1|||||||||||||ll||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
`
`US 20020165550A1
`
`(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2002/0165550 A1
`Frey et al.
`(43) Pub. Date:
`NOV. 7, 2002
`
`(54) DEVICES AND TECHNIQUES FOR A
`POSTERIOR LATERAL DISC SPACE
`APPROACH
`
`(76) Inventors: George Frey, EngleWood, CO (US);
`John L- White, Bartlett, TN (Us);
`Steven D. DeRidder, Bartlett, TN (US);
`Harald Ebner’ Deggendorf (DE)
`
`Correspondence Address
`Woodard’ Emhardt, Naughten, Moriarty and
`McNett
`Bank One Center/Tower
`Suite 3700
`111 Monument Circle
`Indianapolis, IN 46204-5137 (Us)
`
`(21) Appl, No;
`
`10/120,104
`
`(22) Filed:
`
`Apr. 10, 2002
`
`Related US. Application Data
`
`(63) Continuation-in-part of application No. 09/858,197,
`?led on May 15, 2001, Which is a continuation-in-part
`of application No. 09/694,521, ?led on Oct. 23, 2000.
`
`(60) Provisional application No. 60/160,667, ?led on Oct.
`21’ 1999'
`Publication Classi?cation
`
`(51) Int. c1.7 ................................................... .. A61B 17/16
`(52) US. Cl. .............................................................. .. 606/85
`
`ABSTRACT
`(57)
`This invention relates to devices and instruments for implant
`insertion through a posterior lateral opening to the disc
`space. The instruments include an implant inserter, and the
`devices include a spinal fusion implant engageable by the
`implant inserter. The implant provides bilateral support of
`the adjacent vertebrae When inserted into the disc space from
`a postero-lateral approach.
`
`MSD 1003
`
`1
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 1 0f 49
`
`US 2002/0165550 A1
`
`2
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 2 0f 49
`
`US 2002/0165550 A1
`
`3
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 3 0f 49
`
`US 2002/0165550 A1
`
`4
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 4 0f 49
`
`US 2002/0165550 A1
`
`5
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 5 0f 49
`
`US 2002/0165550 A1
`
`6
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 6 0f 49
`
`US 2002/0165550 A1
`
`7
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 7 0f 49
`
`US 2002/0165550 A1
`
`8
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 8 0f 49
`
`US 2002/0165550 A1
`
`9
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 9 0f 49
`
`US 2002/0165550 A1
`
`10
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 10 0f 49
`
`US 2002/0165550 A1
`
`11
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 11 0f 49
`
`US 2002/0165550 A1
`
`12
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 12 0f 49
`
`US 2002/0165550 A1
`
`13
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 13 0f 49
`
`US 2002/0165550 A1
`
`14
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 14 0f 49
`
`US 2002/0165550 A1
`
`f of
`
`#5
`
`NB
`
`9.:
`
`15
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 15 0f 49
`
`US 2002/0165550 A1
`
`16
`
`

`

`
`
`17
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 17 0f 49
`
`US 2002/0165550 A1
`
`18
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 18 0f 49
`
`US 2002/0165550 A1
`
`260I
`
`ML 6 2
`
`19
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 19 0f 49
`
`US 2002/0165550 A1
`
`274
`
`270
`
`\
`
`274’
`
`270’
`
`\P
`
`m
`
`272’
`
`Fig. 26
`
`35
`4i '
`
`V1
`i )k( ,9
`~1/
`v
`
`37
`
`275’
`
`20
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 20 0f 49
`
`US 2002/0165550 A1
`
`
`
`21
`
`21
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 21 0f 49
`
`US 2002/0165550 A1
`
`
`
`22
`
`22
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 22 0f 49
`
`US 2002/0165550 A1
`
`
`
`23
`
`23
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 23 0f 49
`
`US 2002/0165550 A1
`
`D1
`
`
`
`24
`
`24
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 24 0f 49
`
`US 2002/0165550 A1
`
`
`
`25
`
`25
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 25 0f 49
`
`US 2002/0165550 A1
`
`
`
`26
`
`26
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 26 0f 49
`
`US 2002/0165550 A1
`
`
`
`27
`
`27
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 27 0f 49
`
`US 2002/0165550 A1
`
`
`
`28
`
`28
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 28 0f 49
`
`US 2002/0165550 A1
`
`\v,
`
`t
`
`q"
`’r
`
`650
`
`29
`
`29
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 29 0f 49
`
`US 2002/0165550 A1
`
`
`
`3O
`
`30
`
`

`

`°
`
`°0n
`
`Nov. 7, 2002 Sheet 30 0f 49
`
`US 2002/0165550 A1
`
`302
`
`
`
`31
`
`31
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 31 0f 49
`
`US 2002/0165550 A1
`
`D1
`
`
`
`Fig. 44
`
`32
`
`32
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 32 0f 49
`
`US 2002/0165550 A1
`
`39
`
`342
`
`
`
`Fig. 45
`
`33
`
`33
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 33 0f 49
`
`US 2002/0165550 A1
`
`
`
`34
`
`34
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 34 0f 49
`
`US 2002/0165550 A1
`
`39
`
`v1
`
`35
`
`35
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 35 0f 49
`
`US 2002/0165550 A1
`
`
`
`36
`
`36
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 36 0f 49
`
`US 2002/0165550 A1
`
`
`
`37
`
`37
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 37 0f 49
`
`US 2002/0165550 A1
`
`
`
`38
`
`38
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 38 0f 49
`
`US 2002/0165550 A1
`
`
`
`( I
`
`724’
`
`714’
`
`Fig. 51(3)
`
`39
`
`39
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 39 0f 49
`
`US 2002/0165550 A1
`
`
`
`4O
`
`40
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 40 0f 49
`
`US 2002/0165550 A1
`
`
`
`1202
`
`1200
`
`1100
`
`1108
`
`Wk 1204
`
`41
`
`41
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 41 0f 49
`
`US 2002/0165550 A1
`
`1010
`
`NDCOZ‘Z/
`
`1018b
`
`10147
`
`,
`
`1010
`
`
`
`
`
`42
`
`42
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 42 0f 49
`
`US 2002/0165550 A1
`
`
`
`1034b
`
`1012
`
`43
`
`43
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 43 0f 49
`
`US 2002/0165550 A1
`
`one
`
`22
`
`
`
`
`
`
`
`
`SE
`
`44
`
`44
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 44 0f 49
`
`US 2002/0165550 A1
`
`
`
`
`\J\
`
`1408
`
`1420
`
`45
`
`45
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 45 0f 49
`
`US 2002/0165550 A1
`
`
`
`46
`
`46
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 46 0f 49
`
`US 2002/0165550 A1
`
` 1564,1574
`
`
`
`
`
`47
`
`47
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 47 0f 49
`
`US 2002/0165550 A1
`
`
`
`48
`
`48
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 48 0f 49
`
`US 2002/0165550 A1
`
`
`
`49
`
`49
`
`

`

`Patent Application Publication
`
`Nov. 7, 2002 Sheet 49 0f 49
`
`US 2002/0165550 A1
`
`OWNS
`
`©8—
`
`50
`
`50
`
`
`

`

`US 2002/0165550 A1
`
`Nov. 7, 2002
`
`DEVICES AND TECHNIQUES FOR A POSTERIOR
`LATERAL DISC SPACE APPROACH
`
`SUMMARY OF THE INVENTION
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS:
`
`[0001] The present application is a continuation-in-part of
`patent application Ser. No. 09/858,197 filed May 15, 2001,
`which is a continuation-in-part of US. patent application
`Ser. No. 09/694,521, filed on Oct. 23, 2000, which claims
`the benefit of the filing date of Provisional Application No.
`60/160,667, filed Oct. 21, 1999.
`
`BACKGROUND OF THE INVENTION
`
`[0002] The present invention relates to techniques for use
`in interbody fusion procedures, instruments for performing
`such procedures, and implants insertable in the spinal disc
`space. More specifically, but not exclusively, the present
`invention relates to implants, methods and instruments for
`use in a posterior lateral approach to the disc space, includ-
`ing a transforaminal approach.
`
`[0003] Normally intervertebral discs, which are located
`between endplates of adjacent vertebrae, stabilize the spine
`and distribute forces between the vertebrae and cushion
`
`vertebral bodies. The spinal discs may be displaced or
`damaged due to trauma, disease or aging. A herniated or
`ruptured annulus fibrosis may result in nerve damage, pain,
`numbness, muscle weakness, and even paralysis. Further-
`more, as a result of the normal aging processes, discs
`dehydrate and harden, thereby reducing the disc space height
`and producing instability of the spine and decreased mobil-
`ity. Most typically surgical correction of a collapsed disc
`space includes a discectomy (surgical removal of a portion
`or the entire intervertebral disc). The discectomy is often
`followed by restoration of normal disc space height and
`bony fusion of the adjacent vertebrae to maintain the disc
`space height.
`
`[0004] Access to a damaged disc space may be accom-
`plished from several approaches to the spine. One approach
`is to gain access to the anterior portion of the spine through
`a patient’s abdomen. However, extensive vessel retraction is
`often required and many vertebral levels are not readily
`accessible from this approach. A posterior approach may
`also be utilized. However, this typically requires that both
`sides of the disc space on either side of the spinal cord be
`surgically exposed. This may require a substantial incision
`or multiple access locations, as well as extensive retraction
`of the spinal cord. To alleviate problems associated with
`both anterior and posterior approaches to the spine, a pos-
`terior lateral approach, such as a transforaminal approach, to
`the disc space may be utilized. While it is desirable to place
`one or more implants in the disc space so that the load of the
`spinal column is evenly distributed, accurate placement of
`implants in the disc space from a single posterior lateral
`approach has heretofore been extremely difficult. Thus, this
`approach to the spine is seldom used in practice.
`
`there remains a need for improved
`[0005] Therefore,
`instruments, implants and techniques for use in a posterior
`lateral approach to the disc space that allows unilateral disc
`space preparation and implant insertion to provide bilateral
`stability to the subject disc space.
`
`[0006] The present invention provides implants, instru-
`ments and methods particularly adapted for disc space
`preparation and implant insertion from a posterior lateral
`approach to the disc space.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0007] FIG. 1 is a perspective view of a lamina spreader
`according to the present invention.
`
`[0008] FIG. 2 is a perspective view of the lamina spreader
`of FIG. 1 with the handle portions rotated to a folded
`position.
`
`[0009] FIG. 3 is an elevational view of a spinal column
`segment showing the distal portion of the lamina spreader of
`FIG. 1 engaged to the lamina on either side of a disc space.
`
`[0010] FIG. 4 is a perspective view of a disc space
`spreader according to the present invention.
`
`[0011] FIG. 4(a) is a plan view of the distal end of an
`alternate embodiment disc space spreader.
`
`[0012] FIGS. 5(a) and 5(b) are perspective views of the
`disc space spreader of FIG. 4 with a lever arm and a
`perspective view of the lever arm, respectively.
`
`[0013] FIG. 6 shows the sequence of the insertion of the
`disc space spreader of FIG. 4 into a disc space.
`
`[0014] FIG. 7 is a perspective view of a distractor accord-
`ing to the present invention.
`
`[0015] FIG. 8 is a perspective view of an alternative
`distractor having application in the present invention.
`
`[0016] FIG. 9 is a top plan view of a vertebra with the
`distractor of FIG. 7 inserted in the disc space.
`
`[0017] FIG. 10 is a perspective view of a straight reamer
`according to the present invention having the outer shaft
`partially cut-away to show the inner shaft.
`
`[0018] FIG. 11 is a perspective view of a curved reamer
`according to the present invention having the outer shaft
`partially cut-away to show the inner shaft.
`
`[0019] FIG. 12 is an end view of the reamer cutting head
`used with the reamers of FIGS. 10 and 11.
`
`[0020] FIG. 13 is a top plan view of a vertebra with the
`straight reamer of FIG. 10 inserted in the disc space.
`
`[0021] FIG. 14 is a top plan view of a vertebra with the
`curved reamer of FIG. 11 inserted in the disc space.
`
`[0022] FIG. 15 is a perspective view of a guided rotary
`cutter according to the present invention.
`
`[0023] FIG. 16 is an enlarged view of the distal end
`portion of the cutter of FIG. 15.
`
`[0024] FIG. 17 is a top plan view of a vertebra with the
`cutter of FIG. 15 inserted in the disc space.
`
`[0025] FIG. 18 is a perspective view of a guided rotary
`cutting tool according to the present invention.
`
`[0026] FIG. 19 is an enlarged perspective view of the
`distal end portion of the cutting tool of FIG. 18.
`
`51
`
`51
`
`

`

`US 2002/0165550 A1
`
`Nov. 7, 2002
`
`[0027] FIG. 20 is a top plan view of a vertebra with the
`cutting tool of FIG. 18 in the disc space.
`
`[0028] FIG. 21 is a perspective view of an alternative
`cutting tool head.
`
`[0029] FIG. 22 is a further perspective view of the cutting
`tool head of FIG. 21.
`
`[0030] FIG. 23 is a perspective view of a push scraper
`according to the present invention.
`
`[0031] FIG. 23(a) is section view taken through line
`23(a)-23(a) of FIG. 23.
`
`[0032] FIG. 24 is a perspective view of a pull scraper
`according to the present invention.
`
`[0033] FIG. 24(a) is section view taken through line
`24(a)-24(a) of FIG. 24.
`
`[0034] FIG. 25 is a top plan view of a vertebra with the
`push scraper of FIG. 23.
`
`[0035] FIG. 26 is a top plan view of a vertebra with the
`pull scraper of FIG. 24.
`
`[0036] FIG. 27 is a perspective view of a straight chisel
`according to the present invention.
`
`[0037] FIG. 28 is a lateral elevational view of a spinal
`column segment with the chisel of FIG. 27 inserted in the
`disc space.
`
`[0038] FIG. 29 is a posterior elevational view of a spinal
`column segment showing the disc space entrance created by
`the chisel of FIG. 27.
`
`[0039] FIG. 30 is a perspective view of an alternate
`embodiment guided chisel according to the present inven-
`tion.
`
`[0040] FIG. 31 is an enlarged perspective view of the
`chisel head and shaft with the chisel head in the position of
`FIG. 30.
`
`[0041] FIG. 32 is a top plan view of a vertebra with the
`chisel of FIG. 30.
`
`[0042] FIG. 33 is a perspective view an implant sizing
`guide according to one aspect of the present invention.
`
`[0043] FIG. 34 is the implant sizing guide of FIG. 33 with
`the handle detached.
`
`[0044] FIG. 35 shows a perspective view of an implant
`insertion guide according to the present invention.
`
`[0045] FIG. 35(a) is an enlarged view of the distal end
`portion of the implant insertion guide of FIG. 35.
`
`[0046] FIG. 36 is a perspective view of a straight implant
`inserter according to the present invention having the outer
`shaft partially cut-away to show the inner shaft.
`
`[0047] FIG. 37 is a perspective view of a curved implant
`inserter according to the present invention having the outer
`shaft partially cut-away to show the inner shaft.
`
`[0048] FIG. 38 is a perspective view of an impaction tool
`according to the present invention.
`
`[0049] FIG. 39 is a top plan view of the disc space
`showing the sequence of the curved inserter of FIG. 37
`inserting an implant into the disc space.
`
`[0050] FIG. 40 is a perspective view of an alternate
`embodiment guided implant inserter according to the present
`invention.
`
`[0051] FIG. 41 is an enlarged perspective view of the
`distal portion of the implant inserter of FIG. 40.
`
`[0052] FIG. 42 is an enlarged plan view of the distal
`portion of the implant inserter of FIG. 40 and an implant.
`
`[0053] FIG. 43 is the view of FIG. 42 showing the
`implant and insertion tool moved distally along the guide
`shaft.
`
`[0054] FIG. 44 is a top plan view of a vertebra with the
`implant inserter of FIG. 40 in the disc space.
`
`[0055] FIG. 45 is a top plan view of a vertebra with an
`implant inserted into the distal portion of the disc space.
`
`[0056] FIG. 46 is a top plan view of a vertebra with a pair
`of implants bi-laterally positioned in the disc space to
`provide bi-lateral support to the spinal column segment.
`
`[0057] FIG. 47 is a top plan view of a vertebra with a
`single implant positioned in the disc space to provide
`bi-lateral support to the spinal column segment.
`
`[0058] FIG. 48 is a perspective view of an alternate
`embodiment implant inserter.
`
`[0059] FIG. 49 is a perspective view of a still a further
`embodiment of an implant inserter.
`
`[0060] FIG. 50 is a plan view of an intradiscal rasp
`according to another aspect of the present invention.
`
`[0061] FIG. 50(a) is an enlarged view of an alternate
`embodiment head for the intradiscal rasp of FIG. 50.
`
`[0062] FIG. 51 is a side elevational view of the intradiscal
`rasp of FIG. 50.
`
`[0063] FIG. 51(a) is an elevational view of the head of
`FIG. 50(a) looking in the direction of arrows 51(a)-51(a).
`
`[0064] FIG. 52 is a top plan view of an implant and
`instrument set for inserting the implant into the disc space.
`
`[0065] FIG. 53 is a top plan view of the implant and
`instrument set of FIG. 52 with the implant partially inserted
`in the disc space.
`
`[0066] FIG. 54 is an end elevational view of an implant
`according to another aspect of the present invention.
`
`[0067] FIG. 55 is a top plan view of the implant of FIG.
`54.
`
`[0068] FIG. 56 is a perspective of the implant of FIG. 54
`oriented towards the posterior face.
`
`[0069] FIG. 57 is another perspective view of the implant
`of FIG. 54 oriented towards the anterior face.
`
`[0070] FIG. 58 is an elevational view of the implant of
`FIG. 54 looking towards the posterior face.
`
`[0071] FIG. 59 is a perspective view looking toward the
`posterior wall of another embodiment implant of the present
`invention.
`
`[0072] FIG. 60 is a perspective view looking toward the
`anterior wall of the implant of FIG. 59.
`
`52
`
`52
`
`

`

`US 2002/0165550 A1
`
`Nov. 7, 2002
`
`[0073] FIG. 61 is an elevation view looking at the poste-
`rior wall of the implant of FIG. 59.
`
`[0074] FIG. 62 is an elevation view looking at the anterior
`wall of the implant of FIG. 59.
`
`[0075] FIG. 63 is a plan view of the plant of FIG. 59.
`
`[0076]
`FIG. 59.
`
`FIG. 64 is an end elevation view of the implant of
`
`[0077] FIG. 65 is a sectional plan view of another embodi-
`ment implant insertion instrument according to the present
`invention engaged to the implant of FIG. 59, the sectional
`view illustrating first and second positions of a proximal
`portion of the implant insertion instrument.
`
`[0078]
`ment.
`
`FIG. 65a is a perspective view of a pusher instru-
`
`[0079] FIG. 66 is an enlarged sectional plan view of the
`implant insertion instrument and implant of FIG. 65.
`
`[0080] FIG. 67 is a side elevation view of the implant
`insertion instrument and implant of FIG. 65.
`
`[0081] FIG. 68 is an enlarged plan view of the implant
`insertion instrument and implant of FIG. 65 prior to engag-
`ing the implant to the implant insertion instrument.
`
`[0082] FIG. 69 is an enlarged plan view of the implant
`insertion instrument and implant of FIG. 65 after engage-
`ment of the implant to the implant insertion instrument.
`
`[0083] FIG. 70 is a partial elevation view the proximal
`portion of another embodiment
`inserter instrument and
`alignment instrument.
`
`[0084] FIG. 71 is a section view through line 71-71 of
`FIG. 70 showing the attachment of the alignment instrument
`to the proximal portion of the inserter instrument.
`
`[0085] FIG. 72 is an enlarged section view shown an
`alternate connection arrangement between the proximal por-
`tion and the implant engaging portion of the insertion
`instrument of FIG. 65.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`[0086] For the purposes of promoting an understanding of
`the principles of the present invention, reference will now be
`made to the embodiments illustrated in the drawings, and
`specific language will be used to describe the same. It will
`nevertheless be understood that no limitation of the scope of
`the invention is intended thereby. Any alterations and further
`modification in the described processes, systems, or devices,
`and any further applications of the principles of the inven-
`tion as described herein are contemplated as would normally
`occur to one skilled in the art to which the invention relates.
`
`In a posterior lateral approach to the disc space,
`[0087]
`such as is provided with a transforaminal approach, it is
`often difficult to prepare the proper locations in the disc
`space to receive an implant. The instruments and techniques
`of the present invention provide for improved unilateral disc
`space preparation in both the distal and proximal portions of
`the disc space through a single opening. Another difficulty in
`posterior lateral approaches to the disc space is related to the
`proper positioning of the implant in the portion of the disc
`space most distal from the posterior lateral opening. While
`
`it is desirable that the implant be positioned in the distal
`portion of the disc space, it is often too difficult to move the
`implant across the disc space to the distal portion. Thus, the
`present invention further provides implant inserters, implant
`templates, implant insertion guides, and implants that facili-
`tate implant positioning in the distal and proximal portions
`of the disc from a posterior lateral approach.
`
`[0088] Referring now to FIG. 1, there is provided a lamina
`spreader 500 according to one aspect of the present inven-
`tion. Lamina spreader 500 includes a first arm 502 pivotally
`joined to a second arm 504 by pin 506. Arms 502, 504
`extend generally along a central axis 501 when in a first
`spreading position. Extending distally from pin 506 are
`distal portions 515 and 516 of arms 502 and 504, respec-
`tively. Distal portions 515 and 516 include lamina engaging
`portions 508 and 510, respectively. Lamina engaging por-
`tions 508 and 510 are generally U-shaped and configured to
`engage the lamina of an upper vertebra V2 and the lamina
`of a lower vertebra V1, respectively, on either side of the
`subject disc space, as shown in FIG. 3. Spreading portion
`508 includes an outer portion 508a configured to reside on
`the outer side of the lamina connected to an inner portion
`508b configured to reside on the inner side of the lamina.
`Spreading portion 510 similarly includes an outer portion
`510a configured to reside on the outer side of the lamina
`connected to an inner portion 510b configured to reside on
`the inner side of the lamina.
`
`[0089] The lamina can be spread by the surgeon grasping
`handle 502a of arm 502 and handle 504a of arm 504, and
`forcing arms 502, 504 towards one another in the direction
`towards axis 501. There is also provided a mechanism to
`force and/or maintain spreading portions 508 and 510 apart.
`The spreading mechanism includes an externally threaded
`rod 512 threadingly engaged to branch 502 and a hand nut
`514 received on rod 512. Arms 502 and 504 may be forced
`together by action of threading nut 514 to force rod 512 into
`threaded opening 503 in arm 502, thereby forcing spreading
`portions 508 and 510 apart and separating the lamina to open
`access to the disc space. Nut 514 can also be used to thread
`rod 512 into opening 503 after manually spreading the
`lamina via handles 502a, 504a, until nut 514 contacts arm
`504 to maintain the engaging portions 508, 510 in a spread
`condition.
`
`In a preferred form, arm 502 has handle portion
`[0090]
`502a that is hinged to rotate with respect to a non-rotating
`portion 502b about a pin 516, and arm 504 has handle
`portion 504a hinged to rotate with respect to a non-rotating
`portion 504b about a pin 518. A first spring loaded locking
`mechanism 520 resides in cut-out 524 formed in handle
`
`portion 502a, and a second spring loaded locking mecha-
`nism 522 resides in a similar cut-out (not shown) formed in
`handle portion 504a. Locking mechanism 520 includes a
`finger 528 spring-biased into notch 530 formed in non-
`rotating portion 502b. The surgeon or attendant can release
`handle portion 502a by pulling proximally on grasping
`portion 532 to pull finger 528 out of notch 530, and then
`rotate handle portion 502a transversely to axis 501 about pin
`516 to a position oriented about 90 degrees with respect to
`non-rotating portion 502b. Similarly,
`locking mechanism
`522 includes a finger spring-biased into a notch formed in
`non-rotating portion 504b. The surgeon or attendant can
`release handle portion 504a by pulling proximally on grasp-
`ing portion 534 to pull the finger out of the notch, and then
`
`53
`
`53
`
`

`

`US 2002/0165550 A1
`
`Nov. 7, 2002
`
`rotate handle portion 504a transversely to axis 501 about pin
`518 to a position oriented about 90 degrees with respect to
`non-rotating portion 504b. Rotating handle portions 502a,
`504a moves this portion of lamina spreader out of the way
`of the surgeon and avoids interference with other instru-
`ments to be inserted in the disc space.
`
`It is contemplated that spreader 500 can be used to
`[0091]
`assist the surgeon in gaining access to the disc space. The
`rotating handles allow lamina spreader 500 to remain in
`place during subsequent procedures. It is further contem-
`plated that the surgeon may not desire to use lamina spreader
`500, and therefore proceed with disc space distraction after
`gaining access to the disc space.
`
`[0092] Referring to FIG. 4 and FIGS. 5(a) and 5(b), a disc
`space spreader according to the present invention is shown.
`Disc space spreader 70 has a proximal portion that includes
`a first branch 72 pivotally joined to a second branch 74 by
`pin 76. Extending distally from pin 76 are distal portions 85
`and 86 of branches 72 and 74, respectively. Distal portions
`85 and 86 have a distal working end that includes spreading
`portions 80 and 78 that contact the endplates of the adjacent
`vertebrae to apply a distraction force thereto. Distal portions
`85 and 86 further include lateral offset portions 81 and 79,
`respectively, that laterally offset the branches 72, 74 from the
`spreading portions 80, 78. Offset portions 79 and 81 have a
`straight portion extending generally parallel to central axis
`88 extending between branches 72, 74 and a bend forming
`a first offset angle A2 with axis 88. Spreading portions 78
`and 80 form a second overall offset angle A21 with axis 88.
`In a preferred embodiment, offset angle A2 is about 120
`degrees, but it is contemplated that offset angle A2 can range
`from 90 degrees to 160 degrees. Offset angle A21 is about
`110 degrees. The offset portions 79, 81 laterally offset
`branches 72, 74 from spreading portions 78, 80, allowing
`branches 72, 74 to be further pivoted across the spinous
`process S, as shown by disc space spreader 70 in FIG. 6,
`than would be possible without offset portions 79, 81. In one
`form, the lateral offset distance d between axis 88 and the
`center of the straight portion is between 10 to 20 millimeters.
`This allows the distal tip of spreader 70 to be properly
`oriented into posterior lateral opening 35 formed in disc
`space D1.
`
`[0093] To separate spreading portions 78, 80 a force can
`be applied to the proximal ends of branches 72, 74. In a
`preferred embodiment, disc space spreader 70 includes a
`mechanism to force and/or maintain the separation of
`spreading portions 78 and 80. The spreading mechanism
`includes an externally threaded rod 82 pivotally joined to
`branch 72 and positionable in notch 83 formed in the
`proximal end of branch 74. The spreading mechanism has an
`internally threaded hand nut 84 threadedly received on rod
`82. Branches 72 and 74 may be forced together by action of
`internally threaded nut 84 on branch 74 forcing it towards
`branch 72, thereby forcing spreading portions 78 and 80
`apart. A spring blade 89 attached to branches 72, 74 biases
`branches 72, 74 apart.
`
`[0094] Branches 72 and 74 also define opposing grooves
`92 and 94 adjacent pin 76. A lever arm or pusher 90 may be
`provided having an elongated shaft 96 with a handle 98 on
`one end and an opposing spreader engaging portion 99.
`Engaging portion 99 is configured for removable engage-
`ment with opposing grooves 92 and 94 formed in branches
`
`72 and 74, respectively. In se, removal of bony structures to
`gain access to the disc space and resection of disc material
`may be conducted by known methods. As shown in FIG. 6,
`the distal end of spreader 70 is positioned at opening 35, and
`pusher 90 can be used to provide a pushing force in the
`direction of arrow P into the disc space during the steps of
`inserting the spreading portions 78 and 80 into opening 35.
`Disc space spreader 70 is pivoted sequentially in the direc-
`tion of arrow R about spinous process S via the proximal end
`of branches 72, 74. This pivotal and distal movement from
`proximal portion 41 to distal portion 37 of disc space D1 is
`indicated by the relative sequential positions of spreader 70,
`70', 70", and 70'" and spreader portions 78, 78', 78", and
`78'". Thus, branches 72, 74 and pusher 90 enable the surgeon
`to have simultaneous two-handed control of spreader 70,
`with one hand controlling insertion movement with pusher
`90 and the other hand controlling pivotal movement with
`branches 72, 74. This positions spreading portions 78, 80
`across the disc space, and provides uniform disc space
`distraction so that the vertebral endplates will be parallel
`when distracted. The location of spreading portions 78, 80 in
`the disc space may be checked by any known visualization
`techniques before proceeding to tissue removal.
`
`It should be understood that pusher 90 is engaged
`[0095]
`to disc space spreader 70 during the steps indicated by
`spreaders 70', 70" and 70'", but is not shown for purposes of
`clarity. The S-shaped connecting portions 79, 81 provide a
`lateral offset to branches 72, 74 to laterally offset branches
`72, 74 from spreader portions 78, 80. This allows branches
`72, 74 of disc space spreader 70 to avoid interference with
`the spinous process S when inserting the distal portions
`spreader portions 78, 80 through opening 35 into disc space
`D1. Enlarged stops (not shown) can be formed on distal
`portions 85 and 86 in order to engage the adjacent vertebra
`during insertion and limit advancement of spreaders 78 and
`80 into disc space D1. After the spreader is inserted into the
`disc space, lever arm 90 may be removed.
`
`[0096] Disc space spreader 70 is manipulated as described
`above to spread or distract disc space D1 to the desired
`height. In one procedure,
`it
`is contemplated that lamina
`spreader 500 is first used to spread the lamina. Since this
`tends to tilt the disc space and make the vertebral endplates
`non-parallel, spreader 70 can then be used to distract the
`distal portion of the disc space to provided parallel end-
`plates. Disc space spreader 70 can remain in the disc space
`during subsequent procedures. It is further contemplated that
`lamina spreader 500, pedicle screw fixation with rods or
`plates on the other side of spinous process S may be used to
`maintain the distracted disc space height so that disc space
`spreader 70 can be removed. Distraction shims may also be
`used to maintain disc space distraction, such as disclosed in
`co-pending application entitled METHODS AND INSTRU-
`MENTATION FOR DISTRACTION OF A DISC SPACE,
`filed Oct. 20, 1999, US. patent application Ser. No. 09/421,
`709, which application is incorporated herein by reference in
`it entirety. In another form, lamina spreader 500 is not used
`by the surgeon, and the surgeon only uses disc space
`spreader 70 to restore the normal disc space height.
`
`In FIG. 4(a) there is shown an alternate form for
`[0097]
`the distal portions of disc space spreader 70 which facilitates
`spreader insertion through opening 35. The proximal portion
`of the spreading instrument is similar to spreader 70 dis-
`cussed above and will not be repeated here. Further, specific
`
`54
`
`54
`
`

`

`US 2002/0165550 A1
`
`Nov. 7, 2002
`
`references are made to one alternate distal portion in this
`description, it being understood that the second distal por-
`tion is identical thereto. In addition, a spreader utilizing
`these alternate distal portions can be used in the same
`manner as discussed above with respect
`to disc space
`spreader 70. Central axis 88 between branches 72, 74 is
`provided in FIG. 4(a) to orient distal portions 785, 786 with
`respect thereto. Distal portions 785, 786 each have a distal
`working end that includes spreading portion 778 that con-
`tacts the endplate of the adjacent vertebrae to apply a
`distraction force thereto. Distal portions 785, 786 further
`include branch extension 777 extending from a respective
`one of the branches 72, 74 along axis 88.
`
`inset 779 extends from proximal
`lateral
`[0098] A first
`portion 777 and has a central axis 780 forming an angle A4
`with respect
`to axis 88 such that first
`lateral
`inset 779
`extends in a first direction away from axis 88. Alateral offset
`781 extends from first lateral inset 779 and has a central axis
`
`781 forming an angle A6 with central axis 88 and an angle
`A5 with central axis 780 such that lateral offset 781 extends
`
`in a second direction with respect to axis 88 opposite the first
`direction, positioning the distal end of lateral offset 781 on
`the side of axis 88 opposite first lateral inset 779. A second
`lateral inset 783 extends from lateral offset 781 and has a
`
`central axis 784 forming an angle A5 with central axis 782
`and an angle A4 with central axis 88 such that second l