Ovarian torsion
| Ovarian torsion | |
|---|---|
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| Arteries of the female reproductive tract: uterine artery, ovarian artery and vaginal arteries. (Ovary and ovarian artery visible in upper right.) | |
| Classification and external resources | |
| ICD-10 | N83.5 |
| ICD-9-CM | 620.5 |
| DiseasesDB | 31120 |
| eMedicine | article/795994 |
Ovarian torsion (OT) refers to the rotation of the ovary at its to such a degree as to occlude the ovarian artery and/or vein.
Ovarian torsion accounts for about 3% of gynecologic emergencies. The incidence of ovarian torsion among women of all ages is 5.9 per 100,000 women, and the incidence among women of reproductive age (15–45 years) is 9.9 per 100,000 women. In 70% of cases, it is diagnosed in women between 20 and 39 years of age. The risk is greater during pregnancy and in menopause. Risk factors include increased length of the ovarian ligaments, pathologically enlarged ovaries (more than 6 cm), ovarian masses or cysts, and enlarged corpus luteum in pregnancy.
Patients with ovarian torsion often present with sudden onset of sharp and usually unilateral lower abdominal pain, in 70% of cases accompanied by nausea and vomiting.
Use of Doppler ultrasound in the diagnosis has been suggested. However, doppler flow is not always absent in torsion – the definitive diagnosis is often made in the operating room.
The development of an ovarian mass is related to the development of torsion. In the reproductive years, regular growth of large corpus luteal cysts are a risk factor for rotation. The mass effect of ovarian tumors is also a common cause of torsion. Torsion of the ovary usually occurs with torsion of the fallopian tube as well on their shared vascular pedicle around the broad ligament, although in rare cases the ovary rotates around the mesovarium or the fallopian tube rotates around the mesosalpinx. In 80%, torsion happens unilaterally, with slight predominance on the right.
Ovarian torsion is difficult to diagnose accurately, and operation is often performed before certain diagnosis is made. A study at an obstetrics and gynaecology department found that preoperative diagnosis of ovarian torsion was confirmed in only 46% of patients.Gynecologic ultrasonography is the imaging modality of choice.
Lack of ovarian blood flow on Doppler sonography seems to be a good predictor of ovarian torsion. Women with pathologically low flow are more likely to have OT (77% vs. 29% in a study). The sensitivity and specificity of abnormal ovarian flow for OT are 44% and 92%, respectively, with a positive and negative predictive value of 78% and 71%, respectively. Specific flow features on Doppler sonography include:
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