Method Of Implanting An Interspinous Vertebral Implant
According to certain embodiments, disclosed is a vertebral interspinous implant including first and second supports (2,3) defining in their center part respective fixation bodies (7,8) to accept spinal processes of two respective vertebrae, these fixation bodies being located in a same sagittal plane, first and second elastically compressible bodies (4) being set between the first and second supports (2,3) and on each side of the said sagittal plane (P), first and second rigid guides (10) around which are arranged, respectively, the first and second elastically compressible bodies (4), each of these guides (10) optionally being connected at one of its extremities to the supports (2,3) and including at, at least, one of its extremities an abutment (13) adapted to cooperate with an abutment(14) of the corresponding support (3) in order to limit the separation of the supports (2,3) in the direction of the spine.
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This application is a divisional of U.S. Ser. No. 12/124,801, filed May 21, 2008, which claims priority of the filing date of European Patent Application No. 07010112.6, filed May 22, 2007, both of which are hereby incorporated by reference.
TECHNICAL FIELDDisclosed is an interspinous vertebral implant, meaning an implant intended to be inserted between the spinal processes of two adjacent vertebrae, in order to function as a stabilizer and notably relieve the inter-vertebral disk.
BACKGROUNDIt is known through U.S. Patent Application Publication No. 2002/0143331, FIG. 9, of an interspinous vertebral implant including first and second supports defining fixation bodies to respective adjacent spinal processes and in between which is placed, an elastic body of annular shape and coaxial with the supports. The elastic body is placed between the bottom of an annular cavity of the first support and an annular male body of the second support which is axially guided in this cavity. The peripheral wall of the first support includes an internal annular protuberance which can cooperate with an annular shoulder of the male body of the second support in order to limit the gaps of the supports. The face of the extremity of the peripheral wall of the first support constitutes also a stop which can cooperate with an edge of the second support in order to limit the compression of the elastic body.
According to U.S. Patent Application Publication No. 2002/0143331, this implant presents several disadvantages. At first instance, it can be noted that this implant and its elastic body have a circular shape. To obtain a certain capacity of shock absorption, the elastic body must have sufficient dimensions. Yet if the diameter of the implant is increased, its overloading in the antero-posterior direction will be too great and will necessitate the damaging, in too great of a measure, of the vertebral tissues for the setting in place of the implant. On another hand, the presence of the annular male body of the second support and of the peripheral wall of the first support limit in great fashion, the space available for the elastic body. Another disadvantage is that the stops which limit the gaps of the supports appear undersized in order to really resist to physiological loads.
FR Patent Application No. 2 774 581, diagram 4, describes an interspinous vertebral implant consisting of first and second supports defining in their center part respective fixation bodies for spinal processes of two respective vertebrae, these fixation bodies being located in the same sagittal plane, and first and second elastically compressible bodies in the direction of the spine, these elastically compressible bodies being put in place between the first and second supports and on both sides of the aforementioned sagittal plane.
The elastically compressible bodies are in the shape of bellows defining waterproof inner walls filled with a liquid and a core made in a viscoelastic material. This implant according to FR 2 774 581 seems to present a greater capacity of shock absorption than the one described in the document U.S. Patent Application Publication No. 2002/0143331. However, this implant appears to be difficult to achieve because its extremities of the bellows must be solidly fastened to the supports in order to maintain the inner walls waterproofed and to avoid the separation of the supports from one another. Yet, FR 2 774 581 does not explain how to fasten the bellows to the supports. This problem of bellows' fixation to the supports is that much more critical, given that the implant does neither comprise any stops to limit the supports gap nor to limit the bellows' compression. It is important to also note that the viscoelastic cores are not really guided and therefore susceptible to move laterally, which can unbalance the implant and perturb the functioning of the bellows.
SUMMARYThe present implant aims to remedy to the aforementioned disadvantages of the state of the art and discloses An interspinous vertebral implant comprising at least two supports defining in their center part respective fixation bodies to accept spinal processes of two respective vertebrae, said fixation bodies being located in the same plane of symmetry; at least two elastic bodies that are elastically compressible in the direction of the spine, said elastically compressible bodies being arranged between said supports and on each side of said plane; at least two rigid guides engaged with said supports, wherein at least one of its extremities comprises an abutment to cooperate with an abutment of the corresponding support to limit the separation of said at least two supports in the direction of the spine.
According to certain illustrative embodiments, the interspinous vertebral implant comprises at least first and second supports defining in their center part respective fixation bodies to accept spinal processes of two respective vertebrae, said fixation bodies being located in the same sagittal plane; at least first and second elastic bodies that are elastically compressible in the direction of the spine, said elastically compressible bodies being arranged between said supports and on each side of said sagittal plane; at least first and second rigid guides being engaged with said supports, wherein at one of its extremities comprises an abutment to cooperate with an abutment of the corresponding support to limit the separation of said supports in the direction of the spine.
According to certain illustrative embodiments, the interspinous vertebral implant comprises first and second supports defining in their center part respective fixation bodies to accept spinal processes of two respective vertebrae, said fixation bodies being located in the same sagittal plane; first and second elastic bodies that are elastically compressible in the direction of the spine, said elastically compressible bodies being arranged between said first and second supports and on each side of said sagittal plane; first and second rigid guides around which are arranged, respectively, said first and second elastically compressible bodies, each of said first and second guides being connected at one of its extremities to one of said supports and at least one of its extremities comprising an abutment to cooperate with an abutment of the corresponding support to limit the separation of said first and second supports in the direction of the spine.
Thus, the rigid bodies insure, both, a function of guidance and a function of stop. This design allows the elastic bodies will stay properly in place within the implant and to give a great sturdiness to the stops. The implant can present a light overload in the antero-posterior direction, which can allow, notably, to keep a good portion of the natural ligaments. The overload of the implant in the lateral direction is a bit impeding since the corresponding tissues are mostly made up of muscle.
Also disclosed is an implant comprising at least two supports defining in their center part respective fixation bodies to accept portions of adjacent bones, said fixation bodies being located in the same anatomical plane; at least two elastically compressible bodies arranged between said supports and on each side of said anatomical plane; and at least two rigid guides engaged at its extremities to said supports and at least one of its extremities comprising an abutment to cooperate with an abutment of the corresponding support to limit the separation of said supports.
According to certain illustrative embodiments, the implant comprises at least first and second supports defining in their center part respective fixation bodies to accept portions of adjacent bones, said fixation bodies being located in the same sagittal plane; at least first and second elastically compressible bodies arranged between said supports and on each side of said sagittal plane; and at least first and second rigid guides being engaged with said supports, wherein at one of its extremities comprises an abutment to cooperate with an abutment of the corresponding support to limit the separation of said supports.
According to further illustrative embodiments, the implant comprises first and second supports defining in their center part respective fixation bodies to accept a portions of adjacent bones, said fixation bodies being located in the same sagittal plane; first and second elastically compressible bodies arranged between said supports and on each side of said sagittal plane; first and second rigid guides around which are arranged said elastically compressible bodies, each of said guides being connected at one of its extremities to said supports and at least one of its extremities comprising an abutment to cooperate with an abutment of the corresponding support to limit the separation of said first and second supports.
Additionally disclosed is a method of implanting an interspinous vertebral implant having at least one elastically compressible body into a space between two adjacent vertebrae comprising resecting at least a portion of either one or both of ligament and soft tissue to expose said space; and inserting the interspinous vertebral implant having at least one pre-loaded elastically compressible bodyunder compression into the space between the two adjacent vertebrae.
Some illustrative embodiments of the presently disclosed interspinous vertebral implant are described hereinafter and defined in the dependant claims.
Other characteristics and advantages of the presently disclosed interspinous vertebral implant will be evident by the reading of the following detailed description of several illustrative embodiments of the interspinous vertebral implant made in reference to the annexed drawing figures.
In reference to diagrams
The elastic bodies 4 are aligned in the lateral direction and located on each side of the sagittal plane of symmetry (P). The elastic bodies 4 are elastically compressible in the direction of the spine (vertical direction P on
According to certain illustrative embodiments, the section of each bore 15 is bigger than the outer diameter of the corresponding guiding rod 10 in order to leave a clearance 14a between the walls of the bores 15 and the guiding rods 10 to allow inclination movements of the supports 2,3 one in comparison to the other in the frontal plane (lateral flexion movements of the patient) or in the sagittal plane (flexion/extension movements of the patient) as well as axial rotation movements of the supports 2,3 one in comparison to the other (torsion), all these movements having a limited amplitude through the walls of the bores 15.
According to certain illustrative embodiments, the guiding rods 10 are screwed in a manner, to sufficiently bring nearer the supports 2,3 so that the elastic bodies 4 be in a pre-strained or pre-loaded state before the installation of the implant. Such pre-strain allows the implant to withstand loads up to a certain threshold without added compression of the elastic bodies 4. It is notably possible to choose the pre-strained state in such a fashion that once the implant is put in place, it can be able to withstand the loads exercised by the spine, when the patient is in the erect position, without added compression of the elastic bodies 4. This guarantees the efficient maintaining of the spinal processes' gap.
According to alternative embodiments, the guiding rods' 10 extremities 11a could be fastened in the support 2 in another manner other than by screwing, for example, without limitation, by driving out, bonding or welding. By the term “fastened” one means a fixation which maintains axially the immobile extremities 11a in comparison to the support 2 during the movements relative of the supports 2,3.
In addition, the implant 1 comprises, according to certain illustrative embodiments, two blocks 16 which protrude facing each other on the interior respective faces of the plates 5,6, in the center part of the implant 1, between the elastic bodies 4. These blocks 16 can act as an abutment or stop, against one another during extension movements of the patient to limit the compression of the elastic bodies 4 and thus protect these latter.
As one can see on
Also disclosed is a method of implanting the interspinous vertebral implant having at least one elastically compressible body into a space between two adjacent vertebrae within the spine. The method involves removal of at least portions of certain ligaments and soft tissue to expose or otherwise gain access to the target implant site. According to certain embodiments, at least a portion of the interspinous ligament and soft tissue are resected to expose the target implant site. In some instances, it may be necessary or beneficial to also resect at least a portion of the supraspinous ligament as well. Once the target implant site has been prepared by resection of the necessary ligaments and soft tissue, the interspinous vertebral implant is inserted into the target implant site.
The pre-loaded interspinous vertebral implant is implanted under compression into the target site between two adjacent vertebrae. This is generally accomplished by implanting an interspinous vertebral implant having at least one elastically compressible body which permits the implant to be implanted under compression. Illustrative implants 1, 20 and 30 disclosed herein each comprises at least one elastically compressible body and are able to be implanted under compression into the target site between two adjacent vertebrae. Implanting the interspinous vertebral implant into the target implant site under compression avoids having to cut or otherwise resect bony portions of the spinous processes of the adjacent vertebrae.
The interspinous vertebral implant may be implanted under compression with an appropriate surgical instrument or tool. The surgical instrument engages the interspinous vertebral implant and maintains the desired level of compression during the implantation into the target site. Because the implant is implanted under compression, the implant is maintained in proper position and the risk of implant migration is minimized or avoided.
The method of implanting the interspinous vertebral implant includes securing the interspinous vertebral implant to the superior and inferior spinous processes of the two adjacent vertebrae. Securing the implant to the spinous processes generally includes securing by means of at least one synthetic ligament. According to certain embodiments, the implant is secured to the spinous processes by means of two synthetic ligaments. An illustrative method for securing the implant to the spinous processes is described in further detail below with reference to
Traditionally, such synthetic ligaments are stopped and gathered to each other with knots. According to a characteristic of the process of installation of the implant, a part 45 is used to stop and gather the end parts of a ligament without knotting. This part is shown on
As represented
The described interspinous vertebral implant experiences no pre-loading at the neutral points in flexion, extension, lateral bending and axial rotation and therefore permits a balanced and controlled range of motion.
According to certain embodiments, provided is an implant for insertion between two adjacent bones. The implant comprises at least two supports defining in their center part respective fixation bodies to accept a portions of adjacent bones and being located in the same anatomical plane, at least two elastically compressible bodies arranged between the supports and on each side of the anatomical plane, and at least two rigid guides engaged with the supports. According to certain embodiment, the elastically compressible bodies are arranged or otherwise disposed around the rigid guides. Depending on the embodiment, each of the guides may be connected at one of its extremities to the supports and at least one of its extremities comprising an abutment to cooperate with an abutment of the corresponding support to limit the space between the supports.
The implant may comprise first and second supports defining in their center part respective fixation bodies to accept a portions of adjacent bones and being located in the same anatomical plane, first and second elastically compressible bodies arranged between the first and second supports and on each side of the anatomical plane and first and second rigid guides. The elastically compressible bodies may be arranged or otherwise disposed around the rigid guides. Each of the rigid guides may be connected at one of its extremities to the supports and at least one of its extremities comprising an abutment to cooperate with an abutment of the corresponding support to limit the space between the first and second supports.
The abutments of the guides of the implant maintain the elastically compressible bodies in a pre-loaded state. The implant also includes a clearance between each guide and at least one of said first and second supports to allow relative inclination and axial rotation movement of the supports.
According to certain embodiments, the supports define in a central zone, located between elastically compressible bodies, a female part comprising a bore and a male part to slide axially in the bore with a clearance allowing relative inclination movements of supports. The male part section and the bore section have a non-circular shape to limit relative axial rotation movements of supports, and the clearance is smaller than the clearance between the guide and the supports such that the relative inclination and axial rotation movements are limited by the assembly of male and female parts and not by the assembly of the guide and supports.
The guides of the implant may be fastened at one of their extremities in one of supports and have an abutment at the other extremity. According to other embodiments, at least one of the extremities of each of at least one of the guides has a spherical shape favoring an inclination of supports, one in comparison to the other.
The supports of the implant may also further define respective stops located between the elastically compressible bodies and being able to come in contact with each other, to limit the compression of the elastically compressible bodies.
The supports may be in the shape of plates intended to be placed between spinal processes and having said fixation bodies. The fixation bodies each define a casing that is intended to receive a portion of a bone. The distance (d) between the respective bottoms of the casings is substantially equal to the height (h) of the elastically compressible bodies, or the distance (d) may be inferior to the height (h).
While the interspinous vertebral implant and process for implanting the same have been described in connection with various illustrative embodiments, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function disclosed herein without deviating therefrom. The embodiments described above are not necessarily in the alternative, as various embodiments may be combined to provide the desired characteristics. Therefore, the implant and process for implanting the same should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.
Claims
1. A method of implanting an interspinous vertebral implant having at least one elastically compressible body into a space between two adjacent vertebrae comprising:
- resecting at least a portion of either one or both of ligament and soft tissue to expose said space; and
- inserting the interspinous vertebral implant having at least one pre-loaded elastically compressible body under compression into the space between the two adjacent vertebrae.
2. The of implanting an interspinous vertbral implant of claim 1, wherein resecting at least a portion of one or both of ligament and soft tissue comprises resecting at least a portion of the intespinous ligament.
3. The method of implanting an interspinous vertebral implant of claim 2, further comprising resecting at least a portion of the supraspinous ligament.
4. The method of implanting an interspinous vertebral implant of claim 1, wherein the inserting the interspinous vertebral implant occurs without resecting bony portions of the spinous processes of the adjacent vertebrae.
5. The method of implanting an interspinous vertebral implant of claim 1, further comprising resecting soft tissue adjacent the two adjacent vertebrae.
6. The method of implanting an interspinous vertebral implant of claim 2, further comprising resecting soft tissue adjacent the two adjacent vertebrae.
7. The method of implanting an interspinous vertebral implant of claim 3, further comprising resecting soft tissue adjacent the two adjacent vertebrae.
8. The method of implanting an interspinous vertebral implant of claim 1, further comprising securing the interspinous vertebral implant to the superior and inferior spinous processes with at least one synthetic ligament.
9. The method of implanting an interspinous vertebral implant of claim 1, further comprising securing the interspinous vertebral implant to the superior and inferior spinous processes with two synthetic ligaments.
10. The method of implanting an interspinous vertebral implant of claim 3, further comprising rejoining ends of the resected supraspinonus ligament.
Type: Application
Filed: Sep 13, 2011
Publication Date: Jan 5, 2012
Applicant: Eden Spine, LLC (Lake Mary, FL)
Inventors: Mourad Ben-Mokhtar (Geneva), Jean-Marc Fuentes (Montpellier)
Application Number: 13/231,203