Clinical characteristics, treatment and outcome of adnexal torsion in pregnant women: 10-year experience

Background Adnexal torsion during pregnancy is a gynecological emergency. Delayed diagnosis and treatment can cause ovarian necrosis and fetal loss. This study assessed the clinical characteristics, treatment and outcomes of adnexal torsion in pregnant women. Methods A retrospective study was conducted at a tertiary center between January 2008 and January 2018. Eighty-two pregnant women with surgically confirmed adnexal torsion were included. The clinical characteristics, ultrasound data, surgical interventions and pregnancy outcomes were analyzed. Results The median age of the patients was 28 (range, 18–38) years. The median gestational age was 11 (range, 6–31) weeks: 53 were in the first trimester, 21 (25.6%) were in the second trimester, and 8 (9.8%) were in the third trimester. The most common symptoms and signs were sudden pelvic pain (100%) and adnexal or pelvic masses (97.6%), followed by nausea and vomiting (61%). The Doppler blood flow signal disappeared in 62.5% of the patients. Sixty-three (76.8%) patients underwent laparoscopy, and 29 (24.2%) underwent laparotomy. The median gestational age in patients undergoing laparotomy was higher than that in those laparoscopy (26 weeks vs 10 weeks, p < 0.001). Fifty-three (64.6%) patients underwent conservative surgery, with 48 detorsions and cystectomies, 2 detorsions and cyst fenestrations, 1 detorsion only and 2 salpingectomies only. Twenty-nine (25.4%) patients underwent unilateral salpingo-oophorectomy. There were no cases of postoperative thrombosis, spontaneous abortion or Seven patients underwent simultaneous artificial abortion. One patient experienced fetal and 74 patients had live births.


Background
Adnexal torsion (AT), a true gynecological emergency, is the fifth most common cause of acute pelvic pain in women of reproductive age [1].It refers to the complete or partial rotation of the adnexa age, symptoms and signs, and white blood cell count.The following surgical information was recorded: time from onset to surgery, surgical approach, surgical procedure, and postoperative complications.Pregnancy outcomes included live birth, gestational week of delivery, and newborn weight.The pregnancy outcome of patients who continued their pregnancy follow-up and delivered in our hospital was obtained from their medical records.A telephone interview was performed only for patients who delivered at other hospitals.Ultrasound scans were performed by sonographers in the emergency department.Surgery was performed by attending physicians in the gynecology department.
The surgical procedure was classified as conservative surgery or unilateral salpingo-oophorectomy (USO).Conservative surgery included detorsion with cystectomy, detorsion with cyst fenestration, detorsion only and salpingectomy only.The gestational trimesters were classified as follows: (1) first trimester, 12 weeks or before; (2) second trimester, 13-27 weeks; and (3) third trimester, 28 weeks and above.Spontaneous abortion related to surgery was defined as an abortion occurring within 2 weeks after surgery.Leukocytosis was defined as a white blood cell count > 11,000 cells/ml.The data analysis was carried out using SPSS 21.0 statistical analysis software (IBM Inc., Chicago, IL).
Continuous data were compared between groups using the t test or Mann-Whitney nonparametric test, as appropriate.Nominal variables were compared with either the chi-square or Fisher exact test.
Statistical significance was indicated at p < 0 .05.

Results
A total of 82 pregnant women who were diagnosed with AT by surgery were included in the study.The general clinical characteristics of the patients are shown in Table 1.The median age of the patients was 28 years (range, 18-38 years).Fifty-nine patients were nulliparous.Eighteen (22%) patients had had previous pelvic surgery.The median gestational age at onset was 11 weeks (range, 6-32 weeks).
Among the overall population, 53 (64.6%) were in the first trimester.Seven (8.5%) patients became pregnant by in vitro fertilization and embryo transfer (IVF-ET).All the patients complained of acute lower abdominal pain; 50 (61%) patents had nausea and vomiting.Only 3 (3.7%)patients had fever.
Laboratory studies revealed a mild elevation of the white blood cell count, and leukocytosis was found in 39 (47.6%) patients.IVF-ET: in vitro fertilization and embryo transfer Ultrasound examination was performed for all patients.The ultrasound characteristics of the adnexal mass are shown in Table 2.In all patients except two, an adnexal or pelvic mass could be detected on emergency ultrasound.The median largest diameter of the adnexal mass was 7 cm (range, 4-14 cm).

Discussion
In the present study, we summarized the characteristics, treatment and outcomes of AT in pregnant women over 10 years.Eighty-two patients were included.However, considering that the occurrence of AT during pregnancy is uncommon, the number of cases in our study is relatively large.Hasson [4] et al described a series of 118 patients with AT during a 10-year period in two tertiary centers, of which 41 patients were pregnant.Ginath [14] et al reported 54 cases of AT in pregnant women.
The accurate diagnosis of AT is often challenging, as the symptoms and signs of AT during pregnancy lack specificity.Consistent with other studies [13,14], most cases occurred in the first trimester but could occur even in the third trimester: 8 (9.8%) patients experienced AT in the third trimester.
Almost all patients were admitted to the emergency department because of acute or subacute low abdominal pain [7].Nausea and vomiting was another common manifestation after pain, with an incidence of up to 70% [2,4,5,15].AT can be misdiagnosed as other diseases that cause lower abdominal pain, such as appendicitis and renal colic [15].In the present study, three patients underwent laparotomy because of suspected appendicitis and were found to have AT during the operation.In addition, white blood cell counts may be slightly elevated.Chang [15] et al reported that 45% of patients had elevated white blood cells.Ginath [14] et al also revealed a slight elevation in white blood cell counts in pregnant women with AT compared with nonpregnant women.In our study, 47.6% of patients had leukocytosis, which was consistent with previous studies.
Ultrasound is the most common imaging method for evaluating acute abdominal pain during pregnancy in the emergency department.Color Doppler sonography has been recently proposed as a useful tool for improving the preoperative diagnosis of AT.However, some studies have demonstrated that the Doppler finding has a high false-negative rate.Smorgick [3] et al. reported that a normal Doppler flow was found in 60% of cases of AT in pregnant women.Hasson[4] et al described that only 39% of cases of AT in pregnant women showed no blood flow on the Doppler test.Ginath [14] et al reported that Doppler flow examination revealed the lack of arterial flow in 70% of pregnant women.
In the present study, 37.5% of the patients had a normal Doppler flow signal.The reason for the high false-negative rate may be that the severity of the vascular impairment is variable, depending on the number of twists, the tightness and the duration of torsion, which can cause partial or complete vascular obstruction.Therefore, the decision regarding surgery should not be made based on the findings regarding blood flow alone but based on the clinical suspicion of AT.In addition, the gravid uterus may displace the twisted mass so that the mass is not detected, which can lead to delayed diagnosis.In our study, ultrasound failed to reveal the twisted mass in 2 patients due to the enlarged uterus.There is increasing evidence that MRI can be used for the primary evaluation of acute abdominal pain in pregnancy, particularly when appendicitis cannot be excluded and a mass is not detected by ultrasound [16].
Similar to in nonpregnant women, laparoscopy has become a common and safe mode of surgical treatment for AT in pregnant women.Hasson[4] et al reported that laparoscopy was performed in 88% of pregnant women with AT.Daykan [6]et al conducted a study in which 85 pregnant women with AT were enrolled, and 78 (91.7%) patients underwent laparoscopy.In 2011, the Society of American Gastrointestinal and Endoscopic Surgeons stated that laparoscopy can be safely performed during any trimester of pregnancy and is recommended for the diagnosis and treatment of AT unless the clinical severity warrants laparotomy [17].Laparoscopy can be performed in the third trimester by experienced surgeons.Chohan [18] successfully performed laparoscopic surgery for a woman with fallopian tube torsion at 35 weeks of gestation.It has been confirmed that laparoscopic surgery does not affect obstetrical outcomes compared with laparotomy [15] and does not increase complications such as thromboembolism events, sepsis and spontaneous abortion.
Compared with nonpregnant women with AT, pregnant women were more likely to undergo conservative surgical management.Previous studies have shown that 30%~100% of patients underwent conservative surgical management, and detorsion only was the most common procedure [3,4,7,14].Although 53 (64.6%) patients underwent conservative surgery in our study, 48 underwent cystectomy.Interestingly, we found that cystectomy could significantly decrease the recurrence risk of AT.Hasson [4]et al reported that the rate of recurrence of AT for pregnant women who underwent detorsion only was 19.5%.Pansky [19]et al described that the recurrence rate of detorsion only was 20% and that there was no recurrence in patients who underwent cystectomy or oophorectomy.There was no recurrence in our study because 90.1% of the women in the conservative surgery group underwent cystectomy.This indicates that cystectomy removes the risk factors for recurrence.The twisted adnexal mass has edema and is fragile, which sometimes makes cystectomy difficult.In this situation, detorsion and fenestration for large cysts can be performed safely because most of the cases are benign masses.
Regrettably, more patients (35.5%, 29/82) in our study underwent USO than in previous studies [4,6,12,14].The decision to perform USO was at the discretion of the surgeon.Based on the descriptions in the surgical records in the present study, physicians preferred to perform USO if the color of the adnexa was still blue-black for ten minutes after detorsion.However, some studies have proven that it is not accurate to determine the activity of the ovary based on the color during the surgery [20][21][22].

Table 1
Clinical characteristics of patients

Table 2
Characteristics of ultrasoundThe median gestational age in the laparoscopy group was 10 weeks (range 6-28 weeks).The median gestational age in the laparotomy group was 26 weeks (range 8-31 weeks).The median gestational age in the laparotomy group was significantly larger than that in the laparoscopy group (p<0.001).The surgical and pathological characteristics are shown in Table3.The median interval between &: Doppler signals were tested in 48 patients.a:adnexal mass was not detected in 2 patients.All patients underwent an emergency surgical procedure for their initial treatment.Laparoscopy was performed in 63 patients (76.8%).There were no conversions to laparotomy in the laparoscopy group.3%) patients.The most common histopathological findings were benign, including corpus luteum cyst, serous cystadenoma, begin teratoma, follicular cyst, mesosalpinx cyst, ovarian endometrioma, mucinous cystadenoma, and ovarian clean cell carcinoma.Only 1 malignant lesion was found.

Table 3
Surgical and pathological characteristicsAll patients recovered well and had an uneventful postoperative course.No thrombotic events, sepsis or spontaneous abortion occurred after the operation.There was no recurrence of AT during subsequent pregnancies.The patients who underwent surgery in the first trimester received oral progesterone until 12 gestational weeks.