Laparoscopic excision of a noncommunicating rudimentary horn containing an ongoing pregnancy with cardiac activity: a structured minimally invasive approach.

OBJECTIVE: To describe the diagnostic process and a structured, stepwise laparoscopic excision of a noncommunicating rudimentary uterine horn containing an ongoing pregnancy with cardiac activity, demonstrating how expert transvaginal and 3-dimensional ultrasound can guide early diagnosis and safe minimally invasive surgical management.

DESIGN: Detailed case report with diagnostic imaging, stepwise operative video, and structured 5-step surgical technique.

SUBJECTS: A 31-year-old G2P1 woman with a history of a prior low-transverse cesarean delivery presented to the emergency department with suspected ectopic pregnancy. She was hemodynamically stable with no active vaginal bleeding or acute abdominal pain. Detailed history revealed asymptomatic presentation; routine first-trimester ultrasound performed for dating had raised suspicion of an ectopic pregnancy. On physical examination, the cervix was single and the os closed; bimanual examination revealed mild adnexal tenderness on the left but no peritoneal signs. TVUS performed by a radiologist with expertise in complex pelvic anomalies demonstrated a right unicornuate uterus with normal endometrial thickness and no intrauterine gestational sac. A separate, left-sided gestational sac measuring 20 mm was identified, surrounded by a thick myometrial mantle (approximately 15 mm), with no continuity to the endometrial cavity or main uterine cornu. The gestational sac contained a yolk sac and a fetal pole, with a crown-rump length consistent with approximately 7 weeks and 6 days of gestation, and demonstrated confirmed cardiac activity. Color and spectral Doppler demonstrated robust arterial flow surrounding the gestational sac, indicating a rich vascular supply to the rudimentary horn. Three-dimensional ultrasound reconstructions confirmed the uterine anatomy as unicornuate with a noncommunicating rudimentary horn. Given the early gestational age, hemodynamic stability, clear diagnostic features on expert transvaginal and 3D ultrasound (single cervix, noncommunicating sac, robust vascularity, known unicornuate anatomy), and the time-sensitive nature of the condition, same-day laparoscopic management was chosen. Preoperative magnetic resonance imaging (MRI) was not pursued because transvaginal ultrasound provided clear anatomic delineation, including characterization of the attachment between the rudimentary horn and the unicornuate uterus, assessment of vascular supply, and evaluation of surrounding pelvic anatomy for surgical planning. Medical management with methotrexate was considered inappropriate, as it was unlikely to provide definitive treatment and carried a risk of treatment prolongation and unexpected rupture. This management aligns with published case series where expert ultrasound diagnosis is confirmed intraoperatively, and MRI is reserved as an adjunct in cases of diagnostic uncertainty (1-3).

EXPOSURE: Step 1: Exposure and Anatomical Identification. The uterus was examined in situ; the right unicornuate uterus and left rudimentary horn were identified. The rudimentary horn appeared markedly vascular, measuring approximately 6 cm. The left fallopian tube was identified as a small, separate structure. Both ureters were clearly identified. Careful inspection ruled out peritoneal fluid or blood. Step 2: Mobilization of the Gravid Horn by Division of the Utero-Ovarian Ligament. The left ureter was identified transperitoneally under direct visualization as it coursed beneath the infundibulopelvic ligament. The left utero-ovarian ligament was identified and divided using the Ligasure device. The left ovary was preserved in situ. Step 3: Opening of the Broad Ligament. The round ligament on the left was divided to improve exposure. The bladder was gently dissected off the lower uterine segment and the rudimentary horn attachment site to provide clear visualization of the lower border of the horn-to-uterus junction. Step 4: Vasopressin-Assisted Devascularization and Skeletonization of the Horn-to-Uterus Junction. Dilute vasopressin (2 units in 10 mL normal saline) was injected into the myometrium surrounding the attachment of the rudimentary horn to reduce vascularity. Following a 2-3-minute waiting period, the vascular pedicles along the horn-to-uterus junction were identified, isolated, and carefully coagulated using the Ligasure device. The investing peritoneum and myometrial attachments were progressively skeletonized. Step 5: Excision of the Rudimentary Horn, Tube Removal, Specimen Retrieval, and Repair. Once fully mobilized and devascularized, the rudimentary horn and ipsilateral fallopian tube were excised sharply from the junction with the unicornuate uterus. The specimen was placed in an endoscopic retrieval bag (to contain pregnancy contents and minimize intra-abdominal spillage). The left ureter was reidentified with clearly visible peristalsis, confirming intact function and anatomy. The defect in the uterine myometrium at the horn-to-uterus junction was closed in a single layer using a 2-0 absorbable barbed running suture. The specimen was retrieved through the umbilical trocar.

MAIN OUTCOME MEASURES: Diagnostic accuracy of expert transvaginal and 3D ultrasound, intraoperative safety and feasibility of laparoscopic excision (estimated blood loss, operative time, intraoperative complications), and postoperative recovery including length of hospital stay.

RESULTS: Preoperative expert transvaginal and 3D ultrasound findings were fully concordant with intraoperative anatomy. No intraoperative complications occurred. Estimated operative blood loss was 30 mL. Total operative time was approximately 45 minutes. The patient was discharged on postoperative day 1 in stable condition. No postoperative complications were documented during a 6-week follow-up period. The patient reported minimal postoperative pain and early return to normal activities.

CONCLUSION: This case demonstrates that early, accurate diagnosis of rudimentary horn pregnancy can be achieved using expert transvaginal and 3D ultrasound at high-volume centers, avoiding diagnostic delay and enabling same-day minimally invasive management. In the context of hemodynamic stability and clear anatomic delineation, laparoscopic excision with a structured stepwise approach achieves excellent outcomes with minimal morbidity.