External Anal Sphincter Injury Research Articles

The effect of Trolox on the rabbit anal sphincterotomy repair

IntroductionFecal incontinence (FI) is caused by external anal sphincter injury. Vitamin E is a potential strategy for anal sphincter muscle repair via its antioxidant, anti-inflammatory, anti-fibrotic, and protective properties against myocyte loss. Thus, we aimed to evaluate the water-soluble form of vitamin E efficacy in repairing anal sphincter muscle defects in rabbits.MethodsTwenty-one male rabbits were equally assigned to the intact (without any intervention), control (sphincterotomy), and Trolox (sphincterotomy + Trolox administration) groups. Ninety days after sphincterotomy, the resting and squeeze pressures were evaluated by manometry, and the number of motor units in the sphincterotomy site was calculated by electromyography. Also, the amount of muscle and collagen in the injury site was investigated by Mallory’s trichrome staining.ResultsNinety days after the intervention, the resting and squeeze pressures in the intact and Trolox groups were significantly higher than in the control group (P = 0.001). Moreover, the total collagen percentage of the sphincterotomy site was significantly lower in the Trolox group than in the control group (P = 0.002), and the total muscle percentage was significantly higher in the Trolox group compared to the control group (P = 0.001). Also, the motor unit number was higher in the Trolox group than in the control group (P = 0.001).ConclusionTrolox administration in the rabbit sphincterotomy model can decrease the amount of collagen and increase muscle, leading to improved anal sphincter electromyography and manometry results. Therefore, Trolox is a potential treatment strategy for FI.

Diagnostic approach to faecal incontinence: What test and when to perform?

Faecal incontinence (FI) is a debilitating common end result of several diseases affecting the quality of life and leading to patient disability, morbidity, and increased societal burden. Given the various causes of FI, it is important to assess and identify the underlying pathomechanisms. Several investigatory tools are available including high-resolution anorectal manometry, transrectal ultrasound, magnetic resonance imaging, and electromyography. This review article provides an overview on the causes and pathophysiology of FI and the author’s perspective of the stepwise investigation of patients with FI based on the available literature. Overall, high-resolution anorectal manometry should be the first investigatory tool for FI, followed by either transrectal ultrasound or magnetic resonance imaging for anal internal sphincter and external anal sphincter injury, respectively.

Parturition mode recommendation and symptoms of pelvic floor disorders after obstetric anal sphincter injuries.

Our primary objective was to evaluate parturition mode (PM) recommendations following obstetric anal sphincter injuries (OASIs) and adherence to these recommendations and to evaluate recurrence of OASIs in women who had a subsequent vaginal delivery (VD). The hypothesis was that adherence to the PM recommendations leads to a reasonable OASI recurrence rate. This was a retrospective observational cohort study of patients with previous OASIs between 2010 and 2016. After an outpatient visit including 3D transperineal ultrasound to screen for pelvic floor and anal sphincter injuries, all patients received recommendations for a subsequent PM. Patients were invited to complete validated questionnaires 2 to 5years post-OASIs. The majority of invited patients (265/320) attended follow-up, with 264 receiving a recommendation for PM. Only 5.6% did not adhere to the received recommendation. One hundred sixty-one patients delivered again, 58% had a VD, and 42% had a cesarean section (CS). Recurrence of OASIs was observed in 4.3% of the patients that had a VD. Fecal incontinence occurred in 4.9%, however any form of anal incontinence in 48% of patients. While dyspareunia was common in patients with residual external anal sphincter (EAS) injuries and levator ani muscle (LAM) avulsions, anal pain occurred more frequently in EAS injuries and fecal incontinence in LAM avulsions. This study showed that the vast majority of patients followed PM recommendations, and this resulted in a low recurrence of OASIs with a high CS rate. Fecal incontinence after OASIs was correlated with the degree of OASIs.

Internal anal sphincter injury in the immediate postpartum period; Prevalence, risk factors and diagnostic methods in the Swedish perineal laceration registry

Risk factors for obstetric external anal sphincter injury are well known. Maternal and obstetric risk factors for internal anal sphincter injury are not extensively studied.The rationale of this study was to evaluate the proportion of internal anal sphincter injury in women with external anal sphincter injury, diagnosed immediately after delivery.This study will assess whether there are additional risks for obstetric internal anal sphincter injury. ObjectivesThe primary aim was to assess the proportion of internal anal sphincter injury immediately in women with an external sphincter injury and to evaluate maternal and obstetric risk factors for internal anal sphincter injury in women with an external anal sphincter injury only.A secondary aim was to relate the diagnostic methods used for obstetric perineal lacerations to the presence of an internal anal sphincter injury. Study DesignA registry study with data from the Swedish Perineal Laceration Registry 2014–2018.From the registry, the maternal and obstetric characteristics of 3,333 primiparous women with isolated external (N = 2,236) versus both external and internal (N = 1,097) anal sphincter injuries were studied, as were the methods used for examining the obstetric anal sphincter injuries. ResultsIn 32.9 % (1,097/3,333) of primiparous women with an external anal sphincter injury, an internal anal sphincter injury was diagnosed immediately after delivery. A perineal palpatory thickness of less than 10 mm was a diagnostic sign for internal sphincter injury. Well-known risk factors associated with obstetric anal sphincter injuries could not be confirmed as independent risk factors for internal sphincter injury. When the infant is born with an arm beside the head, there is an almost two-fold increased risk for internal sphincter injury. ConclusionsOur main finding is that 32.9 % of women with external anal sphincter injury also have an internal anal sphincter injury. A palpable perineal thickness of less than 10 mm, a degree 4-laceration and an infant born with a hand by the head increases the risk of internal sphincter injury and should be a clinical warning sign.

The impact of variations in obstetric practice on maternal birth trauma

Forceps delivery and length of second stage are risk factors of maternal birth trauma, i.e., levator ani muscle (LAM) avulsion and anal sphincter trauma. The cesarean section (CS) rate has recently become the key performance indicator because of its increase worldwide. Attempts to reduce CS rates seem to have led to an increase in forceps deliveries and longer second stages. This study aimed to determine the association between variations in obstetric practice (between hospitals) and maternal birth trauma. This was a retrospective ancillary analysis involving 660 nulliparous women carrying an uncomplicated singleton term pregnancy in a prospective perinatal intervention trial at two Australian tertiary obstetric units. They had been seen antenatally and at 3-6months postpartum for a standardized clinical assessment between 2007 and 2014. Primary outcome measures were sonographically diagnosed LAM and external anal sphincter (EAS) trauma. The incidence of LAM avulsion (11.5% vs. 21.3%, P = 0.01) and composite trauma, i.e., LAM avulsion ± EAS injury (29.2% vs. 39.7%, P = 0.03) were higher in one of the two hospitals, where the forceps delivery rate was also higher (10.9% vs. 2.6%, P < 0.001). BMI (OR 0.9, P = 0.02), length of second stage (OR 1.01, P = 0.02) and forceps delivery (OR 5.24, P < 0.001) were significant predictors of the difference in LAM avulsion incidence between the hospitals. Maternal age (OR 1.06, P < 0.04) and forceps delivery (OR 8.66, P < 0.001) were significant predictors for composite trauma. A higher incidence of LAM avulsion and composite trauma in one of the two hospitals was largely explained by a higher forceps delivery rate.

Anovaginal distance and obstetric anal sphincter injury: a prospective observational study

Introduction and HypothesisNo measurements are available for diagnosing the extent of obstetric lacerations. The primary aim of this study was to evaluate the relation between the anovaginal distance (AVD) measured with transperineal ultrasound immediately after delivery and external anal sphincter injury. A secondary aim was to assess whether the palpated perineal thickness was associated with the AVD.MethodsA prospective observational study of 150 primiparous women at the University Hospital, Linköping, Sweden. After vaginal delivery, initial inspection and palpation of the perineal thickness were performed by the midwife. The women were then divided into subgroups depending on the degree of the suspected perineal laceration. Transperineal ultrasound of the AVD was performed by a physician. Diagnostics of the perineal laceration were done according to standard care.ResultsWomen with an external sphincter injury had a shorter AVD and shorter palpatory perineal thickness compared with women without anal sphincter injury. No external sphincter injuries were diagnosed when the AVD and/or palpation height was > 20 mm. The mean AVD in the group with probable second-degree laceration (n = 85) was 18.8 mm (95% CI 17.8–19.8), in suspected third-degree laceration (n = 33) 15.7 mm (95% CI 13.7–17.7) and in probable third-degree laceration (n = 32) 11.8 mm (95% CI 9.7–13.9) (p < 0.001).ConclusionsA short AVD could be a warning sign postpartum and should increase the awareness of possible external sphincter injury before suturing. An AVD of 20 mm seems to indicate a cutoff level of the occurrence of external sphincter injury, but this needs further evaluation.

Clinical value of endoluminal ultrasonography in the diagnosis of rectovaginal fistula.

BackgroundRectovaginal fistula (RVF) refers to a pathological passage between the rectum and vagina, which is a public health challenge. This study was aimed to explore the clinical value of endoluminal biplane ultrasonography in the diagnosis of rectovaginal fistula (RVF).MethodsThirty inpatients and outpatients with suspected RVF from January 2006 to June 2013 were included in the study, among whom 28 underwent surgical repair. All 28 patients underwent preoperative endoluminal ultrasonography, and the obtained diagnostic results were compared with the corresponding surgical results.ResultsAll of the internal openings located at the anal canal and rectum of the 28 patients and confirmed during surgery were revealed by preoperative endosonography, which showed a positive predictive value of 100 %. Regarding the 30 internal openings located in the vagina during surgery, the positive predictive value of preoperative endosonography was 93 %. The six cases of simple fistulas confirmed during surgery were revealed by endosonography; for the 22 cases of complex fistula confirmed during surgery, the positive predictive value of endosonography was 90 %. Surgery confirmed 14 cases of anal fistula and 14 cases of RVF, whereas preoperative endoluminal ultrasonography suggested 16 cases of anal fistula and 12 cases of RVF, resulting in positive predictive values of 92.3 and 93 %, respectively.ConclusionThe use of endoluminal biplane ultrasonography in the diagnosis of RVF can accurately determine the internal openings in the rectum or vagina and can relatively accurately identify concomitant branches and abscesses located in the rectovaginal septum. Thus, it is a good imaging tool for examining internal and external anal sphincter injuries and provides useful information for preoperative preparation and postoperative evaluation.

The use of inflammation-related markers to predict outcome in rectal cancer

The use of inflammation-related markers to predict outcome in rectal cancer

Correlation of anorectal electromanometry and anorectal three-dimensional ultrasound findings in patients with fecal incontinence

ObjectiveTo show the correlation of anorectal electromanometry and three-dimensional anorectal ultrasonography in patients with fecal incontinence. MethodProspective study involving 34 women (mean age: 55 years) with a diagnosis of fecal incontinence. The samples were submitted to three-dimensional anorectal ultrasonography/Echodefecography and anorectal electromanometry. ResultsBased on anorectal electromanometry data, 70.5% of 34 patients had hypotonia at rest, 64.7% had hypotonic contraction, 52.9% had both hypotonia at rest and hypotonic contraction, and 44.1% had anismus. By three-dimensional anorectal ultrasonography, 32.3% had internal anal sphincter injury, 79.4% had external anal sphincter injures, and 26.4% had both internal and external anal sphincter injuries. In 38.2%, anismus was suggested and 50% showed rectocele. Overall, only 5.8% had normal results for anorectal electromanometry combined with three-dimensional anorectal ultrasonography. Kappa index was 0.297 and the presence of anismus through anorectal electromanometry and three-dimensional anorectal ultrasonography was compared by Student's t test application, with p<0.0001. ConclusionWe conclude that there was a reasonable agreement in the comparison of sphincter hypotonia by anorectal manometry and sphincter injury by anorectal three-dimensional ultrasonography in a group of patients with fecal incontinence. The incidence of anismus in patients with fecal incontinence is considerable, and the therapeutic approach in these patients should be modified.

Postpartum Incontinence. Narrative Review

The development of fecal incontinence after childbirth is a common event. This incontinence responds to a multifactorial etiology in which the most common element is external anal sphincter injury. There are several risk factors, and it is very important to know and avoid them. Sphincter injury may result from perineal tear or sometimes by incorrectly performing an episiotomy. It is very important to recognize the injury when it occurs and repair it properly. Pudendal nerve trauma may contribute to the effect of direct sphincter injury. Persistence of incontinence is common, even after sphincter repair. Surgical sphincteroplasty is the standard treatment of obstetric sphincter injuries; however, sacral or tibial electric stimulation therapies are being applied in patients with sphincter injuries not repaired with promising results.

Incontinencia fecal posparto. Revisión de conjunto

The development of fecal incontinence after childbirth is a common event. This incontinence responds to a multifactorial etiology in which the most common element is external anal sphincter injury. There are several risk factors, and it is very important to know and avoid them. Sphincter injury may result from perineal tear or sometimes by incorrectly performing an episiotomy. It is very important to recognize the injury when it occurs and repair it properly. Pudendal nerve trauma may contribute to the effect of direct sphincter injury. Persistence of incontinence is common, even after sphincter repair. Surgical sphincteroplasty is the standard treatment of obstetric sphincter injuries, however, sacral or tibial electric stimulation therapies are being applied in patients with sphincter injuries not repaired with promising results.

Experimental study of acellular dermal matrix biological patch enriched with bone marrow mesenchymal cells for the treatment of external anal sphincter injury

To investigate the feasibility of bone marrow mesenchymal stem cells(MSC)with the acellular dermal matrix(ADM) biological patch for the treatment of external anal sphincter injury on the animal models. Thirty Wistar rats with sphincter injury were randomly divided into three groups. Group A underwent end to end sphincteric repair directly, group B underwent end to end repair and then covered by ADM patch, and group C underwent end to end repair and then covered by ADM which was previously seeded with MSC. After six weeks, the whole ring specimens including anal canal and lower rectum were removed. The hematoxylin and eosin stain and Masson trichrome stain were performed to observe the change of histomorphology. Two weeks later, the majority of rat models presented with moist anus and crissum with loose stools, which indicated that the model was established successfully. Six weeks after repair, in group A and B, the suffusion of fibrous connective tissue and the infiltration of inflammatory cells were observed at the repair site of sphincter. And lots of collagen fiber which was stained into blue deposited dispersedly at the site of repair with no obvious proliferation of capillaries. However, in group C, the blue collagenous fiber which deposited at the sphincter injury site was less than that in groups A and B. Muscle fibers were observed to be stained into red distributed dispersedly at the repair site of sphincter in group C. Transplantation of ADM biological patch rich in bone MSC can partly improve the regeneration of rat injured anal sphincter and lessen the formation of cicatrix.

Correlation between levator ani muscle injuries on magnetic resonance imaging and fecal incontinence, pelvic organ prolapse, and urinary incontinence in primiparous women

The objective of the study was to correlate the presence of major levator ani muscle (LAM) injuries on magnetic resonance imaging (MRI) with fecal incontinence (FI), pelvic organ prolapse (POP), and urinary incontinence (UI) in primiparous women 6-12 months postpartum. A published scoring system was used to characterize LAM injuries on MRI dichotomously (MRI negative, no/mild vs MRI positive, major). Major LAM injuries were observed in 17 of 89 (19.1%) women who delivered vaginally with external anal sphincter (EAS) injuries, 3 of 88 (3.5%) who delivered vaginally without EAS injury, and 0 of 29 (0%) who delivered by cesarean section before labor (P=.0005). Among women with EAS injuries, those with major LAM injuries trended toward more FI, 35.3% vs 16.7% (P=.10) and POP, 35.3% vs 15.5% (P=.09), but not UI (P=1.0). These data support the growing body of literature suggesting that both EAS and LAM are important for fecal continence and that multiple injuries contribute to pelvic floor dysfunction.

The probability of finding nerve branches to the external anal sphincter

Normal defecation is a combination of several elements of reflex and voluntary functions. The issue of external anal sphincter innervation is of theoretical and clinical significance; however, literature on the subject is still scarce. Most study reports discuss the course of the pudendal nerve with no close insight into inferior rectal nerves supply to the external anal sphincter. We have not found any statistical "mapping" of the site of the nerve branches insertion into the external anal sphincter. Thus, the purpose of the present study was to determine the least and most typical location of nerve branches to the external anal sphincter. One hundred and ten pudendal nerve preparations were analysed. Following the dissection of the pudendal nerve and its branches, a beam compass was used to take linear measurements from the apex of the coccygeal bone to the point of nerve branch insertion to the external anal sphincter. The distance between coccygeal bone apex and the central tendon of the perineum was also measured. For the purpose of comparison, results are presented as relative Bi/A values. Computer programmes devised by the author of this paper within Turbo Pascal were then used to determine the probability of finding nerve branches to the external anal sphincter. Based on the analysis of 110 preparations of the pudendal nerve and its branches, one might conclude that the former was the main although not necessarily the only source of external anal sphincter innervation. While analysing the most and the least probable location of nerve branches to the external anal sphincter, the muscle length was expressed as percentage, i.e., 0% of sphincter length = the apex of the coccygeal bone; 100% of sphincter length = the central tendon of the perineum. The length was then divided into 5% intervals with the probability of finding nerve branches determined by programmes written in Pascal. Within 30-85% of external anal sphincter length, the probability of finding nerve branches to the external anal sphincter is greater than 0.3 with peak probability of 0.68 in the interval between 55 and 65%. Sphincter innervation and clinicoanatomical function of anal canal closure apparatus has been discussed with reference to external anal sphincter injury. Transcutaneous electrostimulation of the pudendal nerve and the use of anal canal electrodes have also been mentioned. The most probable location of nerve branches to the external anal sphincter is half way of its length, i.e., at hour 3 or 9 of the knee-elbow position or lithotomy position. The external anal sphincter can also be directly supplied by nerve branches originating from the sacral nerve root S4; the branches then go towards the posterior part of the sphincter.

Anterior anal fissures are associated with occult sphincter injury and abnormal sphincter function

The pathogenesis of chronic anal fissure (CAF) remains incompletely understood but most are associated with a high resting anal pressure and reduced perfusion at the fissure site. To date, no major distinction has been made between anterior and posterior anal fissures and their aetiology and treatment. We compared anterior and posterior fissures in patients who have failed to respond to medical treatment with respect to their underlying aetiology, anal canal pressures and sphincter muscle integrity. Seventy consecutive patients (54 female:16 male) with a symptomatic CAF and 39 normal controls (19 female:20 male) without evidence of significant ano-rectal pathology were prospectively assessed by manometry and anal endosonography. Anterior anal fissures were identified in a younger age group [33 years (IQR 26-37) vs 41 years (IQR 36-52)] and predominantly in women. Anterior fissure patients were significantly more likely to have underlying external anal sphincter defects compared with posterior fissures [OR 10.9 (95% CI 3.4-35.4)]. Maximum resting pressure was not significantly elevated for anterior fissures compared with controls (P = 0.316) but was significantly elevated in posterior fissures (P = 0.005). The maximum squeeze pressure was significantly lower in the anterior fissure group [167 cmH2O (IQR 126-196) vs 205 cmH2O (IQR 174-262), P = 0.004]. A history of obstetric trauma was significantly associated with anterior fissure location [OR 13.9 (95% CI 3.4-55.7)]. Anterior anal fissures are associated with occult external anal sphincter injury and impaired external anal sphincter function compared with posterior fissures. These findings have implications for treatment, especially if a definitive procedure, such as lateral internal sphincterotomy, is considered.

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.

Endoanal sonography in the assessment of perianal endometriosis with external anal sphincter involvement

Endoanal sonography can be used in the assessment of benign and malignant anal conditions and to evaluate the anatomy of the anal sphincters. We used endoanal sonography with a 10-MHz rotating endocavitary probe to evaluate a 45-year-old woman with a perianal mass, fecal incontinence, and menses-associated perianal pain. She had had 2 vaginal deliveries requiring episiotomies. Biopsy of the mass showed endometrial tissue. The ultrasound examination showed a perianal mass and an external anal sphincter injury. A wide excision and sphincteroplasty were performed, with improvement of fecal continence and pain. Histopathologic examination of the mass confirmed perianal endometrioma in an episiotomy scar.

Endosonographic evidence of injury to the internal anal sphincter after low anterior resection: long-term follow-up.

Transanal stapled anastomosis has been associated with continence disturbances and reduced postoperative anal sphincter function. The aim of the present work was to study the effect of transanal stapling on anal sphincter morphology by endoanal ultrasound. Thirty-nine consecutive patients undergoing stapled low anterior resection for rectal carcinoma were assessed. Each patient was assessed by endoluminal ultrasound before surgery, immediately after surgery, and at 3, 6, 9, 12, and 24 months after surgery. There were no preoperative internal anal sphincter defects observed. Three female patients were observed to have preoperative evidence of external anal sphincter defects. After low anterior resection, seven patients were found to have internal anal sphincter defects, which persisted after the two-year follow-up. There were no additional external anal sphincter injuries. Three patients with internal anal sphincter injuries required the use of pads for poor bowel function. Up to 18 percent of patients who underwent stapled low anterior resection had long-term evidence of internal anal sphincter injury. The external sphincter does not appear to be affected by the procedure.