Management of Adnexal Torsion

Marjan Attaran

General Principles

Definition

Adnexal torsion is defined as twisting of the ovary and/or tube around usually the utero-ovarian ligament and in case of the ovary the infundibulopelvic ligament (Fig. 11.4.1). It is responsible for 2.7% of all gynecologic emergencies. This number is likely an underestimate given that some patients fail to undergo surgery and thus a definitive diagnosis is not made. Patients typically present with sudden-onset lower abdominal pain that may be continuous or intermittent. The exact cause of adnexal torsion is not known. However, not uncommonly an adnexal mass such as an ovarian cyst, a hydrosalpinx, or a paraovarian cyst is present. In some instances, it is believed that an unusually long utero-ovarian ligament may lend itself to torsion. This diagnosis is usually made in reproductive-aged women, although it is not uncommon in premenarchal girls.
As a result of the twisting about the gonadal vessels, venous flow is first compromised and thus the ovary becomes edematous. Once arterial flow is compromised, the ovary and tube will experience ischemia and possible necrosis.
The classic signs of ovarian torsion are acute abdominal/pelvic pain accompanied by an adnexal mass and signs of peritoneal irritation. Other symptoms may include nausea and fever, although the latter may occur much later.
The right side is most frequently affected by torsion possibly secondary to the fact that the sigmoid traverses to the left and reduces space for torsion to occur.

Differential Diagnosis

The preoperative accuracy of adnexal torsion is at best 44% as noted in a study by Cohen,¹ where by only 29 out of 66 patients who underwent laparoscopy for presumed diagnosis of torsion in fact had adnexal torsion. Other causes of lower abdominal pain must be considered in the differential diagnosis. These include:
- Ruptured ovarian cyst
- Appendicitis
- Pelvic inflammatory disease
- Ectopic pregnancy
- Colitis
- Pyelonephritis
- Nephrolithiasis
- Degeneration of a fibroid

Figure 11.4.1. Ovary and tube twisted upon the utero-ovarian ligament.

Anatomic Considerations

In most cases of torsion an ovarian tumor is present. Cysts less than 5 cm are less likely to lead to torsion than larger cysts.
In conditions where pelvic adhesions are likely, such as endometriosis and past pelvic inflammatory disease, there is less of a likelihood of torsion. However, hydrosalpingies may lead to an isolated twisting of the fallopian tube.
Benign ovarian cysts are more likely to lead to ovarian torsion than malignant lesions, since malignant lesions can invade adjacent tissues thereby prohibiting movement and torsion.
During early pregnancy as the uterus is growing the corpus luteum may twist upon itself.
Ovarian torsion has also been described in patients with congenital anomalies such as elongated utero-ovarian ligament or abnormally located ovary due to müllerian agenesis.
Patients undergoing ovarian stimulation are at increased risk for ovarian torsion secondary to the enlarged size of the ovaries. The diagnosis in this case is extremely difficult given the multicystic appearance of the ovaries bilaterally.

Imaging and Other Diagnostics

Pelvic ultrasound is usually the first imaging tool utilized to assist with this diagnosis (Fig. 11.4.2).

Figure 11.4.2. Transvaginal ultrasound image of torsed ovary.

Figure 11.4.3. Swollen large right ovary.
A transvaginal approach will provide better visualization of the ovarian vessels compared to the transabdominal approach.
Indirect findings can include an enlarged ovarian/adnexal mass, multiple cystic structures in the periphery of the enlarged ovary, thickening of interfollicular tissue, and some fluid in the cul-de-sac or adjacent to the enlarged adnexa. The location of the ovary may also be abnormal. It may be located anterior to the uterus or on the contralateral side.
The only direct ultrasound sign of torsion is the “whirlpool sign.”²
Doppler flow studies are routinely used to demonstrate flow in the ovaries. Doppler studies can miss torsion in 60% of cases but its positive predictive value is 100%. Thus while establishing the existence of flow to the ovaries may be reassuring; the clinical picture should direct the course of action. Lack of flow may be a late symptom of torsion, when not only venous but arterial flow is compromised.
Given that the patient commonly presents to the emergency room with such symptoms the CT scan may be the first imaging study performed. Findings will include enlarged adnexa, fallopian tube thickening, ascites, and uterine deviation to the twisted side.
MR findings on T2-weighted images include swollen ovarian stroma (the hyperintensity of the ovarian stroma is similar to that of water) (Fig. 11.4.3).