Intersphincteric resection following robotic-assisted versus laparoscopy-assisted total mesorectal excision for middle and low rectal cancer: a multicentre propensity score analysis of 1571 patients.

BACKGROUND: Robotic-assisted total mesorectal excision (RaTME) may be associated with reduced conversion to an open approach and a higher rate of complete total mesorectal excision (TME); however, studies on its advantages in intersphincteric resection (ISR) are inadequate. MATERIALS AND METHODS: This retrospective multicenter cohort study enroled consecutive patients who underwent RaTME and laparoscopy-assisted total mesorectal excision (LaTME) at four medical centres between January 2020 and March 2023. Propensity score matching (PSM), inverse probability of treatment weight (IPTW), and multivariate logistic regression analyses were performed. The primary outcome was the ISR rate. Secondary outcomes were coloanal anastomosis (CAA), conversion to open surgery, conversion to transanal TME, abdominoperineal resection, postoperative morbidity and mortality within 30 days, and pathological outcomes. RESULTS: Among the 1571 patients, 1211 and 450 underwent LaTME and RaTME, respectively, with corresponding ISR incidences of 5.3% and 8.4% ( P =0.024). After PSM and IPTW, RaTME remained associated with higher ISR rates (4.5% versus 9.4%, P =0.022 after PSM; 4.9% versus 9.2, P =0.005 after IPTW). This association remained in multivariate analysis after adjusting for other confounding factors. RaTME was further associated with a higher CAA rate, longer operating time, and higher hospitalization expenses. CONCLUSIONS: RaTME may facilitate ISR in middle and low rectal cancers, showing an independent association with a higher ISR incidence, with pathological outcomes and complications comparable to those of LaTME. However, it may also require a longer operating time and incur higher hospitalization expenses.

Comparing three-dimensional endorectal ultrasound and magnification chromoendoscopy for early rectal neoplasia invasion depth assessment.

INTRODUCTION: Accurate assessment of invasion depth of early rectal neoplasms is essential for optimal therapy. We aimed to compare three-dimensional endorectal ultrasound (3D-ERUS) with magnification chromoendoscopy (MCE) regarding their accuracy in assessing parietal invasion depth (T). METHODS: Patients with middle and distal rectum neoplasms were prospectively included. Two providers blinded to each other's assessment performed 3D-ERUS and MCE, respectively. The T stage assessed through ERUS was compared to the MCE evaluation. The results were compared to the surgical specimen anatomopathological report. Sensitivity, specificity, accuracy, positive (PPV), and negative (NPV) predictive values were calculated for the T stage and for the final therapy (local excision or radical surgery). RESULTS: In 8 years, 70 patients were enrolled, and all underwent both exams. MCE and ERUS showed an accuracy of 94.3% and 85.7%, sensitivity of 83.7 and 93.3%, specificity of 96.4 and 83.6%, PPV of 86.7 and 60.9%, and NPV of 96.4 and 97.9%, respectively. Kappa for T stage assessed through ERUS was 0.64 and 0.83 for MCE. CONCLUSION: MCE and 3D-ERUS had good diagnostic performance, but the endoscopic method had higher accuracy. Both methods reliably assessed lesion extension, circumferential involvement, and distance from the anal verge.

Cancer of colon, rectum and anus: the rising burden of disease worldwide from 1990 to 2019.

BACKGROUND: Previous studies suggest that trends of cancer of colon, rectum and anus (CRA) incidence and mortality have been decreasing in recent decades. However, the trends are not uniform across age groups. This study aimed to assess the trends of the cancer of CRA burden worldwide. METHODS: A descriptive study was carried out with a joinpoint regression analysis using the database of the Global Burden of Disease study. RESULTS: About 2.2 million new cases of cancer of CRA were diagnosed in the world in 2019, whereby cancer of CRA caused ~1.1 million deaths. Globally, the incidence trend in both sexes together was increasing in 1990-2019, while the mortality trend was decreasing. The highest rise both in incidence and mortality was observed in the East Asia region (by 3.6% per year and by 1.4% per year, respectively) and the Andean Latin America region (by 2.7% per year and by 1.2% per year, respectively). However, of particular concern is the significant increase in the incidence (by 1.7% per year) and mortality (by 0.5% per year) from cancer of CRA in people aged 15-49. CONCLUSIONS: Unfavorable trends in cancer of CRA in the young require more attention in management plans.

Clinical utility of trans-sacral magnetic stimulation-evoked sphincter potentials and high-density electromyography in pelvic floor assessment: Technical evaluation.

AIM: Faecal incontinence is common and of multifactorial aetiologies, yet current diagnostic tools are unable to assess nerve and sphincter function objectively. We developed an anorectal high-density electromyography (HD-EMG) probe to evaluate motor-evoked potentials induced via trans-sacral magnetic stimulation (TSMS). METHOD: Anorectal probes with an 8 × 8 array of electrodes spaced 1 cm apart were developed for recording HD-EMG of the external anal sphincter. These HD-EMG probes were used to map MEP amplitudes and latencies evoked via TSMS delivered through the Magstim Rapid2 (MagStim Company). Patients undergoing pelvic floor investigations were recruited for this IDEAL Stage 2a pilot study. RESULTS: Eight participants (median age 49 years; five female) were recruited. Methodological viability, safety and diagnostic workflow were established. The test was well tolerated with median discomfort scores ≤2.5/10, median pain scores ≤1/10 and no adverse events. Higher Faecal Incontinence Severity Index scores correlated with longer MEP latencies (r = 0.58, p < 0.001) and lower MEP amplitudes (r = -0.32, p = 0.046), as did St. Mark's Incontinence Scores with both MEP latencies (r = 0.49, p = 0.001) and MEP amplitudes (r = -0.47, p = 0.002). CONCLUSION: This HD-EMG probe in conjunction with TSMS presents a novel diagnostic tool for anorectal function assessment. Spatiotemporal assessment of magnetically stimulated MEPs correlated well with symptoms and offers a feasible, safe and patient-tolerable method of evaluating pudendal nerve and external anal sphincter function. Further clinical development and evaluation of these techniques is justified.

Asian-white disparities in obstetric anal sphincter injury: Protocol for a systematic review and meta-analysis.

BACKGROUND: Obstetric anal sphincter injury (OASI) describes severe injury to the perineum and perineum and perianal muscles following birth and occurs in 4.4% to 6.0% of vaginal births in Canada. Studies from high-income countries have identified an increased risk of OASI in individuals who identify as Asian race versus those who identify as white. This protocol outlines a systematic review and meta-analysis which aims to determine the incidence of OASI in individuals living in high-income countries who identify as Asian versus those of white race/ethnicity. We hypothesize that the pooled incidence of OASI will be higher in Asian versus white birthing individuals. METHODS: We will search MEDLINE, OVID, Embase, Emcare and Cochrane databases from inception to 2022 for observational studies using keywords and controlled vocabulary terms related to race, ethnicity and OASI. Two reviewers will follow the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and Meta-analysis of Observational Studies (MOOSE) recommendations. Meta-analysis will be performed using RevMan for dichotomous data using the random effects model and the odds ratio (OR) as effect measure with a 95% confidence interval (CI). Subgroup analysis will be performed based on Asian subgroups (e.g., South Asian, Filipino, Chinese, Japanese individuals). Study quality assessment will be performed using The Joanna Briggs Institute Critical Appraisal tools. DISCUSSION: The systematic review and meta-analysis that this protocol outlines will synthesize the extant literature to better estimate the rates of OASI in Asian and white populations in non-Asian, high-income settings and the relative risk of OASI between these two groups. This systematic summary of the evidence will inform the discrepancy in health outcomes experienced by Asian and white birthing individuals. If these findings suggest a disproportionate burden among Asians, they will be used to advocate for future studies to explore the causal mechanisms underlying this relationship, such as differential care provision, barriers to accessing care, and social and institutional racism. Ultimately, the findings of this review can be used to frame obstetric care guidelines and inform healthcare practices to ensure care that is equitable and accessible to diverse populations.

[Advances in functional assessment and bowel rehabilitation following intersphincteric resection for low rectal cancer].

Intersphincteric resection (ISR) has been performed as an ultimate sphincter-sparing strategy in selected patients with low rectal cancer. Accumulating evidence suggests that ISR may be an interesting alternative to abdominoperineal resection to avoid a permanent stoma without compromising oncological outcomes. However, bowel dysfunction is a most common consequence of ISR not to be neglected. To date, limited clinical research has reported functional and quality of life outcomes according to patient-reported outcome measures. Also, data concerning management of low anterior resection syndrome are scarce due to lack of quality evidence. Therefore, this review provides an up-to-date summary of systematic assessment (including function, quality of life, manometry and morphology) and bowel rehabilitation for ISR patients. Postoperative anal function is often assessed by a combination of scales, including the Incontinence Assessment Scale, the Gastrointestinal Function Questionnaire, the Specific LARS Assessment Scale and the Faecal Diary. The condition-specific Quality of Life Scale is more appropriate for Quality-of-life measures in fecal incontinence after ISR. Patients' physiological function after ISR can be assessed using water- or high-resolution solid-state anorectal manometry. Anatomical and morphological changes can be assessed using defecography and 3D endorectal ultrasound. Electrical stimulation and biofeedback, pelvic floor exercises, rectal balloon training, transanal irrigation and sacral neuromodulation are all options for post-operative rehabilitation.

Three-dimensional pelvic ultrasound is a practical tool for the assessment of anal fistula.

OBJECTIVE: This study aims to investigate the diagnostic value of three-dimensional pelvic ultrasound in the preoperative assessment of anal fistula compared with findings of MRI and surgery. METHODS: A total of 67 patients (62 males) with suspected anal fistula were analyzed retrospectively. Preoperative three-dimensional pelvic ultrasound and magnetic resonance imaging were performed in all patients. The number of internal openings and the type of fistula were recorded. The accuracy of three-dimensional pelvic ultrasound was determined by comparing these parameters with surgical outcomes. RESULTS: At surgery, 5 (6%) were extrasphincteric, 10 (12%) were suprasphincteric, 11 (14%) were intersphincteric, and 55 (68%) were transsphincteric. There was no significant difference in the accuracy of pelvic 3D US and MRI, based on internal openings (97.92%, 94.79%), anal fistulas (97.01%, 94.03%), and those under Parks classification (97.53%, 93.83%). CONCLUSION: Three-dimensional pelvic ultrasound is a reproducible and accurate method for determining the type of fistula and detecting internal openings and anal fistulas.

Surgical Simulation of Posterior Sagittal Anorectoplasty for Rectovestibular Fistula: Low-Cost High-Fidelity Animal-Tissue Model.

PURPOSE: To provide a high-fidelity, animal tissue-based model for the advanced surgical simulation of a Posterior Sagittal Anorectoplasty (PSARP) for rectovestibular fistula in anorectal malformation (ARM). MATERIALS AND METHODS: A chicken cadaver was used to assess the feasibility of simulating a PSARP for rectovestibular fistula in ARM. No modification was required to implement the surgical simulation. RESULTS: A detailed description of the high-fidelity surgical simulation model is provided. The PSARP can be simulated while providing realistic anatomy (e.g. common wall between rectovestibular fistula and vagina), adequate rectal size, location and placement of the rectovestibular fistula, and proximity to the vagina. Haptic conditions of the tissue resemble human tissue and operative conditions as well. DISCUSSION: Concerning the decreased exposure of index cases of pediatric surgical trainees and pediatric surgeons in practice, simulation-based training can provide means to acquire or maintain the necessary skills to perform complex surgical procedures [1-5] Surgical simulation models for ARM are limited. Few low-cost trainers are available with predominant artificial and mostly unrealistic tissue [6-8] Animal models have the advantage of realistic multilayer tissue haptic feedback [6]. CONCLUSION: We provide a low-cost, high-fidelity model for correcting a rectovestibular fistula in a child with ARM, a complex operative procedure with low incidence but high-stake outcomes. The described tissue model utilizing the chicken cloaca anatomy provides a high-fidelity model for operative correction of rectovestibular ARM. For simulation purposes in the treatment of ARM, this model appears to be promising in terms of providing realistic pathology and haptic feedback in pediatric dimensions. LEVEL OF EVIDENCE: V.

Universal Urogynecologic Consultation and Screening for Fecal Incontinence in Pregnant Women With a History of Obstetric Anal Sphincter Injury: A Cost-Effectiveness Analysis.

IMPORTANCE: Obstetric anal sphincter injuries (OASIS) predispose for the development of fecal incontinence (FI), but management of subsequent pregnancy after OASIS is controversial. OBJECTIVE: We aimed to determine if universal urogynecologic consultation (UUC) for pregnant women with prior OASIS is cost-effective. STUDY DESIGN: We performed a cost-effectiveness analysis of pregnant women with a history of OASIS modeling UUC compared with no referral (usual care). We modeled the route of delivery, peripartum complications, and subsequent treatment options for FI. Probabilities and utilities were obtained from published literature. Costs using a third-party payer perspective were gathered from the Medicare physician fee schedule reimbursement data or published literature converted to 2019 U.S. dollars. Cost-effectiveness was determined using incremental cost-effectiveness ratios). RESULTS: Our model demonstrated that UUC for pregnant patients with prior OASIS was cost-effective. Compared with usual care, the incremental cost-effectiveness ratio for this strategy was $19,858.32 per quality-adjusted life-year, below the willingness to pay a threshold of $50,000/quality-adjusted life-year. Universal urogynecologic consultation reduced the ultimate rate of FI from 25.33% to 22.67% and reduced patients living with untreated FI from 17.36% to 1.49%. Universal urogynecologic consultation increased the use of physical therapy by 14.14%, whereas rates of sacral neuromodulation and sphincteroplasty increased by only 2.48% and 0.58%, respectively. Universal urogynecologic consultation reduced the rate of vaginal delivery from 97.26% to 72.42%, which in turn led to a 1.15% increase in peripartum maternal complications. CONCLUSIONS: Universal urogynecologic consultation in women with a history of OASIS is a cost-effective strategy that decreases the overall incidence of FI, increases treatment utilization for FI, and only marginally increases the risk of maternal morbidity.

Improved assessment of fecal incontinence in women with previous obstetric injury combining Low Anterior Resection Syndrome and Wexner scores.

OBJECTIVE: The aim of the current study was to assess whether Low Anterior Resection Syndrome (LARS) score could provide additional unique information to the Wexner score when assessing fecal incontinence (FI) in women with previous obstetric injury, thus providing a better foundation for treatment decisions. METHODS: This was a retrospective cohort study with intraindividual comparison of two scoring systems. Women with previous obstetric injury and diagnosed with FI between January 1, 2015, and December 31, 2018, with valid LARS and Wexner scores were included. Statistical methods used were Spearman rank correlation, Kendall τ, scatterplot, and ratios. RESULTS: Seventy women were included. Correlation coefficients varied from 0.42 to 0.66 (Spearman rank correlation) and 0.44 to 0.51 (Kendall τ). Cohen κ values varied from 0.33 to 0.67. No strong association was seen in the correlation analyses or the scatterplot. CONCLUSION: LARS score was shown to provide extra relevant information when assessing FI in women with previous obstetric injury. All symptoms should be considered relevant when assessing FI since it is a complex condition and should be approached accordingly. The authors suggest a combination of LARS and Wexner scores when assessing FI among women with previous obstetric injury.

In vivo assessment of the elastic properties of the external anal sphincter in term pregnant women using shear wave elastography.

INTRODUCTION AND HYPOTHESIS: The objective was to assess the intraobserver intersession and interobserver intrasession reliability of shear wave elastography applied to the external anal sphincter in term pregnant women. METHODS: This prospective study involved nulliparous pregnant women at 37 weeks or more with two visits (V1: one observer; V2 two observers) planned within a 12-h to 7-day interval. Measurements were performed using an Aixplorer V12® device with an SL 18-5 linear probe using a transperineal approach, allowing a measurement of the shear modulus (SM) in kPa. Measures were performed at rest, Valsalva maneuver, and maximal contraction. Reliability was assessed using the intraclass correlation coefficient (ICC). The study was approved by an ethics committee (ID RCB: 2020-A00764-65). RESULTS: A total of 37 women were included. Intraobserver reliability was excellent at rest (ICC = 0.91 [0.84-0.95) and good during the Valsalva maneuver (ICC = 0.83 [0.72-0.90]) and contraction (ICC = 0.85 [0.75-0.91]). Interobserver reliability was good at rest (ICC = 0.79 [0.66-0.87]) and during Valsalva (ICC = 0.84 [0.73-0.90]), but moderate during contraction (ICC = 0.70 [0.53-0.82]). CONCLUSIONS: Shear wave elastography is a reliable tool for assessing the elastic properties of the external anal sphincter in term pregnant women.

Assessment of Perineal Scars on Translabial Pelvic Floor Ultrasound: A Pilot Study.

OBJECTIVE: We aimed to describe a method for identifying and evaluating perineal scars using translabial pelvic floor ultrasound. We hypothesized that translabial ultrasound can identify a perineal scar and can differentiate episiotomies from spontaneous tears. METHODS: This pilot study is a secondary analysis of data obtained in the Epi-No® trial. Perineal integrity was assessed using volumes acquired on pelvic floor muscle contraction according to the method previously described for anal sphincter imaging. A scar was diagnosed if a hypoechoic distortion in the perineum was noted. We postulated that an episiotomy would result in a linear scar visible on four dimensional translabial ultrasound whereas nonlinear scars were considered the result of spontaneous perineal tear of grade 2 or higher. The results of this assessment were compared with data retrieved from electronic medical records. RESULTS: A scar was identified in 79/120 women (66%): 42 (35%) linear and 37 (31%) nonlinear. Sonographic and clinical diagnosis agreed on the presence or absence of perineal trauma in 66%. Agreement for the type of laceration was 50%. CONCLUSION: In this retrospective pilot study, a blinded assessment of translabial ultrasound volume data showed agreement between clinical data and sonographic assessment of perineal integrity in 66% and of type of laceration in 50%. More work is needed to optimize the method in assessment of perineal scars to improve its performance before it can be used in clinical audit and research.

Does Adding a Fissurectomy to Botox Sphincterotomy Increase Success Rate or Just Cost?

BACKGROUND: While Botox sphincterotomy with or without fissurectomy has been proven effective in healing anal fissures, they have not been directly compared. We evaluated cost-effectiveness and outcomes between Botox sphincterotomies with and without fissurectomy. METHODS: A 5-year retrospective review was conducted comparing all patients undergoing Botox sphincterotomy for anal fissure with or without fissurectomy. Outcomes including recurrence/persistence, additional treatments, complications, and total charges were compared between study groups. RESULTS: Patients treated without fissurectomy (n = 53) had recurrent/persistent fissure more often (56.6 vs 31.0%, P = .001), and required more Botox treatments. Those treated with fissurectomy (n = 154) had more complications (13.5 vs 0%, P = .003). Patients initially treated without fissurectomy had a median total charge of $2 973, while median total charge for those initially treated with fissurectomy was $17 925 (P < .001). CONCLUSIONS: Botox sphincterotomy in an office without fissurectomy is a viable option. It may result in longer healing times but is associated with reduced cost, lower complication rates, and no need for anesthesia or operative intervention in most cases. But the choice of treatment route must be individualized.

Cost-effectiveness comparison of delayed versus immediate coloanal anastomosis following ultralow anterior resection for rectal cancer.

BACKGROUND: Following ultralow anterior resection for distal rectal cancers, a coloanal anastomosis is usually created along with a defunctioning ileostomy (DI). Recent evidence suggests that abdominoperineal pull-through with delayed coloanal anastomosis (DCAA) is a viable alternative to immediate coloanal anastomosis (ICAA), minimizing the risk of anastomotic leakage and avoiding the need for stoma creation with the risk of stoma-associated morbidity. However, DCAA requires a longer initial hospitalization. We aimed to perform a cost-effectiveness analysis to compare DCAA versus ICAA for elective rectal cancer surgery. METHODS: A decision tree model was used to compare the cost-effectiveness of the two strategies. Cost data were obtained from the 2019 to 2020 United Kingdom National Health Service reference costs. Model probabilities were derived from published studies. Univariate and probabilistic sensitivity analyses were used to evaluate the robustness of the results. RESULTS: DCAA was the overall cheaper strategy at £13 541 compared with £14 856 for ICAA in the base case analysis. This was explained by the decreased overall costs of hospitalization/surgery, reduction in costs associated with anastomotic or stoma-related complications, specifically dehydration-induced hospital readmissions and avoidance of stoma maintenance costs. Sensitivity analysis demonstrated that DCAA remained consistently more inexpensive except when the duration of total parenteral nutrition exceeded 14 days. CONCLUSION: Despite a longer index hospitalization with higher initial costs, this economic analysis demonstrates that DCAA without stoma is overall more cost-effective compared with ICAA with DI following ultralow anterior resection. Cost savings should be considered an additional benefit when selecting the DCAA approach for rectal cancer surgery.

Self-assessment of nursing preparedness and knowledge in the care of patients with obstetric anal sphincter injuries and utilization of a computer-based learning module for continued nursing education in the United States.

IMPORTANCE: Perineal injury is the most common complication of vaginal delivery, and labor and delivery (L&D) nurses are crucial in managing and educating women following perineal trauma. OBJECTIVE: The aims of this study were to assess L&D nurse experience, knowledge, and self-perception of preparedness in caring for women with obstetric anal sphincter injuries (OASIS) and to compare pre- and post-test scores using a computer-based learning module (CBL) for OASIS nurse education. STUDY DESIGN: All L&D nurses were invited to complete a voluntary, self-assessment questionnaire inquiring about prior experience, training, and education and current clinical practice in caring for patients with OASIS. They were also asked to answer ten knowledge-based questions about OASIS. The primary outcome was change in pretest and posttest knowledge-based scores after completion of CBL. RESULTS: Forty-one L&D nurses voluntarily responded to the self-assessment survey. Of respondents, 20% answered they were "very comfortable", 48% "comfortable", 23% "neutral," and 8% "uncomfortable" for caring for women with OASIS post-delivery. Fifty-three percent of reported having no formal education in nursing school about OASIS and 35% reported no formal training while at work. The average pretest knowledge test score was 66.3% and 93.5% (p < 0.001) after completion of the CBL. CONCLUSIONS: Most L&D nurses in this study reported having very limited formal nursing education in OASIS. Regardless of this lack of formal training, the majority of L&D nurses in this sample described themselves as comfortable caring for patients with OASIS post-delivery. Completion of a CBL was associated with higher OASIS knowledge scores.

The Role of Transperineal Ultrasound for the Assessment of the Anorectal Angle and Its Relationship with Levator Ani Muscle Avulsion.

The relationship between the anorectal angle (ARA) and the levator ani muscle (LAM) is well known. In this study, we aimed to demonstrate that the ARA changes when LAM avulsion occurs after vaginal delivery. This was a secondary, observational retrospective study with data obtained from three previous studies. Using transperineal ultrasound, the presence of avulsion was assessed when abnormal insertion of the LAM was observed in three central slices. In addition, the ARA was assessed in the midsagittal plane (at rest, in Valsalva and at maximum contraction) as the angle between the posterior border of the distal part of the rectum and the central axis of the anal canal. The ARA was higher in patients with bilateral LAM avulsion than in patients without LAM avulsion at rest (131.8 ± 14.1 vs. 136.2 ± 13.8), in Valsalva (129.4 ± 15.5 vs. 136.5 ± 14.4) and at maximum contraction (125.7 ± 15.5 vs. 132.3 ± 13.2). The differences between both groups expressed as the odds ratio (OR) adjusted for maternal age were 1.031 (95% confidence interval (CI), 1.001-1.061; p = 0.041) at rest, 1.036 (95% CI, 1.008-1.064; p = 0.012) in Valsalva and 1.031 (95% CI, 1.003-1.059; p = 0.027) at maximum contraction. In conclusion, LAM avulsion produces an increase in the ARA at rest, during contraction and in Valsalva, especially in cases of bilateral LAM avulsion.

Immediate postpartum assessment of the anal sphincter by endovaginal ultrasound: An experimental study.

INTRODUCTION AND HYPOTHESIS: Obstetric anal sphincter injuries are frequently missed and carry a significant risk for the development of anal incontinence. Immediate postpartum endoanal ultrasound increases identification of these injuries but is rarely employed. We hypothesize that endovaginal ultrasound could be a feasible and easily available alternative sonographic tool to improve early diagnosis of anal sphincter tears. METHODS: We conducted a prospective experimental study including 160 primiparous women. Shortly after vaginal delivery, patients underwent clinical and sonographic perineal examinations. We analyzed the feasibility of anal sphincter assessment by endovaginal ultrasound and its potential contribution in the early diagnosis of anal sphincter injuries. RESULTS: Sonographic assessment of the anal sphincter was analyzable for 136 patients (85.0%). Causes of non-analyzability included air artifacts (6.9%), lack of distinction between the external anal sphincter and surrounding tissues (9.4%) and distortion artifacts (9.4%). Patients in the non-analyzable ultrasound subgroup were less likely to have delivered in a dorsal lithotomy position (62.5% vs. 85.3 %) and more likely to have had an episiotomy (33.3% vs. 14.0%), and their risk of sphincter injury was more frequently classified as "improbable" on clinical examination (91.7% vs. 61.0%). Ultrasounds were analyzable for 96.4% of patients clinically reported as having "possible" or "certain" sphincter injuries. The incidence of anal sphincter injury was 16.9% for clinical observation and 20.0% with associated sonographic examination. CONCLUSIONS: Endovaginal ultrasound could be used as a complementary tool in assessment of the anal sphincter in high-risk patients. Its feasibility and easy availability make this technique a promising tool for improving the management of anal sphincter tears.