Comparison of clinical efficacy and radiological findings of interspinous dynamic stabilization system versus unilateral biportal endoscopy for lumbar spinal stenosis: a retrospective cohort study.

backgroundPosterior lumbar interbody and fusion (PLIF) for lumbar spinal stenosis (LSS) has declined in recent years, with non-fusion techniques such as the interspinous dynamic stabilization system (IDSS) and unilateral biportal endoscopy (UBE) gaining prominence. However, there remains a paucity of comparative studies directly evaluating the therapeutic efficacy between these two distinct non-fusion approaches-IDSS as a motion-preserving stabilization method and UBE as a minimally invasive decompression technique‌. This investigation seeks to systematically assess and contrast both clinical efficacy and radiological findings associated with IDSS and UBE interventions in LSS management.

methodsThis retrospective cohort study analyzed 209 patients with LSS treated between January 2015 and January 2022, stratified into two cohorts: the IDSS group (n = 112) and the UBE group (n = 97). Demographic and perioperative parameters, including age, gender, body mass index (BMI), hospital stay, operative time, intraoperative fluoroscopy frequency, blood loss, incision length and postoperative complications, were systematically documented for comparative analysis‌. Clinical outcomes were evaluated using the Visual Analogue Scale (VAS) for low back and leg pain and the Oswestry Disability Index (ODI) at four intervals: Preoperative, 1-month postoperative, 3-month postoperative, and the final follow-up. Therapeutic efficacy was further quantified at the final follow-up utilizing the modified MacNab criteria. Radiographic findings compared preoperative and final follow-up measurements across four parameters: segmental range of motion (SROM), intervertebral space height (ISH), facet joint preservation rate (FJPR) and dural sac cross-sectional surface area expansion rate (DSCAER).

resultsBaseline characteristics including age, sex, BMI, surgical levels, and intraoperative fluoroscopy frequency showed no statistically significant differences between groups (P > 0.05). Regarding clinical outcomes, the UBE group demonstrated superior performance than the IDSS group, including operative duration (61.10 ± 10.39 vs. 70.59 ± 11.21 min), estimated blood loss (32.06 ± 10.11 vs. 52.94 ± 12.85 ml), incision length (1.85 ± 0.26 vs. 5.68 ± 0.69 cm), hospital stay (4.17 ± 0.93 vs. 5.82 ± 1.16 days), and complication rates (18.75% vs. 9.28%) (all P < 0.05). Both groups exhibited significant postoperative improvements in low back pain VAS, leg pain VAS, and ODI scores at 1-month, 3-month, and final follow-up intervals compared to preoperative baselines (P < 0.05). Intergroup comparisons of these functional outcomes revealed no significant differences across all timepoints (P > 0.05). Modified MacNab criteria showed comparable excellent/good rates between cohorts (IDSS: 84.82% vs. UBE: 89.69%, P > 0.05). ‌Radiographic findings:‌ At final follow-up, the UBE group maintained preoperative SROM in the operated segments (P > 0.05), whereas the IDSS group showed significant SROM restriction (ΔSROM=-2.09 ± 0.91º, P < 0.05). No significant differences were observed in ISH, FJPR, and DSCAER between the two groups postoperatively compared to preoperative values, or in intergroup comparisons (P > 0.05).

conclusionBoth IDSS and UBE can effectively alleviate pain and improve quality of life in patients with LSS, achieving satisfactory clinical outcomes. Compared to IDSS, UBE is associated with minimized tissue trauma, fewer surgical complications and better preservation of SROM. These advantages position UBE as the preferentially recommended surgical approach for LSS.