CONTRIBUTION OF THE EXTERNAL ANAL SPHINCTER TO THE PRESSURE ZONE IN THE ANAL CANAL

Long-term Outcomes of Botulinum Toxin Injection Into the External Anal Sphincters: An Effective New Treatment of Chronic Functional Constipation in Children

BACKGROUND

Botulinum toxin (BT) is a well-recognised treatment of chronic functional constipation (FC) and soiling refractory to medical treatment. The aims of this study were to assess the short and long-term outcomes of BT injection into the external anal sphincter muscles (EAS) for chronic FC treatment.

METHODS

We studied 196 children unresponsive to medical management of chronic FC, soiling, painful defecation and withholding behaviour (Rome III criteria) from April 2011 to January 2023. All patients underwent anorectal manometry (ARM) and endosonography-guided BT injection (Dysport® or Botox®) 10 units/kg body weight (maximum 200 units) into the EAS muscles at 3 and 9 o'clock positions and colonic transit study. Outcomes were measured using a validated symptom severity (SS) score questionnaire pre-operatively, at 3-6 months and 12-24 months follow up including: defecation frequency and pain, soiling, laxative(s), general health, behaviour, symptom improvement and faecaloma. Sum of scores ranged from 0 (best) to 65 (worst). We used Wilcoxon signed-rank test for matched-pairs related analysis and data presented as median (range) and p value < 0.05 was considered significant.

RESULTS

196 patients (104 male) with a median age of 7 (1-16) years underwent anorectal investigations and BT injection into the external anal sphincters during 12 year study period. The median short and long term follow-up was 4 (1-27) months and 16 (5-60) months, respectively. 26 (13 %) patients had autism and 14 (7.1 %) had attention deficit hyperactivity disorder (ADHD). Median anal sphincter resting pressure was of 55 (20.5-113) mmHg. The pre-operative total SS score improved from median 31/65 (4-57) before BT treatment to median 15/65 (0-49) at 4-month after BT injection and median 16/65 (0-56) at 16-month follow-up, p < 0.001. 80 % (104/130) of patients showed significant short-term and 79 % (71/90) showed long-term improvement of their chronic FC symptoms following BT injections. 9 % (18/196) children required second BT injection for symptom recurrence and 18.3 % (36/196) required formation of an antegrade colonic enema (ACE) stoma.

CONCLUSION

BT injection is an effective and safe new treatment of chronic FC unresponsive to conventional medical treatments. In our experience, 80 % of children have significant improvement of their symptoms and 9 % require repeat BT injection during a long term follow-up.

Does transanal endoscopic microsurgery affect rectal function?

PURPOSE

Transanal endoscopic microsurgery (TEM) is the most standardized method for the local excision of rectal neoplasms. Unfortunately, local excisions of rectal lesions by means of TEM are not completely free from undesirable functional sequela. This study was performed to evaluate the risk factors of major loss of function after TEM.

METHODS

Eighty-nine patients underwent TEM between 2019 and 2020. Anorectal manometry was performed before the surgery and 3, 6, and 12 months after the surgery. The quality of life (QoL) was assessed using the Fecal Incontinence Quality of Life scale.

RESULTS

The major decrease in QoL was observed in women in 3 months after the surgery in terms of lifestyle and frustration domains (3.6 and 3.64 points, respectively). In 3 months after the surgery, there was a significant decrease in resting pressure both in male and female patients (P=0.01). This difference remained significant 6 months after the surgery (P=0.01). In 12 months after the surgery, resting pressure returned to the preoperative level in most patients (P=0.50). A significant decrease in manometric parameters appeared when the surgery time is more than 55 minutes (P=0.05), the tumor localization is lower than 3 cm from the anus (P=0.03), and the tumor size is over 3 cm (P=0.001).

CONCLUSION

The most significant risk factors for the development of functional disorders after TEM are surgery time of >55 minutes, tumor localization at <3 cm from the anal verge, and tumor size of >3 cm.

Evaluation and Management of Postsurgical Patient With Hirschsprung Disease Neurogastroenterology & Motility Committee: Position Paper of North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN)

Children with Hirschsprung disease have postoperative long-term sequelae in defecation that contribute to morbidity and mortality and significantly impact their quality of life. Pediatric patients experience ongoing long-term defecation concerns, which can include fecal incontinence (FI) and postoperative obstructive symptoms, such as constipation and Hirschsprung-associated enterocolitis. The American Pediatric Surgical Association has developed guidelines for management of these postoperative obstructive symptoms and FI. However, the evaluation and management of patients with postoperative defecation problems varies among different pediatric gastroenterology centers. This position paper from the Neurogastroenterology & Motility Committee of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition reviews the current evidence and provides suggestions for the evaluation and management of postoperative patients with Hirschsprung disease who present with persistent defecation problems.

Three-dimensional high-resolution anorectal manometry: A comparative pilot study with X-ray defaecography

Three-dimensional high-resolution anorectal manometry (3DHRAM) is a new technique that can explore anorectal disorders and provide interesting topographic data for the diagnosis of pelvic floor disorders such as paradoxical puborectalis syndrome (PPS). Our object was to evaluate whether 3DHRAM can reliably diagnose PPS already diagnosed with X-ray defaecography, which is considered to be the gold standard. All patients being tested in our department for dyschezia by 3D-HRAM and X-ray defecography were eligible for the study. The 3DHRAM results were compared with X-ray defecography. The sensitivity, specificity, and positive and negative predictive values were calculated for various 3DHRAM criteria to propose a diagnostic strategy for PPS. Twenty-three patients presented with PPS on X-ray defaecography. On 3DHRAM, according to our diagnostic strategy, the kappa value was 0.706, with a positive predictive value of 71.88% [95% CI, 53.02-85.60], a specificity of 80.43% [95% CI, 65.62-90.13], a sensibility of 95.83% [95% CI, 76.98-99.78], and area under curve value was 0.922. In this study, 3DHRAM was used to diagnose PPS with the same degree of reliability as X-ray defaecography, and we confirmed its use in the diagnosis of pelvic floor disorders. Further studies will be necessary to define classifications for these new anatomic data from 3DHRAM.

Faecal incontinence in adults

Faecal incontinence, which is defined by the unintentional loss of solid or liquid stool, has a worldwide prevalence of ≤7% in community-dwelling adults and can markedly impair quality of life. Nonetheless, many patients might not volunteer the symptom owing to embarrassment. Bowel disturbances, particularly diarrhoea, anal sphincter trauma (obstetrical injury or previous surgery), rectal urgency and burden of chronic illness are the main risk factors for faecal incontinence; others include neurological disorders, inflammatory bowel disease and pelvic floor anatomical disturbances. Faecal incontinence is classified by its type (urge, passive or combined), aetiology (anorectal disturbance, bowel symptoms or both) and severity, which is derived from the frequency, volume, consistency and nature (urge or passive) of stool leakage. Guided by the clinical features, diagnostic tests and therapies are implemented stepwise. When simple measures (for example, bowel modifiers such as fibre supplements, laxatives and anti-diarrhoeal agents) fail, anorectal manometry and other tests (endoanal imaging, defecography, rectal compliance and sensation, and anal neurophysiological tests) are performed as necessary. Non-surgical options (diet and lifestyle modification, behavioural measures, including biofeedback therapy, pharmacotherapy for constipation or diarrhoea, and anal or vaginal barrier devices) are often effective, especially in patients with mild faecal incontinence. Thereafter, perianal bulking agents, sacral neuromodulation and other surgeries may be considered when necessary.

Differences in fatigability of muscles involved in fecal continence: Potential clinical ramifications

INTRODUCTION

Fatigue of the anal sphincter complex has been demonstrated using high-resolution anorectal manometry (HRAM). However, the fatigability of individual muscles such as the external anal sphincter (EAS) and puborectalis muscles (PRM) has not been described. Vaginal manometry has been used to study contractile activity of the PRM. By applying both modalities, we attempted to differentiate the fatigability between the PRM and the EAS under different exercise conditions.

METHODS

We studied two groups: group 1, 12 healthy women (21 ± 2.7 years) with HRAM and group 2, 10 healthy (20 ± 3 years) women with vaginal manometry. All subjects performed 40 repetitive contractions with and without an intra-anal resistive load. In group 1, areas under the curve (AUC) of the anal canal high-pressure zone (HPZ) including the caudal and rostral halves were compared. In group 2, the maximum and mean pressures of the vaginal HPZ were compared.

RESULTS

The AUC decreased significantly only after repetitive contractions against a resistive load (462 ± 129 vs. 390 ± 131 mmHg-cm, p = 0.02), indicating fatigue. The caudal half (EAS) decreased significantly after contractions against a load (288 ± 75 vs. 239 ± 82 mmHg-cm, p = 0.02), while the rostral half (PRM) did not. The vaginal pressures (PRM) also decreased only after repetitive contractions against a load (maximum pressures, 358 ± 171 vs. 239 ± 109 mmHg, p = 0.02).

CONCLUSIONS

The EAS and PRM both exhibit fatigue with contractions only against a resistive load. These findings may guide the development of appropriate exercise regimens to target specific muscles involved in fecal continence.

Colorectal barotrauma following compressed air spray to the perineum

Colorectal injuries caused by high-pressure air compressors are rare and reported especially among industrial workers. They may appear because of intended or accidental injury. In the present paper, we report a case of colorectal injuries due to air insufflation from a distance towards the anus with the clothes on, as a means of a practical joke. The patient presented one day after the trauma to the Emergency Department with complaints of severe abdominal pain and vomiting. On examination, he had signs of peritonitis. A computed tomography (CT) scan did not show any perforation. Emergency laparotomy was performed with the suspicion of pneumatic pressure-induced lesions. A total resection of the colon was made with enterostomy. The pathologic examination of the resected piece revealed multiple gangrenous areas without perforation associated to signs of peritonitis. Follow up was uneventful. A reversal of the enterostomy was scheduled.

Optimal timing of definitive surgery for Hirschsprung's disease to achieve better long-term bowel function

PURPOSE

Few studies have focused on the operative age for Hirschsprung's disease (HD). We evaluated the optimal timing of surgery in HD patients based on their long-term bowel function.

METHODS

HD was diagnosed in 65 pediatric patients in our institute between 1992 and 2018. Twenty-five patients underwent the Soave-Denda procedure (SD) and 40 underwent transanal endorectal pull-through (TA). We divided these patients into two groups: those who underwent surgery at < 6 months of age (younger group) and those who underwent surgery at 6-12 months of age (older group). We assessed bowel function at 5, 7, and 9 years of age.

RESULTS

The bowel function of the patients who underwent the SD did not differ significantly between the groups. Similarly, the total bowel-function scores of the patients who underwent TA did not differ between the groups at any age. However, the soiling score at 7 years of age in the older group of patients who underwent TA was significantly lower than that in the younger group (p = 0.02).

CONCLUSIONS

Our data suggest that to achieve optimal bowel function, TA should be performed at < 6 months of age.

Comparison of longitudinal and radial characteristics of intra-anal pressures using 3D high-definition anorectal manometry between children with anoretal malformations and functional constipation

BACKGROUND

Pathophysiology of fecal incontinence (FI) in children with anorectal malformations (AM) is not well understood. Standard or high-resolution anorectal manometry (ARM) does not identify radial asymmetry or localize abnormal sphincter function. 3D high-definition anorectal manometry (HDARM) provides detailed topographic and 3D pressure gradient representation of anal canal.

AIMS

To compare intra-anal pressure profiles between children with AM and controls using HDARM and to determine the association between manometric properties and reported predictors of fecal continence (AM type, spinal anomaly, and sacral integrity).

METHODS

HDARM tracings of 30 children with AM and FI referred for ARM were compared with 30 age and sex-matched children with constipation. 2D pressure profiles were used to measure length of high-pressure zone (HPZ). Longitudinal and radial measurements of sphincter pressure at rest and squeeze were taken along each segment in 3D topographic views and compared between groups.

KEY RESULTS

3D measurements demonstrated longitudinal and radial differences between groups along all quadrants of HPZ. At rest, intra-anal pressures were lower along the four segments longitudinally across the anal canal and radially along the quadrants in AM group (P < .01). At squeeze, all quadrant pressures were lower in segments 1-4 in AM group (P < .01). Sensation was abnormal in AM group (P < .01). Intra-anal pressures longitudinally and radially were not associated with predictors of fecal continence.

CONCLUSIONS AND INFERENCES

Children with AM had abnormal sensation and lower pressures longitudinally and radially along all quadrants of anal canal. Manometric properties at rest were not associated with reported predictors of fecal continence.

A novel method for measurement of the recto-anal inhibitory reflex using anal acoustic reflectometry

AIM

The recto-anal inhibitory reflex (RAIR) is currently measured using manometry catheters, which potentially distort the anal canal. Anal acoustic reflectometry (AAR) is considered to be a catheter-free technique and primarily measures the function of the internal anal sphincter. We sought to determine if RAIR could be measured using AAR.

METHOD

Patients aged 18 and over attending the hospital for investigation of pelvic floor dysfunction were included. AAR parameters were obtained before (prerectal distension) and after (postrectal distension) inflation of a rectal balloon catheter with 100 ml of air. Minimum opening pressure (Op, cmH₂ O), opening elastance (Oe, cmH₂ O/mm² ), closing pressure (Cp, cmH₂ O), closing elastance (Ce, cmH₂ O/mm² ) and hysteresis (Hys, %) were recorded. The presence of RAIR was defined by a reduction of prerectal distension Op by 20% or more.

RESULTS

Thirty-two patients were included, 26 of whom were women. The mean age of patients was 57.5 years (SD 11.3 years). Nine patients had faecal incontinence, six patients had obstructive defaecation and 17 patients had both. RAIR was seen in 30/32 patients. The mean reduction in Op was 58.8% (range -59.18% to 100%). Three patients had 100% reduction. Comparison of pre- and post-RAIR parameters showed a significant difference in Op (34.44 vs 15.41, P < 0.0001), Oe (1.39 vs 1.1, P = 0.004), Cp (20.06 vs 8.00, P < 0.0001) and Ce (1.31 vs 1.13, P < 0.0001) but not Hys (39.71 vs 39.90, P = 0.88).

CONCLUSION

We describe a novel method for the measurement of RAIR. Rectal distension appears to alter resting pressure and the resistance of the anal canal to opening and closing, with complete inhibition of the sphincter complex in three patients.

Placement of a fine-bore rectal balloon catheter in the anal canal does not affect anal sphincter pressures: improving our understanding of physiological function with anal acoustic reflectometry

AIM

The recto-anal inhibitory reflex (RAIR) is currently measured using anorectal manometry catheters, which may distort the anal canal. Anal acoustic reflectometry (AAR) is considered a catheter-free technique for evaluating the physiological function of the anal canal; however, it has yet to be used to elicit the RAIR. For the RAIR to be measured with AAR, the effect of placing an additional rectal balloon catheter on the measured AAR parameters needs to be investigated: that is the aim of this work.

METHOD

Patients aged over 18 years attending hospital for the investigation of pelvic floor disorders were included. AAR parameters were obtained before and after a rectal balloon catheter was placed alongside the AAR catheter. The following parameters were measured: 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 ).

RESULTS

Thirty-five patients were included in the analysis, of whom 28 were women. The median age was 58 years. Comparison of median AAR parameters before and after catheter placement showed no significant difference: Op (36.36 vs 33.42, P = 0.09), Oe (1.27 vs 1.39, P = 0.19), Cp (18.62 vs 19.73, P = 0.13), Ce (1.2 vs 1.28, P = 0.33), Hys (41.08 vs 40.11, P = 0.17), SqOp (81.85 vs 81.65, P = 0.93) and SqOe (1.44 vs 1.49, P = 0.55).

DISCUSSION

Placement of a rectal balloon catheter alongside the AAR catheter has no significant effect on the measured AAR parameters. The results of this study add to the fundamental basic science and understanding of the physiological function of the anal canal.

Simulated stool for assessment of anorectal physiology

Fecal continence is maintained by several mechanisms including anatomical factors, anorectal sensation, rectal compliance, stool consistency, anal muscle strength, mobility, and psychological factors. The homeostatic balance is easily disturbed, resulting in symptoms including fecal incontinence and constipation. Current technologies for assessment of anorectal function have limitations. Overlap exist between data obtained in different patient groups, and there is lack of correlation between measurements and symptoms. This review describes a novel technology named Fecobionics for assessment of anorectal physiology. Fecobionics is a simulated stool, capable of dynamic measurements of a variety of variables during defecation in a single examination. The data facilitate novel analysis of defecatory function as well as providing the foundation for modeling studies of anorectal behavior. The advanced analysis can enhance our physiological understanding of defecation and future interdisciplinary research for unraveling defecatory function, anorectal sensory-motor disorders, and symptoms. This is a step in the direction of improved diagnosis of anorectal diseases.

A Case of Pneumatic Rectal Perforation Caused by Compressed Air

Rectal perforation is a rare cause of acute abdomen. The most common cause of rectal perforation is trauma. Barotrauma due to the injection of compressed air in the rectum is an extremely rare cause of rectal perforation. We report a case of extensive pneumoperitoneum with abdominal compartment syndrome caused by rectal perforation secondary to the forceful injection of compressed air through the perineum. The patient was successfully managed by immediate relief of abdominal compartment syndrome by needle decompression followed by surgical repair of rectal perforation.

Duration taken for the anal sphincter pressures to stabilize prior to anorectal manometry

OBJECTIVES

Anorectal manometry (ARM) is an integral part of evaluating the anal sphincter function. The current recommendation of waiting for 5 min (lead-in-time) prior to beginning the recording has no evidence. A prolonged procedure may reduce patient compliance.

RESULTS

We analyzed data from 100 consecutive patients who underwent 3-dimensional ARM at a single center. Their pressure studies were analyzed in consecutive 10-s segments, beginning from the time of insertion of the probe into the anal canal. We defined stabilization of the pressure as the absence of a pressure difference among two consecutive 10-s segments. The study population had 31 males. Their mean age was 33.0 years (SD-14.4). The mean time for the pressure to stabilize was 84.2 s (SD-29.5), range 17.2-203.7 s, 95th percentile 136.2 s. Eleven and one participant(s) took longer than 120 and 150 s for the pressure to stabilize, respectively. There was no correlation of sex (Mann-Whitney U test, p = 0.89) and the time to pressure stabilization. Age and the time to stabilize (Spearman rho - 0.246, p = 0.017) showed a weak negative correlation. A lead-in-time of 5 min, as recommended by present guidelines may be unnecessary. Waiting for 150 s/2½ min may be sufficient and will minimize the procedure duration.

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.

Three-Dimensional Anorectal Manometry Findings in Primigravida

BACKGROUND

Vaginal delivery is an identified risk factor for anal sphincter injury. Therefore, to identify postpartum injury, an antepartum value or a normal range is required. However, at present, the normal values of 3D manometry are not available for primigravida or pregnant mothers.

AIMS

Our study aims at describing normal values of 3D manometry in primigravida.

METHODS

We analyzed 3DARM data of 101 consecutive primigravid mothers in the third trimester. 3DARM was performed using the Given Imaging(®) ManoScan system.

RESULTS

The mean age was 24.7 (SD 5.1) years. All patients had a normal Cleveland Clinic Incontinence Score. The mean resting pressure (RP) was 87.02 (SD 18.43) mmHg and the maximum squeeze pressure (SP) was 179.21 (SD 52.96) mmHg. The mean length of the high-pressure zone (HPZ) was 3.67 (SD 0.52) cm. Mean volumes for initial rectal sensation, urge, and discomfort were 50.36 (± 25.57), 76.70 (± 35.17), and 143.40 (± 66.26) ml, respectively. The pressure asymmetry was highest in the lower anal sphincter and lowest in the mid-sphincter. There was a statistically significant relationship between the HPZ and RP (Pearson ρ -0.23, p = 0.01), height (Pearson ρ 0.22, p = 0.028), and weight (Pearson ρ 0.25, p = 0.012). There were no statistically significant correlations between age, height, or weight with RP, SP, or balloon fill volumes. The characteristic appearance of the normal RP and SP was clearly visualized in all patients.

CONCLUSIONS

Normal 3DARM values for Sri Lankan primigravid mothers have been established. These may be used as reference values by other investigators.

Correlation of three dimensional anorectal manometry and three dimensional endoanal ultrasound findings in primi gravida: a cross sectional study

Background

3-dimensional anorectal manometry (3DARM) and 3-dimensional endoanal ultrasound (3DEAUS) have not been used to assess the anal sphincter complex (ASC) in primi gravida. This study was conducted to identify any correlation that may exist between 3DARM and 3DEAUS.

Methods

We analyzed 3DARM and 3DEAUS data of 101 consecutive primi mothers assessed in the late second trimester or early 3rd trimester. 3DARM was performed using the Given Imaging^® Manoscan system and 3DEAUS was performed with the Olympus^® RU 12M-R1 probe and EU-ME1 ultrasound system.

Results

The mean age was 24.7 (SD—5.1) years. All patients had a normal Cleveland Clinic Incontinence Score. The mean resting pressure (RP) was 87.02 (SD—18.43) mmHg and the maximum squeeze pressure (SP) was 179.21 (SD—52.96) mmHg. The mean length of the high pressure zone was 3.67 (SD—0.52) cm. On 3DEAUS, there were three characteristic segments of the ASC that were identified; upper, middle and lower. Mean thicknesses for both internal anal sphincter (IAS) and external anal sphincter (EAS) were identified for primi gravida. IAS was thicker anteriorly and at 9 o’ clock positions and EAS was thicker posteriorly. There was good correlation in the length of the ASC at each quadrant between 3DARM and 3DEAUS. There was no correlation between either RP or SP thickness of IAS or EAS at each level and quadrant.

Conclusion

Correlation is seen only in the length of ASC at each quadrant. No correlation exist between RP or SP and thickness of IAS and EAS.

Functional outcome of autologous anorectal transplantation in an experimental model

BACKGROUND

Although anorectal transplantation is a challenging procedure, it is a promising option for patients who have completely lost anorectal function or in whom it failed to develop, as in congenital malformations. The paucity of animal models with which to test functional outcomes was addressed in this study of anorectal manometry in rats.

METHODS

Wistar rats were assigned randomly to four groups: orthotopic anorectal transplantation, heterotopic transplantation, sham operation, or normal control. Bodyweight and anal pressure were measured immediately before and after operation, and on postoperative days 7 and 14. ANOVA and Tukey's test were used to compare results for bodyweight, anal manometry and length of procedure.

RESULTS

Immediately after the procedure, mean(s.d.) anal pressure in the orthotopic group (n = 13) dropped from 31·4(13·1) to 1·6(13·1) cmH2 O (P < 0·001 versus both sham operation (n = 13) and normal control (n = 15)), with partial recovery on postoperative day 7 (14·9(13·9) cmH2 O) (P = 0·009 versus normal control) and complete recovery on day 14 (23·7(12·2) cmH2 O). Heterotopic rats (n = 14) demonstrated partial functional recovery: mean(s.d.) anal pressure was 26·9(10·9) cmH2 O before operation and 8·6(6·8) cmH2 O on postoperative day 14 (P < 0·001 versus both sham and normal control).

CONCLUSION

Orthotopic anorectal transplantation may result in better functional outcomes than heterotopic procedures. Surgical relevance Patients with a permanent colostomy have limited continence. Treatment options are available, but anorectal transplantation may offer hope. Some experimental studies have been conducted, but available data are currently insufficient to translate into a clinical option. This paper details functional outcomes in a rat model of anorectal autotransplantation. It represents a step in the translational research that may lead to restoration of anorectal function in patients who have lost or have failed to develop it.

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

INTRODUCTION

Anorectal 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.

METHODS

This 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.

RESULTS

The 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.

CONCLUSIONS

Ketamine 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.

Pneumatic colon injury following high pressure blow gun dust cleaner spray to the perineum

•

Accident related pneumatic colon perforation is difficult to diagnose in children preoperatively as they are anxious to tell the history of trauma.

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The presence of pneumoperitoneum always leads to exploratory laparotomy.

•

The sudden onset of tension pneumoperitoneum, intraoperative of multiple site colon injury with or without perforation in normal children should suspect the presence of trauma.

•

Creation of ostomy at the site of normal looking colon preferable to colon resection.

Introduction

A pneumatic tool or air tool such as blow gun dust cleaner is a tool driven by compressed air and spraying of the perineum can insufflate the colon due to its high pressure and high flow rate.

Presentation of case

We present a case of 4 year old boy who developed sudden onset of tense abdominal distention and developed peritonitis. Patient’s family initially denied a history of trauma. Radiologic examination showed pneumoperitoneum and colon dilatation. Exploratory laparotomy revealed a tension pneumoperitoneum, bloody ascitic fluid, multiple site of ecchymosis and serosal tear of the colon and a minute perforation of transverse colon. Postoperative reinvestigation revealed that the patient’s perineum was sprayed, using blow gun dust cleaner.

Discussion

Air from pneumatic tools produces column of air at pressure of 3.5–8.8 kg/cm² and pressure greater than the resting anal pressure of 0.109 kg/cm² force air to enter the colon when the perineum is sprayed. Different degree of colon injury results when airflow is greater than 1.46 L/m, and/or intraluminal pressure greater than 0.109 kg/cm². In most children, initial anxiety to tell the truth result in difficulty to obtain good history.

Conclusion

Spraying of the perianal with excessive pneumatic force of greater than the resting anal pressure and high air flow rate causes multiple site colon injury and tension pneumoperitoneum due to colon perforation. Parent should be caution in children playing with high pressure pneumatic tool, and the importance of history is emphases for early correct diagnosis.

Three-dimensional high-resolution anorectal manometry in the diagnosis of paradoxical puborectalis syndrome compared with healthy adults: a retrospective study in 79 cases

OBJECTIVES

The aim of this study is to evaluate the three-dimensional anorectal pressure topography of normal healthy adults and patients with paradoxical puborectalis syndrome (PPS) using a novel three-dimensional high-resolution manometry (3D-HRM) of the anorectum.

METHODS

The 3D-HRM probe has a 6.4 cm long sensing segment that is composed of 256 independent pressure transducers around its circumference. It generates a 3D pressure topographic profile of the anorectum. We evaluated 41 women and 38 men with PPS (median age 52 years), and compared them with 37 women and 34 men who were healthy (median age 51 years). The three-dimensional anorectal pressure topography was evaluated at rest, and during squeeze, stimulated defecation, and balloon inflation.

RESULTS

Maximum resting pressure, mean resting pressure, high pressure zone length, and residual anal pressure were significantly higher in patients with PPS compared with healthy adults (P<0.01 each). The rectoanal pressure differential was significantly lower in the PPS patients compared with healthy adults (P<0.05). There was a characteristic purple high-pressure area in the posterior wall of the pressure cylinder of patients with PPS during stimulated defecation that was absent in healthy adults. The longest diameter and widest diameter of this purple high-pressure area were 1.71 ± 0.25 and 1.07 ± 0.14 cm. The maximum, mean, and minimum pressures of the posterior distal pressure zone were significantly higher in patients with PPS (270.1 ± 8.2, 152.7 ± 4.8, and 51.9 ± 2.7 mmHg, respectively) compared with healthy adults (168.5 ± 11.1, 88.0 ± 5.9, and 30.7 ± 2.8 mmHg, respectively) (P<0.01).

CONCLUSION

Using the 3D-HRM technique, the increase in the resting pressure and residual anal pressure and decrease in the rectoanal pressure differential in patients with PPS compared with healthy adults further indicated the mechanism of this disease. Unlike traditional manometry, the 3D-HRM technique could find, locate, and evaluate the scope and the pressure of the paradoxical contraction of puborectalis muscle, which further indicates the value of manometry in terms of diagnosis.

Longitudinal and radial characteristics of intra-anal pressures in children using 3D high-definition anorectal manometry: new observations

OBJECTIVES

The pathophysiology of fecal incontinence is not well understood. Standard or high-resolution anorectal manometry (ARM) provides simple two-dimensional (2D) intra-anal pressure measurements and do not identify radial asymmetry or localize abnormal sphincter function. 3D high-definition ARM (HDARM) has 256 pressure sensors distributed circumferentially and provides a detailed topographical and 3D pressure gradient representation of the anal canal. The objective of this study was to use HDARM to characterize intra-anal pressure profiles in children during rest and squeeze.

METHODS

HDARM manometric tracings of 30 children with constipation referred for ARM were reviewed. 2D pressure profiles using high-resolution manometry were used to measure the length of the high-pressure zone (HPZ). The HPZ was divided into four equal segments from the anal verge to adjust for the variable sphincter length. Longitudinal and radial measurements of the HPZ during rest and squeeze (anterior, left, posterior, right quadrants of the HPZ) were taken along each segment in 2D and 3D topographical views. A 3D reconstruction combining all patients was then constructed.

RESULTS

Mean age was 149.3±1.8 months and mean HPZ length was 3.0±0.1 cm. Using 2D manometry, the mean peak HPZ pressure at rest was 72.0±2.5 mm Hg, and was located in the second segment of the HPZ. The mean peak HPZ pressure at squeeze was 202.9±13.1, and was located in the second segment. 3D measurement demonstrated both longitudinal and radial asymmetry along the anterior, left, posterior, and right quadrants of the HPZ. Left and right quadrant pressures were higher than anterior and posterior pressures at the anal verge and segment 1 during rest and squeeze. Anterior pressures were lower than posterior pressures longitudinally and radially in segments 2, 3, and 4 both during rest and squeeze. Our findings also suggest that in pediatrics it may be necessary to adjust pressure measurement to the anal canal length to get a more accurate picture.

CONCLUSIONS

3D HDARM allows for a detailed characterization of intra-anal pressures. 3D topographic pressure measurements demonstrate longitudinal and radial asymmetry of the anal canal at rest and during squeeze. This is the first time longitudinal and radial asymmetry of the anal canal has been described in children. 3D HDARM may allow for a better understanding of the mechanisms of fecal continence in children.

Anorectal functional outcome after repeated transanal endoscopic microsurgery

AIM: To evaluate the status of anorectal function after repeated transanal endoscopic microsurgery (TEM).

METHODS: Twenty-one patients undergoing subtotal colectomy with ileorectal anastomosis were included. There were more than 5 large (> 1 cm) polyps in the remaining rectum (range: 6-20 cm from the anal edge). All patients, 19 with villous adenomas and 2 with low-grade adenocarcinomas, underwent TEM with submucosal endoscopic excision at least twice between 2005 and 2011. Anorectal manometry and a questionnaire about incontinence were carried out at week 1 before operation, and at weeks 2 and 3 and 6 mo after the last operation. Anal resting pressure, maximum squeeze pressure, maximum tolerable volume (MTV) and rectoanal inhibitory reflexes (RAIR) were recorded. The integrity and thickness of the internal anal sphincter (IAS) and external anal sphincter (EAS) were also evaluated by endoanal ultrasonography. We determined the physical and mental health status with SF-36 score to assess the effect of multiple TEM on patient quality of life (QoL).

RESULTS: All patients answered the questionnaire. Apart from negative RAIR in 4 patients, all of the anorectal manometric values in the 21 patients were normal before operation. Mean anal resting pressure decreased from 38 ± 5 mmHg to 19 ± 3 mmHg (38 ± 5 mmHg vs 19 ± 3 mmHg, P = 0.000) and MTV from 165 ± 19 mL to 60 ± 11 mL (165 ± 19 mL vs 60 ± 11 mL, P = 0.000) at month 3 after surgery. Anal resting pressure and MTV were 37 ± 5 mmHg (38 ± 5 mmHg vs 37 ± 5 mmHg, P = 0.057) and 159 ± 19 mL (165 ± 19 mL vs 159 ± 19 mL, P = 0.071), respectively, at month 6 after TEM. Maximal squeeze pressure decreased from 171 ± 19 mmHg to 62 ± 12 mmHg (171 ± 19 mmHg vs 62 ± 12 mmHg, P = 0.000) at week 2 after operation, and returned to normal values by postoperative month 3 (171 ± 19 vs 166 ± 18, P = 0.051). RAIR were absent in 4 patients preoperatively and in 12 (χ² = 4.947, P = 0.026) patients at month 3 after surgery. RAIR was absent only in 5 patients at postoperative month 6 (χ² = 0.141, P = 0.707). Endosonography demonstrated that IAS disruption occurred in 8 patients, and 6 patients had temporary incontinence to flatus that was normalized by postoperative month 3. IAS thickness decreased from 1.9 ± 0.6 mm preoperatively to 1.3 ± 0.4 mm (1.9 ± 0.6 mm vs 1.3 ± 0.4 mm, P = 0.000) at postoperative month 3 and increased to 1.8 ± 0.5 mm (1.9 ± 0.6 mm vs 1.8 ± 0.5 mm, P = 0.239) at postoperative month 6. EAS thickness decreased from 3.7 ± 0.6 mm preoperatively to 3.5 ± 0.3 mm (3.7 ± 0.6 mm vs 3.5 ± 0.3 mm, P = 0.510) at month 3 and then increased to 3.6 ± 0.4 mm (3.7 ± 0.6 mm vs 3.6 ± 0.4 mm, P = 0.123) at month 6 after operation. Most patients had frequent stools per day and relatively high Wexner scores in a short time period. While actual fecal incontinence was exceptional, episodes of soiling were reported by 3 patients. With regard to the QoL, the physical and mental health status scores (SF-36) were 56.1 and 46.2 (50 in the general population), respectively.

CONCLUSION: The anorectal function after repeated TEM is preserved. Multiple TEM procedures are useful for resection of multi-polyps in the remaining rectum.

A prospective non-randomized two-centre study of patients with passive faecal incontinence after birth trauma and patients with soiling after anal surgery, treated by elastomer implants versus rectal irrigation

AIM

This study is a prospective evaluation of patients with passive faecal incontinence and patients with soiling treated by elastomer implants and rectal irrigation.

PATIENTS AND METHODS

Patients with passive faecal incontinence after birth trauma resulting from a defect of the internal sphincter and patients with soiling after previous anal surgery were included. All patients underwent endo-anal ultrasound, magnetic resonance imaging, and anal manometry. The patients with passive faecal incontinence were initially treated by anal sphincter exercises and biofeedback therapy during half a year. The patients completed incontinence scores, a quality of life questionnaire, and a 2-week diary card.

RESULTS

The elastomer group consisted of 30 males and 45 females with a mean age of 53 years (25-77). The rectal irrigation group consisted of 32 males and 43 females with a mean age of 50 years (25-74). At 6 months follow-up, 30 patients with soiling of the rectal irrigation group and only nine patients of the elastomer group were completely cured (p = 0.02). Only three patients with passive faecal incontinence were cured in the rectal irrigation group and none in the elastomer group. Three distal migrations of elastomer implants required removal at follow-up.

CONCLUSIONS

After patients had performed anal sphincter exercises, no clear improvement of passive faecal incontinence was obtained by elastomer implants or rectal irrigation. However, rectal irrigation is far more effective than elastomer implants in patients with soiling.

Should we care about the internal anal sphincter?

The internal anal sphincter is currently regarded as a significant contributor to continence function. Four physiological and morphological aspects of the internal anal sphincter are presented as part of the current evidence base for its preservation in anal surgery. 1) The incidence of continence disturbance following deliberate internal anal sphincterotomy is underestimated, although there is presently no prospective imaging or physiologic data supporting the selective use of sphincter-sparing surgical alternatives. 2) Given that the resting pressure is a measure of internal anal sphincter function, its physiologic representation (the rectoanal inhibitory reflex) shows inherent differences between incontinent and normal cohorts which suggest that internal anal sphincter properties act as a continence defense mechanism. 3) Anatomical differences in distal external anal sphincter overlap at the point of internal anal sphincter termination may preclude internal anal sphincter division in some patients where the distal anal canal will be unsupported following deliberate internal anal sphincterotomy. 4) internal anal sphincter-preservation techniques in fistula surgery may potentially safeguard postoperative function. Prospective, randomized trials using preoperative sphincter imaging and physiologic parameters of the rectoanal inhibitory reflex are required to shape surgical decision making in minor anorectal surgery in an effort to define whether alternatives to internal anal sphincter division lead to better functional outcomes.

Male faecal incontinence presents as two separate entities with implications for management

AIM

In contrast to females, male faecal incontinence has received little attention. We investigate its pattern and management at a large UK teaching hospital.

METHODS

Men presenting with faecal incontinence between January 2006 and December 2008 were identified from a gastrointestinal physiology database and classified into faecal leakage or faecal incontinence on the basis of symptomatology. Demographics, Cleveland Clinic incontinence score (CCIS), aetiological factors, investigations and treatments were collected by case note review and compared to clinical outcomes.

RESULTS

Forty-three symptomatic patients were identified with faecal incontinence, in which 33 were classified as having faecal leakage (FL) and ten as faecal incontinence (FI). The mean CCIS was 10.7 (range, 4-14) and 14.2 (8-20) for FL and FI, respectively. The FL group had normal anal sphincter pressures, whilst the FI group had significantly lower mean resting pressure, 45 mmHg (8-90 mmHg), and mean squeeze pressure, 62.1 mmHg (18-110 mmHg). Thirteen out of 33 patients in the FL group and seven out of ten in the FI group had undergone previous anorectal surgery and had demonstrable sphincter defects whilst in the remainder, no definite aetiological factor could be identified. All patients in the FL group improved with lifestyle changes (28/33) or biofeedback (5/33). Six patients in the FI group required surgical intervention (3/6, collagen injection; 1/6, graciloplasty; 1/6, sacral nerve stimulation; 1/6, rectopexy).

CONCLUSIONS

Patients presenting with FL characteristically have normal anorectal physiology and respond to non-operative measures, as compared to patients with FI who tend to have weakened anal sphincters, previous history of anorectal surgery, and more often require surgical intervention.

Novel applications of external anal sphincter muscle sarcomere length to enhance the anal canal function

BACKGROUND

Our recent studies show that the external anal sphincter muscle (EAS) operates at a sarcomere length range which is below optimal. In this study, we tested the hypothesis that by surgically increasing sarcomere length and bringing it close to the optimal length, EAS muscle function and anal canal pressure can be enhanced.

METHODS

Rabbits (n = 25) were anesthetized and subjected to either a sham or an EAS plication of different length by placing sutures at two locations, at a distance of 13%, 20%, 28%, or 35% of the circumferential length of the anal canal. Anal canal pressures were recorded before and after the plication. Anal canal was harvested and the EAS muscle sarcomere length was measured using laser diffraction.

KEY RESULTS

Electrical stimulation of the EAS muscle resulted in a stimulus-dependent increase in the anal canal pressure (mmHg) and EAS muscle stress (mN mm(-2)). A significant increase in maximal pressure (212 ± 13 after compared with 139 ± 22 before plication) as well as stress (166 ± 10 after as compared with 88 ± 14 before plication) was recorded at 20% plication length. Passive anal canal stress at 20% plication was not significantly different compared with the sham group. The mean sarcomere lengths with sham and 20% plication were 2.11 and 2.60 μm, respectively.

CONCLUSIONS & INFERENCES

EAS plication resulted in a length-dependent increase in EAS muscle sarcomere length with an optimal sarcomere length at 20% plication. These considerations may help guide repair of anal sphincter muscle defects in the humans.

Anorectal physiology: test and clinical application

The physiology of the anorectal region is very complex, and it is only recently that detailed investigations have given us a better understanding of its function. The methods that are used for the evaluation of anorectal physiology include anorectal manometry, defecography, continence tests, electromyography of the anal sphincter and the pelvic floor, and nerve stimulation tests. These techniques furnish a clearer picture of the mechanisms of anorectal disease and demonstrate pathophysiologic abnormalities in patients with disorders of the anorectal region. Therefore, therapeutic recommendations for anorectal disease can be made best when the anatomy and the physiology of the anorectal region are understood.

Anorectal functional results after transanal endoscopic microsurgery in benign and early malignant tumors

BACKGROUND

Transanal endoscopic microsurgery (TEM) has been suggested as a minimally invasive procedure of low morbidity for rectal villous adenomas and early anorectal adenocarcinomas. It has been used clinically in many areas outside of China for more than 20 years, but it began in mainland China only about 2 years ago. Some articles have reported excellent results with regard to morbidity and relapse rate with TEM, but there are no studies addressing its functional results in China until now. The aim of the present study was to analyze the effect of TEM on the manometric results.

METHODS

Thirty-seven patients (16 females, 21 males) underwent TEM and were followed for more than 6 months. Anorectal manometry and an incontinence questionnaire were administered 1 week preoperatively, 2 weeks postoperatively, 3 and 6 months postoperatively.

RESULTS

Of the 37 patients, 24 had villous adenomas and 13 had adenocarcinomas (11 uT1 and 2 uT2). Anorectal manometric values showed the mean anal resting pressure (ARP) decrease from 45 +/- 6 mmHg to 29 +/- 4 mmHg (p < 0.05) and the maximum tolerable volume (MTV) decrease from 175 +/- 21 ml to 90 +/- 15 ml (p < 0.05) at the third month after TEM. Maximal squeeze pressure (MSP) decreased from 181 +/- 20 mmHg to 92 +/- 14 mmHg (p < 0.05) at second week after operation and returned to normal value by the third postoperative month. The ARP and MTV were 45 +/- 5 mmHg and 177 +/- 21 ml, respectively, at 6 months after TEM, near the normal value (p > 0.05). Rectoanal inhibitory reflex (RAIR) was absent preoperatively in two patients; it was also absent in 10 patients 3 months postoperatively and in three patients 6 months postoperatively. Endosonography demonstrated internal anal sphincter (IAS) rupture in five patients, and full integrity of the external anal sphincter (EAS) in all patients. Of the five patients with IAS rupture, four had temporary incontinence to flatus normalized up to three postoperative months. Most patients had more times of stools per day and relative higher Wexner scores in a short period after TEM. All these patients were followed for 6-20 months with no incidence of relapse.

CONCLUSIONS

Anorectal function was preserved well after TEM, although some anorectal manometric parameters changed over time. Thus TEM is safe, in terms of anorectal function, for the cure of benign and early malignant tumors of the rectum.

Evaluation of anal incontinence: minimal approach, maximal effectiveness

Anal incontinence is a symptom represented by the impaired ability to control the elimination of gas and stool, with an estimated incidence of 2.2 to 7.1% of the population. These numbers likely under-represent the true prevalence because physicians and patients are reluctant to discuss this problem. Evaluation of the patient with anal incontinence requires a fundamental knowledge of the etiologic factors. Careful history and physical examination is essential in every patient and can identify the cause of most cases of incontinence. Incontinence scoring systems are tools that provide objective data regarding the severity and quality of anal incontinence. Supplemental special tests for evaluating incontinence should be aimed at achieving three goals: (1) provide additional and confirmatory information regarding the diagnosis and cause of incontinence; (2) select appropriate treatment; and (3) predict treatment outcome. Numerous studies to evaluate anal incontinence exist; however, the most useful tests to achieve these goals are anal manometry, pudendal nerve terminal motor latency, and anal endosonography, because these studies can identify physiologic, neurologic, and anatomic abnormalities of the anorectum for which there may be effective treatments.

Transcutaneous needle-free injection of botulinum toxin: a novel treatment of childhood constipation and anal fissure

PURPOSE

Constipation is a common problem in children, and when it becomes chronic fecal impaction, overflow soiling and megarectum may develop. Children with chronic idiopathic constipation (IC) may not respond to conventional treatments of laxatives, enemas, and toilet training. The aims of the study were to evaluate the long-term outcome of transcutaneous needle-free injection of botulinum toxin (TNFBT) into the external anal sphincter (EAS) and to assess the extent of the toxin penetration into the sphincter.

METHOD

Children were recruited if symptomatic with chronic constipation, soiling, painful defecation, and withholding behavior requiring disimpaction of stool and rectal biopsy under general anesthesia. A total dose of 200 U of botulinum toxin (BT) (Dysport; Ipsen Limited, Slough, United Kingdom) was injected transcutaneously into the EAS at 3 and 9-o'clock positions using J-tip needle-free syringes (National Medical Products Inc, Irvine, Calif). The depth and width of toxin penetration was assessed by endosonography. Outcome was measured by a validated symptom severity (SS) score questionnaire. The total SS score ranged between 0 (best) and 65 (worst). The outcome was compared with 31 children in a comparable historical control group at 3 and 12-month follow-up.

RESULTS

Sixteen children were recruited with median age of 6.11 (range, 3-14.85) years and median duration of symptoms of 3.9 years (1.6-11.5). On endosonography, the median depth and width of BT penetration was 8 (7-10) mm and 8 (6-10) mm, respectively. At 3-month follow-up, the median SS score improved in all children after TNFBT from 32.50 (5-57) to 7.50 (0-26) (Wilcoxon's P < .0001). There were significant improvements in symptoms of constipation, soiling, painful defecation, general health and behavior, and fecal impaction of rectum (P < .05). Anal fissures healed in all 4 children. The SS score in the control group improved from 33 (12-49) to 15 (0-40) (P < .0001). At 12-month follow-up, the improvement of SS score in TNFBT group was significantly more than the control group as follows: 4 (0-25) vs 15 (0-51), respectively (Mann-Whitney U P < .002). Three patients had a second TNFBT injection for relapsed symptoms. There were no complications. The transcutaneous needle-free injection of botulinum toxin eliminates the risk of intravascular injection or needlestick injury. The transcutaneous needle-free injection of botulinum toxin also has other therapeutic applications including an alternative therapy to biofeedback training for dyssynergia of the EAS, treatment of muscle limb spasticity in cerebral palsy, and cosmetic treatment of overactive facial muscles and wrinkles and hyperhydrosis.

CONCLUSION

Transcutaneous needle-free injection of botulinum toxin into the external anal sphincter is a novel and safe new treatment of chronic idiopathic constipation and anal fissure in children. A second injection may be required in 20% of patients.

Comparison between perfusion and balloon techniques for performing anorectal manometry in children with intestinal constipation

INTRODUCTION

Two anorectal manometry techniques have commonly been utilized: the perfusion technique and the balloon technique.

PURPOSE

To compare both techniques in children with intestinal constipation who had not undergone surgical treatment for its correction.

METHODS

Thirty-nine children aged between four and fourteen years underwent anorectal manometry using both techniques at random. Resting pressure, pressure response to voluntary contraction, coughing and perianal stimulation, maximum pressure on the anal canal pressure curve, and presence of rectosphincteric reflex were registered and submitted to statistics. Vectorgraphy of the sphincter muscle complex was obtained by perfusion technique.

RESULTS

The statistical comparison between the techniques revealed statistically significant differences in resting pressure (p=0.041), pressure response to voluntary contraction (p=0.026) and maximum pressure within the pressure curve (p=0.010). The rectosphincteric reflex was demonstrated in 21 patients by both techniques.

CONCLUSIONS

The perfusion technique presented greater sensitivity in the following parameters: resting pressure, pressure response to voluntary contraction and maximum pressure within the pressure curve. The methods studied are equivalent regarding the measurement of pressure responses to coughing and perianal stimulation and the investigation of rectosphincteric reflex.

Pelvic floor anatomy and applied physiology

Pelvic floor muscles have two major functions: they provide support or act as a floor for the abdominal viscera including the rectum; and they provide a constrictor or continence mechanism to the urethral, anal, and vaginal orifices (in females). This article discusses the relevance of pelvic floor to the anal opening and closure function, and discusses new findings with regards to the role of these muscles in the vaginal and urethra closure mechanisms.

Length-tension relationship of the external anal sphincter muscle: implications for the anal canal function

The length at which a muscle operates in vivo (operational length) and the length at which it generates maximal force (optimal length) may be quite different. We studied active and passive length-tension characteristics of external anal sphincter (EAS) in vivo and in vitro to determine the optimal and operational length of rabbit EAS. For the in vitro studies, rings of EAS (n = 4) were prepared and studied in a muscle bath under isometric conditions. For in vivo studies, female rabbits (n = 19) were anesthetized and anal canal pressure was recorded by use of a sleeve sensor placed in the custom-designed catheter holders of 4.5-, 6-, and 9-mm diameters. Measurements were obtained at rest and during EAS electrical stimulation. Sarcomere length of EAS muscle was measured by laser diffraction technique with no probe and three probes in the anal canal. In vitro studies revealed 2,054 mN/cm(2) active tension at optimal length. In vivo studies revealed a probe size-dependent increase in anal canal pressure and tension. Maximal increase in anal canal tension with stimulation was recorded with the 9-mm probe. Increases in anal canal tension with increase in probe size were completely abolished by pancuronium bromide. EAS muscle sarcomere length without and with 9-mm probe in the anal canal were 2.11 +/- 0.08 and 2.99 +/- 0.07 microm, respectively. Optimal sarcomere length, based on the thin filament length measured by thin filament analysis, is 2.44 +/- 0.10 microm. These data show that the operational length of EAS is significantly shorter than its optimal length. Our findings provide insight into EAS function and we propose the possibility of increasing anal canal pressure by surgical manipulation of the EAS sarcomere length.

Evaluation of outcome of anorectal anomaly in childhood: the role of anorectal manometry and endosonography

The aim of this study was to evaluate role of anorectal manometry (ARM) and anal endosonography (ES) in assessment of the internal anal sphincter (IAS) quality on continence outcome following repair of anorectal anomalies (ARA). We devised a scoring system to evaluate the quality of the IAS based on ARM and ES and correlated the scores with clinical outcome, using a modified Wingfield score (MWS) for faecal continence. We also assessed the implication of megarectum and neuropathy on faecal continence. Of 54 children studied, 34 had high ARA and 20 had low ARA. Children with high ARA had poor sphincters on ES and ARM, and also poor faecal continence compared to those with low ARA. The presence of megarectum and neuropathy was associated with uniformly poor outcome irrespective of the IAS quality. The correlations between MWS on one hand, and ES and ARM scores for IAS on the other hand were weak in the whole study group, ES r = 0.27, P < 0.04, and ARM r = 0.39, P < 0.004. However, the correlations were strong in those who had isolated ARA without megarectum or neuropathy, ES r = 0.51, P < 0.02 and ARM r = 0.55, P < 0.01, respectively. In conclusion, the ARM and ES are valuable in evaluation of continence outcome in children after surgery for ARA and those with good quality IAS had better faecal continence. The IAS is a vital component in functional outcome in absence of neuropathy and megarectum.

Impedance planimetric description of normal rectoanal motility in humans

PURPOSE

Manometry and pressure-volume measurements are commonly used to study anorectal physiology. However, the methods are limited by several sources of error. Recently, a new impedance planimetric system has been introduced in a porcine model. It allows simultaneous determination of anorectal pressures and multiple rectal luminal cross-sectional areas. This study was designed to study normal human rectoanal motility by means of impedance planimetry with multiple rectal cross-sectional areas and rectal and anal pressure.

METHODS

Twelve healthy volunteers (10 females), aged 24 to 53 years, were studied during one-hour fasting and one hour after a meal. Rectal cross-sectional areas were determined at five levels each 2 cm apart, as well as rectal and anal pressure.

RESULTS

A number of rectoanal motility patterns were observed. A total of 25 episodes with very localized cyclic rectal contractions detected at only one of five channels were observed lasting two to four minutes with a median frequency of three per minute (range, 2-6). A total of 44 episodes of cyclic rectal contractions propagating over two or more channels were detected lasting 2 to 36 minutes. Most were associated with contractions of the anal canal. A significant increase in rectal contractile activity was observed after the meal (P < 0.05). Single rectal contractions were observed in 11 subjects, and the majority were located to one channel and lasted less than 40 seconds. In two subjects who felt a need to defecate during the experiment, the cross-sectional area at all channels showed strong cyclic contractile activity and the anal pressure increased by approximately 100 percent.

CONCLUSIONS

The new rectal impedance planimetry system allows highly detailed description of rectoanal motility patterns. It has promise as a new method for description of rectoanal motility in further studies.

Elastomer implants in faecal incontinence: a blind, randomized placebo-controlled study

AIM

To test efficacy and safety of polydimethylsiloxane elastomer implants, a silicone biomaterial, in patients with severe faecal incontinence related to an impaired internal anal sphincter.

METHODS

Subjects were randomized to receive three injections of 2.5 mL of either physiological saline or polydimethylsiloxane elastomer. After local anaesthesia, an 18 gauge, 2.5-in needle was inserted through the perianal skin and laid down into the intersphincteric space. Treatment (saline or polydimethylsiloxane elastomer) was administered by means of a ratchet gun. Three injections of 2.5 mL each were performed in the area of the internal anal sphincter at 3, 7 and 11 o'clock positions. Main end point was the percentage of subjects in each treatment arm experiencing a successful treatment, defined as a Cleveland Clinic Florida-Faecal Incontinence score <8, 3 months after treatment. Secondary end points were quality of life scores, weekly number of faecal incontinence episodes, subject acceptance and adverse events rate. Both patients and end point assessments were blinded to treatment.

RESULTS

44 women (64.3 +/- 9 years) with a baseline Cleveland Clinic Florida-Faecal Incontinence score > or =8 were enrolled prospectively; 22 received polydimethylsiloxane elastomer and 22 saline treatment. Treatment was well tolerated. At 3 months, the percentage of subjects experiencing a successful treatment was not different between polydimethylsiloxane elastomer and saline groups (23% vs. 27%, respectively, P = 0.73). Moreover, Cleveland Clinic Florida-Faecal Incontinence score was not significantly different between polydimethylsiloxane elastomer and saline groups (11.7 +/- 4.7 vs. 11.4 +/- 4.5, respectively, P = 0.79).

CONCLUSIONS

Polydimethylsiloxane elastomer implants cannot be recommended for treatment of severe faecal incontinence related to impaired internal anal sphincter.

Botulinum toxin, a new treatment modality for chronic idiopathic constipation in children: long-term follow-up of a double-blind randomized trial

BACKGROUND

Myectomy of the internal anal sphincter (IAS) has been performed on some children after failure of medical treatment to treat idiopathic constipation. The aim of this study was to compare botulinum toxin injection with myectomy of the IAS in the treatment of chronic idiopathic constipation and soiling in children.

METHODS

This was a double-blind randomized trial. Patients between 4 and 16 years old were included in the study if they had failed to respond to laxative treatment and anal dilatation for chronic idiopathic constipation. All study patients had anorectal manometry and anal endosonography under ketamine anesthesia. Outcome was measured using a validated symptom severity (SS) scoring system, with scores ranging from 0 to 65.

RESULTS

Of 42 children, 21 were randomized to the botulinum group and 21 were randomized to the myectomy group. At the 3-month follow-up, the median preoperative SS score improved from 34 (range = 19-47) to 20 (range = 2-43) in the botulinum group (P < .001) and from 31 (range = 18-49) to 19 (range = 3-47) in the myectomy group (P < .002). At the 12-month follow-up, the scores were 19 (range = 0-45) and 14.5 (range = 0-41) for the botulinum group and the myectomy group, respectively (P < .0001). There was no complication in both groups.

CONCLUSION

Botulinum toxin is equally effective as and less invasive than myectomy of the IAS for chronic idiopathic constipation and fecal incontinence in children.

Effects of pelvic floor muscle contraction on anal canal pressure

The role of pelvic floor muscle contraction in the genesis of anal canal pressure is not clear. Recent studies have suggested that vaginal distension increases pelvic floor muscle contraction. We studied the effects of vaginal distension on anal canal pressure in 15 nullipara asymptomatic women. Anal pressure, rest, and squeeze were measured using station pull-through manometry techniques with no vaginal probe, a 10-mm vaginal probe, and a 25-mm vaginal probe in place. Rest and squeeze vaginal pressures were significantly higher when measured with the 25-mm probe compared with the 10-mm probe, suggesting that vaginal distension enhances pelvic floor contraction. In the presence of the 25-mm vaginal probe, rest and squeeze anal pressures in the proximal part of the anal canal were significantly higher compared with no vaginal probe or the 10-mm vaginal probe. On the other hand, distal anal pressures were not affected by any of the vaginal probes. Ultrasound imaging of the pelvic floor revealed that vaginal distension increased the anterior-posterior length of the puborectalis muscle. Atropine at 15 micro g/kg had no influence on the rest and squeeze anal pressures with or without vaginal distension. Our data suggest that pelvic floor contractions increase pressures in the proximal part of the anal canal, which is anatomically surrounded by the puborectalis muscle. We propose that pelvic floor contraction plays an important role in the fecal continence mechanism by increasing anal canal pressure.

Outcome of excision of megarectum in children with anorectal malformation

BACKGROUND/PURPOSE

Megarectum in association with anorectal malformation contributes to chronic constipation and fecal incontinence. Resection of megarectum in anorectal malformation improves bowel function, but neuropathy and poor sphincter quality may affect the outcome of fecal continence adversely. The aim of this study was to evaluate the benefits of resection of megarectum in anorectal malformation and to ascertain the impact of anal sphincter quality and neuropathy on the outcome.

METHODS

We studied 62 children with intractable fecal incontinence after repair of anorectal malformation between January 1991 and January 2005. All patients were investigated with anorectal manometry and anal endosonography under ketamine anesthesia. On endosonography, an intact or scarred internal anal sphincter (IAS) was classified as good and a fragmented or absent IAS as poor. On manometry, a resting anal sphincter pressure equal to or more than 30 mm Hg was classified as good and a lower pressure as poor. Functional assessment of fecal continence was done before and after excision of megarectum using a modified Wingfield scores.

RESULTS

Sixteen children had excision of megarectum with median age of 9 years (range, 2-15 years) and postoperative follow-up of 5 years (range, 1-10 years). Seven had formation of antegrade continent enema stoma before excision of megarectum. Children were classified into three groups of anomalies: low (n = 6), intermediate (n = 4), and high (n = 6). All children were incontinent of feces. After excision of megarectum, of the 9 children with good IAS and no neuropathy, 7 became continent of feces. Of the remaining 7 children, 4 had poor IAS and 3 had neuropathy, 5 of whom required an antegrade continent enema stoma to be clean.

CONCLUSION

Excision of megarectum in children who had previous repair of anorectal malformation results in fecal continence in the presence of a good IAS and absence of neuropathy. Patients with a poor IAS or neuropathy will often require artificial means of fecal continence.

Functional correlates of anal canal anatomy: puborectalis muscle and anal canal pressure

BACKGROUND

Resting and squeeze pressures in the anal canal are thought to reflect the contributions of the internal anal sphincter (IAS) and the external anal sphincter (EAS) respectively. Role of the puborectalis muscle (PRM) in the genesis of anal canal pressure is not known.

OBJECTIVES

To determine the functional correlates of anal canal anatomy.

METHODS

Seventeen asymptomatic nulliparous women were studied using simultaneous 3D ultrasound images and manometry of the anal canal. Ultrasound images were recorded using a transducer placed at the vaginal introitus and pressures were recorded with a side-hole manometry catheter using a station (every 5 mm) pull-through technique. Pressures were recorded at rest and during voluntary squeeze.

RESULTS

Anal canal high pressure zone was 39 +/- 1 mm in length. The IAS, EAS, and PRM were clearly visualized in the ultrasound images. EAS was located in the distal (length 19 +/- 1 mm) and PRM in the proximal part (length 18 +/- 1 mm) of the anal canal. The station pull-through technique revealed increases in pressure with voluntary squeeze in the proximal as well as distal parts of the anal canal. Proximal anal canal pressure, located in the PRM zone, showed greater circumferential asymmetry than the distal anal canal pressure, located in the EAS zone.

CONCLUSIONS

(1) PRM contributes to the squeeze pressure in the proximal part of the anal canal and EAS to the distal anal canal. (2) PRM squeeze-related increase in anal canal pressure might be important in the anal continence mechanism.

Textbook Recommendations for Preventing and Treating Perineal Injury at Vaginal Delivery

OBJECTIVE

To assess general obstetrics textbooks regarding the quality and quantity of information about perineal injury at vaginal delivery.

METHODS

An obstetrics and gynecology resident, a perinatologist, and a urogynecologist evaluated 7 obstetrics textbooks by using a standardized abstraction form that delineated descriptions of anatomy and physiology, episiotomy use, and perineal trauma prevention and repair.

RESULTS

Two textbooks briefly described anal sphincter anatomy, but none provided a detailed discussion of the relative contribution of anatomic components to continence. Four textbooks discussed the evidence for and against midline or mediolateral episiotomy, and 6 advised against routine episiotomy. Six textbooks described grading lacerations, but only one described detailed repair techniques for all grades. Two textbooks discussed techniques to reduce perineal trauma at the time of delivery. Only one textbook discussed the need to reapproximate the normal anal sphincter anatomy during perineal repair.

CONCLUSION

Although most textbooks accurately reflect current literature regarding routine episiotomy, there is limited discussion of advantages and disadvantages of various types of episiotomy and little offered regarding prevention and repair of perineal trauma at delivery.

LEVEL OF EVIDENCE

III.

Sonographic investigation of the rectoanal inhibitory reflex: a qualitative pilot study in healthy females

PURPOSE

The rectoanal inhibitory reflex has been studied using various methods, e.g., anometry and electromyography. The aim of this study was to apply ultrasound for direct visualization of the rectoanal inhibitory reflex.

METHOD

The rectoanal inhibitory reflex was induced in ten healthy females (age range, 21-55 years) by injection of small amounts of water (7, 12, and 20 ml), into the rectum. The intra-anal pressure was measured with a microtransducer and the rectoanal inhibitory reflex was visualized with real-time transvaginal or transperineal sonography.

RESULTS

The rectoanal inhibitory reflex consisted of a reduction in the intra-anal pressure and relaxation of the internal anal sphincter, manifested as an increase in the inner diameter of the internal anal sphincter from the mean of 11 to 16 mm (P<0.001). Simultaneously, a wave of rectal contents entered the anal canal. The distance from the most distal border of the rectal contents to the anal verge decreased from a mean of 33 to 20 mm (P<0.001). The rectoanal inhibitory reflex ended with a retrograde transport returning anal contents into the rectum. During the retrograde transport a contraction in the internal anal sphincter was observed.

CONCLUSIONS

The rectoanal inhibitory reflex can readily be visualized with ultrasound as a wave of rectal contents entering the anal canal. The transport into the anal canal was not of voluntary origin and could be either noticed or not noticed by the subjects. The observed retrograde transportation in the anal canal was not noted by the subjects; it is related to a contraction in the internal anal sphincter and visualized for the first time using ultrasound.

Ano-rectal motility responses to pelvic, hypogastric and pudendal nerve stimulation in the Göttingen minipig

We investigated the effect of efferent stimulation of the pelvic (PN), hypogastric (HGN) and pudendal (PuN) nerves on ano-rectal motility in Göttingen minipigs using an impedance planimetry probe. Changes in the rectal cross-sectional area (CSA) at five axial positions and pressures in the rectum and anal canal were investigated simultaneously. Pelvic nerve stimulation elicited a CSA decrease in the proximal part of the rectum and a simultaneous CSA increase in its distal part. Anal pressure also decreased. Hypogastric nerve and PuN stimulation elicited an increase in anal pressure, but no rectal response. Severing the HGN produced a persistent reduction in resting anal pressure, but no change was observed when the PN and the PuN were severed. Stimulation of the distal part of all three nerves produced a persistent response. Administration of phentolamine and pancouronium eliminated the response to stimulation of the HGN and the PuN, respectively.

CONCLUSION

Rectal responses to PN stimulation vary more than previously suggested. The HGN has an excitatory effect on the internal anal sphincter, and the PuN on the external anal sphincter. However, the PuN plays no major role in maintaining basal anal pressure.

The internal anal sphincter: regulation of smooth muscle tone and relaxation

Basal tone in the internal anal sphincter (IAS) is primarily myogenic. Neurohumoral substances like angiotensin II may partially provide external signal for the basal tone in the IAS. The sphincteric relaxation on the contrary is neurogenic by activation of non-adrenergic non-cholinergic (NANC) nerves that release nitric oxide (NO), vasoactive intestinal polypeptide (VIP) and perhaps carbon monoxide. Because of the presence of spontaneous tone, the IAS offers an excellent model to investigate the nature of the inhibitory neurotransmission for NANC relaxation. Work from different laboratories in different species concludes that NO is the major contributor in the NANC relaxation. This may invoke the role of other inhibitory neurotransmitters such as VIP, working partly via NO. An understanding of the basic regulation of basal tone in the IAS and nature of inhibitory neurotransmission are critical in the pathophysiology and therapeutic potentials in the anorectal motility disorders.

Combined urinary and faecal incontinence

Combined urinary and faecal (liquid or solid) incontinence (double incontinence) is the most severe and debilitating manifestation of pelvic floor dysfunction. The community prevalence is 9-19% (urinary) and 5-10% (faecal), increasing with age. Pathophysiological factors include childbirth-associated external anal sphincter injury and pudendal nerve damage, pelvic floor descent, menopause, collagen disorders and multiple sclerosis-like conditions. The presence of crossed reflexes between the bladder, urethra, anorectum and pelvic floor in animal studies may explain the comorbidity of urinary and faecal urgency. Surgical treatment is based on aetiology and combined optimum techniques such as colposuspension or suburethral sling with overlapping sphincteroplasty. Other methods for improving sphincteric control include sacral nerve neuromodulation, bulking agents and artificial sphincters.