Sphincter Defects Research Articles

Beyond the numbers: Impact of obesity on obstetric anal sphincter injury (OASI) outcomes in women.

To compare the risk profiles, anatomical, and functional outcomes between obese and non-obese women who experienced obstetric anal sphincter injury (OASI). A retrospective electronic database study was conducted at Cork University Maternity Hospital (CUMH). Women with missing data/repairs conducted outside CUMH were excluded. Participants were categorized into obese (BMI ≥30 kg/m2) and non-obese (BMI <30 kg/m2) groups. Primary measure was a composite adverse outcome assessed 6 months post-delivery, including one or more of the following: resting pressure <40 mmHg, squeezing pressure <100 mmHg, defects in the internal and/or external anal sphincter. Statistical analyses were performed using SPSS version 28. Among the 349 women included in the study, 285 (81.7%) had a BMI <30 kg/m2 and 64 (18.3%) had a BMI ≥30 kg/m2. Gestational diabetes was significantly higher in obese women. No significant differences were observed in newborn weight or mode of delivery. The majority of tears were classified as grade 3B in both groups. Attendance rates at the OASI clinic did not differ between the groups. Among those attending, no statistical differences were noted in manometry results, which were reduced in both groups. Rates of internal anal sphincter defects were lower in the obese group (7.0% vs 15.6%, P = 0.15) and external anal sphincter defects were significantly lower in obese women (0% vs 9.1%, P = 0.04). No difference was found in the rates of composite adverse outcomes between the groups. Functional outcomes and manometry results did not differ, but non-obese women had higher rates of anatomical defects in OASI, requiring further study.

Pelvic Floor Ultrasound Findings and Symptoms of Pelvic Floor Dysfunction During Pregnancy.

Pregnancy and childbirth predispose to pelvic floor dysfunction (PFD), coinciding with functional and anatomical changes in the pelvic floor. To some extent, these can be assessed by transperineal ultrasound (TPUS), yet the correlation between ultrasound findings and symptoms has not been well elucidated. We hypothesised that pregnant women with PFD would show different findings at TPUS. This is a planned secondary analysis of a prospective cohort study. Pregnant women were asked to fill out standardised questionnaires on PFD and undergo TPUS at 12-14weeks and 28-32weeks of gestation. We compared bladder neck descent, urethral rotation, retrovesical angle, pelvic organ descent, genital hiatus dimensions and the presence of anal sphincter defects between women with and those without PFD using t test and Fisher's exact test. Linear mixed-effects models were used to assess the correlation between TPUS findings and PFD severity. As this is a secondary subgroup analysis of participants who underwent TPUS, no sample size was determined upfront. At Valsalva, women with urinary incontinence had more pronounced bladder neck descent (p = 0.02) and urethral rotation (p < 0.01), as well as wider retrovesical angles (p = 0.04) and larger genital hiatus areas (p < 0.01). After controlling for age, BMI and parity, the retrovesical angle was the only persistent predictor of urinary incontinence. No correlation was observed between any TPUS marker and symptoms of either prolapse or anorectal dysfunction. In pregnant women, symptoms of urinary incontinence, but not of prolapse and anorectal dysfunction, are associated with differences in pelvic floor anatomy at TPUS.

Rectovaginal fistulas : Differentiated diagnostics and treatment

Rectovaginal fistulas (RVF) represent less than 5% of anorectal fistulas. The classification of RVF is based on the localization (low vs. high) and the etiology. The most frequent causes of RVF are birth trauma, Crohn's disease, previous surgery and pelvic irradiation. In most cases a clinical diagnostic assessment is sufficient. Additionally, endosonography is areliable tool to detect sphincter defects. Computed tomography (CT) and magnetic resonance imaging (MRI) are reserved for special situations (e.g., RVF related to anastomotic leakage, after pelvic irradiation or associated with complex perianal fistulizing Crohn's disease). The surgical treatment is primarily oriented to the localization and etiology. Surgical techniques range from local procedures (e.g., endorectal advancement flap repair, transvaginal or transperineal closure) up to more invasive tissue interposition (e.g., bulbocavernosus muscle fat tissue flap or transposition of the gracilis muscle). In "high" RVF transabdominal approaches such as coloanal anastomosis, pull through procedures or omental interposition are indicated. All surgical procedures show high recurrence rates. Several operations are mostly necessary and a stoma creation is often required.

The Reliability of 3-Dimensional Endoanal Ultrasonography Early and Late Postpartum.

There is no consensus on how to define obstetric anal sphincter defects detected by 3-dimensional endoanal ultrasonography (3D-EAUS), and the reported rates vary significantly in the postpartum period. The objective of this study was to establish a diagnostic strategy with a high and clinically relevant interrater reliability both early and late postpartum. The study was prospective and observational, and 3D-EAUS was performed 10-14 days and 9-12 months postpartum in an unselected cohort of primiparous women with vacuum-assisted deliveries. Two experienced examiners evaluated the ultrasonographic results, which were divided into the categories intact, inconclusive, small, moderate, and large defects based on Starck scores. Three different diagnostic strategies were validated, and the prevalence- and bias-adjusted kappa (PABAK) values calculated. Of 334 eligible women, 184 (55.1%) completed both examinations. Disagreements involving small defects were predominant and observed in 34 and 39 cases, respectively, at the 2 time points. The highest overall agreement rates (91.3% and 92.4%, respectively) and PABAK values (0.83 and 0.85, respectively) were reached when the disagreements were minimized by dichotomizing the results into Starck scores >4 (designated a significant defect) versus Starck scores 0-4 (all others). The interrater reliability of detecting small anal sphincter defects by 3D-EAUS was low at both time points for the 2 experienced raters. In contrast, the interrater reliability of detecting a significant defect was classified as almost perfect agreement at both time points.

Comparative Study of Diluted Hydrogen Peroxide and Sulfur Hexafluoride in the Contrast-Enhanced Ultrasound Assessment of Anal Fistulas.

Endoanal ultrasound for the diagnosis of anal fistulas requires the injection of hydrogen peroxide, but it is often uncomfortable for the patient and possesses potential complications. Novel ultrasound contrast is currently available. We aimed to assess the efficacy and safety of sulfur hexafluoride as an ultrasound contrast agent for the diagnosis of perianal fistula by comparing it with those of 50% diluted hydrogen peroxide. Double-blind superiority study with 4 consecutive visits to perform an ultrasound without contrast, a hydrogen peroxide-enhanced ultrasound, a sulfur hexafluoride-enhanced ultrasound and a rectal exploration in the operating room (the gold standard). The ultrasound images were independently reviewed by three expert surgeon sonographers. This study was conducted at a single university hospital. Data from 176 patients were evaluated. Demographic and exploratory data and the ultrasound findings related to the location of the internal fistula orifice, description of the primary and secondary tracts, and presence of cavities and sphincter defects were analyzed. The complications occurring before and after the contrast agent administration and the presence of pain measured using a score were considered. Eighty-eight patients were included (men: 71.5%; mean age: 48.3 years).62.5% had a complex type and 83.7% had a transsphincteric type. Sulfur hexafluoride-enhanced ultrasounds demonstrated a higher interobserver agreement in determining the secondary tracts (κ= 0.604) and anal fistula height (κ=0.604) compared with other methods. Both hydrogen peroxide-enhanced ultrasound (90.91%) and sulfur hexafluoride-enhanced ultrasound (89.77%) detected the internal orifice more frequently than ultrasounds without contrast (62.5%) (p < 0.001),with no differences between contrast agents (p = 0.810). Sulfur hexafluoride-enhanced ultrasound were less painful than peroxide-enhanced ultrasound (p < 0.001). Most of the patients had transsphincteric anal fistulas. Sulfur hexafluoride proved comparable to hydrogen peroxide in evaluating fistulous tracts and identifying the internal orifice and additionally reduced significantly pain and discomfort. Furthermore, demonstrated a higher interobserver agreement in determining the secondary tracts and anal fistula height compared with other methods. See Video Abstract.

Cloacal Repair for Rectovaginal Fistula With Sphincter Defect.

Cloacal Repair for Rectovaginal Fistula With Sphincter Defect.

One-stage implant in sacral neuromodulation for faecal incontinence - short-term outcome from a prospective study.

Sacral neuromodulation (SNM) is approved for the treatment of faecal incontinence (FI) in a two-stage technique. With standardized implantation, approximately 90% of patients undergo successful Stage I operation and proceed to a permanent implant (Stage II). The aim of this work was to explore the feasibility of SNM as a one-stage procedure and report the 24-week efficacy. This study included patients diagnosed with idiopathic FI or FI due to an external anal sphincter defect ≤160° and one or more episodes of FI per week despite maximal conservative therapy. Patients were offered a one-stage procedure if a motor response of the external anal sphincter was achieved in three or more poles with at least one at ≤1.5 mA at lead placement. Patients were followed for 24 weeks. Their evaluation included the Wexner/St Mark's Incontinence Score, Faecal Incontinence Quality of Life score (FIQoL), a visual analogue scale (VAS) for assessing patient satisfaction and a bowel habit diary. Seventy-three patients with a median age of 60 years (interquartile range 50-69 years) completed this prospective study. Episodes of FI were significantly reduced at the 24-week follow-up, from 13 (8-23) at baseline to 2 (0-5) (p-value = 0002). A ≥50% reduction in the number of FI episodes was achieved in 92% of participants. The Wexner score improved significantly from 16 (14-17) at baseline to 9 (5-13) (p-value < 0.001), and the St Mark's score improved significantly from 18 (16-20) to 11 (7-16) (p-value < 0.001). All domains in the FIQoL score and VAS for patient satisfaction improved significantly following the one-stage procedure. A one-stage implantation procedure is feasible in selected patients with FI, significantly improving continence, quality of life and patient satisfaction after 24 weeks of follow-up.

A sensorised surgical glove to improve training and detection of obstetric anal sphincter injury: A preclinical study on a pig model.

To create a sensorised surgical glove that can accurately identify obstetric anal sphincter injury to facilitate timely repair, reduce complications and aid training. Proof-of-concept. Laboratory. Pig models. Flexible triboelectric pressure/force sensors were mounted onto the fingertips of a routine surgical glove. The sensors produce a current when rubbed on materials of different characteristics which can be analysed. A per rectum examination was performed on the intact sphincter of pig cadavers, analogous to routine examination for obstetric anal sphincter injuries postpartum. An anal sphincter defect was created by cutting through the vaginal mucosa and into the external anal sphincter using a scalpel. The sphincter was then re-examined. Data and signals were interpreted. Sensitivity and specificity of the glove in detecting anal sphincter injury. In all, 200 examinations were performed. The sensors detected anal sphincter injuries in a pig model with sensitivities between 98% and 100% and a specificity of 100%. The current produced when examining an intact sphincter and sphincter with a defect was significantly different (p < 0.001). In this preliminary study, the sensorised glove accurately detected anal sphincter injury in a pig model. Future plans include its clinical translation, starting with an in-human study on postpartum women, to determine whether it can accurately detect different types of obstetric anal sphincter injury invivo.

Irritable bowel syndrome worsens faecal incontinence after primary repair of major obstetric anal sphincter injuries.

Obstetric anal sphincter injuries (OASIS) occur in approximately 3%-6% of vaginal deliveries and are the leading risk factor for late-onset faecal incontinence, which is an underdiagnosed pathology. The aim of this work was to use a validated scoring system to quantify the effect of irritable bowel syndrome (IBS) on the severity of faecal incontinence symptoms after primary repair of major OASIS (Grade IIIb-IV). A prospective cohort study was performed on all women who underwent primary repair of major OASIS over a 6-year period. They were assessed with ultrasonography within 12 weeks. Two control groups (who did not have OASIS) were women who underwent elective caesarean section and primigravid women. Questionnaires were sent at least 12 months after delivery, or at first consultation for primigravids, which generated the main outcome measures: Cleveland Clinic faecal incontinence severity scores and the presence of IBS based on Rome III criteria. There was a total of 211 patients included in the three groups and the mean follow-up time was 26 months after sphincter repair. Ultrasonographic sphincter defects were detected in 37% but did not affect the faecal incontinence score (p = 0.47), except in patients with IBS. Within each group, patients with IBS had significantly worse faecal incontinence than those without. Women with both OASIS and IBS had the most severe faecal incontinence scores. OASIS has a limited negative effect on faecal incontinence, independent of whether residual ultrasonographic sphincter defects are present. However, the presence of IBS has a significant compounding effect on faecal incontinence in OASIS patients. The effect of IBS on faecal incontinence is also notable in caesarean section patients and primigravids, suggesting that IBS is an independent risk-factor that should have its place in predelivery assessment and counselling.

Gracilis Flap Restoring Quality of Life in a Patient with Non Functional Anal Sphincter

An excellent technique for reconstructing the perineum following extensive perineal resection for restoration of a traumatised anal sphincter is the Gracilis myocutaneous flap. Direct anal trauma or pelvic injuries can separate the anal sphincters. An overlapping sphincteroplasty has a fair possibility of regaining acceptable fecal continence if roughly half of the sphincter ring is still functional. A case of a 22-year-old male who underwent Gracilis myocutaneous flap reconstruction after being diagnosed with a non functioning anal sphincter is reported. A free muscle transplant was done to repair the sphincter, utilising denervated muscle with an intact blood supply. New muscle was attached to those sphincter muscles which were still functional. The transplanted muscle receives new muscular fibers, enabling the repaired sphincter to contract voluntarily in addition to reflexively. The surgical approach is determined based on the presented sphincter defect. Free muscle transplantation can be preferred in cases where the external sphincter has some degree of functionality.

Three-Dimensional Transperineal Ultrasound Guiding Early Secondary Repair of Obstetric Anal Sphincter Injury in an Incontinent Patient without Suture Dehiscence.

We present the case of a 36-year-old primigravida who gave birth to a 3200 g baby by vacuum-assisted (Kiwi OmniCup™) operative vaginal delivery with mediolateral episiotomy. A "y"-shaped perineal tear with a grade IIIC obstetric anal sphincter injury (OASI) was diagnosed and repaired. Two days after delivery, in the absence of suture dehiscence, she started experiencing complete anal incontinence. A decision was made in association with a proctologic surgeon for an early secondary repair. Before surgery, a Three-dimensional transperineal ultrasound (TPUS) was performed. The exam revealed a major defect of the external anal sphincter at the 11 o'clock position. This allowed for the reopening of only a circumscribed area of the perineal suture and repair of the sphincters using the end-to-end technique. The symptoms regressed completely, and follow-up TPUS demonstrated the gradual wound healing process. Anal incontinence, secondary to obstetric anal sphincter injury (OASI), has a severe negative impact on women's quality of life. TPUS is an effective method to detect sphincter defects and monitor the healing process. This report investigates the feasibility of identifying the sphincter tear in an incontinent puerperal patient without suture dehiscence in order to target early secondary repair while minimizing its extent. TPUS has proven a safe and effective tool to guide early secondary repair of symptomatic OASI complications while minimizing the invasiveness of the procedure. Multidisciplinary management is crucial to ensure the adequate standard of care.

Long-term outcome after SphinKeeper® surgery for treating fecal incontinence—who are good candidates?

PurposeThe efficacy of the novel SphinKeeper® procedure for the treatment of fecal incontinence (FI) is not yet well defined. This study aimed to assess long-term functional outcomes after SphinKeeper® surgery.MethodsWe included 32 patients with FI (28 female), who were operated at a tertiary referral center between August 2018 and September 2021. Functional outcome and quality of life were evaluated prospectively using validated questionnaires before and after surgery. Additionally, endoanal ultrasound and anal manometry were conducted prior and after SphinKeeper® implantation. Predictive parameters for treatment success were defined.ResultsThe mean follow-up time was 22.62 ± 8.82 months. The St. Mark’s incontinence score decreased significantly after surgery (median preoperative = 19 (IQR 17–22) versus median last follow-up = 12 (IQR 8–16), p = 0.001). Similarly, physical short-form health survey showed a significant improvement after SphinKeeper® implantation (p = 0.011).Patients with a higher degree of internal sphincter defect showed an improved objective therapy success (r = 0.633, p = 0.015) after SphinKeeper® operation, whereas the type and severity of FI had no impact on the functional outcome. Notably, a higher number of dislocated prostheses (r = 0.772, p = 0.015) showed a significant correlation with reduced improvement of incontinence.ConclusionThe SphinKeeper® procedure showed a significant long-term functional improvement in over half of the patients. Patients with a higher internal sphincter defect benefited most, whereas dislocation of the prostheses was associated with less favorable results.

OP15.01: Can we define a cut‐off for sphincter defect angle?

OP15.01: Can we define a cut‐off for sphincter defect angle?

Application of Kegel Gymnastics in Reducing Urinary Incontinence in the Elderly in Gampong Lamleuot, Kuta Cot Glie District, Aceh Besar

The elderly are someone who has reached the age of 60 years and over, where in old age a person has experienced various declines in system function, as well as changes in body structure, one of which is a change in the structure of the urinary system and has weakened pelvic floor muscles and decreased bladder capacity, so the elderly are very vulnerable to urinary incontinence. Urinary incontinence is a bladder sphincter defect or neurological dysfunction that causes loss of control over urination. Thus causing a person to experience physical, psychological, social, and economic problems that affect the quality of life of the elderly, one of the treatments for urinary incontinence in the elderly is by practicing Kegel exercises. The purpose of this study was to find out the picture of the application of Kegel exercises in reducing urinary incontinence in the elderly with urinary incontinence. This research method is a case study with 2 (two) research subjects, which was carried out in Gampong Lamleuot, Kuta Cot Glie District, Aceh Besar Regency on March 9-20, 2023. The instruments used are SOPs for Kegel exercises, observation sheets and Resived Urinary Incontinence Scale (RUIS) questionnaires. The results showed a decrease in the level of incontinence in the elderly after the application of Kegel exercises, thus it is hoped that elderly gymnastics can be used as one of the therapies in reducing the level of urinary incontinence in the elderly.

Indications and Results of Endoanal Ultrasonography in Anal Pathology

Anal disease encompasses a diverse array of disorders, including conditions such as sphincter defects, anorectal fistulas and abscesses, unexplained chronic anal pain. The objective of this study is to assess the diagnostic value of endoscopic ultrasound (EUS) in the context of anal diseases. A total of 58 patients who benefited from an EUS, over a period between January 2018 and april 2023. Mean age was 43,4 years with a sex ratio (M: F) of 0.4. The main indication for EUS is dominated by fecal incontinence (FI) in 53% of patients, followed by the anoperineal manifestations of Crohn's disease in 22%. Among patients with perineal Crohn's disease (CD), fistulas were observed in 47% of CD cases. anovaginal or rectovaginal fistulas (ARVFs) were visualized in 9% of all cases. In patients presenting with fecal incontinence (FI), EUS identified defects in the internal and external anal sphincters. EUS is a highly sensitive technique for assessing anal anatomy and diagnosing of anal diseases.

The Use of Sphinkeeper® In Faecal Incontinence

Introduction: Faecal Incontinence is a condition that can affect up to 20% of population during their lifetime with female predominance. Sacral Nerve Stimulation (SNS) has been recently shown to have significant benefits in mainly urge incontinence but this has left a large group of patients with passive incontinence without effective management options. The SphinKeeper® (SK) allows treatment of more sizeable defects in the internal or external anal sphincter. Preliminary series have shown some benefit of the procedure in treatment of faecal incontinence. Methods: A single-centre retrospective observational study of SphinKeeper® prostheses was conducted at St Helens and Knowsley NHS trust and we believe this to be one of the largest series of SphinKeeper® in the UK. SphinKeeper® restores sphincter function by using placement of self-expanding prostheses into the inter-sphincteric space. The operation involves implantation of 10 self-expanding sterile prostheses between the internal and the external sphincter, thus creating a third ring around the circumference of the anal canal. Results: Most patients were ASA 2 (n=10). 43% (6/14) patients had previous colorectal surgery – THD and mucopexy (n=3), anorectal fistula surgery (n=1), anterior resection of rectum (n=1) and pelvic floor repair (n=1). EUS was carried out in 6 patients and in all 6 cases identified internal or external anal sphincter defect (IAS n=1, EAS n=3, IAS and EAS n=2). No patient sustained intraoperative complications. 2 patients reattended within 48 hours post op due to severe post-operative pain and were discharged with analgesia. Subjective results were evaluated using Vaizey and Wexner scores and showed significant improvement 4/14 patients, partial improvement in 7/14 patients and no improvement in 3/14 patients. Discussion: Our study evaluated the short-term outcomes of the procedure in 14 patients who had SphinKeeper® surgery between May 2017 and August 2020. Patients who took part in our study had previous treatment for faecal incontinence by a variety of methods (both medical and surgical) and suffered from different types of FI (passive, urge, mixed, associated urinary incontinence). It was promising to see there was a clinically significant improvement in continence indicated by a decrease in Vaizey and Wexner scores (p=0.00377 and p=0.00334 respectively (Wilcoxon test)) with 11 patients improving in scores. It is reasonable to consider Sphinkeeper™ as a safe and minimally invasive surgical intervention to achieve some degree of positive improvement for patients suffering from faecal incontinence.

Sonographic postpartum anal sphincter defects and the association with pelvic floor pain and dyspareunia.

Pelvic floor pain and dyspareunia are both important entities of postpartum pelvic pain, often concomitant and associated with perineal tears during vaginal delivery. The association between postpartum sonographic anal sphincter defects, pelvic floor pain, and dyspareunia has not been fully established. We aimed to determine the prevalence of postpartum anal sphincter defects using three-dimensional endoanal ultrasonography (3D-EAUS) and evaluate their association with symptoms of pelvic floor pain and dyspareunia. This prospective cohort study followed 239 primiparas from birth to 12 months post delivery. Anal sphincters were assessed with 3D-EAUS 3 months postpartum, and self-reported pelvic floor function data were obtained using a web-based questionnaire distributed 1 year after delivery. Descriptive statistics were compared between the patients with and without sonographic defects, and the association between sonographic sphincter defects and outcomes were analyzed using logistic regression. At 3 months postpartum, 48/239 (20%) patients had anal sphincter defects on 3D-EAUS, of which 43 (18%) were not clinically diagnosed with obstetric anal sphincter injury at the time of delivery. Patients with sonographic defects had higher fetal weight than those without defects, and a perineum <2 cm before the suture was a risk factor for defects (odds ratio [OR], 6.9). Patients with sonographic defects had a higher frequency of dyspareunia (OR, 2.4), and pelvic floor pain (OR, 2.3) than those without defects. Our results suggest an association between postpartum sonographic anal sphincter defects, pelvic floor pain, and dyspareunia. A perineal height <2 cm, measured by bidigital palpation immediately postdelivery, was a risk factor for sonographic anal sphincter defect. We suggest offering pelvic floor sonography around 3 months postpartum to high- risk women to optimize diagnosis and treatment of perineal tears and include perineum <2 cm prior to primary repair as a proposed indication for postpartum follow-up sonography.

Evaluation of Anal Sphincter with High Resolution Anorectal Manometry and 3D Reconstruction in Patients with Anorectal Malformation

Background: Patients with anorectal malformation (ARM) need long-term follow-up, in order to evaluate fecal continence; the main predictors of longer-term success are the type of ARM, associated anomalies and sacral integrity. Three-Dimensional High Resolution Anorectal Manometry (3D-HRAM) gives detailed information on pressure on the anal complex profile. Our objective was to analyze anal sphincter activity in ARM patients with 3D-HRAM establishing the correlation between manometric and clinical data. Methods: Forty ARM patients were submitted to 3D-HRAM: manometric, anatomical and clinical scores were correlated with each other and with the bowel management response (BM). Results: A positive correlation between all scores and types of ARM was found: in high ARM and in patients with spinal anomalies (regardless to ARM type) lower scores were reported and even after BM they did not achieve good continence. Conclusions: 3D-HRAM gives detailed data on the functional activity of the anal sphincter complex. Our study revealed a correlation between manometric parameters and clinical outcomes, confirming spinal malformations and ARM type as the most important prognostic risk factors for a bad outcome. Specific sphincteric defects can also be explored with manometry, allowing for tailored bowel management strategies.

Correlation of anorectal symptoms and endoanal ultrasound findings after obstetric anal sphincter injuries (OASIS).

Obstetric anal sphincter injuries (OASIS) predispose to development of anorectal symptoms that affect women's quality of life. A retrospective cohort study was conducted for all women with singleton vaginal deliveries who had a primary OASIS repair and attended the Postpartum Perineal Clinic between July 1st 2017 and December 31st 2020. This study was approved by the Research Ethics Board. The purpose of this study was (1) to determine correlation between endoanal ultrasound (EAUS) findings and anorectal symptoms quantified by the St. Mark's Incontinence Score (SMIS), (2) to determine the incidence of residual anal sphincter defects, and (3) to determine the rate of clinical overdiagnosis of OASIS. Pearson correlation coefficient was used to assess correlation between anorectal symptoms and EAUS findings. A total of 247 participants with clinical diagnosis of OASIS met the inclusion criteria. A 3rd-degree tear was identified in 126 (51.0%) and 4th-degree tear was identified in 30 (12.1%) participants. In participants with sonographic evidence of OASIS, there was a statistically significant weak positive correlation between the size of residual defect and SMIS for both external anal sphincter (EAS) (r= .3723, p<.0001) and internal anal sphincter (IAS) (r= .3122, p=.0180). Residual defect in the anorectal sphincter of greater than 1 hour (>30°) in width was present in 64.3% participants with 3rd-degree tear and 86.7% participants with 4th-degree tear. The rate of overdiagnosis was 36.8%. The size of residual defect of EAS and IAS has a weak positive correlation with anorectal symptoms, emphasizing the importance of EAUS for counselling regarding mode of subsequent delivery.

Assessing Obstetric Anal Sphincter Injuries: A Comparison of Exoanal and Endoanal Ultrasound.

To explore the differences in assessing obstetric anal sphincter injuries (OASI) between transperineal ultrasound (TPUS) and endoanal ultrasound (EAUS) and test relationships between ultrasound findings and anal incontinence (AI) symptoms. A group of 196 women with a history of vaginal delivery was recruited. OASI was detected in a set of 5 slices by EAUS and 8 slices by TPUS. OASI grading was performed on TPUS rules and EAUS rules. A "significant sphincter defect" was diagnosed by TPUS and EAUS using "2/3 rules." Symptoms of AI were determined using the St Mark's Incontinence Score (SMIS). Ultrasound findings were compared between the two methods and correlated with symptoms. Of 196 women, 29 (14.8%) suffered from AI with a mean SMIS of 12.1 ± 4.5, and 70 (35.7%) women with a mean age of 57 years had suspected OASI on imaging. Twenty-one (10.7%) "significant defects" were diagnosed by TPUS and 24 (12.2%) by EAUS. OASI Grades on TPUS had good agreement with EAUS rules (k=0.70, P < .001). Logistic regression analysis showed that OASI Grade on imaging and "significant sphincter defects" seen on both forms of imaging were associated with AI symptoms. The odds ratio was 46 and 38 for "significant defects" on TPUS and EAUS, and 14 and 7 for OASI 3b+ on TPUS and EAUS in predicting AI, respectively. "Significant defects" diagnosed by EAUS or TPUS and OASI Grade 3b+ predict AI symptoms. The diagnostic performance of endoanal and exoanal ultrasound (EAUS and TPUS) appear to be very similar.