Anorectal manometry: techniques and clinical applications.

Anorectal manometry has gained wide acceptance as a helpful method to objectively assess the apparatus of defecation provided by the anorectal sphincter. The standard manometric evaluation enables measurement of resting and squeeze pressures, as well as of the length of the functional anal canal (high pressure zone [HPZ]). More detailed assessment of radial and longitudinal pressure profiles can also be generated from vector volume and vector symmetry index assessment. Adjuvant techniques using an intrarectal balloon allow assessment of the rectoanal inhibitory reflex (RAIR), rectal sensitivity, capacity, and compliance. Although anorectal manometry can be used as a diagnostic test in diseases such as Hirschsprung's disease, more often it is used to assess common disorders such as chronic idiopathic constipation and fecal incontinence. Anorectal manometry has also been considered as a preoperative evaluation in patients having abdominal and anorectal procedures during which the state of continence can be jeopardized.