Obstetric anal sphincter injuries (OASIS): using transperineal ultrasound (TPUS) for detecting, visualizing and monitoring the healing process

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.

Martius fat pad flap procedure for management of obstetric rectovaginal fistula: A case report

Obstetric trauma is a risk factor for rectovaginal fistula, and it is a challenge for both patients and surgeons. In this case report, we describe the surgical technique of the Martius fat pad flap for repair of a rectovaginal fistula. The patient was a 30-year-old woman, para 1, with a previous spontaneous vertex vaginal delivery of a 2500-g male baby at 37 weeks of gestation. There was a history of arrest of descent, and the patient had a third-degree perineal laceration that was repaired in the operating room. Twelve days after delivery, the patient complained about fecal vaginal discharge and was diagnosed with a rectovaginal fistula. Physical examination revealed a rectovaginal fistula with a 2 cm diameter and located 1 cm from the hymen. The tone of the external anal sphincter was within normal limits, which was confirmed with transperineal ultrasound scan. The repair was done 3 months after the previous repair in order to allow for the restoration of tissue integrity and the complete healing of the previous wound. The rectovaginal fistula was repaired with a Martius fat pad flap in a transperineal approach. After 60 days of follow-up, the wound involving the labia majora and the fistula were healed completely.

Neonatal head circumference as a risk factor for obstetric anal sphincter injuries: a systematic review and meta-analysis

OBJECTIVE

Between 53% and 79% of women will sustain some degree of perineal laceration during vaginal delivery. Third- and fourth-degree perineal lacerations are known as obstetric anal sphincter injuries. Timely diagnosis and prompt treatment of obstetric anal sphincter injuries can help to prevent the development of severe consequences like fecal incontinence, urinary incontinence, and rectovaginal fistula. Neonatal head circumference is routinely measured postpartum but is often not mentioned as a risk factor for obstetric anal sphincter injuries in clinical guidelines. Thus far, no review article on the risk factors for obstetric anal sphincter injuries has discussed the role of neonatal head circumference. This study aimed to review and analyze the relationship between head circumference and the occurrence of obstetric anal sphincter injuries among previous studies to conclude whether head circumference should be recognized as an important risk factor.

DATA SOURCES

Through study screening on Google Scholar, PubMed, Scopus, and Science Direct for articles published between 2013 to 2023, followed by assessment of eligibility, this study ended up reviewing 25 studies, 17 of which were included in the meta-analysis.

STUDY ELIGIBILITY CRITERIA

Only studies that reported both the neonatal head circumference and the occurrence of obstetric anal sphincter injuries were included in this review.

METHODS

The included studies were appraised using the Dartmouth Library risk of bias assessment checklist. Qualitative synthesis was based on the study population, findings, adjusted confounding factors, and suggested causative links in each study. Quantitative synthesis was conducted using calculation and pooling of odds ratios and inverse variance using Review Manager 5.4.1.

RESULTS

A statistically significant association between head circumference and obstetric anal sphincter injuries was reported in 21 of 25 studies; 4 studies reported that head circumference was a true independent risk factor. A meta-analysis of the studies that reported neonatal head circumference as a dichotomous categorical variable with a cutoff point of 35±1 cm yielded statistically significant pooled results (odds ratio, 1.92; 95% confidence interval, 1.80-2.04).

CONCLUSION

The risk for obstetric anal sphincter injuries increased as the neonatal head circumference increased-this should be considered in decision-making during labor and postpartum management to attain the best outcome.