Vector volume manometry--methods and normal values

High-resolution anal manometry: Repeatability, validation, and comparison with conventional manometry

BACKGROUND

Accurate measurement of anal sphincter function is potentially of value in defining treatment of common pelvic floor disorders. The aim of this study was to establish repeatability and validate high-resolution anorectal manometry (HRAM) by comparison to conventional manometry (CM). Arising from this work would be definitive normal range data.

METHODS

Eighty healthy volunteers (40 female) underwent a test-retest repeatability study. A 16-channel water-perfused HRAM catheter was compared to an 8-channel conventional catheter using a station pull-through technique.

KEY RESULTS

High-resolution anorectal manometry had similar precision to conventional manometry when measuring resting pressure (intraclass correlation coefficient [ICC] 0.73 vs 0.68, HRAM vs CM) and squeeze increment (ICC 0.90 vs 0.94, HRAM vs CM). HRAM measured resting pressures 10% lower than CM and squeeze pressure 27% higher than CM.

CONCLUSIONS AND INFERENCES

High-resolution anorectal manometry is a valid technique with comparable precision to CM. HRAM measurements differ considerably to CM, and a new set of normal values must be used.

Resting vector volume measured before ileostomy reversal may be a predictor of major fecal incontinence in patients with mid or low rectal cancer: a longitudinal cohort study using a prospective clinical database

PURPOSE

Despite a high incidence of fecal incontinence following sphincter-preservation surgery (SPS), there are no definitive factors measured before ileostomy reversal that predict fecal incontinence. We investigated whether vector volume anorectal manometry before ileostomy reversal predicts major fecal incontinence following SPS in patients with mid or low rectal cancer.

METHODS

This longitudinal prospective cohort study comprised 173 patients who underwent vector volume anorectal manometry before ileostomy reversal. The Fecal Incontinence Severity Index was measured 1 year after the primary SPS and classified as major incontinence (FISI score ≥ 25) or continent/minor incontinence (FISI score < 25). Multivariable logistic regression analysis was used to identify predictors of major incontinence.

RESULTS

Ninety-two patients (53.1%) had major incontinence. Although tumor stage, location, and neoadjuvant chemoradiotherapy were comparable, the major incontinence group had lower resting pressure (28.4 vs. 34.3 mmHg, P = 0.027), greater asymmetry at rest (39.1% vs. 34.1%, P = 0.002) and squeezing (34.2% vs. 31.4%, P = 0.046), shorter sphincter length (3.3 vs. 3.7 cm, P = 0.034), and lower resting vector volume (143,601 vs. 278,922 mmHg² mm, P < 0.001) compared with the continent/minor incontinence group. Resting vector volume was the only independent predictor of major incontinence (odds ratio = 0.675 per 100,000 mmHg² mm, 95% confidence interval, 0.532-0.823; P = 0.006).

CONCLUSIONS

This study revealed that resting vector volume before ileostomy reversal may predict major fecal incontinence. We suggest that the physiology of the anorectum should be discussed with patients before ileostomy reversal in patients at high risk of fecal incontinence.

Synchronized functional anal sphincter assessment: maximizing the potential of anal vector manometry and 3-D anal endosonography

BACKGROUND

Understanding the association between structure and function is vital before considering surgery involving anal sphincter division. By correlating three-dimensional anal endosonography (AES) and three-dimensional anal canal vector volume manometry (VVM), this study details a method to produce measurements of both sphincter length and pressure leading to identification of the functionally important areas of the anal canal. The aim of this study was to provide combined detailed information on anal canal anatomy and physiology.

METHODS

Twelve males and 12 nulliparous females with no bowel symptoms underwent VVM (using a water-perfused, eight-channel radially arranged catheter) and AES.

KEY RESULTS

The synchronization of AES and VVM identified that the majority of rest and squeeze anal pressure is present in the portion of the anal canal covered by both anal sphincters. Nearly, 20% of overall resting anal pressure is produced distal to the caudal termination of the internal anal sphincter. Puborectalis accounts for a significantly greater percentage volume of pressure in females both at rest and when squeezing, though the total volume of pressure is not significantly greater.

CONCLUSIONS AND INFERENCES

The majority of resting and squeezing pressure and the least asymmetry, in both sexes, is in the portion of the anal canal covered by external anal sphincter. In females, the external anal sphincter is shorter and a proportionately longer puborectalis accounts for a greater percentage of pressure. Sphincter targeted fistula surgery in females must be performed with special caution. A protective role for puborectalis following obstetric anal sphincter injury is suggested.

3D high-definition manometry in evaluation of children after surgery for Hirschsprung's disease: A pilot study

PURPOSE

Anorectal 3-dimensional high definition manometry (3D HRM) could be the best tool for postoperative assessment of restorative surgical procedures for Hirschsprung's disease. The aim of our study was to evaluate patients after surgery for Hirschsprung's disease using 3D HRM.

MATERIALS AND METHODS

Anorectal function was evaluated using solid state 3D HRM. We measured the length of the anal canal, mean resting squeeze pressures, the presence of rectoanal inhibitory reflex, cough reflex, ano-anal reflex and the bear down manoeuvre.

RESULTS

We studied 14 children operated on for Hirschsprung's disease. The mean values of pressure asymmetry were higher in patients after the Duhamel procedure than after the TEPT procedure (29.58% vs. 22.26% during resting and 26.1% vs. 14.01% during squeeze, respectively). No difference between the groups was observed in the measurement of all the manometric parameters except the presence of rectoanal inhibitory reflex (87.5% after TEPT vs. 33% after Duhamel).

CONCLUSIONS

Anorectal 3D HRM evaluation of patients with Hirschsprung's disease demonstrated that the asymmetry of the anal canal occurred in a similar percentage after both procedures.