Abstract
ObjectiveThis study was conducted to observe whether patients with more than 50% resection of the inferior articular process (IAP) develop spinal instability.MethodsPatients who underwent unilateral single-segment Interlaminar Endoscopic Lumbar Discectomy (IELD) were reviewed from March 2017 to March 2023 at the authors' institution. Patients with more than 50% resection of the IAP were included. All patients were divided into 2 groups:group T (total resection of IAP), group P (partial resection of IAP). Oswestry Disability Index (ODI) score was used to evaluate low back pain. The following radiographic parameters were measured: (1) slip and disc arc on standing lateral flexion/extension radiographs; (2) intervertebral space height (ISH); and (3) length, width, and thickness of the IAP. (4) width of superior articular process (SAP). The volume of the IAP was estimated by multiplying its height, width and thickness. Patients with Δ slip ≥3 mm or Δ arc ≥15° were classified as having segmental instability. All the parameters were compared with their former values. Correlation coefficients were calculated to evaluate the associations among Δslip, Δarc, ODI, changes in ISH, and other metrics. Multiple linear regression analysis was performed to identify independent predictors of recovery rate after IAP resection. The demographic characteristics of the patients, surgical data, radiographic measurements, and ODI were also compared between the 2 groups.ResultsFifty-one patients were included in the study, and the resection rate of the IAP was 82.01% (62.20%, 93.04%). There was no significant difference in the dynamic arc or slip between preoperative and follow-up (P > 0.05). No case of segmental instability observed at follow-up. The volume of the IAP increased significantly at the final follow-up compared with that immediately after surgery (Z = -5.579, P < 0.001). The recovery rate of IAP was 88.66(22.03,113.91) % with an average time of 16(11,28) months. The follow-up ODI and ISH was 6.5(4.4,11.1) and 7.9(6.5,9.5) mm, respectively. Compared with those before the operation, ODI and ISH decreased significantly (Z = -6.216, P < 0.001; Z = -6.215, P < 0.001). After adjusting for confounding factors, IAP resection rate (β = -0.583, B = -1.821, P < 0.001) and follow-up duration (β = 0.502, B = 0.017, P < 0.001) were the strongest independent predictors of recovery rate, followed by age (β = 0.200, B = 0.010, P = 0.036). No significant independent associations were observed for sex or BMI with IAP recovery rate. At the final follow-up, the volume of the IAP showed no increase in group T, with a significant difference compared with group P (Z = -4.882, P < 0.001). The postoperative ODI score was higher in group T (Z = -2.799, P = 0.005), but there was no significant difference between the 2 groups at the final follow-up.ConclusionIn the cohort of this study, patients with >50% IAP resection did not develop radiographic instability, and some showed bone regeneration, though those with complete resection did not regenerate.