Functional recovery after lumbar spinal stenosis surgery: Postural balance and residual urine as objective markers.

Introduction: Although the pathognomonic symptom of patients with lumbar spinal stenosis is impaired walking tolerance, they may also have subclinical impairment of postural balance and urinary retention due to chronic compression of the cauda equina. Research question: To investigate changes in postural balance and residual urine volume in patients with chronic lumbar spinal stenosis treated with decompression and fusion. Material and methods: The current study is a prospective longitudinal observational cohort study. Patients scheduled for decompression and fusion due to LSS with spondylolisthesis ≤ grade I were enrolled. Patient reported outcome measures, Tandem test for balance and post-voiding bladder ultrasound was performed at baseline and at 3, 12 and 24 months postoperatively. Results: Among 100 patients included, 90 % had complete follow up data available. The majority (77 %) were female with a mean age of 70.6 years. 89 % of patients reported symptoms for more than six months prior to surgery. All patient reported outcome measures were significantly improved after surgery. Tandem test scores improved from 20.0 at baseline to 26.6 at three months follow up (p < 0.001) which was sustained at two years. Clinically relevant residual urine volume (≥100 mL) seen in 12 patients pre-operatively was absent at two-year follow-up. Discussion and conclusion: Postural balance and post void residual urine, along with patient reported outcome measures, improved shortly after surgery, and the improvement was sustained two years after surgery. Physicians should consider using these two functional objective measures to evaluate disease severity and treatment effectiveness in patients with lumbar spinal stenosis.