Stoma siting and the 'arcuate line' of Douglas: might it be of relevance to later herniation?

Abstract

Preoperative stoma site marking aims to select an appropriate location for stoma positioning but there are no fixed anatomical points of reference. A stoma raised below the arcuate line (AL) of the posterior rectus sheath may be a contributing factor to later herniation. The patients' preferred position for a stoma was marked preoperatively by a nurse stomatherapist in 75 unselected cases. The position of the AL was determined in relation to standard anatomical landmarks (umbilicus, xiphoid process, pubic symphysis and the anterior superior iliac spines). The proportion of patients whose stoma trephine was sited below the AL varied with the anatomical landmark examined. Measurements of symphysis pubis to xiphoid process or height above the iliac spines revealed 36-41% of chosen sites were at or below the AL. In 16 of 29 (55%) women the marked sites were at or below the AL. Of 44 patients who had their site marked above the AL, 23 (53%) were within 2 cm of the AL. In obese patients and those with a waist circumference greater than 100 cm over 50% had their site marked at or within 2 cm of the AL. To ensure a stoma site is above the AL of the posterior rectus sheath its centre should be at least 4 cm above a horizontal line between the anterior superior iliac spines. This might reduce later herniation rates.