Radiographic and Clinical Outcomes Following Unilateral or Bilateral Posterior Fixation in MI-TLIF

Patient must be between 18 and 80 years old and have problems with the bones in there lower
back (lumbar disease) for which Cautious management over at least 3 months has not brought
relief from back and/or leg pain. Patients will be scheduled to undergo surgery to treat
there lumbar disease. The surgery will be followed by placement of screws in the back of the
bones of there lower back. This includes placing solid metal rods that are connected and
secured to adjacent vertebrae (bones of the back) using screws. The screws are used to hold
the spine together. Everyone who takes part in this study will be assigned to one of the
following 3 study groups: 1) One-sided screw placement into the bones above and below the
area where the nerve is being surgically relieved of its pinching; 2) Same as group 1 but
with an additional stand alone screw which crosses the spinal joint placed into the joint on
the other side; 3) Screw placement on both sides into the bones above and below the area
where the nerve is being surgically relieved of its pinching.

Inclusion Criteria:

- Age 18-80 years.

- Symptomatic single-level lumbar disease including lumbosacral junction.

- Unilateral leg-dominant pain non-responsive to conservative management with concordant
imaging findings. These include degenerative spondylolisthesis (grade 1 or 2), facet
arthropathy +/- lateral disc herniation, recurrent disc herniation, or large central
disc herniation.

- Back pain of confirmed discogenic origin (single level disease only).

- Failed conservative management for a minimum of 3 months.

- Negative serum pregnancy test (for women of childbearing potential)

Exclusion Criteria:

- Severe bilateral leg symptoms.

- Prior instrumented arthrodesis at any lumbar level.

- History of osteoporosis.

- Co-morbidities requiring medication that may interfere with bone or soft tissue
healing (i.e., oral or parenteral glucocorticoids, immunosuppressive agent,
methotrexate).

- Severe co-morbidities (e.g., heart, respiratory, or renal disease).

- Recent (<3 yrs) Co-incident spinal tumor or infection.

- Greater than single level symptomatic involvement.

- Associated thoracolumbar kyphotic or scoliotic deformity (>10).

- Morbid obesity (BMI > 40).

- History of metal sensitivity/foreign body sensitivity.

- Concurrent involvement in another investigational drug or device study that could
confound study data.

- History of substance abuse (recreational drugs, prescription drugs, or alcohol) that
could interfere with protocol assessments and/or with the subject's ability to
complete the protocol required follow-up.

- Subjects who are pregnant or plan to become pregnant in the next 24 months.

- Prisoner.