Transrectal Ultrasound, Manometry, and Pudendal Nerve Terminal Latency Studies in the Evaluation of Sphincter Injuries

“…These tests provide us with an objective evaluation of anal neuromuscular function that would not be otherwise detected on clinical examination.”

This article summarizes the techniques for anal testing of patients with fecal incontinence, describing the type of equipment used for each and study the interpretation of the following:

• Transrectal (endoanal) ultrasound: A validated technique that is highly accurate for detecting anal sphincter defects, as determined by a number of studies in the 1990’s using 2D imaging with a 360o endoanal probe. Images provided show normal and abnormal ultrasound findings.
• Anal manometry: The use of an anal balloon or specialty catheter to measure sensation, pressures, capacity, and compliance within the anal canal.
• Pudendal nerve latency: Measurement of terminal latency response of the pudendal nerve.