United States Patent
`Michelson
`
`[19]
`
`[11] Patent Number:
`
`5,772,661
`
`[45] Date of Patent:
`
`Jun. 30, 1998
`
`US005772661A
`
`[54] METHODS AND INSTRUMENTATION FOR
`THE SURGICAL CORRECTION OF HUMAN
`THORACIC AND LUMBAR SPINAL DISEASE
`FROM THE ANTERO-LATERAL ASPECT OF
`THE SPINE
`
`Inventor: Gary Karlin Michelson, 438 Sherman
`Canal, Venice, Calif. 90291
`
`Appl. No.: 394,836
`
`Filed:
`
`Feb. 27, 1995
`
`Related U.S. Application Data
`
`Continuation—in—part of Ser. No. 74,781, Jun. 10, 1993,
`which is a continuation—in—part of Ser. No. 698,674, May 10,
`1991, which is a division of Ser. No. 205,935, Jun. 13, 1988,
`Pat. No. 5,015,247, and a continuation—in—part of Ser. No.
`219,626, Mar. 28, 1994.
`
`Int. Cl.“ ..
`51]
`52] U.S. Cl.
`58] Field of Search
`
`..... .. A6115 17/56
`.. 606/61; 623/17
`.... .. 606/60, 61, 72-79;
`623/16, 17
`
`56]
`
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`
`Primary Ex(m1mer—Michael A. Brown
`Attorney, Agent, or Firm—Lewis Anten, Esq.; Amedeo
`Ferraro, Esq.
`
`[57]
`
`ABSTRACT
`
`An improved method and instrumentation for perfonning
`spinal surgery, including discectomy, interbody fusion and
`rigid internal fixation of the spine, from the lateral aspect of
`the spine is disclosed. The surgical procedure can be per-
`formed through a very small incision. The instrumentation
`of the present invention, all of which is inserted from a
`lateral position into the spine in the preferred embodiment,
`comprises a guide pin, a distractor, an extended outer sleeve,
`an inner sleeve an adjustable drill and an implant driver. The
`distractor of the present invention is driven into the disc for
`spacing apart and realigning the adjacent vertebrae. It further
`functions as an alignment rod for inserting the extended
`outer sleeve which is a hollow tubular member capable of
`maintaining said spacing and alignment of two adjacent
`vertebrae and defines a protected space through which
`subsequent
`instruments which may include, but are not
`limited to, a drill and a diameter reducing inner sleeve may
`be passed, as well as a spinal implant. The remainder of the
`surgical procedure consisting of the removal of spinal mate-
`rial across the disc, fusion, and rigid internal stabilization via
`the implant may all be performed via the closed space within
`the extended outer sleeve.
`
`87 Claims, 14 Drawing Sheets
`
`NUVASIVE 1015
`
`1
`
`

`
`5,772,661
`Page 2
`
`U.S. PATENT DOCUMENTS
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`.
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`.
`
`.
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`
`.
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`
`9/1971
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`
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`3/1995
`3/1995
`6/1995
`7/1995
`2/1996
`2/1996
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`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`Lin et al.
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`Campbell .
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`Long .
`.
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`.
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`.
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`.
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`
`.
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`
`2
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`5,772,661
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`1
`METHODS AND INSTRUMENTATION FOR
`THE SURGICAL CORRECTION OF HUMAN
`THORACIC AND LUMBAR SPINAL DISEASE
`FROM THE ANTERO-LATERAL ASPECT OF
`THE SPINE
`
`RELATED APPLICATIONS
`
`This application is a continuation in part of copending
`U.S. application Scr. No. 08/074,781 filed on Jun. 10, 1993,
`which is a continuatio11 in part of U.S. application Ser. No.
`07/698,674 liled on May 10, 1991 which is a divisional of
`application Ser. No. 07/205,935 filed on Jun. 13, 1988, now
`U.S. Pat. No. 5,015,247 all of which are incorporated herein
`by reference. This application is also a continuation in part
`of copending U.S. application Ser. No. 08/219,626 filed on
`Mar. 28, 1994 which is incorporated herein by reference.
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates generally to instrumentation
`and methods of performing surgical procedures 011 the
`human thoracic and lumbar spine along the lateral aspect of
`the spine and from a true lateral or anterolateral approach,
`and specifically to the surgical correction of thoracic and
`lumbar disc disease and spinal deformities where concomi-
`tant fusion is desired.
`
`2. Description of the Related Art
`As regards the thoracic spine, it may be afflicted with a ,
`variety of ailments, some so severe as to require surgical
`intervention. Adisc herniation may compress the spinal cord
`and/or nerve roots and cause pain, loss of function, and even
`complete paralysis of the legs with loss of bowel and bladder
`control. The correct treatment for such conditions is the
`removal of the offending discal tissue. However, this has
`proven both difficult and quite dangerous. When the discs of
`the thoracic spine are approached posteriorly (from behind)
`the spinal cord is in the way. To approach the same hernia-
`tion anteriorly (from the front) requires the very formidable
`procedure of thoracotomy (cutting open the chest) and
`moving the heart and lungs out of the way.
`Quite recently surgeons l1ave begun performing these
`procedures from a lateral approach to the spine (from the
`side) using fiber optic viewing instruments called thoras-
`copes and numerous small surgical openings through the
`chest wall (portals)
`through wl1icl1 various surgical
`instruments, such as burrs, rongeurs and curettes, may be
`placed to remove these disc herniations while avoiding
`formal thoracotomy. Because the discs are very narrow in
`the thoracic spine and the surgeon is approaching the spine
`laterally, there is very little space in which to work as the
`disc is entered in order to get to the back of the disc space.
`Therefore, the amount of disc removal may be limited. In the
`alternative, the surgeon might remove the pedicle to gain
`access to the spinal canal risking further weakening of the
`already diseased area.
`Sometimes, for a variety of reasons including the removal
`of disc material, the thoracic spine may become unstable
`(too much motion) at any given level. Historically, this has
`been treated by fusion, the joining together permanently of
`the unstable vertebrae via a bridge of bone so as to eliminate
`all motion at that location. Fusions about the thoracic spine
`have been performed either anteriorly or posteriorly, either
`procedure being a rather large surgical undertaking.
`Stability of the spine is required for fusion to occur. For
`this reason, and for the purpose of correcting spinal
`
`2
`deformity, it is often necessary to use hardware to rigidly
`internally fixate (stabilize) the spine. To date,
`the only
`benefit the use of the thorascope has provided i11 this regard
`is to allow the previous thoracotomy incision to be some-
`what smaller.
`
`So to date the following problems remain even utilizing
`the most recent technology as regards the surgical treatment
`of thoracic disc disease:
`
`Firstly, the working space within the disc itself to access
`the herniation which is more posterior is quite limited.
`Secondly, multiple or long incisions through the chest are
`still required.
`Thirdly, when fusion is required a major surgical under-
`taking with its considerable risks is required.
`Fourthly, the installation of hardware affixed to the spine
`still requires a thoracotomy, albeit a smaller one if Visual-
`ization is assisted via the thorascope.
`Fifthly, when, as is often the case, the patient requires all
`three, that is, discectomy (excision, in part or whole, of an
`intervertebral disc), fusion, and the application of hardware
`to the spine, those procedures are performed as serially (one
`after the other) combined surgical procedures with added
`surgical times, complications, morbidities, and mortalities.
`As regards to the human lumbar spine, the treatment of
`discal disease with neural compression has generally been
`from a posterior (from behind) approach. This is sensible as
`the lumbar discs are generally quite large and it is only those
`protrusions occurring posteriorly which compress the neural
`elements which are themselves posterior to the discs. These
`posterior approaches have included both true posterior
`approaches and posterolateral approaches to the discs.
`Further, such approaches have been made via open incisions
`or through percutaneous stab wounds. In the latter case,
`instruments are inserted through the stab wounds and moni-
`tored by the use of radiographic imaging or the use of an
`endoscopic viewing device. While it
`is possible to also
`decompress a posterior disc herniation in the lumbar spine
`from an anterior approach (from the front) doing so requires
`the removal of a very substantial portion or all of the disc
`material ir1 the front and mid portions of the disc thus leaving
`that disc incompetent and that spinal segment generally
`unstable. Therefore, such an anterior approach to the lumbar
`spine has been reserved for those instances where a fusion
`is to be performed in conjunction with, and following such
`a disc removal.
`As regards to fusion, the application of bone or bone like
`substances between bones to induce bony bridging, such
`procedures have been performed outside the vertebral bodies
`and/or between the vertebral bodies. The latter being known
`as an interbody fusion. Such interbody fusions have been
`performed from posterior, posterolateral and anterior. The
`adjective applying specifically to the direction from which
`the bone grafts enter the intervertebral space.
`lnterbody
`fusion from the posterior approach while still in use has been
`associated with significant complications generally related
`to the fact that the delicate dural sac and the spine nerves
`cover the back of the disc space and are thus clearly in harms
`way with such an approach. The posterolateral approach has
`generally been utilized as a compliment to percutaneous
`discectomy and has consisted of pushing tiny fragments of
`morsalized bone down through a tube and into the disc
`space.
`Anterior interbody spinal fusion is performed from a
`straight anterior position as regards the path of entry of the
`fusion material into the intervertebral space. Such an ante-
`rior position is achieved in one of two ways. First, by a
`
`17
`
`

`
`5,772,661
`
`3
`straight anterior approach which requires that the peritoneal
`cavity, which contains the intestines and other organs, be
`punctured twice, once through the front and once through
`the back on the way to the front of the spine; or secondly, by
`starting on the front of the abdomen off to one side and
`dissecting behind the peritoneal cavity on the way to the
`front of the spine. Regardless of which approach to the front
`of the spine is used, and apart from the obvious dangers
`related to the dense anatomy and vital structures in that area,
`there are at least two major problems specific to the anterior
`interbody fusion angle of implant
`insertion itself. First,
`generally at the L4L5 disc, the great iliac vessels bifurcate
`from the inferior Vena cava lie in close apposition to, and,
`covering that disc space making fusion from the front both
`diflicult and dangerous. Secondly, anterior fusions have
`generally been done by filling the disc space with bone or by
`drilling across the disc space and then filling those holes
`with cylindrical implants. As presently practiced, the pre-
`ferred method of filling the disc space consists of placing a
`ring of allograft (bone not from the patient) femur into that
`disc space. An attempt to get good fill of the disc space
`places the sympathetic nerves along the sides of the disc at
`great risk. Alternatively, when the dowel technique is used,
`because of the short path from the front of the vertebrae to
`the back and because of the height of the disc as compared
`to the width of the spine, only a portion of the cylindrical
`implant or implants actually engages the vertebrae,
`thus,
`compromising the support provided to the vertebrae and the
`area of contact provided for the fusion to occur.
`'lhere is therefore, in regard to the lu111bar spine, a need '
`for a new method and means for achieving interbody fusion
`which method avoids the problems associated with all prior
`methods, and which have included, but are not limited to,
`nerve damage when performed posteriorly, or the need to
`mobilize the great vessels when performed anteriorly.
`Further, the size of the implants are limited by the dural sac
`posteriorly, and the width of the spine and the delicate vital
`structures therewith associated anteriorly. An improved
`method and means for interbody fusion should provide for
`optimal fill of the interspace without endangering the asso-
`ciated structures and allow for the optimal area of contact
`between the implant or implants and the vertebrae to be
`fused.
`
`SUMMARY OF THE INVENTION
`
`The present invention is directed to methods and instru-
`mentation for performing surgery on the spine along its
`lateral aspect (side) and generally by a lateral or an antero-
`lateral surgical approach, from a position anterior to the
`transverse processes of adjacent vertebrae of the spine, such
`that the instruments enter the body from an approach that is
`other than posterior and make contact with the spine along
`its lateral aspect. The present invention provides for the
`entire surgical procedure to be performed through a rela-
`tively small incision and may be performed in either the
`thoracic or lumbar spine.
`In the preferred embodiment, the instrumentation of the
`present invention comprises a guide pin, a distractor, an
`extended outer sleeve, an inner sleeve and drill adjustable
`for depth and with a depth limiting means. The distractor of
`the present invention is used for initially distracting (spacing
`apart) and realigning adjacent vertebrae of the spine and also
`functions as an alignment rod for inserting the extended
`outer sleeve. The distractor is placed at the a ected disc
`space between adjacent vertebrae through a small incision in
`the body. For example, for surgery in the thoracic spine, a
`small incision in the chest cavity of the patient is made fror11
`
`4
`a lateral approach to the thoracic spine. For surgery in the
`lumbar spine a small incision may be made in the abdominal
`wall of the patient. The insertion of the distractor may be
`guided by a guide pin previously inserted in the disc space
`and visually monitored for proper orientation and placement
`by the surgeon either indirectly through an image intensifier,
`or directly through a thorascope or by direct vision.
`The extended outer sleeve in the preferred embodiment is
`a hollow mbular member having an extension member that
`is inserted in the disc space and is capable of distracting and
`aligning the two adjacent vertebrae fro111 the lateral aspect of
`the spine. In the preferred embodiment, the extended outer
`sleeve has a pair of prongs for fixedly engaging the two
`adjacent vertebrae and f11rther stabilizing the adjacent ver-
`tebrae. With the distractor in place in the affected disc space,
`the extended outer sleeve is placed over the distractor, and
`the distractor guides and aligns the insertion of the extended
`outer sleeve. As the extended outer sleeve is seated, the
`extension member becomes inserted in the disc space and
`the prongs engage the outside wall of the adjacent vertebrae.
`The distractor is then removed and the extended outer sleeve
`maintains the proper distraction and alignment of the adja-
`cent vertebrae. The remainder of the surgical procedure
`consisting of disc removal, fusion, and rigid internal stabi-
`ization may all be performed via the closed space within the
`extended outer sleeve. Alternatively, a convertible extended
`outer sleeve comprising a hollow tubular member that can
`be dissociated from its insertion end which remains engaged
`o the vertebrae to maintain distraction and alignment, may
`be used where it is desired to have direct visualization and
`access to the surgical site for at least a portion of the surgical
`arocedure.
`
`The drilling o11t and the subsequent removal of a rather
`significant mass of the disc itself may be curative in reliev-
`ing a posterior disc herniation as the mass of tissue pushing
`rom within the disc outward and posteriorly is thus
`removed. Further,
`the distractor in driving the vertebrae
`apart exerts significant tension on the walls of the disc which
`are pulled straight also tending to correct any disc hernia-
`ion. Finally, since the hole drilled across the disc space is
`quite close to the posterior borders of the vertebrae, it makes
`he removal of any persisting posterior disc herniation quite
`simple. With the drill removed and the extended outer sleeve
`cleaned out by irrigation and suction, one can then place the
`endoscope directly down the outer sleeve and into the large
`space created by the removal of the disc, and in the preferred
`method, the adjacent vertebral bone, and then remove any
`remaining fragments of disc using conventional hand held
`instruments such as rongeurs and curettes under endoscopic
`visualization.
`
`When it is desirable to remove posterior disc material,
`then a specialized modification of the extended outer sleeve
`having at its distal end a spine engaging portion comprising
`one anterior extension and posteriorly two prongs one each
`above and below the disc space may be used. Further, such
`an extended outer sleeve may be configured such that the
`great length of the hollow tubular portion of the extended
`outer sleeve is detachable, as by unscrewing, from the distal
`working end such that when uncoupled the distal end may
`remain in place maintaining distraction even after the hole is
`drilled and thus allowing the surgeon to work through that
`remaining portion of the extended outer sleeve and the space
`provided by the drilling to remove the posterior disc material
`under direct vision. For those instances where the surgeon
`has elected to access the spine through a more standard
`incision and is viewing the spine directly, the surgeon is then
`able to continue to operate through the distal spine engaging
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`5,772,661
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`portion of the extended outer sleeve and still maintain the
`distraction and alignment of the vertebrae.
`A spinal
`implant may then be inserted through the
`extended outer sleeve and into the hole in the adjacent
`vertebrae. The extended outer sleeve is removed once the
`spinal implant has been inserted. If the spinal implant being
`inserted has surface projections such as a thread, then an
`inner sleeve is inserted in the extended outer sleeve prior to
`drilling to accommodate the height of the projections or as
`in the case of a thread, the difference between the major and
`minor diameters of the implant.
`To further stabilize the spinal implant, a staple alignment
`rod may be mechanically coupled to the spinal implant prior
`to the removal of the extended outer sleeve. The extended
`outer sleeve is then removed and a staple having spine
`engaging prongs is inserted via the alignment rod and is
`coupled to the spinal implant. Ihe alignment rod is removed
`and replaced with a locking screw to secure the staple to the
`spinal implant.
`While the preferred method utilizing a cylindrical implant
`and involving the removal of some bone from each of the
`adjacent vertebrae in preparation for
`fusion has been
`described,
`it is understood that
`the distractor and sleeve
`could as well be rectangular and the drill supplemented with
`or replaced by a box chisel, or other chisel so as to produce
`a rectangular fusion site or similarly any of a variety of
`shapes. Further, it is understood that the outer sleeve could
`be dimensioned so as to confine the removal of the disc
`material, regardless of the means, to the area between the ,
`adjacent vertebrae rather than providing for the removal of
`the bone as well.
`
`OBJECTS OF THE PRESENT INVENTION
`
`It is an object of the present invention to provide instru-
`mentation for performing surgery on the thoracic spine
`through the chest cavity from a lateral approach to the spine.
`It is another object of the present invention to provide a
`method of performing surgery on the thoracic spine through
`the chest cavity from a lateral approach to the spine that is
`safer, more effective and faster than previously possible.
`It is a further object of the present invention to provide
`instrumentation and method of inserting a spinal implant in
`a hole drilled across the disc space and into two adjacent
`vertebrae of the thoracic spine through the chest cavity from
`a lateral approach to the spine.
`It is another object of the present invention to provide for
`a method and instrumentation for performing a thoracic
`diseectomy, an interbody fusion, and rigid internal fixation
`of the spine through the chest cavity from a lateral approach
`and all as a single integrated procedure.
`It is yet another object of the present invention to provide
`for a method and instrumentation for performing a lumbar
`fusion from the lateral aspect of the spine.
`It is further another object of the present invention to
`provide for a method and instrumentation for performing a
`lumbar fusion and spinal canal decompression from the
`lateral aspect of the spine.
`It is further still another object of the present invention to
`provide for a method and instrumentation for performing a
`lumbar fusion, decompressive diseectomy, and a rigid inter-
`nal fixation of the spine and all as a single integrated surgical
`procedure.
`It is further yet another object of the present invention to
`provide for a method and instrumentation to achieve
`diseectomy, fusion and interbody stabilization of the lumbar
`
`6
`without the need to mobilize the great vessels from the front
`of the vertebral bodies.
`
`These and other objects of the present invention will
`become apparent from a review of the accompanying draw-
`ings and the detailed description of the drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a rear perspective view of a segment of the
`thoracic spine with the guide pin of the present invention
`about to be inserted from a lateral approach to the thoracic
`spine ir1to the disc space between two adjacent vertebrae.
`FIG. 2 is a rear perspective view of a segment of the
`thoracic spine with the guide pin inserted in the disc space
`between two adjacent vertebrae and the distractor of the
`present invention about to be placed over the guide pin.
`FIG. 3 is an enlarged front elevational view of a segment
`of the thoracic spine along line 3 of FIG. 2 having a portion
`of the top vertebrae removed and a portion of the disc
`removed with the guide pin, shown partially in hidden line,
`inserted from a lateral approach to the thoracic spine into the
`disc space.
`FIG. 4 is an enlarged front elevational view of the
`segment of the thoracic spine of FIG. 3 with the guide pin
`and distractor, shown partially in hidden line, inserted from
`a lateral approach to the thoracic spine in the disc space.
`FIG. 5 is an enlarged front elevational view of the
`segment of the thoracic spine of FIG. 3 with the distractor,
`shown partially in hidden line,
`inserted from a lateral
`approach to the thoracic spine and seated in the disc space
`and the guide pin removed.
`FIG. 6 is a rear perspective view of a segment of the
`thoracic spine having a distractor inserted from a lateral
`approach to the thoracic spine and seated in the disc space
`and the extended outer sleeve of the present
`invention
`coupled to a driver cap and about to be placed over the
`distractor.
`FIG. 7 is an enlarged front elevational view of the
`segment of the thoracic spine of FIG. 3 with the distractor
`and the extended outer sleeve inserted from a lateral
`approach to the thoracic spine and seated in the disc space.
`FIG. 7A is side perspective view of the extended outer
`sleeve of the present invention.
`FIG. 8 is a rear perspective view of a portion of the
`thoracic spine with the extended outer sleeve fully seated
`over the distractor inserted from a lateral approach to the
`thoracic spine and seated in the disc space and with the
`driver cap removed.
`FIG. 9 is a front elevational View of a segment of the
`thoracic spine of FIG. 3 with the extended outer sleeve
`inserted from a lateral approach to the thoracic spine and
`seated in the disc space and engaging the adjacent vertebrae
`showing the distractor being removed by a distractor puller.
`FIG. 10 is an enlarged front elevational view of the
`segment of the thoracic spine of FIG. 3 with the extended
`outer sleeve inserted from a lateral approach to the thoracic
`spine and seated in the disc space and engaging the two
`adjacent vertebrae.
`FIG. 11 is a front elevational view of a segment of the
`thoracic spine of FIG. 3 with the inner sleeve of the present
`invention being inserted into the extended outer sleeve.
`FIG. 12 is an enlarged front elevational view of the
`segment of the thoracic spine of FIG. 3 with the inner sleeve,
`shown in partial hidden line, inserted into the extended outer
`sleeve that is inserted from a lateral approach to the thoracic
`spine in the disc space and engages two adjacent vertebrae.
`
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`5,772,661
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`7
`FIG. 13 is a side elevational View of a segment of the
`thoracic spine of FIG. 3 showing the extended outer sleeve
`inserted from a lateral approach to the thoracic spine in the
`disc space and engaging the two adjacent vertebrae with the
`inner sleeve and drill shown in an exploded view and
`partially in hidden line.
`FIG. 14 is a cross sectional View along lines 14—14 of
`FIG. 13 of the drill, inner sleeve and extended outer sleeve.
`FIG. 15 is a cross sectional view along lines 15—15 of
`FIG. 13 of the collar for limiting the drilling depth of the
`drill.
`
`FIG. 16 is an enlarged front elevational view of the
`segment of the thoracic spine of FIG. 3 showing the
`extended outer sleeve inserted from a lateral approach to the
`thoracic spine and seated in the disc space and engaging the
`two adjacent vertebrae,
`the inner sleeve inserted in the
`extended outer sleeve, and the drill passing through the inner
`sleeve to create a hole across the disc space and into the
`adjacent vertebrae.
`FIG. 17 is an enlarged front elevational View of the
`segment of the thoracic spine of FIG. 3 with the extended
`outer sleeve inserted from a lateral approach to the thoracic
`spine and seated in the disc space and engaging the two
`adjacent vertebrae illustrating a hole drilled across the disc
`space and into the adjacent vertebrae.
`FIG. 18 is a front elevational view of the segment of the
`thoracic spine of FIG. 3 showing the extended outer sleeve
`inserted fron1 a lateral approach to the thoracic spine and
`seated in the disc space and engaging the two adjacent
`vertebrae, an implant driver, and a spinal implant about to be
`inserted through the extended outer sleeve and into the hole
`drilled across the disc space and into the adjacent vertebrae.
`FIG. 19 is a front elevational View of the segment of the
`thoracic spine of FIG. 3 showing the extended outer sleeve
`inserted from a lateral approach to the thoracic spine and
`seated in the disc space and engaging the two adjacent
`vertebrae and a spinal implant implanted in the l1ole drilled
`across the disc space and into two adjacent vertebrae.
`FIG. 20 is a front elevational view of the segment of the
`thoracic spine of FIG. 3 showing the extended outer sleeve
`inserted from a lateral approach to the thoracic spine and
`seated in the disc space and engaging the two adjacent
`vertebrae and an extractor cap for removing the extended
`outer sleeve about
`to be coupled to the extended outer
`sleeve.
`
`FIG. 21 is an enlarged partial