Risk Factors and Options of Management for an Incidental Dural Tear in Biportal Endoscopic Spine Surgery

STUDY DESIGN: Here we perform a retrospective analysis regarding an incidental dural tear (IDT) during biportal endoscopic spinal surgery (BESS). PURPOSE: This study investigates the causes of IDT specifically related to technical procedures of BESS with the aim of lowering its risk during training. OVERVIEW OF LITERATURE: The incidence of dural tear is reported 0.5%–18% in open spinal surgery and 1.7%–4.3% during endoscopic spinal surgery. Because conversion to open surgery for direct repair could become necessary during endoscopic spinal surgery, prevention of this complication is essential. METHODS: We have retrospectively studied IDTs by four surgeons during 1 or 2 years after starting BESS for lumbar degenerative diseases and analyzed the locations, sizes, and specific endoscopic conditions specific to each. RESULTS: Twenty-five cases (1.6%) of IDTs among 1,551 cases of BESS occurred; 13 cases (52%) of these were within the first 6 months. The locations were dorsal midline in 12 cases, ipsilateral side in 11 cases, and contralateral side in two cases. The tear sizes were <10 mm in 20 cases and ≥10 mm in five cases. IDT commonly occurred due to injury of central dural folding during flavectomy under turbid surgical fields due to small bleeds under water. Twenty cases with IDTs of <10 mm were treated well with the patch technique. Among five cases of ≥10 mm, three underwent open repair within a few days, and two of these which failed to conservative management required a delayed revision operation due to pseudomeningocele. No cases progressed to surgical site infection or infectious spondylitis. CONCLUSIONS: IDTs of <10 mm can be successfully treated with the patch technique. To prevent IDT during the early learning period, maintaining clear visibility by securing fluent saline outflow and meticulous hemostasis of small bleeding from exposed cancellous bone and epidural vessels is essential with caution not to injure the central dural folding during midline flavectomy.