Impact of postoperative cauda equina clumping on recovery after biportal endoscopic decompression for severe lumbar stenosis.

Abstract

Purpose: This study determined the prevalence of cauda equina clumping among patients with Schizas grade C or higher central stenosis after decompression and compared the radiographic and clinical outcomes between patients with and without clumping.

Methods: We conducted a single-center retrospective cohort study involving 98 patients who underwent biportal endoscopic spine surgery between January 2019 and June 2022. Based on postoperative magnetic resonance imaging findings, the patients were divided into the clumping (n = 40) and non-clumping (n = 58) groups. Clinical outcomes were assessed using the visual analog scale for back and leg pain, Oswestry Disability Index (ODI), and EuroQol 5-Dimension (EQ-5D-5 L) questionnaire at 1, 3, 6, and 12 months postoperatively. Radiographic evaluations included measuring the cross-sectional area of the dural sac preoperatively and 1 month postoperatively using the PACS software.

Results: Postoperative cauda equina clumping was observed in 40.8% of the patients. Despite an average dural sac expansion of approximately 270%, the clumping group exhibited significantly higher radiating pain at 3 and 6 months (p < 0.05) than the non-clumping group. The ODI and EQ-5D scores were worse in the clumping group at 3 months (p < 0.05). At 12 months postoperatively, differences in clinical outcomes between the two groups were not significant. Patients in the clumping group required longer duration of postoperative medication than those in the non-clumping group (p = 0.024).

Conclusion: Post-decompression cauda equina clumping is commonly observed in patients with severe lumbar stenosis and impacts intermediate-term clinical recovery. Although long-term outcomes at 1 year are similar, tailored postoperative care is essential for patients exhibiting clumping to effectively manage prolonged symptoms.