Anorectal physiological assessment Perineal trauma study day 13 th November 2007 Mrs. Kirsty Cattle MRCS Research Registrar

Faecal incontinence Causes of incontinence Causes of incontinence Stool factors Stool factors Stool delivery Stool delivery Rectum – storage organ Rectum – storage organ Anal sphincters Anal sphincters Anatomical Anatomical Innervation Innervation Miscellaneous Miscellaneous

Anorectal physiology Manometry Manometry Including anorectal inhibitory reflex Including anorectal inhibitory reflex Rectal sensation Rectal sensation PNTML PNTML Pudendal nerve terminal motor latency Pudendal nerve terminal motor latency Endoanal ultrasound Endoanal ultrasound

Manometry

Resting pressure Resting pressure Reflects internal anal sphincter function Reflects internal anal sphincter function Normal: > 45 cm H 2 O, usually ~ 70 cm H 2 O Normal: > 45 cm H 2 O, usually ~ 70 cm H 2 O Difference between maximum resting anal pressure and rectal pressure Difference between maximum resting anal pressure and rectal pressure

Distance from anal verge (cm) Pressure (cm H 2 O) Maximum resting pressure

Squeeze pressure Squeeze pressure Reflects external anal sphincter function Reflects external anal sphincter function Normal in women: ~ 70 cm H 2 O Normal in women: ~ 70 cm H 2 O The “best squeeze” is documented as the maximum squeeze pressure, i.e. the biggest increase generated from resting anal pressure The “best squeeze” is documented as the maximum squeeze pressure, i.e. the biggest increase generated from resting anal pressure

Distance from anal verge (cm) Pressure (cm H 2 O) Maximum squeeze pressure

Anorectal inhibitory reflex Anorectal inhibitory reflex Reflex relaxation of the internal anal sphincter when the distal rectum is distended Reflex relaxation of the internal anal sphincter when the distal rectum is distended

Time Pressure (cm H 2 O) Inflation of balloon in rectum with ml air Rectal balloon deflated

Rectal sensation Normal values: First sensation 40 – 50 ml Call to stool 80 – 100 ml Urgency 120 – 150 ml

Pudendal nerve studies Measurement of conduction speed in terminal pudendal nerve Measurement of conduction speed in terminal pudendal nerve Transrectal technique: Stimulate nerve near ischial spines, measure time taken to produce twitch of external anal sphincter Transrectal technique: Stimulate nerve near ischial spines, measure time taken to produce twitch of external anal sphincter Normal range < 2.2 ms Normal range < 2.2 ms Statistically different between incontinent patients and controls, but may be normal in incontinent patients Statistically different between incontinent patients and controls, but may be normal in incontinent patients

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Ultrasound 10 MHz rotating probe 10 MHz rotating probe Clear visualisation of sphincters Clear visualisation of sphincters Delineation of simple fistulae Delineation of simple fistulae

Other assessments Barium enema/Colonoscopy Barium enema/Colonoscopy Defaecating proctogram Defaecating proctogram

Summary Anorectal physiology studies provide us with: Anorectal physiology studies provide us with: Function and anatomy of sphincters Function and anatomy of sphincters Assessment of sensation Assessment of sensation Estimation of pudendal nerve function Estimation of pudendal nerve function Use: Use: Treatment options, including planning of surgery Treatment options, including planning of surgery

Thank you Any questions? Any questions?