Intervertebral prosthesis or disk prosthesis

Abstract

An intervertebral prosthesis or disk prosthesis comprising a front side, a rear side, an upper side which can be placed on the base plate of vertebral body, a lower side which can be placed on the base plate of a vertebral body, a right side, a left side, a cavity which can receive a fluid hydraulic osteocementum, an opening in the cavity and several outlets out from the cavity. The total of the transversal surfaces of the outlets S.sub.V on the front side, the total of the transversal surfaces of the outlets S.sub.H on the rear side, the total of the transversal surfaces of the outlets S.sub.R on the right side and the total of the transversal surfaces of the outlets on the left side satisfy the following conditions: S.sub.L>S.sub.R or S.sub.R>S.sub.L or S.sub.H>S.sub.V or S.sub.V>S.sub.H.

Claims

1. A surgical method, comprising: implanting a first intervertebral spacer in a disc space defined between an upper vertebra and a lower vertebra, wherein the first spacer comprises: an upper side in contact with at least a portion of the upper vertebra; a lower side in contact with at least a portion of the lower vertebra; an anterior side facing towards an anterior portion of the disc space; a posterior side facing towards a posterior portion of the disc space; a first lateral side extending between the upper and lower sides and between the anterior and posterior sides; and a second lateral side extending between the upper and lower sides and between the anterior and posterior sides; implanting a second intervertebral spacer in the disc space defined between the upper vertebra and the lower vertebra, wherein the second spacer comprises: an upper side in contact with at least a portion of the upper vertebra; a lower side in contact with at least a portion of the lower vertebra; an anterior side facing towards the anterior portion of the disc space; a posterior side facing towards the posterior portion of the disc space; a first lateral side extending between the upper and lower sides and between the anterior and posterior sides; and a second lateral side extending between the upper and lower sides and between the anterior and posterior sides; wherein the first and second spacers are positioned such that the second lateral side of the first spacer faces the first lateral side of the second spacer; wherein the first and second spacers are spaced a distance apart from one another; and conveying a volume of flowable material to the first spacer, the flowable material flowing into an inlet opening of the first spacer, through a cavity of the first spacer, out of at least one of the first and second lateral sides of the first spacer, and into a central region of the disc space disposed between the first and second spacers, wherein a greater amount of the flowable material emerges from one of the first and second lateral sides of the first spacer than from an opposing lateral side of the first spacer.

2. The method of claim 1, wherein the flowable material emerges asymmetrically from the first spacer.

3. The method of claim 1, wherein the first spacer comprises a rectangular hollow body.

4. The method of claim 1, wherein the first and second spacers have a rectangular cross section.

5. The method of claim 1, wherein the first and second spacers are substantially rectangular.

6. The method of claim 1, wherein the flowable material comprises osteocementum.

7. The method of claim 1, wherein the flowable material comprises bone replacement material.

8. A surgical method, comprising: implanting first and second intervertebral prostheses next to one another in an intervertebral disc space of a patient such that the first prosthesis is disposed in a left portion of the disc space and the second prosthesis is disposed in a right portion of the disc space, the first and second prostheses being spaced apart from one another, a right side of the first prosthesis being oriented in the direction of a left side of the second prosthesis; and delivering a flowable material into at least one of the first and second prostheses such that the flowable material flows into a region between the first and second prostheses, the flowable material emerging asymmetrically from said at least one prosthesis such that more of the flowable material emerges from one side of the at least one prosthesis than from an opposing side of that same prosthesis.

9. The method of claim 8, wherein the flowable material, after emerging from said at least one prosthesis, extends all the way from the first prosthesis to the second prosthesis.

10. The method of claim 8, wherein the flowable material spreads in an anterior-posterior direction within the region between the first and second prostheses after emerging from said at least one prosthesis.

11. The method of claim 8, wherein the right side of the first prosthesis and the left side of the second prosthesis are substantially straight and are oriented parallel to one another.

12. A surgical method, comprising: positioning first and second implants within a disc space of a patient, the first and second implants being separated from one another in a lateral direction by a central space, the central space being disposed between a substantially straight sidewall of the first implant and an opposite substantially straight sidewall of the second implant; delivering a flowable material into at least one of the first and second implants to cause the flowable material to emerge asymmetrically from the substantially straight sidewall of said at least one implant and into the central space such that more of the flowable material emerges from one side of the first implant than from an opposing side of that same implant, the flowable material spreading in an anterior-posterior direction within the central space.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention and further development of the invention are described in even greater detail by means of several examples and partially diagrammatic drawings, in which

(2) FIG. 1 shows a perspective view of an inventive, lens-shaped intervertebral implant,

(3) FIG. 2 shows a longitudinal section through the intervertebral implant of FIG. 1 along the central plane VIII-VIII,

(4) FIG. 3 shows a side view from the right of the intervertebral implant of FIG. 1,

(5) FIG. 4 shows a side view from the left of the intervertebral implant of FIG. 1,

(6) FIG. 5 shows a perspective view of an inventive intervertebral prosthesis, which is secured by means of cured osteocementum,

(7) FIG. 6 shows a plan view of the intervertebral prosthesis of FIG. 5,

(8) FIG. 7 shows a perspective view of a variation of the embodiment, using two intervertebral implants, the osteocementum securing the implant in their position relative to one another as well as to prevent migrating apart,

(9) FIG. 8 shows a plan view of the two intervertebral implants of FIG. 7,

(10) FIG. 9 shows a front view of a variation of the embodiments, in which the perforated intervertebral implant has a rectangular cross section and

(11) FIG. 10 shows a front view of a variation of the embodiment, in which the perforated intervertebral implant has a circular ring-shaped cross section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) The intervertebral prosthesis 1, shown in FIGS. 1 and 2, consists of a rectangular hollow body and has a front side 2, a rear side 3, an upper side 4 suitable for positioning against the baseplate of a vertebral body, a lower side 5 suitable for positioning against the baseplate of a vertebral body, a right side 6, a left side 7, a cavity 8 suitable for accommodating a flowable, hydraulic osteocementum, an inlet opening 9 into the cavity 8 and several outlet openings 10; 11; 12; 13 from the cavity 8. The upper side 4 and the lower side 5 converge toward the front side 2 as well as toward the rear side 3, so that a lens-like configuration of the intervertebral prosthesis results.

(13) As can be seen from FIG. 2, the cross section of the cavity 8 decreases in the shape of a cone as the distance from the inlet opening 9 increases.

(14) As shown in FIG. 3, there are three outlet openings 12 with areas F.sub.1, F.sub.2 and F.sub.3 in the right side 6 of the intervertebral prosthesis 1, so that the sum S.sub.R of the cross sectional surfaces of the outlet openings emerging the right side 6 is S.sub.R=F.sub.1+F.sub.2+F.sub.3.

(15) As shown in FIG. 4, there are two outlet openings 13 with the areas F.sub.4 and F.sub.5 in the left side 7 of the intervertebral prosthesis 1, so that the sum S.sub.L of the cross-sectional surfaces of the outlet openings emerging for the left side 7 is S.sub.L=F.sub.4+F.sub.5.

(16) It is important that the sum S.sub.L>S.sub.R, so that more osteocementum can emerge on the left side 7 of the intervertebral prosthesis 1 from the cavity 8 through the outlet opening 13 into the intervertebral space than from the right side 6.

(17) FIGS. 5 and 6 show how the osteocementum 20, emerging from the right side 6 and the left side 7 of the intervertebral prosthesis 1, is distributed. Because the sum S.sub.L of the cross sectional areas of the outlet openings 13 emerging on the left side 7 is larger, the amount of osteocementum 20, emerging on the left side 7 and curing, is also larger than that emerging on the right side 6 and curing.

(18) FIGS. 7 and 8 show a further embodiment, which consists of two inventive intervertebral prosthesis 1, which are disposed next to one another. The two intervertebral prostheses are positioned in such a manner, that the right side 6 of the intervertebral prosthesis 1, which is disposed on the left, is oriented in the direction of the left side 7 of the intervertebral prosthesis 1, which is disposed on the right. For the intervertebral prosthesis 1, disposed on the left, the condition S.sub.L>S.sub.R applies, whereas, for the intervertebral prosthesis 1, which is disposed on the right, the reverse applies, namely S.sub.R>S.sub.L. Due to this measure, less osteocementum 20 emerges in the space between the two intervertebral prostheses 1 than emerges to the right side of the intervertebral prosthesis 1 disposed on the right and to the left side 7 of the intervertebral prosthesis 1 disposed on the left.

(19) FIG. 9 shows a variation of the embodiment of an inventive intervertebral implant 1, which has a rectangular cross section and from which a larger amount of osteocementum 40 has emerged on the right side than on the left side.

(20) FIG. 10 shows a further variation of an embodiment of an intervertebral prosthesis 1, which has a circular cross section and for which the amount of osteocementum 40 emerging on the right side through the outlet openings 12 is larger than that emerging on the left side through outlet openings 13.