Body Surface Area: A New Predictor Factor for Conversion and Prolonged Operative Time in Laparoscopic Colorectal Surgery

BACKGROUND: Body surface area is a measurement of body size used in clinical settings. Its impact on laparoscopic colorectal surgery has not been previously studied. OBJECTIVE: The aim of this study was to assess the impact of body surface area on the conversion rate and laparoscopic operative time. DESIGN: This study was conducted as a retrospective analysis of prospectively collected data SETTING: This study was conducted at a single tertiary care institution. PATIENTS: Nine hundred sixteen consecutive patients operated on between January 2004 and August 2011 were identified from a prospective database. MAIN OUTCOME MEASURES: Conversion rate and laparoscopic operative time were analyzed related to age, sex, obesity, disease location (colon vs rectum), type of disease (neoplastic vs nonneoplastic), history of previous surgery, and body surface area; body surface area was calculated by the Mosteller formula. Body surface area was analyzed by the use of median and quartile cutoff values (1.6, 1.8, and 2.0). Multivariate models were adjusted for different confounders. Interaction between body surface area and BMI was ruled out. RESULTS: The conversion rate was 10%. Conversion rates for quartiles 1, 2, 3, and 4 were 4.4%, 8.3%, 12.7%, and 14.8%, p = 0.001. Patients with body surface area >= 1.8 had a higher conversion rate than those with body surface area <1.8 (13.9% vs 5.3%, OR: 2.35 (95% CI: 1.45-3.86; p = 0.0001)). Multivariate analysis showed that body surface area >= 1.8 was associated with conversion (OR: 2, 95% CI: 1.1-3.7, p = 0.02) and a longer operative time after adjusting for sex, age, obesity, disease location (rectum vs colon), and type of laparoscopic approach. LIMITATION: This was a single-institution retrospective study. CONCLUSION: Body surface area is a predictor for conversion and longer laparoscopic operative time. It should be considered when informing patients, selecting cases in the early learning curve, and assessing standard of care.