title: Endoscopic interlaminar approach for intracanal L5-S1 disc herniation: Classification of disc prolapse in relation to learning curve and surgical outcome.
abstract: BACKGROUND
  The full endoscopic interlaminar approach (FEILA) is a minimally invasive procedure to treat intracanal lumbar disc herniation not approachable by endoscopic transforaminal access. Disc prolapses have been classified into three categories according to their position and passing nerve root displacement: (i) type A, in which the nerve root is displaced medially; (ii) type B, in which the nerve root is displaced laterally; and (iii) type C, in which the nerve root is ventrally displaced. We focused on the FEILA technique because it was likely to involve few complications and that provided the advantages of the endoscopic approach.
  
  
  METHODS
  We prospectively evaluated 100 consecutive cases of L5-S1 disc herniations operated on with FEILA, including 85 type A cases, 13 type B, and 2 type C. Patients were evaluated at discharge, 3 months, 6 months and 2 years.
  
  
  RESULTS
  The operating time varied from 15 to 40 min. The use of drills and burrs was necessary to treat type B disc herniations; thus, it was preferable that these cases were operated on later in the learning curve. After surgery, 90% of neurological deficits improved. The Oswestry Disability Index and visual analog scale leg at last follow-up were 15 and 9, respectively. There were no major complications. There were five cases of recurrence; four of which were treated with same technique and with good results.
  
  
  CONCLUSIONS
  FEILA is a safe procedure for the removal of intracanal L5-S1 disc herniations. The late follow-up confirms the stability of the results. We suggest treating type A prolapse at the beginning of the learning curve and type B herniations after sufficient experience in the use of the burrs has been achieved.
authors.affiliation: Department of Neurology and Psychiatry, Neurosurgery, "Sapienza", University of Rome, Rome, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Passacantilli
authors.affiliation: Department of Neurology and Psychiatry, Neurosurgery, "Sapienza", University of Rome, Rome, Italy.
authors.forename: Jacopo
authors.initials: J
authors.lastname: Lenzi
authors.affiliation: Department of Neurology and Psychiatry, Neurosurgery, "Sapienza", University of Rome, Rome, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Caporlingua
authors.affiliation: Department of Neurology and Psychiatry, Neurosurgery, "Sapienza", University of Rome, Rome, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Pescatori
authors.affiliation: Department of Neurology and Psychiatry, Neurosurgery, "Sapienza", University of Rome, Rome, Italy.
authors.forename: Gennaro
authors.initials: G
authors.lastname: Lapadula
authors.affiliation: Department of Neurology and Psychiatry, Neurosurgery, "Sapienza", University of Rome, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Nardone
authors.affiliation: Department of Neurology and Psychiatry, Neurosurgery, "Sapienza", University of Rome, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Santoro
mesh_terms: D000328:Adult; D000368:Aged; D017587:Diskectomy, Percutaneous / Q000379:methods*; D004724:Endoscopy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D059032:Learning Curve; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012447:Sacrum / Q000601:surgery*; D016896:Treatment Outcome
keywords: Disc herniation; endoscopic lumbar surgery; interlaminar approach