title: Percutaneous endoscopic lumbar discectomy for migrated disc herniation: classification of disc migration and surgical approaches.
abstract: Percutaneous endoscopic lumbar discectomy (PELD) for migrated disc herniations is technically demanding due to the absence of the technical guideline. The purposes of this study were to propose a radiologic classification of disc migration and surgical approaches of PELD according to the classification. A prospective study of 116 consecutive patients undergoing single-level PELD was conducted. According to preoperative MRI findings, disc migration was classified into four zones based on the direction and distance from the disc space: zone 1 (far up), zone 2 (near up), zone 3 (near down), zone 4 (far down). Two surgical approaches were used according to this classification. Near-migrated discs were treated with "half-and-half" technique, which involved positioning a beveled working sheath across the disc space to the epidural space. Far-migrated discs were treated with "epiduroscopic" technique, which involved introducing the endoscope into the epidural space completely. The mean follow-up period was 14.5 (range 9-20) months. According to the Macnab criteria, satisfactory results were as follows: 91.6% (98/107) in the down-migrated discs; 88.9% (8/9) in the up-migrated discs; 97.4% (76/78) in the near-migrated discs; and 78.9% (30/38) in the far-migrated discs. The mean VAS score decreased from 7.5 +/- 1.7 preoperatively to 2.6 +/- 1.8 at the final follow-up (P < 0.0001). There were no recurrence and no approach-related complications during the follow-up period. The proposed classification and approaches will provide appropriate surgical guideline of PELD for migrated disc herniation. Based on our results, open surgery should be considered for far-migrated disc herniations.
authors.affiliation: Department of Neurosurgery, Wooridul Spine Hospital, 47-4 Chungdam-dong Kangnam-gu, Seoul 135-100, South Korea.
authors.forename: Seungcheol
authors.initials: S
authors.lastname: Lee
authors.forename: Seok-Kang
authors.initials: SK
authors.lastname: Kim
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Won Joong
authors.initials: WJ
authors.lastname: Kim
authors.forename: Won-Chul
authors.initials: WC
authors.lastname: Choi
authors.forename: Gun
authors.initials: G
authors.lastname: Choi
authors.forename: Song-Woo
authors.initials: SW
authors.lastname: Shin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017587:Diskectomy, Percutaneous / Q000379:methods*; D004724:Endoscopy / Q000379:methods*; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000145:classification* / Q000473:pathology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D016896:Treatment Outcome