST-TO-S66T ZS GO Gi' OS LE .3Nd±NS3:X

Claims (13)

1. A device for treating a spinal column having an abnormal deformation, comprising: a plurality of vertebral anchoring elements, each said vertebral anchoring element having a respective anchoring part shaped to be anchored in or on the bone of a vertebra and extended by a screwthreaded cylindrical part onto which a clamping nut is screwed; at least one fastening rod having a circular cross-section and a smooth outside surface; a plurality of connecting slides, each said connecting slide adapted to connect a respective anchoring element to a said fastening rod, each said connecting slide comprising a clamping part and a connecting part, said clamping part having inside surfaces shaped to surround a section of said fastening rod and being deformable for selectively clamping and releasing said slide from said tening rod, said connecting part having a first branch and a second branch extending laterally and parallel to each other from two lips of a longitudinal slot in said clamping part, said branches of said S connecting part having corresponding through-holes for receiving said screwthreaded eit: cylindrical part of a said anchoring element for clamping said branches together and thereby clamping said clamping part, wherein: each said anchoring element further comprises a locking plate with a bearing surface generally perpendicular to the axis of said screwthreaded cylindrical part and extending from its base; said bearing surface of said locking plate including first non-slip projections, and wherein: a corresponding first contact surface of said first branch of said connecting part is adapted to bear against said bearing surface of a said anchoring element, said first S' contact surface comprising corresponding first non-slip projections to oppose any rotation and any lateral displacement of said connecting slide relative to said anchoring i element after clamping of said clamping nut against an opposite second contact surface i 4 g 30 of said second branch of said connecting part. I

2. A device according to claim 1, wherein said first non.-slip projections comprise radial ribs respectively disposed on said bearing surface from the base of said screwthreaded cylindrical part and on said first contact surface from the edge of a said corresponding through-hole.

3. A device according to claim 1 or claim 2, wherein said inside surfaces of said clamping part comprise second non-slip projections opposing rotation of said R 4 connecting slide about said fastening rod after clamping of said clamping part. [NA\llbttlOO861: BFD' L -19-

4. A device according to claim 3, wherein said second non-slip projections comprise longitudinal ribs. A device according to any one of claims 1 to 4 wherein at least one of said anchoring element(s) comprises one or more double-threaded bone screws, said screwthreaded cylindrical part of a said anchoring element constituting a first screwthread, a coaxial second cylindrical screwthreaded part on the opposite side of said locking plate constituting an anchoring part with a second screwthread adapted to be screwed into bone.

6. A device according to any one of claims 1 to 5, wherein at least one of said anchoring element(s) comprises one or more hooks, wherein a hook body constitutes an anchoring part and wherein a rear wall of the hook, perpendicular to the axis of said screwthreaded cylindrical part, provides a locking plate and carries said first non-slip projections.

7. A device according to any one of claims 1 to 6, wherein at least one of said anchoring element(s) comprises a sacral bearing plate and/or an illio-sacral bearing plate, of generally elongate shape, comprising in its middle part said screwthreaded cylindrical part flanked by the bearing surface with first non-slip projections, and having in the vicinity of a first end a thicker part through which is a bore for a standard bone screw, and having near a second end two other bores for standard bone screws with the axis inclined.

8. A device according to any one of claims 1 to 7, wherein at least one of said clamping member(s) comprises a bearing plate adapted to bear ori the body of a vertebra, said bearing plate having a curved oval shape comprising said screwthreaded cylindrical part on the middle part of a convex side of said bearing plate, non-slip projections and, on either side of said middle part, two bores for bone screws with offset axis.

9. A device according to any one of claims 1 to 8, wherein at least one of said slides is a double connecting slide, wherein at least one of said branches of the connecting part has two parts separated by a transverse notch, and said part having i holes for clamping screws corresponding to screwthreaded holes on the other said y, branch, A device according to any one of claims 1 to 9, wherein at least one said connecting slide has two generally flat branches separate from each other and each merging with a generally cylindrical clamping part which links them together, and wherein: against said first connecting branch, including the first contact surface adapted to bear p xr; against the bearing surface of the anchoring element, is offset outwardly relative to the ^A i axis of said clamping part. 'i [N:\IibttOO861BFD' LC~ T, r

11. A device according to claA!' 10, wherein: said connecting branches of the coinnecting slide each comprise a single through-hole; and wherein said anchoring element is a double-threaded bone screw as defined in claim said bone screw simultaneously serving as a clamping part and an anchoring element.

12. A device according to any one of claims 1 to 9, wherein said connecting slide is of generally parallelepiped shape, said connecting slide being slit axially by a slot comprising a first part having a circular cross-section for a said fastening rod to pass through and a second part having a smaller cross-section, said second part ending at an enlargement, said slot opening enabling lateral insertion of said fastening rod when the clamping part is released.

13. A device according to claim 10, wherein: said first connecting branch, including said first contact surface, comprises a lateral extension or an axial extension not covered by said second connecting branch 0 15 and having a hole for a pedicle screw to pass through; and wherein th said second connecting branch includes a smooth through-hole for receiving the head of a clamping screw whose shank is screwed into a corresponding screwthreaded hole on said first connecting branch.

14. A device according to any one of claims 1 to 13, further comprising an assembly of two opposed hooks associated with respective slides mounted on the same said fastening rod, c!e said hook adapted for bearing engagement on the lamina and the other said hook for bearing engagement on the pedicle of the same vertebra.

15. A device according to any one of claims 1 to 14, comprising: two said fastening rods having respective anchoring elements and slides; and at least one spacer connected to each fastening rod by respective slides on which said spacei bears through surfaces with first non-slip projections. •16. A device for treating a spinal column having an abnormal deformation, substantially as hereinbefore described with reference to the accompanying drawings. DATED this Ninth Day of May 1996 Pierre Roussouly Gilbert Taglang Arsene Grosse Daniel Chopin N Patent Attorneys for the Applicant SPRUSON FERGUSON [N:\llbttl00861:BFD' rL L.