Early results of immediate repair of obstetric third-degree tears: 65% are completely asymptomatic despite persistent sphincter defects in 61%

OBJECTIVE: The outcome of immediate repair of obstetric third-degree tears is poorly documented. Immediate repair may give better functional results than delayed repair because scarring is reduced. This aim of this prospective study was to examine the early outcome of immediate repair of third-degree tears. METHOD: A total of 121 women who had immediate repair of obstetric third-degree tears underwent interview, anal ultrasonography and anorectal physiology. RESULTS: At review, 79 (65%) were completely asymptomatic (score = 0), 23 (19%), had minor flatus incontinence or mild urgency causing no compromise to their quality of life (score 1-4), and 19 (16%) had clinically embarrassing faecal incontinence (score 5-24). Thirty-nine (32%) had an intact internal anal sphincter (IAS) and external anal sphincter (EAS) (i.e. a successful repair), eight (7%) had a defect in the IAS alone but the EAS was intact (i.e. a successful repair but a residual IAS defect), 43 (35%) had a residual defect in the EAS alone (IAS intact) and 31 (26%) had a persistent defect in the IAS and EAS. Residual defects in either or both of the sphincters were associated with a significantly higher incidence of abnormal resting and squeeze anal pressures. Anal manometry had no correlation with symptoms. The highest proportion of severe incontinence was in those with an IAS defect alone (37%) and when there was a residual IAS and EAS defect (24%). Only 2 of 39 (5%) with an intact IAS and EAS had severe incontinence and only 8 of 43 (18%) with a residual EAS defect alone had severe faecal incontinence. CONCLUSION: These results indicate a good outcome following immediate repair of third-degree obstetric tears and emphasize the role of the IAS in providing continence.     

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.     

Outcome of obstetric anal sphincter injuries (OASIS)—role of structured management

Introduction and hypothesis  Prospective studies up to 1 year after repair of obstetric anal sphincter injuries (OASIS) report anal incontinence in 33% of women and up to 92% have a sonographic sphincter defect. The aim of this study is to determine the outcome of repair by doctors who have undergone structured training using a standardized protocol. Methods  Doctors repaired OASIS after attending a training workshop. The external anal sphincter was repaired by the end-to-end technique when partially divided and the overlap method when completely divided. Endoanal ultrasound was performed prior to suturing and 7 weeks later. A validated bowel symptom questionnaire was completed prior to delivery, at 7 weeks postpartum, and at 1 year postpartum. Results  Fifty-nine women sustained OASIS. At 7 weeks, six (10%) had a defect on ultrasound. There was no significant deterioration in symptoms of fecal urgency, incontinence, or quality of life at 1 year after delivery. Conclusions  The 1-year outcome after repair of OASIS appears to be good when repaired by doctors after structured training.     

Importance of evacuatory disturbance in evaluation of faecal incontinence after third degree obstetric tear

OBJECTIVE: To correlate anorectal function including rectal evacuation with anorectal physiology and endoanal ultrasound in women with third degree obstetric anal sphincter injury repaired at the time of delivery. PATIENTS AND METHODS: Forty-four women with repaired third degree tears underwent anorectal physiology, anal ultrasonography and clinical assessment using the St. Marks incontinence score (0-24). Evacuatory disturbance was assessed by questionnaire. RESULTS: There was a significant correlation between disturbed evacuation and incontinence symptoms (P=0.030). There was also a significant correlation between disturbed evacuation and internal anal sphincter (IAS) injury (P=0.026), but there was no correlation with external anal sphincter (EAS) injury. There was a correlation between disturbed evacuation and low resting anal pressure (P=0.013). Although IAS defects were associated with low anal pressure, only the correlation with Maximum Squeeze Pressure reached statistical significance (P=0.018). CONCLUSION: Women with evacuatory disturbance after repaired third degree tears have a greater level of incontinence than those whose emptying is normal. This association is related to internal sphincter injury and reduced anal sphincter pressures.     

Factors associated with anal sphincter laceration in 40,923 primiparous women

The objective of this study was to identify factors associated with anal sphincter laceration in primiparous women. A subpopulation of 40,923 primiparous women at term with complete data sets was abstracted from a state-wide perinatal database in Germany. Outcome variable was anal sphincter laceration. Independent variables were 17 known obstetrical risk factors/conditions/interventions impacting childbirth recorded on the perinatal data collection sheet. Cross table analysis followed by logistic regression analysis was used for data analysis. Logistic regression showed episiotomy (OR, 3.23; CI, 2.73–3.80) and forceps delivery (OR, 2.68, CI, 2.17–3.33) to be most strongly associated with anal sphincter laceration. Women with a BMI ≥ 30 kg/m², and smokers had a significantly lower risk of anal sphincter laceration. Local, pudendal, and epidural analgesia all reduced the risk of anal sphincter laceration. Iatrogenic factors most strongly associated with anal sphincter laceration in primiparous women include routine episiotomy and forceps delivery. This data was presented at the Annual Meeting of the International Urogynecological Association, August 9–12, 2005, Copenhagen, Denmark.     

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.     

External intercostal muscles and external anal sphincter electromyographic activity during coughing

Few studies focused on concomitant electromyographic recordings of pelvic floor muscles and muscles involved in cough initiation. The objective of this study was to investigate the temporal course of external anal sphincter activation during coughing. Informed consent was obtained from ten healthy volunteers and ten women presenting with stress urinary incontinence (SUI). Simultaneously, recordings of electromyographic activity of external intercostal muscles (EIC EMGi) and external anal sphincter (EAS EMGi) during coughing have been performed. It was chosen to study intercostals muscles because they are synchronous to diaphragmatic muscle during cough initiation. Median (interquartile range) latency between the onset of the EAS EMGi and the onset of the EIC EMGi was −210 ms (−398; −135) and 0 ms (−30; +111.7) in volunteers’ group and in SUI group, respectively (p = 0.0009). Abnormal temporal course of external anal sphincter activation is observed during coughing in women presenting with SUI compared to healthy volunteers.     

肛管内超声对排粪失禁患儿肛门括约肌受损程度的评价

目的探讨肛管内超声对肛门内括约肌（IAS）、肛门外括约肌（EAS）及耻骨直肠肌（PR）形态及完整性的评估,从而为排粪失禁的原因及治疗方案的制订提供客观依据。方法回顾性分析2009年12月至2012年11月间山东大学第二医院收治的14例先天性肛门直肠畸形术后及4例先天性巨结肠术后排粪失禁患儿的临床资料。应用肛管内超声对IAS、EAS及PR进行观察,并进行括约肌受损程度评分;同时行肛管直肠测压评分和肛门功能评分,通过Spearman秩相关分析评价括约肌评分与肛管直肠测压评分和肛门功能评分之间的相关性。结果18例患儿中男13例,女5例,年龄10—16岁。肛门括约肌受损评分结果显示,括约肌轻度受损11例,中度受损65J,重度受损1例;另有PR受损4例。括约肌评分与肛管直肠测压评分之间呈正相关（P〈0．05）,而与肛门功能评分无明显相关性（P〉0．05）。结论肛管内超声可清楚显示IAS、EAS和PR的形态,明确其是否完整及受损程度,是评价肛门直肠畸形术后排粪失禁患儿非常有价值的方法,但并不能完全反映括约肌及肛门的功能状况。     

Urinary incontinence after obstetric anal sphincter injuries (OASIS)—is there a relationship?

This study aimed to compare urinary symptoms and its impact on women’s quality of life after obstetric anal sphincter injuries (OASIS) with a matched control group in the short term. The study group consisted of 100 primiparous women with OASIS and 104 controls who sustained a second-degree tear or had a mediolateral episiotomy performed. All women completed a validated International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) questionnaire 10 weeks after delivery. Compared to controls, significantly more women with OASIS reported overall urinary incontinence (21.2 vs 38%, p = 0.005) and had significantly worse quality of life score (incontinence score: 2.42 vs 1.2; p = 0.008). Significantly more women with OASIS suffered from stress urinary incontinence (33 vs 14%; p = 0.002; OR 3.06; CI = 1.54–6.07) than controls. Logistic regression analysis revealed that OASIS and a prolonged (>50 min) second stage of labour were independent risk factors for the development of stress urinary incontinence. This study highlights the importance of inquiring about urinary incontinence in women with OASIS. Presented to the German Forum Urodynamicum 2006 by IS (11.03.2006) and received the Eugen-Rehfisch Award of the German Forum Urodynamicum.     

Translabial ultrasound assessment of the anal sphincter complex: normal measurements of the internal and external anal sphincters at the proximal,mid-, and distal levels

The purpose of this study was to measure the internal and external anal sphincters using translabial ultrasound (TLU) at the proximal, mid, and distal levels of the anal sphincter complex. The human review committee approval was obtained and all women gave written informed consent. Sixty women presenting for gynecologic ultrasound for symptoms other than pelvic organ prolapse or urinary or anal incontinence underwent TLU. Thirty-six (60%) were asymptomatic and intact, 13 symptomatic and intact, and 11 disrupted. Anterior–posterior diameters of the internal anal sphincter at all levels and the external anal sphincter at the distal level were measured in four quadrants. Mean sphincter measurements are given for symptomatic and asymptomatic intact women and are comparable to previously reported endoanal MRI and ultrasound measurements. Rebecca G. Rogers is a consultant for Pfizer.     

Internal anal sphincter: Clinical perspective

Objective

To summarise current knowledge of Internal anal sphincter.

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.     

Decreased rate of obstetrical anal sphincter laceration is associated with change in obstetric practice

A study was conducted to describe the rate of obstetrical anal sphincter laceration in a large cohort of women and to identify the characteristics associated with this complication. Data from all vaginal deliveries occurring between January 1996 and December 2004 at one institution were used to compare women with and without anal sphincter lacerations. Among 16,667 vaginal deliveries, 1,703 (10.2%) anal sphincter lacerations occurred. Regression models suggested that episiotomy (OR 1.36; 95% CI 1.16, 1.58), vacuum delivery (OR 3.19; 95% CI 2.69, 3.79), and forceps delivery (OR 2.79; 95% CI 1.94, 4.02) were each associated with the increased risk of anal sphincter laceration. Year of delivery was associated with a decreased risk of anal sphincter laceration (OR 0.94; 95% CI 0.92, 0.96) with the rate of laceration decreasing from 11.2% to 7.9% during the study period. Episiotomy and operative vaginal delivery are significant, modifiable risk factors. Changes in obstetric practice may have contributed to the dramatic reduction in anal sphincter laceration during the study period.     

Comparison of the main body of the external anal sphincter muscle cross-sectional area between women with and without prolapse

The aim of the study was to compare the main body of the external anal sphincter (EAS) cross-sectional area (CSA) of women with and without pelvic organ prolapse. Pelvic magnetic resonance imaging (MRI) scans of 40 women were selected for analysis. Of these women, 20 had pelvic organ prolapse and 20 had normal support. Of the women with normal support, 10 had known major levator ani (LA) muscle defects and 10 had normal LA muscles. The same was true for the women with pelvic prolapse: half had major LA defects and half had no LA defects. All patients had previously completed pelvic MRI in the supine position. 3-D models of the EAS were made and CSA of the EAS perpendicular to the fiber direction were measured circumferentially at 30° intervals. Univariable and multivariable analyses were performed. The mean CSA did not significantly differ between women with prolapse and normal support regardless of LA defect status (normal/−LA defect = 1.13 cm², prolapse/−LA defect = 0.86 cm², p = 0.065; normal/+LA defect = 1.08 cm², prolapse/+LA defect = 1.28 cm², p = 0.28). Women with prolapse and LA defects had a 49% larger mean muscle CSA compared to prolapse patients without LA defects (p = 0.01). This difference associated with defect status in prolapse patients was not seen in women with normal support. Women with prolapse alone had external anal sphincter CSAs that were comparable to women with normal support. However, women with both prolapse and a major levator ani defect had larger external anal sphincter CSAs compared to prolapse patients without levator ani defects.     

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.     

Colorectal 25

Aims: To assess anal sphincter structure and functional outcomes following third-degree perineal tears and the effect of its disruption on the development of anal incontinence. Methods: Fifty-one consecutive patients, 41 primigravidae and 10 multigravidae, with third-degree intrapartum perineal tears, primarily repaired, were recruited 4 months postpartum. Patients completed questionnaires assessing faecal incontinence. Anal manometry and endosonography were then performed. Results: No patient reported incontinence prior to pregnancy. The incidence of faecal incontinence was 12 per cent. Six patients were incontinent of faeces and 10 incontinent of either flatus and/or fluid. Eighty-one per cent of anal incontinent patients were primigravidae (OR 0.96). Three women had previous third-degree tears, with one anal incontinence on subsequent delivery. Disruption of the external anal sphincter (EAS) was identified endosonographically in 26 patients. In 13 patients, there was an associated internal anal sphincter (IAS) defect. Clinically unsuspected tears of the Anal sphincter mechanism were diagnosed by anal endosonography in 46 per cent of asymptomatic patients. The EAS alone was involved in 14, IAS in three, and both in five patients. Clinical examination of women with anal incontinence identified an anal sphincter defect in 46 per cent. Ultrasound in anal incontinent patients showed an IAS defect in 42 per cent and an EAS defect in 52 per cent. All patients with faecal incontinence had a disruption of the EAS identified by endosonography (P < 0.05). No significant relationship was demonstrated between symptoms and anal manometry (P = 1.0, n.s.). Conclusions: Third-degree tears cause significant, although clinically unsuspected anal sphincter defects. It may be that anal manometry alone is not sufficient to exclude sphincter injury.     

Long‐term anal continence and quality of life following postpartum anal sphincter injury

Objective Anal incontinence occurs as a result of damage to pelvic floor and the anal sphincter. In women, vaginal delivery has been recognized as the primary cause. To date, figures quoted for overt third degree anal sphincter tear vary between 0% and 26.9% of all vaginal deliveries and the prevalence of anal incontinence following primary repair vary between 15% and 61%. Our aim was to analyse the long‐term (minimum 10 years post primary repair) anorectal function and quality of life in a cohort of women who suffered a third degree tear (Group 1) and compare the results with a cohort of women who underwent an uncomplicated vaginal delivery (Group 2) or an elective caesarean delivery (Group 3). Method In all, 107 patients who suffered a third degree tear between 1981 and 1993 were contacted with a validated questionnaire. The two control groups comprised of 125 patients in each category. Those who responded to the questionnaire were invited for anorectal physiology studies and endoanal ultrasound. Results Of the total number contacted, 54, 71 and 54 women from the three groups returned the completed questionnaire. In the three groups, a total of 28 (53%), 13 (19%) and six (11%) complained of anal incontinence (P < 0.0001) respectively. Comparison of quality of life scores between the groups showed a poorer quality of life in those who suffered a tear (P < 0.0001). In addition, in spite of primary repair, 13 (59%) patients in group 1 showed a persistent sphincter defect compared to one (4%) occult defect in Group 2 and none in Group 3. Conclusion Our study indicates that long‐term results of primary repair are not encouraging. It therefore emphasizes the importance of primary prevention and preventing further sphincter damage in those who have already suffered an injury (during subsequent deliveries).     

Artificial bowel sphincter in severe anal incontinence

OBJECTIVE: The artificial anal sphincter has been suggested as an alternative in the treatment of severe anal incontinence when conventional surgical methods are not possible or have failed. Experience in this procedure is still limited and the results have not yet been sufficiently established. The aim of this study is to evaluate the efficacy of the ACTICON (American Medical Systems, Minneapolis, MN) on patients operated upon in our Unit. PATIENTS AND METHOD: In this prospective study an ACTICON sphincter was implanted in 10 patients (8 women) with an average age of 56 years and with an average period of severe anal incontinence of 151 months. The origin of incontinence was obstetric injury (n: 4), neuropathy (n: 3) and sphincteral injury from previous anal surgery (n: 3). The degree of continence was measured using the Fecal Incontinence Scoring System (FISS) and the pre- and postoperative anal manometric parameters at 6-month intervals. The average follow-up time for the efficacy of the implanted system was 29 months. RESULTS: A total of 6 patients [60%] displayed complications in the immediate postoperative period: subaponeurotic reimplantation of the connecting tubes was necessary after infection of the abdominal wound (n:1); superficial dehiscence of the perianal wound (n: 2), infection of the perianal wound (n: 1) and perianal haematoma (n: 2) that were resolved by conservative treatment. For 3 patients [30%] the system was explanted, definitively in one and in 2 of them reimplanted successfully. At the end of the follow-up period, 9 patients [90%] still have an activated artificial sphincter. The score on the Fecal Incontinence System decreased significantly after the system was activated (P < 0.0001) and the pressure with the cuff closed was significantly higher than pre-operative anal pressure (P < 0.0001). All the patients are now continent for solid stool, 56% have occasional involuntary losses of gases and 33% occasionally have involuntary losses of gases and liquid stool. Only 2 patients [22%] have complete continence. CONCLUSIONS: Our findings indicate that the ACTICON artificial anal sphincter is well tolerated and can be an effective alternative in the treatment of severe anal incontinence. Although complete continence is only achieved in a low percentage of cases, for the rest of the patients the ACTICON neosphincter reduces the symptoms considerably.     

Towards safer treatments for benign anorectal disease: the pharmacological manipulation of the internal anal sphincter

INTRODUCTION

The internal anal sphincter (IAS) is an important structure that is responsible for the majority of resting tone of the sphincter complex. It has a central role in continence and damage to the muscle has serious implications. Injury is most frequently from obstetric trauma though iatrogenic injury from proctological surgery is also common. This review expands on how developments in understanding of the pharmacology of IAS might identify drug treatments as alternatives for proctological conditions such as anal fissure, avoiding the risk of sphincter injury. It also examines the role of pharmacology in treatment of those patients with established incontinence.

RESULTS

Much of the basic physiology and pharmacology of the IAS has been established through in vitro analysis, particularly in the superfusion organ bath. Further analysis has been undertaken using animal models such the pig. Clinical trials have established the efficacy of a number of agents for reducing IAS tone including glyceryl trinitrate and botulinum toxin. These drugs are probably safer, but less effective, than surgery for sphincter spasm, as is seen in anal fissure, though surgery alone or in combination with drug treatment may be appropriate for some patients. In vitro analysis and small-scale clinical trials suggest that phenylephrine and methoxamine may have a role in treating patients with incontinence primarily attributable to inadequate IAS function.

CONCLUSIONS

The pharmacology of IAS has been extensively studied in the laboratory, both in vitro and in animal models. In a short time, this laboratory work has been applied to clinical problems after testing in clinical trials. It is likely, however, that the best drugs and the optimal targets for manipulation have not yet been identified.     

Meta-analysis to determine the incidence of obstetric anal sphincter damage

BACKGROUND: The reported incidence of anal sphincter injury after first (11.5-35.0 per cent) and subsequent (3.4-12.1 per cent) vaginal deliveries varies widely. In addition, the reported incidence of associated faecal incontinence ranges from zero to 68.2 per cent. The aim of this study was to perform a meta-analysis of reported incidences of postpartum anal sphincter defect diagnosed by endoanal ultrasonography (EAUS) and associated incidences of faecal incontinence. METHODS: A Medline search yielded five studies with more than 100 subjects who underwent EAUS after childbirth for evaluation of anal sphincter disruption and who were questioned about symptoms of faecal incontinence, defined as any impairment in flatus and stool control but not including urgency of defaecation. A Bayesian meta-analysis was performed to produce one inference while accounting for potential heterogeneity among the five study populations. RESULTS: Meta-analysis of 717 vaginal deliveries revealed a 26.9 per cent incidence of anal sphincter defect in primiparous women and an 8.5 per cent incidence of new sphincter defects in multiparous women. Overall, 29.7 per cent of anal sphincter defects were symptomatic. Some 3.4 per cent of women experienced postpartum faecal incontinence without an anal sphincter defect. In a Bayesian calculation, the probability of postpartum faecal incontinence due to a sphincter defect was 76.8-82.8 per cent. CONCLUSION:: The incidence of occult anal sphincter disruption following vaginal delivery is much higher than commonly estimated. However, at least two-thirds of occult defects are asymptomatic postpartum. The probability of faecal incontinence associated with an anal sphincter defect was 76.8-82.8 per cent.