The Functional Implications of Transanal Irrigation: Insights from Pathophysiology and Clinical Studies of Neurogenic Bowel Dysfunction

Defecation function is negatively impacted in patients with neurogenic bowel dysfunction (NBD), who require effective bowel care for stool evacuation. NBD comprises fecal incontinence and/or constipation, which can reduce the quality of life and dignity. Transanal irrigation (TAI) is recommended by several clinical guidelines as the second-line treatment after conservative treatment and before surgical options are considered. As the only class in the second-line treatment with an established safety and efficacy profile, the mechanism of action of TAI has not fully been elucidated when administered through a rectal catheter with a balloon. This review examines the current understanding regarding the mechanism of action of TAI, with a focus on the pathophysiology of neurogenic bowel and irregular defecation. By understanding the functional implications of TAI, clinicians may be better able to integrate this modality into bowel care programs, especially for patients with NBD who have significant constipation due to delayed colonic motility and impaired stool emptying with loss of voluntary control of defecation, and those who are unresponsive to conservative treatment, including enemas.