Sex differences in the splenic flexure.

INTRODUCTION Anecdotally, surgeons claim splenic flexure mobilisation is more difficult in male patients. There have been no scientific studies to confirm or disprove this hypothesis. The implications in colorectal surgery could be profound. The aim of this study was to assess quantitatively whether there is an anatomical difference in the position of the splenic flexure between men and women using computed tomography (CT). METHODS Portal venous phase CT performed for preoperative assessment of colorectal malignancy was analysed using the hospital picture archiving and communication system. The splenic flexure was compared between men and women using two variables: anatomical height corresponding to the adjacent vertebral level (converted to ordinal values between 1 and 17) and distance from the midline. RESULTS In total, 100 CT images were analysed. Sex distribution was even. The mean ages of the male and female patients were 68.1 years and 66.7 years respectively (p=0.630). The mean vertebral level for men was 8.88, equating to the inferior half of the T11 vertebral body (range: 1-17 [superior half of T9 to inferior half of L2]), and 11.36 for women, equating to the inferior half of the T12 vertebral body (range: 4-16 [superior half of T10 to superior half of L2]). This difference was statistically significant (p=0.0001) and is equivalent to one whole vertebra. The mean distance from the midline was 160.8mm (range: 124-203mm) for men and 138.2mm (range: 107-185mm) for women (p<0.0001). CONCLUSIONS The splenic flexure is both higher and further from the midline in men than in women. This provides one theory as to why mobilising the splenic flexure may be more difficult in male patients.