CA2149322A1 - Pedicular screw and posterior spinal instrumentation - Google Patents
Pedicular screw and posterior spinal instrumentationInfo
- Publication number
- CA2149322A1 CA2149322A1 CA002149322A CA2149322A CA2149322A1 CA 2149322 A1 CA2149322 A1 CA 2149322A1 CA 002149322 A CA002149322 A CA 002149322A CA 2149322 A CA2149322 A CA 2149322A CA 2149322 A1 CA2149322 A1 CA 2149322A1
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- Canada
- Prior art keywords
- screw
- pedicular
- instrumentation
- grip
- screw thread
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/70—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
- A61B17/7074—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling
- A61B17/7076—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling for driving, positioning or assembling spinal clamps or bone anchors specially adapted for spinal fixation
- A61B17/7082—Tools specially adapted for spinal fixation operations other than for bone removal or filler handling for driving, positioning or assembling spinal clamps or bone anchors specially adapted for spinal fixation for driving, i.e. rotating, screws or screw parts specially adapted for spinal fixation, e.g. for driving polyaxial or tulip-headed screws
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/70—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
- A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
- A61B17/7002—Longitudinal elements, e.g. rods
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/70—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
- A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
- A61B17/7032—Screws or hooks with U-shaped head or back through which longitudinal rods pass
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/70—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
- A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
- A61B17/7041—Screws or hooks combined with longitudinal elements which do not contact vertebrae with single longitudinal rod offset laterally from single row of screws or hooks
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/70—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
- A61B17/7049—Connectors, not bearing on the vertebrae, for linking longitudinal elements together
- A61B17/7052—Connectors, not bearing on the vertebrae, for linking longitudinal elements together of variable angle or length
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/70—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
- A61B17/7055—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant connected to sacrum, pelvis or skull
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/88—Osteosynthesis instruments; Methods or means for implanting or extracting internal or external fixation devices
- A61B17/8875—Screwdrivers, spanners or wrenches
- A61B17/8886—Screwdrivers, spanners or wrenches holding the screw head
Landscapes
- Health & Medical Sciences (AREA)
- Orthopedic Medicine & Surgery (AREA)
- Neurology (AREA)
- Surgery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- Public Health (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Engineering & Computer Science (AREA)
- General Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Veterinary Medicine (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Neurosurgery (AREA)
- Surgical Instruments (AREA)
- Prostheses (AREA)
- Amplifiers (AREA)
- Measurement Of Force In General (AREA)
- Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
Abstract
The instrumentation comprises for each lumbar vertebra (L5), two pedicular screws (1) having two screw threads (9, 11), one (9) of the screw threads corresponding to the region of penetration of the screw in the pedicle, two rods (2) having asperities respectively associated with a pedicular screw and secured to the latter by connection elements (3) provided with elements for clamping the rods. Each connection element (3) is in one piece and the screw thread (9) corresponding to the region of penetration of the screw in the pedicle terminates in an annular shoulder (16) against which the connection element bears which is separated by a smooth part (15) from the screw thread (11) outside the region of penetration in the pedicle. This instrumentation permits both returning the slipped vertebrae rearwardly and pivoting it in the desired direction of rotation, it being possible to carry out the derotation action slowly and by controlling the movement so that the surgeon achieves on the whole in the two movements an excellent precision in the repositioning of the vertebrae relative to the neighbouring vertebrae.
Description
~:`*
`' W~ 94/1~28 2 1 4 9 ~ 2 2 ~cr/US93/10966 ~.. . ..
.
PEDlCULAR SCREW AND POSTERIOR SPINAL INSTRUMENTATION
. , `' The invention relates to lumbar osteosynthesis instrumentation for the correction of æpondylolisthesis. .
: It is known that, substantially, spondylolisthesis is the forward displacement of~ a vertebra relative to its lower neighbour. In theory, any vertebra may~ be affected, but:the fi~th and the fourth lumbar vertebrae ar~ the most commonly concerned. ~ ~
Afecting more frequently women orlyoung girls than men, spondylolisthesis is usually olassified into five type~:
dysplastic, isthmian, traumatic, degenerative and :, .l pathological.
: Its degree of seriousness is measured by ~the distance travelled through:by the displaced vertebra with respect to its lower neighbour.
:There are four:stages:
~ The first stage is a; displaoement ~of a quarter of the~
¦ 20 antero-posterior diameter o~ the vertebral body.
j , . ' . ; ~
I The fourth stage corresponds to a complete displacement~of ~ :
the vertebral~body.
The s~econd and third stages~are the~intermediate stages.~
::He~etofore,: ~:although~ there~:~ are : certain surgical 25~: technlques for ~the trea~ment of spondylol;lsthesis, either by t:he~direct~tracti~on~on ~the ~slipped~ vertebra, or by the screwing of:the :pedi~cl~es of~thls sllpped~ vertebra, the~
i~ WO94~ 28 ;.;` .`. PCT/US93/10966 `~ 21~932~ f I reduction of the spondylolisthesis is not always ¦ satisfactory, :above all in t11e cases of serious spondylolisthesis.
. Surgery i5 in~eed indicated for those who have a l.ong past o~ lumbalg1a or sciatica, 1n the case of ev1dence of a verte~ral canal stenosis, a compression of the cauda equina : or a subjacent motor lesion, or those whose :~ spondylolisthesis rapidly evolves toward stage 3 or stage 4.
Generally, in surgery, an anterior or posterior 10 vertebral fusion, laminectomy with decompression of the pos~terior structures and an excisLon of the hypertrophied mass of the fibrous tissue~in the region.of the lysis may be indicated.
In isthmia~ spondylolisthesis, the bilateral isthmian 15 lyses are liable to be associated with a considerable : pseudoarthrosis ln relation with an emerging nerve root.
The discal state in the region of the spondylolisthesis sometimes requires a ~radicùlographic or discographic assessment. In vertebral canal stenoses, the decompression 20 without fusion may be a surgical-operation.
In actual fact, an effect1ve orthopedic surgery consists in returning the vertebra not only onto the axis of the : ~ spine~but also~to a position whioh is as correct as possibIe , ~
; relative to the ne1ghbouring:vertebrae. Over a period of . .
:~ ; 25 ~ time, or in thé course of lts;displacement/ this vertebra in r.
fact might~have been~subjected to lateral thrusts which have : caused it to pivot horiæonta1l:y to:~a more or less large 'r ~ ~ W094/10928 214932Z
extent so that a correct repositioning of the vertebra of course implies its rearward return but also a derotation.
~ttempts have already been made to correct ~j spondylolisthesis, for example by means of devices consisting of two pedicular scrèvs interconneGted by a transverse plate which, by screwing a nut bearing against the plate, act solely by translatlon of the concerned vertebra for putting it into alignment with the neighbouring vertebrae.
Thus, the device disclosed in French patent 2 615 095 (87 06 864) employs two rods which are longitudinally fixed in the vertebral column with the aid of pedicular screws and each serve as support means ~or~two screws ha~ing a double screw thread connected to the vertebra to be corrected.
These two double thread screws are~transversely connected by a rigid pIate constituting a bipedicular base. It is this : :
transverse plate which permits~acting on the vertebra to be corrected owing to~the;provision of a median opening for : :
receiving traction`forceps.
In fact, such a device does not permit acting in a sufficiently satisfactory manner, and experience has shown that a traction~on the medlan part of the plate has for effect to rearwa~rdly return the~ve~rtebra to be corrected too rapidly. Further, if this~vertebra must be derotated, ~it 25~ has been found that~ the~presence of the plate is lia~le to prevent the required~derotatlon~actlon owing tc the fact that th~ls~ induces at~ ~he~same~tlme~a certain return of the WO94/1~928 '`;'.,~ PCT/US93/10966 ~ ~2 214;~3~, ~ertebra.
` I
Now, surgical èxper1ence~ has~ revealed that it is :
desirable to act slowly on the vertebra by ~acting on each one of the double thread screws:independentl~y, so that the surgeon can gradually adjust for~each particular case his vertebra~derotation and/or return action.
~ Moreover, such'a device is:relatlvely complex and costly J. ` ~ ~ owing to: the number~of its co`mponent ~parts whlch ~further increases the: m~oanting difficulties encountered, by the surgeon duxing the surgical ~ operation. As concerns~ in particular the double:thread screw~ in~additlon to the ~fact that~it is long~and~costly~to prodace,:its impLantatlon: in:
the~pedlcles is~no~;~at all:Gonvenlent~
!~ Further~ this ~double::thread screw~:is: subjected to :' ~ 5:~ e~:t:remely~high~shear s~tresses~,~ma~inly in the:region::of ~ the '.~ junct~ion~with the~ nstrùmentation:appl~iances:or in the upper pa~t: ~of the screw~thread . ; ~
An:object:of :: thè~ ~invention~.: is: to~ provide a~ lumbar ~ ~:
osteosynthesis~ instrumentatlon~ for~: the~: correctlon~: of~
: 20~ spondylolisthesis, which,permits both retarning~the vertebra :~
:~ to the rear ~and pivoting it in the desired~ direction of `,;;`;~ rotatlon. ~Another object~of:the~lnvention~,is:~to~prov~lde~a~
~ double~thread ~ped`,ioular~ screw::~so;arranged~:as~to overcome~the~
; ~ aeorementloned drawbaoks~wh~le~ ~permi~etLng~;~mass,~ pr d UGtion~
`.~ '` 2S`'~ ic ~ls~ h pe than~ln~the , ~e~of screws know in~;the~art which~can~:o;nly`be prodaced~on~a ~sm ll~scale.;~
The:~:osteo nthes~1s :~:~ins~tramen ation~ according~ :~to~the :~:
WO94/1092X 2 1 ~ 9 3 2;2` PCT~US93/10966 "
invention comprises, for each lumbar vertebra, two pedicular .:double thread screws, one thread:of which`corresponds to the region of penetration of.the screw in the pe~lcle, two rods having surface asperities respectively associated wlth a 5 pedicular screw:and connected to: the latter by connection elements provided wi~th elements~for clamplng the rods.
According to the invention, each connection element is : - in:one piece and the sc~ew thread ~corresponding. to the :
region of penetration of;~the screw in the pedicle terminates 10 on an annular shoulder on which the; connection element be,~rs.
~:The~ derotatlon~ action exerted by means: of : this :instrumentation has the advantage:that it can be carried vut: ~:
slowly and with ~a~ certain amount: of control. over ~the 15 ~ movements, thereby,~affording ~on the whole in the two movements an excellent:preclsion in the~repositioning of the~
vertebra relative~:to its~neighbouring vertebrae.
` Further, the;arrangement~ of~a transverse~;~shoulder~:into ~ whioh tangential~l;y~fades~the screw~:thread~of~the part~of the:~
`~: 20 screw serving :to:~ penetrate : the pedicle, provides :a~
~: reinforcement ,or strengthening res:isting the;shear~ stresses :in this~region.~ The~continuous~`~per~ipher-L shoulder may:~als:o a~ct~as `a support~ for an~added:part~
According to~a~pa~ticular~ eature:of the invention,~: the~
:2s~ ::end~of ~the~screw~ thread~outsl~e~ the ~part~of the~ screw;~ r serving;to;~penètrate;the pedlcle~ lS ~extended~ by~ a~ ~screw~
thread;ed rod~:ada~ted~to~co~perate wLth an ancillary~screwi~ng ~ W094/10928 214932-2 PCT/U593/10966 ~ , . , ' - 6 - ' device. ~ ' ~. .
`1l The instrumentatlon according to the invention comprise~s an ancillary device for~screwing the pedicular double thread screw, this device bearing against the~screw threaded extension of said screw~.~ This ancillary device compris~es~ a ~' rod provided with; an end grip and includes~ a tubular end ,1 ' paxt which is arra~ged to pe~rmit the insertion of the - operating part~o~f the double thread~ screw, has a conical;~
free en~ part remote from the~grlp~tapering~toward the grip 0~ ;and is provided wi~th at Least one longitudlnal slot. This ancillary~device~further comprises a~tube freely sIidable on ' the rod for~the purpose~ of ~surrounding ~and~ gripping the ` ~ conical end part~of its~ tubular~end part~for~the purpose o~
,, '~ clamping;it on the operating part of the;pedicular;screw.
~ 15 ~ ~ With thLs ancillary devlce,~ the length of the operatlng `~ screw thread is ~almost~complete~ly enclosed ln the~ tubular~
end~part and clamped~owing~to the action of~ the second ~tube~
when~ ;the latter ;'surrounds the,~ conical~ en~ paxt of the;~ ~, , ,`~ tubular end~part'.~' After~having~provided~a prior bore in~the~
~ ~o pedicIe, the surgeon can ~in this~way easily screw the~double , ~
,~ thread~screw in'position.
`;-~ Furthé,r~featuresi`and~advantages~of the invention will be~
apparent~from;the`~'fol~lowl~ng description~ with re~erence~;to~
t~e~accompany'ing~'d~xawings;~which~illustrate~ two embodiments of~;the~inYention~by~way~of~ no~n-limitative examples.
In~the~draw'ng~s~
Fig. ~ s; ~ perspeC~t~ve ~vie- from abo~e of ~one~
214932~
` WO94/10928 ~ PCT/US93/10966 ¦` embodiment of the lumbar osteosynthesis instrumentation I according to the invention, mounted on the first lumbar ¦ vertebra and on the sacrum~
Fig. 2 is a partial perspective view of the instrumentation~shown in Fig. 1.
: :
Fig~ 3 is an elevational view in the transverse direction, partly in section, of the instrumentation shown , ` - in Fi`gs~ 1 and 2.
Fig. 4 is an elevational view to a larger scale of a pedicular double thread screw whlch is part of the : instrumentation shown in Figs. 1 to 3.
. Fig. 5 is a perspective view of :an embodiment of the ~: ~ ancillary device for mounting the pedl;cular screw shown in ~ Fig. 4.
;~ 15 ~ Fig~ 6 is a perspective vlew to.a larger scale of an al~ernative embodiment cf the connaction element between the ~ ~ osteosynthesis rod and the screw.
;~ Fig. 7 is a sectional view~taken on llne 7-7 o~ Fig. 6.
The lumbar osteosynthesis instrumentation show~ in:Figs.
1 to 3 is adapted to correct spondylollsthesis by the posterior approach:. : ~ ~
It compris;es, for each lumbar~ver:tebra to be corrected, : for example the ver~ebra L5 r two padicular screws 1 having two screw threads, two:;cylindrical rods 2, preferably two
`' W~ 94/1~28 2 1 4 9 ~ 2 2 ~cr/US93/10966 ~.. . ..
.
PEDlCULAR SCREW AND POSTERIOR SPINAL INSTRUMENTATION
. , `' The invention relates to lumbar osteosynthesis instrumentation for the correction of æpondylolisthesis. .
: It is known that, substantially, spondylolisthesis is the forward displacement of~ a vertebra relative to its lower neighbour. In theory, any vertebra may~ be affected, but:the fi~th and the fourth lumbar vertebrae ar~ the most commonly concerned. ~ ~
Afecting more frequently women orlyoung girls than men, spondylolisthesis is usually olassified into five type~:
dysplastic, isthmian, traumatic, degenerative and :, .l pathological.
: Its degree of seriousness is measured by ~the distance travelled through:by the displaced vertebra with respect to its lower neighbour.
:There are four:stages:
~ The first stage is a; displaoement ~of a quarter of the~
¦ 20 antero-posterior diameter o~ the vertebral body.
j , . ' . ; ~
I The fourth stage corresponds to a complete displacement~of ~ :
the vertebral~body.
The s~econd and third stages~are the~intermediate stages.~
::He~etofore,: ~:although~ there~:~ are : certain surgical 25~: technlques for ~the trea~ment of spondylol;lsthesis, either by t:he~direct~tracti~on~on ~the ~slipped~ vertebra, or by the screwing of:the :pedi~cl~es of~thls sllpped~ vertebra, the~
i~ WO94~ 28 ;.;` .`. PCT/US93/10966 `~ 21~932~ f I reduction of the spondylolisthesis is not always ¦ satisfactory, :above all in t11e cases of serious spondylolisthesis.
. Surgery i5 in~eed indicated for those who have a l.ong past o~ lumbalg1a or sciatica, 1n the case of ev1dence of a verte~ral canal stenosis, a compression of the cauda equina : or a subjacent motor lesion, or those whose :~ spondylolisthesis rapidly evolves toward stage 3 or stage 4.
Generally, in surgery, an anterior or posterior 10 vertebral fusion, laminectomy with decompression of the pos~terior structures and an excisLon of the hypertrophied mass of the fibrous tissue~in the region.of the lysis may be indicated.
In isthmia~ spondylolisthesis, the bilateral isthmian 15 lyses are liable to be associated with a considerable : pseudoarthrosis ln relation with an emerging nerve root.
The discal state in the region of the spondylolisthesis sometimes requires a ~radicùlographic or discographic assessment. In vertebral canal stenoses, the decompression 20 without fusion may be a surgical-operation.
In actual fact, an effect1ve orthopedic surgery consists in returning the vertebra not only onto the axis of the : ~ spine~but also~to a position whioh is as correct as possibIe , ~
; relative to the ne1ghbouring:vertebrae. Over a period of . .
:~ ; 25 ~ time, or in thé course of lts;displacement/ this vertebra in r.
fact might~have been~subjected to lateral thrusts which have : caused it to pivot horiæonta1l:y to:~a more or less large 'r ~ ~ W094/10928 214932Z
extent so that a correct repositioning of the vertebra of course implies its rearward return but also a derotation.
~ttempts have already been made to correct ~j spondylolisthesis, for example by means of devices consisting of two pedicular scrèvs interconneGted by a transverse plate which, by screwing a nut bearing against the plate, act solely by translatlon of the concerned vertebra for putting it into alignment with the neighbouring vertebrae.
Thus, the device disclosed in French patent 2 615 095 (87 06 864) employs two rods which are longitudinally fixed in the vertebral column with the aid of pedicular screws and each serve as support means ~or~two screws ha~ing a double screw thread connected to the vertebra to be corrected.
These two double thread screws are~transversely connected by a rigid pIate constituting a bipedicular base. It is this : :
transverse plate which permits~acting on the vertebra to be corrected owing to~the;provision of a median opening for : :
receiving traction`forceps.
In fact, such a device does not permit acting in a sufficiently satisfactory manner, and experience has shown that a traction~on the medlan part of the plate has for effect to rearwa~rdly return the~ve~rtebra to be corrected too rapidly. Further, if this~vertebra must be derotated, ~it 25~ has been found that~ the~presence of the plate is lia~le to prevent the required~derotatlon~actlon owing tc the fact that th~ls~ induces at~ ~he~same~tlme~a certain return of the WO94/1~928 '`;'.,~ PCT/US93/10966 ~ ~2 214;~3~, ~ertebra.
` I
Now, surgical èxper1ence~ has~ revealed that it is :
desirable to act slowly on the vertebra by ~acting on each one of the double thread screws:independentl~y, so that the surgeon can gradually adjust for~each particular case his vertebra~derotation and/or return action.
~ Moreover, such'a device is:relatlvely complex and costly J. ` ~ ~ owing to: the number~of its co`mponent ~parts whlch ~further increases the: m~oanting difficulties encountered, by the surgeon duxing the surgical ~ operation. As concerns~ in particular the double:thread screw~ in~additlon to the ~fact that~it is long~and~costly~to prodace,:its impLantatlon: in:
the~pedlcles is~no~;~at all:Gonvenlent~
!~ Further~ this ~double::thread screw~:is: subjected to :' ~ 5:~ e~:t:remely~high~shear s~tresses~,~ma~inly in the:region::of ~ the '.~ junct~ion~with the~ nstrùmentation:appl~iances:or in the upper pa~t: ~of the screw~thread . ; ~
An:object:of :: thè~ ~invention~.: is: to~ provide a~ lumbar ~ ~:
osteosynthesis~ instrumentatlon~ for~: the~: correctlon~: of~
: 20~ spondylolisthesis, which,permits both retarning~the vertebra :~
:~ to the rear ~and pivoting it in the desired~ direction of `,;;`;~ rotatlon. ~Another object~of:the~lnvention~,is:~to~prov~lde~a~
~ double~thread ~ped`,ioular~ screw::~so;arranged~:as~to overcome~the~
; ~ aeorementloned drawbaoks~wh~le~ ~permi~etLng~;~mass,~ pr d UGtion~
`.~ '` 2S`'~ ic ~ls~ h pe than~ln~the , ~e~of screws know in~;the~art which~can~:o;nly`be prodaced~on~a ~sm ll~scale.;~
The:~:osteo nthes~1s :~:~ins~tramen ation~ according~ :~to~the :~:
WO94/1092X 2 1 ~ 9 3 2;2` PCT~US93/10966 "
invention comprises, for each lumbar vertebra, two pedicular .:double thread screws, one thread:of which`corresponds to the region of penetration of.the screw in the pe~lcle, two rods having surface asperities respectively associated wlth a 5 pedicular screw:and connected to: the latter by connection elements provided wi~th elements~for clamplng the rods.
According to the invention, each connection element is : - in:one piece and the sc~ew thread ~corresponding. to the :
region of penetration of;~the screw in the pedicle terminates 10 on an annular shoulder on which the; connection element be,~rs.
~:The~ derotatlon~ action exerted by means: of : this :instrumentation has the advantage:that it can be carried vut: ~:
slowly and with ~a~ certain amount: of control. over ~the 15 ~ movements, thereby,~affording ~on the whole in the two movements an excellent:preclsion in the~repositioning of the~
vertebra relative~:to its~neighbouring vertebrae.
` Further, the;arrangement~ of~a transverse~;~shoulder~:into ~ whioh tangential~l;y~fades~the screw~:thread~of~the part~of the:~
`~: 20 screw serving :to:~ penetrate : the pedicle, provides :a~
~: reinforcement ,or strengthening res:isting the;shear~ stresses :in this~region.~ The~continuous~`~per~ipher-L shoulder may:~als:o a~ct~as `a support~ for an~added:part~
According to~a~pa~ticular~ eature:of the invention,~: the~
:2s~ ::end~of ~the~screw~ thread~outsl~e~ the ~part~of the~ screw;~ r serving;to;~penètrate;the pedlcle~ lS ~extended~ by~ a~ ~screw~
thread;ed rod~:ada~ted~to~co~perate wLth an ancillary~screwi~ng ~ W094/10928 214932-2 PCT/U593/10966 ~ , . , ' - 6 - ' device. ~ ' ~. .
`1l The instrumentatlon according to the invention comprise~s an ancillary device for~screwing the pedicular double thread screw, this device bearing against the~screw threaded extension of said screw~.~ This ancillary device compris~es~ a ~' rod provided with; an end grip and includes~ a tubular end ,1 ' paxt which is arra~ged to pe~rmit the insertion of the - operating part~o~f the double thread~ screw, has a conical;~
free en~ part remote from the~grlp~tapering~toward the grip 0~ ;and is provided wi~th at Least one longitudlnal slot. This ancillary~device~further comprises a~tube freely sIidable on ' the rod for~the purpose~ of ~surrounding ~and~ gripping the ` ~ conical end part~of its~ tubular~end part~for~the purpose o~
,, '~ clamping;it on the operating part of the;pedicular;screw.
~ 15 ~ ~ With thLs ancillary devlce,~ the length of the operatlng `~ screw thread is ~almost~complete~ly enclosed ln the~ tubular~
end~part and clamped~owing~to the action of~ the second ~tube~
when~ ;the latter ;'surrounds the,~ conical~ en~ paxt of the;~ ~, , ,`~ tubular end~part'.~' After~having~provided~a prior bore in~the~
~ ~o pedicIe, the surgeon can ~in this~way easily screw the~double , ~
,~ thread~screw in'position.
`;-~ Furthé,r~featuresi`and~advantages~of the invention will be~
apparent~from;the`~'fol~lowl~ng description~ with re~erence~;to~
t~e~accompany'ing~'d~xawings;~which~illustrate~ two embodiments of~;the~inYention~by~way~of~ no~n-limitative examples.
In~the~draw'ng~s~
Fig. ~ s; ~ perspeC~t~ve ~vie- from abo~e of ~one~
214932~
` WO94/10928 ~ PCT/US93/10966 ¦` embodiment of the lumbar osteosynthesis instrumentation I according to the invention, mounted on the first lumbar ¦ vertebra and on the sacrum~
Fig. 2 is a partial perspective view of the instrumentation~shown in Fig. 1.
: :
Fig~ 3 is an elevational view in the transverse direction, partly in section, of the instrumentation shown , ` - in Fi`gs~ 1 and 2.
Fig. 4 is an elevational view to a larger scale of a pedicular double thread screw whlch is part of the : instrumentation shown in Figs. 1 to 3.
. Fig. 5 is a perspective view of :an embodiment of the ~: ~ ancillary device for mounting the pedl;cular screw shown in ~ Fig. 4.
;~ 15 ~ Fig~ 6 is a perspective vlew to.a larger scale of an al~ernative embodiment cf the connaction element between the ~ ~ osteosynthesis rod and the screw.
;~ Fig. 7 is a sectional view~taken on llne 7-7 o~ Fig. 6.
The lumbar osteosynthesis instrumentation show~ in:Figs.
1 to 3 is adapted to correct spondylollsthesis by the posterior approach:. : ~ ~
It compris;es, for each lumbar~ver:tebra to be corrected, : for example the ver~ebra L5 r two padicular screws 1 having two screw threads, two:;cylindrical rods 2, preferably two
2:5 ~:~rods~ o~ the~so-called~Cotrel~type~having surface asperities or:knurl~ing extending~ longi~tudinally along the concerned lumbar segment~ (vertebrae~ L5,~;~L4 and sacrum S in the i,"~: :: ~ :
WO~4/lQ928 PCT/US93/10966 21~9322 -`
assembly shown in Fig. 1), connection elem2nts 3 connecting each pedicular screw 1 to the adjacent~ rod 2, pedicular screws 4 for secùring the rods 2 to the vertebra L4 and to the sacrum S, and de:vices~ 5 providing a transverse :
connection between the rods. All these elements except the pedicular screws l~and the connection elements 3 are known and: there~fore need no speclal description.
- Each connection ~element 3: has, when viewed in thé
transverse dlrection, a substantially L-shaped profile consisting of an enlarged base 3a in whi~ch is provided a through passage 10 receiving the rod:2~and having an axis : X-X~ This portion 3a has on one slde a cylindrical surface :
. and on the other~side a planar surface and is extended by a : thin portion 3b. : The latter ha~ two parallel planar 1S~ surfaces and is~provided with~an op.enin~ 7 for the ~passage o:f the pedicular screw 1:. The~ opening 7 consists of: a : :~` cylindrlcal central :part having an axis Z-Z extended on each ~; : side~by two.conical parts 7b, 7c opening: ~onto the planar~ :
~: sux~aces. The :taper~of~ these conical parts is such that~::it permits an inclination of the axis of the screw ~1 rel:ative to the axis 2-Z of about + 15, the angular limits of this :;axis correspondlng to ~the axes~ Y-Y and Y'-Y' (Fig. 7):. A
: : tapped opening 6~tlansversely opens~onto the bore or passage 0 and~receives~al~screw 20 for radially cIamping the rod ~2.
: :25~ The :sur~ace 3c o~ the element~3:remote from the passage 10 : is;completely:planar.;
The~e:lement 3~:~constitutes~;the means:for securing the rod ~ WOg4/l0928 ~l~9~22 Pcr/uss3/lns66 L
g and the means for screwing the screw 1. The distance between the axes of the screw 1 and rod 2 vary with the ! subject so that the sur.geon can choose the most appropriate I element 3. : ~
Each screw 1 comprises from its point 8 a first screw threaded part 9 extending to the length of penetration of the screw 1 in the pedicular and a second screw threaded .
- part 11 which is outside the region of penetration ln the pedicle and is termed the "operating" part. On the side remote from the screw threaded paxt 9 the operating part 11 is extended by a profiled end portion 12, constituted ~for example by two flats 13 adapted~`to~permlt both the gripping of the double thread screw 1 and the screwing thereof by : :
means of an ancillary device 14 (F~. 5) which will :be described hereinafter.
~; At the end` remote from the pro~iled end portion 12, the screw threaded operating part 11 ~ is extended ~by a short ~:
:~ smooth region 15~ terminating in: a continuous peripheral s:houlder 16 constituting the~end of the screw threaded part 9. This shoulder 16 bears:against the planar suxface of thë
element.3 which is the most remote rom the screw threaded : part 11, consequent}y the~screw 1 cannot pass through the element 3.
. ` .
: :
The ~screw thread 18 of this:: screw thread~d part is. ~t : 25 adjacent the shoulder 16 and the ~epth of the thread 21 :c}ose to the shoulder 1:6 gradually~ diminishes until it tangentially:merges~wlth or~fades~ onto a cylindrical sector W094/l0928 ,;. "-, PCT/U~93/109~6 ~
2`i49322" , I
o ~
: , 22 bordered by the shoulder 16 ~which thus forms a screw reinforcing reglon in:this position. The sho.ulder 16 may ~act as~a support;for a devlce o~r~ an: associated connection element'3.
The operating part 11 of the screw 1 is constltuted by ,a metal screw thread of small pitch, for:example between 0.5 and 2~mm:and preferably~b,etween 0.8~and ~1 mm, adapted to , receive:a nut 23 for :clamping the ~connection èlement 3 against the sho'ulder 16.
: ~::: 1o This instrumentation has the folIowing advantages~
The fact that the connection element ~3 ~ lS made ln a single~ piece not ~:only makes this element cheaper to I : ~ manufacture but also. simplifies the positioning of the ::: element by the surgeon, and above:alr improves the strength i.
~ 5 of~he connection between the rod 2':: having~asperiities and~
.
the pedicular screw 1. :~
As previously explalned, the pedicular :double thread~
screw 1 is su~jected:to~h~igh~mechanical~stresses of:multiple~ I
origins;: it must~resist these; various~ tresses for a . : :
relatively long! perlod of tlme the duration of whlch depends on each~patlent.~ The~screw 1 must~therefore be~as simple~as possib~le to~moun~t~during the ~surgica~ ope:rations, but must: ;~
. also have sufficient~strength~to wlths~ta~nd ~ all the force:s ~ 1.
during~and~after~the~operatl.on.:~ Now,~.wi;th~ the pedicular :2~5~; screws~employed:,heretofo~e,~it::has~:been~found that fractures generally~ occur in the region~between the two screw threads. :
The~'inventlon~remedles~thls~ ~slt;uatLon~iby terminating the Zl ~
WO94/10928 PfCT/US93/10966 f 21 ~`9 322 i . . .
screw tllread 18 for anchoring in the pedicle in the substantially~tàngential region 22. Consequently, the screw thread 18 does not "open ;out" onto the shoulder 16 for supporting the connection element 3 and consequently ensures 5 that this shoulder 1~6 has ~a peripheral ~continuity and a sufficient supporting thickness. This~supporting thickness thus affords the`maximum mechanical~resistance to the forces ~- - trànsmitted to the connection element~ 3 and therefore exerted by the latter.
Another advantage afforded by thls arrangement of ~the anchoring screw thread`18 resides in the~fact that, when it is desired to e~ffeff~t a bicortical anchorage~by reaching the opposi~te cortical part~of the vertebra~and~with the screw~
thread length corresponding to the ~iength of the~ passage through the vertebfra,~the surgeon is~informed of the desired : . ~
~ ~ ` final position of the¦screw thread.~ ~The stoppage of the ,i latter in its~upper;part indeed ~constitutes a warning in ; that the surgeon must suddenly;exert a higher` torque. He , ~ ~
2 ~ust~therefore stop~his sff-rewing effort.
~ 20 Owing to the~provision of the proflled end portion 12t ¦;~ the engagement of the pedicular sf~rew 1 by ~he ancillary devLce~14 no longer;occurs in~ the o~ntral region of the f~ screw, as desf~ribed in~said patfent 2 615 095, but at the ree~end~ of the~sarew.~This end~region~may be i~ ~the form ~ 2s ~Of two~ flats 1~3~ provlded~ on a smooth,~ or optionally screw f" ~ threa~ded,~end part~to~permit the ancillary device 14 to act on~the; screw. ~
W094/10928 2 ~ ~`9 3 ~ 2 ~ PCT/US93/10966 ~.
,',;~ .
.
- 12 - ~ ' This ancillary device comprlses a rod 24 provided with a tubular end part 25 and, at its opposite end, a manual grip 26. The tubular 'part 25~is s~o dLmensioned as to permit the lnsertion therein of the operating part 11 of the screw 1, and'the ancillary device 14 is completed by a~tu~e or sleeve 27 coaxial with the~rod 24 and slldabl~y ~mounted on' the latter so as to be capable of.surrounding ~the tubular: part Z5. at the end of its travel.
The tubular part 25 is provided with longitudinal slots 28 startlng at its free end, for.~ example~:~three slots as illustrated, extending a~long a part of~ the len'gth: of~ the ;,, . ~ . , region 25. The free end:portion 29 of:the latter is~conical : and~tapers in the dire~tlon toward the grip:Z6. Beyond~ the Blots: 28, at a certain:distance ~rom ~he ~latter, there is provided a hollow pxofile matching the~profiled end portion 12~of~ the`screw,~:~or example, as shown in Fig. 5,:two flats 31 whose longitudinal surfaces are parallel~:. The two~ flats 31~are adapte'd to;receive corresponding flats 13 of the ~ screw 1:and thus lock~.the:latter against rotation after~ the '~ 20 insertion of'the operating part 11 in the t:ubular part 25 In the dlrectlon toward the canical end~part 29, the~ f~lats;~
'.~ 31~are~extended:~by~longitudinal;recesses~:32 for receiving '~
the~opera~ting~part 1~ of;~the screw 1~ hastly, in ~order~:to~
~ permit a visual~checking of the~posit:ion~of~the profiled~end: : ~ ~
;~ 25 ~;portion 1~2~ on~the:~flats~3i, the~tubul~ar~p~art~25~is provided ~;
`~ : with~a transverse~opéning 33~'in~the:region of~.the flats.
When the~ operatlng ~part 11~ s:inse;rted:in the tubular 4~ wog4/lo9~8 2149322 PCT/US93/l0966 :
:
part 25 with its end portion 12 locked against rotation between the flats~31, the surgeon slide~s~the~tube 27 along , .
the tubular part 25 until tlie conical end portion 29 is made to grip round the operating part 11, the tapered poxtion 29 .
5 thus constitutlng a holding chuck~for the~ screw 1. The two '~
~flats constitute additional~ means for preventing a reverse rotation of the pedicùlar screw~1 in the anc~illary device ~ 14.` The ancillary device~;14 also serves ~to~screw the nut 23 r ~ clamping the screw 1~in~the connection element 3. It is 10 provided in its end 29 with ~a corresponding recess for :
enyaging this nut 23.
The instrumentation just described is used in the ,:
~ following manner.
, :
Before placing in~position the su~port~rods 2, which are 15 for example the known Cotrel rods (Reglstered Trademark), the surgeon suitabl-~ anc~hors with his anclllary device 14 the double thread~screws~l~in each of the~ pedicles~ of the~
vertebra L5 to CorreGt. ~Then he secures the support rods 2 to the neighbour~ing vertebrae, or, as in the embodiment shown in Fig. 1, to the sacrum S and vertebra L4. Then he : ! ,` , ` , : ~ : , firmly fixes the connection elements 3 to the rods 2 by means~of a radlal~clamping s~crew 20 (Flg. 1~.
At t~his stage~,`the two~transv~erse connection rods 5 are ;~
not yet;instaLled. In~order~to correct the vertebra L5, ~ r `
25~ i.e. to return~ lt ~rearward~ly ~ (spondylolisthesis) and/or derotate lt, the~sury~eon~acts~on the nuts 23 clamping the con~nec~tlon elemen s 3~by~neans~Df an~aDcillary device and W094/10928 ~ - PCT/US93/10966 . .
- 14 _ preferably two ancillary devices, each being disposed on one i of the nuts 23 o~ the two screws 1. r~e is now free to act, ~ as desired, more on the screwiny of one of the nuts 23 than `I , .
on the screwing of the other, depending on the movement he wishes to impart to the vertebra LSI as he iS free to act in an identical manner on the two nuts 23. ~
Each time the surgeon acts on one:of the nuts 23, he ~ exerts by the bearing of the screw thread-nut system on the ; connection ele~ent 3 firmly connected to the support rod 2, ;i 10 a traction on the vertebra L5 in a direction toward the it ~: connection element 3. When he acts on a slngle one of the
WO~4/lQ928 PCT/US93/10966 21~9322 -`
assembly shown in Fig. 1), connection elem2nts 3 connecting each pedicular screw 1 to the adjacent~ rod 2, pedicular screws 4 for secùring the rods 2 to the vertebra L4 and to the sacrum S, and de:vices~ 5 providing a transverse :
connection between the rods. All these elements except the pedicular screws l~and the connection elements 3 are known and: there~fore need no speclal description.
- Each connection ~element 3: has, when viewed in thé
transverse dlrection, a substantially L-shaped profile consisting of an enlarged base 3a in whi~ch is provided a through passage 10 receiving the rod:2~and having an axis : X-X~ This portion 3a has on one slde a cylindrical surface :
. and on the other~side a planar surface and is extended by a : thin portion 3b. : The latter ha~ two parallel planar 1S~ surfaces and is~provided with~an op.enin~ 7 for the ~passage o:f the pedicular screw 1:. The~ opening 7 consists of: a : :~` cylindrlcal central :part having an axis Z-Z extended on each ~; : side~by two.conical parts 7b, 7c opening: ~onto the planar~ :
~: sux~aces. The :taper~of~ these conical parts is such that~::it permits an inclination of the axis of the screw ~1 rel:ative to the axis 2-Z of about + 15, the angular limits of this :;axis correspondlng to ~the axes~ Y-Y and Y'-Y' (Fig. 7):. A
: : tapped opening 6~tlansversely opens~onto the bore or passage 0 and~receives~al~screw 20 for radially cIamping the rod ~2.
: :25~ The :sur~ace 3c o~ the element~3:remote from the passage 10 : is;completely:planar.;
The~e:lement 3~:~constitutes~;the means:for securing the rod ~ WOg4/l0928 ~l~9~22 Pcr/uss3/lns66 L
g and the means for screwing the screw 1. The distance between the axes of the screw 1 and rod 2 vary with the ! subject so that the sur.geon can choose the most appropriate I element 3. : ~
Each screw 1 comprises from its point 8 a first screw threaded part 9 extending to the length of penetration of the screw 1 in the pedicular and a second screw threaded .
- part 11 which is outside the region of penetration ln the pedicle and is termed the "operating" part. On the side remote from the screw threaded paxt 9 the operating part 11 is extended by a profiled end portion 12, constituted ~for example by two flats 13 adapted~`to~permlt both the gripping of the double thread screw 1 and the screwing thereof by : :
means of an ancillary device 14 (F~. 5) which will :be described hereinafter.
~; At the end` remote from the pro~iled end portion 12, the screw threaded operating part 11 ~ is extended ~by a short ~:
:~ smooth region 15~ terminating in: a continuous peripheral s:houlder 16 constituting the~end of the screw threaded part 9. This shoulder 16 bears:against the planar suxface of thë
element.3 which is the most remote rom the screw threaded : part 11, consequent}y the~screw 1 cannot pass through the element 3.
. ` .
: :
The ~screw thread 18 of this:: screw thread~d part is. ~t : 25 adjacent the shoulder 16 and the ~epth of the thread 21 :c}ose to the shoulder 1:6 gradually~ diminishes until it tangentially:merges~wlth or~fades~ onto a cylindrical sector W094/l0928 ,;. "-, PCT/U~93/109~6 ~
2`i49322" , I
o ~
: , 22 bordered by the shoulder 16 ~which thus forms a screw reinforcing reglon in:this position. The sho.ulder 16 may ~act as~a support;for a devlce o~r~ an: associated connection element'3.
The operating part 11 of the screw 1 is constltuted by ,a metal screw thread of small pitch, for:example between 0.5 and 2~mm:and preferably~b,etween 0.8~and ~1 mm, adapted to , receive:a nut 23 for :clamping the ~connection èlement 3 against the sho'ulder 16.
: ~::: 1o This instrumentation has the folIowing advantages~
The fact that the connection element ~3 ~ lS made ln a single~ piece not ~:only makes this element cheaper to I : ~ manufacture but also. simplifies the positioning of the ::: element by the surgeon, and above:alr improves the strength i.
~ 5 of~he connection between the rod 2':: having~asperiities and~
.
the pedicular screw 1. :~
As previously explalned, the pedicular :double thread~
screw 1 is su~jected:to~h~igh~mechanical~stresses of:multiple~ I
origins;: it must~resist these; various~ tresses for a . : :
relatively long! perlod of tlme the duration of whlch depends on each~patlent.~ The~screw 1 must~therefore be~as simple~as possib~le to~moun~t~during the ~surgica~ ope:rations, but must: ;~
. also have sufficient~strength~to wlths~ta~nd ~ all the force:s ~ 1.
during~and~after~the~operatl.on.:~ Now,~.wi;th~ the pedicular :2~5~; screws~employed:,heretofo~e,~it::has~:been~found that fractures generally~ occur in the region~between the two screw threads. :
The~'inventlon~remedles~thls~ ~slt;uatLon~iby terminating the Zl ~
WO94/10928 PfCT/US93/10966 f 21 ~`9 322 i . . .
screw tllread 18 for anchoring in the pedicle in the substantially~tàngential region 22. Consequently, the screw thread 18 does not "open ;out" onto the shoulder 16 for supporting the connection element 3 and consequently ensures 5 that this shoulder 1~6 has ~a peripheral ~continuity and a sufficient supporting thickness. This~supporting thickness thus affords the`maximum mechanical~resistance to the forces ~- - trànsmitted to the connection element~ 3 and therefore exerted by the latter.
Another advantage afforded by thls arrangement of ~the anchoring screw thread`18 resides in the~fact that, when it is desired to e~ffeff~t a bicortical anchorage~by reaching the opposi~te cortical part~of the vertebra~and~with the screw~
thread length corresponding to the ~iength of the~ passage through the vertebfra,~the surgeon is~informed of the desired : . ~
~ ~ ` final position of the¦screw thread.~ ~The stoppage of the ,i latter in its~upper;part indeed ~constitutes a warning in ; that the surgeon must suddenly;exert a higher` torque. He , ~ ~
2 ~ust~therefore stop~his sff-rewing effort.
~ 20 Owing to the~provision of the proflled end portion 12t ¦;~ the engagement of the pedicular sf~rew 1 by ~he ancillary devLce~14 no longer;occurs in~ the o~ntral region of the f~ screw, as desf~ribed in~said patfent 2 615 095, but at the ree~end~ of the~sarew.~This end~region~may be i~ ~the form ~ 2s ~Of two~ flats 1~3~ provlded~ on a smooth,~ or optionally screw f" ~ threa~ded,~end part~to~permit the ancillary device 14 to act on~the; screw. ~
W094/10928 2 ~ ~`9 3 ~ 2 ~ PCT/US93/10966 ~.
,',;~ .
.
- 12 - ~ ' This ancillary device comprlses a rod 24 provided with a tubular end part 25 and, at its opposite end, a manual grip 26. The tubular 'part 25~is s~o dLmensioned as to permit the lnsertion therein of the operating part 11 of the screw 1, and'the ancillary device 14 is completed by a~tu~e or sleeve 27 coaxial with the~rod 24 and slldabl~y ~mounted on' the latter so as to be capable of.surrounding ~the tubular: part Z5. at the end of its travel.
The tubular part 25 is provided with longitudinal slots 28 startlng at its free end, for.~ example~:~three slots as illustrated, extending a~long a part of~ the len'gth: of~ the ;,, . ~ . , region 25. The free end:portion 29 of:the latter is~conical : and~tapers in the dire~tlon toward the grip:Z6. Beyond~ the Blots: 28, at a certain:distance ~rom ~he ~latter, there is provided a hollow pxofile matching the~profiled end portion 12~of~ the`screw,~:~or example, as shown in Fig. 5,:two flats 31 whose longitudinal surfaces are parallel~:. The two~ flats 31~are adapte'd to;receive corresponding flats 13 of the ~ screw 1:and thus lock~.the:latter against rotation after~ the '~ 20 insertion of'the operating part 11 in the t:ubular part 25 In the dlrectlon toward the canical end~part 29, the~ f~lats;~
'.~ 31~are~extended:~by~longitudinal;recesses~:32 for receiving '~
the~opera~ting~part 1~ of;~the screw 1~ hastly, in ~order~:to~
~ permit a visual~checking of the~posit:ion~of~the profiled~end: : ~ ~
;~ 25 ~;portion 1~2~ on~the:~flats~3i, the~tubul~ar~p~art~25~is provided ~;
`~ : with~a transverse~opéning 33~'in~the:region of~.the flats.
When the~ operatlng ~part 11~ s:inse;rted:in the tubular 4~ wog4/lo9~8 2149322 PCT/US93/l0966 :
:
part 25 with its end portion 12 locked against rotation between the flats~31, the surgeon slide~s~the~tube 27 along , .
the tubular part 25 until tlie conical end portion 29 is made to grip round the operating part 11, the tapered poxtion 29 .
5 thus constitutlng a holding chuck~for the~ screw 1. The two '~
~flats constitute additional~ means for preventing a reverse rotation of the pedicùlar screw~1 in the anc~illary device ~ 14.` The ancillary device~;14 also serves ~to~screw the nut 23 r ~ clamping the screw 1~in~the connection element 3. It is 10 provided in its end 29 with ~a corresponding recess for :
enyaging this nut 23.
The instrumentation just described is used in the ,:
~ following manner.
, :
Before placing in~position the su~port~rods 2, which are 15 for example the known Cotrel rods (Reglstered Trademark), the surgeon suitabl-~ anc~hors with his anclllary device 14 the double thread~screws~l~in each of the~ pedicles~ of the~
vertebra L5 to CorreGt. ~Then he secures the support rods 2 to the neighbour~ing vertebrae, or, as in the embodiment shown in Fig. 1, to the sacrum S and vertebra L4. Then he : ! ,` , ` , : ~ : , firmly fixes the connection elements 3 to the rods 2 by means~of a radlal~clamping s~crew 20 (Flg. 1~.
At t~his stage~,`the two~transv~erse connection rods 5 are ;~
not yet;instaLled. In~order~to correct the vertebra L5, ~ r `
25~ i.e. to return~ lt ~rearward~ly ~ (spondylolisthesis) and/or derotate lt, the~sury~eon~acts~on the nuts 23 clamping the con~nec~tlon elemen s 3~by~neans~Df an~aDcillary device and W094/10928 ~ - PCT/US93/10966 . .
- 14 _ preferably two ancillary devices, each being disposed on one i of the nuts 23 o~ the two screws 1. r~e is now free to act, ~ as desired, more on the screwiny of one of the nuts 23 than `I , .
on the screwing of the other, depending on the movement he wishes to impart to the vertebra LSI as he iS free to act in an identical manner on the two nuts 23. ~
Each time the surgeon acts on one:of the nuts 23, he ~ exerts by the bearing of the screw thread-nut system on the ; connection ele~ent 3 firmly connected to the support rod 2, ;i 10 a traction on the vertebra L5 in a direction toward the it ~: connection element 3. When he acts on a slngle one of the
3: ~uts 23~ he also produces a slight rotation of the vertebra ~: L5 about itself. When ~e acts equally on both nuts 23, he! . ~
produces a rearward return of the ver~ebra L5.
15In all cases, the flne pitch ~of the screw thread 11 3l supporting the correction nut 23: permits acting very . progressively on the vertebra. When.the:verte~ra is finally in the position required by the surgeon~ the latter ~severs : the double thread screw 1 above the nut 23. The:severing of l ~20 the rod deforms the screw thread 11 and this subsequently ¦~ prevents the unscrewing of the nut 23.
It lS only at this moment ~hat~ the transverse rods :5 interconnecting the rods 2 can~be mounted, thereby~achievi~g a rectangulation of the whole flnal instrumentation.
~ The~instrumentation according to the~invention is easier to place ln positlon by the surgeon than that: dlsclosed~ in~
said~French patent ;2; 6;15: 095, ;~cheaper as concerns the :
~' WO94/10~2~ 2 1 4 9 3 2 2 PCT/US93/10966 `
fabrication of the screw, and more reliable in use; it no lon~er re~uires a transverse handling plate in the re~ion of the connection elements 3. The screwing of the pedicular screws 1 by their profiled end portions 12 rather than by their central regions~ as in the aforementioned prior instrumentationl is also more convenient for the surgeon.
It must be u~derstood that the scope of the invention is not intended to be Iimited to the described embodiments and various modifications may be made. For example, it is obvious that the end portion 12 may have any suitable profile other than that described, ~he same being true of the corresponding two flats 31 of the ancillary device 14.
Likewise, in the alternative embodiment shown in Fig. 6, the connection element 3.may be con~tructed to have, as viewed in the transverse direction, a substantlally L-shaped profile and be disposed in such manner that its plana~
surace 3c (in contact ~with the nut 23 in Fig. 3) is inverted, by turning the element round, so as to be closer to the adjacent vertebra. :
,.
:
produces a rearward return of the ver~ebra L5.
15In all cases, the flne pitch ~of the screw thread 11 3l supporting the correction nut 23: permits acting very . progressively on the vertebra. When.the:verte~ra is finally in the position required by the surgeon~ the latter ~severs : the double thread screw 1 above the nut 23. The:severing of l ~20 the rod deforms the screw thread 11 and this subsequently ¦~ prevents the unscrewing of the nut 23.
It lS only at this moment ~hat~ the transverse rods :5 interconnecting the rods 2 can~be mounted, thereby~achievi~g a rectangulation of the whole flnal instrumentation.
~ The~instrumentation according to the~invention is easier to place ln positlon by the surgeon than that: dlsclosed~ in~
said~French patent ;2; 6;15: 095, ;~cheaper as concerns the :
~' WO94/10~2~ 2 1 4 9 3 2 2 PCT/US93/10966 `
fabrication of the screw, and more reliable in use; it no lon~er re~uires a transverse handling plate in the re~ion of the connection elements 3. The screwing of the pedicular screws 1 by their profiled end portions 12 rather than by their central regions~ as in the aforementioned prior instrumentationl is also more convenient for the surgeon.
It must be u~derstood that the scope of the invention is not intended to be Iimited to the described embodiments and various modifications may be made. For example, it is obvious that the end portion 12 may have any suitable profile other than that described, ~he same being true of the corresponding two flats 31 of the ancillary device 14.
Likewise, in the alternative embodiment shown in Fig. 6, the connection element 3.may be con~tructed to have, as viewed in the transverse direction, a substantlally L-shaped profile and be disposed in such manner that its plana~
surace 3c (in contact ~with the nut 23 in Fig. 3) is inverted, by turning the element round, so as to be closer to the adjacent vertebra. :
,.
:
Claims (15)
1. Lumbar osteosynthesis instrumentation for the correction of spondylolisthesis by a posterior approach, comprising in combination for each lumbar vertebra, two pedicular screws each having a first screw thread and a second screw thread, said first screw thread corresponding to a region of penetration of said pedicular screw in the pedicle of the vertebra, two cylindrical rods each associated with a respective pedicular screw, connection elements each interconnecting each rod and the associated pedicular screw, an annular bearing shoulder for the connection element interposed between said first and second srew threads on each pedicular screw, clamping elements each associated with a respective connecting element for clamping the respective rod, said first screw thread of each pedicular screw terminating on said shoulder and said shoulder being separated by a smooth part from said second screw thread outside said region of penetration of said first screw thread in said pedicle.
2. Instrumentation according to claim 1, wherein each connection element has a substantially L-shaped profile and a planar surface and is disposed, when the instrumentation is placed in position, in such manner that said planar surface is placed as close as possible to the adjacent vertebra.
3. Instrumentation according to claim 1, wherein each connection element has a substantially L-shaped profile and a planar surface and is disposed, when the instrumentation is placed in position, in such manner that said planar surface is spaced away from the adjacent vertebra.
4. Instrumentation according to claim 1, wherein each connection element has two opposed planar surfaces and is provided with an opening for receiving the respective pedicular screw, said opening having a cylindrical central part extended at both ends by conical parts each opening out onto a respective one of said planar surfaces of said connection element.
5. Instrumentation according to claim 1, comprising a profiled end portion at an end of said second screw thread remote from said shoulder of each pedicular screw for cooperation with an ancillary screwing device.
6. Instrumentation according to claim 1, wherein each second screw thread has a pitch of substantially 0.5 to 2 mm.
7. Instrumentation according to claim 1, wherein each second screw thread has a pitch of 0.8 to 1 mm
8. Instrumentation according to claim 5 in combination with an ancillary device for screwing each pedicular screw by a part thereof, termed operating part, outside said region of penetration of said pedicular screw in said pedicle, said ancillary device comprising a rod provided with an end grip and a tubular end part which is arranged to permit the insertion therein of said operating part of the respective pedicular screw, has a conical free end portion remote from said grip and tapering in a direction toward said grip, and defines at least one longitudinal slot, and a tube freely slidably mounted on said rod of said device so as to be capable of surrounding and gripping said conical free end portion of said tubular end part for causing it to grip said operating part of said pedicular screw.
9. Instrumentation according to claim 5 in combination with an ancillary device for screwing each pedicular screw by a part thereof, termed operating part, outside said region of penetration of said pedicular screw in said pedicle, said ancillary device comprising a rod provided with an end grip and a tubular end part which is arranged to permit the insertion therein of said operating part of the respective pedicular screw, has a conical free end portion remote from said grip and tapering in a direction toward said grip, and defines at least one longitudinal slot, and a tube freely slidably mounted on said rod of said device so as to be capable of surrounding and gripping said conical free end portion of said tubular end part for gripping and tightening a nut.
10. Instrumentation according to claim 9, wherein said ancillary device comprises, in said tubular end part and beyond said conical free end portion, a hollow profile matching said profiled end portion of said pedicular screw so as to prevent rotation of said pedicular screw relative to said tubular end part.
11. Instrumentation according to claim 10, wherein said hollow profile defines two flats having parallel surfaces and said profiled end portion of said pedicular screw defines two flats having parallel surfaces cooperative with said two flats of said hollow profile.
12. Instrumentation according to claim 10, wherein said hollow profile is extended in a direction toward said conical free end portion by longitudinal recesses for receiving said second screw thread of said pedicular screw.
13. Instrumentation according to claim 10, comprising a transverse opening in said tubular end part in the region of said hollow profile for a visual checking of the engagement of said pedicular screw with said hollow profile for preventing relative rotation.
14. Pedicular screw for use in an osteosynthesis instrumentation said pedicular screw comprising a first screw thread and a second screw thread and a transverse shoulder interposed between said two screw threads for supporting a connection element forming part of said instrumentation, said first screw thread being for screwing into the pedicle of a vertebra and having an end thread helix which fades tangentially on a cylindrical sector of said transverse shoulder.
15. Ancillary device intended for an osteosynthesis instrumentation for screwing a pedicular screw which forms part of said instrumentation and comprises a first screw for screwing into the pedicle of a vertebra and a second screw constituting an operating part, said ancillary device comprising a rod which has a tubular end part and terminates in an end grip, said tubular end part being so dimensioned as to permit the insertion therein of said operating part of said pedicular screw, said tubular end part having a conical free end portion remote from said grip which tapers in a direction toward said grip, and at least one longitudinal slot, said ancillary device further comprising a tube freely slidably mounted on said rod of said ancillary device for the purpose of surrounding and gripping said conical end portion of said tubular end part and causing it to grip said operating part of said pedicular screw.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9213694A FR2697991B1 (en) | 1992-11-13 | 1992-11-13 | Lumbosacral osteosynthesis instrumentation for the correction of spondylolisthesis by posterior route, and instrumentation screws. |
| FR92/13694 | 1992-11-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2149322A1 true CA2149322A1 (en) | 1994-05-26 |
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ID=9435531
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002149322A Abandoned CA2149322A1 (en) | 1992-11-13 | 1993-11-12 | Pedicular screw and posterior spinal instrumentation |
Country Status (13)
| Country | Link |
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| EP (1) | EP0668750A4 (en) |
| JP (1) | JP3737825B2 (en) |
| KR (1) | KR950703899A (en) |
| CN (1) | CN1092637A (en) |
| AR (1) | AR248078A1 (en) |
| AU (1) | AU682839B2 (en) |
| CA (1) | CA2149322A1 (en) |
| FI (1) | FI952312A (en) |
| FR (1) | FR2697991B1 (en) |
| NO (1) | NO951900L (en) |
| TW (1) | TW314459B (en) |
| WO (1) | WO1994010928A1 (en) |
| ZA (1) | ZA938465B (en) |
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| FR2716794B1 (en) * | 1994-03-03 | 1996-05-24 | Sofamor Danek Group Inc | Connector for spinal osteosynthesis instrumentation, intended for lumbar or sacral or iliosacral fixation. |
| FR2740673B1 (en) * | 1995-11-07 | 1998-01-23 | Stryker France Sa | TRANSVERSE CONNECTION DEVICE AND ASSEMBLY FOR OSTEOSYNTHESIS OF THE RACHIS |
| FR2761876B1 (en) * | 1997-04-09 | 1999-08-06 | Materiel Orthopedique En Abreg | INSTRUMENTATION OF LUMBAR OSTEOSYNTHESIS FOR CORRECTION OF SPONDYLOLISTHESIS BY POSTERIOR PATHWAY |
| FR2768610B1 (en) * | 1997-09-22 | 1999-12-10 | Materiel Orthopedique En Abreg | BONE SCREW FOR OSTEOSYNTHESIS DEVICES, AND METHOD FOR MANUFACTURING THE SAME |
| WO1999060837A2 (en) | 1998-05-27 | 1999-12-02 | Nuvasive, Inc. | Bone blocks and methods for inserting |
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| US6251140B1 (en) | 1998-05-27 | 2001-06-26 | Nuvasive, Inc. | Interlocking spinal inserts |
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| FR2801777B1 (en) | 1999-12-03 | 2002-02-08 | Spinevision | EXTERNAL FIXATOR IN THE FIELD OF RACHIDIAN OSTEOSYNTHESIS AND GENERAL ORTHOPEDICS |
| DE20010206U1 (en) * | 2000-06-09 | 2001-10-18 | BIOMET MERCK Deutschland GmbH, 14167 Berlin | Holder for a pedicle screw |
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| FR2856581B1 (en) * | 2003-06-27 | 2005-08-19 | Medicrea | MATERIAL OF VERTEBRAL OSTEOSYNTHESIS |
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| US8083796B1 (en) | 2008-02-29 | 2011-12-27 | Nuvasive, Inc. | Implants and methods for spinal fusion |
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| CN103519878B (en) * | 2013-10-29 | 2016-03-23 | 宋西正 | A kind of Wicresoft sled dials shaping inner fixer |
| CN111887967A (en) * | 2013-10-31 | 2020-11-06 | 爱荷华大学研究基金会 | Percutaneous transconnector system |
| KR101537062B1 (en) * | 2014-08-11 | 2015-07-16 | 주식회사 코렌텍 | An apparatus for fixing vertebra |
| EP3417818A4 (en) * | 2016-02-15 | 2019-10-23 | ASRO Medical | Transverse, and surgical instrument |
| US10420593B2 (en) * | 2016-07-21 | 2019-09-24 | Warsaw Orthopedic, Inc. | Spinal correction system and method |
| CN107307899A (en) * | 2016-12-31 | 2017-11-03 | 王文军 | Multi-segmental tandem spinal external fixator |
| US20180228516A1 (en) * | 2017-02-14 | 2018-08-16 | Warsaw Orthopedic, Inc. | Spinal implant system and method |
| CN106963462A (en) * | 2017-03-23 | 2017-07-21 | 张群 | External fixer for operation on vertebra |
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| FR3124692B1 (en) * | 2021-07-01 | 2023-12-08 | Distimp | Bone anchoring screw for osteosynthesis device, surgical assembly for connecting said screw to said osteosynthesis device, and set of instruments for installing said surgical assembly. |
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| ES2034058T3 (en) * | 1987-07-29 | 1993-04-01 | Acromed Corporation | A DEVICE IMPLANTABLE BY SURGICAL MEANS FOR THE SPINAL COLUMN. |
| US4836196A (en) * | 1988-01-11 | 1989-06-06 | Acromed Corporation | Surgically implantable spinal correction system |
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-
1992
- 1992-11-13 FR FR9213694A patent/FR2697991B1/en not_active Expired - Lifetime
-
1993
- 1993-11-12 CA CA002149322A patent/CA2149322A1/en not_active Abandoned
- 1993-11-12 JP JP51238294A patent/JP3737825B2/en not_active Expired - Fee Related
- 1993-11-12 WO PCT/US1993/010966 patent/WO1994010928A1/en not_active Application Discontinuation
- 1993-11-12 KR KR1019950701968A patent/KR950703899A/en not_active Application Discontinuation
- 1993-11-12 EP EP94902235A patent/EP0668750A4/en not_active Ceased
- 1993-11-12 AU AU56676/94A patent/AU682839B2/en not_active Ceased
- 1993-11-12 AR AR93326571A patent/AR248078A1/en active
- 1993-11-12 CN CN93121427A patent/CN1092637A/en active Pending
- 1993-11-12 ZA ZA938465A patent/ZA938465B/en unknown
-
1994
- 1994-05-04 TW TW083104029A patent/TW314459B/zh active
-
1995
- 1995-05-12 FI FI952312A patent/FI952312A/en not_active Application Discontinuation
- 1995-05-12 NO NO951900A patent/NO951900L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| KR950703899A (en) | 1995-11-17 |
| AU682839B2 (en) | 1997-10-23 |
| ZA938465B (en) | 1994-09-15 |
| EP0668750A4 (en) | 1996-04-10 |
| FR2697991B1 (en) | 1995-02-03 |
| AR248078A1 (en) | 1995-06-30 |
| FI952312A0 (en) | 1995-05-12 |
| FI952312A (en) | 1995-05-12 |
| FR2697991A1 (en) | 1994-05-20 |
| AU5667694A (en) | 1994-06-08 |
| EP0668750A1 (en) | 1995-08-30 |
| JP3737825B2 (en) | 2006-01-25 |
| NO951900D0 (en) | 1995-05-12 |
| JPH08505785A (en) | 1996-06-25 |
| WO1994010928A1 (en) | 1994-05-26 |
| CN1092637A (en) | 1994-09-28 |
| TW314459B (en) | 1997-09-01 |
| NO951900L (en) | 1995-06-16 |
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