United States Patent [191
`Brantigan
`
`4,834,757
`[11] Patent Number:
`[45] Date of Patent: May 30, 1989
`
`[54] PROSTHETIC IMPLANT
`
`4,743,258 5/1988 Ikada et a1. ..................... .. 623/66 X
`
`[76] Inventor: John W. Brantigan, 2108
`Bramblewood La" Fremont’ Nebr‘
`68025
`[21] Appl, No; 173,923
`_
`[22] Filed:
`
`Mar. 28, 1988
`
`>
`
`[63]
`
`Related U.S., Application Data
`Continuation-impart of Ser. No. 5_,785,_Jan. 22, 1987,
`5S2$1331358$212,122.13‘22528031532513:
`in_p’art 8f Sen 1110 95,461, sep‘ 1’1’ 1987_
`
`OTHER PUBLICATIONS
`PoroCoat-—A Technical Review of Porous-Coated
`Implants for Biological Fixation-DePuy.
`Article “Anterior Discectomy and Interbody Fusion
`for Lumbar Disc Herniation”-—Inoue, MD. et al No.
`183, Mar. 1984.
`Article-—“Clinical Orthopaedics and Related Re
`Search” No_ 193 Man 1985_
`Ian-man, Examiner_Richard J_ Apley
`Examiner-Alan W
`Attorney, Agent, or FD‘m-Hlll, Van Santen, Steadman &
`S1mpson
`
`[56]
`
`References Cited
`
`[51] Int. Cl.4 .............................................. .. >A61F 2/44
`ABSTRACT
`[57]
`[52] us. c1. ...................................... ., 623/17; 623/16;
`128/92 YG; 128/92 YM Gauge blocks or plugs and permanent implant plugs are
`[58] Field of Search ..................... .. 623/17, 16, 18, 21,
`provided for surgical procedures to support and fuse
`623/22, 23, 66; 128/92 YG, 92 YM, 92 Y], 92
`together adjacent vertebrae in a vertebral column. The
`W, 305
`plugs are rectangular with tapered front ends and tool
`receiving rear ends. The gauge blocks are smooth faced
`for removal but the implant plugs have roughened sur
`faces to grip the vertebrae and provide channels for
`bone ingrowth. The plugs have recesses in the form of
`through slots to be packed with bone graft material. In
`the surgical procedure, undamaged annulus ?brosus
`disc tissue connecting the adjacent vertebrae is pre
`served and a pair of side-by-side roughened implant
`plugs are forced into side-by-side transverse channels in
`the adjoining vertebrae to stretch the remaining annulus
`disc tissue and form struts supporting the vertebrae.
`The plugs are bottomed in the channels on cortex bone
`and bone ingrowth is facilitated to fuse the plugs to the
`vertebrae.
`
`US. PATENT DOCUMENTS
`
`2,677,369 5/1954 Knowles .
`3,228,393 1/1966 Michele ......................... .. 128/92 YJ
`3,426,364 2/ 1969 Lumb .
`3,848,601 11/1974 Ma et al. ........................... .. 128/305
`3,855,638 12/1974 Pilliar .
`3,867,728 2/1975 Stubstad et a1. .
`3,871,031 3/1975 Boutin ............................. .. 623/18 X
`3,893,196 7/1975 HOchman ............................ .. 623/18
`4,206,516 6/1980 Pilliar .
`4,309,777 1/1982 Patil .
`4,349,921 9/1982 Kuntz ........................... ..' ..... .. 623/17
`4,550,448 11/1985 Kenna .
`4,553,273 1l/1985 Wu .
`4,559,086 7/1986 Doty .
`
`11 Claims, 2 Drawing Sheets
`
`

`

`I US. Patent May 30,1989
`. US. Patent May 30,1989
`1
`1
`4
`10
`
`Sheet 1 of2
`Sheet 1 of2
`
`4,834,757
`4,834,757
`
`
`
`

`

`US. Patent
`May 30, 1989
`FIGS
`
`Sheet 2 0f 2
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`4,834,757
`
`2.2a
`
`

`

`1
`
`PROSTHETIC IMPLANT
`
`4,834,757
`2
`transmitted through degenerated discs causing pain.
`Further, posterior fusion tends to cause bony over
`growth leading to nerve root compression by spinal
`stenosis.
`
`5
`
`(3) DISC EXCISION WITH ANTERIOR
`INTERBODY FUSION
`Interbody fusion techniques, in which the soft disc is
`completely excised and replaced with either the pa
`tient’s own bone (autologous bone) or with transplant
`banked bone (homologous bone) are generally success
`ful if solid fusion can be obtained between adjacent
`vertebrae bodies. Unfortunately, the success rate has
`only been about 50%.
`(4) DISC EXCISION WITH POSTERIOR
`LUMBAR INTERVERTEBRAL FUSION (PLIF)
`This procedure reconstructs the normal anatomic
`relationships between the bony and the neural struc
`tures and has many advantages. Weight bearing
`through a solid bony fusion mass between vertebral
`bodies relieves the mechanical pain of the traditional
`unstable degenerative disc and generally prevents long
`term disc collapse or further degenerative changes. The
`complete disc excision prevents recurrent herniation of
`the same degenerated disc.
`However, this PLIF procedure has several serious
`disadvantages in that it is technically very dif?cult, and,
`therefore, not as successful or widely used as it might
`be. It entails large amounts of blood loss in a small deep
`hole causing physiological stress to the patient and psy
`chological distress to the surgeon. Further, the use of
`autologous bone graft from the patient’s own iliac crests
`extends the operation and creates a second painful oper
`ative site. Because it is dif?cult to obtain a large enough
`quantity of autogenous bone with suf?cient strength,
`homologous bank bone is generally used.
`Interbody bone grafting involves the problems of
`strength and that of bone incorporation. Strong cortex
`bone (the outer layer) is required as a strut in the inter
`body position to prevent collapse of the disc space
`while healing occurs. The surgeon has the unfortunate
`requirement of having to fashion the required struts
`with handheld tools during the operation and these
`cortex bone struts are not wide enough for optimum
`load bearing and they anchor themselves by healing
`process that occurs very slowly over a matter of years.
`Further, soft cancellous bone, which heals more reli
`ably over a matter of 12 to 18 months, is also required
`. for a traditional interbody fusion.
`It is well understood in orthopaedic surgery, that
`grafted bone heals by a process called “creeping substi
`tution” in which blood capillaries ?rst grow into the
`grafted bone, the grafted bone is reabsorbed, and then
`new bone cells are laid down along the bony matrix of
`the graft. During the time that the structural bone grafts
`struts are being reabsorbed, motion must still be pre
`vented in the involved segments and although a brace
`or cast is often used, the entire process has proven less
`reliable than desired. Homologous bank bone, being
`more “foreign”, requires a much longer time to grow
`together and has a higher failure rate estimated at three
`times the failure as with the patient’s own bone. In
`effect, neither source of bone is optimum for the fusion
`procedure.
`My prior aforesaid U.S. Pat. No. 4,743,256 discloses
`an improved surgical procedure for eliminating spinal
`
`10
`
`20
`
`35
`
`45
`
`RELATED APPLICATIONS
`This application is a continuation-in-part of Ser. No.
`005,785, ?led Jan. 22, 1987, now U.S. Pat. No.
`4,743,256, which is a continuation of Ser. No. 784,112,
`?led Oct. 4, 1985, abandoned, and is also a continuation
`in-part of Ser. No. 095,461, ?led Sept. 11, 1987
`BACKGROUND OF THE INVENTION
`Field of the Invention
`This invention relates to the art of prosthetic devices
`and methods for implanting the devices between adja
`cent vertebrae to treat or prevent back pain in patients
`with ruptured or degenerated intervertebral discs. Spe
`ci?cally this invention deals with improvements in pros
`thetic strut forming plugs or blocks with roughened
`surfaces facilitating bone ingrowth from adjoining ver
`tebrae wherein the blocks are shaped to ?t in rectangu
`lar slots cut in the vertebrae, have heights which will
`stretch the remaining elastic annulus tissues of damaged
`discs between the adjoining vertebrae and have slots
`extending vertically, transversely or both vertically and
`transversely through the plugs to be packed with bone
`grafts to expedite the bone ingrowth.
`More speci?cally the plugs or blocks ?tting the rect
`angular slots in the adjoining vertebrae have tapered
`leading ends facilitating insertion into the slots between
`the vertebrae to stretch remaining disc tissue connect
`ing the vertebrae and tool receiving trailing ends for
`forcing the plugs into position. A still further speci?c
`feature of the invention is the provision of plugs which
`are radiolucent for improved X-ray visualization of the
`bone healing post-operatively.
`As pointed out in my aforesaid parent U.S. Pat. No.
`4,743,256 its continuation-impart application Ser. No.
`_ 095,461, the leading cause of low back pain arises from
`rupture or degeneration of lumbar intervertebral discs.
`Pain in the lower extremities of the back (sciatica) is
`caused by the compression of spinal nerve roots by
`damaged discs between the vertebrae and low back pain
`is caused by collapse of the disc and the adverse effects
`of bearing the majority of the body weight through a
`damaged unstable vertebrae joint. Surgical treatments
`for relief of the sciatic pain and lower back pain gener
`ally include the following:
`(I) EXCISION OF THE RUPTURED SOFT DISC
`This procedure removes the portion of the disc com
`pressing the spinal nerve and is generally successful in
`relieving the sciatic leg pain but in more than half of the
`cases, there is a recurrence of back pain. Over a period
`of time the disc gradually loses height clue to the rup
`ture and this loss of height causes the posterior facet
`joints of the vertebrae to fit incorrectly resulting in
`arthritic change in all elements of the spinal segment.
`Recurrent nerve root compression due to ‘bony en
`croachment (spinal stenosis) also develops, The con
`tinuing and recurring back pain from this source has
`created a leading source of pain and disability.
`
`(2) DISC EXCISION WITH POSTERIOR FUSION I
`Traditional posterior fusion, creating bone growth
`between the bony laminae, or postero-lateral fusion
`between the transverse processes prevents motion be
`tween the adjacent vertebrae but does not alter the fact
`that approximately 90% of the body weight must be
`
`65
`
`

`

`4,834,757
`3
`4
`polyacetal, polyethylene, and polysulfone type, prefera
`back pain caused by ruptured or degenerated vertebral
`discs by spanning the disc space between adjacent ver
`bly ?lled with glass or carbon ?bers. These plastics can
`tebrae with rigid implants having surfaces facilitating
`be injection molded, are light in weight, have great load
`carrying strength and provide improved x-ray visualisa
`bone ingrowth and bottomed on prepared sites of the
`vertebrae to integrate the implant with the vertebrae
`tion of bone healing. Fiber reinforced plastics composed
`and to provide a permanent weight supporting strut
`of such materials filled with glass or carbon ?bers are
`maintaining the disc space.
`also desirable. Suitable carbon ?ber composites are
`My prior aforesaid patent application Ser. No.
`supplied under the tradename “VICTREX P.E.S.”
`095,461, ?led Sept. 11, 1987, discloses a further im
`which is polyether sulfone ?lled with carbon ?bers.
`proved surgical procedure by providing the rigid im
`Suitable grades are “4101 G.L.-30” which is a 30 per
`plants or blocks with tool receiving end faces facilitat
`cent ?ber glass ?lled and “450 C.A.-30” which is a 30
`ing their insertion onto the prepared sites and having
`percent carbon ?ber ?lled. These materials are supplied
`geometric patterns of roughened surfaces on the periph
`from ICI Industries of Wilmington, Del. Carbon-carbon
`eries of the implants enhancing the bone growth. Novel
`?ber plastics of the type sold by Fiber-Rite Corporation
`tools are releasably attached to the end faces of these
`of Winona, Minn., are useful.
`implants.
`The roughened surfaces of the permanent implant
`The present invention now still further improves this
`plugs are non-yielding and have con?gurations to best
`art by providing a group of smooth faced trial or gauge
`grip the 'channels of the vertebral body and to permit
`blocks or plugs of different heights and widths for tem
`bone ingrowth therebetween.
`porary insertion in the rectangular grooves or slots cut
`Preferred embodiments of the invention are illus
`into the adjacent vertebrae to locate a plug that will
`trated in the annexed drawings in which:
`tightly fit the slots and stretch the disc tissue a desired
`FIG. 1 is a side-elevational view of the lower portion
`amount. This procedure permits the surgeon to select a
`of a human vertebrae column with parts broken away
`permanent implant plug with a rough surface of a
`and shown in section to illustrate ?at-sided rectangular
`slightly larger size that can be force ?tted into perma
`prosthetic implant plugs or blocks of this invention
`nent position to further stretch the annulus tissue ?bers
`inserted in rectangular grooves or channels in the op
`of the disc still connecting the vertebrae placing them
`posed faces of adjacent vertebrae to support the verte
`under tension thus facilitating their growth and also
`brae in place of the human disc therebetween which has
`causing the vertebrae to tightly grip the plug. Further,
`been partially excised to remove damaged and herni
`the permanent impact plugs are provided with beveled
`ated tissue.
`or taped leading ends to spread the vertebrae apart and
`FIG. 2 is a posterior elevational view of a
`facilitate insertion into the rectangular channels or slots.
`portion of FIG. 1 taken along the line II—II of FIG.
`Still further, the plugs may have vertical, horizontal, or
`1.
`both horizontal and vertical intersecting slots there
`FIG. 3 is a transverse sectional view, with parts in
`through packed with bone grafts to expedite bone in
`elevation and broken away in section, along the line
`growth. Also, the plugs can be made of radiolucent
`III-III of FIG. 2.
`material to facilitate x-ray inspection of the bone
`FIG. 4 is an enlarged fragmentary side-elevational
`view with parts broken away and shown in vertical
`growth.
`'
`section illustrating the manner in which a trial or gauge
`plug or block of this invention is inserted in position in
`the transverse rectangular slots of adjoining vertebrae
`to stretch the remaining interposed disc tissue con
`nected to these vertebrae and to gauge the sites for
`receiving a proper sized permanent implant.
`FIG. 5 is a plan view of a vertebrae disc with the
`interior pulp removed and with disc tissue partially
`excised to provide gaps or slots aligned with channels
`cut in the vertebrae to receive the plugs therethrough.
`FIG. 6 is a perspective view of a smooth faced trial or
`gauge plug or block for use as shown in FIG. 4.
`FIG. 7 is a perspective view of a preferred form of
`permanent implant plug or block of this invention.
`FIG. 8 is a longitudinal vertical sectional view of the
`plug of FIG. 7 taken along the line VIII—VIII of FIG.
`7.
`
`SUMMARY OF THE INVENTION
`The present invention now provides vertebral pros
`thesis implant plugs or blocks fitting rectangular trans
`verse or perpendicular channels or grooves cut in the
`adjoining faces of vertebral bodies having heights that
`will stretch the remaining annulus tissue of the discs
`45
`therebetween still connecting the vertebrae. According
`to this invention, parallelepiped blocks or plugs are
`provided to fit these transverse rectangular channels or
`slots and have beveled or tapered leading ends easily
`inserted into the open ends of the transverse slots to
`spread the vertebrae apart so that the top and bottom
`faces of each block or plug is tightly bottomed in the
`slot with the stretched disc tissues causing the vertebrae
`to grip the plugs. These plugs are inserted laterally or
`transversely of the vertebral column into the slots while
`mounted on the end of an insertion tool, have rough
`ened surfaces to facilitate the bone ingrowth and also
`have vertical or horizontal slots therethrough or inter
`secting vertical and horizontal slots packed with bone
`graft material, such as strips of bone excised from the
`iliac crest of the pelvis. This implant material provides
`a block of living bone that grows all around and though
`the implant plug into the bone of the vertebrae.
`Also, according to this invention, the blocks or plugs
`instead of being made of an inert metal, such as stainless
`steel, titanium, cobalt-chromium-molybdenum alloys
`and the like, can be made of a radiolucent material, such
`as a plastic of the nylon, polycarbonate, polypropylene,
`
`25
`
`55
`
`60
`
`65
`
`As Shown on the Drawings:
`In FIGS. 1-3, the reference numeral 10 illustrates
`generally the lower portion of a human vertebral col
`umn with adjacent vertebrae supported on prosthetic
`implant blocks or plugs 11 of this invention.
`FIG. 4 shows the manner in which adjacent verte
`brae are spread apart to stretch intervening disc tissue as
`a gauge or trial block of this invention is inserted later
`ally into transverse rectangular slots of adjoining verte
`brae.
`In FIG. 1, the vertebral column 10 shows the ?ve
`lower vertebrae Nos. 1-5. Adjacent vertebrae Nos. 2
`
`

`

`15
`
`30
`
`35
`
`4,834,757
`5
`and 3 and adjacent vertebrae Nos. 3 and 4 are separated
`by and supported on the prosthetic implant blocks or
`plugs 11 of this invention. Vertebrae Nos. 1 and 2 and
`vertebrae Nos. 4 and 5 are illustrated as supported on
`and separated by healthy or undamaged human discs 12
`maintaining a disc space 13 between the adjoining verte
`brae.
`Damaged portions of the natural human discs 12 have
`been excised from the vertebrae Nos. 2 and 3 and Nos.
`3 and 4 with the disc spaces 14 being maintained by the
`implant blocks or plugs 11. It is preferred to retain as
`much as possible of the healthy annulus tissue of the
`discs 12 between the vertebrae so that the remaining
`disc tissue 12a will at least partially surround the im
`plants and will be held under tension by these implants.
`However, some of the remaining disc tissue may have
`to be excised to open up spaces for the implant plugs 11.
`The opposed faces of adjoining vertebrae with dam
`aged discs therebetween have aligned ?at-sided rectan
`gular channels or grooves 15 cut therein transversely of 20
`the axis of column 10 to ?rst snugly receive test blocks
`or plugs of this invention for determining the proper
`sizes for the permanent implants 11. These transverse
`channels 15 are sufficiently wide and deep to span the
`central soft cancellous bone and include the hard cortex
`25
`bone of the adjacent vertebrae. The undamaged human
`disc tissue 12a remaining between the vertebrae is also
`cut or trimmed to receive the implants 11 so that as
`much healthy annulus ?brous tissue as is available will
`surround the implants.
`The preferred ?at-sided rectangular channels 15 have
`blind ends 16 to be abutted by the implants 11.
`As shown in FIGS. 2 and 3, the implants 11 are in the
`form of a pair of side-by-side rectangular (speci?cally
`parallelepiped) plugs inserted endwise into the trans
`verse channels 15. These channels have flat bottoms and
`sidewalls to snugly embrace the top and bottom ends
`and side faces of the rectangular plugs. The soft cancel
`lous bone of the vertebrae is illustrated at 17 in FIG. 3
`and is surrounded by the hard cortex bone 18. The
`channels 15 include portions of this hard cortex bone so
`that the implants 11 span the softer cancellous bone and
`rest on the hard cortex bone 18.
`The channels 15 can be formed by a mortise cutting
`chisel tool and in the event disc tissue 12a blocks the
`paths for the plugs 11, tissue can be trimmed or spread
`apart to open up the paths.
`The implant plugs of blocks 11, as shown in FIGS. 7
`and 8, are rigid, inert, solid, parallelepiped , higher than
`wide and longer than high. They are used in coopera
`tion with trial or gauge blocks, such as 19, shown in
`FIG. 6. These blocks 19 have flat, smooth sides and
`ends with flat top and bottoms 19a, ?at sides 19b, a flat
`front end wall 190, a and a flat back end wall 19d. The
`front wall 190 is beveled to a reduced rectangular nose
`surrounded by ?at-sided tapered walls 19e with
`rounded corners 19f
`,
`The back end wall 19d has an internally threaded
`blind axial hole 19g at the center of the wall.
`The gauge blocks 19, in typical surgical operations,
`will have a length of about 25 mm, a width of about 11
`mm and will vary in height from, say, 13 to 17 mm,
`although it should be understood that these parameters
`may vary greatly and may depend on the size of the
`spinal column of the recipient. The tapers 19e are pref
`erably about 30 degrees. The rounded corners 19f of the
`bevels eliminate sharp corners between the top, bottom
`and sides of the beveled faces.
`
`6
`As shown in FIG. 4, a trial or gauge block 19 is se
`lected for force-?tting into the channels 15 while
`mounted on a tool 20 threaded into the hole 19g. The
`beveled front end 19c of the block will pass through any
`portion of the disc tissue 12a covering the entrance
`mouths of the channels 15 by either cutting holes
`through the remaining tissue or by spreading apart the
`?bers of the disc to accept the gauge blocks 19.
`As shown in FIG. 5, the remaining healthy disc tissue
`12a of a disc 12 between the channel cut vertebrae is
`trimmed to open up slots 21 permitting access of the
`gauge blocks 19 to the channels 15. These slots register
`with the channels 15 and can have open front ends 210
`and blind back ends 21b. It is preferred to remove the
`nucleus pulposus from the damaged disc 12 leaving an
`annulus of ?brous tissue connecting the adjoining verte
`brae and surrounding the inserted blocks.
`A proper ?tting gauge block 19 is selected by trial
`and error insertions into the channel cut vertebrae.
`These blocks are smooth faced and can be removed
`even when tightly ?tted in the channels 15.
`As shown in FIG. 4, a gauge block 19, threaded on
`the end of an insertion tool 20 is selected to have a
`height greater than the free span between the bottoms
`of opposed channels 15. Then, when this block is
`pushed through the open ends of the aligned channels
`15, the beveled nose 19c will engage the bottoms of
`these channels forcing them apart as the block is pushed
`into the channels thereby stretching any disc tissue 12a
`still connecting the vertebrae. The block is pushed
`against the blind ends 16 of the channels and the tension
`on the disc ?bers is determined. When a block 19 of
`suf?cient size to properly load the disc tissue and to ?t
`snugly in the channel, is located, a permanent implant
`plug 11 of a size just slightly greater than the gauge
`block is selected. Such a permanent plug is then
`threaded on the end of a tool 20, the gauge block 19 is
`withdrawn, and the permanent implant 11 on the tool is
`forced into a position in the channels 15.
`A preferred permanent implant block or plug 11 is
`illustrated in FIGS. 7 and 8. This plug has about the
`same flat side dimensions as the selected gauge block,
`but has projected from these ?at top, bottom and side
`walls, a pattern of raised annular nubs 22 providing a
`roughened surface, biting into and gripping the bottoms
`and sidewalls of the rectangular channels 15. These
`nubs are separated by annular grooves 23 and longitudi
`nal channels 230 so that each nub 22 will have a ?at
`vertical back wall 22a, a pair of flat vertical sidewalls
`22b and an inclined front face 22c.
`The plug 11 has the same reduced nose 11a sur
`rounded by the same beveled sidewalls 11b as the nose
`19c and beveled sidewall 19e of the gauge block 19. In
`addition a vertical back wall 110 is the same as the back
`wall 19d and contains the same internally threaded hole
`11d as the back walls 19d and 19g of the gauge block 19.
`Further, the implant plug 11 has a vertical slot 24
`therethrough connecting the tops and bottoms of the
`plug. This vertical slot 24 is rectangular, has a width
`about é the width of the block and a length extending
`close to the front and rear ends of the plug.
`This slot 24 is intersected centrally by a horizontal
`through slot 25. It will be understood that, alternately,
`the block 11 may have only a single horizontal or verti
`cal slot.
`The slots 24 and 25 provide cavities in the block or
`plug 11 which are ?lled with strips of bone implant 26
`preferably harvested from the pelvis bone of the recipi
`
`45
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`60
`
`65
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`

`

`10
`
`4,834,757
`7
`8
`2. A prosthetic device adapted for fusing together
`ent. This bone material housed in the implant plugs 11
`adjoining vertebrae with spaced opposed faces on oppo“
`will soon grow out of the grooves or channels 24 and 25
`site sides of a damaged collapsed vertebrae disc having
`into the radial and longitudinally channels between the
`tissue connecting the adjoining vertebrae bodies, said
`nubs 22 surrounding the plug 11 and will then grow into
`opposed faces of the vertebrae bodies having a pair of
`the bone tissue of the adjoining vertebrae.
`laterally spaced posterior to anterior extending trans
`When the implant plug is pushed into its seated posi
`verse channels cut therein, and said disc tissue having
`tion between the vertebrae, the inclined front faces of
`openings therethrough aligned with the channels,
`the nubs 22 will accommodate the forward moving of
`which comprises a rigid inert plug having a greater
`the plug to the blind ends 16 of the channels 15, but the
`height than the damaged disc space between the bot»
`sharp apexes of the nubs will prevent retraction of the
`toms of the aligned channels for force fit into the chan
`plugs since they will bite into the vertebrae bone.
`nels to stretch the disc tissue to maintain the original
`Therefore, once the plugs are seated in proper position,
`undamaged disc space, and spaced nubs radiating from
`they will not shift from this position.
`said plug for biting into surfaces of the channels and
`It is preferred that the heights of the plugs 11 will be
`having passages therebetween to facilitate ingrowth of
`sufficient to maintain a tension load of about 20 to 30
`bone from the vertebrae bodies bottomed in the chan‘
`pounds on the disc tissue. Such a tension load not only
`nels to fuse the bodies together in fixed relation.
`pulls the vertebrae tightly against the plugs, but also
`3. A surgical prosthetic device adapted for fusing
`accelerates bone ingrowth.
`together adjoining vertebrae bodies which comprises a
`The preferred prosthesis plugs or blocks 11 of this
`parallelepiped inert rigid plug having top, bottom, and
`invention not only facilitate and simplify the surgical
`side walls, a leading end and a trailing end, said leading
`procedure but also accelerate interbody fusion of the
`end having a reduced nose surrounded by bevelled
`vertebrae with the plug. The roughened surfaces pro
`edges diverging to said top, bottom and side walls in
`vided by the nubs thus serve a multiple purpose of an
`spaced relation from each other, each nub having an
`choring into the vertebrae, and providing channels for
`inclined front face and a back wall cooperating there
`bone ingrowth.
`with to de?ne a sharp biting edge at the intersection
`From the above descriptions it will therefore be un-:
`thereof, and an open end slot through said plug between
`said leading and trailing ends communicating with said
`derstood that this invention provides important advan
`tages in the surgical procedures for preventing back
`nubs and adapted to be packed with bone implant mate
`rial.
`pain in patients with damaged intervertebral discs.
`4. The device of claim 3 including a first slot open to
`I claim as my invention:
`the top and bottom walls of the plug and a second slot
`1. A surgical prosthetic device adapted for fusing
`intersecting the first slot open to the side walls of the
`together adjoining vertebrae bodies connected by tissue
`plug.
`of a damaged collapsed disc and having spaced opposed
`5. The device of claim 3, wherein the plug has a
`faces on opposite sides of the disc space therebetween
`length greater than height and a width less than height.
`with transverse channels in said faces including hard
`6. The device of claim 3, wherein the plug is com
`peripheral cortex bone surrounding central cancellous
`posed of radiolucent material.
`bone which comprises a rigid inert parallelpiped plug
`7. The device of claim 1, wherein the channels have
`sized and shaped for snug seating in said channels span
`flat sides and extend in a posterior to anterior direction.
`ning and stretching the disc tissue to maintain a desired
`8. The device of claim 1, wherein the plug has two
`disc space between the adjoining vertebrae bodies with
`slots intersecting each other at the longitudinal axis of
`opposite faces bottomed on at least the cortex bone
`the plug.
`portion of both adjacent bodies, said plug having at least
`9. The device of claim 1, wherein the nubs have front
`one open ended slot therethrough exposed to the bone
`faces sloping in the direction of insertion into the chan
`45
`and adapted to be packed with bone implant material,
`nels and sharp edges at their apices.
`and irregular surfaces on said plug having passages
`10. The device of claim 2, wherein the plug is a paral
`therebetween communicating with said slot and facili
`lelepiped.
`tating ingrowth of bone implant material from the slot
`11. The device of claim 2, wherein the plug is com
`and bone from the vertebrae bodies bottomed thereon
`posed of radiolucent material.
`to fuse said bodies together in ?xed relation.
`it
`* ll
`* *
`
`25
`
`30
`
`55
`
`65
`
`

`

`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`4,834,757
`May 30, 1939
`
`PATENT NO. 1
`DATED
`:
`
`IN_VENTOR(S) :
`
`John W. Brantigan
`
`it is certified that error appears in the above-identified patent and that said Letters Patent
`is hereby corrected as shown below:
`
`Column 1, line 37, after "4,743,256", insert ——and--;
`
`Column 5, line 54, after "19c" delete "a";
`
`Column 7, line 3, delete "longitudinally" and insert
`--longitudinaly——
`
`Claim 3, column 8, line 23, after "side walls" insert ——, said
`trailing end having a longitudinal tool receiving recess, nubs
`radiating from said top, bottom and side walls-—.
`
`Signed and Sealed this
`Twenty-second Day of May, 1990
`
`Arrest:
`
`Arresting O?icer
`
`Commissioner of Patents and Trademarks
`
`HARRY F. MANBECK, JR.
`
`