Ovarian and fallopian tube torsion

INTRODUCTION — Ovarian torsion refers to the complete or partial rotation of the ovary on its ligamentous supports, often resulting in partial or complete obstruction of its blood supply. It is one of the most common gynecologic surgical emergencies and may affect females of all ages [1]. The fallopian tube often twists along with the ovary; when this occurs, it is referred to as adnexal torsion. Isolated torsion of the fallopian tube is less common, and torsion of paratubal, broad ligament, and paraovarian cysts may also occur.

Prompt diagnosis is important to preserve ovarian and/or tubal function and to prevent other associated morbidity. However, making the diagnosis can be challenging because the symptoms are relatively nonspecific.

This topic will focus mainly on ovarian torsion in nonpregnant adult patients, but ovarian torsion in other populations (fetuses, pediatric, and pregnant patients) will also be reviewed. An overview of the approach to an adnexal mass and to acute pelvic pain is presented separately. (See "Approach to the patient with an adnexal mass" and "Acute pelvic pain in nonpregnant adult females: Evaluation".)

PATHOPHYSIOLOGY — The ovary is suspended by the infundibulopelvic ligament (also referred to as the suspensory ligament of the ovary), is not fixed, and may be positioned lateral and/or posterior to the uterus, depending on the position of the patient (figure 1). When torsion occurs, the ovary typically rotates around both the infundibulopelvic ligament and the utero-ovarian ligament. Rotation of the infundibulopelvic ligament causes compression of the ovarian vessels and compromises lymphatic and venous outflow and arterial inflow.

Numerous variables (eg, number of twists of the blood vessels, tightness of the twists) affect the flow into and out of the ovary. The arterial supply to the ovary is not initially interrupted to the same degree as the venous drainage since the muscular arteries are less compressible than the thin walls of the veins.

Continued arterial perfusion in the setting of blocked outflow leads to ovarian edema with marked ovarian enlargement and further vascular compression. Ovarian ischemia then occurs and can result in ovarian necrosis and local hemorrhage.

The right ovary appears to be more likely to undergo torsion compared with the left, possibly because the right utero-ovarian ligament is longer than the left and/or the presence of the sigmoid colon in the left pelvis may help to prevent torsion on that side [2,3].

NATURAL HISTORY — Chronic adnexal torsion with complete occlusion of the ovarian blood supply will ultimately result in necrosis of the torsed tissues and loss of ovarian function [4]. The necrotic tissue may autoamputate or involute over time; pelvic adhesions may also form, and this can result in pelvic pain or tubal infertility (if the remaining ovary is functional). Additional potential adverse outcomes include hemorrhage and peritonitis [5-8], although hemorrhage requiring blood transfusion and sepsis are rare [9-13].

There is no specific duration of time after symptom onset that is predictive of certain ovarian necrosis [14,15]. In one observational study of 22 pediatric patients with ovarian torsion, the 6 patients with salvaged ovaries had a mean time from symptom onset to surgical evaluation of 87 hours (range 7 to 159) [14].

Some patients may have intermittent adnexal torsion, which is associated with few, if any, adverse consequences as perfusion is not persistently compromised.

Bilateral asynchronous torsion is rare [16,17].

EPIDEMIOLOGY — The incidence of adnexal torsion is unknown. There are some data regarding the rate of torsion among patients presenting for gynecologic care to an acute care setting. In a classic report of a 10-year review of patients at a women's hospital, ovarian torsion accounted for 2.7 percent of emergency surgeries [18]. Torsion was the fifth most common surgical emergency, preceded by (in descending order) ectopic pregnancy, corpus luteum rupture with hemorrhage, pelvic inflammatory disease, and appendicitis. In a 10-year review of surgically treated adnexal masses, torsion accounted for 15 percent of cases [19].

Ovarian torsion may occur in females of all ages, even fetuses and neonates, particularly if an ovarian mass is present [20-22] (see 'Fetuses' below and 'Pediatric patients' below and 'Risk factors' below). The majority of cases occur in patients of reproductive age [23-25]. In 10- to 15-year retrospective series at single institutions, the mean age of patients with torsion was between 29.0 and 33.5 years [24-26].

The incidence of ovarian torsion in fetuses, pediatric, and pregnant patients is discussed in detail below. (See 'Adnexal torsion in other populations' below.)

RISK FACTORS — Risk factors for ovarian torsion include the presence of a mobile ovarian mass and a history of prior ovarian torsion. However, it is important to note that normal ovaries can undergo torsion [27]. (See 'Clinical presentation' below and 'Pediatric patients' below.)

Some data suggest that tubal ligation is associated with an increased risk of ovarian torsion, but the degree of this risk is uncertain [24,26].

Ovarian mass — In adults, the most common predisposing factors of ovarian torsion are an ovarian physiologic cyst (functional cyst, corpus luteum) or benign neoplasm (table 1). The presence of an ovarian mass predisposes the ovary to rotate on the axis of the infundibulopelvic and utero-ovarian ligaments and become fixed in a torsed position. Over 85 percent of patients with ovarian torsion have an ovarian mass [20,23,24,28]. Many of these masses are associated with the reproductive cycle or reproductive hormones (eg, corpus luteum, ovulation induction); therefore, the risk of torsion is increased during pregnancy, in women of reproductive age, with polycystic ovarian syndrome [29,30], or undergoing ovulation induction for treatment of infertility [25].

Characteristics of an ovarian mass that may affect the risk of torsion include:

●Large size, which increases the risk of torsion. Torsion is most likely to occur when the ovary is 5 cm in diameter or larger [20,23,24]. This represents an average, and torsion may occur with an ovary of any size; in general, as the size of the ovary increases, the risk of torsion increases. Although it has been postulated that very large ovaries are less likely to undergo torsion because the size impedes movement within the pelvis, the upper limit of size has not been defined. The wide range of sizes of ovarian masses in patients with torsion was illustrated in a series in which ovarian size ranged from 1 to 30 cm (mean 9.5 cm) in the 87 cases [24].

Ovulation induction for treatment of infertility can result in the formation of large ovarian follicular cysts and, in some patients, massive ovarian enlargement due to hyperstimulation. Among patients with ovarian hyperstimulation syndrome, the incidence of torsion was 8 and 12 percent in two series [25,31]. (See "Overview of ovulation induction".)

●Fixation, which decreases the risk of torsion. Ovaries that are fixed in the pelvis (eg, endometrioma, tubo-ovarian abscess, malignancy) are less likely to undergo torsion than nonfixed ovaries. The rate of malignancy in torsed ovaries is <3 percent overall [20,25,26]; the rate is higher in postmenopausal patients (3 to 20 percent) in whom the baseline risk of ovarian malignancy is higher than in premenopausal patients [32-37]. (See 'Other patients: Salpingo-oophorectomy' below.)

Prior ovarian torsion — Patients with prior ovarian torsion appear to be at increased risk for recurrence, but the rate of recurrence is unclear. In one series, 23 of 216 cases (11 percent) of torsion were recurrent [26]. It should be noted that recurrent torsion can occur in the same "salvaged ovary" or can occur in the other ovary (ie, asynchronous bilateral ovarian torsion) [2].

Patients with normal ovaries may be at higher risk of recurrent torsion than those with abnormal ovaries, but data are very limited. In one retrospective study, torsion recurred in 7 of 11 patients (64 percent; mean age 25 years) with normal adnexa compared with 4 of 46 patients (9 percent; mean age 31 years) with abnormal adnexa; all patients with recurrent torsion had the same diagnosis (torsion with a normal versus abnormal ovary) for the first and second torsion events [28].

CLINICAL PRESENTATION — The classic presentation of ovarian torsion is the acute onset of moderate to severe pelvic pain, which may be diffuse or localized to one side, often with nausea and vomiting, in a patient with an adnexal mass [5,20,38,39]. A history of recent vigorous activity or a sudden increase in abdominal pressure may be an inciting event and should raise suspicion for this diagnosis [40-42].

However, presentation may vary, and these symptoms are also associated with other conditions. In addition, torsion may occur in the absence of an adnexal mass, especially in premenarchal patients. Thus, a high index of suspicion is required to make the diagnosis. This is of particular importance if torsion results in the loss of ovarian function since bilateral asynchronous adnexal torsion, which is rare, can occur. (See 'Pediatric patients' below and 'Differential diagnosis' below and 'Risk factors' above.)

The frequency of presenting symptoms and findings of ovarian torsion were as follows in series evaluating 50 or more patients [24-26,43]:

●Pelvic pain (90 percent) – Pelvic pain is often of sudden onset and usually moderate to severe [24,25,34]. The character of the pain may be sharp, dull, stabbing, colicky, or crampy, and it may radiate to the flank, back, or groin. Most patients present for evaluation within one to three days of the onset of the pain; however, there are rare reports of torsion associated with pelvic pain that was present for up to 210 days, which may represent cases of intermittent torsion [44].

●Ovarian mass (86 to 95 percent) – (See 'Ovarian mass' above.)

●Nausea with or without vomiting (47 to 70 percent) – In our experience, the onset of nausea typically coincides with the onset of pelvic pain.

●Fever (2 to 20 percent) – Fever is typically low grade and may be a marker of adnexal necrosis, particularly in the setting of leukocytosis. (See 'Laboratory findings' below.)

CLINICAL FINDINGS

Physical examination — Findings on physical examination are variable:

●Most patients exhibit pelvic and/or abdominal tenderness, although tenderness on examination is absent in as many as one-third of patients [24-26]. Tenderness may be localized to the side of an adnexal mass, if present, or may be diffuse.

●A palpable pelvic mass may or may not be present.

●Peritoneal signs are present in a small number of patients and should raise concern for adnexal necrosis.

●A low-grade fever may be present. (See 'Clinical presentation' above.)

Laboratory findings — Laboratory abnormalities are absent in many patients. In rare cases, hemorrhage from a torsed ruptured corpus luteal cyst may result in anemia, and adnexal necrosis may lead to infection with associated leukocytosis. If these laboratory findings are present in a patient with suspected torsion, they raise concern for severe adnexal damage.

While there may be an association between elevated serum interleukin 6 (IL-6) levels and ovarian torsion [45,46], this is a nonspecific marker of inflammation, and we do not obtain this test in our practice.

Imaging studies

Ultrasound — Sonographic findings (image 1 and image 2) vary [47-49]:

●The ovary may be rounded, enlarged, and have a heterogenous appearance compared with the contralateral ovary, due to edema, engorgement, and/or hemorrhage.

●The ovary may be located anterior to the uterus, rather than in the normal location lateral or posterior to the uterus; location may change depending on the degree of bladder filling.

●Multiple small follicles (ie, "string of pearls," "peripheralization of the follicles") may be present peripherally due to displacement by edema. In one retrospective review of ultrasound evaluation in patients with adnexal torsion (median age 30 years), ovarian stromal edema with or without peripherally displaced follicles was visualized in 201/254 (79 percent) of patients with torsion [49].

This feature is also seen in polycystic ovary syndrome (PCOS), although in polycystic ovaries, the stroma is echogenic centrally, the ovary does not appear edematous, and the patient does not have acute pain; in PCOS, the ovaries are also typically similar (in size and appearance) bilaterally.

●An ovarian or tubal cyst/mass may be present. Scanning with the vaginal probe in the region of the mass will often elicit pain.

●Doppler flow:

•Doppler flow within a torsed ovary may be present (normal), decreased, or absent [6,50-55]. Normal Doppler flow does not exclude the diagnosis of torsion since preservation of flow can be attributed to incomplete occlusion, intermittent torsion, and collateral blood supply (eg, utero-ovarian vessels, infundibulopelvic vessels) [50]. Doppler flow of the contralateral (normal) ovary should also be assessed for comparison and to ensure proper flow settings [6].

In one prospective study including 28 patients with ovarian torsion and a visibly twisted pedicle, Doppler ultrasound demonstrated normal flow in 16 patients (57 percent) and absent or impaired flow in 12 patients (43 percent) [54]. All patients with absent or impaired flow were found to have necrotic ovaries at the time of surgery.

However, other studies show varying results; in two small cohort studies, absent or impaired ovarian venous flow on Doppler ultrasound had a sensitivity and specificity for a diagnosis of ovarian torsion between 43 and 100 percent and 92 and 97 percent, respectively [56,57].

•The ovarian vessels may display the "whirlpool sign," a round hyperechoic structure with concentric hypoechoic stripes or a tubular structure with internal heterogeneous echoes. It is thought to represent the twisting of the vascular pedicle. In the retrospective review of ultrasound evaluation in patients with adnexal torsion discussed above, the "whirlpool sign" was visualized in 139/153 (91 percent) patients with torsion [49]. Two smaller series found this sign to have a sensitivity of 90 percent or higher for the diagnosis of torsion [58,59].

The reported sensitivity of ultrasound for the diagnosis of ovarian torsion ranges from 46 to 75 percent [48,60]. In one series of 63 patients with suspected torsion, the most sensitive sonographic findings were ovarian edema (sensitivity 85.1 percent and specificity 18.8 percent), abnormal ovarian blood flow (85.1 and 37.5 percent), and relative enlargement of ipsilateral ovary (85.1 and 18.8 percent) [60]. A specificity of 100 percent was achieved by combining two or more findings, although the highest sensitivity was approximately 55 percent when two or more findings were combined.

Other imaging studies — Pelvic magnetic resonance imaging and computed tomography scan are not routinely ordered for evaluation of adnexal torsion. If these studies are performed initially, findings will be similar to that of ultrasound and may include an enlarged, edematous ovary in an abnormal location and, with contrast enhancement, coiled ovarian vessels demonstrating the "whirlpool" sign [61-66], and additional imaging with ultrasound may be unnecessary [67].

DIAGNOSTIC EVALUATION — Imaging of the pelvis, preferably with pelvic ultrasound, is the mainstay of evaluation in patients in whom ovarian torsion is suspected. Human chorionic gonadotropin and a complete blood count are also obtained to aid in the differential diagnosis. (See 'Clinical findings' above and 'Imaging studies' above and 'Differential diagnosis' below.)

DIFFERENTIAL DIAGNOSIS — The differential diagnosis of ovarian torsion includes other conditions that present with acute pelvic pain and/or an adnexal mass and include ectopic pregnancy, ruptured ovarian cyst, tubo-ovarian abscess, and appendicitis.

●Ectopic pregnancy – In a patient with adnexal pain with/without an adnexal mass, a negative serum human chorionic gonadotropin excludes ectopic pregnancy. (See "Ectopic pregnancy: Clinical manifestations and diagnosis".)

●Ruptured ovarian cyst – Pelvic pain due to cyst rupture is often at midcycle, in contrast to torsion where pain is not more common at a specific time of the menstrual cycle. Similar to torsion, a history of recent vigorous activity (including vaginal intercourse) may be an inciting event. Both conditions can be accompanied by sonographic evidence of hematoperitoneum or free fluid in the pelvis [48], but the appearance of a torsed ovary is generally different from a ruptured ovarian cyst. (See "Evaluation and management of ruptured ovarian cyst".)

●Tubo-ovarian abscess – Tubo-ovarian abscess is more likely to have an indolent course and be associated with fever than torsion, and the characteristic sonographic appearance of an abscess is a complex, multilocular mass, which is not usually found in torsion. (See "Epidemiology, clinical manifestations, and diagnosis of tubo-ovarian abscess", section on 'Evaluation of patients with suspected TOA'.)

●Appendicitis – Appendicitis can sometimes be differentiated from torsion by the patient's symptoms (eg, anorexia, periumbilical pain with subsequent migration to the right lower quadrant), physical examination to localize the pain, and by the presence of characteristic findings on imaging (computed tomography being the preferred imaging modality) [68,69]. Use of biomarkers (eg, CD64) have been proposed to differentiate between these two clinical entities, but they are not typically performed [70]. (See "Acute appendicitis in adults: Clinical manifestations and differential diagnosis" and "Acute appendicitis in adults: Diagnostic evaluation".)

The differential diagnosis also includes other conditions, including an ovarian cyst or neoplasm that is not torsed, endometriosis, or a degenerating leiomyoma. (See "Acute pelvic pain in nonpregnant adult females: Evaluation" and "Chronic pelvic pain in nonpregnant adult females: Causes".)

DIAGNOSIS — A definitive diagnosis of ovarian torsion is made by direct visualization of a rotated ovary at the time of surgical evaluation. (See 'Surgical evaluation' below.)

A presumptive diagnosis of torsion can be made with a fair degree of confidence in the presence of acute pelvic pain; imaging demonstrating an adnexal mass with an appearance consistent with torsion (particularly if pain is elicited when scanning over the adnexa with a vaginal ultrasound probe); and after exclusion of ectopic pregnancy, tubo-ovarian abscess, and appendicitis. Additional findings, such as nausea, fever, and pelvic tenderness on examination, further support the diagnosis. (See 'Clinical presentation' above and 'Ultrasound' above and 'Differential diagnosis' above.)

The difficulty in diagnosis was illustrated in a series of 115 cases of adnexal torsion that revealed that the correct preoperative diagnosis was made in only 38 percent of patients [71].

SURGICAL EVALUATION — The goal of surgical evaluation is to confirm torsion and assess ovarian viability.

●A laparoscopic approach is typically used, and most surgeons document the findings with photographs of the adnexa. Surgical evaluation should be performed by a gynecologist or a general surgeon experienced with detorsion and preservation of the ovary. (See "Approach to the patient with an adnexal mass", section on 'Scope of surgery'.)

●A torsed ovary should be considered potentially viable as ovarian necrosis is rare; the vast majority of torsed ovaries can and should be salvaged (unless malignancy is suspected). However, there is no highly effective intraoperative approach to determining ovarian viability in patients with ovarian torsion.

•An ovary that is dark and enlarged, with or without hemorrhagic lesions, is most likely still viable; this appearance is often due to vascular and lymphatic congestion and not necrosis (picture 1 and picture 2). It is our view that it is best to attempt to preserve the tube and ovary with acknowledgment that sometimes the tube and ovary will not survive and will either involute or need to be removed at a later date.

Traditionally, ovaries with this appearance have been thought to be nonviable, but multiple studies have found that many patients (even those with an ovary that is blue or black) retain ovarian function following detorsion [15,72-79]. In studies with ultrasound follow-up, the rate of follicular development after detorsion was 80 percent or higher [65,76,78,79]. Serum anti-Müllerian hormone levels may also be higher in patients with a history of ovarian torsion managed with detorsion compared with unilateral oophorectomy (5.5 ± 2.3 ng/mL versus 2.7 ± 2.1 ng/mL; one study) [80]. A possible explanation of the viability of ovarian tissue, based on rat data, is that total arterial occlusion may not be present in the torsed ovary despite venous and lymphatic congestion [81].

•Rarely, ovarian or tubal necrosis is present at the time of surgery. The appearance on gross inspection of a necrotic ovary or tube includes a gelatinous or poorly defined structure that "falls apart" when manipulated.

•Other approaches have been proposed to assess whether ovarian perfusion is present. One technique is ovarian bivalving, in which the ovary is untwisted and the ovarian cortex incised [82]; we use this technique in cases of enlarged edematous ovaries that do not contain a cyst on ultrasound. In our practice, we make the incision using a laparoscopic instrument with an electrosurgical "L-hook" needle tip attachment. This method allows visualization of whether blood flow is present at the incision. In addition, there is a potential therapeutic effect by relieving the increased pressure exerted by the lymphatic and venous congestion (picture 3) [82,83].

Another approach that has been reported is intraoperative intravenous fluorescein injection followed by direct visualization of the affected ovary under ultraviolet light [84]. However, this approach requires specialized equipment, and its efficacy has not been validated.

MANAGEMENT — (algorithm 1)

Premenopausal patients with a viable, nonmalignant ovary: Detorsion — The mainstay of treatment of ovarian torsion in premenopausal patients is swift operative detorsion to preserve ovarian function, when possible [73-77].

●Torsed ovaries can and should be salvaged whenever possible and resection reserved for those patients in whom malignancy is suspected. (See 'Surgical evaluation' above and 'Other patients: Salpingo-oophorectomy' below.)

●Detorsion consists of untwisting the torsed ovary and any other torsed structure. During laparoscopy, this can be accomplished with a blunt probe or an atraumatic grasper. If laparotomy is performed, the ovary can be untwisted manually.

●Cystectomy is often performed in addition to detorsion if a benign mass is present. If cystectomy cannot be performed because of surrounding edema and concern that dissection may further compromise vascular perfusion, the cyst can be drained and cystectomy performed at a later date. This concept (ie, a two-staged procedure) provides time for edema to decrease and reperfusion to occur, thereby facilitating dissection of the ovarian cyst wall from the normal ovarian cortex.

As discussed above, continued ovarian function after detorsion is likely (see 'Surgical evaluation' above). Historically, it was believed that conserving the ovary could lead to adverse effects (eg, hemorrhage, peritonitis from the necrotic tissue, adhesion formation) and restoring normal anatomy via detorsion could dislodge a clot in the ovarian vein and result in an embolus [85]. However, evidence supports that detorsion is not associated with these complications [8,86,87]. In a retrospective study of over 89,000 patients with ovarian torsion of whom 20,597 had conservative ovarian-preserving surgery, detorsion (with or without cyst drainage, cystectomy, and/or oophoropexy) compared with oophorectomy had similar risks of venous thromboembolism (0.2 versus 0.3 percent) and sepsis (0.4 versus 0.3 percent) and was associated with a lower risk of other perioperative complications (10 versus 13.6 percent, odds ratio 0.7, 95% CI 0.6-0.8) [87].

While the benefits of ovarian conservation appear to outweigh the theoretical risks, irreversible ischemic damage to the adnexa can occur and may lead to infection if a truly necrotic ovary is retained.

Postoperative care — Postoperative care and instructions following detorsion should include observation for signs of peritonitis or sepsis (fever, worsening abdominal pain, peritoneal signs, hemodynamic instability). This rare complication was reported in a pregnant patient who underwent laparotomy and detorsion of a hyperstimulated ovary with reperfusion of the torsed adnexa observed intraoperatively [13]. Reexploration because of peritonitis two days postoperatively revealed clear evidence of a necrotic ovary. (See 'Natural history' above.)

Other patients: Salpingo-oophorectomy — Salpingo-oophorectomy is indicated in the following clinical settings:

●Nonviable ovary – A nonviable ovary that is clearly necrotic/gelatinous with loss of all normal anatomic structures requires removal. (See 'Surgical evaluation' above.)

●Suspicion for malignancy – Salpingo-oophorectomy is required if ovarian or fallopian tube cancer is suspected.

Evaluation for malignancy typically depends, in part, on measurement of serum tumor markers and findings on serial pelvic sonography. These results are often not available for patients who require urgent surgery, so decisions regarding salpingo-oophorectomy should be made based on the available information and frozen section, if performed. The evaluation and management of an adnexal mass if malignancy is suspected are discussed in detail separately. (See "Approach to the patient with an adnexal mass", section on 'Patients at increased risk of malignancy' and "Adnexal mass: Ultrasound categorization".)

●Postmenopausal patients – Ovarian torsion is rare in postmenopausal patients, but when it occurs, removal of the affected ovary and tube is reasonable to prevent recurrence. In addition, if an ovarian mass is present, removal of the adnexa is the standard in this patient population due to the risk of malignancy. Bilateral salpingo-oophorectomy is only indicated if malignancy is suspected. (See 'Ovarian mass' above.)

Intraoperatively, the ovary should be detorsed to better visualize the mass and allow better delineation of the infundibulopelvic ligament and location of the ureter to avoid surgical complications. The ovary is then removed in the usual fashion (see "Oophorectomy and ovarian cystectomy").

PREVENTION OF RECURRENCE — The role of ovarian suppression with oral contraceptives or oophoropexy for the prevention of recurrent torsion events remains uncertain [28,88-91].

●Suppression of ovarian cysts – Low-dose estrogen-progestin contraceptives (formulations containing <50 mcg estrogen) can be used to suppress the formation of new ovarian cysts in postmenarchal patients without contraindications to a combination pill. While high-dose oral contraceptives (≥50 mcg estrogen) result in fewer ovulations and cysts than low-dose formulations [92-96], they are associated with increased thrombotic risk and are therefore not used. (See "Approach to the patient with an adnexal mass", section on 'Management according to mass type' and "Combined estrogen-progestin contraception: Side effects and health concerns".)

●Oophoropexy – Unilateral or bilateral oophoropexy following ovarian detorsion has also been used to prevent recurrence, although there are no high-quality data regarding the efficacy of this approach and long-term follow-up fertility studies have not been performed [97-100]. (See 'Fetuses' below.)

In our practice, we offer oophoropexy to patients who require, or have previously undergone, oophorectomy and thus have only one remaining ovary. Bilateral asynchronous ovarian torsion can occur, which could leave the patient agonadal. The oophoropexy can either be performed at the time of removal of the dead ovary or any time thereafter.

The procedure can be performed laparoscopically, and we typically shorten the utero-ovarian ligament; or, if the ovary is greatly enlarged without a discrete mass (at the time of the torsion event), then it can be sutured to the uterosacral ligament (picture 4) [101]. The procedure is similar to that of ovarian transposition prior to pelvic radiation, but in the case of oophoropexy following detorsion, the ovary does not require mobilization to a more cephalad position. This is discussed in detail elsewhere. (See "Ovarian transposition before pelvic radiation", section on 'Procedure'.)

SPECIAL CONSIDERATIONS

Adnexal torsion in other populations

Fetuses — Ovarian masses in a fetus are occasionally detected on prenatal ultrasound and are followed with serial sonography, and in utero ovarian torsion can occur. In a series of 66 fetuses with ovarian cysts followed with serial ultrasound examinations, 12 (18 percent) developed sonographic changes consistent with torsion while still in utero [22].

If torsion occurs, the ovary may undergo necrosis and develop into a calcified persistent mass or resorb. Prenatal puncture of ovarian cysts thought to be at risk for torsion has been described, but this is controversial [102]. Consultation with a maternal-fetal medicine specialist is advised. (See "Ovarian cysts in infants, children, and adolescents".)

Pediatric patients — Torsion accounts for 20 to 30 percent of ovarian surgeries in pediatric patients [20,103].

●Neonates and infants – In most instances, ovarian cysts in neonates and infants have already been visualized on a prenatal ultrasound and are being followed with serial sonography to track growth of the cyst or presence of hemorrhage [21] (see 'Fetuses' above). A series of 30 neonates with prenatally diagnosed ovarian cysts that persisted after birth found that 30 to 40 percent required surgical intervention due to torsion in the first weeks after birth [21]. The general evaluation and management of newborns and infants with ovarian cysts are discussed in detail separately. (See "Ovarian cysts in infants, children, and adolescents", section on 'Ovarian cysts in the fetus and neonate' and "Ovarian cysts in infants, children, and adolescents", section on 'Ovarian cysts in infants and prepubertal children'.)

If there is suspicion for torsion based on feeding intolerance, vomiting, abdominal distension, and fussiness/irritability as well as suggestive ultrasound findings, the patient should be evaluated surgically and managed in the same fashion as other patients [5,104-109]. A laparoscopic approach is appropriate if a surgeon with expertise in pediatric laparoscopy is available [110]. If a gynecologic pediatric surgeon is not available, an intraoperative consultation from a gynecologist should be obtained [111]. (See "Overview of laparoscopy in children and adolescents".)

●Premenarchal patients – As with postmenarchal patients, torsion in premenarchal patients can occur with or without an adnexal mass (see 'Clinical presentation' above). In children under the age of 15, normal ovaries have been demonstrated in 22 to 55 percent of patients with ovarian torsion [14,23,112]. One hypothesis is that the utero-ovarian ligament is normally elongated in the premenarchal girl, which facilitates ovarian torsion by permitting excessive ovarian movement, but this has not been proven. The utero-ovarian ligament shortens as girls mature through puberty [91,113,114]. Asynchronous bilateral torsion of normal ovaries has also been reported [115,116].

The clinical presentation in premenarchal patients may differ from other patients as they may be more likely to present with nausea and vomiting [117], and diffuse rather than localized pain. In a retrospective study (41 premenarchal patients, 208 postmenarchal patients), premenarchal patients were more likely to present with diffuse pain, fever, restlessness, and a palpable pelvic mass and had a longer duration of symptoms before presentation and treatment compared with postmenarchal patients [118]. They were also more likely to have a finding of a bluish black ovary at surgery (61 versus 41 percent).

As with postmenarchal patients, the mainstay of treatment of ovarian torsion in premenarchal patients is swift operative evaluation to preserve ovarian function. In our practice, we perform oophoropexy at the time of the detorsion procedure in premenarchal patients with a normal ovary as the rate of recurrence is higher in patients with a normal compared with abnormal ovary (see 'Prior ovarian torsion' above). We do not perform oophoropexy if torsion was caused by a cyst/mass and drainage (cyst) or excision (mass) was performed. Some other clinicians advise performing oophoropexy in every case of childhood torsion, especially if one ovary is removed [2,119], but others are concerned about the routine use of oophoropexy, since long-term follow-up fertility studies have not been performed [5].

The general evaluation and management of premenarchal patients with ovarian cysts are discussed in detail separately. (See "Ovarian cysts in infants, children, and adolescents", section on 'Ovarian cysts in infants and prepubertal children'.)

Pregnant patients — The incidence of torsion during pregnancy is uncertain with reports varying widely (image 3) [24-26,120]. In a series of 174 pregnant patients with a persistent adnexal mass ≥4 cm, the incidence of torsion was 15 percent [121]; torsion was most likely between 10 and 17 weeks of gestation but occurred through term and the postpartum period. Ovarian masses 6 to 8 cm in diameter were more likely to undergo torsion than larger masses, although torsion occurred in patients with masses that were 10 to 20 cm. Other series in pregnant patients with an adnexal mass have reported a much lower incidence of torsion (1 to 6 percent) [122,123].

Pregnant patients with torsion present similarly to nonpregnant patients [124] (see 'Clinical presentation' above and 'Clinical findings' above). Management is also similar but may be technically more difficult given the size of the gravid uterus. Reviews have confirmed the safety and effectiveness of laparoscopic management of torsion in pregnant patients; oophoropexy can also be performed [99,125-127]. (See "Laparoscopic surgery in pregnancy".)

As in nonpregnant patients, recurrence of torsion can occur. In one retrospective study, 7 of 41 pregnant patients with adnexal torsion who underwent detorsion had recurrent torsion in the same pregnancy [128].

Torsion of other adnexal structures

Isolated fallopian tube torsion — Torsion of the fallopian tube without ovarian torsion is a rare cause of lower abdominal pain in reproductive-age women (picture 5) [129-131]. Tubal torsion may occur either in the midportion of the tube itself or around the ligamentous supports of the tube. Ischemic or traumatic tubal injury caused by torsion, similar to injury resulting from infection or adhesive disease, may result in subfertility. Unrecognized tubal torsion will result in loss of tubal function and likely hydrosalpinx or necrosis with eventual resorption of the damaged tissue. (See "Female infertility: Causes", section on 'Fallopian tube abnormalities/pelvic adhesions'.)

Intermittent tubal torsion may occur and may have few, if any, adverse effects if perfusion is not persistently compromised and the tube is not damaged.

Possible risk factors for tubal torsion include tubal pathology (eg, hydrosalpinx, segmental tubal agenesis with resulting proximal hydrosalpinx, broad ligament cyst, paratubal cyst, neoplasm, tubal ligation device, ectopic pregnancy, congenital anomaly), ovarian mass, infection, altered tubal function (eg, abnormal peristalsis, spasm), or extrinsic lesions (eg, adhesions, endometriosis) [132,133]. In the largest retrospective review of patients with tubal torsion, 24 percent had normal-appearing tubes, 18 percent had hydrosalpinx, and 13 percent had infection; 12 percent of torsions were diagnosed during pregnancy [131].

The presenting symptoms and physical examination findings for tubal torsion are similar to those for ovarian torsion [134,135] (see 'Clinical presentation' above and 'Physical examination' above). Radiologic diagnosis is limited. In one case series, the most consistent finding on either pelvic ultrasound or computed tomography was a midline cystic mass (either in the posterior cul-de-sac or superior to the uterus) associated with a normal ipsilateral ovary [134]. Ultimately, the diagnosis is generally made at the time of surgical exploration. As with ovarian torsion, prompt consideration of this diagnosis and surgical detorsion may prevent irreversible ischemic damage. (See 'Management' above.)

Paratubal, broad ligament, or paraovarian cyst torsion — Torsion of paratubal, broad ligament, or paraovarian cysts may also occur [136-138]. The incidence is uncertain but should be suspected in a patient with acute or intermittent pelvic pain who has a paratubal cyst identified on pelvic ultrasound. The diagnosis of torsion can be made only with surgical evaluation. These cysts can easily be removed at the time of surgery without compromise of the ovary or fallopian tube. (See "Adnexal mass: Differential diagnosis", section on 'Paraovarian/paratubal cysts and tubal and broad ligament neoplasms'.)

Paraovarian cysts are often incorporated in the broad ligament close to the fallopian tube and may increase the risk of tubal torsion [137,139,140]. In such cases, the fallopian tube is often distended, and if torsion occurs, the cyst must be removed with great care to avoid compromise of tubal function. If cystectomy cannot be performed because of surrounding edema, a two-staged procedure may be helpful so as not to further compromise vascular perfusion; this is discussed in more detail above. (See 'Premenopausal patients with a viable, nonmalignant ovary: Detorsion' above.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Ovarian and fallopian tube disease".)

SUMMARY AND RECOMMENDATIONS

●Clinical significance – Ovarian torsion refers to the complete or partial rotation of the ovary on its ligamentous supports, often resulting in ischemia (picture 1). It is one of the most common gynecologic emergencies and prompt diagnosis is important to preserve ovarian and/or tubal function and to prevent other associated morbidity. The fallopian tube often twists along with the ovary; when this occurs, it is referred to as adnexal torsion. (See 'Introduction' above.)

●Epidemiology – Ovarian torsion occurs in females of all ages, but most cases occur in patients of reproductive age. It is one of the most common gynecologic emergencies. (See 'Epidemiology' above.)

●Risk factors – The primary risk factor for ovarian torsion is an ovarian mass, especially when the ovary is larger than 5 cm in diameter. However, torsion may also occur without an underlying lesion, particularly in the pediatric population. (See 'Risk factors' above and 'Pediatric patients' above.)

●Clinical presentation – The classic presentation of ovarian torsion is the acute onset of pelvic pain, often with nausea and vomiting, in a patient with an adnexal mass. A history of recent vigorous activity or a sudden increase in abdominal pressure may be an inciting event. (See 'Clinical presentation' above.)

●Diagnostic evaluation – Pelvic imaging, preferably with ultrasound, is the mainstay of evaluation in patients in whom ovarian torsion is suspected. (See 'Diagnostic evaluation' above and 'Imaging studies' above.)

●Diagnosis – A definitive diagnosis of ovarian torsion is made by direct visualization of a rotated ovary at the time of surgical evaluation. A presumptive diagnosis of torsion can be made with a fair degree of confidence in the presence of acute pelvic pain and imaging demonstrating an adnexal mass with an appearance consistent with torsion (particularly if pain is elicited when scanning over the adnexa with a vaginal ultrasound probe). Additional findings, such as nausea, fever, and pelvic tenderness on examination, further support the diagnosis. (See 'Diagnosis' above.)

●Management

•For most premenopausal patients with torsion of a nonmalignant ovary, we suggest detorsion and ovarian conservation rather than salpingo-oophorectomy, even in the case of a darkened, enlarged ovary (Grade 2C) (algorithm 1). Detorsion is standard practice for such patients, given a possible improvement in fertility outcomes with this strategy. Ovarian cystectomy is often performed along with detorsion if a benign mass is present. (See 'Premenopausal patients with a viable, nonmalignant ovary: Detorsion' above and 'Surgical evaluation' above.)

•Patients with an obviously necrotic ovary or an ovarian mass that is suspicious for malignancy require salpingo-oophorectomy (algorithm 1). Salpingo-oophorectomy is also performed in postmenopausal patients. (See 'Other patients: Salpingo-oophorectomy' above and 'Surgical evaluation' above.)

•For premenarchal patients with ovarian torsion and a normal ovary, we suggest oophoropexy in addition to detorsion rather than detorsion alone (Grade 2C). Patients with normal ovaries may be at higher risk of recurrent torsion than those with an ovarian mass. Detorsion without oophoropexy (but with cyst drainage or cystectomy) is performed when a mass is present. (See 'Pediatric patients' above and 'Prior ovarian torsion' above.)

●Torsion of other structures – Isolated torsion of the fallopian tube is uncommon but may also occur and result in an adverse impact on tubal function (picture 5). Tubal torsion occurs most commonly in the midportion of the tube itself but may also occur around the ligamentous supports of the tube. In addition, torsion of paratubal or paraovarian cysts may occur. (See 'Torsion of other adnexal structures' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Whitfield Growdon, MD, FACS, who contributed to earlier versions of this topic review.