Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
2001-01-05
2003-02-25
Philogene, Pedro (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
C606S080000, C623S017110
Reexamination Certificate
active
06524312
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to spinal fixation and fusion systems. An embodiment of the present invention relates to an insertion guide used during the insertion of a spinal implant into a disc space between a pair of vertebrae. The implant may be used for correction, fixation, and/or stabilization of a spinal column.
2. Description of the Related Art
An intervertebral disc that becomes degenerated may have to be partially or fully removed from a spinal column. Intervertebral discs may become degenerated due to various causes such as trauma, disease, or aging. Removal or partial removal of an intervertebral disc may destabilize the spinal column. A spinal implant may be inserted into a disc space created by the removal or partial removal of an intervertebral disc. The spinal implant may maintain the height of the spine and restore stability to the spine. Bone may grow from adjacent vertebrae into the spinal implant. The bone growth may fuse the adjacent vertebrae together.
A spinal implant may be inserted using an anterior, posterior or lateral spinal approach. An anterior spinal approach may require less bone removal and muscle distraction than a posterior spinal approach. Also, an anterior spinal approach may involve less risk of nerve damage than a posterior spinal approach. Intervertebral disc location or other factors may contraindicate an anterior spinal approach.
During an anterior spinal approach, a surgical opening may be made in the abdomen of a patient. The opening may be 25 centimeters (10 inches) or more in depth for some patients. The opening needs to be large enough and deep enough to accommodate instrumentation that inserts a spinal implant within a disc space. A discectomy may be performed to remove portions of a defective or damaged intervertebral disc and create the disc space. The amount of removed disc material may be determined by the size and type of implant that will replace the removed disc material.
The implants may be constructed of any biocompatible materials sufficiently strong to maintain spinal distraction including, but not limited to, bone, metals, ceramics and/or polymers. Implants may be packed with bone graft or a synthetic bone graft substitute to facilitate spinal fusion. Implants may have a variety of shapes, which include, but are not limited to, threaded cylinders, unthreaded cylinders, and parallelepipeds.
A protective sleeve may be used during preparation and insertion of a spinal implant. The protective sleeve may serve to protect abdominal organs, blood vessels and other tissue during a spinal implant procedure using an anterior approach. The sleeve typically extends above the surgical opening during use. The sleeve may maintain distraction of the vertebrae. Also, the sleeve may serve as an alignment guide for tool and implant insertion during the surgical procedure. Protective sleeves may also be used during a spinal fusion procedure using a posterior or lateral approach.
Protective sleeves typically have distractors on a distal end. Distractors are projections that may be inserted into a disc space during a spinal fusion procedure. The distractors may serve to achieve and maintain distraction of adjacent vertebrae. Distractors may also help to secure the protective sleeve to the vertebrae during the procedure. Protective sleeves may have one tube or two parallel tubes.
FIG. 1
shows a single-tube protective sleeve, and
FIG. 2
shows a dual-tube protective sleeve.
FIG. 1
illustrates a single-tube protective sleeve
30
that may be used in a spinal fusion procedure. A spinal fusion procedure may involve the insertion of one or more implants in a disc space between two vertebrae. Protective sleeve
30
may include a long, hollow tube
32
; two distractors
34
on opposite sides of an end of the tube; and two spikes
36
(only one shown) on opposite sides of the end of the tube. Protective sleeve
30
is typically sufficiently long to allow access to a disc space of a large patient during an anterior procedure. Protective sleeve
30
may also be used in a posterior spinal fusion procedure.
A spinal fusion procedure may involve the insertion of two implants in an intervertebral disc space. A discectomy may be performed to provide space for an initial distractor. The initial distractor may be inserted into the disc space. The initial distractor may be rotated to establish an initial separation distance between a pair of vertebrae that are to be fused together. The initial separation distance may be large enough to allow a width of the protective sleeve distractors
34
to fit between the vertebrae. More disc material may be removed adjacent to the initial distractor to accommodate insertion of the protective sleeve distractors
34
. A protective sleeve
30
may be placed over the initial distractor. A cap (not shown) may be placed on end
38
of the protective sleeve
30
opposite distractors
34
to protect the end of the sleeve during insertion. Distractors
34
may then be hammered into the disc space by striking the cap with a mallet (not shown). Spikes
36
may be hammered into vertebral bone to stabilize protective sleeve
30
during the implant insertion procedure. Distractors
34
may serve to separate the adjoining vertebrae to a desired separation distance. The cap and initial distractor may be removed from the protective sleeve
After insertion of a protective sleeve, a hole may be drilled in the intervertebral disc by inserting a tool with a reaming head attachment through tube
32
and rotating the tool until a predetermined depth is reached. The reaming tool may also remove portions of the end plates of the adjacent vertebrae. In some procedures, the hole is then tapped by inserting a tool with a tap head attachment into tube
32
. The tapping tool may be rotated and driven downward until a predetermined depth is reached. After the hole is prepared, an implant may be inserted in the hole by attaching the implant to an implant insertion tool and inserting the implant into the disc space through tube
32
. For untapped holes, the implant may be hammered into the hole by striking the implant insertion tool with a mallet. For tapped holes, the implant may be threaded into the hole by rotating the implant insertion tool. The implant insertion tool and the protective sleeve may be removed from the patient.
If a second implant is to be inserted, an initial distractor and cap may be utilized during insertion of the sleeve into the disc space adjacent to the first implant. A hole may be prepared and the second implant may be inserted into the disc space. Alternatively, the protective sleeve
30
may remain inserted in the disc space, and a second single-tube protective sleeve
30
may be inserted adjacent to the protective sleeve. A hole may be prepared and the second implant may be inserted into the disc space through the second sleeve.
The optimal alignment and spacing of implants in a spinal fusion procedure may be determined before surgery. Achieving the predetermined alignment and spacing during surgery may be important to achieve optimal fusing of the adjacent vertebrae. Protective sleeve
30
has characteristics that may make achieving alignment difficult. First, each of the two holes is aligned, reamed, and tapped in a separate procedure. It is often difficult to align and space the holes correctly. Second, the alignment of protective sleeve
30
must be maintained after insertion. Any slight movement of protective sleeve
30
, which may act like a lever arm, may result in misalignment of the hole.
FIG. 2
illustrates a dual-tube protective sleeve
40
used in a spinal fusion procedure involving the insertion of two implants into a disc space between a pair of vertebrae. A dual-tube protective sleeve
40
may include long, hollow tubes
32
; one or more distractors
34
; and one or more spikes
36
. Protective sleeve
40
is typically long enough to allow access to an intervertebral disc in a large patient during an anterior procedure. Spinal fusion using
Hochschuler Stephen H.
Krueger David J.
Landry Michael E.
Wagner Erik J.
Meyertons Eric B.
Meyertons Hood Kivlin Kowert & Goetzel P.C.
Philogene Pedro
Spinal Concepts Inc.
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