Continuous vs stepwise anal acoustic reflectometry: An improved technique for physiological measurement of anal sphincter function?

BACKGROUND: Anal acoustic reflectometry (AAR) is a technique for measuring the physiological profile of the anal canal, primarily the internal anal sphincter. Evaluation of a new continuous method, recently developed for the urethra, would enable its future application for investigation of rectal reflexes. METHODS: Patients aged 18 and over with fecal incontinence (FI) were included. Stepwise AAR parameters were compared with continuous opening pressure (Op, cmH2 O), opening elastance (Oe, cmH2 O/mm2 ), closing pressure (Cp, cmH2 O), closing elastance (Ce, cmH2 O/mm2 ), hysteresis (Hys, [%]), squeeze opening pressure (SqOp, cmH2 O), and squeeze opening elastance (SqOe, cmH2 O/mm2 ). Vaizey incontinence and Manchester Health Questionnaire scores were also collected. RESULTS: Thirty-two patients, 26 females were analyzed. Median age: 60 (range, 32-75). Median AAR parameters of Op (37.50 vs 35.15, P = .031), Oe (1.31 vs 0.84, P < .0001), Ce (1.11 vs 0.88, P < .0001), Hys (37.75 vs 19.04, P < .0001), and SqOe (1.27 vs 1.06, P = .005) were significantly higher with the continuous method. Cp (22.70 vs 27.22, P = .003) is lower and SqOp (96.87 vs 59.47, P = .71) not significantly different. The continuous technique had superior repeatability between cycles for all AAR parameters except Oe, which was equivalent and continuous SqOp had a stronger negative correlation with Vaizey score than stepwise (-0.46, P = .009 vs -0.37, P = .038). CONCLUSIONS: The differences seen between the two techniques are likely to be related to the rate of stretch. The continuous technique appears to represent a more physiological measurement of anal sphincter function than the stepwise technique particularly in the assessment of voluntary squeeze function.

Methodologic Validation of a Faster Pelvic Floor Test: Two Randomized Studies in Anal Acoustic Reflectometry.

BACKGROUND: Anal acoustic reflectometry investigates the opening and closing function of the anal canal using reflected sound waves to measure a cross-sectional area at different pressures. Anal acoustic reflectometry is reliable and repeatable, distinguishes between continence and incontinence and between subgroups of incontinence, correlates with symptom severity, and does not distort the anal canal during investigation. OBJECTIVE: The purpose of this study was to validate anal acoustic reflectometry methodology by asking 2 questions: can anal acoustic reflectometry be used alongside manometry (order study) and can anal acoustic reflectometry be performed faster (filling study). The secondary aim was to assess the response of the anal canal to stretch using anal acoustic reflectometry. DESIGN: This research included 2 prospective randomized studies. SETTINGS: The study was conducted at a tertiary referral center. PATIENTS: Patients undergoing investigation for fecal incontinence were included. INTERVENTION: For the order study, patients were prospectively randomized to anal acoustic reflectometry, manometry, 2-minute rest and then manometry, anal acoustic reflectometry, or vice versa. For the filling study, patients were prospectively randomized to fast rate anal acoustic reflectometry (5 cm H2O/1 s), manometry, 2-minute rest and then manometry, normal rate anal acoustic reflectometry (5 cm H2O/3 s), or vice versa. MAIN OUTCOME MEASURES: The primary outcome was no difference in anal acoustic reflectometry or manometry variables. Demographic and clinical data were recorded. RESULTS: The order study included 30 patients with a median age of 63 years (range, 30-84 y); 77% were women. No difference was found among all of the variables of anal acoustic reflectometry and manometry regardless of which test was performed first. The filling study included 50 patients with a median age of 62 years (range, 30-78 y); 80% were women. No difference was found between fast and normal rates of anal acoustic reflectometry and manometry in any order. LIMITATIONS: This study was limited by its comparison with water-perfused manometry. CONCLUSIONS: Anal acoustic reflectometry and manometry can be performed at the normal or fast rate of anal acoustic reflectometry in any order. A fast rate of anal acoustic reflectometry did not augment the response of the anal canal to stretch as measured by anal acoustic reflectometry and manometry. This study validates a faster anal acoustic reflectometry technique and vindicates previous data. See Video Abstract at http://links.lww.com/DCR/A821.

The short-term effects of posterior tibial nerve stimulation on anorectal physiology in patients with faecal incontinence: a single centre experience.

BACKGROUND: Posterior tibial nerve stimulation (PTNS) is a novel treatment for patients with faecal incontinence (FI) and may be effective in selected patients; however, its mechanism of action is unknown. We sought to determine the effects of PTNS on anorectal physiological parameters. METHODS: Fifty patients with FI underwent 30 min of PTNS treatment, weekly for 12 weeks. High-resolution anorectal manometry, bowel diaries and Vaizey questionnaires were performed before and after treatment. Successful treatment was determined as a greater than 50% reduction in FI episodes. RESULTS: Fifty patients with FI were studied; 39 women, median age 62 years (range 30-82). Compared with pretreatment, there were reductions in episodes of urgency (16.0 versus 11.4, p = 0.006), overall FI (14.5 versus 9.1, p = 0.001), urge FI (5.4 versus 3.2, p = 0.016) and passive FI (9.1 versus 5.9, p = 0.008). Vaizey score was reduced (16.1 versus 14.5, p = 0.002). Rectal sensory volumes (ml) decreased (onset 40.3 versus 32.6, p = 0.014, call 75.7 versus 57.5, p < 0.001, urge 104.1 versus 87.4, p = 0.004). There was no significant change in anal canal pressures (mmHg) (maximum resting pressure 41.4 versus 44.2, p = 0.39, maximum squeeze pressure, 78.7 versus 88.2, p = 0.15, incremental squeeze pressure 37.2 versus 44.1, p = 0.22). Reduction in FI episodes did not correlate with changes in physiological parameters (p > 0.05). Treatment success of 44% was independent of changes in manometric parameters (p > 0.05). CONCLUSIONS: PTNS has a measureable physiological effect on rectal sensory volumes without an effect on anal canal pressures. It also reduces FI episodes; however, this effect is independent of changing physiology, suggesting that PTNS has a complex mechanism of action.

Use of Anal Acoustic Reflectometry in the Evaluation of Men With Passive Fecal Leakage.

BACKGROUND: Men with passive fecal leakage represent a distinct clinical entity in which the pathophysiology remains unclear. Standard anorectal investigations fail to demonstrate consistent abnormalities in this group. Anal acoustic reflectometry is a new test of anal sphincter function with greater sensitivity and discriminatory ability than conventional anal manometry. OBJECTIVE: The aim of this study was to determine whether men with fecal leakage have an abnormality in anal sphincter function that is detectable by anal acoustic reflectometry. DESIGN: This was an age-matched study of continent and incontinent men. SETTINGS: The study was conducted at a university teaching hospital. PATIENTS: Male patients with isolated symptoms of fecal leakage were recruited. Anal acoustic reflectometry, followed by conventional anal manometry, was performed. Results were then compared with those from an age-matched group of men with no symptoms of anal incontinence or anorectal pathology. MAIN OUTCOME MEASURES: Variables measured with anal acoustic reflectometry and anal manometry in the incontinent and continent men were compared. RESULTS: Thirty subjects were recruited, of whom 15 were men with fecal leakage and 15 were continent men. There was a significantly higher incidence of previous anorectal surgery in the men with leakage. The anal acoustic reflectometry variables of opening and closing pressure were significantly lower in leakers compared with continent subjects (p = 0.003 and p = 0.001). Hysteresis was significantly greater in the male leaker group (p = 0.026). No difference was seen in anal manometry. LIMITATIONS: With a larger sample size, the effect of previous anorectal surgery and the presence of an anal sphincter defect could be clarified. CONCLUSIONS: Anal acoustic reflectometry is a sensitive test of anal sphincter function and, unlike anal manometry, can discriminate male leakers from continent subjects. An identifiable abnormality has been detected using anal acoustic reflectometry, which may further our understanding of the pathogenesis in this group.

Complete circumferential rectal ulceration and haemorrhage secondary to the use of a faecal management system.

This structured case report is a brief case report describing an episode of complete circumferential rectal ulceration and haemorrhage secondary to the use of a faecal management system. An elderly lady was admitted for elective cardiac surgery. Prior to admission, the patient was taking warfarin in view of her atrial fibrillation. Following surgery, the patient developed faecal incontinence, which was managed with a faecal management system. However, the patient subsequently developed massive rectal haemorrhage from an area of complete circumferential ulceration in the rectum. This ulceration resulted from pressure necrosis secondary to the faecal management system balloon placed in the patient's rectum. The implication for care is that faecal management systems are an important adjunct in the management of faecal incontinence, but caution must be exercised with prolonged use, particularly in anticoagulated patients.

Viscoelastic assessment of anal canal function using acoustic reflectometry: a clinically useful technique.

BACKGROUND: Anal acoustic reflectometry is a new reproducible technique that allows a viscoelastic assessment of anal canal function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, opening and closing elastance, and hysteresis. OBJECTIVE: The aim of this study was to assess whether the parameters measured in anal acoustic reflectometry are clinically valid between continent and fecally incontinent subjects. DESIGN: This was an age- and sex-matched study of continent and incontinent women. SETTING: The study was conducted at a university teaching hospital. PATIENTS: One hundred women (50 with fecal incontinence and 50 with normal bowel control) were included in the study. Subjects were age matched to within 5 years. MAIN OUTCOME MEASURES: Parameters measured with anal acoustic reflectometry and manometry were compared between incontinent and continent groups using a paired t test. Diagnostic accuracy was assessed by the use of receiver operator characteristic curves. RESULTS: Four of the 5 anal acoustic reflectometry parameters at rest were significantly different between continent and incontinent women (eg, opening pressure in fecally incontinent subjects was 31.6 vs 51.5 cm H2O in continent subjects, p = 0.0001). Both anal acoustic reflectometry parameters of squeeze opening pressure and squeeze opening elastance were significantly reduced in the incontinent women compared with continent women (50 vs 99.1 cm H2O, p = 0.0001 and 1.48 vs 1.83 cm H2O/mm, p = 0.012). In terms of diagnostic accuracy, opening pressure at rest measured by reflectometry was significantly superior in discriminating between continent and incontinent women in comparison with resting pressure measured with manometry (p = 0.009). CONCLUSIONS: Anal acoustic reflectometry is a new, clinically valid technique in the assessment of continent and incontinent subjects. This technique, which assesses the response of the anal canal to distension and relaxation, provides a detailed viscoelastic assessment of anal canal function. This technique may not only aid the investigation of fecally incontinent subjects, but it may also improve our understanding of anal canal physiology during both the process of defecation and maintenance of continence.

Anal acoustic reflectometry: a new reproducible technique providing physiological assessment of anal sphincter function.

BACKGROUND: Anal acoustic reflectometry is a new technique of assessing anal sphincter function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, the opening and closing elastance, and hysteresis. OBJECTIVE: This study aimed to compare the reproducibility of this new technique, in terms of test-retest and interrater reliability, with manometry, the current standard test of sphincter function. DESIGN: This is a comparative study of reproducibility between anal acoustic reflectometry and manometry. SETTINGS: This study was conducted at a university hospital (outpatient clinic and endoscopy unit). PATIENTS: Twenty-six (21 female) subjects were assessed with both anal acoustic reflectometry and manometry on 2 separate occasions (test-retest reliability) and 22 (16 female) subjects were assessed with both methods by 2 separate investigators (interrater reliability). MAIN OUTCOME MEASURES: Reproducibility was assessed according to the Bland-Altman method. RESULTS: All of the measured novel anal acoustic reflectometry parameters had acceptable mean differences and repeatability coefficients. Comparison of the 2 methods of sphincter assessment (anal acoustic reflectometry vs manometry) was made for measurements taken at rest and during voluntary contraction. There was no significant difference in terms of test-retest reliability between the manometry maximum resting pressure vs the reflectometry opening pressure (P = .57) or manometry maximum squeeze pressure vs the reflectometry squeeze opening pressure (P = .68). No significant difference between methods was found in interrater reliability during assessments at rest (P = .62) and voluntary contraction (P = .96). LIMITATIONS: Anal acoustic reflectometry is limited, as with all tests of anorectal function, in that the device is placed within the anal canal, causing stimulation of sensory and stretch receptors. CONCLUSIONS: Anal acoustic reflectometry has a reproducibility comparable to manometry in terms of both test-retest and interrater reliability. Anal acoustic reflectometry is a promising technique that allows an assessment of anal canal physiology that is not available with manometry.

Anterior anal sphincter repair can be of long term benefit: a 12-year case cohort from a single surgeon.

BACKGROUND: Early surgical results of anterior sphincter repair for faecal incontinence can be good, but in the longer term are often disappointing. This study aimed to determine the short and long term outcomes from anterior sphincter repair and identify factors predictive of long term success. METHODS: Patients who underwent anterior sphincter repair between 1989 and 2001 in one institution were identified. Postal questionnaires were sent to patients, which included validated scoring systems for symptom severity and quality of life assessments for faecal incontinence. Patient demographics and risk factors were recorded as were the results of anorectal physiology studies and endoanal ultrasound. RESULTS: Eighty-five patients underwent repair by one consultant. The length of follow up ranged from 1 to 12 years. Most patients (96%) had early symptom improvement postoperatively. Of the 47 patients assessed long term (> or = 5 years), 28 (60%) maintained this success. Significant improvements in quality of life were observed (P < 0.001). Neither patient, surgical nor anorectal physiology study parameters were predictive of outcome. CONCLUSION: There were no predictive factors of outcome success and no changes in anal manometry identified, however anterior sphincter repair remains worthwhile. Changes in compliance of the anorectum may be responsible for symptom improvement.