Percutaneous Endoscopic Lumbar discectomy for Foraminal to Superior Migrated Disc at L5- S1 level using the Contralateral Interlaminar Approach: A Technical Case Report

Objective: In cases of foraminal superior migration of L5-S1 HNP, it is very difficult to access by rigid endoscopic procedure. Thus, we attempted a contralateral interlaminar approach to expose the exiting nerve root and contralateral foramen to remove the symptomatic disc and preserve the functional structures. Methods: Between January 2013 and January 2014, five patients who received the percutaneous endoscopic lumbar discectomy for foraminal superior migration of L5-S1 lumbar HNP via a contralateral interlaminar approach were included in this study. Through a contralateral interlaminar approach, we could expose the exiting nerve root only, to remove the symptomatic disc without structural damage. We confirmed the radiologic result with an immediate postoperative MRI, and the clinical result was examined using a VAS. Results: In all cases, the superior migrated disc from the L5-S1 foraminal space was removed completely and demonstrated in the immediate postoperative MRI. The mean preoperative Visual Analogue Score was decreased at the postoperative state, from 7.8 ± 0.84 to 1.4 ± 0.55. Despite the small number of cases, outcomes were satisfactory. Conclusion: We obtained excellent clinical results in treating foraminal to superior migrated disc herniation at L5-S1 using percutaneous endoscopic lumbar discectomy via a contralateral interlaminar approach.