Clinical meaning
Ovarian torsion occurs when the ovary (and often the ipsilateral fallopian tube) rotates on its vascular pedicle -- the infundibulopelvic ligament (containing the ovarian artery and vein) and the utero-ovarian ligament -- partially or completely occluding its blood supply. The pathophysiology follows a predictable ischemic cascade. Initial rotation typically compresses the thin-walled, low-pressure ovarian vein and lymphatics first, while the higher-pressure ovarian artery continues to deliver blood. This creates massive venous and lymphatic congestion, causing the ovary to swell rapidly with edematous, hemorrhagic fluid. The enlarging, congested ovary becomes heavier, which can worsen the torsion degree. Eventually, arterial inflow is also compromised, leading to complete ischemia and if untreated, hemorrhagic infarction and necrosis. The dual blood supply to the ovary (from both the ovarian artery originating from the aorta and the ovarian branch of the uterine artery) explains a critical diagnostic limitation: Doppler ultrasound may demonstrate preserved arterial flow even with significant torsion, as collateral blood supply through the uterine artery branch can maintain some perfusion. This is why Doppler sensitivity for torsion is only 60-70%, and a normal Doppler does NOT rule out torsion. Ovarian torsion requires a lead point in most cases -- a mass or cyst greater than 5 cm that increases ovarian weight and mobility, acting as a fulcrum around which the pedicle twists. Dermoid cysts (mature cystic teratomas) and cystadenomas are the most common masses associated with torsion. Ovarian hyperstimulation from fertility treatments creates massively enlarged ovaries (8-12 cm) that are highly susceptible. Right-sided torsion is more common than left because the sigmoid colon limits adnexal mobility on the left side. The clinical significance of early surgical intervention cannot be overstated: laparoscopic detorsion within 6 hours of symptom onset preserves ovarian function in over 90% of cases, even when the ovary appears dusky or cyanotic at surgery. Reperfusion after detorsion restores viability in the vast majority of cases.