Interlaminar Contralateral Endoscopic Foraminotomy Reduces Postoperative Dysesthesia in Patients With Degenerative Lumbar Deformity: A Multicenter Comparative Cohort Study

Study Design Retrospective-prospective multicenter comparative cohort study. Objectives Postoperative dysesthesia (POD) is a recognized complication of transforaminal endoscopic lumbar surgery, with reported rates up to 21.5%. Degenerative lumbar deformity may amplify this risk through vertebral rotation displacing the dorsal root ganglion into the transforaminal trajectory. This study compares POD rates and functional outcomes between transforaminal endoscopic lumbar foraminotomy (TELF) and interlaminar contralateral endoscopic lumbar foraminotomy (ICELF) in degenerative lumbar deformity, and explores vertebral rotation as a mechanistic basis for approach selection. Methods One hundred patients with degenerative lumbar deformity (Cobb ≥10°) and foraminal stenosis underwent single-level endoscopic foraminotomy across 6 centers in Latin America: a retrospective cohort of 46 patients treated with TELF (2021–2023) and a prospective cohort of 54 patients treated with ICELF (2023–2025). Vertebral rotation was measured by CT using the Aaro-Dahlbornmethod. Primary outcome was POD occurrence; secondary outcomes included VAS, ODI, and modified MacNab criteria at 12 months. Results POD occurred in 8/46 TELF patients (17.4%) versus 1/54 ICELF patients (1.9%; p=0.011, OR=11.16), corresponding to an 89% relative risk reduction (NNT=6.4). Functional outcomes were equivalent at 12 months (MacNab excellent+good: 67.4% vs 70.4%, p=0.376). Within the TELF group, vertebral rotation was significantly higher in POD patients (19.2°±4.7° vs 12.2°±4.3°, p=0.001). ROC analysis identified a 15° threshold (AUC=0.870, sensitivity 88%, specificity 74%). Conclusions ICELF is associated with substantially lower POD rates compared to TELF in degenerative lumbar deformity, with equivalent functional outcomes. Vertebral rotation appears to be a specific, measurable risk modifier for POD in the transforaminal approach, suggesting its role in approach selection.