Incidental Durotomy During Endoscopic Stenosis Lumbar Decompression: Incidence, Classification, and Proposed Management Strategies

We sought to review the types of incidental durotomies (IDs) that occurred during the endoscopic stenosis lumbar decompression through interlaminar approach (ESLD) and discuss the management strategies according to our classification. A retrospective evaluation was performed for patients with spinal stenosis who underwent ESLD. Out of 330 patients, 27 patients of ID were clinically evaluated preoperatively and postoperatively on the basis of a visual analog scale score, Oswestry Disability Index, and MacNab's criteria. ID patterns are classified according to the size, location, and involvement of neural elements. Intraoperative and postoperative surgical management was evaluated. Intraoperative incidence of ID was 8.2%. According to lumbar levels, 11 (40.7%) occurred at L3-4, 12 (44.4%) at L4-5, and 4 (14.8%) at L5-S1 ID cases. IDs were divided into 4 types: 29.6% are type 1, 70% are type 2, 7.4% are type 3, and 3.7% are type 4. Overall for mean and standard deviation preoperative, 1 week postoperative, 3 months, and final follow-up for visual analog scale are 7.6 ± 1.4, 3.3 ± 1.1, 2.6 ± 1.1, and 1.9 ± 1.3, and for Oswestry Disability Index are 74.5 ± 9.0, 32.3 ± 9.4, 27.3 ± 7.2, and 24.4 ± 6.5 after patch blocking dura repair of ID. ID is a more common surgical complication in ESLD compared with the transforaminal approach. The endoscopic patch blocking dura repair technique should be considered in type 1 to type 3A of dura tear with good prognosis and clinical outcome. Consideration is made for conversion to open repair in types 3B, 3C and 4 dura tears with fair to poor outcome.