Anal hypertonia in fissures: cause or effect?

Area of Science:

• Gastroenterology
• Colorectal Surgery
• Physiology

Background:

• High anal sphincter pressures are observed in patients with anal fissures.
• This phenomenon has been hypothesized to result from sphincter spasm induced by recording equipment.

Purpose of the Study:

• To investigate whether anal sphincter pressure in patients with chronic anal fissures is elevated due to spasm or a true increase in basal tone.
• To determine the impact of recording probe size on pressure measurements.

Main Methods:

• Anal sphincter pressure was measured in six men with chronic anal fissures and 14 healthy controls using perfused probes of varying diameters (0.4-2 cm).
• Resting pressure, minimum residual pressure during rectal balloon inflation, and maximum voluntary contraction pressure were recorded.

Main Results:

• Patients with anal fissures exhibited significantly higher resting anal canal pressures than controls, regardless of probe size.
• Elevated pressures persisted even with the smallest probe (0.4 cm).
• Minimum residual pressures were also higher in patients with fissures, particularly with a 1.0 cm probe.

Conclusions:

• High resting anal sphincter pressures in chronic anal fissures are likely a true increase in basal sphincter tone, not artifactual spasm from recording assemblies.
• Elevated sphincter pressure may lead to anal lining ischemia, contributing to fissure pain and impaired healing.