Functional Anal Canal Length Research Articles

Effects on anorectal function of endoscopic submucosal dissection for rectal tumors involving the dentate line.

Endoscopic submucosal dissection (ESD) is a specific procedure that uses an electrosurgical knife for en-bloc resectioning large tumors. However, no study has examined the effect of ESD on the defecation function of patients with rectal tumors. We aimed to investigate the potential effects caused by ESD by analyzing changes in the morphology and movement of the anorectum pre- and post-ESD. This prospective observational study included 11 patients with anorectal tumors who underwent ESD between April 2020 and February 2022. Pre-ESD assessments included anorectal manometry and defecography. Post-ESD assessments were conducted 2 months later, including anorectal manometry, defecography, and proctoscopy for ulcer and stenosis evaluation. The median patient age was 73 years, including seven males and four females. Eight patients (73%) had a tumor in the lower rectum, and the extent of resection was less than 50% of the rectal lumen. Resection reached the dentate line in six cases (55%). In the patients with post-ESD mucosal defects involving the dentate line, the median of functional anal canal length significantly decreased from (3.4 cm pre-ESD to 2.8 cm post-ESD, p = 0.04). Defecography revealed one case with incomplete evacuation (<50%) and incontinence post-ESD. Interestingly, patients with pre-existing rectoceles noted resolution of lesions post-ESD. None of the patients reported daily constipation or fecal incontinence. While rectal ESD is unlikely to cause significant real-world defecation difficulties, alterations in rectal and anal canal morphology and function may occur if the dentate line is involved in the resection range.

London Protocol under water-perfused HRM in a healthy population, towards novel 3D manometric parameters in an evaluation of anorectal functional disorders

Background/AimLondon Protocol (LP) and Classification allied to high-resolution manometry (HRM) technological evolution has updated and enhanced the diagnostic armamentarium in anorectal disorders. This study aims to evaluate LP reproducibility under water-perfused HRM, provide normal data and new parameters based on 3D and healthy comparison studies under perfusional HRM.MethodsFifty healthy (25 F) underwent water-perfused 36 channel HRM based on LP at resting, squeeze, cough, push, and rectal sensory. Additional 3D manometric parameters were: pressure-volume (PV) 104mmHg2.cm (resting, short and long squeeze, cough); highest and lowest pressure asymmetry (resting, short squeeze, and cough). Complementary parameters (CP) were: resting (mean pressure, functional anal canal length); short squeeze (mean and maximum absolute squeeze pressure), endurance (fatigue rate, fatigue rate index, capacity to sustain); cough (anorectal gradient pressure); push (rectum-anal gradient pressure, anal canal relaxation percent); recto-anal inhibitory reflex (anal canal relaxation percent).ResultsNo difference to genders: resting (LP, CP, and 3D); short squeeze (highest pressure asymmetry); endurance (CP); cough (CP, highest and lowest pressure asymmetry); push (gradient pressure); rectal sensory. Higher pressure in men: short squeeze (maximum incremental, absolute, and mean pressure, PV, lowest pressure asymmetry); long squeeze (PV); cough (anal canal and rectum maximum pressure, anal canal PV); push (anal canal and rectum maximum pressure). Anal canal relaxation was higher in women (push).ConclusionsLP reproducibility is feasible under water-perfused HRM, and comparative studies could bring similarity to dataset expansion. Novel 3D parameters need further studies with healthy and larger data to be validated and for disease comparisons.Key points• London Protocol and Classification allied with the technological evolution of HRM (software and probes) has refined the diagnostic armamentarium in anorectal disorders.• Novel 3D and deepening the analysis of manometric parameters before the London Classification as a contributory diagnostic tool.• Comparison of healthy volunteers according to the London Protocol under a perfusional high-resolution system could establish equivalence points.

Results of surgical treatment of anal sphincter injury following vaginal delivery at Hanoi Medical University Hospital: a case series report

The repair of sphincter injury following vaginal delivery is often inadequate or the injury was undetected. The consequence is fecal incontinence. In this descriptive study, five patients underwent sphincter repair by the “overlap” technique. Evaluation of postoperative outcomes at 3 and 12 months showed that the Wexner fecal incontinence score at 17 - 20 score decreased to 0 - 6 score. Transperineal ultrasound showed that all five patients healed well. Measurement of anal manometry, functional anal canal length, resting anal pressures and squeezing anal pressures was better after surgery.

Normal values for high-resolution anorectal manometry in healthy young adults: evidence from Vietnam

BackgroundHigh-resolution anorectal manometry (HRAM) has been developed to improve measurement of anorectal functions. This study aims to identify normal HRAM values in healthy young Vietnamese adults.Methods We conducted a cross-sectional study at the National Hospital of Traditional Medicine (Hanoi, Vietnam) from July through December 2014. Healthy young adults were invited to participate in the study. All anorectal measurement values were performed using the ISOLAB high-resolution manometry system. Differences between groups were analyzed using Student’s t-tests.ResultsThirty healthy young adults, including 15 males and 15 females aged 19–26 years, were recruited. Mean functional anal canal length was 3.4 ± 0.5 cm (range: 2.4–4.8 mm). Mean maximum resting pressure, mean maximum squeezing pressure, mean maximum coughing pressure, and mean maximum strain pressure were 65.5, 168.0, 125.9, and 84.2 mm Hg, respectively. All anal pressure values were significantly different between males and females. For rectal sensation measurements, only the volume at first sensation was significantly higher in males than in females.ConclusionsThis study provides normal HRAM value for healthy young adults in Vietnam. Sex may influence anal pressure and first rectal sensation values in this cohort. Further studies should be conducted in order to improve the quality of HRAM normal values and to confirm the effects of sex.

Effect of High Suspension and Low Incision Surgery Based on Traditional Ligation of Chinese Medicine in Treatment of Mixed Haemorrhoids: A Multi-centre, Randomized, Single-Blind, Non-inferiority Clinical Trial.

To observe the clinical effect of high suspension and low incision (HSLI) surgery on mixed haemorrhoids, compared with Milligan-Morgan haemorrhoidectomy. A multi-centre, randomized, single-blind, non-inferiority clinical trial was performed. Participants with mixed haemorrhoids from Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing Rectum Hospital, Air Force Medical Center of People's Liberation Army of China, and Puyang Hospital of Traditional Chinese Medicine were enrolled from September 2016 to March 2018. By using a blocked randomization scheme, participants were assigned to two groups. The experimental group was treated with HSLI, while the control group was treated with Milligan-Morgan haemorrhoidectomy. The primary outcome was the clinical effect evaluated at 12 weeks after operation. The secondary outcomes included the number of haemorrhoids treated during the operation, pain scores, use of analgesics, postoperative oedema, wound healing, incidence of anal stenosis, anorectal manometry after operation, as well as surgical duration, length of stay and total hospitalization expenses. A safety evaluation was also conducted. In total, 246 eligible participants were enrolled, with 123 cases in each group. There was no significant difference in the clinical effect between the two groups (100.00% vs. 99.19%, P>0.05). Compared with the control group, the number of external haemorrhoids treated during the operation and the pain scores after operation were significantly reduced in the experimental group (P<0.05 or P<0.01); the patient number with wound healing at 2 weeks after operation and the functional length of anal canal at 12 weeks after operation were significantly increased in the experimental group (P<0.05). There was no significant difference in the incidence of anal stenosis, the numbers of patients using analgesics and patients with postoperative oedema between the two groups after operation (P>0.05). The surgical duration and length of stay in the experimental group were significantly longer than those in the control group, and the total hospitalization expense was significantly higher than that in the control group (all P<0.05). No adverse events were reported in either group during the whole trial or follow-up period. HSLI had the advantages of preserving the skin of anal canal completely, alleviating postsurgical pain and promoting rapid recovery after operation. (Registration No. ChiCTR1900022883).

Normal Values and Associated Factors in High-resolution Anorectal Manometry in Healthy Vietnamese Adults

Abstract Introduction The present study aims to identify normal high-resolution anorectal manometry (HRAM) values and related factors in healthy Vietnamese adults. Methods The present cross-sectional study was conducted at the Viet Duc hospital, Hanoi, Vietnam, during April and May 2019. Healthy volunteers were recruited to participate in the study. Anorectal measurement values from the digestive tract, including pressure, were recorded. Results A total of 76 healthy volunteers were recruited. The mean functional anal canal length was 4.2 ± 0.5 cm, while the mean anal high-pressure zone length was 3.4 ± 0.5 cm. The mean defecation index was 1.4 ± 0.8, with values ranging from 0.3 to 5.0. The mean threshold volume to elicit the rectoanal inhibitory reflex (RAIR) was 18.1 mL. The mean rectal sensation values were 32.4 mL, 81.6 mL, and 159 mL for first sensation, desire to defecate, and urge to defecate, respectively. Dyssynergic patterns occurred in ∼ 50% of the study participants and included mainly types I (27.6%) and III (14.6%). There were significant differences between male and female patients in terms of maximum anal squeeze pressure, maximum anal cough pressure, maximum anal strain pressure, maximum rectal cough pressure, and maximum rectal strain pressure (all p &lt; 0.01). Conclusions The present study establishes normal HRAM values in healthy Vietnamese adults, particularly regarding normal values of anorectal pressure and rectal sensation. Further studies that include larger sample sizes should be conducted to further confirm the constants and their relationships.

Functional anal canal length measurement using high-resolution anorectal manometry to investigate anal sphincter dysfunction in patients with fecal incontinence or constipation.

Using high-resolution anorectal manometry, we aimed to evaluate the: (a) optimal threshold to measure functional anal canal length (FACL) with intra- and inter-observer variability; (b) relationship between abnormal FACL and other phenotypic findings; and (c) utility of FACL measurement to discriminate between healthy volunteers (HV) and patients with fecal incontinence (FI) or chronic constipation (CC). Consecutive patients referred for investigation of FI or CC in isolation were included. FACL was calculated at 5, 10, 20, 30, and 50mm Hg above rectal pressure. 5th-95th percentile in HV defined limits of normality. FACL was analyzed in 192 patients with FI (154 females), 204 patients with CC (175 females), and 134 HV (101 females). The optimal threshold for measurement of FACL was 20mm Hg. Using this threshold, observer reproducibility was very high (ICC 0.99, P<0.0001). FACL was shorter in females with FI and longer in females with CC compared to HV (2.3 vs 2.9cm; and 3.4cm vs 2.9cm; both P<0.0001). Twenty percent of females and 13% males with FI had a short FACL, associated with older age, anal hypotonia or hypocontractility, and a atrophic internal anal sphincter. However, abnormal FACL in isolation was only found in 1/190 FI (0.5%) and 2/201 CC (1%) patients; all other patients had other abnormal manometric findings. Considering overlap with other routinely evaluated manometric parameters, FACL measurement does not provide additional information in the diagnostic assessment of FI or CC.

Randomized clinical trial of transcutaneous electrical posterior tibial nerve stimulation versus lateral internal sphincterotomy for treatment of chronic anal fissure

ObjectivesThe objective of this study was to evaluate the efficacy of transcutaneous electrical posterior tibial nerve stimulation in treatment of patients with chronic anal fissure and to compare it with the conventional lateral internal sphincterotomy. Patients and methodsConsecutive patients with chronic anal fissure were randomly allocated into two treatment groups: transcutaneous electrical posterior tibial nerve stimulation group and lateral internal sphincterotomy group. The primary outcome measures were number of patients with clinical improvement and healed fissure. Secondary outcome measures were complications, VAS pain scores, Wexner's constipation and Peascatori anal incontinence scores, anorectal manometry, and quality of life index. ResultsSeventy-three patients were randomized into two groups of 36 patients who were subjected to transcutaneous electrical nerve stimulation and 37 patients who underwent lateral internal sphincterotomy. All (100%) patients in lateral internal sphincterotomy group had clinical improvement at one month following the procedure in contrast to 27 (75%) patients in transcutaneous electrical nerve stimulation group. Recurrence of anal fissure after one year was reported in one (2.7%) and 11 (40.7%) patients in lateral internal sphincterotomy and transcutaneous electrical nerve stimulation groups respectively. Resting anal pressure and functional anal canal length were significantly reduced after lateral internal sphincterotomy. ConclusionTranscutaneous electrical posterior tibial nerve stimulation for treatment of chronic anal fissure is a novel, non-invasive procedure and has no complications. However, given the higher rate of clinical improvement and fissure healing and the lower rate of fissure recurrence, lateral internal sphincterotomy remains the gold standard for treating chronic anal fissure.

Anorectal manometry with and without ketamine for evaluation of defecation disorders in children

IntroductionAnorectal manometry (ARCM) provides valuable information in children with chronic constipation and fecal incontinence but may not be tolerated in the awake child. This study aimed to evaluate the effect of ketamine anesthesia on the assessment of anorectal function by manometry and to evaluate defecation dynamics and anal sphincter resting pressure in the context of pathophysiology of chronic functional (idiopathic) constipation and soiling in children. MethodsThis was a prospective study of children who were investigated for symptoms of chronic constipation and soiling between April 2001 and April 2004. We studied 52 consecutive children who had awake ARCM, biofeedback training and endosonography (awake group) and 64 children who had ketamine anesthesia for ARCM and endosonography (ketamine group). We age matched 31 children who had awake anorectal studies with 27 who had ketamine anesthesia. ResultsThe children in awake and ketamine groups were comparable for age, duration of bowel symptoms and duration of laxative treatments. ARCM profile was comparable between the awake and the ketamine groups with regard to anal sphincter resting pressure, rectal capacity, amplitude of rectal contractions, frequency of rectal and IAS contractions and functional length of anal canal. Of 52 children who had awake ARCM, dyssynergia of the EAS muscles was observed in 22 (42%) and median squeeze pressure was 87mm Hg (range 25–134). The anal sphincter resting pressure was non-obstructive and comparable to healthy normal children. Rectoanal inhibitory reflex was seen in all children excluding diagnosis of Hirschsprung disease. ConclusionsKetamine anesthesia does not affect quantitative or qualitative measurements of autonomic anorectal function and can be used reliably in children who will not tolerate the manometry while awake. Paradoxical contraction of the EAS can only be evaluated in the awake children and should be investigated further as the underlying cause of obstructive defecation in patients with chronic functional constipation and soiling.

Traditional measures of normal anal sphincter function using high‐resolution anorectal manometry (HRAM) in 115 healthy volunteers

High-resolution anorectal manometry (HRAM) is a relatively new method for collection and interpretation of data relevant to sphincteric function, and for the first time allows a global appreciation of the anorectum as a functional unit. Historically, traditional anal manometry has been plagued by lack of standardization and healthy volunteer data of variable quality. The aims of this study were: (i) to obtain normative data sets for traditional measures of anorectal function using HRAM in healthy subjects and; (ii) to qualitatively describe novel physiological phenomena, which may be of future relevance when this method is applied to patients. 115 healthy subjects (96 female) underwent HRAM using a 10 channel, 12F solid-state catheter. Measurements were performed during rest, squeeze, cough, and simulated defecation (push). Data were displayed as color contour plots and analysed using a commercially available manometric system (Solar GI HRM v9.1, Medical Measurement Systems). Associations between age, gender and parity were subsequently explored. HRAM color contour plots provided clear delineation of the high-pressure zone within the anal canal and showed recruitment during maneuvers that altered intra-anal pressures. Automated analysis produced quantitative data, which have been presented on the basis of gender and parity due to the effect of these covariates on some sphincter functions. In line with traditional manometry, some age and gender differences were seen. Males had a greater functional anal canal length and anal pressures during the cough maneuver. Parity in females was associated with reduced squeeze increments. The study provides a large healthy volunteer dataset and parameters of traditional measures of anorectal function. A number of novel phenomena are appreciated, the significance of which will require further analysis and comparisons with patient populations.

Non-sphincter splitting fistulectomy vs conventional fistulotomy for high trans-sphincteric fistula-in-ano: a prospective functional and manometric study

This study compared the clinical and physiological results of non-sphincter splitting fistulectomy (N-SSF) with those of sphincter splitting fistulotomy (SSF) for treatment of high trans-sphincteric fistula-in-ano. A prospective, observational study was undertaken in 70 consecutive patients with high trans-sphincteric fistula treated by SSF (n = 35) or N-SSF (n = 35). Anal manometry was performed before and 3 months after surgery. Anal continence was assessed using the Cleveland Clinic Florida Incontinence Score. There was no difference between the two groups in age, gender, presence of horseshoe extension, preoperative incontinence score and manometric values. The incidence of recurrence was similar between the two groups. The postoperative incontinence score of the SSF group was significantly higher than that of the N-SSF group (1.9 +/- 2.9 vs 1.1 +/- 2.9, P = 0.0347). Maximum resting pressure showed significant decrease after surgery in both groups (83.2 to 56.1 mmHg, P = 0.0001 and 85.1 to 58.4 mmHg, P = 0.0001). Voluntary contraction pressure and functional anal canal length did not change after N-SSF (137.6 to 138.2 mmHg, P = 0.9524 and 4.06 to 4.07 cm, P = 0.9524), but significantly decreased after SSF (120.2 to 96.7 mmHg, P = 0.0085 and 4.12 to 3.74 cm, P = 0.0183). Non-sphincter splitting fistulectomy for high trans-sphincteric fistula provided better functional results than fistulotomy. Less impairment of anal continence was achieved possibly not only by maintenance of the external anal sphincter function but also by preservation of the length of the high-pressure zone.

Augmented unilateral gluteoplasty with fascia lata graft in fecal incontinence.

This study was undertaken to evaluate the results of augmented unilateral gluteoplasty with fascia lata graft in patients with fecal incontinence due to congenital or neurologic disorders. Between January 2000 and January 2001, we performed a prospective study of 11 patients with longstanding fecal incontinence (stage C3 according to Pescatori scoring system for fecal incontinence). The patients included one girl and 10 boys aged 5-19 years who had already undergone Swenson's operation for congenital megacolon (7 patients) or abdominoperineal pull-through for high imperforate anus (4 patients). Preoperative anorectal manometric studies (maximum resting pressure, maximum squeeze pressure, rectoanal inhibitory reflex and functional anal canal length), saline enema test and magnetic resonance imaging (MRI) studies were done. Unilateral gluteoplasty augmented with fascia lata graft was wrapped around the anal canal. Biofeedback retraining was started at the beginning of the fourth postoperative week. Patients were followed both objectively and subjectively for about 6-18 months. Eight of 11 patients (72.7%) were clinically improved, as shown by the change in incontinence score ( p=0.01). this was confirmed by the significant changes in manometric studies, functional anal canal length, rectoanal inhibitory reflex and saline enema test. MRI done one month postoperatively showed disruption in one patient. Unilateral gluteoplasty augmented with fascia lata graft leads to encouraging results in patients with end-stage anal incontinence due to irreversible damage to anal sphincter with less incidence of morbidity that could be related to tension on either the muscle flap or its neurovascular bundle.

Computerized anal vector manometric analysis in patients treated by tailored lateral spincterotomy for anal fissure

Tailored lateral shincterotomy (TLS) was designed to preserve more sphincter by tailoring the vertical height of sphincter division to the length of the fissure. The aim of this study was to evaluate prospectively the effect of tailored lateral sphincterotomy on the anal sphincter function in patients with chronic anal fissure. Using a water-perfused 8-channel catheter, a computer-generated anal vector manometric study was performed (preoperatively, 1 and 5 weeks after tailored sphincterotomy) for 30 patients with chronic anal fissure and 20 controls. The mean resting anal pressure (MRAP) in patients with anal fissure was significantly higher (90.93±20.48 cm H2O) than in controls (64.9±11.90 cm H2O). Twenty-one patients (70%) had high MRAP (hypertensive) while 9 patients (30%) had normal MRAP (normotensive). Resting anal pressure at 1 cm from the anal verge (RAP-1 cm) in patients with chronic fissure was significantly higher than global RAP (p=0.00358). There was no significant difference between mean RAP-1 cm of normotensives and hypertensives. Normotensive patients had significantly shorter functional anal canal length (FACL, 2.7±0.26 cm) and shorter high pressure segment (HPS, 0.70±0.26 cm), which is more distally located (D1/D2 ratio, 0.80±0.17) than did hypertensive patients (FACL, 3.30±0.25 cm; HPS, 1.05±0.36 cm; D1/D2=1.18±0.46). The percent MRAP reduction was nearly constant after TLS, regardless of the type of patients (36.85±15.04% in hypertensives, 30.48±16.62% in normotensives). TLS resulted in hypotonia, which was more evident in females (MRAP=57.00±7.75 cm H2O) and normotensive patients (MRAP=48.60±9.08 cm H2O). Two patients (6.66%) had persistent fissure after TLS. Soiling and imperfect control of flatus were reported by two patients (6.66%). Following tailored lateral shincterotomy, the anal physiology was significantly more preserved in hypertensive than in normotensive patients. The success rate of TLS closely approximated that of traditional lateral sphincterotomy with less incidence of continence disorders. A more careful preservation of the sphincter is required in normotensive patients.

The value of sphincter asymmetry index in anal incontinence.

We tested the value of the sphincter asymmetry index (SAI), an adjunct study of vectormanometry for detecting sphincter defects of difficult clinical diagnosis, in patients with anal incontinence referred for anal manometry. Patients were prospectively classified as having no previous anal trauma (group I, n = 13), those with possible trauma (including previous vaginal delivery and anorectal surgery unrelated to the onset of incontinence; group II, n = 53), and those with previous anal trauma directly related by the patient to the onset of symptoms (group III, n = 39). These were compared to 30 healthy volunteers. Clinical data were compiled to obtain an incontinence score, sphincter defect, mean and maximal pressures, functional anal canal length, and SAI for both resting and squeeze pressure profiles. SAI values for the control group were 7.2 +/- 2.3% and 5.8 +/- 2.4% for resting and squeeze pressures, respectively. Female controls had shorter anal canals (P = 0.0001) and higher SAI during squeeze (P < 0.005) than male controls. Incontinence scores were 6.1 +/- 3.1, 8.6 +/- 3.9, and 12.5 +/- 4.9, in groups I, II, and III, respectively (P < 0.001). Mean SAI values at rest were 10.3 +/- 4.9% in group I, 19.0 +/- 10.6% in group II, and 23.6 +/- 14.0% in group III (P < 0.001); corresponding values during squeeze were 8.6 +/- 5.3%, 13.9 +/- 7.9%, and 16.8 +/- 8.0% (P < 0.01). Pressure profiles both at rest and during squeeze were inversely correlated with SAI; therefore the accuracy of SAI was not affected in patients with severe incontinence. Incontinent patients with a previous history of sphincter trauma thus had more severe incontinence, both clinically and manometrically, and higher SAI values than patients without prior trauma. The analysis of the SAI is a valuable tool for determining a traumatic cause of anal incontinence.

Anorectal physiological testing before and after a successful sphincter repair: a prospective study

Anorectal physiological testing often yields contradictory results in patients with faecal incontinence. This prospective study aims to determine if there are any discriminatory changes in anorectal physiological testing after a successful sphincter repair for sphincter defects. From 1995 to 1998, 20 consecutive females who underwent a successful overlapping sphincter repair for sphincter defect were evaluated by anorectal manometry and neurophysiologic testing before and 2-4 months after surgery. The sphincter defect was diagnosed preoperatively by clinical and endosonographic examination, confirmed at surgery. The severity of faecal incontinence was evaluated using the Cleveland Clinic Continence Score (0-20): 0 being perfect continence, and 20 being complete incontinence. Of 20 consecutive patients who were improved following direct sphincter repair, 12 had significant improvement with a median score of 3 (range 1-6), while eight had mild improvement with a median score of 9 (range 7-12). There was a significant improvement in the mean resting anal canal pressure (80 vs 50 mmHg; P=0.016), maximum squeeze anal canal pressure (120 vs 80 mmHg; P=0.0002) and functional anal canal length (3 vs 2 cm; P=0.0069) post-operatively, with significant improvement in faecal continence following sphincter repair. However, a mild improvement in faecal continence was not associated with any significant changes in the mean resting anal canal pressure (50 vs 40 mmHg; P=0.089), maximum squeeze anal canal pressures (100 vs 100 mmHg; P=0.19) or functional anal canal length (2 vs 2 cm; P=0.47). Marked improvement of faecal continence after overlapping sphincter repair is reflected by a marked increase in the mean resting anal canal pressure, maximum squeeze anal canal pressures and functional anal canal length.

Alteration of maximum anal resting pressure by digital rectal examination prior to manometry: analysis of agreement between repeat measurements.

To study whether digital examination preceding anal manometry causes significant alteration of maximum resting pressure reading and to quantify the discrepancies, 78 individuals (64 incontinent, 14 controls) were investigated. Recordings of maximum resting pressure were taken before and after digital rectal examination. There was a mean discrepancy of only -1.8 cms H2O between the readings and excellent correlation, but analysis of agreement revealed a bias that tended to be greater with smaller measurements and unacceptable variability between test results. Furthermore, the bias was not related to age, gender, the grade of incontinence, maximum voluntary contraction, functional anal canal length and threshold volume. Digital rectal examination prior to manometry causes unpredictable results especially in patients with lower maximum resting pressures and should strictly be avoided.

Impaired Anal Sensation and Early Diabetic Faecal Incontinence

Faecal incontinence develops in up to 20% of diabetic patients. To try to determine the relative contributions of sensory and motor neuropathy in this troublesome complication, anorectal function was examined in 10 male diabetic patients with early faecal incontinence (mucus leakage or faecal staining without the need to wear a pad), 10 asymptomatic male diabetic patients, and 10 normal control subjects. Motor function was tested using anal manometry to determine the resting and maximum squeeze pressure, and the functional anal canal length. No significant differences were found between the groups. Sensory function was tested by measuring the mucosal sensitivity to electrical stimulation, and the response to inflation of a balloon in the rectum. In the mid-anal canal position the symptomatic patients had a significantly higher sensory threshold at 6.6 +/- 2.8 mA compared with 3.0 +/- 1.2 mA in the normal control subjects (p less than 0.002), and in the high anal zone symptomatic patients had a significantly elevated sensory threshold at 9.1 +/- 2.0 mA compared with 4.6 +/- 1.6 mA in asymptomatic patients and 3.6 +/- 1.3 mA in the normal control subjects (both p less than 0.001). There were no significant differences in the first sensation of fullness, maximum tolerated volume or percentage fall from resting pressure between the groups on inflation of the balloon. Elevation of the sensory threshold in the upper anal canal is an early abnormality in the development of diabetic faecal incontinence.