Can transperineal ultrasound improve the diagnosis of obstetric anal sphincter injuries?

Background: Women with missed Obstetric anal sphincter injuries (OASIs) are at an increased risk of anal incontinence. Objective: To assess the accuracy of 3D Transperineal Ultrasound (TPUS) compared with clinical examination for detecting OASIs. Design: Prospective Observational longitudinal cohort study. Setting: District General Hospital, UK. Population or sample: Women undergoing their first vaginal delivery immediately postpartum. Methods: Perineal trauma was initially assessed by accouchers and women were then re-examined by a trained research fellow. A 3D TPUS was performed immediately after delivery before suturing to look for OASIs. Main outcome measures: OASIs on clinical examination and on TPUS Main Results: Two hundred and sixty-four women participated and two hundred and twenty-six (86%) delivered vaginally. Twenty-one (9%) sustained OASIs. Six (29%) of these tears were missed by the accoucher but were identified by the trained research fellow. TPUS identified 19 of the 21 (90.5%) OASIs. One percent (n = 2) had sonographic appearances of an anal sphincter defect and were not seen clinically. The positive and negative predictive of TPUS to detect OASIs were 91% and 99% respectively. TPUS identified 91% of OASIs compared to 71% detected by the accoucher. However, this was not statistically significant. Conclusions: More OASIs were identified on TPUS compared to examination. TPUS may have role in improving the detection rate of OASIs. Considering immense training and financial implications of using TPUS, attention needs to be focused on training to accurately identify anal sphincter defects on clinical examination. Funding:none Keywords: transperineal ultrasound imaging, obstetric anal sphincter injury

Impact of residual defect of anal sphincter on patient’s quality of life

Summary Aim: The aim of this retrospective study is to correlate the presence of residual anal sphincter defect with the quality of life of patients after vaginal delivery complicated with obstetrical anal sphincter injury. Study group and methods: Patients diagnosed with obstetrical anal sphincter injury are dispensed at our urogynecological unit, with a mean follow-up period of 37 months. Two investigators blinded to the results of clinical symptoms evaluated archived ultrasound volumes taken for the presence of residual anal sphincter defects that were later correlated with the St. Mark’s Incontinence Score. Results: The group comprises of 181 patients diagnosed with an obstetrical anal sphincter injury who underwent ultrasound examination of anal sphincter at three post-partum months. The questionnaires were completed by 118 patients (65.2% of all patients). A residual sphincter defect was diagnosed in seven cases (5.9%). In the group with residual defects, fecal urgency (lack of ability to defer defecation) was present in 57.1%. In the group without residual anal sphincter defects, fecal urgency was present in 12.6%. This difference is significant (< 0.001) with the contingency coefficient 0.291. Conclusions: In conclusion, the presence of residual anal sphincter defect increases the probability of fecal urgency.

Effect of a subsequent pregnancy on anal sphincter integrity and function after obstetric anal sphincter injury (OASI)

Introduction and hypothesis Endoanal ultrasound (EAUS) and anal manometry are used in the assessment women with a history of obstetric anal sphincter injury (OASI), both postpartum and in a subsequent pregnancy, to aid counselling regarding mode of delivery (MOD). Methods A prospective observational study between 2012 to 2020 was completed. Women were reviewed 3 months postpartum following OASI and in the second half of a subsequent pregnancy. Anorectal symptoms were measured using the validated St Mark’s Incontinence Score (SMIS: asymptomatic to mild symptoms = ≤ 4). Anal manometry (incremental maximum squeeze pressure [iMSP: normal = > 20 mmHg]) and EAUS (abnormal = sphincter defect > 1 h in size) were performed. Results One hundred forty-six women were identified and 67.8% had an anal sphincter defect ≤ 1 h in size postnatally. In those with a defect ≤ 1 h, postpartum mean iMSP and SMIS significantly improved in a subsequent pregnancy (p = 0.04 and p = 0.01, respectively). In women with a defect > 1 h, there was no significant difference between the mean iMSP or SMIS score postnatally compared to a subsequent pregnancy. At both time points, significantly more women had an anal sphincter defect ≤ 1 h and SMIS of ≤ 4 (p = 0.001 and p < 0.001 respectively) compared to those with a defect < 1 h. In addition, significantly more women had an anal sphincter defect ≤ 1 h and iMSP ≥ 20 mmHg (p < 0.001). Overall, out of the 146 women included in this study, 76 (52.1%) with a defect ≤ 1 h also had an iMSP ≥ 20 mmHg and SMIS ≤ 4 at 3 months postpartum. Conclusions Women who remain asymptomatic with normal anal manometry and no abnormal sphincter defects on EAUS postnatally do not need to have these investigations repeated in a subsequent pregnancy and can be recommended to have a vaginal delivery. If our protocol was modified, over half of the women in this study could have had their MOD recommendation made in the postnatal period alone.