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`Europadisches Patentamt
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`European Patent Office
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`Office européen des brevets
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`(11)
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`EP 0 880 938 A1
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`EUROPEANPATENT APPLICATION
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`(43) Date of publication:
`02.12.1998 Bulletin 1998/49
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`(51) Intcl.*: A61B 17/02, A61F 2/46
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`(21) Application number: 98109238.0
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`(22) Dateoffiling: 20.05.1998
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`(84) Designated Contracting States:
`AT BE CH CY DE DK ESFI FR GB GRIEITLILU
`MC NL PT SE
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`Designated Extension States:
`AL LT LV MK RO SI
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`(30) Priority: 30.05.1997 US 48045 P
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`(71) Applicant: United States Surgical Corporation
`Norwalk, Connecticut 06856 (US)
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`(54)
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`‘Instrumentation for implant insertion
`
`A Surgical retractor instrument includes at least
`(57)
`two elongate membersdisposed in side by side relation.
`Each elongate member has proximal and distal end por-
`tions and defines a longitudinal passagewayfor recep-
`tion of surgical instrumentation. The distal end portion
`of each elongated member is configured for insertion at
`least partially within a space defined between adjacent
`
`(72) Inventors:
`¢ Castro, Salvatore
`Seymour, CT 06483 (US)
`¢ McDonnell, Christopher
`Newtown, CT 06470 (US)
`
`(74) Representative: Marsh, Roy Davidetal
`Hoffmann Eitle,
`Patent- und Rechtsanwéalte,
`Arabellastrasse 4
`
`81925 Munchen (DE)
`
`tissue portions, preferably, adjacent vertebrae. The dis-
`tal end portion includes at least two retractor arms ex-
`tending in a general longitudinal direction. Each retrac-
`tor arm hasfirst and second supporting surfaces for en-
`gaging opposed adjacenttissue portions, and defines a
`dimension between the first and second supporting sur-
`taces sufficient to distract the opposed tissue portions
`uponinsertion thereof.
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`FIG. 8B
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`EP0880938A1
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`Printed by Jouve, 75001 PARIS (FR)
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`Description
`
`BACKGROUND
`
`1. Technical Field
`
`The present disclosure generally relates to a meth-
`od and associated instrumentation for implant insertion
`and, in particular, to a method and instrumentation for
`insertion of a pair of spinal implants to facilitate fusion
`of adjacent vertebral bodies.
`
`2. Background of the Related Art
`
`A large number of orthopedic procedures involve
`the insertion of either natural or prosthetic implants into
`bone or associated tissues. These procedures include,
`for example, ligament repair, joint repair or replacement,
`non-union fractures, facial reconstruction, spinal stabi-
`lization and spinal fusion. In a typical procedure, anin-
`sert, dowel or screw is inserted into a prepared bore
`formedin the bone or tissuesto facilitate repair and heal-
`ing. See, for example, U.S. Patent Nos.: 5,470,334 to
`Rosset al.; 5,454,811 to Huebner; 5,480,403 to Lee et
`al.; 5,358,511 to Gatturna et al.; and 4,877,020 to Vich.
`Some implants are particularly configured with cav-
`ities and boresto facilitate bony ingrowth and enhance
`anchoring of the implant at the insertion site. See, for
`example, U.S. Patent Nos.: 4,328,593 to Sutter et al.;
`4,936,851 to Fox etal.; and 4,878,915 to Brantigan. Oth-
`er specialized implants include fusion cages having in-
`ternal cavities to receive bone growth stimulation mate-
`rials such as bone chips and fragments. See, for exam-
`ple, U.S. Patent Nos.: 4,501,269 to Bagby; 4,961,740 to
`Ray et al.; 5,015,247 to Michelson; and 5,489,307 to
`Kuslich et al. These types of implants are particularly
`well suited for intervertebral spinal fusion procedures
`necessitated by injury, disease or some degenerative
`disorder of the spinal disc. Subsequently, there may be
`progressive degeneration leading to mechanical insta-
`bility between adjacent vertebrae necessitating direct
`fusion of the vertebrae while maintaining a pre-defined
`intervertebral space. This fusion may be accomplished
`by the insertion of one or more of the specialized im-
`plants as discussed above and also discussed U.S. Pat-
`ent No. 5,026,373, the contents of which are incorporat-
`ed herein by reference.
`Both anterior (transabdominal) and posterior surgi-
`cal approaches are used for interbody fusions of the
`lumbar spine. Fusions in the cervical area of the spine
`are primarily performed using posterior and anterior ap-
`proaches as well. Typically, an implant such as a plug,
`dowel, prosthesis or cage is inserted into a preformed
`cavity inside the interbody, interdiscal space. Since it is
`desirable in these procedures to promote a "bone to
`bone"bridge, connective tissue and at least a portion of
`the distal tissue is removed. Preferably, relatively deep
`cuts are made in the adjacent bonesin order to pene-
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`trate into the softer, more vascularized cancellous re-
`gion to facilitate bone growth acrossthe implant.
`One of the morecritical tasks performedin the in-
`sertion of a surgical fusion implant, particularly,
`in in-
`tervertebral spinal fusion, is the formation of the implant
`receiving cavity or bore within the adjacent vertebrae.
`More particularly, the drilled bore must be equally cen-
`tered within the intervertebral space and preferably par-
`allel to the vertebral end plates to ensure removal of
`equal portions of bone from the adjacent vertebrae
`throughoutthe length of the cut and subsequent appro-
`priate seating of the implant relative to the vertebral bod-
`ies.
`
`Surgical instruments for facilitating spinal fusion im-
`plant insertion are known. For example, U.S. Patent No.
`5,484,437 to Michelson discloses a method and appa-
`ratus incorporating an outer and an inner sleeve ar-
`rangement. The outer sleeve has teeth at one end which
`are driven directly into the posterior surface of the adja-
`cent vertebrae. The inner sleeveis positioned within the
`outer sleeve and serves to guide instruments such asa
`drill used to form the implant receiving bore. U.S. Patent
`Nos.: 5,487,307 to Kuslich et al.; 5,015,247 to Michel-
`son; and 4,878,915 to Brantigan disclose similar ar-
`rangements. Other arrangements include the use of
`guide rods which areplacedin pilot holes formed in the
`vertebral bodies. The guide rods guide a bore forming
`hollow drill into the intervertebral space.
`Although current instrumentation and methods as-
`sociated therewith for enhancing the placement of spi-
`nal fusion implants have been generally effective for
`their intended purposes, there exists certain limitations
`with the design of this instrumentation which detract
`from their usefulness. For example, the arrangement
`disclosed in the Michelson '437 patent and similar ar-
`rangements do not provide for automatic alignment of
`the outer sleeve to ensure that the bore formed by a drill
`introduced into the outer sleeve is in optimal alignment
`for a tapping procedure(if required) and reception of the
`spinal implant. Rather, such orientation is dependentdi-
`rectly upon the skill of the surgeon. Moreover, the outer
`sleeve, which is mountedonly atits extreme distal end
`tothe posterior surface of the adjacent vertebrae, is sub-
`ject to disorientation or dislodgment during insertion
`and/or removal of the drill and/or tapping instrument.
`Similarly, the use of guide rods increases the number of
`steps required to implant the fusion cage and is also
`subject to possible misalignment.
`In many surgical implant techniques, two implants
`are inserted within the intervertebral space in side-by-
`side or lateral relation to fully support the adjacent ver-
`tebrae across the span of the intervertebral space.
`In
`accordance with these techniques, a first lateral side of
`the intervertebral space is prepared, e.g., by removing
`excess disc material and drillingAapping a bore to re-
`ceive the implant followed by insertion of the implant.
`Thereafter, the second lateral side is prepared for im-
`plant insertion in the same manner. During the initial
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`preparation of the first lateral side of the intervertebral
`space, however, the adjacent vertebrae are subjected
`to displacement in both the lateral and longitudinal di-
`rection. This may cause additional movementof the ver-
`tebral portion disposed on the other (second) lateral side
`of the intervertebral space.
`U.S. Patent No. 5,489,307 to Kuslich discloses a
`surgical method for implanting two spinal implants into
`a disc space utilizing a distraction spacer which is in-
`serted initially within one side of the intervertebral
`space. The rigid distraction spacer is intended to act
`against the vertebral end plates of the adjacent verte-
`brae to urge the vertebrae apart while the second side
`of the intervertebral space is prepared, by drilling/ap-
`ping, to receive an implant. Once the implantis inserted,
`the distraction spacer is removed and the side left un-
`occupied by removal of the spacer is prepared to receive
`the second implant.
`The present disclosure is directed to a method and
`associated instrumentation to facilitate the introduction
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`of at least two fusion implants, which maintains the de-
`sired disc height across the span of the intervertebral
`space and thereby ensures opiimal alignment of each
`drilled bore for reception of the fusion implant.
`
`SUMMARY
`
`In one preferred embodiment, a surgical retractor
`instrument
`is disclosed. The retractor instrument
`in-
`
`cludes at least two elongated members connected to
`each other in side by side relation. Each elongated
`member has proximal and distal end portions and de-
`ines a longitudinal passagewayfor reception of surgical
`instrumentation. The distal end portion of each elongat-
`ed member is configured for insertion at least partially
`within a space defined between adjacent tissue por-
`ions. Preferably, the distal end portion of each elongat-
`ed member includesat least one retractor arm extend-
`
`
`
`longitudinal direction. Each retractor
`ing in a general
`arm hasfirst and second supporting surfaces for engag-
`ing opposed adjacent tissue portions, and defines a di-
`mension between the first and second supporting sur-
`aces sufficient to distract the opposed tissue portions
`upon insertion thereof. The first and second supporting
`surfaces of each retractor arm may be substantially pla-
`nar. The retractor arms may be dimensioned between
`he first and second supporting surfacesto distract ad-
`jacent vertebrae.
`In an alternate embodiment
`two
`
`spaced apart retractor arms extend from the distal end
`portion of each elongated member.
`In another preferred embodiment, a surgical retrac-
`tor for use in distracting adjacent vertebrae includesfirst
`and second elongate sleeve members connected to
`each other in side by side relation. Each sleeve member
`has a proximal end and a distal end and defines a lon-
`gitudinal passagewaytherebetween. Atleast two retrac-
`tor arms extend longitudinally from the distal end of the
`retractor. Each retractor arm definesa first vertebra sup-
`
`porting surface and a second vertebra supporting sur-
`face portion. The first and second vertebra supporting
`surfaces of each retractor arm are spaced thereon ata
`predetermineddistraction distance.
`In an alternate embodiment, a spacer member is
`disposed between the first and second sleeve members
`to space the sleeve members at a predetermined dis-
`tance.
`
`A method for performing a surgical procedure with
`the surgical retractor is also disclosed. The method in-
`cludes the stepsof providing a surgical retractor includ-
`ing at least two elongate members connected to each
`other along longitudinal portions thereof and having
`proximal and distal end portions with an opening there-
`through to receive instrumentation, the distal end por-
`tion of each elongate member configured for insertion
`at least partially into an intervertebral space between
`adjacent opposed vertebrae, inserting the distal end of
`the two elongate membersof the retractor to distract lat-
`eral sides of the intervertebral space and performing the
`surgical procedure adjacent the distracted vertebrae.
`The distal end portion of at the retractor may include two
`spaced apart retractor arms having first and second
`supporting surfaces and wherein the step of distracting
`includes inserting the retractor arms within the interver-
`tebral space wherebythe first and second supporting
`surfaces of each retractor arm respectively engage the
`adjacent opposed vertebrae. Surgical instrumentation
`may be inserted within the opening of one of the elon-
`gate members to perform the surgical procedure. In a
`preferred embodiment, a fusion implant
`is
`inserted
`through the opening of the one elongate member and
`between the distracted vertebrae to effect fusion there-
`of.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
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`scribed hereinbelow with reference to the drawings
`wherein:
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`illustrates a double surgical retractor con-
`1
`FIG.
`structed in accordance with the principles of the
`present disclosure and utilized in distracting adja-
`cent bony structures, particularly adjacent verte-
`brae, and having first and second retractor sleeves;
`FIG. 2 is a top plan view of the double retractor of
`FIG. 1;
`FIG. 3 is a side plan view of the double retractor,
`FIG. 4 is across-sectional view of the double retrac-
`
`tor taken along the lines 4-4 of FIG. 3;
`FIG. 5 is a perspective view of a surgical kit for per-
`forming a spinal fusion procedureillustrating, from
`bottom to top, the double retractor of FIG. 1, an im-
`plant insertion apparatus, a surgical tap instrument,
`a drill instrument and a T-shaped handle;
`FIG. 6 is a view illustrating a portion of the vertebral
`column;
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`FIG. 7 is a side viewillustrating insertion of the dou-
`ble retractor of FIG. 1 within an intervertebral space
`defined between adjacent vertebrae;
`FIG. 8A is a view of the intervertebral space taken
`along the lines 8A-8A of FIG. 6 illustrating insertion
`of the drill instrument through a first retractor sleeve
`of the double retractor to drill a bore adjacenta first
`lateral side of the adjacent vertebrae;
`FIG. 8B is a view similar to the view of FIG.
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`8Ail-
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`lustrating insertion of the drill instrument within the
`second retractor sleeve to drill a bore adjacent a
`second lateral side of the adjacent vertebrae;
`FIG. 8C is a view taken along the lines 8C-8C of
`FIG. 8B further illustrating advancementof the drill
`instrument within the intervertebral space defined
`between adjacent vertebrae;
`FIG.
`9A is a view similar to the view of FIG.
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`BA il-
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`lustrating insertion of the tap instrument within the
`first retractor sleeve for tapping the bore formedin
`the first lateral side of the adjacent vertebrae by the
`drill instrument;
`FIG. 9B is a view similar to the view of FIG. 9A il-
`
`lustrating insertion of the tap instrument within the
`second retractor sleevefor tapping the bore formed
`in the second lateral side of the adjacent vertebrae
`by the drill instrument;
`FIG. 10 is a view similar to the view of FIG. 8Aillus-
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`trating insertion of the implant insertion instrument
`with mounted fusion implant within the retractor to
`mountthe implant within the tapped bore;
`FIG. 11 is a view taken along the lines 11-11 of FIG.
`10 further illustrating insertion of the implant inser-
`tion instrument within the intervertebral space de-
`fined between adjacentvertebrae;
`FIG. 12 is a cross-sectional view illustrating the in-
`sertion of two implants within the intervertebral
`space;
`FIG. 13 is a perspective view of an alternate em-
`bodiment of the double surgical retractor of FIG.
`1
`having a spacing member interposed between the
`retractor sleevesto laterally displace the two retrac-
`tor sleeves;
`FIG. 141s a top plan view of the couble retractor of
`FIG. 13;
`FIG. 15 is a view of the double retractor of FIG. 13
`
`taken along the lines 15-15 of FIG. 14;
`FIG. 16 is a top plan view of another alternate em-
`bodiment of the double surgical retractor having a
`curved engagementsurface;
`FIG. 17 is a perspective view of yet another alter-
`nate embodiment of the double surgical retractor
`having two retractor arms; and
`FIG. 18 is a top plan view of the double surgical re-
`tractor of FIG. 17.
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`DETAILED DESCRIPTION OF THE PREFERRED
`
`EMBODIMENT(S)
`
`The preferred embodiments of the method and in-
`strumentation disclosed herein are discussed in terms
`
`of orthopedic spinal fusion procedures and instrumen-
`tation. It is also envisioned, however, that the disclosure
`is applicable to a wide variety of procedures including,
`but, not limited to ligament repair, joint repair or replace-
`ment, non-unionfractures, facial reconstruction and spi-
`nal stabilization.
`In addition,
`it
`is believed that the
`present method and instrumentation finds application in
`both open and minimally invasive proceduresincluding
`endoscopic and arthroscopic procedures wherein ac-
`cess to the surgical site is achieved through a cannula
`or small incision.
`
`The following discussion will include a description
`of each instrumentutilized in performing a spinal fusion
`methodfollowed by a description of the preferred meth-
`od for spinal fusion utilizing the instrumentation in ac-
`cordance with the present disclosure.
`In the discussion which follows, the term "proximal",
`as is traditional, will refer to the portion of the structure
`which is closest to the operator, while the term "distal"
`will refer to the portion which is furthest from the oper-
`ator.
`
`Referring now to the drawings in which like refer-
`ence numerals identify similar or identical elements
`throughout the several views, FIG. 1
`illustrates in per-
`spective view a preferred embodimentof the double sur-
`gical retractor of the present disclosure. Double retrac-
`tor 10 is particularly contemplated for distracting adja-
`cent bony structures, é.g., adjacent vertebral bodies, to
`facilitate the insertion and application of a pair of im-
`plants. However,
`it is envisioned that double retractor
`10 may also be utilized to distract other structures as
`well including joints, ligaments, etc... Other applications
`for retractor 10 are also contemplated.
`Referring now to FIGS. 1-2, double retractor 10 in-
`cludesfirst and second retractor sleeves 12a, 12b con-
`nected to each other along adjacentperipheral portions
`as shown. Retractor sleeves 12a, 126 may be formed
`of any suitable rigid material including stainless steel,
`titanium, aluminum ora suitable polymeric material and
`formed by injection molded techniques. Retractor
`sleeves 12a, 12b may be two separate componenis
`connected to each other by conventional meansinclud-
`ing adhesives, welding or the like or may be a single
`monolithic unit.
`
`Each retractor sleeve 12a, 12b is similar in config-
`uration to the retractor sleeve disclosed in U.S. patent
`Application Serial No. 08/615,379, filed March 14, 1996,
`the contents of which are incorporated herein by refer-
`ence. Each sleeve 12a, 12b may be a variety of sizes
`such as 12mm, 14mm, 16 mm and 18 mm in diameter.
`The retractor size utilized will generally correspond to
`the size of the fusion implant to be applied. As shown,
`each retractor sleeve 12a, 12b has a longitudinal pas-
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`depth of penetration of drill shaft 52 and drill bit 56 into
`the adjacent vertebrae. Drill shaft 52 includes a hexag-
`onal-shaped head 62 atits proximal end to mount T-han-
`dle 250.
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`Tap instrument 100is also disclosed in the '379 ap-
`plication. Tap instrument 100 is utilized for forming an
`internal thread within the drilled bore formed bythe drill
`instrument 50. Tap instrument 100 includes elongated
`member 102 having hex head 104 atits proximal end to
`engage T-shaped handle 250. Tap instrument 100 fur-
`ther includes distal tapping threaded portion 106. Distal
`tapping portion 106 includes a plurality of conveyance
`channels (one is shown) 108 extending longitudinally
`through the cutting thread. Each conveyance channel
`108 has a directional componentparallel to the longitu-
`dinal axis and a directional component transverse to the
`longitudinal axis. Each conveyance channel 108 en-
`compasses approximately an arc of about 1/3 the outer
`circumference of the tapping portion 106. Conveyance
`channels 108 are each dimensioned to receive bone
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`collar 16. Each opening 14 preferably extends radially
`or about between 15%-40% the circumference or pe-
`rimeter of sleeve 12a, 12b and longitudinally preferably
`or about 25%the length of sleeve 12a, 12b. Openings
`14 are contemplated to permit the introduction of surgi-
`cal instrumentation if necessary to assist in carrying out
`he fusion procedure.
`Each sleeve 12a, 12b further includesfirst and sec-
`ond diametrically opposed retractor arms 18. Retractor
`arms 18 extend distally from collar 16 in a general lon-
`gitudinal direction and are spaced from each other. Each
`arm 18 has an arcuate outer surface(i.e., defining a ra-
`material deburred by the cutting edges during the tap-
`dius of curvature substantially equivalent to the radius
`ping procedure and to continually transmit the bone ma-
`of curvature of the remaining portion of the sleeve).
`terial proximally through the channel to avoid undesired
`Each retractor arm 18 hasfirst and second supporting
`material build up at the tapping site. In this manner, tap
`surfaces 18a, 18b in general parallel relation to each
`instrument 100 may be used to completely tap the inter-
`other and preferably to the longitudinal axes "a" of each
`nal thread within the bore without interruption of the tap-
`sleeve 12a, 12b. The supporting surfaces 18a, 18b are
`ping procedure.
`preferably substantially planar. The height "h" of each
`Implant insertion instrument 150 is configured for
`arm 18 (i.e., the distance between supporting surfaces
`mounting and inserting fusion implant 200 within the in-
`18a, 18b) corresponds to the height of the space be-
`tervertebral space.
`Insertion instrument 150 includes
`tween adjacentbony structures to be distracted. For ex-
`elongated shaft 152 having hex-head mounting section
`ample, in spinal fusion application, the height "h" of each
`154 at its proximal end and cylindrical collar 156 atits
`arm 18 preferably ranges from about 0.28 to about 0.35
`distal end. Cylindrical collar 156 is dimensioned to be
`inches. Each arm 18 further includes tapered end por-
`received within the cavity of fusion implant 200. A spring
`tions 20 defining a generally V-shaped configuration.
`ball detent mechanism 158is disposed within cylindrical
`End portions 20 facilitate insertion of retractor arms 18
`collar 156 to releasably engage implant 200. Detent
`within the surgical site, ¢.g., within the intervertebral
`space.
`mechanism 158 is preferably spring-biased outwardly
`to engage corresponding structure defined within fusion
`As depicted in FIG. 5, retractor 10 mayfurther in-
`implant 200 such as a recess or aperture formed in an
`clude impactor head 22 whichis correspondingly dimen-
`interior wall thereof. Any type of detent mechanism 158
`sioned to fit over the proximal endsof retractor sleeves
`12a, 12b. Impactor head 22 is dimensionedto slide onto
`suitable for this intended purpose maybe utilized. Collar
`
`retractor 10 and formafrictionfit therebetween. Impac- 156 may further include a pair of longitudinal grooves
`tor head 22 may further include an inner shelf which en-
`160 which engage corresponding structure of implant
`gagesthe proximal end faces of retractor sleeves 12a,
`200 (e.g., inner longitudinal rails) to rotatably fix the im-
`12b. In the alternative, impactor head 22 may be closed
`plant on the collar, i.e., to prevent rotational movement
`at its proximal end.
`of the implant 200 on the collar. Other insertion instru-
`Referring still to FIG. 5, the various instruments uti-
`ments and arrangements are also envisioned.
`lized in performing adouble spinal fusion procedure with
`Implant 200 is uniquely designed for use in spinal
`the retractor 10 of the present disclosure areillustrated.
`fusion procedures. This implant 200 is generally dis-
`These instruments include surgical drill 50, tap instru-
`closedin U.S. Patent No. 5,026,373 to Ray, the contents
`ment 100, implant insertion instrument 150, fusion im-
`of which have been previously incorporated herein by
`plant 200 and T-shaped handle 250 which is used to ac-
`reference, and is commonly referred to as a "fusion
`tuate each of the instruments.
`cage". Implant or fusion cage 200 includesa cylindrical
`cage body 202 having an internal cavity or hole for ac-
`commodating bone-growth inducing substances. One
`end of cage body 202 is closed and defines a rounded
`or bull-nosed configuration to facilitate insertion of the
`fusion cagerelative to one or more bonystructures. The
`
`sageway extending from the proximal to the distal end
`portion to receive surgical instrumentation therethrough
`o carry out the fusion procedure.
`With reference nowto FIGS. 1-4, each sleeve 12a,
`12b mayoptionally include first and second longitudinal-
`ly extending openings 14 formed in its outer wall. Open-
`ings 14 are diametrically arranged with relation to each
`other and terminateat their distal ends in circumferential
`
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`Surgical drill 50 is disclosed in the previously incor-
`porated '379 application. Drill 50 includes drill shaft 52,
`extension shaft 54 and drill bit 56 mounted atthe distal
`end of the drill shaft 52. Extension shaft 54 hasfirst and
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`second collars 58, 60 which cooperate to control the
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`other end defines an opening which communicates with
`the internal cavity. The outer surface of the cage body
`202 includes a single continuous thread (preferably V-
`shaped) having a plurality of raised turns with valleys
`defined between adjacent turns.
`A plurality of perforations are disposed within the
`thread and extend through the outer surface of the cage
`body 202 to provide direct communication between the
`outer surface and internal cavity. The perforations per-
`mit immediate contact between the bone growth induc-
`ing substances within the inner cavity and the bone
`structure when the cage body 202is mated to the bone
`structure, e.g., adjacent vertebrae. An end cap (not
`shown) may be mountable to the open end of cage body
`202 to enclose the bone-growith inducing substances
`within the interior cavity.
`T-shaped handle 250 includes mounting portion
`252 defining hexagonal-shaped recess 254 which re-
`ceives the corresponding structureofdrill instrument 50,
`tap instrument 100 and implant
`insertion instrument
`150.
`
`Operation of the Instrumentation
`
`The use of the instrumentation in conjunction with
`the insertion of a pair of fusion implants 200 into an in-
`tervertebral space defined between adjacent vertebrae
`will be described. The subsequent description will be
`particularly focused on an anterior procedure for spinal
`surgery although a posterior approach is envisioned as
`well.
`
`With reference to FIG. 6, which depicts a portion of
`the vertebral column, a targeted intervertebral space "i"
`defined between adjacent vertebrae "V;, Vo"
`is ac-
`cessed utilizing appropriate retractors, e.g., laminal re-
`tractors, dural extractors.
`As depicted in FIG. 7, impactor head 22 is placed
`on the proximal end of retractor sleeves 12a, 12b. Re-
`tractor 10 is manipulated to align retractor arms 18 with-
`in the desired intervertebral space "i" defined between
`adjacent vertebrae "V,, V.". Preferably, retractor 10 is
`arranged such that retractor sleeve 12a is adjacent a
`first lateral side "S," of the intervertebral space "i" and
`retractor sleeve 12b is adjacent a second lateral side
`"So" of the intervertebral space "i". Thereafter, retractor
`arms 18 are advancedinto the intervertebral space "i"
`wherebyfirst and second supporting surfaces 18a, 18b
`of each retractor arm 18 respectively engage the op-
`posed vertebral bodies "V,, V2". Retractor arms 18 are
`preferably dimensionedto slightly distract the adjacent
`vertebrae "V,, Vo". However, alternatively,
`it
`is envi-
`sioned that retractor arms 18 may be configured to
`cause no distracting movementof the vertebrae "V,,
`Vo". Once inserted, retractor arms 16 effectively stabi-
`lize the adjacent vertebrae "V,, Vo" across the span of
`the intervertebral space "i". Preferably, during insertion,
`retractor 10 is drivendistally, by e.g., impacting impactor
`head 22 with a standard mallet "m" as depicted in FIG.
`
`7, which thereby drives retractor arms 18 within the ad-
`jacent vertebrae "V,, Vo". Tapered end portions 20 of
`retractor arms 18 facilitate advancementwithin the in-
`
`tervertebral space "i".
`Referring now to FIG. 8A, with retractor arms 18 of
`retractor sleeves 12a, 12b in their appropriate positions
`within the intervertebral space "i", attention is directed
`to drilling a bore in the first lateral side "S," of the in-
`tervertebral space "i". The cutting depth of drill instru-
`ment 50 is adjusted as desired(i.e., to correspond to the
`length of the fusion implant) by adjusting collars 58, 60.
`With the T-handle 250 mountedto drill instrument 50,
`the instrumentis introducedinto the axial bore of retrac-
`tor sleeves 12a and advanced to contact the anterior
`
`surface of the vertebral bodies, "V,, V2". Drill 50 is ad-
`vanced into the intervertebral space "i" adjacentthe first
`lateral side "S," by rotating T-handle 250 such thatdrill
`bit 56 shears the soft tissue and cuts the bone of the
`
`adjacent vertebrae "V,, Vo" thereby forming a bore
`which extends into the adjacent vertebrae "V,, Vo". Drill
`50 is then removed from retractor sleeve 12a. The drill-
`
`in-
`ing procedure is then repeated by insertion of drill
`strument 50 within the second retractor sleeve 12b to
`
`form a bore within the adjacent vertebra "V,, Vj" proxi-
`mate the secondlateral side "S," as depicted in FIGS.
`8B-8C.
`
`Referring now to FIG. 9A, tap instrument 100 is se-
`lected and attached to the T-handle 250. Tap instrument
`100 is inserted into first retractor sleeve 12a and posi-
`tioned adjacent the drilled bore formed in the adjacent
`vertebrae "V,, Vp" by the surgical drill 50. With retractor
`sleeve 12a as a direct guide, T-handle 250 is rotated in
`the direction of the directional arrow of FIG. 9A while
`
`simultaneously applying sufficient downward pressure
`on the T-handle to advance the tap instrument 100 and
`promote even purchase into the endplates. Upon ad-
`vancementof the tap instrument 100, the deburred bone
`chips collect within conveyance channel 108 of tapping
`head 106, and are conveyed proximally during rotational
`movementof the tapping head 106 away from the tap-
`ping site. Tap instrument 100 is advanced into the bone
`until the desired depth has been achieved, which occurs
`when the distal end of tapping head 108 "bottoms out"
`on the bone. When tap instrument 100 reachesthe ap-
`propriate depth, the tap instrument 100 is rotated via T-
`handle 250 in an opposite direction to back the instru-
`mentout of the bore. The tapping procedureis then re-
`peated byinsertion of tap instrument 100 within the sec-
`ond retractor sleeve 12b to form a bore within the adja-
`cent vertebrae "V,, Vo" proximate the second lateral
`side as depicted in FIG. 9B. It is to be appreciated that
`in procedures where a self-tapping implantis utilized the
`tapping of the bores with tap instrument 100 is not nec-
`essary.
`With reference now to FIG. 10, attention is focused
`on the insertion of fusion implant 200. FIG. 10 shows a
`first fusion implant 10 already applied within the bore
`proximate the first lateral side "S," of the intervertebral
`
`10
`
`1S
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`
`
`11
`
`EP 0 880 938 A1
`
`12
`
`space i. To apply the fusion implant, cage body 202 of
`the fusion implant 200 is mounted onto insertion instru-
`ment 150 by positioning the cage body 202 onto mount-
`ing collar 156 of the instrument to permit spring ball de-
`tent mechanism 158 to releasably engage correspond-
`ing structure of the implant body 202. This assembly is
`attached to T-handle 250. Insertion instrument 150 with
`
`mounted cage body 202is inserted into retractor sleeve
`12b of retractor 10 and the cage body 202 is positioned
`within the tapped bore by rotating insertion instrument
`150 in the direction depicted in FIG. 10. Cage body 202
`is advanced until it is completely seated with the bore
`as shown in FIG. 11. Insertion instrument 600 is then
`removed from retractor 100.
`
`At this point in the procedure, bone growth inducing
`substances may be harvested from, e.g., the iliac crest,
`and packedinto the cage body 202 of implant 200 until
`the cage body 202 is completely filled with bone growth
`inducing substances. An end cap may then be mounted
`to the cage body 202. Retractor 10 is then removed. It
`is also contemplated that the implant could be at least
`partially packed with bone growth inducing substances
`prior to insertion.
`FIG. 12 illustrates the two lateral fusion implants
`200 inserted within the intervertebral space in accord-
`ance with the afore-described procedure.
`Thus, retractor 10 of the present disclosure main-
`tains a desired spacing between the adjacent vertebra
`"V,, Vo" across the lateral span of