XLIF® vs. MAS®TLIF for the Treatment of Symptomatic Lumbar Degenerative Spondylolisthesis With or Without Central Stenosis.

The purpose of this study is to determine differences in the XLIF and TLIF procedures with respect to perioperative variables in adult patients with low-grade symptomatic spondylolisthesis.

The study is a prospective multi-center randomized evaluation of clinical and radiographic outcomes of two commonly used lumbar interbody fusion procedures (XLIF and TLIF) in adult patients with low-grade symptomatic spondylolisthesis. The study seeks to identify differences between the procedures with respect to perioperative variables.

Study population will consist of patients from participating site locations.

• XLIF
  This group will have the XLIF procedure done.
• MAS TLIF
  This group will have the MAS TLIF procedure done.

Inclusion Criteria:

- Male and female patients who are at least 18 years of age;

- Patients who present with symptomatic Grade I or II degenerative spondylolisthesis at 1 or 2 contiguous lumbar levels between L1 and L5 and are surgical candidates for interbody lumbar fusion surgery; symptoms should include radiculopathy and/or neurogenic claudication with or without back pain;

- Patients who have been unresponsive to at least 6 months of conservative treatments or exhibit progressive neurological symptoms in the face of conservative treatment;

- Patients who understand the conditions of enrollment and are willing to sign an informed consent to participate in the study.

Exclusion Criteria:

- Patients with lumbar pathologies requiring treatment at more than 2 levels;

- Patients who have had previous lumbar fusion surgery;

- Patients with lytic spondylolisthesis or a defect of the pars interarticularis;

- Patients with radiographic confirmation of Grade IV facet joint disease or degeneration;

- Patients with non-contained or extruded herniated nucleus pulposus