Current update on the role of endoanal ultrasound: a primer for radiologists.

Endoanal ultrasound (EAUS) is a valuable imaging modality for the evaluation of anal and perianal pathologies. It provides detailed information about the anatomy and physiology of the anorectal region and has been used in pre-and post-operative settings of anorectal pathologies. EAUS is not only useful in the evaluation of benign pathologies but also in loco-regional staging of anal and rectal tumors. EAUS has several advantages over MRI, including reduced cost, better patient tolerance, and improved scope of application in patients with contraindications to MRI. Despite its benefits, EAUS is not widely performed in many centers across the globe. This article aims to educate radiologists, trainees, and surgeons about the indications, contraindications, patient preparation, imaging technique, and findings of EAUS. We will also highlight the technical difficulties, diagnostic challenges, and procedural complications encountered during EAUS, along with a comparative analysis of EAUS with other imaging approaches.

Convolutional neural network deep learning model accurately detects rectal cancer in endoanal ultrasounds.

BACKGROUND: Imaging is vital for assessing rectal cancer, with endoanal ultrasound (EAUS) being highly accurate in large tertiary medical centers. However, EAUS accuracy drops outside such settings, possibly due to varied examiner experience and fewer examinations. This underscores the need for an AI-based system to enhance accuracy in non-specialized centers. This study aimed to develop and validate deep learning (DL) models to differentiate rectal cancer in standard EAUS images. METHODS: A transfer learning approach with fine-tuned DL architectures was employed, utilizing a dataset of 294 images. The performance of DL models was assessed through a tenfold cross-validation. RESULTS: The DL diagnostics model exhibited a sensitivity and accuracy of 0.78 each. In the identification phase, the automatic diagnostic platform achieved an area under the curve performance of 0.85 for diagnosing rectal cancer. CONCLUSIONS: This research demonstrates the potential of DL models in enhancing rectal cancer detection during EAUS, especially in settings with lower examiner experience. The achieved sensitivity and accuracy suggest the viability of incorporating AI support for improved diagnostic outcomes in non-specialized medical centers.

The Italian Unitary Society of Colon-proctology (SIUCP: Società Italiana Unitaria di Colonproctologia) guidelines for the management of anal fissure.

INTRODUCTION: The aim of these evidence-based guidelines is to present a consensus position from members of the Italian Unitary Society of Colon-Proctology (SIUCP: Società Italiana Unitaria di Colon-Proctologia) on the diagnosis and management of anal fissure, with the purpose to guide every physician in the choice of the best treatment option, according with the available literature. METHODS: A panel of experts was designed and charged by the Board of the SIUCP to develop key-questions on the main topics covering the management of anal fissure and to performe an accurate search on each topic in different databanks, in order to provide evidence-based answers to the questions and to summarize them in statements. All the clinical questions were discussed by the expert panel in different rounds through the Delphi approach and, for each statement, a consensus among the experts was reached. The questions were created according to the PICO criteria, and the statements developed adopting the GRADE methodology. CONCLUSIONS: In patients with acute anal fissure the medical therapy with dietary and behavioral norms is indicated. In the chronic phase of disease, the conservative treatment with topical 0.3% nifedipine plus 1.5% lidocaine or nitrates may represent the first-line therapy, eventually associated with ointments with film-forming, anti-inflammatory and healing properties such as Propionibacterium extract gel. In case of first-line treatment failure, the surgical strategy (internal sphincterotomy or fissurectomy with flap), may be guided by the clinical findings, eventually supported by endoanal ultrasound and anal manometry.

Preoperative Assessment of Perianal Fistulas with Combined Magnetic Resonance and Tridimensional Endoanal Ultrasound: A Prospective Study.

BACKGROUND: we designed a prospective study of diagnostic accuracy that compared pelvic MRI and 3D-EAUS with pelvic MRI alone in the preoperative evaluation and postoperative outcomes of patients with perianal fistulas. METHODS: the sample size was 72 patients and this was divided into two imaging groups. MRI alone was performed on the first group. Both MRI and 3D-EAUS were performed in parallel on the second group. Surgical exploration took place after two weeks and was the standard reference. Park's classification, the presence of a concomitant abscess or a secondary tract, and the location of the internal opening were recorded. All patients were re-evaluated for complete fistula healing and fecal incontinence six months postoperatively. All of the collected data were subjected to statistical analysis. RESULTS: the MRI group included 36 patients with 42 fistulas. The MRI + 3D-EAUS group included 36 patients with 46 fistulas. The adjusted sensitivity and negative predictive value were 1.00 for most fistula types in the group that underwent combined imaging. The adjusted specificity improved for intersphincteric fistulas in the same group. The adjusted balanced accuracy improved for all fistula types except rectovaginal. The combination of imaging methods showed improved diagnostic accuracy only in the detection of a secondary tract. The healing rate at six months was 100%. Fecal incontinence at six months did not present a statistically significant difference between the two groups (Fisher's exact test p-value > 0.9). Patients with complex perianal fistulas had a statistically significant higher probability of undergoing a second surgery (x2 test p-value = 0.019). CONCLUSIONS: the combination of pelvic MRI and 3D-EAUS showed improved metrics of diagnostic accuracy and should be used in the preoperative evaluation of all patients with perianal fistulas, especially those with complex types.

Impact of Preoperative Three-Dimensional Endoanal Ultrasound on the Surgical Outcome of Primary Fistula in Ano. A Multi-Center Observational Study of 253 Patients.

PURPOSE: To evaluate the impact of preoperative three-dimensional endoanal ultrasound (3D-EAUS) on the clinical outcome of anal fistula surgery. METHODS: The research consisted of multi-center retrospective case-control study including 253 consecutive adult patients undergoing surgery for confirmed or suspected primary fistula in ano who had undergone preoperative 3D-EAUS evaluation between January 2011 and January 2021. Main outcome measures were the concordance (K value) between ultrasound results and surgery in the identification of fistulas internal openings, primary tracts and secondary extensions and the 6 and 12 months success rate in patients with concordant and discordant findings. RESULTS: A good agreement in the identification of the main fistulas characteristics between ultrasound results and operative findings was found. A significant difference (P < .0001; Fisher's exact test) in the success rate was found between patients with concordant and discordant ultrasound results and operative findings in identification or location of internal opening. Particularly, all the 11 (4.8%) patients with discordant results experimented a failure of the surgical procedure at 6 months follow-up. At re-operation, the shift from discordant to concordant results was associated with an 81.8% 12 months success-rate. CONCLUSION: The three-dimensional endoanal ultrasound preoperative evaluation may have a relevant impact on the outcome of a defined group of patients undergoing surgery for anal fistula, since the careful evaluation of ultrasound results could simplify the internal orifice intra-operative detection and improve the success rate.

Clinical, ultrasonographic, and functional outcomes after obstetric anal sphincter injury primary repair: A single-center experience.

OBJECTIVE: To present clinical and instrumental sequelae after obstetric anal sphincter injuries (OASIS), evaluating correlations between intrapartum severity of lesions, postpartum symptoms, and sonographic and manometric findings; outcomes during subsequent deliveries were also evaluated. METHODS: This retrospective study evaluated all consecutive women who sustained an OASIS between 2015 and 2020. Postpartum symptoms, anorectal manometry (ARM), and three-dimensional endoanal ultrasonography (3D-EAUS) were analyzed. RESULTS: A total of 107 women underwent OASIS primary repair; 84 (78.5%) of them were asymptomatic after 1 month. The presence and severity of symptoms showed a great correlation with instrumental outcomes in terms of maximum resting pressure, squeeze pressure increment (SPI), circumferential extension of defect for both external anal sphincter (EAS) and internal anal sphincter (IAS), and EAS, IAS and total Starck scores. There was a significant correlation between ARM and 3D-EAUS findings, with the exception of SPI, for which the abnormalities were not predictable based on EAUS results. CONCLUSION: Both ARM and EAUS findings after OASIS are directly related to each other, and associated with symptoms. These instrumental tools may be useful for OASIS assessment and counseling.

Postoperative three-dimensional endoanal ultrasound findings and relation to anal fistula plug failure.

OBJECTIVES: To explore the utilization of three-dimensional (3D) endoanal ultrasound (EAUS) for the follow-up of the anal fistula plug (AFP), describe morphological findings in postoperative 3D EAUS, and evaluate if postoperative 3D EAUS combined with clinical symptoms can predict AFP failure. MATERIALS AND METHODS: A retrospective analysis of 3D EAUS examinations performed during a single-centre study of prospectively included consecutive patients treated with the AFP between May 2006 and October 2009. Postoperative assessment by clinical examination and 3D EAUS was performed at 2 weeks, 3 months and 6-12 months ("late control"). Long-term follow-up was carried out in 2017. The 3D EAUS examinations were blinded and analysed by two observers using a protocol with defined relevant findings for different follow-up time points. RESULTS: A total of 95 patients with a total of 151 AFP procedures were included. Long-term follow-up was completed in 90 (95%) patients. Inflammation at 3 months, gas in fistula and visible fistula at 3 months and at late control, were statistically significant 3D EAUS findings for AFP failure. The combination of gas in fistula and clinical finding of fluid discharge through the external fistula opening 3 months postoperatively was statistically significant (p < 0.001) for AFP failure with 91% sensitivity and 79% specificity. The positive predictive value was 91%, while the negative predictive value was 79%. CONCLUSIONS: 3D EAUS may be utilized for the follow-up of AFP treatment. Postoperative 3D EAUS at 3 months or later, especially if combined with clinical symptoms, can be used to predict long-term AFP failure.ClinicalTrials.gov identifier NCT03961984.

Comparison of MRI and Endoanal Ultrasound in Assessing Intersphincteric, Transsphincteric, and Suprasphincteric Perianal Fistula.

OBJECTIVES: Perianal fistula is a common disorder characterized by an anomalous perianal track connecting two epithelialized surfaces, most commonly the anal canal and the perianal skin. Although each has its limitations, magnetic resonance imaging (MRI) and endoanal ultrasound are currently two acceptable modalities for assessing perianal fistula. This study aimed to evaluate the accuracy of MRI and endoanal ultrasonography in diagosing perianal fistula, considering the surgical results as the references. METHODS: This prospective cohort study was performed on patients with symptomatic perianal fistulas. MRI results of patients reported by the radiologist were collected along with the findings of endoanal ultrasonography performed by a gastroenterologist. These results were compared with surgical findings as the reference standard. RESULTS: The study enrolled 126 patients. Exactly 222 definitive fistulas were identified during surgery. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ultrasound for perianal fistula were 87.38, 38.46, 92.38, 26.31, and 82.25% respectively; and for MRI were 76.12, 57.69, 93.88, 22.05, and 74.19% respectively. The accuracy of endoanal ultrasound for detecting transsphincteric and intersphincteric fistulas was higher than MRI. In contrast, the diagnostic value of MRI for detecting suprasphincteric fistulas was higher than endoanal ultrasound. CONCLUSIONS: Using endoanal ultrasonography to diagnose perianal fistulas is a relatively accurate method. This method may be more sensitive than MRI in detecting patients with perianal fistulas and abscesses.

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

INTRODUCTION: Obstetric anal sphincter injuries (OASIS) predispose to development of anorectal symptoms that affect women's quality of life. METHODS: 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. RESULTS: 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%. CONCLUSION: 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.

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: "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.

Combined 3D Endoanal Ultrasound and Transperineal Ultrasound Improves the Detection of Anal Sphincter Defects.

INTRODUCTION: Anal sphincter injury, mainly due to obstetric or iatrogenic etiology, is the most common cause of fecal incontinence (FI). Three-dimensional endoanal ultrasound (3D EAUS) is used for assessment of the integrity and the degree of anal muscle injury. However, 3D EAUS accuracy may be hampered by regional acoustic effects, such as intravaginal air. Therefore, our aim was to examine whether a combination of transperineal ultrasound (TPUS) and 3D EAUS would improve the accuracy of detection of anal sphincter injury. METHODS: We prospectively performed 3D EAUS followed by TPUS in every patient evaluated for FI in our clinic between January 2020 and January 2021. The diagnosis of anal muscle defects was assessed in each ultrasound technique by two experienced observers that were blinded to each other's assessments. Interobserver agreement for the results of the 3D EAUS and the TPUS exams was examined. A final diagnosis of anal sphincter defect was based on the results of both ultrasound methods. Discordant results were re-analyzed by the two ultrasonographers for a final consensus on the presence or absence of defects. RESULTS: A total of 108 patients underwent ultrasonographic assessment due to FI (mean age 69 ± 13). Interobserver agreement for the diagnosis of tear on EAUS and TPUS was high (83%) with Cohen's kappa of 0.62. EAUS confirmed anal muscle defects in 56 patients (52%), while TPUS confirmed them in 62 patients (57%). The final consensus agreed on the diagnosis of 63 (58%) muscular defects and 45 (42%) normal exams. The Cohen's kappa coefficient of agreement between the results of the 3D EAUS and the final consensus was 0.63. CONCLUSIONS: The combination of 3D EAUS and TPUS improved the detection of anal muscular defects. The application of both techniques for the assessment of the anal integrity should be considered in every patient going through ultrasonographic assessment for anal muscular injury.

Impact of sex and aging on radiographic and functional parameters of the anal sphincter complex in patients with accidental bowel leakage.

AIMS: Treatment outcomes for accidental bowel leakage (ABL) may be influenced by age-related sarcopenia. We sought to determine if thickness of the anal sphincter complex on endoanal ultrasound correlated with function in women and men with ABL and if women demonstrated age-related anal sphincter thinning. METHODS: Consecutive patients with ABL presenting to our pelvic floor clinic from 2012 to 2017 were included. Clinical data were obtained from medical records. External anal sphincter (EAS), imaged by endoanal ultrasound at proximal, mid and distal locations, and IAS thickness were measured at 12, 3, 6, and 9 o'clock; puborectalis muscle (PRM) was measured at 4, 6, and 8 o'clock; and averaged. Anorectal manometry was conducted when clinically indicated. Data were compared using Mann-Whitney tests and linear regression. Results are reported as mean ± SD or median (IQR). RESULTS: Women (n = 136) were younger than men (n = 26) (61 ± 13 vs. 67 ± 13 years, p = 0.02). More women than men had pelvic surgery and less had colorectal surgery, spinal disorders, or a history of smoking (p < 0.05). Eighty-two percentage of women had an anal sphincter defect versus 31% of men (p < 0.01). All anal sphincter complex components were thinner in women than men with lower squeeze and resting pressures (p < 0.03), even in nulliparous women. Mean resting pressure was lower in older 6.1 (4.6-7.8) versus younger women 8.3 (5.0-12.9) mmHg, p = 0.04. CONCLUSIONS: Women, even nulliparous, with ABL demonstrate thinner and weaker anal sphincters than men, Aging correlated with an increase in anal sphincter thickness, suggesting that age-related changes in the intrinsic components of the anal sphincter complex associated with ABL are complex and are not always well demonstrated on endoanal ultrasound.

Underdiagnosis of internal anal sphincter trauma following vaginal delivery.

OBJECTIVE: Damage to the anal sphincter during childbirth remains the leading cause of fecal incontinence in women. Defects in the internal (IAS) or external anal sphincter, alongside symptoms and sphincter tone, will generally dictate the suggested mode of delivery in any successive pregnancy. This study aimed to examine using endoanal ultrasonography the prevalence of IAS damage in women referred with Grade-3a or -3b obstetric anal sphincter injury (OASI) in a tertiary-referral perineal clinic. METHODS: This was a retrospective observational study of all women referred to a tertiary-referral perineal clinic after primary repair of OASI (Grade 3a-c, 4) diagnosed for the first time following vaginal delivery between January 2016 and December 2019, inclusive. Women were assessed using the Wexner bowel continence questionnaire, digital examination of sphincter tone and endoanal ultrasound. Injuries in each sphincter were classified as a scar (≤ 30°) or defect (> 30-90° or > 90°) on endoanal imaging in the axial plane. RESULTS: In total, 615 women were referred following primary repair of OASI. Sonographic evidence of damage to the IAS was seen in 9.1% (46/506) of women diagnosed with a Grade-3a/3b injury. In women referred with a Grade-3a/3b tear, symptom scores were statistically higher (P = 0.025) in those with an IAS defect > 30° compared to those with an intact or scarred IAS, although the median score was zero in both groups. The proportion of women in each group with severe symptoms (score > 9) was similar (2.6% vs 6.5%; P = 0.148). Among women referred with a Grade-3a/3b tear, sphincter tone was reduced more frequently in those with a defect of the IAS than in those with an intact or scarred IAS (52.2% vs 11.7%; odds ratio, 8.14 (95% CI, 4.26-15.67); P < 0.001). Regardless of the reason for referral, women with reduced sphincter tone on rectal examination were four times as likely to have had an IAS defect > 30° than were those with normal resting tone (risk ratio, 4.58 (95% CI, 3.25-6.45); P < 0.001). CONCLUSIONS: One in 11 women diagnosed with a Grade-3a or -3b tear have evidence of damage to their IAS on endoanal ultrasound. Damage to this muscle is linked to fecal incontinence in women and can have a significant impact on the planning of any future deliveries. This study highlights the importance of established perineal clinics with access to ultrasound. Nonetheless, if reduced sphincter tone is felt on rectal examination, a clinician should have a high index of suspicion for an occult IAS injury. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Use of endoanal ultrasound in detecting obstetric anal sphincter injury immediately after birth.

INTRODUCTION: Obstetric anal sphincter injury (OASI) complicates around 5% of deliveries in primiparas. The study objective was to assess the utility of three-dimensional endoanal ultrasonography (3D-EAUS) in the diagnosis of OASI. MATERIAL AND METHODS: The present study was designed to mirror screening settings with an unselected cohort of nulliparous women. All enrolled patients underwent clinical examination of the perineum by the caregiver, and 3D-EAUS was conducted. Post-processing of ultrasonography volume data was performed by an experienced colorectal surgeon who was blinded to all other data. The sensitivity, specificity, negative predictive value, and positive predictive value of 3D-EAUS in the diagnosis of OASI was evaluated. The trial is registered at ISCRTN: 18006769. RESULTS: A total of 680 scans were performed, of which 18.5% were judged as "non-assessable", resulting in 554 assessable recordings. Sphincter defects were observed in 12.8% of all assessable recordings on 3D-EAUS (n = 71). With clinical examination set as the reference standard, ultrasound sensitivity in the diagnosis of OASI was 30.4%, whereas its specificity was 87.9%. The negative predictive value was 96.7% and the positive predictive value was only 9.9%. Comments were left on 175 examinations, of which 74% referred to the management of the examination. CONCLUSIONS: Using 3D-EAUS in a maternity ward is demanding because staff generally have little experience in endoanal ultrasound, which contributes to difficulties in obtaining good image quality. When 3D-EAUS is performed to mirror screening settings, it adds no convincing diagnostic power to clinical examination in the diagnosis of OASI.

Diagnostic capabilities of transperineal ultrasound (TPUS) to evaluate anal sphincter defect post obstetric anal sphincter injury (OASIS)? A systematic review.

INTRODUCTION: Endoanal ultrasound (3D-EAUS) is the gold standard imaging investigation for evaluating the anal sphincter; unfortunately, it is not universally available in most obstetric units. This study aims to appraise the ability of transperineal ultrasound (TPUS) compared with 3D-EAUS as the gold standard to identify anal sphincter defects after primary repair of OASIS. METHODS: A systematic search of major databases to identify diagnostic accuracy of 3D-TPUS in evaluating anal sphincter defects. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were designed for this systematic review. The risk of bias and applicability concerns were assessed using the QUADAS-2 tool. Our eligibility criteria are patients with a history of primary repair of anal sphincter injuries (OASIS). They were followed up after the primary repair to detect the anal sphincter defect using 3D-TPUS vs. 3D-EAUS as a gold standard. RESULTS: Two eligible observational studies were included and assessed for risk of bias using the QUADAS-2 tool and showed a low risk of bias and a low risk of concerns. 3D-TPUS had various sensitivity to detect external anal sphincter defects in two studies; meanwhile, the specificity was around 67-70%. For detecting the internal anal sphincter defects, 3D-TPUS had low sensitivity but high specificity (93-94%). CONCLUSION: 3D-TPUS had various sensitivity to detect external anal sphincter defects and low sensitivity to detect internal anal sphincter defects. On the other hand, 3D-TPUS had low specificity for detecting external anal sphincter defects and high specificity for detecting internal anal sphincter defects.

Postpartum perineal wound infection and its effect on anal sphincter integrity: Results of a prospective observational study.

INTRODUCTION: Perineal wound infection can affect tissues at superficial, deep, and organ space levels. Women with obstetric anal sphincter injuries (OASIS) are at risk of infection; however, no study to date has investigated if infection can extend to affect the anal sphincter integrity. The aim of this study was to evaluate the clinical progression of perineal wound infection and its effect on the anal sphincter in women with or without OASIS using three-dimensional endoanal ultrasound (3D-EAUS). MATERIAL AND METHODS: Women were recruited into the Prospective Observational Study Evaluating the Sonographic Appearance of the Anal Sphincter in Women With Perineal Wound Infection Following Vaginal Delivery (PERINEAL Study) between August 2020 and August 2021 (NCT04480684). 3D-EAUS was performed weekly until complete wound healing. Significant bacterial colonization was diagnosed using the MolecuLight i:X camera. The primary study outcome was a change in a sphincter defect angle from baseline (wound infection) until wound healing. A robust Poisson regression model was used to analyze the effect of significant bacterial loads on the anal sphincter. RESULTS: Seventy-three women were included. A median of two ultrasound scans were performed in each patient (range 1-16). Five women (6.8%) had an OASI clinically diagnosed at delivery. In total, 250 EAUS were performed. An external anal sphincter defect was found on EAUS in 55 (22.0%) scans (n = 10 women). An external anal sphincter and internal anal sphincter defect was found in 26 scans (10.4%) (n = 3 women). During the course of the wound healing process, there was no significant change in defect size in wounds with or without significant bacterial colonization. In cases of an intact anal sphincter, wound infection did not disrupt its integrity. CONCLUSIONS: We found that perineal wound infection does not disrupt an intact anal sphincter or OASIS. This new information can provide important information for clinicians and patients. As there are myths frequently encountered in cases of litigation when disruption of sphincter integrity is attributed to perineal infection, the findings of this study should be tested in larger studies in the future.

Efficacy and Safety of Endoanal Ultrasound-Guided Botulinum Toxin in Chronic Anal Fissure.

We aimed to evaluate the efficacy and safety of endoanal ultrasound (EAUS)-guided botulinum toxin (BT) in the treatment of chronic anal fissure (CAF). All patients were classified into 2 groups: conventional and EAUS groups. In total, 90 units of BT were injected into the internal anal sphincter at the 3, 6, and 9 o'clock positions in the EAUS group. An injection was performed into the intersphincteric space at the 3, 6, and 9 o'clock positions in the conventional group. Adverse effects and efficacy were analyzed. There were 44 patients: 26 in the conventional group and 18 in the EAUS group. Pain and incontinence rates were similar between groups (P > .05). The efficacy rate was higher in the EAUS group (69.23%) than in the conventional group (81.82%), but this difference was not significant (P = .466). EAUS-guided BT injection is safe and effective in patients with CAFs.

3T external phased-array magnetic resonance imaging in detection of obstetric anal sphincter lesions: a pilot study.

BACKGROUND: Three-dimensional endoanal ultrasound (3D EAUS) has been the gold standard for detecting anal sphincter lesions in patients with a history of obstetric anal sphincter injury (OASI). Advances in imaging technologies have facilitated the detection of these lesions with external phased-array magnetic resonance imaging (MRI), which could offer an alternative imaging modality for the diagnosis of residual OASI (ROASI) in centers where 3D EAUS imaging is not available. PURPOSE: To compare two diagnostic modalities: the 3D EAUS and 3T external phased-array MRI in the detection of residual anal sphincter lesions. MATERIAL AND METHODS: A total of 24 women with a history of OASI were imaged with both 3D EAUS and 3T external phased-array MRI after primary repair of the injury. Intraclass correlation (ICC) and interrater reliability (IRR) values were calculated for the grade and circumference of the sphincter lesion. Sphincter lesions were graded according to the Sultan classification. RESULTS: There was an almost perfect agreement between 3D EAUS and 3T external phased-array MRI in determining the extent of the sphincter lesions according to the Sultan classification (κ = 0.881; P < 0.001) and the circumference of the external anal sphincter defects, measured in degrees (κ = 0.896; P < 0.001). CONCLUSION: The results of this study indicate that 3T external phased-array MRI and 3D EAUS yield comparable results in the diagnosis of ROASI. These findings suggest that 3T external phased-array MRI could serve as an alternative diagnostic modality to 3D EAUS in the diagnosis of ROASI.

The role of anal manometry in the follow-up of women with obstetric anal sphincter injuries (OASI).

INTRODUCTION AND HYPOTHESIS: Mode of birth (MOB) following OASI is determined by choice, symptoms and anorectal study results in asymptomatic women. Endoanal ultrasound (EAUS) is the gold-standard imaging modality. EAUS use in MOB counselling is supported by strong evidence. Less is understood about how anal manometry (AM) influences MOB counselling. METHODS: A retrospective observational study was conducted from 2007 to 2020. Women underwent symptom assessment using validated ePAQ and St Mark's incontinence score (SMIS). Anorectal studies using EAUS and AM were performed. The case group was the normal ultrasound group and the control group was the abnormal ultrasound group. Both groups were compared with normal and abnormal AM result groups. RESULTS: A total of 1348 women were included over 13 years. Among these, 454 women were symptomatic, 894 were asymptomatic; 274 (31%) asymptomatic women had isolated abnormal AM results, 313 (35%) had two abnormal anorectal results and 221 (24.7%) had normal anorectal results. Eighty-six asymptomatic women (10.4%) had isolated abnormal EAUS results, 138 (30.4%) symptomatic women had isolated abnormal AM, 221 (48.7%) had two abnormal anorectal results and 57 (12.6%) had normal anorectal results. Thirty-eight symptomatic women (8.4%) had an isolated abnormal EAUS result. CONCLUSIONS: AM identifies more women with sphincter function impairment than EAUS alone. Without AM, almost one third of asymptomatic women would not have been identified and could have been inadequately counselled. Performing AM and EAUS together captured most women with compromised anal sphincter function. We conclude that AM should be performed in all women with OASI alongside EAUS to enable accurate MOB counselling.

Incidence and risk factors for secondary failure after acute obstetric sphincter injury repair - an audit of 239 women.

AIM: The rate of secondary failure after obstetric sphincter injury repair is unknown, with the literature reporting rates ranging from 0.1% to 53%. We aimed to perform an audit to identify the rate and risk factors for failure of sphincter repair in a cohort of postpartum women using endoanal ultrasound (EAUS) and manometry, assessing the risk factors and impact of these events. METHOD: Prospective data were collected within a 2 year period from patients who attended the perineal clinic at Eastern Health. Variables of primary repair and presence of postpartum complications were recorded and subsequently analysed. RESULTS: Of 239 patients with obstetric anal sphincter injury (OASI) included, 100 (41.8%) had EUAS evidence of sphincter defects. Only 20% with secondary repair failure were symptomatic with faecal or flatal incontinence at a mean follow-up of 23.4 months postpartum. Patients with secondary repair failure had lower anal resting (p = 0.006) and maximum squeeze pressures compared with patients with intact repairs (p < 0.001). In terms of variables that were investigated, namely location, operator hierarchy, type of repair and material used, none had a statistically significant correlation with secondary repair failure of OASI. Postpartum complications had an overall incidence of 12.7%, and those with any complication were found to have an increased rate of secondary failure of repair (p = 0.157). CONCLUSION: Using EAUS to confirm secondary failure of repair, incidence was 41.4% in this cohort. There were no identifiable modifiable variables that reduced the risk of secondary failure of repair. Further prospective research with increased sample size and longer follow-up periods is required to assess the validity of the findings.