Comparison of Postoperative Epidural Hematoma Formation Between Biportal Endoscopic Spine Surgery and Conventional Microscopic Surgery: A Randomized Controlled Trial.

Background: Biportal endoscopic spine surgery (BESS) has become widely recognized as a minimally invasive method for spinal decompression and discectomy. However, postoperative epidural hematoma (POEH) presents a significant risk in spinal surgery due to its potential to compress neural elements and lead to neurological deficits. This study compares the clinical and radiological outcomes of BESS with those of conventional microscopic surgery.

Methods: In this single-center, single-blinded, actively controlled randomized clinical trial, 46 patients undergoing single-level posterior decompression or discectomy for spinal stenosis or herniated intervertebral discs were enrolled. Participants were randomly allocated to either the conventional microscopic surgery group or the BESS group. Experienced spine surgeons performed all procedures. Postoperative magnetic resonance imaging assessments were conducted following the removal of the drain system. Outcome measures included the cross-sectional area (CSA) of the dura sac and POEH, as well as the incidence of neurological deficits.

Results: The demographic and baseline characteristics of the patients were similar across the 2 groups, with 24 in the conventional group and 22 in the BESS group. There were no significant differences in the preoperative and postoperative CSA of the dura sac between the groups. However, the BESS group exhibited a significantly larger CSA of POEH (0.36 ± 0.34 cm²) compared with the conventional group (0.17 ± 0.15 cm², P = 0.033). Despite this higher incidence of POEH, there was no corresponding increase in neurological deficits or revision surgeries.

Conclusion: The findings indicate that while BESS achieves decompression comparable to that of conventional microscopic surgery, it is associated with a higher incidence of epidural hematomas. Importantly, these hematomas did not result in an increased rate of neurological deterioration or the need for surgical interventions. Further studies with larger sample sizes and extended follow-up are required to confirm these results and further refine the BESS technique.

Clinical relevance: Despite a higher incidence of epidural hematomas, BESS offers comparable decompression to microscopic surgery without increased neurological risks, making it a viable, less invasive option for patient care.

Level of evidence: 2: