Unilateral biportal endoscopic surgical decompression for symptomatic ossification of the ligamentum flavum - Is it enough to improve the clinical outcome? A case-control study.

Purpose: Open decompression is currently the standard surgical procedure for symptomatic OLF. As the minimal invasive method gains popularity, UBE is considered a reliable technique with less complication. However, the outcome is still in question. This study aimed to evaluate and compare UBE versus open surgery in symptomatic OLF cases. Methods: We evaluated 35 patients with single- or two-level thoracic OLF, underwent decompression by open or UBE. Surgery duration, estimated blood loss, and LOS were recorded as intraoperative parameters. Minimum follow-up was 1 year to evaluate clinical parameters based on the mJOA score, Frankel grade, and recovery rate (RR). Results: The UBE procedure showed significant superiority with faster surgery (62.5 min vs. 180 min; p < 0.001), less blood loss (50 mL vs. 250 mL; p < 0.001), and shorter LOS (4 days vs. 6 days; p < 0,001). UBE patients showed notable clinical improvement on the mJOA score at 1 year (8.2 ± 0.18 vs. 6.8 ± 0.24; p = 0.015). Frankel grade improvements seen in both groups with 51.4% of subjects having at least a 1-point upgrade. RR in 1 year resulted in significant recovery in UBE group (RR-UBE 43.2 ± 17 vs. RR-open 26.3 ± 15.3; p < 0.05). No neurological deterioration or significant complication occurred after either procedure. Conclusion: The UBE technique allows faster decompression with less blood loss and shorter LOS compared to open surgery. It was found to be a reliable treatment option in treating OLF with favorable clinical outcomes and improved patient neurological status.