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

Abstract

Purpose The aim of this study was to examine whether OASIS, and its extent, can be confirmed or excluded using transperineal ultrasound (TPUS). A further objective of this study was to monitor the healing process over a period of 6 months and to establish a connection between the sonographic appearance of obstetric anal sphincter injury (OASIS) and anal incontinence. Materials and methods In this retrospective clinical study, women with OASIS who gave birth between March 2014 and August 2019 were enrolled. All the patients underwent TPUS 3 days and 6 months after delivery. A GE E8 Voluson ultrasound system with a 3.5–5 MHz ultrasound probe was used. The ultrasound images showed a third-degree injury, with the measurement of the width of the tear and its extent (superficial, partial, complete, EAS and IAS involvement). A positive contraction effect, a sign of sufficient contraction, was documented. Six months after delivery, a sonographic assessment of the healing (healed, scar or still fully present) was performed. A Wexner score was obtained from each patient. The patients’ medical histories, including age, parity, episiotomy and child’s weight, were added. Results Thirty-one of the 55 recruited patients were included in the statistical evaluation. Three patients were excluded from the statistical evaluation because OASIS was excluded on TPUS 3 days after delivery. One patient underwent revision surgery for anal incontinence and an inadequately repaired anal sphincter injury, as shown sonographic assessment, 9 days after delivery. Twenty patients were excluded for other reasons. The results suggest that a tear that appears smaller (in mm) after 3 days implies better healing after 6 months. This effect was statistically significant, with a significance level of alpha = 5% (p = 0.0328). Regarding anal incontinence, women who received an episiotomy had fewer anal incontinence symptoms after 6 months. The effect of episiotomy was statistically significant, with a significance level of alpha = 5% (p = 0.0367). Conclusion TPUS is an accessible, non-invasive method for detecting, quantifying, following-up and monitoring OASIS in patients with third-degree perineal tears. The width, as obtained by sonography, is important with regard to the healing of OASIS. A mediolateral episiotomy seems to prevent anal incontinence after 6 months.

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

“…Antenatal perineal massage, warm compresses during the active phase of the second stage of labor, perineal protection at fetal head crowning, and the all/four maternal birthing position have shown a protective effect [ 7 ], while the role of episiotomy remains controversial [ 8 , 9 , 10 ]. OASI carries a risk of developing anal incontinence between 20% and 60% [ 11 , 12 ], with a major negative impact on the quality of life as a result of its physical, psychological, and social implications [ 13 , 14 ]. If anal incontinence persists after primary repair or as a result of tear dehiscence, secondary repair may be indicated [ 15 , 16 ].…”

“…In recent years, 3D transperineal ultrasound (TPUS) has been successfully used to diagnose OASIs and monitor the healing process [ 17 ], achieving good sensitivity and high specificity in identifying EAS and IAS defects, respectively [ 18 ]. It also has the advantages of lower cost, greater availability in gynecological clinics, and higher tolerability [ 12 ] than endoanal ultrasound (EAUS), which has been the gold standard so far [ 14 , 19 ].…”

“…Before surgery, a TPUS was performed (Voluson™ S10 Expert, GE Medical Systems, Zipf, Austria). The 3.5–5 MHz ultrasound probe was placed at the anal opening of the patient with 10°–20° inclination toward the ventral direction to locate the anal sphincter [ 12 ]. During the examination of the anal sphincter using TPUS, four layers were visualized (from the inner to the outer part): the lumen of the anal canal, the mucous membrane, the IAS hypoechogenic ring, and the EAS hyperechogenic ring ( Figure 1 ).…”

“…Although EAUS remains the gold standard, it does not allow for resting sphincter examination, is scarcely available in gynecological clinics, and has a high cost [ 25 ]. More recently, TPUS has been demonstrated as an effective alternative method to identifying OASIs and monitor the healing process over time [ 12 , 17 ]. In particular, we believe that all patients symptomatic for postpartum AI should receive this diagnostic assessment, which is less expensive, more available at gynecological clinics, and better tolerated in comparison to EAUS [ 12 ].…”

“…More recently, TPUS has been demonstrated as an effective alternative method to identifying OASIs and monitor the healing process over time [ 12 , 17 ]. In particular, we believe that all patients symptomatic for postpartum AI should receive this diagnostic assessment, which is less expensive, more available at gynecological clinics, and better tolerated in comparison to EAUS [ 12 ]. Furthermore, in this report, we confirmed that TPUS allows for early identification of postpartum residual EAS defect, without the need for waiting for perineal edema resolution [ 26 ].…”