- Rotation (complete or partial) of the ovarian vascular pedicle on its long axis; perhaps more accurately referred to as “adnexal torsion” because the fallopian tube is commonly involved
- Torsion can lead to impaired vascular supply to the ovary, potentially progressing to necrosis.
- The hallmark symptom is pelvic/abdominal pain, sometimes cyclic; associated symptoms include nausea (70%), vomiting (45%), flank pain, and fever (20%) (1).
- Torsion of a normal ovary can occur. However, up to 94% of cases of ovarian torsion involve a mass in the ovary (or adnexa) such as a cyst or neoplasm.
- Adnexal torsion can be difficult to diagnose, with only approximately 44% diagnosed correctly on first presentation (1).
Torsion is the fifth most common gynecologic emergency (2.7%) and accounts for 15% of all surgically treated adnexal masses (2).
Etiology and Pathophysiology
- Adnexal blood supply comes from both the uterine and ovarian vessels.
- Torsion commonly cuts off blood supply from one source. However, the ovary often continues to be perfused by the other source.
- Although the venous drainage from the ovaries is a very low-pressure system, the arterial supply to ovaries is a high-pressure system.
- Torsion can cause venous drainage to stop, whereas arterial supply into the ovary remains unchanged. This causes congestion and swelling of the ovary but prevents immediate infarction.
- More than half of all torsions occur on the right side, likely because the right utero-ovarian ligament is longer than the left, and the sigmoid colon on the left side decreases the space for movement and torsion of the left ovary (2).
- Any increase in ovarian mass including cysts/neoplasms (benign > malignant), PCOS, ovarian stimulation, history of prior adnexal torsion, prior tubal ligation (1,3)
- Diagnosis and treatment of ovarian masses can decrease the rate of torsion. Awareness of the risk of torsion is important for patients undergoing ovarian stimulation for IVF treatments and for patients with known ovarian masses.
- Certain surgical techniques (such as cystectomy and ovariopexy) used during intervention for ovarian torsion may decrease the risk of future torsion, but these treatments remain controversial.
- Pregnancy is a risk factor for torsion (odds ratio, 18:1); however, it remains an uncommon event (0.167%). Rates of torsion have been cited at between 0.6% and 6% in pregnancies obtained by ovarian stimulation, and the rate of torsion increases to between 7.5% and 16% in patients presenting with ovarian hyperstimulation syndrome (1).
- The majority of cases in pregnancy occur in the 1st trimester.
- Reoccurrence is not uncommon, occurring in 19.5% of pregnant patients with torsion.
- Most commonly, functional ovarian cysts are the causative etiology of ovarian torsion (4).
- Laparoscopic treatment of the torsion is considered safe in pregnancy, with studies reporting between 2% and 5% risk of loss of the pregnancy following surgery and an 8% rate of preterm labor (5).
- Approximately 30% of cases of ovarian torsion are in women <20 years, and ∼15% of cases of ovarian torsion occur during infancy and childhood (3).
- Symptoms of ovarian torsion in the pediatric population are similar to those in adults, including abdominal pain, nausea and vomiting, and peritoneal signs (4).
- The most common pathologic findings in pediatric patients are benign cystic teratomas or paraovarian cysts (4).
- Rate of malignancy among torsed ovaries in children is rare, from 0% to 1.8% (5).
Commonly Associated Conditions
Pregnancy and ovarian stimulation
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