A single-center, prospective cohort trial aims to provide stronger evidence regarding the impact of degenerative spondylolisthesis on the clinical outcome of unilateral biportal endoscopy for lumbar spinal stenosis
Age range: 50-80 years
Diagnosis of LSS affecting 1-2 vertebral levels
Predominant manifestation of neurogenic intermittent claudication, with ineffective conservative treatment for at least 3 months
Presence of lumbar DS of less than grade II and absence of spine instability
Diagnosis of isthmic lumbar spondylolisthesis or lumbar DS of grade ≥II
Evidence of instability at the affected vertebral level (intervertebral angle change > 15° and/or vertebral translation ≥ 4.5 mm in standing flexion-extension radiographs of the lumbar spine)
History of prior surgery at the affected vertebral level
Presence of scoliosis with a Cobb angle >20º