Structural Preservation Percutaneous Endoscopic Lumbar Interlaminar Discectomy for L5-S1 Herniated Nucleus Pulposus.

Objective. Structures such as ligamentum flavum, annulus, and lamina play an important role in the segmental function. We proposed the surgical technique for achieving the sufficient preservation of segmental structures, in spite of sufficient removal of pathologic disc in the L5-S1 using the ligamentum flavum splitting and sealing technique. Methods. We retrospectively analyzed 80 cases that underwent percutaneous endoscopic lumbar discectomy for L5-S1 herniated nucleus pulposus, using the ligamentum flavum splitting and sealing technique between January 2011 and June 2013. Outcomes were assessed using VAS (leg, back), MacNab's criteria, and the immediate postoperative MRI for all patients. Structural preservation was classified as complete, sufficient, and incomplete. Results. The surgical results are as follows: 65 cases were complete, 15 cases were sufficient, and 0 cases were incomplete. The VAS was decreased at the last follow-up (leg: from 7.91 +/- 0.73 to 1.15 +/- 0.62; back: from 5.15 +/- 0.71 to 1.19 +/- 0.75). A favorable outcome (excellent or good outcome by MacNab's criteria) was achieved in 77 patients (96.25%). During the follow-up period, 2 cases (2.5%) of recurrence have occurred. Conclusion. According to the result, we could obtain the favorable clinical and radiological outcomes while simultaneously removing pathologic discs using the ligamentum flavum splitting and annular fissure sealing technique.