Recurrent Uterine Rupture After Laparoscopic Surgery for Interstitial Ectopic Pregnancy

Introduction

Uterine rupture results when the uterine musculature gives way, usually at a weak point. Although it is most commonly seen during labor in women with previous uterine scars, it may also develop during the first or second trimester of pregnancy. Although scar rupture has been extensively studied, there is comparatively little information available regarding other causes of uterine rupture, including interstitial ruptures, which are associated with increased morbidity and mortality. A case of recurrent uterine rupture after laparoscopic treatment for recurrent ipsilateral ectopic pregnancy, including an interstitial pregnancy, is presented.

Case

A 31-year-old woman's first pregnancy in 2004 was a left tubal ectopic pregnancy, for which she underwent a laparoscopic partial left salpingectomy in France. This was followed by two early spontaneous miscarriages. In 2006, she was diagnosed to have an interstitial ectopic pregnancy in the left tubal stump. Laparoscopic excision of the ectopic pregnancy was performed using bipolar diathermy. The interstitial area was not sutured, as was the standard practice at that time, and histology confirmed the diagnosis of ectopic pregnancy.

The patient became pregnant again a few months later, and presented with bleeding in early pregnancy. A scan confirmed a normal viable intrauterine pregnancy. In January 2007, the patient was admitted at 24 weeks' gestation with acute abdominal pain and vomiting. Ultrasound examination was suggestive of uterine rupture with no fetal heart activity. An urgent midline laparotomy showed rupture of the uterus over the site of previous left interstitial ectopic pregnancy, with hemoperitoneum. The fetus was within the abdominal cavity with an intact amniotic sac, which was removed, and the uterus was closed in three layers using Vicryl sutures.

In November 2007, the patient was pregnant again, and a scan at 6 weeks' gestation showed a gestational sac high in the uterine cavity close to the left interstitium, with a rim of myometrium surrounding the pregnancy. The patient chose to continue the pregnancy under close supervision, but 2 weeks later presented with abdominal pain and vomiting. In view of her previous history, an emergency laparoscopy was performed. This revealed a hemoperitoneum, and subsequent laparotomy revealed a recurrent rupture at the left interstitium, which was then sutured with Vicryl in two layers.

At a follow-up scan in January 2008, the interstitial region appeared to have healed well, with myometrium measuring 14.3 mm near the fundus and 11.8 mm laterally with no obvious adhesions.

Results

The patient had a subsequent intrauterine pregnancy in 2008, which was very closely monitored with serial scan measurements of myometrial thickness. The left interstitium measured between 4 and 5 mm in thickness for the duration of the pregnancy. In view of previous uterine rupture, following administration of steroids for lung maturity, the patient delivered by elective cesarean section at 32 weeks' gestation. At cesarean section, dehiscence of the interstitial site was noted, which was oversewn with Vicryl. The patient and her child remain in good health.

Discussion

Uterine rupture occurs mostly during the intrapartum period, and is potentially catastrophic for both mother and fetus. Although much attention is paid to scar rupture following cesarean section and myomectomy, uterine rupture following interstitial ectopic pregnancies has not been properly studied.

Rupture of the uterus in cases of interstitial pregnancy may occur in those 20% that progress beyond 12 weeks' gestation. ¹ There is probably no direct association between tubal ectopic pregnancy and uterine rupture. However, partial resection of the fallopian tube in an ectopic pregnancy can pose the risk of development of a subsequent ectopic pregnancy in the stump or interstitial region, with subsequent risk of rupture of uterine horn. ² In a series of 32 interstitial pregnancies, the most common risk factors were tubal damage from previous ectopic pregnancy (40.6%), previous ipsilateral or bilateral salpingectomy (37.5%), conception after in vitro fertilization (34.4%), and history of sexually transmitted disease (25.0%). ³ There are also numerous cases of ipsilateral stump pregnancies after salpingectomy following laparoscopic management of ectopic pregnancy.^4–6 In view of this risk, total salpingectomy with resection of the interstitial portion of the tube is recommended to prevent implantation in the interstitial stump. ⁷ However in some cases, particularly following the use of the endoloop, this principle is not necessarily followed, leaving a stump with resulting higher risk for future interstitial pregnancy.

Management of interstitial pregnancy remains a challenge because of the risk of rupture. Laparotomy still remains the mainstay of management in cases of ruptured interstitial ectopic pregnancy, because of rapid and massive hemorrhage, but different laparoscopic techniques have been used for the treatment of interstitial pregnancy. Cornuostomy, which is analogous to linear salpingostomy, is used for some cornual ectopic pregnancies without removing the surrounding myometrium, and the defect is closed with a variety of methods to achieve hemostasis.^8–10 Laparoscopic cornual resection is the most common approach, which is the endoscopic version of the traditional cornual wedge resection.^11,12 Laparoscopic mini-cornual excision, on the other hand, is a relatively new technique, which involves de-roofing of the interstitial pregnancy by excision of the thinned-out myometrial mantle through an elliptical incision along the long axis of the interstitial pregnancy. The interstitial pregnancy is evacuated without creating a myometrial defect and need for sutures, which preserves the architecture and vascularity of the uterus by leaving the base intact. ¹³

The cumulative success rate with the use of various laparoscopic techniques from the available case reports and series in the literature is 85%, ⁷ but no long-term data are available to assess the risk of uterine rupture in subsequent pregnancies. The risk of rupture exists, because of a weakened cornual region following different techniques of repair. It can be argued that suturing may decrease the risk of future uterine rupture, and as such, many units have adopted this practice, but at the same time over-zealous suturing may compromise adequate blood supply, resulting in tissue ischemia. This in turn can impair healing and compromise the tensile strength of the interstitial region, potentially leading to uterine rupture. There are no randomized trials to guide the usefulness of suturing in interstitial ectopic pregnancies, although a few studies have compared linear salpingotomy with or without suturing. In contrast, excessive use of electrocautery may also cause significant damage to the myometrium, which can further weaken the interstitial region and increase the risk of uterine rupture with future pregnancies. ¹³ All surgical techniques claim high rates of success, but more objective assessment in terms of subsequent successful pregnancies and rates of uterine rupture should be used to determine effectiveness of management. Ideally, a randomized trial needs to be conducted to determine the long-term outcome and risk of uterine rupture with different surgical techniques. Organizing such a trial is likely to be a daunting task, because of the numbers needed to assess risk of uterine rupture. In the interim, a retrospective review of interstitial ectopic pregnancies may perhaps provide some answers until more direct evidence is available.

This particular case is unusual, in that there were two episodes of uterine rupture following the laparoscopic treatment of interstitial pregnancy. Whereas it is possible that the technique used, resection without suturing, may have directly contributed to the subsequent rupture, the interpregnancy interval may also have been a crucial factor. In the context of cesarean sections, it is known that a short interpregnancy interval is associated with a higher risk of rupture. The uterus requires a certain length of time to develop strong scar tissue, a process likely to be impeded by the distension that follows a subsequent pregnancy. It is, therefore, possible that the short interpregnancy interval in this case between the interstitial ectopic pregnancy and the subsequent pregnancies, that lead to rupture, did not provide adequate time for the uterus to develop a strong scar.

In response to this case, the authors have also modified their surgical approach to such ectopic pregnancies, which now involves laparoscopic suturing after resection. It is hoped that this will provide a stronger scar than one where the resected area has not been approximated. Although there is little evidence to back such a change, the dramatic nature of the recurrent ruptures in this case have instigated this change.

Conclusions

This case highlights the risk of uterine rupture following a previous interstitial ectopic pregnancy, but also demonstrates that despite recurrent ruptures, a successful pregnancy outcome can be achieved.