title: Bilateral decompression of lumbar spinal stenosis involving a unilateral approach with microscope and tubular retractor system.
abstract: OBJECTIVE
  The authors studied a consecutive series of patients with spinal stenosis in whom surgery was performed by a single surgeon who used a microscopic tubular retractor system (METRx-MD); patients underwent prospective evaluation involving radiography and magnetic resonance (MR) imaging. The objective was to assess the feasibility and surgery-related efficacy of performing unilateral-approach bilateral decompression and utilization of METRx-MD instrumentation in patients with spinal stenosis.
  
  
  METHODS
  Seventeen consecutive patients with spinal stenosis underwent bilateral decompression; surgery was performed via a unilateral approach using METRx-MD instrumentation. The procedures were performed on an outpatient basis after induction of general anesthesia. Preoperative and 3-month follow-up plain radiographs with flexion-extension views were obtained. Preoperative and postoperative MR imaging was also performed. All studies were assessed by a single radiologist blinded to the clinical results. Twenty-two levels were surgically decompressed. The mean operative time was 90 minutes and the mean blood loss was 28 ml per level. Preoperatively stenosis was severe at 13 levels, moderate/severe at eight, and moderate at one. Postoperatively stenosis was absent at 13 levels, mild at seven, mild/moderate at one, and moderate at one. Preoperatively degenerative spondylolisthesis was documented in eight patients, with flexion-extension radiography revealing motion in three cases. On early (3-month) postoperative x-ray films there was no evidence of progression in any case. Grade I spondylolisthesis developed postoperatively in one patient, who remained asymptomatic.
  
  
  CONCLUSIONS
  Minimally invasive bilateral decompression and instrumentation-assisted fusion can be successfully performed via a unilateral approach in patients with acquired spinal stenosis; the procedure can be undertaken on an outpatient basis, with reasonable operative times, minimal blood loss, and acceptable morbidity rates.
authors.affiliation: Mission Hospital Regional Medical Center, Mission Viejo, California, USA. sylvainpalmer@home.com
authors.forename: Sylvain
authors.initials: S
authors.lastname: Palmer
authors.forename: Robert
authors.initials: R
authors.lastname: Turner
authors.forename: Rosemary
authors.initials: R
authors.lastname: Palmer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019299:Decompression, Surgical / Q000295:instrumentation*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008866:Microsurgery / Q000295:instrumentation*; D008875:Middle Aged; D009460:Neurologic Examination; D011183:Postoperative Complications / Q000175:diagnosis; D011446:Prospective Studies; D013130:Spinal Stenosis / Q000175:diagnosis / Q000601:surgery*; D013525:Surgical Instruments; D014057:Tomography, X-Ray Computed