Decompression Only by Unilateral Biportal Endoscopic Surgery for Adjacent Segment Degeneration: A Multi-Institution Retrospective Study

Abstract

Objective: Endoscopic surgery is gaining popularity as a minimally invasive option for adjacent segment degeneration (ASD). However, most of the previous literature has focused on transforaminal endoscopic techniques. This study aimed to assess the outcomes of decompressive laminectomy (unilateral laminectomy and bilateral decompression) with unilateral biportal endoscopic (UBE) in patients with lumbar ASD presenting with spinal stenosis. Methods: Thirty-nine ASD patients presenting with spinal stenosis who underwent UBE decompressive surgery between June 2018 and November 2022 at 4 different institutions were enrolled. The postoperative decompression amount and spinal instability were assessed using magnetic resonance images and dynamic radiographs. All patients were followed for at least 1 year, and clinical outcomes were assessed. Results: In the 39 patients, the cross-sectional area of the dural sac (0.55 +/- 0.21 cm2 to 1.11 +/- 0.41 cm2, p<0.001) indicated significant spinal decompression. Dynamic radiographs did not demonstrate significant occurrence of instability in operated segment. Three patients experienced complications, with one case each of hematoma, dural tear, and neurologic deficit. Visual analogue scale scores of the back (6.4 +/- 2.4 to 2.1 +/- 1.2, p<0.001) and leg (7.5 +/- 1.5 to 1.6 +/- 1.6, p<0.001), and Oswestry Disability Index scores (47.5 +/- 16.3 to 19.8 +/- 9.7, p<0.001) indicated significant clinical improvement that was sustained over 1 year. During the average follow-up period of 2 years, 2 patients underwent revision surgery due to failure and relapse. Conclusion: UBE decompressive surgery had satisfactory outcomes in ASD patients, without significant failure or relapse.