Ambulatory monitoring in anorectal disease
There may be serious flaws in current anorectal investigations because of the unphysiological laboratory setting. An ambulatory system, recording anal and rectal pressures, and electromyography of both somatic and visceral sphincter muscles has been developed to overcome this. Using an analogue system a correlation was discovered between anal pressure and internal sphincter electromyography and three distinct events resulting in the passage of flatus were recorded adding to the understanding of normal anorectal function. In constipation, 'rectal motor complexes' were recorded. These demonstrated a reduction in activity in Slow Transit Constipation confirming a motility disorder of colon and rectum. In Obstructed Defaecation, significantly more anorectal sampling events were appreciated and misinterpreted, resulting in futile attempts at defaecation. This may explain the pathophysiology of this disease. In addition investigation of successful defaecatory events using the newer digital recorder, suggested paradoxical puborectalis activity (Anismus) was a laboratory artifact. In rectal prolapse Resection and rectopexy was established as the treatment of choice. The subsequent recovery of continence being associated with anal pressure recovery. Ambulatory studies confirmed internal sphincter recovery as paramount, the initial dysfunction resulting from rectoanal inhibition from the advancing prolapse. Studying the ileoanal pouch, the functional results of these procedures was excellent. The ambulatory system has shown internal sphincter electromyographic recovery associated with functional improvement. In pouch patients suffering incontinence, high pressure pouch waves were recorded. During the day continence was maintained by the sphincter. At night a number of these events overcame the anal response underlying nocturnal incontinence. Overall, ambulatory techniques were successful and this method of investigation has an important role to play in investigation and assessment of the anorectum.