CA2076136A1

CA2076136A1 - Percutaneous fixation of vertebrae

Info

Publication number: CA2076136A1
Application number: CA002076136A
Authority: CA
Inventors: Parvis Kambin
Original assignee: Individual
Current assignee: Smith and Nephew Inc
Priority date: 1991-08-15
Filing date: 1992-08-13
Publication date: 1993-02-16
Also published as: EP0528562A2; EP0528562A3; JPH07178116A; US5242443A; AU650216B2; AU2072892A

Abstract

Abstract Of The Disclosure A method for percutaneous fixation of a pair of vertebrae of a patient, which comprises posterolaterally entering the back of a patient percutaneously with a plurality of pedicle screws, screwing each pedicle screw into the medullary canal of the pedicules of adjacent thoracic and/or lumbar vertebrae or the pedicles of the L5 and S1 vertebrae, to a position where the proximal end thereof lies adjacent the fascia of the patient; inserting pedicle screw linkages under the skin of the back of the patient and detachably securing the linkage means to the proximal ends of the screws on the same side of the spinous processes of the vertebrae to restrict relative movement between the vertebrae. A kit is provided for percutaneous fixation of vertebrae of a patient, comprising a plurality of pedicle screws of different sizes, yet of a size to enable the distal end of each screw to be screwed into the medullary canal of a pedicle of a vertebra with the proximal end thereof lying adjacent the fascia of a patient.

Description

207~136 The present invent~on relates ~o percutaneous interbody fusion Yith subcuta~eo~s internal fixators. ~ore particularly, the presen~ in~ention relates to percutaneous fixation of lumbar ve~tebrae by ~eans of a minimally in~asi~e technigue.
The u~e of internal fixators fmr fixation of unstable fractures of the vertebrae is Xno~n. also Xno~n is O a system for internal fixation of Yertebrae after the removal of one or more inter~ertebral discs. External fixation syste~s for the st~bilization o~ thoracic and lumbar fractures have also been proposed.
The use of existing I~ternal fixa~ors requires a large incision in the bac~ and dissection of the paraspinal muscles, Yhich is a highly in~asi~e procedure. I~ the internal fixators must be removed, a second major inYasive procedure is required. ~oreover, patients undergoing an internal fixation procedure r ~ re a lengthy O rehabili~ation, Lncluding reconditioning of the muscles.
The use of external fixators requires the patient to carry a fixation ass~mhly on the sl~face of ~he back, ~hich is difficult from a physical and psychological point o~ ~ie~ for a majority of patients. ~oreo~er, the rehabilit~tion of paraplegic patients ~it~ ex~ernal fixators ~as pro~en to be difficult.
In addition, external ~ixators have portals in the ski~ Yhich become sites for infection.

, There is thus a need ~n the art for skeletal fixation that can ~e performed with ~un~al injury to the muscular ligamentous structures.
There is also a need in the ~rt for a ~ethod of skeletal fixation vhereby the extraction of the ~ixators is accomplished Yith min~m~l surgical inter~ention.
There is a further ~eed ~n the art for a method of sXeletal fixation Yh~ch is acceptable both psychologically and cosmetically, and ~hich ~inimizes infection.
O The present invention provides a method for percutaneous fixation o~ ~ertebrae of a patient, ~hich comprises pos~erolaterally entering the back of a patient percutaneously ~ith a plurality of pedicle scre~s, scre~ing each pedicle screw into the medullary canal of the pedicles of adjacent thoracic and/or lu~bar ~ertebrae or the pedicles of the 15 and Sl ~ertebrae, to a position Yhere the proximal ends of the screvs lie adjacent ~e fascia o~ the patient:
inserting fir~t and second pedicle scre~ linkage _eans under the skin of the ~ack of the patient and detachably securing the linXage means to ~e proxi3al ends of said screvs on the came side o the spinous processes of sai~ vertebrae to restrict relative movement between the vertebr2e.
As can be seen, the method of the present invention requires only a s~all incision to enable the ; surgeon to link the pedicle screYs together. ~he fixators are located internally, thereby a~oiding the disadvantages of external fixation. Since the subcutaneous i~ators used in ~he present in~ention may ~e re~o~ed routinely after a period of rehabilitation, such as from 10 to 12 Yeeks, future MRI and CT ~isualization of the spinal canal and the lateral recesses are then possible. In contrast, the permanent implantation of internal fixators preventç the use of ~RI and c~ ~isualizations.
The present Lnven~ion further provides a kit for percutaneous ixation of vertebxae of a patient, c~mpr~sing 3 a plurality of pedicle scre~s of different sizes, yet of a size to enable the distal end of each screw to be screYed into the medullary canal o each pedicle of a vertebra ~ith the proximal end thereof lying adjacent the fascia of ~
patient. The kit may include a plurality of linkage means !5 proportioned to lie ~Lnder the skin of the patient and operab~e to detachably link together the prox;~al ends of the pedicle screws inserted into the pedicles of the ~ertebrae.
The present ~n~ention is illustratPd in t~r~s of ~0 its preferred ~mhodi~ents in the accompanying draYLngs ~n ~hich:
Fig. 1 is a schematic vie~, partly in section in enlarged scale, of one of the pedicles of a lumbar ~ertebra into ~hic~ has been inserted a pedicle scre~ ~ith a ~eam member detachably linked to the pedicle screY;

207613~

., Fig. 2 ~s a schematic ~ieY, in enlarged scale, shoYing t~e su~cutaneous fLxati~n syste~ of the present in~ention ~ lanted in a patient;
Figs. 3-8 are elevational ~ieYs o~ Yarious instruments used to perform Ih~ surgical procedure o4 the present invention;
Fig. 9 is a plan ~ie~ of a kit for carrying out the method of the present in~ention;
~ig. lo is an ele~ational ~ie~ o~ a tool used to 3 carry ou~ the method of the present in~ention; and Fig. 11 is a ~iew i~ perspective of an alternati~e embodiment of the present invention.
~ig. 1 schematically shovs a pedicle scre~ 1 Lnserted into the medullary canal 2 of the pedicle 3 o~ a ; lumbar vertebra 4 of a patient. The distal end la of ~he pedicle scre~ 1 extends into the body 5 of the vertebra ~, w~ile the proxLmal e~d lb lies ad~ace~t to the lumbar fascia 20 (sho~n in phantom line). Fastened to the proximal end lb of pedicle scre~ 1 is an adaptor 6 having a slot 6a therein ; for receiving a beam member 7, here shoYn in the form of a pla~e. ~ig. 1 shovs the pedicle screv 1 inserted into the pedicle 3 situated to one side of ~he spinou~ process tnot shown) of the ~ertebra 4. In the same manner, the pedicle (not sho~n) ly~ng on the other side of the spinous process is also provided ~ith a pedicle scre~ and an adaptor. The intervertebral disc ~o be rem~Yed lies bet~een the ~ertebra , 4 shown in Fig. 1 and a lumbar ~ertebra adjacent ~hereto (Fig. 2), Yhic~ is also pro~ided with pedicle screYs inserted in t~e pedicles thereo~, adaptorc fastened to the proximal ends of the pedicle screYs, and a bea~ ~e~ber in S the same manner as shoYn in Fig. 1.

Fig. 2 is a schematic ~ie~ o~ the asse~bly of pedicle screws, adaptors and beam members of t~e lnvention, as vie~ed posteriorly Yi~h part of the skin 30 and subcutaneous tissue 40 of the patient removed for ease of o illustration. ThuS, pedicle screvs 1 are ~eld in the one ~air of the pedicles (not s~oYn~ of lum~ar vertebra La, ~hile ~he other pair of pedicle scre~s 1 is held in t~e pedicle o~ vertebra Lb ;mmedia~ely above or beloY lumbar vertebra La. ~he interver~ebral disc D to be remo~ed is betYeen lumbar vertebra La and Lb as schematically indicated. All of the adaptors 6 are preferably flush against ~he lumbar fascia 20 as sho~n ~n Fig~ 1. Pedicle screYs 1, adaptors ~ and be~ ~embers 7 are all made of biocompatible material, ~uitably s~ainless steel.
~h~ s~rgical pro~edure for percUtaneous fixation of l~mbar ~ertebra of the invention ~ay be carried out as follovs. The patient is placed prone on a radiolucent table and frame ~not shown). The C-arm of a conventional fluoroscope is positioned for anteroposterior visualization of the lumbar vertebrae and t~e table is tilted away fro~
~he C-arm to permi~ better lnc~-ization of the pedicles. A

2~76136 cannulated tubul~r guide 8 (Fig. 3) is m2neu~ered by hand or by the flexible holder 9 (Fig. 4) havang its proxi~l end 9a secured to t~e table and carrying at its distal end a ring 9b ~or holding guide 8. The guide 8 is ~ane w ered ~ith the hol~e~ g until the guide 8 is aligned Yith the longitudinal axis of the pedicle, after ~hich the holder 9 is locked into place. When properly aligned, the guide 8 ~ill appear by fluoroscopy as an opague circle irt the center Or the pedicle. A guide vire (not shoYn), suitably o~ 2m~ outside diameter, ic introduced into the guide 8 and is ad~anced through the skin of the patient's bac~, posterolate~ally toward the pedicle 3. The guide ~ire is tapped Yith a ~allet into the cortical bor.e at the junction of t~e base of t~e transverse process lo (Fig. 1) and the proxL~al articular process 11. After removal of guide 8, a cannulated obturator 11 ~Fig. ~) hav~ng a lumen lla is placed over the guide vire and ad~anced through the skin of the patient's bac~ to the pedicle 3, ~olloved by placing an access cannula 12 (~ig. ~) over ~he obturator 11, and ad~ancing the cannula 12 to the pedicle 3~
The obturator 11 is then removed, and a cannulated drill 13 having a lumen 13a (Fig. ~) is placed over the guide vire and ad~anced to the pedicle 3. By ~ually operating the arill 13, the opening o~ the cortex of the pedicle is enlarged to form an entrance 3a (Fig. 1) into the medullary canal 3b of the pedicle 3. The cannulated drill 207613fi 13 is removed and a blu~t end pedicle scre~ probe 14 (F~g.
8) is manually ad~anced into the ~ dullary canal 3b ~ith a twisting motion, to crush the cancellous ~one of the medullary ~nal 3b thus creating a t ~ el or bore 3c ~ig.
1) eYtending from the pedicle 3 into the Yertebral body 5 (Fig. 1). ~he probe 14 or a bl~nt end R- ~ can be i~serted into ~he ~ore 3c, the posîtion and length of the probe or R-~ire bei~g checked by anteroposterior and lateral fluoroscopy.
If desired by the surgeon, the bore 3c ~ay be tapped to receiYe the thr~ads lc of the pedicle screw 1.
Alter,nati~ely, a self-tapping pedic~e screv ~ay be used.
Before impla~t~ng the pedicle screY 1~ the bore 3c may be inspected ar~hroscopically to make certain that the cortex 3d tFig. 1) of the pedicle 3 has not been Yiolated: if it has been, the surgeon may abort the procadure.
~ he length of the pedic}e scre~ 1 ~o be used ~ay be determined by ~he u~e of a X-vire. ~us, the g-vire can be used to measure the depth o~ bore 3c, and ~e distance ~et~een t~e bone and the lTm~ fascia 20.
The appropriate pedicle scre~ 1 is selected from the kit S0 ~Fig. 9) containing a plurality o~ pedicle scre~s 1, beam members 7 and adaptors 6 in a container 51. The pedicle screw~ 1 are all of a size to enable the distal end la of each screY 1 to ~e screYed into the medullary canal 3b of ~he pedicle 3 of a lumber ~ertebrae Yith the proximal end 20761~6 Ib thereof lying adjacent the lumbar fascia 20 of a patient, while the beam members 7 are proportioned to lie under the skin 30 of the patient and operate to detachably link together the proximal ends Ib of a pair of pedicle screws 1 (Fig. 2) inserted into the pedicles 3 o~ the lumbar ~ertebrae.
Generally, the pedicle scre~s 1 in kit 50 ~ill be of different lengths and diameters. ~owever, it is conte~plated ~hat the kit may contain pedicle scre~s 1 of different l~ngths and the sa~e diameters. Moreo~er, while ~he beam members 7 may o~ dif~erent lengths, all sized to be received in adaptors 6, some beam m~hers 7 in the kit 51 may be much longer and will be cut to length by ~he surgeon.
Adaptors 6 will comprise adaptors ~aving a slot 6a open a~
one end and closed at the other, such as the upper adaptors 6 as viewed in Fig. 2, ~hile others will ha~e a slot 5a open at both ends, ~uch as the lo~er adaptors 6 as viewed in ~ig. 2.
The pedicle screw 1 selected is placed into the access cannula 12 and thence into the bore 3c. An allen wrench (not shown~ may be inserted in~o the recess ld ~Fig.
1), to drive the pedicle screw 1 i~o the bore 3c. ~owever, pedicle screw 1 may be pr~vided ~i~h any suitable means for engaging a pedicle screw driver, such as a slot in screw 1 and a corresponding blade for the driver.

2~76136 After pedicle screv 1 is i~planted, an a~aptor guide 15 (Fig. 10) ha~ing an outside diameter smaller than the inside diameter of the tubular body 6~ is inserted through the access cannula 12 so that the projecticn 15a enterS reCess ld (Fig. 1), after ~hich the accesn can~ula 12 is removed. An adaptor 6 is slid over the adaptor guide 15 and is scr~ed ~n place over the external thread~ on the proximal end Ib of screY 1, to the position shovn ~n Fig. 1.
All of the aaaptors have an ~nternally threaded tu~Glar body 6~ extending from a slotted cap 6c, ~he slot 6a ly ~ in a plane perpendicul æ to ~he tubular body 6b. Adaptor guide 15 m~y also be used as ~ driver for the pedicle screvs, for exzmple ~y providing a slot ~not sho~n~ i~ the distal ~nd of guide 15 to receive a cross-bar that serves as a habdle.
After the pedicle screvs are in place, ~he disc D
is removed by percutaneous total discecto~y. Sae, e.g., .S. Patents 4,573,448, 4,545,374 and 4,678,459. Bone gra~ts are then pac~ed bet~een the vertebral plates, and the vertebrae are aligned into their desired position by compression, extension and/or a~gUlation using a vre~c~ (~ot shovn) or other tool th2t securely g.rasps the pro~i-al ends lb of ~he screYs and~or the adaptorc 6.
When the ~ertebrae are properly aligned, they are locked in place by insert~ng the beam mem~ers 7 into the adaptors 6 a~d, in turn, locki~g the beam ~emberc 7 in place. Thus, one end o~ the beam member 7 is recei~ed in an -- , o--adaptor 6 ha~ing a slot 6a op~n at one end and closed at the other, such as the upper adaptors 6 sho~n in Fig. 2, while the other end is received in an adaptor 6 having a slot open at both ends, such as t~e lower adaptors 6 shown in Fig. 2.
S To insert the ~eam member 7 i~to the adaptors 6, a small incision (not shown), may~ if necessary, be made in the patient's back ad~a~ent the adaptor 6 having a slot 6a ~av~ng two open ends. ~e beam memher 7 is inserted into the subcutaneous tissue 40 via the incision and advanced through adaptors 6 until the distal end of t e beam member 7 contacts the closed end of adaptor 6. If necessary, the bea~ memhers 7 may be bent to allov the beam m~mher 7 to be received by the adaptors 6. Eac~ beam member 7 is locked in place in adaptors 6 by set screws (not shown) or by crimping the adaptors 6 and ~he ends of the bea~ member 7 or by any other suitable detachable locking means. The incision is then closed.
It is presently preferred that the adaptor cap 6 have a lo~ profile, i.e. with a small thickness relative to its length and width. Preferably the cap 6c has a su~stantially flat top and flat underside as shown, but other configurations may be used as long as the cap 6 is proportioned to lie beneath the skin of the patient without ; substantia}ly violating ~he skin and/or the lumbar fascia20. Thus, i~ ~he beam members ~ are in the form of rods 16 tFig 11), the cap 6 ~ay still ~e flat but a suitable cylindrical slot (not sho~n) ~ill be used.
Suitably, the guide Yire ~ay be about 10 to 12 inches long ~hile the cannu}ated obturator 11 may be about 6 to about 7 inches long and about 7~ Ln dia~ete~, ~ith a lu~en lla sized to slide over the guide ~ire. The acce~
cannula 12 ~ay be about 5 to about 6 inches long ~ith an i~side diameter of about 7r~. The cannu~ated drill 13 also has a lumen 13a sized to slide o~er the guide vire and vill have an outside diameter somewhat snaller than the outside diameter of the pedicle screw.
The pedicle screw 1 may have an outsiae diImeter o~ about 5 to about 6.5m~ and ~ay s~itably be fro~ about to about 70mm Ln total length, vith a dista} portion lc of ; about 20 to about 45~m carryin~ a ~one screv in thread form arld ~he prox~al portion being threaded to receive the adaptor 6. $he tubular body 6b of the adaptor 6 m~y be about 1~ to about 30~m long, ~ith a cap 6c of about 30x30~m square and about 4 to lOmm thick. The slot 62 must acco odate the be~m member 7. ~lates of about 5 to about lOm~ Yide by about 3 to about 90mm long are suita~le, the thickness o~ the plates 7 being about 2 to about 5mm. Rods 16 of about 5 to about 7~m ~n diameter and 35 to about 50mm long are also suitable. Anatomical ~ariations of a particular patient ~ay re~uire the use of different dimensions.

While the draYingS shoY for convenience the fixation of only t~o vertebrae, it is to be understo ~ that more than ~vo vertebrae may be fixed. For e~a~ple, ~hen t~o intervertebral discs are to be remove~, say bet~een vertebrae L1, I2 and I3, pedicle scre~s 1 Yill ~e i~planted in the pedicles of the three ~e ~ rae. ~he pedicle screYs rising from the .1 or I3 vertebra ~ill carry an adaptor 6 ha~in~ a slot closed at one end, ~hile the other pedicle scre~ ~ill carry an adaptor ~ ha~Lng a slot open a~ ~oth 10 ends. A longer beam me~ber 7 is then slid through the adap~ors 6 and locked ~to place as described abG~e. Hore-over, t~e surgeo.~ may elect to ~ix three vertebrae even i~
only one disc is to be removed.
While the present in~ention has been illustrated in the accompanying dra~ings in terms of the fixa~ion o~
adjacent lumbar vert~brae, it is to be understood that the same proced~res are folloYed for the fixation of adjacent thoracic verte~rae, of adjacen~ thoracic and lumbar verte~rae and of the L5 and Sl ~ertebrae. In each case, the 20 procedure is effected percutaneously as described abo~e.
T~at is, the center of ~ach pedicle to ~e inplaDted ~ith a pedicle scre~ is located f~uoroscopic ~ly, the pedicle screvs ~ e ~ planted perc~taneously as described above and ~he proximal ends of the pedicle scre~s are linked ~ogether 25 beneath the skin at or pre~erably flush with the ~uscle ~ascia as described abo~e. If considered desirable by the surgeon, the beam m~ers and/or the pedicle scre~s ~ay be cross~ oge~er, such as by t~e use o~ 1.5m~ cross-~ires.
Xoreo~ter, v~le the kit So is illustrated as co~taining the scre~s, beam me3~lbers and adaptors, t.he same or auxilia~y kits may be provided Yit~ t~e instn~e~ts used to carry out t~e surgic:al procedure, suc~ as ~e instruments sho~n in ~igs. 3-8 and 10.

Claims

1. A method for percutaneous fixation of vertebrae of a patient, which comprises posterolaterally entering the back of a patient percutaneously with a plurality of pedicle screws, screwing each pedicle screw into the medullary canal of the pedicles of adjacent thoracic and/or lumbar vertebrae or the pedicles of the L5 and S1 vertebrae, to a position where the proximal end thereof lies adjacent the fascia of the patient; inserting first and second pedicle screw linkage means under the skin of the back of the patient and detachably securing said linkage means to said proximal ends of said screws on the same side of the spinous processes of said vertebrae to restrict relative movement between said vertebrae.

2. A kit for percutaneous fixation of vertebrae of a patient, comprising a plurality of pedicle screws of different sizes, yet of a size to enable the distal end of each screw to be screwed into the medullary canal of a pedicle of a vertebra with the proximal end thereof lying adjacent the fascia of a patient.

3. The kit according to claim 2, wherein said pedicle screws are of different diameters.

4. The kit according to claim 2, wherein said pedicle screws have distal portions carrying bone screw threads of different lengths.

5. The kit according to claim 2, including a plurality of linkage means proportioned to lie under the skin of the patient and operable to detachably link together the proximal ends of said pedicle screws inserted into the pedicles of said vertebrae.

6. The kit according to claim 5, wherein said linkage means comprises a plurality of beam members and a plurality of adaptor means for detachably securing said beam members thereto, said adaptor means being detachably fastenable to said proximal ends of said pedicle screws.

7. The kit according to claim 6, wherein said adaptor means comprise a slotted cap and a tubular body extending therefrom, said slot lying in a plane perpendicular to said tubular body, each of the slots being proportioned to receive a beam member, some of the caps having a slot open at both ends and others having a slot open at one end and closed at the other.

8. A pedicle screw for percutaneous internal fixation of vertebrae, which comprises a screw having proximal and distal ends and a size to enable the distal end of each screw to be screwed into the medullary canal of a pedicle of a vertebrae with the proximal end thereof lying adjacent the fascia of a patient.

9. The pedicle screw according to claim 8, wherein the distal portion thereof carries a bone screw thread.

10. The pedicle screw according to claim 8, wherein the proximal portion thereof carries means engageable with a pedicle screw driver.

11. A method for percutaneous fixation of a pair of lumbar vertebrae of a patient, which comprises posterolaterally entering the back of a patient percutaneously and forming an opening in the cortical bone of each said pair of lumbar vertebrae at the juncture of the base of the transverse process and the proximal articular process of said vertebrae, said openings providing entrances into the respective medullary canals of the pedicles supporting said processes; percutaneously screwing into each of said medullary canals a pedicle screw to a position where the proximal end thereof lies adjacent the lumbar fascia of the patient, providing for each pedicle screw an adaptor having a slotted cap and a tubular body extending therefrom, said slot lying in a plane perpendicular to said tubular body; fastening the tubular body onto the proximal end of each said pedicle screw such that said adaptor cap lies between the lumbar fascia and skin of said patient; sliding a beam member under the skin and into the slots of said caps; and detachably locking said beam members to said caps.

12. The method according to claim 11, wherein said vertebrae are aligned before insertion of said beam members, said beam members being locked in place to maintain said alignment.

13. The method according to claim 11, wherein the slot of one of said caps is open at both ends while the slot of the other said cap is open at one end and closed at the other, said beam member being slid through said slot of said one cap into said slot of said other cap.

14. The method according to claim 11, wherein each said opening is formed by locating the position of said opening fluoroscopically, posterolaterally introducing a guide wire through the skin of the patient's back and advancing said guide wire to said location and into said cortical bone at said junction; sliding a cannulated obturator over said guide wire and advancing said obturator to said junction; sliding an access cannula over said obturator and advancing said cannula to said juncture;
removing said obturator; forming said opening with a pedicle cannulated drill means inserted in said access cannula over said guide wire and thereafter removing said guide wire and said drill means.

15. The method according to claim 13, wherein a blunt end member is inserted in said access cannula and advanced into said medullary canal to crush cancellous bone therein and thereby form said medullary canal bore.

16. The method according to claim 15, wherein said pedicle screw is screwed into said medullary canal bore via said access cannula, and said access cannula is removed.

17. The method according to claim 15, wherein said pedicle screw has at its proximal end means for engaging a pedicle screw driver, said driver being introduced into said access cannula, said pedicle screw being screwed into said medullary canal bore by screw driver.

18. The method according to claim 16, wherein said adaptor is fastened onto said proximal end of said pedicle screw.

19. The method according to claim 18, wherein said adaptor is screwed in place onto said proximal end of said pedicle screw.

20. The method according to claim 18, wherein said adaptor cap is substantially flat and is fastened flush against the lumbar fascia of the patient.

21. The method according to claim 18, wherein the intervertebral disc between said vertebrae is removed and bone grafts are implaced before said beam members are inserted into each pair of associated adaptors and locked into place.

22. The method according to claim 11, wherein said beam member is a plate or rod.

23. The method according to claim 1, wherein said pedicle screws are implanted in the pedicles of adjacent thoracic vertebrae.

24. The method according to claim 1, wherein said pedicle screws are implanted in the pedicles of adjacent lumbar vertebrae.

25. The method according to claim 1, wherein said pedicle screws are implanted in the pedicles of adjacent thoracic and lumbar vertebrae.

26. The method according to claim 1, wherein said pedicle screws are implanted in the pedicles of the L5 and S1 vertebrae.