title: Impact of Elevated Body Mass Index and Obesity on Long-term Surgical Outcomes for Patients With Degenerative Cervical Myelopathy: Analysis of a Combined Prospective Dataset.
abstract: METHODS
  Analysis of a combined prospective dataset.
  
  
  OBJECTIVE
  To evaluate the impact of preoperative body mass index (BMI) on surgical outcomes in degenerative cervical myelopathy (DCM).
  
  
  BACKGROUND
  Although elevated BMI has been shown to have a deleterious impact on outcomes after lumbar spine surgery, limited evidence is available regarding its impact in DCM.
  
  
  METHODS
  Analyses were completed using a combined North American/International prospective surgical DCM dataset from 26 participating centers. Outcome measures included Neck Disability Index (NDI), modified Japanese Orthopedic Association (mJOA) score, and Short Form- 36 (SF-36) scores at 1 year postoperatively. Bivariate and multivariable statistics were used to model the relationship between preoperative BMI, as both a continuous and categorical variable with these outcomes.
  
  
  RESULTS
  Of 757 patients, mean BMI was 27.3 (±5.7) with 17 patients (3.5%) underweight, 271 patients (35.8%) normal weight, 275 patients (36.3%) overweight, and 194 patients (25.7%) obese. Controlling for preoperative mJOA, NDI, smoking status, age, and sex, elevated BMI was associated with increased neck disability at 1 year (P < 0.01). On average, NDI scores were 4.5 points higher (95% confidence interval, CI: 1.6-7.6) for overweight patients and 5.7 points higher (95% CI: 2.6-8.9) for obese patients compared with individuals of normal weight. Obese patients had 0.5 times odds (odds ratio, OR = 0.5, 95% CI: 0.3-0.8, P < 0.01) of showing improvement equal to the minimal clinically important difference of NDI compared with their normal weight counterparts. Although there were strong trends towards reduced SF-36 mental component scores and physical component scores with elevated BMI, no association was found between BMI and 1-year mJOA.
  
  
  CONCLUSIONS
  Increased BMI, particularly obesity, was associated with increased postoperative disability. This represents a potentially modifiable risk factor which clinicians can target to optimize postoperative outcomes.
  
  
  METHODS
  2.
authors.affiliation: Division of Neurosurgery and Spinal Program, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.|Division of Neurosurgery and Spinal Program, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada.|Division of Neurosurgery and Orthopedic Spine Surgery, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Jefferson R
authors.initials: JR
authors.lastname: Wilson
authors.affiliation: Division of Neurosurgery and Spinal Program, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: Tetreault
authors.affiliation: Division of Neurosurgery and Orthopedic Spine Surgery, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Schroeder
authors.affiliation: Division of Neurosurgery and Orthopedic Spine Surgery, Thomas Jefferson University, Philadelphia, PA.
authors.forename: James S
authors.initials: JS
authors.lastname: Harrop
authors.affiliation: Division of Neurosurgery and Orthopedic Spine Surgery, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Prasad
authors.affiliation: Division of Neurosurgery and Orthopedic Spine Surgery, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Alex
authors.initials: A
authors.lastname: Vaccaro
authors.affiliation: Division of Neurosurgery and Orthopedic Spine Surgery, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kepler
authors.affiliation: Division of Neurosurgery and Orthopedic Spine Surgery, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Ashwini
authors.initials: A
authors.lastname: Sharan
authors.affiliation: Division of Neurosurgery and Orthopedic Spine Surgery, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fehlings
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002574:Cervical Vertebrae / Q000601:surgery*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000601:surgery*; D009765:Obesity / Q000150:complications*; D050177:Overweight / Q000150:complications; D063868:Patient Outcome Assessment; D011446:Prospective Studies; D013118:Spinal Cord Diseases / Q000150:complications* / Q000601:surgery*; D016896:Treatment Outcome