Predicting the complexity of laparoscopic rectal surgery with MRI

Abstract

Rectal cancer surgeons can now choose from at least four different modalities to perform rectal cancer surgery. Technique selection draws on the individual surgeon's preference, enthusiasm, skills, training and comprehension of the evidence. The patient’s characteristics may be a minor contributor to the decision about surgical technique. Recent publications have not been able to demonstrate equivalent pathological outcomes for laparoscopic rectal surgery over open surgery. There may be a subset of patients whose pelvic anatomy is complicated and more suited to open surgery instead of laparoscopic or other minimally invasive procedures. There is no consensus on the radiological criteria to define the difficult surgical pelvis. This research aims to demonstrate the accuracy of the surgeon's intuition in assessing the difficult pelvis, develop objective measures of MRI pelvimetry and assess the relationship between these measurements and surgical outcome. Pelvimetry was performed on MRIs from a randomised controlled trial comparing laparoscopic and open rectal cancer surgery. To define the difficult pelvis, the mean pelvimetry measurements were evaluated for association with successful and unsuccessful surgery as defined by pathological outcomes. The study was unable to identify an objective pelvimetry measure to define the difficult pelvis. A smaller pelvic volume was surprisingly associated with unsuccessful surgery but this was a small effect size. Intuitive judgement of surgical difficulty is inaccurate and inconsistent.