title: Minimally invasive lumbar decompression: long-term outcome, morbidity, and the learning curve from the first 50 cases.
abstract: METHODS
  Prospective observational study.
  
  
  OBJECTIVE
  To describe our experience with the first 50 cases of minimally invasive lumbar canal decompression in terms of patient outcome up to 2 years, the learning curve incurred, and complications when compared with our most recent 50 cases.
  
  
  BACKGROUND
  Lumbar canal stenosis is a common condition in the elderly population, the symptoms of which respond well to surgical decompression. A minimally invasive approach offers potential short and long-term benefits to patients but the technique is associated with a learning curve and equivalence to open surgery regarding efficacy and complications needs to be demonstrated.
  
  
  METHODS
  Fifty patients (mean age 70 y) who presented with clinical and radiological features of lumbar canal stenosis and who had failed a period of conservative management underwent lumbar canal decompression through a paramedian oblique, muscle splitting approach using a 16 to 18 mm operating tube and microscope. Outcome was assessed using the Oswestry Disability Index and Short Form-36 at 3 months, 1 year, and 2 years.
  
  
  RESULTS
  Significant clinical improvements were seen at 3 months that were sustained at 1 and 2 years. Clinical outcome improved whereas operative time and complications fell as experience increased, helping to define the learning curve with this technique.
  
  
  CONCLUSIONS
  Minimally invasive lumbar decompression seems to offer patients a clinical benefit comparable to that observed in published open series, with potential advantages in terms of postoperative pain and recovery. However, there is a learning curve and whether this technique offers long-term benefits with regard to a reduction in back pain or postoperative spondylolisthesis is not yet known.
authors.affiliation: Department of Neurosurgery, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia. richard.mannion@nhs.net
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Mannion
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Guilfoyle
authors.forename: Johnny
authors.initials: J
authors.lastname: Efendy
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Nowitzke
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Laing
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Wood
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019299:Decompression, Surgical / Q000379:methods* / Q000639:trends; D005260:Female; D006801:Humans; D059032:Learning Curve; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods* / Q000639:trends; D009017:Morbidity; D011446:Prospective Studies; D011859:Radiography; D013130:Spinal Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome