Anorectal physiological assessment - Welcome
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Transcript Anorectal physiological assessment - Welcome
Anorectal physiological
assessment
Perineal trauma study day
13th November 2007
Mrs. Kirsty Cattle MRCS
Research Registrar
Faecal incontinence
Causes of incontinence
Stool factors
Stool delivery
Rectum – storage organ
Anal sphincters
Anatomical
Innervation
Miscellaneous
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Anorectal physiology
Manometry
Rectal sensation
PNTML
Including anorectal inhibitory reflex
Pudendal nerve terminal motor latency
Endoanal ultrasound
Manometry
Resting pressure
Reflects internal anal sphincter function
Normal: > 45 cm H2O, usually ~ 70 cm H2O
Difference between maximum resting anal pressure
and rectal pressure
Pressure (cm H2O)
Maximum
resting pressure
Distance from anal verge (cm)
Squeeze pressure
Reflects external anal sphincter function
Normal in women: ~ 70 cm H2O
The “best squeeze” is documented as the maximum
squeeze pressure, i.e. the biggest increase generated
from resting anal pressure
Pressure (cm H2O)
Maximum
squeeze
pressure
Distance from anal verge (cm)
Anorectal inhibitory reflex
Reflex relaxation of the internal anal sphincter when
the distal rectum is distended
Inflation of balloon in rectum
with 20-30 ml air
Rectal balloon deflated
Pressure (cm H2O)
Time
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
Transrectal technique: Stimulate nerve near ischial
spines, measure time taken to produce twitch of
external anal sphincter
Normal range < 2.2 ms
Statistically different between incontinent patients
and controls, but may be normal in incontinent
patients
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Ultrasound
10 MHz rotating probe
Clear visualisation of
sphincters
Delineation of simple
fistulae
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http://radiology.rsnajnls.org/cgi/content/figsonly/224/2/417
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Other assessments
Barium enema/Colonoscopy
Defaecating proctogram
Summary
Anorectal physiology studies provide us with:
Function and anatomy of sphincters
Assessment of sensation
Estimation of pudendal nerve function
Use:
Treatment options, including planning of surgery
Thank you
Any questions?