Ovarian torsion is the twisting of an ovary around the adnexal ligaments. It most commonly occurs in women of childbearing age. Risk factors include ovarian enlargement (e.g., ovarian cysts, tumors, or hyperstimulation syndrome), laxity of pelvic ligaments, a history of pelvic inflammatory disease, and previous pelvic surgery. Torsion can lead to venous congestion and edema, which cuts off the blood supply to the ovary. Patients present with sudden onset unilateral lower abdominal or pelvic pain, and there may be a palpable adnexal mass and adnexal tenderness. In partial ovarian torsion, the pain may be intermittent or resolve spontaneously. Diagnosis is made using pelvic ultrasound. Torsion is a surgical emergency and exploratory laparoscopy is indicated in all patients with suspected ovarian torsion. Delays in treatment may result in ovarian necrosis and infertility.
- Ovarian enlargement is the most important risk factor; common causes include:
- Long ovarian ligaments and laxity of pelvic ligaments (e.g., suspensory ligament) may be predisposing factors, especially in adolescents. 
- Strenuous physical activity 
- History of pelvic inflammatory disease
- Previous pelvic surgery, e.g., tubal ligation or hysterectomy 
- Twisting of the ovary and the fallopian tube around the infundibulopelvic ligament and ovarian ligament → compression of the ovarian veins and lymphatics → ↓ venous and lymphatic outflow → edema of the fallopian tube and ovary
- Worsening edema of the fallopian tube → compression of the ovarian artery → ovarian ischemia and necrosis
- Friable necrotic ovarian tissue → hemorrhage
- Most common during reproductive years but can occur at any age 
- Sudden-onset unilateral lower abdominal and/or pelvic pain
- Nausea and vomiting
- Adnexal mass may be palpable
- Adnexal tenderness
- In partial ovarian torsion, abdominal pain may be intermittent or resolve spontaneously.
Pain due to ovarian torsion may resolve intermittently as a result of spontaneous detorsion.
- Pelvic ultrasound with Doppler: imaging modality of choice 
MRI abdomen and pelvis with contrast 
- Indication: inconclusive findings on ultrasound
- Supportive findings
- CT abdomen and pelvis with IV contrast: not routinely recommended 
Consult gynecology immediately if ovarian torsion is clinically suspected, even if ultrasound findings are normal. 
Ovarian torsion is a frequently missed diagnosis; a delay in treatment may affect fertility and pose a medicolegal risk. 
Emergency exploratory laparoscopy: indicated in all patients with suspected ovarian torsion
- Premenopausal women: adnexal detorsion and preservation of ovarian function
- Postmenopausal women: salpingo-oophorectomy 
- Additional procedures: based on intraoperative findings
- Ovarian cystectomy or drainage: in patients with ovarian cysts
- Oophoropexy: utero-ovarian ligaments are plicated or the ovary is fixed to either the posterior abdominal or pelvic sidewall to decrease the risk of retorsion.
- Supportive care
- Postoperative follow-up
- Prognosis: Viability may be preserved in ∼ 90% of cases even if there is intraoperative evidence of ovarian ischemia. 
Diagnostic laparoscopy should be performed if there is strong clinical suspicion for ovarian torsion despite inconclusive imaging findings.