Ovarian Torsion
Definition
Ovarian torsion (aka adnexal torsion) refers to the twisting of the ovary around its supporting ligaments, causing compromised blood supply to the ovaries +/- fallopian tube
Aetiology
Most important risk factor: presence of an ovarian mass / cyst [Ref1][Ref2]
- >5cm poses a significant risk
- Dermoid cysts (mature cystic teratoma) are strongly associated with torsion
Other risk factors: [Ref1][Ref2]
- Young age
- Pregnancy (due to increased ovarian size and mobility)
- Hormonal stimulation (e.g. during fertility treatment)
- Presence of tubal / paratubal pathology (e.g. paratubal cysts, hydrosalpinx)
- Anatomical variations increasing adnexal mobility
Clinical Features
Typically presents as a sudden onset of severe unilateral lower abdominal and/or pelvic pain [Ref]
Other features: [Ref]
- Nausea and vomiting
- Abdominal / adnexal tenderness
- Lower abdominal fullness / palpable adnexal mass (if an ovarian mass / cyst is present)
Complications
The key complication is ovarian infarction and necrosis (→ loss of ovarian function and infertility)
The ovary is more resilient to vascular injury, a sharp decrease in function is typically observed after ~72 hours and necrosis is rarely seen before 24 hours of persistent torsion.
This is because of the ovary’s dual blood supply (ovarian and uterine arteries). In contrast, testicular torsion typically leads to irreversible ischaemic injury with permanent damage after 4-8 hours of symptom onset.
Investigation and Diagnosis
If ovarian torsion is suspected, the first and most important step is to exclude ectopic pregnancy using a urine pregnancy test.
Remember, every woman of reproductive age presenting with abdominal or pelvic pain should have a pregnancy test to rule out ectopic pregnancy.
1st line test: combined trans-abdominal and trans-vaginal ultrasound [Ref]
- Key findings:
- Enlarged oedematous ovary (→ asymmetric ovaries) with peripherally displaced ovarian follicles (sometimes described as a “string of pearls“)
- Whirlpool sign
- Free pelvic fluid (reflecting venous congestion/haemorrhage)
- Doppler may show reduced blood flow, however presence of arterial flow does NOT exclude torsion (up to 60% cases of confirmed torsion have preserved blood flow due to intermittent torsion or collateral circulation)
Definitive test: diagnostic laparoscopy
Management
ALL patients: prompt surgical intervention with diagnostic laparoscopy [Ref]
- Detorsion of the affected ovaries
- Preservation of the ovarian and tubal structures regardless of their intraoperative appearance (as ovarian function may recover even after prolonged torsion and gross discolouration)
- Intra-operative oophorectomy should only be performed if the ovary is non-viable and falls apart during surgery
Consider adjunct procedures: [Ref]
- Cystectomy / drainage of benign cysts
- Oophoropexy may be considered in selected cases with recurrent torsion / in paediatric patients
- Evidence of routine oophoropexy after a single episode of torsion is limited