3 4
FIG. 6 is a plan view of a second embodiment of a out below. Implant 14 is preferably constructed of any
stabilizer constructed in accordance with the present inven- durable, relatively biologically inert substance such as car
tion. bon fiber, titanium, several medical grade hard plastics, and
FIG. 7 is a projected view of the applicator of the such other materials as are known in the art for use in such
stabilizer of FIG. 6 after detaching the implant therefrom. 5 implants.
FIG. 8 is a projected view of the implant of the stabilizer Referring now to FIGS. 4 and 5, there is shown a spreader,
of FIG. 6 after being detached from the applicator. indicated generally at reference numeral 48, having integral
FIG. 9 is a longitudinal, sectional view of a portion of the handle 50 and ^^nt 52 portions sized and generally
stabilizer of FIG. 6, taken along the lines 9—9 in FIG. 6. shaPed in tile same size md dimensions as the stabilizer 10.
Xtt/" 1 n •„ „• ,„ „f „r o„ m The use of the stabilizer 10 of the present invention in, for
FIG. 10 is a projected view or another embodiment of an iu . x ^j^i i_ • * ^uij-i
i * * J • j vwi. *• instance, a method of lumbar intervertebral disk
implant constructed in accordance with the present invention ..... ..' ,„_.„„ . .„ ..... = c
o^i ,„uivh io „«.»h ;„ ~io„„ „f jTM„io.,t%,f iTM- i stabilization, or LIDS . is illustrated in FIG. 5. Surgery is
and which is used in place oi the implant or rIG. 3. . . , , . iU . ^ ° ; ,
__ v . . - ,. , „. performed as in a simple diskectomy and the intervertebral
FIG. 11 is an exploded, projected view of a third embodi- 54 is exposed through a small laminotomy. The disk
ment of a stabilizer constructed in accordance with the materfal is removed md any nerve root compression is
present invention. 15 corrected The posterior longitudinal ligament and disk
FIG. 12 is a plan view of a spreader which is used to cartilage are removed until the surfaces of the bodies 60 and
advantage in connection with the insertion of the implant of $2 0f adjacent vertebrae 56 and 58, respectively, are exposed
the stabilizer of FIG. 11 between two adjacent vertebrae of above and below the disk space.
a patient's spinal column. Using ^ spreader 48; the vertebrae 56 and 58 are
DFTATT ,FD DESQilPTION OF THE 20 distracted to open the disk space, and once the desired
PREFERRED EMBODIMENT "spread" has been achieved, the middle portion of the disk
space is packed with cancellous bone chips (not shown). As
Referring now to the figures, multiple embodiments of the described below, a kit of several spreaders, each having present invention will be illustrated and described in more progressively larger diameter implant portions, is used to detail. Specifically with regard to the embodiment shown in 25 achieve the desired spread. Because the posterior longituFIG. 1, the stabilizer is indicated generally at reference dinal ligament is left intact to the opposite side and to the numeral 10, and is comprised of two parts, an applicator 12 center of the disk space, the bone chips are held in place in and an implant 14. Applicator 12 is shown with a handle 16 the disk space. The appropriately-sized implant 14 of stain the shape of a "T", but it will be recognized from this bilizer 10 is then inserted into the disk space using the disclosure by those skilled in the art that the handle 16 may 30 applicator 12 until the threads 46 formed on the outside take the form of any convenient hand grip or other structure surface of implant 14 engage the bodies 60 and 62 of the which facilitates the handling of the stabilizer 10 and adjacent vertebrae 56 and 58, respectively. Piston 22 is then subsequent rotation of the stabilizer 10 once the implant 14 wedged into the bore 20 to cause the applicator 12 to has been inserted into the space between two adjacent frictionally engage implant 14 to prevent relative rotational vertebrae as more particularly described below. movement therebetween and the stabilizer 10 is rotated.
As shown more clearly when FIG. 1 is viewed in con- Rotation of the implant 14 in the disk space causes the
junction with FIGS. 2 and 3, applicator 12 is comprised of threads 46 to bear against the bodies 60 and 62 to move the
an elongate mandrel 18 having a longitudinal bore 20 implant further into (or back out of, depending upon the
therethrough, the bore 20 terminating in a point, with an direction of rotation) the disk space in an anterior-posterior
elongate piston 22 disposed therein. Piston 22 is provided direction so as to enable the implant 14 to be positioned in
with a wedge-shaped, or pointed, end 24 which is sized to 40 the disk space at a position in which the expanded, or larger
approximate the shape of the pointed end of the bore 20 in diameter portion 44 and the smaller diameter ends 40 and 42
mandrel 18 at one end and a handle 26 formed at the other of implant 14 contact the respective lower and upper sur
end. As best shown in FIG. 2, the end 28 of mandrel 18 is faces of the bodies 60 and 62 of the adjacent vertebrae 56
provided with screw threads 30 which mate with the threads and 58. The respective lower and upper surfaces of the
32 (see FIG. 3) formed in the interior wall of the bore 34 in 45 vertebral bodies 60 and 62 are slightly concave such that the
implant 14. In this manner, the end 28 of mandrel 18 is expanded middle portion 44 of implant 14 allows the
received in and affirmatively engages the implant 14 to implant 14 to engage substantially more of the respective
detachably mount implant 14 to applicator 12. Applicator 12 surfaces of the vertebral bodies 60 and 62 than conventional
is provided with means for preventing relative rotational prosthetic devices, thereby providing increased stability to
movement between the implant 14 and applicator 12 50 the fusion.
comprised, in the preferred embodiment shown, of a plu- Once positioned in the disk space so as to provide
rality of radially spaced, longitudinal slots 36 in the end 28 maximum stabilization, pressure on the piston 22 is released
of mandrel 18 communicating with the longitudinal bore 20 and the piston 22 is backed out of the bore 34 so as to allow
therethrough and the wedge-shaped end 24 of piston 22. the applicator 12 to be rotated without rotating the implant
When piston 22 is forced down into the bore 20 in mandrel J5 14. The applicator is then detached from the implant 14 by
18, the pointed end 24 of piston 22 acts to spread, or force unscrewing and backed out of the incision in the patient If
the portions 38.of the threaded end of mandrel 18 between necessary, a small amount of a physiologically compatible
slots 36 outwardly into increasingly tighter frictional adhesive of a type known in the art is applied over the
engagement with the interior wall of the bore 34 of implant cancellous bone chips just medial to the implant to close off
34, thereby preventing relative rotational movement of the the remaining portion of the opening into the disk space. The
implant 14 and applicator 12. 60 patient should be able to ambulate soon after the LIDS
Implant 14 is formed in the shape of a generally elongate procedure because of the stability imparted to the spinal
cylinder with a blunt, or rounded end 40 and the end 42 column by the implant of the present invention. Before
having the aforementioned bore 34 opening therein. The narrowing of the disk space occurs, the cancellous bone
diameter of the ends 40 and 42 is smaller than the diameter chips will have started the fusion process,
of the middle portion 44 of the implant for a purpose to be 65 The stabilizer 10 is also used to advantage to perform, for
explained below. The outside surface of implant 14 is instance, a posterior lateral intertransverse fusion. The
provided with threads 46, the function of which are also set implant 14 is inserted into the region of the disk space from
