Evaluation of Anal Continence Function by Advanced Anal Manometric Parameters

Anorectal manometric parameters are influenced by gender and age in subjects with normal bowel function

PURPOSE

Anorectal manometry provides objective information about anorectal function, but its results depend on the examiner's skill, the type of equipment, and subject characteristics like age or gender. This single institution, prospective study was performed to investigate the effect of gender and age on the results of anorectal manometry.

METHODS

All included subjects completed a questionnaire to assess their bowel function. The survey included 13 validated questions (eight on constipation and five on incontinence) and was used to exclude subjects with pathological constipation or incontinence. Subjects with normal bowel function underwent anorectal manometry to measure anal sphincter length (ASL), maximum resting pressure (MRP), and maximum squeeze pressure (MSP), and the results were compared by gender and age.

RESULTS

The mean age of the 154 participants (94 male and 60 female) was 59.1 years. ASL was greater in men (4.23 vs. 3.85 cm, p < 0.001). MRP was not significantly different according to gender (p = 0.93), but MSP was higher in men (190.18 vs. 116.49 mmHg, p < 0.001). ASL did not correlate with age (p = 0.707). MRP was inversely related to age in both men (R (2) = 0.152, p < 0.001) and women (R (2) = 0.282, p < 0.001), and MSP only in women (R (2) = 0.210, p < 0.001).

CONCLUSIONS

Anorectal manometric parameters are influenced by gender and age. This should be taken into consideration when interpreting manometric readings in a clinical setting.

Determinant of anal resting pressure gradient in association with continence function

Background/Aims

Gradient of resting pressure across the anal canal, which is known to have a role in continence mechanism, has 2 components of determination; pressure and length factor of the anal canal. This study evaluates which factor between them plays more significant role for the determination of the gradient in association with continence function.

Methods

Anal manometric measurements of 69 patients with fecal incontinence and 60 controls were retrospectively reviewed. In addition to resting pressure gradient, typical manometric parameters such as maximum resting pressure, basal resting pressure, length of the anal canal, length of high pressure zone and relative position of highest pressure, which were measured with rapid pull-through technique were all contrasted.

Results

Demographics of the 2 groups were similar. Maximum resting pressures of patients with incontinence and controls were 59.1 ± 28.3, 74.6 ± 24.0 mmHg (P = 0.001), respectively. Basal resting pressures were 5.7 ± 6.4 and 7.3 ± 3.9 mmHg (P = 0.097), lengths of the anal canal were 35.8 ± 9.1 and 38.1 ± 8.3 mm (P = 0.133), lengths of high pressure zone were 21.2 ± 6.7 and 23.3 ± 6.5 mm (P = 0.091), relative positions of highest pressure were 69.2 ± 10.6 and 70.1% ± 14.9% (P = 0.717) and resting pressure gradients were 2.28 ± 1.08 and 2.74 ± 1.14 mmHg/mm (P = 0.019), respectively. Difference was significant in maximum resting pressure and resting pressure gradient, but not in length factors such as full length of the anal canal, length of high pressure zone and relative position of highest pressure.

Conclusions

Proximal location of high pressure zone in incontinent patients is not definite and resting pressure gradient of the anal canal depends more on pressure factor than length factor in association with continence function.