Asian Spine J.  2018 Dec;12(6):1085-1091. 10.31616/asj.2018.12.6.1085.

Cut-off Value for Body Mass Index in Predicting Surgical Success in Patients with Lumbar Spinal Canal Stenosis

• Azimi P
• Yazdanian
• Shahzadi S
• Benzel EC
• Azhari S
• Nayeb Aghaei H
• Montazeri

• KMID: 2430642
• DOI: http://doi.org/10.31616/asj.2018.12.6.1085

Abstract

STUDY DESIGN: Case-control. PURPOSE: To determine optimal cut-off value for body mass index (BMI) in predicting surgical success in patients with lumbar spinal canal stenosis (LSCS). OVERVIEW OF LITERATURE: BMI is an essential variable in the assessment of patients with LSCS.
METHODS
We conducted a prospective study with obese and non-obese LSCS surgical patients and analyzed data on age, sex, duration of symptoms, walking distance, morphologic grade of stenosis, BMI, postoperative complications, and functional disability. Obesity was defined as BMI of ≥30 kg/m². Patients completed the Oswestry Disability Index (ODI) questionnaire before surgery and 2 years after surgery. Surgical success was defined as ≥30% improvement from the baseline ODI score. Receiver operating characteristic (ROC) analysis was used to estimate the optimal cut-off values of BMI to predict surgical success. In addition, correlation was assessed between BMI and stenosis grade based on morphology as defined by Schizas and colleague in total, 189 patients were eligible to enter the study.
RESULTS
Mean age of patients was 61.5±9.6 years. Mean follow-up was 36±12 months. Most patients (88.4%) were classified with grades C (severe stenosis) and D (extreme stenosis). Post-surgical success was 85.7% at the 2-year follow-up. A weak correlation was observed between morphologic grade of stenosis and BMI. Rates of postoperative complications were similar between patients who were obese and those who were non-obese. Both cohorts had similar degree of improvement in the ODI at the 2-year follow-up. However, patients who were non-obese presented significantly higher surgical success than those who were obese. In ROC curve analysis, a cut-off value of ≤29.1 kg/m² for BMI in patients with LSCS was suggestive of surgical success, with 81.1% sensitivity and 82.2% specificity (area under the curve, 0.857; 95% confidence interval, 0.788-0.927).
CONCLUSION
This study showed that the BMI can be considered a parameter for predicting surgical success in patients with LSCS and can be useful in clinical practice.

Keyword

Lumbar spinal stenosis; Predicting; Surgical success; ROC curve; Body mass index

MeSH Terms

Body Mass Index*
Case-Control Studies
Cohort Studies
Constriction, Pathologic*
Follow-Up Studies
Humans
Obesity
Postoperative Complications
Prospective Studies
ROC Curve
Sensitivity and Specificity
Spinal Canal*
Walking