The influence of the positional relationship between the pedicle and the pars interarticularis on unilateral biportal endoscopy: A retrospective cohort study

This study aims to investigate the positional relationship between the pars interarticularis and the pedicle in lumbar spinal stenosis patients and clarify its guiding significance for individualized decompression strategies in unilateral biportal endoscopy (UBE). All patients received standardized UBE. DLM, laminar abduction angle [LAA], laminar width (LW), and facet joint angle (FJA) differed significantly among groups (all P < .001), with smaller DLM associated with narrower LW, smaller LAA, and higher FJA sagittalization. The small DLM group had lower inferior articular process reservation (24.84 ± 16.71%) and higher grade 2 to 3 destruction (75.0%, P < .001), accompanied by worse postoperative back visual analogue scale (VAS), Oswestry Disability Index, longer hospital stay, and greater drainage volume (all P < .05). No significant differences were found in dural sac area improvement or leg VAS among groups (all P > .05). DLM is closely associated with UBE clinical outcomes and an important anatomical reference. Smaller DLM may increase intraoperative facet joint injury risk, potentially due to compact spinal anatomy, which may worsen postoperative recovery. Preoperative DLM evaluation may help identify high-risk patients and guide individualized strategies, balancing decompression efficacy and spinal stability. A retrospective cohort study included patients with L3-S1 lumbar spinal stenosis who underwent UBE decompression between January 2020 and December 2024. Inclusion criteria: confirmed imaging diagnosis, typical symptoms consistent with imaging, ineffective conservative treatment for ≥3 months, limited surgical segments, complete clinical/imaging data, follow-up ≥3 months. Exclusion criteria: lumbar spondylolisthesis (Meyerding grade ≥ II), prior same-segment spinal surgery, pathological stenosis, severe systemic/mental illnesses, blurred imaging data. Patients were grouped by the distance from the lateral margin of pars interarticularis to medial margin of pedicle (DLM). Evaluated indicators: preoperative imaging parameters (LAA, LW, FJA), surgical indicators, clinical outcomes (preoperative/postoperative VAS, preoperative/3-month postoperative Oswestry Disability Index, 3-month postoperative Macnab score), and postoperative imaging parameters (inferior articular process reserved amount, destruction grade, dural sac area). Statistical analyses used SPSS 26.0: ANOVA/Kruskal-Wallis H test, χ2 test/Fisher's exact test, Spearman correlation, Jonckheere-Terpstra test, and ICC for consistency; P < .05 was significant.