130 Using Abdominal Fat Ratio to predict difficult laparoscopy – a potential indicator for Robotics/TaTME?

Abstract

Abstract Introduction Minimally-invasive surgery has revolutionised colorectal cancer surgery. Intra-abdominal/visceral adiposity increases the chance of conversion to open surgery. Abdominal fat ratio (AFR) has been identified as predictive for this. New techniques, such as robotic platforms and Trans-anal Total Mesorectal Excision (TaTME), are generally less susceptible to visceral obesity. We hypothesise that AFR can predict difficult laparoscopic surgery and promote selective use of alternative surgical techniques. Methods Hospital coding data identified 117 anterior resection and abdominoperineal excision of the rectum procedures between April 2017 and March 2020. Planned/actual procedure and histological factors were recorded. AFR was calculated using the method from Scott et al (Ann R Coll Surg Engl 2017). Mann-Whitney U testing and binomial logistic regression were used to compare AFR between laparoscopic completed (LC) and conversion to open (CtO) groups. Results 73 cases were completed laparoscopically, 35 converted to open. 9 cases were planned open. AFR between LC and CtO groups was comparable (Median LC = 3.94; CtO = 3.64; U = 1220, p=0.71). Binomial logistic regression showed no relationship between AFR and conversion to open surgery (OR 1.11 95% confidence interval 0.92-1.36, p=0.27). Conclusion No statistically significant differences were found. This may result from the small numbers included but may also reflect the multifactorial nature of intra-operative decision-making. Post-chemoradiotherapy effects and difficulties obtaining safe views through inadequate small bowel retraction or bulky mesentery were cited more often in the conversion group than problematic visceral obesity. Other recognised factors should be considered in future, larger series analysis.