Anal sphincter tears in patients with rectal prolapse and faecal incontinence

Objective Faecal incontinence often persists after surgery for rectal prolapse. Multiple mechanisms have been proposed as responsible, however, anal sphincter integrity has only been studied in a handful of cases. This study assesses the incidence of ultrasound detected anal sphincter tears in patients with rectal prolapse and faecal incontinence. Methods Retrospective search of medical records at Flinders Medical Centre over a 7‐year period to identify patients with full thickness rectal prolapse and faecal incontinence who had undergone endosonographical imaging of the anal sphincter complex. Anal manometry and pudendal nerve terminal motor latency studies were also included. Results Twenty‐one patients were identified (1 male, 20 female) of median age 67.5 years. Fifteen (71%) subjects had an abnormality in the anal sphincter complex on endoanal ultrasound. Of these, the defects in 4 (19%) patients were isolated to the internal sphincter, 3 (14%) to the external sphincter and in the remaining 8 (38%) subjects, defects were found in both internal and external sphincters. The degree of sphincteric defect was variable but at least 6 (29%) of the study group had full‐length external sphincter tears. In the 19 patients studied, anal manometry revealed reduced basal and squeeze pressures in the majority. Delayed pudendal nerve terminal motor latency was evident in 9 of 18 patients studied. Conclusion Anal sphincter tears are common in patients presenting with rectal prolapse and faecal incontinence. The faecal incontinence associated with prolapse appears to be multifactorial in aetiology. Anal sphincter defects are likely to contribute to persistent faecal incontinence or recurrence following rectal prolapse. Endoanal ultrasound derived knowledge of anal sphincter injury may guide surgical management in problematic cases.     

Assessment of sonographic quality of anal sphincter muscles in patients with faecal incontinence

Objective  The main application of endoanal ultrasonography (US) in evaluation of faecal incontinence is to identify surgically correctable sphincter defects. The aim of our study was to determine whether qualitative changes in echogenicity and in uniformity of internal (IAS) and external (EAS) anal sphincter muscles detected on endoanal US correlate with other anal laboratory tests and modified Wexner faecal incontinence functional score.
Method  Records on 99 patients having complete information on anorectal manometry, faecal incontinence scoring and available endoanal US imaging of the anal sphincters were included in statistical analysis. Anatomic appearance and changes in echogenicity of the anal sphincter muscles were recorded according to the proposed scoring system. Endoanal US defect and quality component scores for IAS and EAS as well as the total score were correlated with anal laboratory tests and incontinence score using Spearman's correlations test.
Results  There was a trend for correlation between IAS quality score and incontinence score ( P  = 0.06), but no correlation for IAS defect score. EAS defect score had a significant negative correlation with maximum squeeze pressure (MSP) ( P  = 0.031). Distal EAS quality score had a significant correlation with incontinence score ( P  = 0.002). EAS total score correlated with MSP ( P  = 0.02) and incontinence score ( P  = 0.006). Endoanal US total score was significantly correlated with incontinence score ( P  = 0.006), maximal resting (MRP) ( P  = 0.035) and MSP ( P  = 0.045) and high pressure anal canal zone length ( P  = 0.03).
Conclusion  Sonographic morphology of anal sphincter muscles correlates with anal laboratory tests and functional incontinence score. Qualitative ultrasound scoring instrument may improve evaluation of patients with faecal incontinence.     

Correlation between anal manometry and endosonography in females with faecal incontinence

Objective Female faecal incontinence (FI) is largely because of sphincter injury at childbirth. Sphincter assessment aims to identify surgically correctable defects. We aimed to identify endoanal ultrasonography (EAUS) parameters that correlate with sphincter function. Method One hundred females with FI and 28 healthy asymptomatic females were prospectively assessed. Wexner FI score was recorded and all subjects underwent anorectal manometry and EAUS. Multiple EAUS parameters were assessed and correlated with external (EAS) and internal (IAS) anal sphincter function, determined by maximum squeeze pressure (MSP) and maximum resting pressure (MRP) respectively. Parameters included sphincter quality (echogenicity), thickness, perineal body thickness (PBT) and defect characteristics (angle, length). Results are expressed as medians and interquartile range (IQR). Results Median Wexner score was 14 (12–17). Maximum EAS thickness significantly correlated with MSP (P = 0.019). EAS defects were detected in 84 patients and seven controls (P < 0.0001). Full‐length EAS defects were only detected in FI group and had significantly lower MSP [MSP mmHg: full length 85 (65–103) vs partial length 119 (75–155), P = 0.006]. FI patients were more likely to have a mixed echogenicity of EAS compared with controls. EAS ring quality, PBT and defect angle were not significant. IAS quality was significantly associated with MRP [MRP mmHg: uniform 62 (43–82) vs mixed 47 (30.5–57.5), P = 0.002]. Conclusion Certain EAUS parameters can be predictive of anal sphincter function. These include the presence of an EAS defect and its length, EAS maximum thickness, IAS ring quality. Integration of these parameters can give better EAUS correlation with manometry for FI evaluation.     

Is a morphologically intact anal sphincter necessary for success with sacral nerve modulation in patients with faecal incontinence?

Objective Sacral nerve modulation (SNM) for the treatment of faecal incontinence was originally performed in patients with an intact anal sphincter or after repair of a sphincter defect. There is evidence that SNM can be performed in patients with faecal incontinence and an anal sphincter defect. Method Two groups of patients were analysed retrospectively to determine whether SNM is as effective in patients with faecal incontinence associated with an anal sphincter defect as in those with a morphologically intact anal sphincter following anal repair (AR). Patients in group A had had an AR resulting in an intact anal sphincter ring. Group B included patients with a sphincter defect which was not primarily repaired. Both groups underwent SNM. All patients had undergone a test stimulation percutaneous nerve evaluation (PNE) followed by a subchronic test over 3 weeks. If the PNE was successful, a permanent SNM electrode was implanted. Follow‐up visits for the successfully permanent implanted patients were scheduled at 1, 3, 6 and 12 months and annually thereafter. Results Group A consisted of 20 (19 women) patients. Eighteen (90%) had a positive subchronic test stimulation. Twelve patients had a successful SNM implant during middle‐term follow‐up. Group B consisted of 20 women. The size of the defect in the anal sphincter varied between 17% and 33% of the anal circumference. Fourteen (70%) had a positive subchronic test stimulation. Twelve patients had a successful SNM implant during middle‐term follow‐up. In both groups, the mean number of incontinence episodes decreased significantly with SNM (test vs baseline: P = 0.0001, P = 0.0002). There was no significant difference in resting and squeeze pressures during SNM in group A, but in group B squeeze pressure had increased significantly at 24 months. Comparison of patient characteristics and outcome between groups A and B revealed no statistical differences. Conclusion A morphologically intact anal sphincter is not a prerequisite for success in the treatment of faecal incontinence with SNM. An anal sphincter defect of <33% of the circumference can be effectively treated primarily with SNM without repair.     

Anal sphincter defects and anal incontinence symptoms after repair of obstetric anal sphincter lacerations in primiparous women

A study was carried out to identify (1) incidence of anal incontinence symptoms, (2) incidence and size of both external anal sphincter (EAS) and internal anal sphincter (IAS) defects, and (3) relationship between anal incontinence symptoms and IAS or EAS defect size after repair of an obstetric anal sphincter laceration. Forty-seven vaginally primiparous women underwent obstetric anal sphincter laceration repair. At 8–12 weeks postpartum, anal incontinence symptoms were assessed, and endoanal ultrasound was performed. At 1–2 years postpartum, symptoms were reassesseds. The incidence of anal incontinence symptoms at 8–12 weeks was 43%. The incidence of IAS and EAS defects were 32% and 77%, respectively. IAS defects ≥45 degrees were predictive of symptoms (p = 0.02). After 18 months mean follow-up, 11% reported chronic symptoms. After anal sphincter laceration repair, anal incontinence symptoms occur in 43% of women and remain chronic in 11%. Anal incontinence symptoms are associated with increasing IAS defect size. Poster presentation at the American Urogynecologic Society Annual Meeting, Hollywood, Florida, USA, 27–29 September 2007.     

Sacral nerve stimulation in faecal incontinence associated with an anal sphincter lesion: a systematic review

Aim The long‐term results of sphincteroplasty for faecal incontinence due to an anal sphincter lesion have been disappointing. Initially sacral nerve stimulation was used only in faecal incontinence of neurogenic origin but subsequently the indications have been extended to other conditions. The aim of this review was to evaluate sacral nerve stimulation for incontinence in the presence of a sphincter defect. Method The MEDLINE, Embase and Cochrane Library databases for the period between 1995 and 2011 were searched for studies in English, with no limitations concerning the study size or the length of follow‐up. The major endpoints were clinical efficacy, changes in anorectal manometry and quality of life. Results Ten reports (119 patients) satisfied the inclusion criteria. The quality of the studies was low (nine were retrospective, one was prospective). All reported a lesion of the external anal and/or internal anal sphincter on endoanal ultrasound. A definitive implant was performed on 106 (89%) of the 119 patients who underwent a peripheral nerve evaluation test. The weighted average number of incontinent episodes per week decreased from 12.1 to 2.3, the weighted average Cleveland Clinic Score decreased from 16.5 to 3.8, and the ability to defer defaecation, when evaluated, increased significantly. The features at anorectal manometry did not change. The quality of life improved significantly in almost all studies. Conclusion Sacral nerve stimulation could be a therapeutic option for faecal incontinence in patients with an anal sphincter lesion. However, the quality of the published studies is low. A randomized clinical trial comparing sacral nerve stimulation with other classical surgical procedures at long‐term follow‐up, although beset with difficulties, should be conducted.     

Fatigue rate of the external anal sphincter

Aim Studies of skeletal muscle show that fatigue rate corresponds to the proportion of fast‐twitch and slow‐twitch fibres that are present in the muscle. Limited work has been done on the fatigue rate of the external anal sphincter. We have prospectively studied fatigability of the external anal sphincter in women with faecal incontinence and women with normal bowel control. Method Anorectal manometry was measured by a station‐pull technique using a water‐filled microballoon. Fatigue rate was calculated from anal pressure measurements taken every 0.1 s over a 20‐s squeeze. Results Women with faecal incontinence (n = 88, median ?12 cmH₂O/min) were less susceptible to fatigue than women with normal bowel control (n = 36, median ?43 cmH₂O/min) (P < 0.01). The external anal sphincter was less susceptible to fatigue with increasing age (P < 0.01, r = 0.499). In women with normal bowel control and in women with faecal incontinence fatigue rate was negatively correlated with maximum squeeze pressure (P < 0.01, r = ?0.287; P < 0.01, r = ?0.579). Conclusion The external anal sphincter was less susceptible to fatigue with increasing age. Women with faecal incontinence have a weaker but more fatigue‐resistant external anal sphincter. This might correspond to a higher proportion of slow‐twitch muscle fibres. Histological studies are needed to examine this hypothesis.     

Can anal manometry predict anal incontinence after fistulectomy in males?

BACKGROUND: Disordered continence is frequently reported after operations for anal fistulae and pre-operative anorectal physiology may be carried out prior to surgery to improve functional outcome. Elderly patients and multiparous females are at higher risk for incontinence, whereas males under 60 have stronger sphincters. The aim of this study was to investigate the predictive role of anal manometry and the causes of postoperative soiling and its effect on the quality of life in males with intact sphincters undergoing excision of either trans or supra sphincteric fistulae. METHODS: Thirty-eight patients (median age 47 years) were analysed retrospectively. None had previous anal surgery and all were fully continent. Five had Crohn's disease. Anal pressures and rectal sensation were evaluated prior to fistulectomy by means of anal manometry in all cases and after surgery in those who had postoperative incontinence. A cutting seton was used in 17 patients, a rectal advancement flap in 15 and a double rectal-cutaneous flap in six. None had a lay-open. The intersphincteric plane was explored and drained in all cases. A previously described incontinence grading and score was used to assess postoperative soiling. The median follow-up was 22 (range 5-89) months. The patients with postoperative anal incontinence were evaluated with the Gastrointestinal quality of Life Index Questionnaire (0:poor, 4:good) at a median follow-up of 49 months. RESULTS: Twenty-nine (76%) patients were continent after surgery, whereas 9 (24%) complained of some degree of anal incontinence (minor in 4, severe in 1, the 1-6 incontinence score being 3.7 +/- 1.3 (mean +/- s.d.m.). Their Quality of life score was 3.8 +/- 0.5 (mean +/- sdm). None of them had Crohn's disease, five had frequent diarrhoea, four had a reintervention for either anal fissure or recurrent fistula (two), three had a postseton anal deformity. No difference was found between continent and incontinent patients as far as pre-operative anal pressures were concerned, but the maximum rectal volume threshold was significantly higher in incontinent patients, 165 +/- 67 vs. 123 +/- 49 ml of air (P = 0.04). CONCLUSIONS: Sphincter division, diarrhoea and anal deformity may cause soiling after fistulectomy in males and it does not severely affect quality of life. Surgery rather than manometry may predict it and rectal sensation may play a role which needs further investigation.     

Selecting patients with faecal incontinence for anal sphincter surgery: the influence of irritable bowel syndrome

Aim This was a prospective study to determine the prevalence of irritable bowel syndrome (IBS) in patients with faecal incontinence and to investigate the association of IBS positivity with sphincter dysfunction. Method Patients with faecal incontinence were referred for physiological assessment and further management. Those with an acute obstetric injury, rectal prolapse or previous anorectal surgery were excluded. One hundred and seventy‐seven women were studied. Symptom questionnaires were used prospectively to identify IBS positivity using Rome 11 criteria and the Cleveland Clinic incontinence score. Results The prevalence of IBS was 44%. IBS patients had higher incontinence scores than non‐IBS patients (11.0 vs 9.0, P < 0.01). A normal or high maximum resting anal pressure in an incontinent woman increased the chance of her having IBS by a factor of 2.6. Conclusion The prevalence of IBS positivity in patients presenting with faecal incontinence was high. A normal or high anal resting pressure and a high incontinence score should raise the suspicion of IBS.     

The relationship between external anal and external urethral sphincter activity in continent women

The relationship between the external anal sphincter and the periurethral sphincter muscles is an unresolved issue. Recordings of the external anal sphincter (EAS) are commonly used to indicate the responses of the urethral sphincter during urodynamic evaluations and in biofeedback procedures for the treatment of urinary incontinence. This study examined the validity of using anal sphincter training to teach control of the external urethral sphincter. Subjects were 5 continent women, aged 37–51 years, who reported being free of all urologic symptoms. Using visual biofeedback of anal sphincter pressure, subjects were trained to voluntarily contract the sphincter to four amplitudes: 5, 10, 15, and 20 mmHg (6.8, 13.6, 20.4, and 27.2 cmH₂O). Then they were guided through a series of controlled anal sphincter contractions, while the response of the urethral sphincter was measured using surface electrodes embedded in a Foley catheter. At each of four bladder volumes, subjects performed 16 contractions (four contractions at each of the four amplitudes). The order of contractions was counterbalanced, using a Latin square design. The results show a strong, statistically significant, monotonic relationship between the magnitude of anal sphincter contraction (pressure) and the level of urethral sphincter electromyographic (EMG) activity. The results support the use of the external anal sphincter as an indicator of urethral sphincter activity for the purpose of conducting biofeedback in the treatment of urinary incontinence.     

A pilot study of ultrasound guided Durasphere injection in the treatment of faecal incontinence

Aim To assess injection of Durasphere under direct endoanal ultrasound guidance as a treatment for faecal incontinence. Method A total of 23 patients with varying degrees of persistent faecal leakage and/or soiling were recruited. Durasphere was injected in the intersphincteric plane under direct ultrasound guidance. All patients were given a general anaesthetic. Patients had ano‐rectal physiology, endoanal ultrasound, continence scoring and quality of life measures assessed at 0, 1, 3, 6 and 12 months. Results A total of 21 patients were followed up for at least 12 months, with two being excluded at the follow‐up stage. Friedman two‐way analysis of variance of the Cleveland Clinic Score, Faecal Incontinence Quality of Life Score and Diary Response Score demonstrated a significant sustained improvement. There was no significant improvement in number of bowel movements. There was a significant difference in anal squeeze pressure after therapy, but no significant difference in anal resting pressure. Six patients reported no improvement after Durasphere therapy. Conclusions Durasphere gave sustained improvements in quality of life and continence scores in this study group. Strict criteria are needed to ascertain suitability for Durasphere therapy.     

Effect of rectal distension on voluntary external anal sphincter function in healthy subjects

Aim Quantification of the anorectal reflex function is critical for explaining the physiological control of continence. Reflex external anal sphincter activity increases with rectal distension in a dynamic response. We hypothesized that rectal distension would similarly augment voluntary external anal sphincter function, quantified by measuring the anal maximum squeeze pressure. Method Fifty‐seven subjects (32 men, 25 women; median age 62 years), with normal anal canal manometry and endoanal ultrasound results, underwent a rectal barostat study with simultaneous anal manometry. Stepwise isovolumetric 50‐ml distensions (n = 35) or isobaric 4‐mmHg distensions (n = 22) above the minimum distending pressure were performed (up to 200 ml or 16 mmHg respectively), whilst anal resting pressure and maximum squeeze pressure were recorded and compared with the baseline pressure. Results The distension‐induced squeeze increment was calculated as the maximum percentage increase in maximum squeeze pressure with progressive rectal distension. This was observed in 53 of the 57 subjects as a mean ± standard deviation (range) increase of 32.8 ± 24.1 (?5.5 to 97.7)%. The mean ± standard deviation (range) distension‐induced squeeze increment in male subjects was 36.1 ± 25.7 (?5.5 to 97.7)% and in female subjects was 28.1 ± 20.1 (?3.8 to 70.2)%. There was no significant difference between the sexes (P = 0.194). Conclusion Rectal distension augments external anal sphincter function, confirming the existence of a dynamic rectoanal response. This may represent a quantifiable and important part of the continence mechanism.