Comprehensive Management of Obstetric Rectal Buttonhole Tears: Insights From a Case Report and Literature Analysis

Introduction

Obstetric rectal buttonhole tears (ORBT) are rare obstetric complications whose true incidence has not been reported yet [1]. ORBTs are defined as perforations or lacerations of the rectal mucosa, accompanied by vaginal injury, with intact anal sphincters [2]. Their typical presentation is either with an intact perineum or with a low-degree perineal laceration [1,2]. As a result, they may go undiagnosed unless a thorough postpartum rectal examination is performed. ORBTs are not included in the widely recognized Sultan classification and there is no established consensus on their management [3–7]. Various repair techniques have been proposed, but the limited evidence and experience available make it challenging to standardize an approach. If unrecognized, they can lead to serious complications, such as rectovaginal fistula formation [8,9]. The present case report aims to address the literature gaps in 2 ways: firstly, describing an uncommon case of ORBT, which was overlooked after the inspection of the vagina and was diagnosed only after a digital rectal examination; and secondly, providing an updated literature review comparing the existing repair techniques. This case report and literature review underscore the importance of a rectal examination after a vaginal birth, suggest a comprehensive management of ORBT, and provide a cautionary example for all gynecologists.

Case Report

We present the case of a nulliparous patient admitted for labor induction at 40 weeks 6 days of gestation. The patient had 2 significant comorbidities: Grade I obesity and ongoing treatment with omalizumab (Xolair), with the most recent dose administered 18 days prior to the induction. Upon admission, the initial vaginal examination revealed a 1-cm cervix dilation. Labor induction was initiated due to post-term pregnancy and Grade I obesity using misoprostol, with a total dose of 25 μg, resulting in regular contractions. As labor progressed, epidural analgesia was administered when cervical dilation reached 2–3 cm. During the labor course, the patient developed secondary uterine inertia under epidural analgesia, necessitating augmentation with oxytocin. The first stage of labor lasted 7 hours 30 minutes. The second stage of labor lasted beyond 3 hours, with active pushing for 30 minutes. During this prolonged period, the cardiotocography (CTG) pattern deteriorated, showing variable decelerations. The patient subsequently underwent vacuum delivery of a female infant weighing 3430 g.

Following the delivery, the perineal examination revealed a left-sided vaginal laceration. A digital rectal examination was performed to assess the anterior rectal wall, and the sphincter tone; no proctoscope or sigmoidoscope was required. The digital rectal examination revealed a separate rectovaginal defect of approximately 2 cm in length, located 4–5 cm from the anus (Figure 1). The external and internal anal sphincter muscles were intact. Aside from primiparity, obesity, and vacuum delivery, the patient did not present any other typical risk factors for severe perineal trauma. The treatment with omalizumab is not considered a typical risk factor for ORBT. The repair of these lacerations was performed in the operation theater. A three-layer repair technique was chosen, to provide a robust tissue alignment and strength. The repair of the rectal wall was performed including the rectal mucosa, using continuous sutures with Vicryl 3-0 (Figure 2). This was followed by rectovaginal interposition with interrupted sutures using PDS 3-0 in the rectovaginal fascia. Subsequently, the vaginal tear was closed, and the perineum reconstructed in the usual manner, with additional continuous sutures using Vicryl 2-0. Postoperative antibiotics and laxatives were prescribed for 7 days.

Discussion

A comprehensive literature review, utilizing both MeSH terms and manual searching, identified 26 case reports, with a total of 26 patients with buttonhole tears (Table 1). Commonly identified risks for severe perineal trauma during childbirth include maternal factors such as advanced maternal age, diabetes, and primiparity, labor characteristics such as vaginal delivery following a caesarean section, prolonged second stage of labor, episiotomy, instrumental delivery, and induction of labor, and fetal factors such as fetal weight exceeding 4000 g [10]. Primiparity, instrumental delivery, and fetal weight over 4000 g are reported to be the most statistically significant risk factors [10]. In our case, we identified the following risk factors: primiparity, vacuum delivery, and a prolonged second stage of labor. The use of omalizumab is not considered a relevant risk factor according to the current literature.

The injury patterns had a considerable variety in their anatomical presentation. The majority (18 cases) exhibited compound injuries: 15 cases had concurrent iatrogenic episiotomies [1–9], 2 cases presented with additional second-degree perineal trauma [11,12], and 4 cases involved third-degree anal sphincter injuries [1,4,7,13]. In 3 cases, a fourth-degree perineal trauma was formed through the extension of the ORBT to visualize better the distal end of the trauma [5,8]. This approach carries a significant risk of compromising anal function, regardless of repair quality, and should not be considered for obstetric tears. The decision to extend a buttonhole tear into a complete fourth-degree laceration should be limited to situations where surgical exposure of the distal tear margin is inadequate. The remaining 9 cases, including our case, were documented as isolated rectovaginal buttonhole tears [2,3,8,10,14–17]. The size of buttonhole tear varied significantly, with longitudinal measurements ranging from 1 to 6 cm.

A detailed description of the repair technique was provided in 16 articles. Most case reports reported a 3-layer closure technique, including the closure of the rectal wall, the rectovaginal fascia, and the vaginal layer [1,2,4–8,11–14]. The terminology rectovaginal fascia varied among case reports, being referred in most of the cases as rectovaginal septum [1,2,4,6,8,11–14]. Six articles reported a 2-layer closure (closure of the rectal wall and closure of the vaginal laceration) [1,3,8,15–17] and 2 case reports did not specify which type of repair was used [3,8]. Unfortunately, the reasons for selecting one technique over the other are not specified in the reviewed case reports, although the 3-layer technique appears to be more frequently used. In our case, we chose the 3-layer closure technique because it aligns with established practices in colorectal surgery, particularly in rectovaginal fistula repair, provides better tissue alignment and strength, and has shown effectiveness in preventing recurrence [10].

The reported suturing techniques show some discrepancies: 33.3% (9/27) of the reported studies, including our study, recommend using a continuous, non-locking suture for the rectal wall [1,2,4,8,11,12,16], and 22.2% (6/27) used interrupted sutures [1,5,6,8,14,17]. The suture materials used for repair were consistent across cases – Vicryl 3-0 or 2-0 was the most utilized material for the rectal wall. A repair of the rectovaginal fascia was documented in 13 case reports (including our case report): 8 used Vicryl, 3 PDS, 1 used Monocryl, and 1 did not specify the material. In our case we used PDS monofilament sutures because they have been suggested to provide a more adequate support in the rectovaginal fascia due to their extended time of absorption [18]. For the vaginal skin, continuous Vicryl 2-0 was used in all cases where the suture type was reported.

The number of reported cases of ORBT has increased in recent years, with a 3-fold increase in the documented cases in the last 4 years compared to the reported cases prior to 2020. This rise may be attributed to greater awareness among physicians and more thorough vaginal and rectal examinations. Once detected and repaired, despite variations in technique, a satisfactory tear closure and a subsequent recovery can be achieved. Based on our clinical experience and the reviewed articles, we suggest a 3-layer closure of the ORBT to minimize the risk of recurrence and the achieve a better tissue adaptation. A rectal wall closure, with continuous or interrupted Vicryl sutures, should be followed by repair of the rectovaginal fascia with PDS and repair of the vaginal wall. The discrepancy in the suturing techniques of the rectal wall do not allow us to draw a firm conclusion regarding the preferred suturing technique.

Conclusions

Obstetric rectal buttonhole tears are rare, with only 27 cases indentified in the present review. To date, there have been 2 similar reviews of the literature, with a total of 12 and 16 cases, respectively. Our review adds 11 more cases, including our case, and shows a comprehensive clinical presentation and management of ORBT. The rarity of the reported cases, the predominance of case series and case reports in the reviewed studies, and the variability in repair techniques make it difficult to determine the best repair technique and management strategy. The current analysis supports a 3-layer closure because it optimizes tissue alignment and strength.

To overcome these gaps, digital postpartum rectal examination should be integrated into obstetric training programs to improve case detection. Furthermore, comparative studies are needed to evaluate the repair techniques and different postoperative care protocols. Such efforts will improve the long-term functional outcomes and will lead to best-practice management for ORBT.