title: Obese patients report modest weight loss after surgery for lumbar spinal stenosis: a study from the Swedish spine register.
abstract: METHODS
  SWESPINE, the Swedish Spine Register, was used for this cohort study.
  
  
  OBJECTIVE
  Our primary aim was to determine weight change in obese patients after surgery for lumbar spinal stenosis (LSS). Our secondary aim was to study any possible associations between weight loss after surgery and improvement in patient-related outcome measures (PROMs).
  
  
  BACKGROUND
  Only meager evidence is available as to how surgery for LSS affects weight and whether weight loss is associated with improvement in PROMs after surgery for LSS.
  
  
  METHODS
  All obese patients who underwent surgery for LSS from January 1, 2006 through June 30, 2008 with a completed 2-year follow-up in SWESPINE were included. Data for weight were collected before surgery and then 1 and 2 years after surgery. The cohort was divided into 3 subclasses (weight stable, weight loss, or weight gain).
  
  
  RESULTS
  Totally, 538 obese patients were enrolled. Mean weight loss was 1.9 kg (95% confidence interval, 1.5-2.3) 1 year after surgery and 2.0 kg (95% confidence interval, 1.5-2.4) after 2 years after surgery. Only 8% of the patients reported a clinically important weight loss (≥10%). No significant differences in PROMs were observed. The weight-stable group reported a mean improvement of 0.22 (standard deviation, 0.36) in EQ-5D, 14 (18) units in the Oswestry Disability Index, 18 (33) units in back pain (visual analogue scale), and 23 (36) units in leg pain (visual analogue scale). The corresponding changes in the weight-loss group were 0.23 (0.35) in EuroQol 5D, 15 (19) in Oswestry Disability Index, 27 (29) in back pain, and 31 (36) in leg pain.
  
  
  CONCLUSIONS
  Modest weight loss was reported 1 and 2 years postsurgery; a small proportion (8%) of these patients reported a clinically important weight loss at the 2-year follow-up. The weight loss was unrelated to changes in PROMs.
  
  
  METHODS
  3.
authors.affiliation: From the Department of Surgical Sciences, Section of Orthopedics, Uppsala University, Sundsvall, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Knutsson
authors.forename: Karl
authors.initials: K
authors.lastname: Michaëlsson
authors.forename: Bengt
authors.initials: B
authors.lastname: Sandén
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D010147:Pain Measurement; D011788:Quality of Life; D012042:Registries; D013130:Spinal Stenosis / Q000150:complications / Q000601:surgery*; D013548:Sweden; D016896:Treatment Outcome; D015431:Weight Loss