Introduction: Objective assessments of peri-operative risk with spine surgery are necessary to improve surgical risk stratification. Morphometric analysis is an emerging tool with proven utility in predicting postoperative morbidity and mortality in other surgical disciplines. This study evaluates whether morphometrics can be used as a reliable predictor of peri-operative morbidity in patients undergoing lumbar spine surgery.
Methods: The perioperative course of 395 patients (192 male, 203 female) who underwent lumbar surgery at our institution from 2013-2014 was retrospectively reviewed. Pre-operative risk factors such as age, diabetes, smoking, CAD, and BMI were noted. Primary outcome measures included 90 day post-op mortality and morbidity including: unplanned return to OR, 30 and 90 day hospital re-admission, surgical site infection, wound dehiscence, new neurological deficit, DVT, PE, MI, UTI, urinary retention, hospital acquired pneumonia, stroke, and prolonged ICU stay. Psoas muscle area at L4 was measured on preoperative MRI. Total psoas area was divided into tertiles to stratify psoas size as a predictor for complication.
Results: Female patients trended toward a higher complication rate compared to males (34.5% versus 26.0%, p = 0.068). The mean BMI was higher in females with complications than those without (32.62±7.59 versus 30.26±6.53, p=0.021). Age, diabetes, smoking, and CAD were not associated with higher rate of complications. Unlike in males, we were unable to identify any association between psoas area and rate of complication, even after multivariate analysis to account for potential confounders, Odds Ratio 1.22 (p=0.564). Overall, female patients had smaller total psoas area compared to males (19.15±4.8 versus 29.96±8.49, p <0.001).
Conclusions: The application of morphometric analysis to lumbar spinal surgery is feasible. When differentiating for gender, BMI was the only observed predictive marker for rate of complication.
Patient Care: My research will improve patient care by predicting which patients are more likely to have postoperative morbidity after spinal surgery.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Understand the concept of morphometrics; 2) Understand the utility of morphometrics for spine surgery; 3) Understand the limitations of morphometrics.