title: Obesity and self-reported outcome after minimally invasive lumbar spinal fusion surgery.
abstract: OBJECTIVE
  Many patients undergoing lumbar spine fusion are overweight or obese. The relationship between body habitus and outcome after lumbar spine fusion surgery is not well defined.
  
  
  METHODS
  We analyzed a prospectively maintained database of self-reported pain and quality of life measures, including Visual Analog Scale pain score, Short Form 36, and Oswestry Disability Index. We selected patients undergoing minimally invasive transforaminal lumbar interbody fusion between September 2002 and June 2006 at a single institution. We used linear regression models and mixed-effects linear models to examine the relationships between body habitus and self-reported outcomes.
  
  
  RESULTS
  The analysis identified 110 patients meeting the study criteria, with a median follow-up period of 14.8 months. The mean age was 56 years, mean height was 169 cm, and mean weight was 82.2 kg. The mean body mass index (BMI) was 28.7 kg/m2; 31% of patients were overweight (BMI, 25-29.9), and 32% of patients were obese (BMI, >30). Linear regression analysis did not identify a correlation between weight or BMI and pre- and postsurgery changes in any of the outcome measures. The significant findings observed in the mixed-effects linear models were that the changing patterns of Short Form 36 Body Pain subscale and Short Form 36 Vitality subscale varied significantly by category of BMI (P = 0.01 and P = 0.002, respectively), but not significantly if continuous BMI was used (P = 0.53 and P = 0.46, respectively). BMI correlated marginally with estimated blood loss (P = 0.08), but not operative time, length of hospital stay, or complications.
  
  
  CONCLUSIONS
  Among this cohort of minimally invasive lumbar fusion patients, body habitus measured by BMI, weight, or height did not have a significant relationship with most self-reported outcome measures, operative time, length of hospital stay, or complications. Obesity should not be considered a contraindication to minimally invasive lumbar spinal fusion surgery.
authors.affiliation: Section of Neurosurgery, Department of Surgery, University of Chicago Medical Center and Pritzker School of Medicine, Chicago, Illinois, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Rosen
authors.forename: Sherise D
authors.initials: SD
authors.lastname: Ferguson
authors.forename: Alfred T
authors.initials: AT
authors.lastname: Ogden
authors.forename: Dezheng
authors.initials: D
authors.lastname: Huo
authors.forename: Richard G
authors.initials: RG
authors.lastname: Fessler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D004185:Disability Evaluation; D006304:Health Status; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects; D009765:Obesity / Q000150:complications*; D010147:Pain Measurement; D011788:Quality of Life; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000150:complications / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult