title: Lumbar spinal stenosis: prognostic factors for bilateral microsurgical decompression using a unilateral approach.
abstract: OBJECTIVE
  We describe a prospective cohort study that investigated the effectiveness of microsurgical bilateral decompression using unilateral laminotomy for lumbar spinal stenosis and assessed the factors influencing the outcome.
  
  
  METHODS
  A total of 165 consecutive patients underwent decompression for lumbar spinal stenosis. They were divided into 3 age groups: A (<65 years), B (65-75 years), and C (>75 years). Further classification was performed according to body mass index (BMI): BMI 1 (<26), BMI 2 (26-30), and BMI 3 (>30), anesthesiological risk factors (American Society of Anesthesiologists), and the number of levels decompressed. The outcome was monitored by an independent observer at 1 week, 3 months, and 1 year after surgery. The following parameters were evaluated: pain (visual analog scale and analgesic consumption), functional improvement (Neurogenic Claudication Outcome Score), and walking performance, defined as walking distance x speed (treadmill).
  
  
  RESULTS
  One week after surgery, pain decreased in 85.9% of patients, and a comparison of the pre- and postoperative use of analgesics showed that 38% of nonopioid use and 74% of opioid use were discontinued, whereas nonsteroidal anti-inflammatory drug consumption increased 13%. One year after surgery, pain remained decreased in 83.9% of patients, Neurogenic Claudication Outcome Score increased in 90.3% of patients, and walking performance improved in 92.2% of patients. BMI greater than 30 was the only negative prognostic factor for pain reduction (P = 0.012) and Neurogenic Claudication Outcome Score improvement (P = 0.019). Surprisingly, patients who underwent multilevel decompression benefitted more from surgery than those who underwent single-level decompression.
  
  
  CONCLUSIONS
  Microsurgical bilateral decompression using unilateral laminotomy is an effective surgical option for lumbar spinal stenosis, even in high-risk patients with multilevel stenosis.
authors.affiliation: Center for Spine Surgery, Eilbek Medical Center, Hamburg, Germany. lpapavero@ schoen- kliniken.de
authors.forename: Luca
authors.initials: L
authors.lastname: Papavero
authors.forename: Marco
authors.initials: M
authors.lastname: Thiel
authors.forename: Erik
authors.initials: E
authors.lastname: Fritzsche
authors.forename: Christina
authors.initials: C
authors.lastname: Kunze
authors.forename: Manfred
authors.initials: M
authors.lastname: Westphal
authors.forename: Ralph
authors.initials: R
authors.lastname: Kothe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000758:Anesthesia / Q000009:adverse effects; D015992:Body Mass Index; D015331:Cohort Studies; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D051346:Mobility Limitation; D010149:Postoperative Pain / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology; D011379:Prognosis; D011446:Prospective Studies; D011859:Radiography; D020127:Recovery of Function / Q000502:physiology; D012307:Risk Factors; D013130:Spinal Stenosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology