Ovarian Torsion during Pregnancy

Gary Ventolini, MD

Laura Hunter, MD

Dale Drollinger, MD

William W. Hurd, MD

Department of Obstetrics and Gynecology

Dayton, Ohio

Case Presentation

A 28-year-old woman presented to the emergency department during her first pregnancy with acute onset of excruciating pain in the left lower-abdominal quadrant. The pain started 6 hours earlier, waking her from sleep early in the morning. Ahot bath did not relieve the symptoms. The patient described her pain as nonradiating, sharp, and 10 out of 10 in severity. She reported no vaginal bleeding or discharge, nausea, vomiting, fever, diarrhea, or constipation. Her general and gynecologic history was noncontributory. She had no history of recent illnesses, urinary complaints, or treatment for infertility.

Physical examination showed she was diaphoretic. Her vital signs were remarkable for a blood pressure of 90/55 mm Hg and a pulse of 88 beats/min. Abdominal examination revealed a palpable left lowerquadrant mass to the level of the umbilicus, with voluntary guarding but no rebound or peritoneal signs. Pelvic examination revealed a 16-week sized uterus, with a closed cervix, and a tender 10-cm left adnexal mass.

Laboratory results were normal. Transabdominal sonography performed at the bedside visualized a normal fetus in utero with a gestational age of 16 weeks. In the left adnexa, a large, 11 cm x 6 cm simple cyst was seen arising from the left ovary. The right ovary appeared normal, and no free fluid was seen in the cul-de-sac. Color flow Doppler was not available.

Her blood pressure did not change in response to a bolus of intravenous fluid. With a presumptive diagnosis of ovarian torsion, the patient was brought to the operating room, where general anesthesia and endotracheal intubation were carried out. Because the mass extended above the umbilicus, laparotomy was performed instead of laparoscopy.

On entry into the abdominal cavity with a midline incision, a congested 14-cm left ovary was found to be twisted around its ovarian pedicle 1.5 rotations (Figure 1). After untwisting the ovarian pedicle, the ovary returned to its normal color and showed no signs of hemorrhage or necrosis. It contained a 14-cm simple-appearing cyst. The cyst was excised in a usual fashion (Figure 2). On the inner surface of the cyst wall lining, an area of dense, white papillary excrescences was noted. Frozen section performed during surgery and subsequent permanent sections revealed a diagnosis of benign cystadenofibroma.

The patient recovered from her surgery without problems and was discharged on the third postoperative day. The remainder of her pregnancy was unremarkable, and she delivered a healthy infant vaginally at term.

Discussion

Ovarian torsion is an uncommon cause of acute abdominal pain in nonpregnant women but is more common during pregnancy. When present, it is often associated with severe pain.

Etiology and pathophysiology

Ovarian torsion is the total or partial rotation of the adnexa around its vascular axis. Venous or lymphatic blockade could result in potentially massive enlargement of the ovary caused by continued arterial inflow to the ovary without venous outflow. Eventually, if undiagnosed and untreated, arterial stasis can lead to hemorrhagic infarction and necrosis of the ovarian stroma.

Unlike in our patient, ovarian torsion occurs more often in the right adnexa, presumably because the sigmoid colon limits the mobility of the left ovary.¹ Almost without exception, torsion occurs when the ovary is enlarged secondary to cysts or neoplasms. The majority of cysts are functional. The most frequent nonfunctional neoplasms are serous or mucinous cystadenomas, benign cystic teratomas ("dermoids"), and ovarian fibromas. Malignant tumors occur in less than 6% of cases.² Serous cystadenofibromas, as in our patient, are relatively common, accounting for approximately 8% of ovarian neoplasms.³

The incidence of ovarian torsion rises 5-fold during pregnancy to approximately 5 per 10,000 pregnancies.⁴ Its most common cause in pregnancy is a corpus luteum cyst, which usually regresses spontaneously by the second trimester.⁵ Ovarian torsion, therefore, occurs most frequently in the first trimester, occasionally in the second, and rarely in the third.⁶

Clinical manifestations and diagnosis

Ovarian torsion can sometimes be difficult to diagnose in pregnancy. The most common clinical presentation is acute onset of severe, colicky unilateral pelvic pain that is usually unremitting but can wax and wane in cases of incomplete, intermittent torsion. Fall in blood pressure and heart rate is another common response to visceral and deep somatic nociception.⁷

Ultrasound is the diagnostic modality of choice and will most often reveal a unilateral ovarian enlargement that appears solid, cystic, or complex, with or without fluid collections in the pouch of Douglas. Color Doppler sonography often depicts an enlarged ovary without perfusion of the parenchyma.⁸ In the second and third trimesters of pregnancy, the ovaries are sometimes difficult to visualize ultrasonographically, because they are displaced from the pelvis by the enlarging uterus. If the ovaries are not clearly visualized with vaginal or abdominal ultrasound, magnetic resonance imaging (MRI) can be used to avoid the risk of ionizing radiation. MRI findings consistent with ovarian torsion include a thick edematous pedicle and ovary, lack of enhancement, and signal intensities consistent with hemorrhage.⁹

Treatment

Expedient surgery is a requisite treatment for ovarian torsion. The decision to proceed to surgery during pregnancy is somewhat complex, since the well-being of both mother and fetus must be taken into account. The risk of any surgery to the pregnancy will depend on the gestational age. In the first trimester, when ovarian torsion most often occurs in pregnancy, the risk of fetal loss is the smallest with modern anesthetic techniques.¹⁰ Surgery during the second or third trimester is associated with the risk of premature labor. In one study, preterm labor occurred in 26% of women who had surgery during the second trimester and in 82% of those who had surgery during the third trimester.¹⁰

Several approaches can minimize the risk of premature labor. Regional anesthesia should be used whenever possible to decrease postoperative pain and the subsequent release of catecholamines, which can stimulate uterine contractility.¹¹ Continued epidural infusion of narcotics for up to 72 hours is an excellent way to minimize postoperative pain.¹²

Uterine monitoring during surgery is controversial, since fetuses appear to do well as long as the mother is well oxygenated.¹³ In a maternal crisis, resuscitation of the mother rather than delivery is the ideal approach. Uterine monitoring in the immediate postanesthesia period for patients in the second or third trimester is an important method for the early detection of regular uterine contractile activity.

Adnexal masses (Table) are among the most common indications for surgery during pregnancy.¹⁰ For years, the treatment of choice for ovarian torsion was salpingooophorectomy, taking special care to avoid untwisting the ovarian pedicle to prevent emboli and toxic substances related to hypoxia from entering the peripheral circulation. However, reestablishing ovarian circulation by untwisting the ovarian pedicle has recently been shown to result in viable ovarian tissue on the affected side, with no systemic complications reported to date.^9,14,15 Conservative treatment appears to be warranted to preserve fertility, even for adnexa that initially appear nonviable and purple or black in color.^16,17

A major consideration is whether the surgery can be performed by laparoscopy or by laparotomy. In the nonpregnant patient and during the first trimester of pregnancy, ovarian torsion can usually be approached laparoscopically.¹⁵ Although untwisting the ovarian pedicle is relatively simple, ovarian cystectomy requires more advanced laparoscopic skills. In the second or third trimester, the combined size of the pregnant uterus and enlarged ovary usually make laparotomy the approach of choice, despite the associated increased pain and risk of wound complications.

In the presence of an ovarian cyst, a simple cystectomy can be performed in the absence of overt malignancy. When possible, the entire ovary is delivered from the abdominal cavity and surrounded by moist laparotomy pads to avoid intra-abdominal spillage of cyst contents should it rupture. The thin ovarian capsule is carefully incised, usually with a scalpel. Blunt dissection is used to separate the cyst from the ovarian tissue. Electrosurgery can be used on the internal ovarian surfaces for hemostasis but should not be used near the cyst wall to minimize the risk of cyst rupture.

Rupture is inevitable in some ovarian cysts, particularly in endometriomas and functional cysts, such as luteomas. If a dermoid is accidentally ruptured, every effort should be made to avoid spilling the very irritating sebaceous contents into the peritoneal cavity. If this occurs, prolonged peritoneal irrigation with warmed saline will prevent peritonitis. Likewise, if the "chocolate" contents of an endometrioma or the fluid content of a potentially malignant cyst spills within the peritoneal cavity, prolonged irrigation with warmed saline is judicious. It remains to be determined if these precautions avoid the detrimental effect of intraoperative rupture on stage I ovarian cancer.¹⁸

Regardless of rupture, all cysts should be completely opened after removal and the internal surface of the cyst wall examined for excrescences. When present, microscopic examination of frozen sections can help determine if intraoperative staging is required. In all cases, definitive diagnosis must await careful examination of permanent sections.

The ovary does not require precise reconstruction as was thought in the past. Reapproximation with internal sutures may help subsequent reformation of the normal ovarian profile, but sutures on the external ovarian surface should be avoided to minimize the subsequent risk of adhesion formation.¹⁹

Conclusion

Ovarian torsion is relatively uncommon in the second trimester of pregnancy. Diagnosis can usually be made on the basis of the characteristic clinical presentation in conjunction with ultrasound evidence of a unilaterally enlarged adnexal mass. Treatment options are limited to surgery, either by laparoscopy or laparotomy, but the former becomes more difficult in the second trimester.

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