Hot or cold in anal pain? A study of the changes in internal anal sphincter pressure profiles.

In 26 volunteers without anorectal complaints, and in 31 patients with anorectal problems such as hemorrhoidal disease, anal fissure, and proctalgia fugax, baseline resting anal canal pressures were recorded manometrically for 5 minutes at room temperature (23 degrees C). In 16 volunteers (Group A) and 21 patients (Group B) anorectal manometry was then performed while the anus was immersed in water at varying temperatures (5 degrees C, 23 degrees C, and 40 degrees C). In ten volunteers (Group A') and ten patients (Group B') resting pressures were recorded for an additional 30 minutes following immersion for 5 minutes at 40 degrees C. In all subjects (at least P less than 0.01), resting anal canal pressures diminished significantly from baseline after immersion at 40 degrees C, but remained unchanged in all subjects after immersion at 5 degrees C and 23 degrees C. In Group A', anal canal pressures remained significantly reduced for 15 minutes (P less than 0.02). In Group B', significant reduction in resting pressure lasted 30 minutes (P less than 0.02). Wet heat applied to the anal sphincter apparatus significantly and reproducibly decreased resting anal canal pressures over time, and therefore was likely to benefit patients after anorectal operations and those with anorectal pain.