title: Posterior decompression surgery for extraforaminal entrapment of the fifth lumbar spinal nerve at the lumbosacral junction.
abstract: OBJECTIVE
  In this paper, the authors' goal was to elucidate the clinical features and results of decompression surgery for extraforaminal stenosis at the lumbosacral junction.
  
  
  METHODS
  Twenty-eight patients with severe leg pain caused by extraforaminal stenosis at the lumbosacral junction (18 men and 10 women; mean age 68.2 +/- 8.9 years) were treated by posterior decompression without fusion using a microendoscope in 19 patients and a surgical microscope or loupe in 9 patients. The decompression procedures consisted of partial resection of the sacral ala, the L-5 transverse process, and the L5-S1 facet joint along the L-5 spinal nerve. The following items were investigated: 1) preoperative neurological findings; 2) preoperative radiological findings, including plain radiographs, CT scans, selective radiculography of L-5; 3) surgical outcome as evaluated using the Japanese Orthopaedic Association scale for low-back pain (JOA score); and 4) need for revision surgery.
  
  
  RESULTS
  All patients presented with neurological deficits compatible with a diagnosis of L-5 radiculopathy such as weakness of the extensor hallucis longus muscle and sensory disturbance in the L-5 area together with neurogenic claudication. On plain radiographs, 21 patients (75%) and 17 patients (60.7%) exhibited lumbar scoliosis (>or= 5 degrees) and wedging of the L5-S1 intervertebral space (>or= 3 degrees), respectively. The CT scans demonstrated marked osteophyte formation at the posterolateral margin of the L5-S1 vertebral bodies, and a selective L-5 nerve root block was effective in all patients. All patients reported pain relief immediately after surgery. The mean JOA scores were 11.3 +/- 3.8 before surgery and 24.3 +/- 3.4 at the time of the final follow-up examination; the recovery rate was 68.6 +/- 16.5%. The mean estimated blood loss was 66.6 +/- 98.6 ml, and the mean surgical time was 135.3 +/- 46.5 minutes. No significant difference in the recovery rate of the JOA scores or in the surgical time and blood loss was observed between the 2 surgical approaches. Four patients underwent revision posterior interbody fusion for the recurrence of radicular pain as a result of intraforaminal stenosis in 3 patients and insufficient decompression of the extraforaminal area in the remaining patient at an average of 19.5 months after surgery.
  
  
  CONCLUSIONS
  Extraforaminal stenosis at the lumbosacral junction is a rare but distinct pathological condition causing L-5 radiculopathy. Decompression surgery without fusion using a microendoscope or a surgical microscope/loupe is a feasible and less invasive surgical option for elderly patients with extraforaminal stenosis at the lumbosacral junction.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan. morio@sc.itc.keio.ac.jp
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Kota
authors.initials: K
authors.lastname: Watanabe
authors.forename: Ken
authors.initials: K
authors.lastname: Ishii
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuji
authors.forename: Hironari
authors.initials: H
authors.lastname: Takaishi
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakamura
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiba
mesh_terms: D000368:Aged; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000175:diagnosis / Q000601:surgery*; D009460:Neurologic Examination; D010147:Pain Measurement; D011183:Postoperative Complications / Q000175:diagnosis / Q000601:surgery; D011843:Radiculopathy / Q000175:diagnosis / Q000601:surgery*; D012086:Reoperation; D012447:Sacrum / Q000601:surgery; D013123:Spinal Fusion; D013126:Spinal Nerve Roots / Q000601:surgery*; D013128:Spinal Osteophytosis / Q000175:diagnosis / Q000601:surgery