Discrepancies in anal manometric pressure measurement--important or inconsequential?

ANORECTAL MANOMETRY STANDARD OF A BRAZILIAN POPULATION AT PRODUCTIVE AGE WITHOUT PELVIC FLOOR DISORDERS: A PROSPECTIVE VOLUNTEERED STUDY

Background:

Due to the lack of normal standards of anorectal manometry in Brazil, data used are subject to normality patterns described at different nationalities.

Aim:

To determine the values and range of the parameters evaluated at anorectal manometry in people, at productive age, without pelvic floor disorders comparing the parameters obtained between male and female.

Methods:

Prospective analysis of clinical data, such as gender, age, race, body mass index (BMI) and anorectal manometry, of volunteers from a Brazilian university reference in pelvic floor disorders.

Results:

Forty patients were included, with a mean age of 45.5 years in males and 37.2 females (p=0.43). According to male and female, respectively in mmHg, resting pressures were similar (78.28 vs. 63.51, p=0.40); squeeze pressures (153.89 vs. 79.78, p=0.007) and total squeeze pressures (231.27 vs. 145.63, p=0.002). Men presented significantly higher values of anorectal squeeze pressures, as well as the average length of the functional anal canal (2.85 cm in male vs. 2.45 cm in female, p=0.003).

Conclusions:

Normal sphincter pressure levels in Brazilians differ from those used until now as normal literature standards. Male gender has higher external anal sphincter tonus as compared to female, in addition a greater extension of the functional anal canal

Hypothesized summative anal physiology score correlates but poorly predicts incontinence severity

AIM

To explore the relationship between such a construct and an existing continence score.

METHODS

A retrospective study of incontinent patients who underwent anal physiology (AP) was performed. AP results and Cleveland Clinic Continence Scores (CCCS) were extracted. An anal physiology score (APS) was developed using maximum resting pressures (MRP), anal canal length (ACL), internal and external sphincter defects and pudendal terminal motor latency. Univariate associations between each variable, APS and CCCS were assessed. Multiple regression analyses were performed.

RESULTS

Of 508 (419 women) patients, 311 had both APS and CCCS measured. Average MRP was 51 mmHg (SD 23.2 mmHg) for men and 39 mmHg (19.2 mmHg) for women. Functional ACL was 1.7 cm for men and 0.7 cm for women. Univariate analyses demonstrated significant associations between CCCS and MRP (P = 0.0002), ACL (P = 0.0006) and pudendal neuropathy (P < 0.0001). The association between APS and CCCS was significant (P < 0.0001) but accounted for only 9.2% of the variability in CCCS. Multiple regression showed that the variables most useful in predicting CCCS were external sphincter defect, pudendal neuropathy and previous pelvic surgery, but only improving the scores predictive ability to 12.5%.

CONCLUSION

This study shows that the ability of AP tests to predict continence scores improves when considered collectively, but that a constructed summation model before and after multiple regression is poor at predicting the variability in continence scores.

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.

Evaluation of vector manometry for characterization of functional outcome after restorative proctocolectomy

AIM

The impact of 3-dimensional vector manometry (VM) for characterization of the functional outcome of restorative proctocolectomy (RP) was studied in 61 patients at a median of 86 months after RP for ulcerative colitis.

METHODS

A 14-day continence diary was utilized to quantify continence, urgency, and the frequency of defecation. The clinical outcome data were correlated to the physiology parameters of VM and volumetry.

RESULTS

VM parameters at rest correlated with postoperative continence but not substantially with stool frequency and urgency. High radial asymmetry was significantly correlated with the degree of incontinence (r=0.333, p=0.013). Resting pressures demonstrated a better correlation with the degree of incontinence when documented for the high-pressure zone (HPZ; portion of the sphincter with at least 50% of the maximum pressure; r=0.301, p=0.025) and when performed in the continuous pull-through technique. Stool frequency and urgency were better characterized by volumetry parameters like threshold volumes and pouch compliance. The specificity and sensitivity of the vector volume at rest of the HPZ for the prediction of incontinence was 63.6% and 59.1%, respectively. The corresponding values were 67% and 68%, respectively, for radial asymmetry at rest. Stool frequency and urgency were better characterized by volumetry parameters like threshold volumes and pouch compliance.

CONCLUSION

A strong anal sphincter at rest and a consistent radial distribution of the sphincter pressure are the most reliable indicators of continence after RP obtained by VM, but their clinical usefulness is limited.

The longitudinal high-pressure zone profile in patients with fecal incontinence

OBJECTIVE

The aim of this study was to evaluate differences in the longitudinal high-pressure zone (HPZ) profile between incontinent patients and healthy controls.

METHODS

One hundred and fifty-six patients with fecal incontinence (mean age 63 yr; 139 women, 17 men) and 25 healthy controls (mean age 54 yr; 20 women, five men) underwent anorectal manometry with a perfused catheter using a station pull-through technique.

RESULTS

Maximum resting pressure (MRP) and maximum squeeze pressure (MSP) were lower in patients (p < 0.001) and the HPZ was shorter in patients (p < 0.05). The ratio MRP/sum of resting pressures within HPZ did not differ between the groups. The severity of incontinence measured as an incontinence score was correlated to MSP (p < 0.05) and sum of squeeze pressure within HPZ (p < 0.05), but not to any other variable. The relative pressure amount during rest in the distal half of HPZ was higher in controls (63% vs 56%, p < 0.05), but this was not seen during squeeze.

CONCLUSIONS

These results suggest that the main difference between incontinent patients and healthy controls is a greater magnitude of the pressure profile in the latter group. Furthermore, the relative pressure accumulation during rest tended to be more distally located within the HPZ.

Recovery of anal sphincter function after the ileoanal reservoir procedure in patients over the age of fifty

PURPOSE

This study was undertaken to postoperatively assess the progression of anal sphincter function and clinical outcome in patients > or = 50 years old (Group I) compared with those < 50 years old (Group II).

METHODS

Clinical data were assessed after ileostomy closure by a questionnaire. These data were compiled to obtain an incontinence score, which ranged from 0 (perfect continence) to 20 (total incontinence). Anorectal manometry was performed preoperatively (MN1) and postoperatively, before (MN2) and after (MN3) ileostomy closure. Wilcoxon and paired t-test were used to compare the clinical and functional results, respectively.

RESULTS

Group I consisted of 22 patients (mean age, 56 years) and Group II, 50 patients (mean age, 32 years). No differences were found relative to either preoperative pressures or clinical outcome. However, both the mean and high resting pressures were significantly lower in Group I at the MN2 examination.

CONCLUSION

The effect on anal sphincters of ileoanal reservoir in patients over the age of 50 years is similar to that noted in younger patients. Transient impairment of internal anal sphincter function observed after ileoanal reservoir is more severe in older patients (P = 0.01). However, as in younger patients, it does completely recover after ileostomy closure.