OVARIAN TORSION

Ovarian torsion refers to the twisting of the ovary on its ligamentous supports, often resulting in impedance of its blood supply. It is the fifth most common gynecologic emergency and affects females of all ages. Expedient diagnosis is important to preserve ovarian function and prevent adverse sequelae. However, the diagnosis can be challenging because the symptoms are relatively nonspecific.

ETIOLOGY 

Ovarian torsion has been attributed to a variety of etiologies. Certain of these are more likely in particular age groups, but the anatomic changes that predispose to torsion can occur at all ages.

A large series of patients with surgically confirmed torsion reported that cysts and neoplasms accounted for 94 percent of cases (cysts 48 percent, neoplasms 46 percent), with the remainder occurring in the setting of normal appearing ovaries . Histopathology was benign in over 90 percent . While anatomic factors usually account for ovarian torsion in adults, normal ovaries have been demonstrated in over 50 percent of ovarian torsion in children under the age of 15. Thus, it should be recognized that children have a higher risk than adults of torsing normal ovaries.

Cysts and neoplasms predispose the ovary to swing on its vascular pedicle more readily. Larger masses are generally associated with greater potential for torsion until the size is so great that movement is impeded. In a series of 97 patients with torsion, 83 percent of torsed ovaries were 5 cm or larger. However, no specific threshold exists at which the size of the ovary precludes any risk of torsion. The size of the ovary in relation to the pelvis may also play a role (ie, the size of the pelvis varies across different women).

In adults, torsion has also been described following laparoscopic hysterectomy suggesting even releasing the fulcrum on which ovaries usually can twist is not protective for torsion ..

Diagnostic sonography should be the first examination performed; typically, the affected ovary is enlarged, with multiple immature or small follicles along its periphery. Color Doppler sonography can help in determining whether blood flow is impaired. Rarely, computed tomography (CT) or magnetic resonance imaging (MRI) is needed to make a definitive diagnosis. CT or MRI can serve as a secondary modality when ultrasonographic findings are nondiagnostic.