Imaging of parastomal hernia using three-dimensional intrastomal ultrasonography

Background: Parastomal hernia is common in patients with a permanent stoma. At present there is no standard method for imaging a parastomal hernia. The aim of this study was to investigate the value of three-dimensional intrastomal ultrasonography in differentiating between a parastomal hernia and a bulge. Methods: Twenty patients were divided into four groups according to ultrasonography setting and probe cover. All patients were tested using three different ultrasound probe frequencies (9, 13 and 16 MHz). The intrastomal examination was performed during provocation in both the supine and upright positions, with a protector or water-containing balloon surrounding the probe. Results: The sharpest images were obtained using the rectal setting with a water-containing balloon surrounding the probe at 9 MHz in supine and erect positions, for evaluation of both fascia and muscle; in some instances even implanted mesh was detectable. When switched to render mode, the pictures improved in sharpness and it was easier to identify anatomical landmarks. Conclusion: Intrastomal ultrasonography using the rectal setting and a frequency of 9 MHz is a feasible method for imaging a parastomal hernia and differentiating it from an abdominal bulge. The image quality improves when render mode is used.