Comparisons Therapeutic Effects of Different PELD Procedure on LSS.

Inclusion Criteria

• •(1) patients with the diagnosis of degenerative lumbar spinal stenosis (LSS) (central stenosis with or without lateral recess stenosis) on mono or double segments, with the imaging evidence of magnetic resonance images (MRI) and computed tomography (CT); (2) patients presented low back pain, limp and sciatica, and have accepted conservative treatment more than 3 months but failed in symptoms relief; (3) patients agreed to accept TESSYS or the "U" route PELD procedure over other spinal surgeries; (4) patients had lumbar MRI imaging examines in our hospital at pre- and post-operation.