Abstract

Introduction : Percutaneous endoscopic lumbar discectomy (PELD) has been widely used procedure. Although various techniques and approaches to herniated disc have been tried to extend the indications of PELD, distal migration with abutment on the medial wall of pedicle is not easy to approach. The purpose of this study is to introduce contralateral approaching portals to be easy of access to distally migrated lumbar disc herniation and to evaluate the clinical results. Material and method : From August 2004 to May 2008, we have experienced ten cases of lumbar disc herniation which were migrated distally, that were Story 3 by the three-storied anatomical house concept and abutted on the medial wall of pedicle. Herniation of disc was occurred at L2-3 in two, at L3-4 in two, and at L4-5 in 6. Eight cases were approached by contralateral transforminal route and two cases by contralateral interlaminar route using 2.5mm working channel endoscope. Performing contralateral transforaminal approaches, 5mm-diametered trephine was used to enlarge the neural foramen in 3 cases. Preoperatively, localization of herniated disc was done by preoperative MRI and accessibility was evaluated by CT and MRI, and postoperatively CT or MRI was taken. Clinical outcomes were evaluated by the improvement of preoperative pain. Result : In all cases, preoperative radiating pain was improved. Low back pain score was improved form 45 points preoperatively to 82 points postoperatively. Numeric rating pain scale was 2.2 against 10 preoperative reference values. There was one case of exit root symptom of approaching side neural foramen in transforaminal route. In the case of contralateral interlaminar approach, mild hypesthesia was developed on the corresponding nerve root dermatome. Simple dural tear was occurred in one case. Conclusions: Percutaneous endoscopic discectomy for distally migrated herniation with abutment on the medial wall of pedicle was successful via contralateral transforaminal or interlaminar approach without significant complications. We suggest these approaches can be one of the advanced techniques to extend the indications of PELD, and can be applied especially at the level of higher than L5-S1.