Anatomical siting of the splenic flexure using computed tomography

INTRODUCTION Often, left-sided colorectal surgery requires splenic flexure mobilisation (SFM) to allow a tension-free anastomosis to be carried out. This step is difficult and not without risk. We investigated a system of anatomical siting of the splenic flexure using computed tomography (CT). METHODS The Shrewsbury Splenic Flexure Siting (SSFS) system involves siting of the splenic flexure using the vertebral level (VL) as a reference point. We asked three surgical registrars (SRs) to analyse 20 CT scans of patients undergoing colonic resection to ascertain the anatomical site of the splenic flexure using the SSFS system. The distance from the centre of the vertebral body to the lateral edge (CVBL) of the splenic flexure was measured, as was the distance from the centre of the vertebral body to the inner abdominal wall (CVBI) along the same line, on axial images. RESULTS VL assessment demonstrated substantial inter-observer agreement with a kappa (κ) value of 0.742 (95% confidence interval (CI), 0.463-0.890). CVBL and CVBI demonstrated very strong inter-observer agreement (CVBL: κ = 0.905 (95% CI, 0.785-0.961); CVBI: 0.951 (0.890-0.979) (p<0.001). Overall, there was strong correlation between assessments by all three SRs across the three variables measured. CONCLUSIONS The SSFS system is an accurate method to site the splenic flexure anatomically using CT. We can use the SSFS system to develop a validated scoring system to help colorectal surgeons assess the difficulty of SFM.