Physiologic study

1. Seminar on
Physiologic testing to
assess pelvic floor and
anorectal disorder
Presenter : Dr Biswajit Deka
PGT, 2nd year
Moderator : Dr R C Shyam
Asstt. Proof
Deptt. Of Surgery ,SMCH

2. Introduction
Physiologic testing has been used to assess pelvic floor
and anorectal disorder for past 35 yrs, but only in the past
two decades has this testing become of value for clinical
use. These tests are performed in conjunction with history,
diary of disorder ,physical examination, endoscopy and
often imaging studies.Physiologic tests have provided or
confirmed a diagnosis in 75% pts with constipation , 66%
pts with incontinence & 42% pts with chronic anorectal
pain.

3. • The original physiologic testing equipment was
home-made.
• Past two decades- commercial equipment
• Even now a major problem is good set of
normal values for healthy pts of both sexes and
of all ages
• Tests complement each other

4. • Tests include :
Manometry
Defecography
Anal ultrasound
MRI
Transit time
Pudendal nerve terminal motor latency (PNTML)
Electromyography (EMG)

5. Manometry
• Tech for measuring pressure in rectum and anus, and
pressures & reflexes elicited by voluntary actions or by
local stimuli.
Indications :
1.Sphincter defect - located and quantified.
2.Constipation - mainly outlet obstruction type
( loss of anorectal inhibitory reflex : Hirschsprung dis)
3.Anorectal pain syndrome : abnormal pressure within
the sphincter mechanism
4.The study is conducted to establish a baseline when
an anorectal or pelvic floor procedure is contemplated.

6. For example, if biofeedback or a surgical procedure is
to be used for incontinence or constipation, a pre- and
post procedure study provides the means to quantify a
change.
Equipment
• probe
• transducers
• recorder
• hydraulic pump for water infusion methods
• Methods: the water-perfusion method and the solid-
state method. The choice is based on cost and user
experience.

7. Probes
• water perfusion, solid state, small balloon, or large
balloon;
• open-tipped or side- opening.
• The open-tipped and balloon probes have fallen into
disfavor.
• most popular : water-perfusion probe, (inexpensive,
durable, and easy to use )
The solid-state catheter is expensive and fragile, but it
gives the most accurate, reproducible results.

8. Hydraulic Water-Perfusion Machines
The water-perfusion machine is a key part of the
water- perfusion method. The water is driven
through each of the individual channels in the tube
at a chosen rate; the water perfuses through the
holes near the tip and thus is exposed to pressure
changes.

9. Amplifier/Recorder
Many recording devices are available, but at
present computerized systems with small amplifiers
and recorders are preferable.
Transducers
Transducers are an essential part of the water-
perfusion system.
The mechanical water pressure is changed to
electrical signals in the transducer.

11. Preparation for manometry
• A simple small, tap-water enema or commercially
prepared enema to empty stool from the rectum
and anus before coming for the examination.
• left lateral position with the hips and knees
flexed to 90 degrees.
• A digital rectal examination done to verify that
the rectum is empty, sense the direction of the
rectal lumen, and recognize any abnormalities.

12. Resting Pressure
•The probe is introduced higher than the 5-cm level
• left in place for 5 minutes to permit the temperature to equalise to body
temperature and the sphincter mechanism to relax to a baseline.
• Probe oriented so that the posterior sensor corresponds to the recording of
the posterior aspect of the anus.
•Station pull-through technique (MC) or the continuous pull-through
technique.
• The catheter is pulled through at 1-cm intervals, stopping to record the
pressure at each increment for 10 seconds.
• As the sensors enter the sphincter mechanism, the pressure will be seen
to increase over the baseline rectal pressure.
•A stepwise increase in pressure as the sensors progress distally
• As the sensor leaves the sphincter mechanism, the pressure will drop to
zero.

13. Squeeze Pressure
• The probe is reinserted to at least the 6-cm level and
reoriented.
• The probe is again removed at 1-cm increments.
• The patient is instructed to squeeze the sphincter muscles as if
to stop a bowel movement and hold the squeeze for 3
seconds.
• To avoid using accessory muscles, especially the gluteals
Using the continuous pull-through method, the patient is asked to
squeeze and hold the squeeze as a motor pulls the catheter
through the sphincter mechanism. The pull through can be
performed several times and the results can be averaged

14. Reflexes
• Probe positioned in high pressure zone in anal canal
to observe for RAIR
• 10cc air injected into balloon & pressure observed
for 10 sec
• Air inflated: 20,30,40,50 ,60cc increment
• The recording normally shows a relaxation from
baseline, which verifies the intact reflex from the
stimulated rectal wall to the internal sphincter.

15. • Probe positioned in high pressure zone
again
• Pt asked to cough
• Cough reflex elicited
• The squeeze pressure increases
involuntarily to counteract the increased
abdominal pressure .

16. Strain maneuver
• Probe positioned in high pressure zone
• Pt instructed to bear down as if to defecate for at
least 5 sec
• The pressure normally reduce for a few sec similar to
RAIR
• Repeated after 30 sec
• Result - avg of total

17. Interpretation
Normal
• Upper anus: pressure is lower anteriorly
• Mid anus: pressure equal circumferencially
• Distal anus: pressure is less posteriorly
Overall ,men & young pts: higher pressure

18. Interpretation of resting pressure
• The pressure at high pressure zone at rest after a
period of stabilisation
• Contribution from both internal & external sphincters
(internal sphincter :75-80% of total )
• Women : 52mm Hg (39-65)
• Men : 59mm Hg (47-71)
• Low : incontinence
• High :a/w anorectal pain
Anal fissure
Ideal for lateral internal Sphincterotomy .
Relaxation of internal sphincter spasm can be
done 10mg sublingual nitroglycerin

19. Interpretation of squeeze pressure
• Pressure above resting pressure
• Mainly by external sphincter
• Women : 128mm Hg
• Men : 228 mmHg
• Low :a/w sphincter injury , nerve damage
• High : pelvic floor spasm (anismus)
Anorectal pain

20. Interpretation of squeeze duration
The length of time the pt can maintain a squeeze
pressure above the resting pressure
• Should be >30sec at >50% of max squeeze pr
• Unable to maintain squeeze: Incontinence
• Few type 1 motor nerve
• Conversion from type 1 to type 2 in older pts
• Actual importance for this part in manometry not
clear

21. Interpretation of reflex studies
The RAIR is the transient decrease in resting anal
pressure by >25% of basal pressure in response to
rapid inflation of a rectal balloon ,with subsequent
return to baseline.
• Decrease in pr: measure of internal sphincter
relaxation
• Mega-rectum : poor reflex
• Normal RAIR: rules out Hirschsprung dis
• pts with fissure : rebound phenomenon

22. Defecography
•Defecography is a dynamic fluoroscopic examination performed
with rectal contrast to study the anatomy and function of the
anorectum and pelvic floor during defecation.
•This procedure may be performed using standard radiology
equipment and with relatively low radiation exposure.
•The specific points to be analysed may be captured on still
radiographs, but cine-radiography provides a better look at the
potential patho-physiologies that may influence and perhaps
interfere with successful and normal evacuations.

23. Indication
• As part of the evaluation of a patient who
has an outlet obstruction type of
constipation. .
• This study may be used after a repair for
outlet obstruction to compare the efficiency
of the defecation process before and after
the procedure.

24. Interpretation
Anorectal angle
• Proctographic angle between the mid axial
longitudinal axis of rectum and anal canal.
• At rest : 90-110 degree
• Squeeze : acute (75 to 90)
• Evacuation : obtuse (110 to 180)

25. Perineal descent
•Caudad movement of pelvic floor with straining
•Pubococcygeal line
•Squeezing : rise up
•Evacuation : lowers down
•Should not rise or fall >4cm of pubococcygeal line
•Greater descent : decreased muscle tone
(pudendal nerve injury)
Anal canal length
•Width should not exceed 2.5cm
•Wider opening : incompetent muscle

26. Efficiency of emptying
• Normal : complete emptying
• 90% : lower limit of normal
• Ileal pouch :60% evacuation is lower limit of normal
Rectocele
• MC finding in defecography
Anismus
• Non-relaxing of puborectalis or levator muscles
• Normal evacuation : 10sec
• pts with anismus : >30sec

27. Balloon expulsion test
•The balloon expulsion test measures the ability of the patient to
expel a balloon inflated with 50–60 mL of water
•Condoms and Foley catheter balloons used
•Patients with outlet obstruction are not able to pass this balloon
readily
• The problem is that some patients may pass the balloon, but have
undetected outlet obstruction
•Conversely, patients with outlet obstruction may call upon
compensatory mechanisms to pass the balloon

28. Anal ultrasound
• If a defect in the sphincter mechanism is
suspected, USG is the diagnostic technique of
choice.
• It is most useful in the work-up of incontinence.
• The obstetric injury is readily seen,
• Ability to find the defect approaches 100%

29. .
Anal Ultrasound
• To look for anatomic abnormality of the anal sphincters.
• Ultrasound has replaced EMG as the best means to
define an injury
Magnetic Resonance Imaging
• MRI of pelvic floor function is developing rapidly.
• Identification of the anal and rectal structures easy
on MRI because the peri-rectal fat shows a high
degree of contrast when compared with the
musculature.
• Indications sepsis, trauma, congenital abnormalities,

30. EMG of anal sphincter
•Primarily in evaluating fecal incontinence.
• a means of assessing the motor unit.
•The integrity of the muscle assessed & its nerve supply.
•The integrity of external anal sphincter innervation after sphincter
injury demonstrated.
•Sphincter re-innervation secondary to pelvic neuropathy
demonstrated.
• Used to “map” specific anatomic sphincter defects, now replaced
by anal ultrasonography ( simple, accurate, and painless).
•To demonstrate appropriate relaxation and contraction of the anal
muscle
•used in biofeedback therapy

31. • Concentric needle EMG
• Single fibre EMG
• Surface Electrodes

32. Pudendal Nerve Terminal Motor Latency
• The pudendal nerve : S2, S3, S4
• along the lateral pelvic wall down to near the ischial spine where it
exits the pelvis to supply the external anal sphincter and the peri-
urethral muscles through its terminal perineal branch.
• Prolongation in the pudendal nerve conduction indicates injury to
the pudendal nerve sheath that results in focal demyelination—
slowing of conduction.
• Testing is usually done with a St. Mark’s electrode
• The electrode has a constant distance of 50 mm between
stimulation of the nerve and recording of the external anal
sphincter response.

33. • Latency between stimulation and response can then be
recorded
• This latency reflects the myelin function of the peripheral
nerve.
• Therefore, a normal PNTML does not exclude partial
damage
• However, when unilaterally or bilaterally severely
prolonged, PNTML has been shown to affect results
after sphincter repair

34. Evaluation of Transit
• The time it takes for food to travel through the digestive tract
is known as bowel transit time.
• Gastric emptying, small bowel transit, and colonic transit may
be studied.
• Dependent on diet and varies from person to person.
• dietary history and bowel evacuation history
• Dietary history can be evaluated for fiber, fat, and calorie
intake.

35. • Stool history - delineate the extent of the patient’s
problem.
• In patients complaining of chronic constipation who
believed that they had less than or equal to 3
stools/week for > 6 months, a 4-week stool diary
revealed that only 49% actually met this criteria.
• The remaining 51% of patients had, on average, 6
stools/week.
• This study also showed that a history of psychiatric
illness was 5 times more frequent among those whose
bowel symptoms correlated poorly with objective
evidence of constipation.

36. • Colonic transit
• Small bowel transit
• Radionuclide transit

37. Colonic transit
• Use marker test
• One marker tablet- 24 marker : on day 0
• Day 5- supine abdominal film
• Determines number & position of remaining markers
• 5 or less markers - normal
• >5 : pattern of residual marker noted
• Diffuse scattering in colon: colonic inertia or
decreased motility
• Recto-sigmoid region: pelvic outlet problems

38. Radionuclide transit
• Measured by radionuclide gamma scintigraphic tech
• Major advantage : 24-48 hrs of scanning needed
compared to 5-7 days for marker test completion.

39. Small bowel transit
• Before surgical Tx of constipation -pt may have
global motility problem
• Measured by Breath Hydrogen Analysis
• Depends on bacteria in large intestine to
metabolise lactulose.
• Meal of lactulose & bean

40. • Fermentation of meal in colon
• Fermentation release hydrogen -absorbed &
excreted by lungs
• Time taken to a 20 ppm increase in H2 in breath
correlates with small bowel transit
• Aslo measured by scintigraphy (adv: measure
gastric emptying)

41. • Radiation exposure with scintigraphy is highest
for the colon and can be reduced by the
administration of laxatives after the procedure
• Radiation to ovaries is less than in a plain
abdominal x-ray.

49. Thank you…