title: Endoscopic interlaminar lumbar discectomy with splitting of the ligament flavum under visual control.
abstract: METHODS
  Technical report and cases series.
  
  
  OBJECTIVE
  To present the technique of interlaminar endoscopic lumbar discectomy (ED) with ligamentum flavum (LF) splitting under direct visualization.
  
  
  BACKGROUND
  The most distinguishing advantage of ED is a decrease in tissue trauma, which has been associated postoperatively with less back pain and less adhesion or scar tissue formation. In transforaminal ED the LF is completely spared, whereas in interlaminar ED the LF must be removed under direct visualization, no matter how small the opening may be (3 to 5 mm). It is also possible to keep the LF intact using serial dilators, but this procedure cannot be performed under direct visualization.
  
  
  METHODS
  We performed operations on 16 male and 14 female patients with herniated lumbar disc disease using interlaminar ED with LF splitting under direct visual control. The average age of the patients in the study was 48±15 years. The chief complaint before surgery was radiculopathy confined to 1 leg. The anatomic operative level was L3-4 in 1, L4-5 in 13, and L5-S1 in 16 patients. The ruptured disc had migrated superiorly in 4 cases and inferiorly in 7 cases, and intraoperative electromyographic monitoring was performed in all surgeries. The LF was split with a working channel under direct visualization, and after withdrawing the working channel the split LF closed on its own. The total operation time was 20 to 40 minutes, and the follow-up period was 149±108 days.
  
  
  RESULTS
  There were no abnormal signals on the intraoperative electromyography in any of the cases, and the reported symptoms immediately improved in all patients after the operation. Follow-up magnetic resonance imaging showed a disappearance of the ruptured disc with almost no defect in the LF. There were no operation-associated complications.
  
  
  CONCLUSIONS
  The LF could be safely split under direct visualization using a working channel with a minimal resulting defect. This technique of LF splitting endoscopic discectomy is a feasible approach, even for migrated disc herniation.
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Chi Heon
authors.initials: CH
authors.lastname: Kim
authors.forename: Chun Kee
authors.initials: CK
authors.lastname: Chung
mesh_terms: D000328:Adult; D000368:Aged; D017586:Diskectomy / Q000379:methods*; D004724:Endoscopy; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000473:pathology / Q000601:surgery*; D017843:Ligamentum Flavum / Q000601:surgery; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome