title: Obesity and posterior spinal fat content: impact on complications in non-complex lumbar spine surgery.
abstract: OBJECTIVE
  Obesity is increasing in prevalence across the world with a potentially very significant impact in spine surgery. This study aimed to characterise this in the setting of neurosurgical spine practise at a single centre in UK. Uniquely, we assess the contribution of posterior spinal fat content to intraoperative complications.
  
  
  METHODS
  All cases of lumbar spine surgery in 1 year were investigated. Case note review was carried out documenting patient demographics, comorbidities, operative details, complications and length of stay. Ninety-four complete datasets were compiled from 128 cases. The posterior spinal fat content was recorded from T2-weighted MRI. Body mass index (BMI) was correlated with each measure using logistic multiple regression and contingency table analysis.
  
  
  RESULTS
  Mean BMI was 28.3 (SD: 5.2) comprising one underweight (BMI <18.5), 26 normal weight (BMI: 18.5-24.9), 32 overweight (BMI ≥25), 33 obese (BMI ≥30) and two morbidly obese patients (BMI ≥40). BMI (coefficient: 0.03, SE: 0.01, p = 0.005) and posterior spinal fat content (coefficient: 0.01, SE: 0.005, p = 0.042) correlated significantly with increasing length of stay. Procedure (p = 0.006) and complication rate (p = 0.010) also correlated with length of stay. Neither BMI nor posterior spinal fat content had a significant effect on the incidence of perioperative complications (p = 0.932, p = 0.742), operating time (p = 0.454, p = 0.748) or blood loss (p = 0.127, p = 0.692). There were three non-operative complications in the obese and overweight groups compared with none in the normal weight group, but this was not significant. Overall complication rate was 15%.
  
  
  CONCLUSIONS
  Obesity and posterior spinal fat content correlate with the length of stay in simple spine surgery. There is a non-significant trend towards increased non-operative complications in overweight and obese patients, which could reach significance with larger numbers and prospective data. Excess posterior spinal fat is not associated with increased operative complications, operating time or blood loss.
authors.affiliation: a Department of Neurosurgery , Charing Cross Hospital, Imperial College Healthcare NHS Trust , London , UK.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Grover
authors.affiliation: a Department of Neurosurgery , Charing Cross Hospital, Imperial College Healthcare NHS Trust , London , UK.
authors.forename: Suresh
authors.initials: S
authors.lastname: Pushpananthan
authors.affiliation: a Department of Neurosurgery , Charing Cross Hospital, Imperial College Healthcare NHS Trust , London , UK.
authors.forename: Hasitha M
authors.initials: HM
authors.lastname: Samarage
authors.affiliation: a Department of Neurosurgery , Charing Cross Hospital, Imperial College Healthcare NHS Trust , London , UK.
authors.forename: Nigel D
authors.initials: ND
authors.lastname: Mendoza
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging* / Q000601:surgery*; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data; D015992:Body Mass Index; D005260:Female; D006801:Humans; D015994:Incidence; D007431:Intraoperative Complications / Q000453:epidemiology*; D007902:Length of Stay; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000000981:diagnostic imaging*; D061646:Operative Time; D050177:Overweight / Q000150:complications / Q000000981:diagnostic imaging; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D013131:Spine / Q000000981:diagnostic imaging* / Q000601:surgery*; D006113:United Kingdom
keywords: Obesity; complications; spine; surgery