The following paragraphs summarise the principal findings and
conclusions drawn from results of the studies described in the
| 1. The use of a microtransducer in anorectal manometry avoids many of
the drawbacks of conventional fluid-filled systems. The data obtained
is highly reproducible and probably more accurate.
| 2. The proctometrogram provides a reproducible and useful method of
evaluating the pressure-volume distension characteristics of the
rectum in health and disease. The expected correlation between
compliance and volume is confirmed. There do not appear to be
significant variations in rectal volume or compliance with age in
| 3. The electrophysiological latency of the pudendo-anal reflex in
health is 38.5±5.8 ras ( Mean±SD, n=38 ). It is completely reproducible
and does not appear to vary with age or sex.
| 4. In symptomatic chronic radiation anorectal injury:
| 4.1 The manometric function of the internal anal sphincter is
compromised with diminution in sphincter length, basal pressure and
abnormalities of the rectosphincteric reflex.
| 4.2 The external anal sphincter remains manoraetrically normal. Its
mean motor unit potential duration is increased although the latency
of the pudendo-anal reflex is unaffected. These findings suggest
possible minor damage to its terminal innervation.
| 4.3 The volume and compliance of the rectum are severely diminished,
there being a significant positive correlation between these
parameters. The manometric changes correlate well with symptomatic and
| 5. Following colo-anal sleeve anastomosis for severe chronic
radiation injury to the rectum the organic complications are resolved
but some of the functional abnormalities persist. These are in part
| 5.1 Persisting internal anal sphincter dysfunction.
| 5.2 External anal sphincter dysfunction on rectal distension and
| 5.3 Persisting severe reduction in rectal volume and compliance.
| 5.4 Reduction in rectal sensory threshold volume, although rectal
'proprioception' remains intact.
| 6. Some of the sphincteric and rectal manoraetric and symptomatic
disturbances in chronic radiation injury and those following colo-anal
sleeve anastomosis may be secondary to damage to the myenteric plexus
which is histologically demonstrable.
| 7. Following complete transection of the spinal cord above the sacral
segments, severe constipation may result. The differential effects on
colorectal and pelvic floor motility of sacral anterior root
stimulators in five such patients may be summarised as follows:
| 7.1 There is an increasing influence on striated pelvic floor muscle
activity from S2 to S4.
| 7.2 S2 stimulation results in occasional low pressure phasic
| 7.3 S3 stimulation results in high-pressure phasic colorectal
contractions reminiscent of peristaltic activity. This response is
| 7.4 S4 stimulation results in tonic pressure increases in the colon
and rectum. These may simply be the cosequence of increase in
intra-abdominal pressure due to pelvic floor contraction.
| 8. Two groups of elderly patients who suffer from chronic
constipation are identifiable as defined by the proctometrogram. One
group has a significantly increased rectal capacity and compliance - a
'megarectum' syndrome. The second group shows significant reduction in
rectal volume and compliance demonstrating hypertonicity of the distal
bowel, both groups have blunting of rectal sensation to distension.
Increased gastrointestinal transit times seem mainly due to rectal
stasis. Abnormalities of the pudendo-anal reflex suggest that
neurogenic deficits of the sacral spinal cord may contribute to these
disturbances of colorectal function.
| 9. Electrophysiological studies in young women with chronic
idiopathic constipation suggest the possibility of a neurogenic
deficit in the conus medullaris in the presence of normal sphincteric
| 10. In neurogenic faecal incontinence the latency of the pudendo-anal
reflex is significantly prolonged and its amplitude diminished. It may
be absent in some patients. A significant correlation exists between
the latency of the reflex and the corresponding mean motor unit
potential duration of the external anal sphincter. These findings
confirm the its usefulness as an index of neuropathy in neurogenic
| 11. In genuine female stress urinary incontinence the latency of the
pudendo-anal reflex is significantly prolonged, as are the latencies
of two other polysynaptic sacral reflexes ( dorsal nerve to urethral
sphincter, urethral mucosa to external anal sphincter ). The
electrosensitivity of both the dorsal nerve and urethral mucasa is
significantly blunted. These observations point to a strong neurogenic
element in this disorder. The clinical and manometric response to
pelvic floor physiotherapy is disappointing.