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.