title: Usefulness of an expandable interbody spacer for the treatment of foraminal stenosis in extremely collapsed disks: preliminary clinical experience with endoscopic posterolateral transforaminal approach.
abstract: METHODS
  Clinical series of patients with degenerative disk disease undergoing an endoscopic posterolateral transforaminal procedure that used a reaming foraminoplasty technique to enlarge the foramen coupled with insertion of the B-Twin expandable spacer.
  
  
  OBJECTIVE
  This retrospective analysis of 107 consecutive patients sought to assess the outcome of this surgical procedure.
  
  
  BACKGROUND
  Reamed endoscopic foraminoplasty under direct endoscopic vision has been shown to be suitable for extremely collapsed disks (>50% total disk height) despite the difficult access, especially at L5-S1. The authors tried to investigate the efficacy of an expandable spacer being inserted by the endoscopic transforaminal approach to solve foraminal stenosis without bone fusion techniques.
  
  
  METHODS
  The procedure consists of bone reaming under direct endoscopic control to wide the foramen followed by insertion of the B-Twin expandable device as a disk spacer to restore partially or to maintain the height of the collapsed disk. Outcome measures included visual analog scale (VAS) for pain, the Oswestry Disability Index (ODI) for functional disability, and radioimaging studies.
  
  
  RESULTS
  Mean follow-up was 27.2 months. Clinical outcome was considered excellent in 64 patients, good in 25, fair in 10, and poor in 8. Results were similar in single and double B-Twin spacer insertions. Postoperative mean values for VAS and ODI scores improved significantly as compared with preoperative data. Mean VAS and ODI scores were significantly higher in patients with fair or poor results than in those with excellent or good outcome. In 2 cases, clear signs of end plate bone resorption in the control computed tomographic scans at 6 months and 12 months leading to a substantial loss of disk height were documented.
  
  
  CONCLUSIONS
  This preliminary study has shown the efficacy of an endoscopic surgical technique for the treatment of foraminal stenosis in extremely collapsed disks.
authors.affiliation: Orthopedic Spine Surgery Unit, Centro Médico Teknon, Barcelona, Spain. rudolf@morgenstern.es
authors.forename: Rudolf
authors.initials: R
authors.lastname: Morgenstern
authors.forename: Christian
authors.initials: C
authors.lastname: Morgenstern
authors.forename: Raimon
authors.initials: R
authors.lastname: Jané
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019299:Decompression, Surgical / Q000295:instrumentation* / Q000379:methods; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000150:complications / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011474:Prosthesis Design; D013130:Spinal Stenosis / Q000209:etiology* / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome