Perineal examination as a predictor of underlying external anal sphincter damage

Anal incontinence and unrecognized anal sphincter injuries after vaginal delivery- a cross-sectional study in Norway

Background

Aim of the study was to estimate the prevalence of postpartum anal incontinence among women who delivered vaginally, and to assess the extent to which obstetric injuries to the anal sphincters are missed.

Methods

All women (both primiparous and multiparous) who delivered vaginally and received any kind of sutures in the perineal area at Innlandet Hospital Trust Elverum in Norway between January 1, 2015 and June 30, 2016 were invited to answer a questionnaire on St. Mark’s incontinence score and to participate in a clinical examination of the pelvic floor including endoanal sonography.

Results

In total 52,3% (n = 207) of the 396 invited women participated in the study. Mean St. Mark’s score was 1.8 points (95% CI 1.4 to 2.1) at examination 14 months (mean) postpartum, and none of the participants suffered from weekly fecal leakage. Fecal urgency affected 11.7% (95% CI 7.1 to 16.3) of the participants, and 8.7% (95%CI 5.1 to 12.8) had weekly involuntary leakage of flatus. Nine women (9.3%, 95% CI 4.1 to 15.5) had a previously undetected third degree obstetric anal sphincter injury.

Conclusion

The prevalence of anal incontinence among women who have delivered vaginally and received sutures due to 1st and 2nd degree perineal lacerations is low. Some obstetric anal sphincter injuries remain unrecognized at the time of delivery, but the symptoms of anal incontinence due to these injuries are in the lower half of the St. Mark’s incontinence score. Women with persistent symptoms like fecal urgency or leakage of gas and/or feces should be referred to evaluation by a colorectal surgeon in order to achieve optimal treatment.

Obstetrics anal sphincter injury and repair technique: a review

The Urogynecology Committee of the Asia and Oceania Federation of Obstetrics and Gynaecology (AOFOG) has held seminars and workshops on various urogynecological problems in each country in the Asia-Oceania area in order to encourage young obstetricians and gynecologists. In 2013, we organized the operative seminar for obstetrical anal sphincter injuries (OASIS) in which we prepared porcine models to educate young physicians in a hands-on workshop at the 23rd Asian and Oceanic Congress of Obstetrics and Gynaecology in Bangkok, Thailand. Laceration of the anal sphincter mostly occurs during vaginal delivery and it can develop into anal sphincter deficiency, which causes fecal incontinence, if an appropriate suture is not performed. OASIS has become an important issue, especially in developing countries. The prevalence of OASIS of more than the third degree is around 5% in primary parous women and the frequency is higher when detected by ultrasonographic evaluation. Several risk factors, such as macrosomia, instrumental labor, perineal episiotomy and high maternal age, have been recognized. In a society where pregnant women are getting older, OASIS is becoming a more serious issue. An intrapartum primary appropriate stitch is important, but the 1-year outcome of a delayed operation after 2 weeks postpartum is similar. A randomized controlled study showed that overlapping suture of the external sphincter is better than that of end-to-end surgical repair. The Urogynecology Committee of the AOFOG would like to continue with educative programs about the appropriate therapy for OASIS.

Current approach to episiotomy: Inevitable or unnecessary?

An episiotomy is a surgical incision through the perineum made to provide sufficient area for the delivery of the infant. About 10 to 95% of women who deliver will have episiotomy depending on which part of the world they are having delivery.

Too early episiotomy causes extensive bleeding and too late episiotomy causes the excessive stretching of a pelvic floor and lacerations could not be prevented.

According to widely accepted arguments, there are many benefits of episiotomy for the neonate: prevention of injuries, shoulder dystocia and mental retardation of the infant. Benefits for the mother are: reduction of severe lacerations, prevention of sexual dysfunction, prevention of urinary and fecal incontinence. But those things could also be complications of episiotomy, if it is being used nonrestrictively. Some other complications are also extensive bleeding, hematoma or infection.

There are many different opinions in literature about using episiotomy restrictively or routinely, so it is the right doubt arisen: is it inevitable or unnecessary?

There is a wide variation in episiotomy practice, and the decision of performing it or not depends of actual clinical situation.

There is still a great need for continuous obstetrics education according to the evidence based guidelines for the patient’s safety.

Obstetric anal sphincter injury: incidence, risk factors, and management

BACKGROUND AND AIMS

Obstetric sphincter damage is the most common cause of fecal incontinence in women. This review aimed to survey the literature, and reach a consensus, on its incidence, risk factors, and management.

METHOD

This systematic review identified relevant studies from the following sources: Medline, Cochrane database, cross referencing from identified articles, conference abstracts and proceedings, and guidelines published by the National Institute of Clinical Excellence (United Kingdom), Royal College of Obstetricians and Gynaecologists (United Kingdom), and American College of Obstetricians and Gynecologists.

RESULTS

A total of 451 articles and abstracts were reviewed. There was a wide variation in the reported incidence of anal sphincter muscle injury from childbirth, with the true incidence likely to be approximately 11% of postpartum women. Risk factors for injury included instrumental delivery, prolonged second stage of labor, birth weight greater than 4 kg, fetal occipitoposterior presentation, and episiotomy. First vaginal delivery, induction of labor, epidural anesthesia, early pushing, and active restraint of the fetal head during delivery may be associated with an increased risk of sphincter trauma. The majority of sphincter tears can be identified clinically by a suitably trained clinician. In those with recognized tears at the time of delivery repair should be performed using long-term absorbable sutures. Patients presenting later with fecal incontinence may be managed successfully using antidiarrheal drugs and biofeedback. In those who fail conservative treatment, and who have a substantial sphincter disruption, elective repair may be attempted. The results of primary and elective repair may deteriorate with time. Sacral nerve stimulation may be an appropriate alternative treatment modality.

CONCLUSIONS

Obstetric anal sphincter damage, and related fecal incontinence, are common. Risk factors for such trauma are well recognized, and should allow for reduction of injury by proactive management. Improved classification, recognition, and follow-up of at-risk patients should facilitate improved outcome. Further studies are required to determine optimal long-term management.

Effect of vaginal delivery on endosonographic anal sphincter morphology

OBJECTIVE

To describe the effect of vaginal delivery with no clinically recognized sphincter tear on endosonographic anal sphincter morphology and sphincter pressure and to relate endosonographic results to anal sphincter pressure and anal incontinence score.

STUDY DESIGN

Thirty-two nullipara underwent anal endosonography and anal manometry in the third trimester of pregnancy, 2 weeks and 6 months post-partum. The sphincter defect scores (1-16) and the thickness and length of the sphincters were measured by endosonography, and sphincter pressures and manometric sphincter lengths were determined. The Wexner incontinence score (1-20) was used to classify anal incontinence 6 months post-partum.

RESULTS

Five (16%) women had small endosonographic anal sphincter defects (score 3-4) before delivery. Eight women (25%; confidence interval 11-43%) had new defects detected post-partum, five small, one moderate (score 7), and two large (score 10-11). Six (75%) of eight women with new defects post-partum had undergone episiotomy versus five (21%) of 24 women with no new defects (p = 0.02). Six months after delivery 16 (50%) women reported anal incontinence, and there was a positive correlation between the endosonographic defect score 6 months post-partum and the Wexner incontinence score. The sphincter was significantly longer during pregnancy than 6 months post-partum.

CONCLUSION

New sphincter defects may arise after vaginal delivery without any clinically recognizable sphincter tear. There is a positive correlation between the endosonographic defect score 6 months post-partum and the Wexner incontinence score.

Anatomy and physiology of the female perineal body with relevance to obstetrical injury and repair

The female perineal body is a mass of interlocking muscular, fascial, and fibrous components lying between the vagina and anorectum. The perineal body is also an integral attachment point for components of the urinary and fecal continence mechanisms, which are commonly damaged during vaginal childbirth. Repair of injuries to the perineal body caused by spontaneous tears or episiotomy are topics too often neglected in medical education. This review presents the anatomy and physiology of the female perineal body, as well as clinical considerations for pelvic reconstructive surgery.

Investigation of faecal incontinence

Most patients with faecal incontinence require only a full history (information about other predisposing causes) and examination (assessment for faecal impaction and evaluation of sphincter function and structure). When necessary, anorectal physiological studies, endoanal ultrasound and magnetic resonance imaging allow accurate characterization of sphincter function and structure.

Anal function: effect of pregnancy and delivery

OBJECTIVE

To investigate the effect of pregnancy and delivery on anal continence, sensation, manometry, and sphincter integrity.

STUDY DESIGN

Two hundred eighty-six nulliparous women in the third trimester completed a symptom questionnaire and underwent anorectal sensation and manometric evaluations. Three months postpartum, 161 women returned and the questionnaires and investigations were repeated together with anal endosonographic examinations.

RESULTS

The prevalence of fecal urgency before, during, and after pregnancy was 1%, 9.4%, and 10.5%, respectively; the prevalence of anal incontinence before, during, and after pregnancy was 1.4%, 7.0%, and 8.7%, respectively. Vaginal delivery, particularly instrumental, resulted in a decrease in anal squeeze pressures (P =.015) and resting pressures (P =.002) but had no effect on anal sensation. Postpartum anal endosonographic examination revealed sphincter disruption in 38% of women. There was no relationship between symptoms and anal manometry, sensation, or sphincter integrity. Vaginal delivery (P <.0001) and perineal trauma (P <.001) were significantly associated with sphincter defects.

CONCLUSION

Vaginal delivery is associated with a decrease in anal pressures and increased anal sphincter trauma but has no effect on anal sensation. These changes were not related to anal symptoms.

Radiologic evaluation of anorectal disorders

Defecation is a dynamic event, and although evacuation proctography does not simulate physiologic defecation exactly, it does provide maximal stress to the pelvic floor and image rectal emptying, both of which are required for the diagnosis of certain conditions: MR imaging studies are attractive in that no ionizing radiation is involved, but unless an evacuation study is performed, the features of anismus, trapping in a rectocele, and intussusception cannot be diagnosed. Because these are the main reasons for investigating difficult defecation, the fluoroscopic examination is the simplest and most reliable method. Endoanal ultrasound is an ideal screening examination for incontinence to show internal sphincter degeneration and tears of the internal or external sphincters. The diagnosis of external sphincter atrophy on ultrasound is not yet resolved, and this remains an important indication for endoanal MR imaging.

Pelvic floor imaging

A greater awareness of the therapies now available for pelvic floor dysfunction has increased demand for specialized imaging of this region. Some of the techniques required are available at relatively few centers, and the purpose of this review is to introduce the emerging subspecialty of pelvic floor imaging to a more general readership. Pelvic floor anatomy is complex and is being unraveled by means of magnetic resonance (MR) imaging. This is discussed in detail by using a global, rather than a compartmentalized, anatomic approach. The physiology of normal urinary and anal function and the routine clinical tests applied to them are outlined. The imaging techniques involved include MR imaging, endosonography, and fluoroscopy. The main investigations include video urodynamic imaging, evacuation proctography, dynamic cystoproctography, dynamic MR imaging of the pelvic floor, and endoluminal imaging of the anal sphincters with MR imaging and ultrasonography. These are described in detail, and their role with regard to the main pathologic conditions of the pelvic floor--urinary and anal incontinence, constipation, and prolapse--are discussed.

The effects of childbirth on the pelvic-floor

Basically, vaginal delivery is associated with the risk of pelvic floor damage. The pelvic floor sequelae of childbirth includes anal incontinence, urinary incontinence and pelvic organ prolapse. Pathophysiology, incidence and risk factors for the development of the respective problems are reviewed. Where possible, recommendations for reducing the risk of pelvic floor damage are given.

Midline episiotomy and anal incontinence: retrospective cohort study

OBJECTIVE

To evaluate the relation between midline episiotomy and postpartum anal incontinence.

DESIGN

Retrospective cohort study with three study arms and six months of follow up.

SETTING

University teaching hospital.

PARTICIPANTS

Primiparous women who vaginally delivered a live full term, singleton baby between 1 August 1996 and 8 February 1997: 209 who received an episiotomy; 206 who did not receive an episiotomy but experienced a second, third, or fourth degree spontaneous perineal laceration; and 211 who experienced either no laceration or a first degree perineal laceration.

MAIN OUTCOME MEASURES

Self reported faecal and flatus incontinence at three and six months postpartum.

RESULTS

Women who had episiotomies had a higher risk of faecal incontinence at three (odds ratio 5.5, 95% confidence interval 1.8 to 16.2) and six (3.7, 0.9 to 15.6) months postpartum compared with women with an intact perineum. Compared with women with a spontaneous laceration, episiotomy tripled the risk of faecal incontinence at three months (95% confidence interval 1.3 to 7.9) and six months (0.7 to 11.2) postpartum, and doubled the risk of flatus incontinence at three months (1.3 to 3.4) and six months (1.2 to 3.7) postpartum. A non-extending episiotomy (that is, second degree surgical incision) tripled the risk of faecal incontinence (1.1 to 9.0) and nearly doubled the risk of flatus incontinence (1.0 to 3.0) at three months postpartum compared with women who had a second degree spontaneous tear. The effect of episiotomy was independent of maternal age, infant birth weight, duration of second stage of labour, use of obstetric instrumentation during delivery, and complications of labour.

CONCLUSIONS

Midline episiotomy is not effective in protecting the perineum and sphincters during childbirth and may impair anal continence.

Effect of delivery on anal sphincter morphology and function

PURPOSE

Anal sphincter injury is a serious complication of childbirth, which may result in persistent anal incontinence. Occult injuries, visualized with endoanal ultrasonography, have previously been reported in up to 35 percent of females in a British study. The aim of the present study was to study anal sphincter morphology and function before and after delivery in primiparous females in the United States.

METHODS

Thirty-eight primiparous patients (mean age, 31 years) were evaluated with endoanal ultrasonography, anal manometry, and pudendal nerve terminal motor latency during pregnancy and after delivery. Bowel function before and after delivery was recorded according to set questionnaires. Cesarean section was performed in three patients.

RESULTS

Clinical sphincter tears, requiring primary repair, occurred in 15 percent of the patients. After delivery endoanal ultrasonography revealed disruptions in the external anal sphincter in six patients, but no patient had disruption in the internal anal sphincter. One patient had slight scarring in the external sphincter. Of the seven patients with pathologic findings at endoanal ultrasonography, the left pudendal latency increased after delivery (P < 0.05), and manometric results were reduced. Three of these seven patients had a third-degree or fourth-degree tear during delivery. All investigations were normal in the three patients who underwent cesarean section.

CONCLUSIONS

The present study demonstrates a significant frequency of sphincter injuries (20 percent) after vaginal delivery. Obstetricians should be aware of this risk and explicitly inquire about incontinence symptoms at follow-up after delivery.

Changes in anal anatomy following vaginal delivery revealed by anal endosonography

OBJECTIVE

To investigate changes in anal canal anatomy following vaginal delivery in women without apparent sphincter injury.

DESIGN

Prospective controlled observational study.

SETTING

District general hospital.

POPULATION

Consecutive parous and nulliparous women attending a gynaecology outpatient clinic.

METHODS

All women were examined using anal endosonography, and parous subjects without apparent sphincter injury compared with age-matched nulliparous controls to determine any differences in general anal canal morphology.

MAIN OUTCOME MEASURES

Individual anal canal components were measured at defined levels and subjects compared with controls.

RESULTS

Twenty-one of 54 parous women had no anal sphincter scar. Compared with nulliparous women, they had significant anterior sphincter thinning (mean 3.7 mm vs 4.6 mm, P< 0.01) in association with lateral external sphincter thickening (mean 7.0 mm vs 4.4 mm, P<0.01), and longitudinal muscle thickening (mean 2.8 mm vs 2.1 mm, P< 001).

CONCLUSIONS

Specific changes in anal morphology have been demonstrated following vaginal delivery in women without apparent sphincter injury.