Interstitial Ectopic Pregnancy: Laparoscopic Cornuostomy.

STUDY OBJECTIVE: To demonstrate and discuss the technique of cornuostomy for surgical management of interstitial ectopic pregnancy.

DESIGN: Stepwise demonstration of the technique with narrated video footage.

SETTING: Tertiary referral center in Manchester, United Kingdom.

INTERVENTION: Interstitial ectopic pregnancies are rare but are associated with a higher mortality rate than other ectopic pregnancies [1,2]. It occurs when the fertilized embryo implants in the interstitial portion of the fallopian tube traversing the vascularized myometrium. When undiagnosed they present late in the second trimester associated with rupture and catastrophic bleeding, with a mortality rate of 2% to 2.5%.2 Diagnosis requires a degree of vigilance from the ultrasound operator because it is commonly misdiagnosed as intrauterine pregnancies. Surgical management options include laparoscopic cornual resection or cornuostomy. There is no consensus on the optimal surgical technique but cornuostomy is a more conservative approach associated with less disruption to uterine anatomy and loss of myometrium [3,4]. A 22-year-old gravida 4 woman presented at 7 weeks' gestation with right iliac fossa pain. Initial serum human chorionic gonadotropin was 18 136 IU/L. Transvaginal ultrasound scan showed an empty endometrial cavity and an echogenic "donut"-shaped mass within the right interstitial space, within the uterine serosa but outside the endometrial cavity (Supplemental Video 1). At laparoscopy the diagnosis of a right interstitial ectopic pregnancy was confirmed (Supplemental Video 2). Vasopressin 20 IU diluted in 80 mL of normal saline was injected around the base of the ectopic pregnancy. Monopolar diathermy was used to incise the overlying serosa followed by hydrodissection to separate the ectopic gestational sac from the myometrial attachment. The resulting defect was inspected and closed in 2 layers. Total operating time was 46 minutes.

CONCLUSION: Although there is no clear evidence to guide the management of all interstitial ectopic pregnancies, an individualized approach taking into account the woman's previous history and future fertility plans and wishes is essential. In this case, given the woman's previous contralateral salpingectomy and her wishes for a conservative approach, a laparoscopic cornuostomy was likely the best option.