307 - Low Body Mass is a Negative Independent Risk Factor in Elective Cervic...

General Session: Cervical Degenerative

Presented by: S. Horn - View Audio/Video Presentation (Members Only)

Author(s):

S. Horn(1), O. Bono(1), B. Diebo(2), G. Poorman(1), B. Beaubrun(1), A. Sure(1), C. Jalai(1), N. Foster(1), P. Passias(1)

(1) St. Francis Hospital & Medical Center, Spine Institute of Connecticut, Hartford, CT, United States
(2) University of California, Berkeley, Austin, TX, United States
(3) St. Francis Hospital & Medical Center, Hartford, CT, United States

Abstract

Summary: Associations between body mass index (BMI) and complications following cervical spine surgery are controversial. This study investigated 7,452 patients on the National Surgery Quality Improvement Program (NSQIP) and revealed that low-body-mass (BMI < 18.5) is a strong predictor of increased complications, particularly in less-invasive surgeries. While recent literature has focused on obesity, patients with abnormally low BMI may represent malnourished patients. Preoperative nutritional consultation may be warranted to medically optimize patients and avoid complications.

Hypothesis: Low BMI patients will have higher complication rates in cervical spinal surgery compared to normal BMI patients. Design: Retrospective review of the American College of Surgeon's National Surgery Quality Improvement Program (NSQIP) from 2011-2013.

Introduction: Obesity is a concern in surgical treatment for spine pathology, but associations between body mass index (BMI) and complications following cervical spine surgery are unclear.

Methods: Patients were classified by BMI into 5 categories - underweight (BMI< 18.5 kg/m2), normal weight (20-29.9), Obesity-1 (30-34.9), -2 (35-39.9), and -3 (≥40). Surgical invasiveness (SI: levels fused/decompressed/interbody, osteotomy, revision) dichotomized patients by 75th percentile into Low-SI (mean 1.8 levels fused), and High-SI (mean 6.2 levels fused). Poisson and logistic regression evaluated BMI category as a risk factor for individual and grouped complications, controlling for Charlson Comorbidity Index (CCI), age, >10% weight loss within 6 months, and SI.

Results: CCI was similar between normal and underweight patients (Low-SI: p=0.998, High-SI p=0.556). Controlling for confounders, compared to normal weight patients, underweight patients undergoing Low-SI had more cardiopulmonary complications (OR 3.2 [1.0-9.7]), infections (OR 5.2 [2.3-12.1]), surgical complications (OR 6.1 [1.8-20.9]), airway complications (OR 5.5 [1.7-18.1]), and reintubation (OR 6.7 [2.0-22.9])(all p< 0.05). In High-SI procedures, underweight patients required more blood transfusions (OR 2.8 [1.3-6.1]). Similar trends were found in both anterior and posterior procedures. In Obesity-1-3 patients, despite higher rates of diabetes, hypertension, and higher average CCI (all p< 0.001), high BMI was not associated with an increase in any complication-rates in Low- or High-SI (p>0.05).

Conclusions: Despite comparable comorbidity status, underweight patients experience greater complication rates in less invasive cervical surgeries. While recent literature has focused on obesity, patients with abnormally low BMI may warrant preoperative nutrition consultation and optimization.