Comparison of Postoperative Bone Healing in Patients With Unilateral Biportal Endoscopic Lumbar Discectomy and Microscopic Lumbar Discectomy

Objective: Unilateral biportal endoscopic lumbar discectomy and microscopic lumbar discectomy are typical surgical treatments for spinal disease that are performed in different environment. This study investigated differences in bone healing at the postoperative laminecrtomy site between 2 surgical treatments performed in different environments. Methods: From January 2018 to June 2021, 66 patients who underwent laminectomy at Department of Neurosurgery, Gangnam Severance Hospital were retrospectively reviewed. All patients were matched for sex, age, body mass index, bone mineral density, and follow-up duration at a 1:2 matching ratio and were divided into the UBE group (22 patients) and the microscopic discectomy group (44 patients). We investigated the site of laminectomy shown on pre-operative and postoperative x-ray images using ImageJ software. The factors related to bone healing were also investigated. Results: The average bone healing area was 69.59 mm 2 in the UBE group and 44.56 mm 2 in the microscopic discectomy group, constituting a significant difference (p=0.022). The remaining laminectomy area was significantly lower in the UBE group than in the microscopic discectomy group (13.91 mm 2 vs. 53.84 mm 2 , p<0.001). The bone recovery ratio in the UBE group was 85.42%, compared to 51.33% in the microscopic discectomy group, which was a significant difference (p<0.001). The primary laminectomy area, bone healing during 6 months, and clinical outcomes were not significantly different between the 2 groups. Conclusion: Compared with the microscopic discectomy group, the UBE group had a larger bone healing area and a higher bone recovery ratio for patients with lumbar discectomy. These findings suggest that preserving normal structures is more feasible during UBE than during microscopic surgery.