Transanal ultrasound and manometry in the evaluation of fecal incontinence

This preliminary study was undertaken to clarify the role of ultrasonography of anal sphincters in the colorectal laboratory.

Twenty-eight parous female patients with fecal incontinence were evaluated with transanal ultrasonography (TAUS), anal manometry, and pudendal nerve terminal motor latency (PNTML). Ultrasound images were recorded and labeled in centimeters from the anal verge. The continuity of the internal anal sphincter (IAS) was identified as either intact or disrupted. The separation of the external anal sphincter (EAS) was measured at the 1.5-cm level and below. TAUS findings were then compared with anal manometric pressures. Clinical data were obtained by patient interview and examination during TAUS.

Evidence of IAS disruption was associated with significantly decreased mean maximum resting pressures (P = 0.023). EAS separation was inversely proportional to mean maximum squeezing pressures (r = -0.61). In the group of patients offered sphincteroplasty, the IAS was disrupted more often (P = 0.016), mean maximum resting pressures were significantly lower (P = 0.023), mean EAS separation was significantly greater (P = 0.022), and mean PNTML was significantly faster (P = 0.004). Twenty-five percent of patients with normal clinical examinations had significant muscular injury by TAUS requiring sphincteroplasty.

Manometric findings correlate significantly with anal sphincter defects visualized by TAUS. TAUS is useful in the evaluation and management of patients with fecal incontinence.