Oophorectomy and ovarian cystectomy

INTRODUCTION — Ovarian pathology can occur at any time from fetal life to menopause. The most common surgical procedures for benign ovarian disease will be reviewed here.

General principles of the evaluation and management of an adnexal mass, elective oophorectomy at the time of hysterectomy, and surgical treatment of ovarian cancer are discussed separately. (See "Approach to the patient with an adnexal mass" and "Elective oophorectomy or ovarian conservation at the time of hysterectomy" and "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Surgical staging".)

OOPHORECTOMY VERSUS CYSTECTOMY — The indications for ovarian surgery versus expectant management of an ovarian cyst depend upon the patient's age, findings on pelvic examination, imaging, and laboratory results. These issues are discussed in depth separately. (See "Approach to the patient with an adnexal mass" and "Adnexal mass: Differential diagnosis".)

When surgery is indicated for benign ovarian disease, preservation of as much ovarian cortex as possible (via cystectomy or enucleation of a solid tumor from the ovary), is generally preferable to complete oophorectomy. When the ovary cannot be salvaged or insufficient viable tissue remains after attempts at conservation, oophorectomy is usually performed. Traditionally, less effort was made to preserve ovarian function in postmenopausal patients because of the thought that the ovary no longer functioned. That is no longer believed to be the case as studies have refuted this and support the notion that there is a lower all-cause mortality in patients who preserved ovarian function up to age 65 compared with those who had elective oophorectomy [1].

Indications for oophorectomy include:

●Benign ovarian neoplasms that are not amenable to treatment by a lesser procedure (eg, cystectomy, enucleation, partial oophorectomy).

●Elective or risk-reducing salpingo-oophorectomy with or without hysterectomy. (See "Elective oophorectomy or ovarian conservation at the time of hysterectomy".)

●Adnexal (ovarian) torsion with necrosis (rare). (See "Ovarian and fallopian tube torsion".)

●Ovarian malignancy. (See "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Surgical staging".)

●Tubo-ovarian abscess unresponsive to antibiotics. (See "Epidemiology, clinical manifestations, and diagnosis of tubo-ovarian abscess".)

●Definitive surgery for endometriosis. (See "Endometriosis: Treatment of pelvic pain" and "Female infertility: Reproductive surgery" and "Endometriosis: Management of ovarian endometriomas".)

●Gastrointestinal or other metastatic cancer (eg, breast, lung, melanoma) – Gastrointestinal cancer often metastasizes to the ovary. In one study, ovarian metastases were encountered in 25 percent of patients with an adenocarcinoma of the gastrointestinal tract; the metastases were occult in approximately one-half of these cases [2]. More data suggest this incidence may be lower [3]. Therefore, oophorectomy and concomitant hysterectomy at the time of resection of gastrointestinal cancer should be individualized based on the patient's age, type of malignancy, and location of disease.

●Patients with complete androgen insensitivity syndrome, in whom the procedure is termed "gonadectomy" – An increased risk of gonadal malignancy occurs in phenotypic females with a Y chromosome in their karyotype [4-7]. These individuals should have their gonads removed to avoid the 20 to 30 percent risk of malignant tumors arising in this tissue [7-9]. Gonadectomy is delayed until after pubertal development as it is rare to develop a malignancy before 20 years of age. (See "Ovarian germ cell tumors: Pathology, epidemiology, clinical manifestations, and diagnosis", section on 'Association with gonadoblastoma'.)

Gonadal streaks can be difficult to see and may lie very close to the external iliac artery or be herniated into the inguinal canal (figure 1). This operation can be safely performed using a minimally invasive approach; rarely is there a need for laparotomy. There is no need to remove the uterus or the fallopian tubes; these organs can be preserved to permit future childbearing using donor oocytes.

ASPIRATION AND FENESTRATION VERSUS CYSTECTOMY — Aspiration of cyst contents is not recommended because no tissue is obtained for histopathology and cytology of cyst fluid is not reliable for exclusion of malignancy. Cystectomy is the preferred operation for a benign ovarian cyst.

While aspiration resulted in cyst resolution in 37 percent of patients in one study, the high rate of recurrence (up to 65 percent) and high complication rate (2.6 percent) make it an ineffective option for the management of low-risk adnexal cysts [10-12]. Furthermore, aspiration does not provide better results than simple observation. These problems are less common with fenestration (ie, removing a full-thickness, square portion of the cyst wall to create a window); however, cystectomy is still preferable. If the cyst is malignant, spillage of malignant cells into the peritoneal cavity is possible with both aspiration and fenestration.

Aspiration followed by sclerotherapy via injection of methotrexate, tetracycline, alcohol, or erythromycin has been associated with a lower rate (4 to 38 percent) of cyst persistence or recurrence in observational series [12-16]. However, it is not clear that this intervention is more effective than expectant management because the studies were not adequately controlled.

SURGICAL APPROACH

Open laparotomy versus minimally invasive surgery — Most ovarian surgeries are for benign disease and are typically performed via a minimally invasive surgical (MIS) approach. In one large cohort study in the United States including patients undergoing oophorectomy or ovarian cystectomy for benign disease, MIS was utilized in almost 90 percent of cases [17]. The major advantages of MIS over laparotomy are reductions in recovery time, hospital stay, cost, and adhesion formation, which is particularly important for patients in whom fertility is an issue [18,19]. Limited data from randomized trials also showed less febrile morbidity and a lower frequency of urinary tract infection, postoperative pain, and postoperative complications with MIS [20] (see "Overview of gynecologic laparoscopic surgery and non-umbilical entry sites"). Guidelines for preoperative referral to a gynecologic oncologist are described in the table (table 1).

A disadvantage of an MIS oophorectomy/cystectomy is the potential for spill of cancer cells if the mass is malignant (see 'Spillage of malignant cells' below). Unfortunately, neither preoperative clinical and sonographic evaluation nor the laparoscopic appearance of the ovary can reliably predict which masses are malignant. However, with appropriate patient selection, these risks can be minimized. A survey by the American Association of Gynecologic Laparoscopists reported unsuspected ovarian cancer was found in only 0.04 percent of 13,739 cases of laparoscopic ovarian cyst surgery [21].

Sonographic criteria suggestive of ovarian malignancy are available online [22,23] (see "Adnexal mass: Ultrasound categorization"). In general, a thin-walled, unilocular simple cyst is likely to be benign, even in postmenopausal patients. Two series including approximately 1000 thin-walled, unilocular cysts in both premenopausal and postmenopausal patients found no malignant tumors under 75 mm [24,25]. A separate series of 219 patients with simple cysts up to 10 cm were managed successfully [26]. Thus, these cysts can usually be managed laparoscopically. An in-depth discussion of the approach to evaluation and management of adnexal masses can be found separately. (See "Approach to the patient with an adnexal mass" and "Adnexal mass: Differential diagnosis".)

There is increasing sentiment to evaluate some complex cysts with MIS because most of them are benign. There are no dogmatic recommendations for this group of patients, and clinicians must individualize treatment according to their index of suspicion. The concern associated with the use of MIS in this setting is that the prognosis may be worsened by cyst rupture if malignancy is encountered, although this is unproven. One must take into account the patient's age, medical conditions, clinical examination (eg, fixed mass or mobile), sonographic appearance of the mass, and tumor markers (eg, cancer antigen 125) to gauge the likelihood of malignancy when deciding upon the proper operative approach. MIS should be reserved for those cases in which the risk of malignancy is low, or if a malignancy is encountered, the patient should have immediate access to appropriate surgical staging and definitive treatment, preferably with the assistance of a gynecologic oncologist (table 2). Staging and treatment of ovarian cancer via an MIS approach are still under investigation, but this approach is becoming more commonly used [27]. (See "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Clinical features and diagnosis".)

Another approach is minilaparotomy, which some surgeons consider a minimally invasive procedure. Minilaparotomy has the advantages of a potentially shorter operating time and learning curve than laparoscopy and avoidance of pneumoperitoneum, but without the large incision associated with classical open laparotomy [28]. The procedure is performed by placing the patient in a steep Trendelenburg position and making a small suprapubic incision (4 to 9 cm) beneath the pubic hair line [29]. The abdominal fascia is opened 2 to 3 cm above the skin incision and the peritoneum is opened manually. Narrow Deaver retractors are used to allow frequent repositioning to optimize exposure of the surgical field. The following criteria should be met if this approach is employed: use of narrow instruments; good lighting; exteriorization of the target organ; combined, unidirectional maneuvering of all the retractors; and prompt hemostasis by electrocoagulating forceps. A comparable approach is the use of minilaparotomy, or a "hand assist" port, at the time of laparoscopy for the purpose of specimen retrieval and manipulation. This also has the added advantage of a quick recovery as the majority of the operation is done laparoscopically.

In summary, MIS is the preferred technique for oophorectomy/cystectomy because it is associated with fewer complications, faster recovery, and lower cost than laparotomy. Situations in which laparotomy may be more appropriate than MIS include the presence of dense adnexal adhesions, when the ovary is very large, or when there is a high suspicion of malignancy.

Surgeons must use good judgment and be selective in the cases chosen for MIS treatment. The following criteria are generally accepted guidelines:

●The MIS approach is reasonable for patients whose preoperative evaluation suggests benign disease [23]. These patients include those with probable dermoids, endometriomas, or physiological cysts that have not resolved with conservative management or are associated with acute symptoms. A laparoscopy may be converted to a laparotomy if the surgeon encounters a difficult dissection. (See "Overview of gynecologic laparoscopic surgery and non-umbilical entry sites".)

●Intraoperative findings suspicious for malignancy (ascites, enlarged nodes, matted bowel, excrescences, multiple nodular areas) traditionally warrant conversion to an open evaluation, but the use of MIS in this setting is still evolving. However, a smooth appearance on the surface of the cyst does not exclude the possibility of a malignancy.

●Removing cysts in a specimen bag reduces both operating time and spillage. Controlled intraperitoneal spillage of benign cyst contents (eg, cystic teratoma) does not increase postoperative morbidity as long as the spillage is aspirated and the peritoneal cavity is lavaged.

●Cysts that are complex should be removed, not fenestrated, given the possibility of malignancy and high recurrence rates.

●A solid adnexal mass that is small enough to be removed intact via colpotomy or via a laparoscopic bag can be managed with MIS. Solid masses can also be mobilized via MIS and then removed through a minilaparotomy incision or morcellated inside a specimen bag.

Use of robotic or single-port laparoscopy — Newer minimally invasive approaches, such as robot-assisted or single-port laparoscopy (also referred to as laparoendoscopic single-site surgery [LESS]), may also be used for oophorectomy or ovarian cystectomy.

There are few data regarding robot-assisted laparoscopic salpingo-oophorectomy. In one retrospective cohort study comparing patients who underwent adnexectomy using robot-assisted (n = 85) or conventional laparoscopy (n = 91) [30], no differences were found between surgical approaches regarding blood loss, intraoperative complications, or length of hospital stay. Operative duration was 12 minutes longer for robot-assisted versus conventional procedures. The study authors commented that they prefer to approach large adnexal masses with conventional laparoscopy because trocar placement is more flexible, manipulation of large masses is easier, and intraoperative drainage can be accomplished.

Ovarian surgery using a LESS approach is a developing field [31-34]. Improvements in postoperative pain and cosmetic results were reported by a randomized trial (n = 60) that compared LESS with conventional laparoscopy for oophorectomy or ovarian cystectomy [35]. Operative duration and complication rates were similar for the two approaches.

PROCEDURE

Oophorectomy — Oophorectomy may be performed through an abdominal incision, laparoscopically, or vaginally (at the time of hysterectomy).

Open or laparoscopic approach — After the abdomen is entered, pelvic and abdominal washings are obtained and saved to use for staging if a malignancy is subsequently diagnosed. The entire pelvis, abdomen, and retroperitoneum (eg, diaphragm, omentum, viscera, kidneys) are inspected for lesions suspicious for carcinoma (excrescences, thick adhesions, nodules, enlarged nodes). If present, these lesions should be biopsied and sent for frozen section.

If findings are consistent with benign disease, the infundibulopelvic ligament and ureter are identified. The peritoneum is incised parallel to the ovarian vessels, and the retroperitoneal space is entered. Alternatively, the round ligament can be divided to enter the retroperitoneal space.

Using either blunt or sharp dissection, the broad ligament is opened and the ureter identified on its medial, or posterior, leaf.

If the fallopian tube is to be removed, the ovarian vessels are then elevated to allow good visualization of the nearby ureter. The vessels are clamped, divided, and the pedicles ligated 1 to 2 cm above the ovary to ensure hemostasis and complete removal of the ovary (figure 2A-C). Both the ovarian ligament and fallopian tube are clamped parallel and just lateral to the uterine cornu and then excised; the cornu is then ligated. When performed laparoscopically, the pedicles are sealed or coagulated, and cut, with the surgeon's choice of instrument and energy source. These are reviewed elsewhere. (See "Instruments and devices used in laparoscopic surgery", section on 'Electrosurgery'.)

If the fallopian tube is to be preserved, the multiple tubal branches of the ovarian artery should be clamped and ligated inferior and parallel to the tube in a systematic fashion during an open procedure. Alternatively, a laparoscopic vessel sealing device can be used, even at the time of laparotomy. This separates the ovary from the fallopian tube and allows clear visualization of the ovarian branch of the uterine artery. Subsequently, the ovarian artery can be clamped, divided, and ligated. The utero-ovarian ligament is then clamped parallel and just lateral to the uterine cornu and excised; the cornu is then ligated. Options for laparoscopic instruments are reviewed elsewhere. (See "Instruments and devices used in laparoscopic surgery", section on 'Electrosurgery'.)

Some surgeons advocate performing a wedge resection of the fallopian tube stump and approximating the surrounding cornual edge of myometrium to decrease the chance of a uteroperitoneal fistula, ensure hemostasis, and prevent the theoretical risk of a cornual ectopic pregnancy. There are no data to support or refute this approach, which may add to the total blood loss and duration of the procedure.

In open cases, microsurgical techniques and fine absorbable suture material may help to minimize postsurgical tubal adhesions.

Minimally invasive surgery instruments — There are several methods for performing an oophorectomy with minimally invasive surgery.

●Bipolar electrosurgery – The infundibulopelvic ligament is grasped with bipolar forceps, elevated off of the ureter, and desiccated after visually ascertaining that the ureter is clear of this area. The ligament is then transected with endoscopic scissors and the broad ligament incised up to the utero-ovarian ligament. The medial attachments of the adnexa to the uterus, including the blood supply, can also be desiccated with the bipolar forceps or tied off using endoscopic loop ties and then excised.

●Stapling devices – Endoscopic stapling devices are a less popular method for controlling the various attachments to the ovary since they are usually more difficult to manage, require larger trocars, and are more expensive. The ureter, which can be easily caught in the jaws of the stapling device, must be carefully identified, and excluded from the area being crushed and stapled.

●Ultrasonic cutting and coagulation device – An ultrasonic cutting and coagulation device uses ultrasonic vibration, which denatures protein and generates secondary heat, resulting in coagulation. The device contains a cutting blade that allows for fewer instrument changes. This device can be used to cut across the mesovarium, utero-ovarian ligament, or the ovarian vessels. Care must be taken to visualize the ureter and prevent catching it in the blades.

●Bipolar vessel sealing device – Bipolar vessel sealing devices use bipolar current and pressure to seal vessels. Many of these devices have a blade that is activated to cut tissue. As with an ultrasonic cutting and coagulation device, care must be taken to ensure the ureter is free of blades before firing.

●Loop technique – The most common loop technique is to slip the ovary through two or three pretied loops that have been introduced through a separate puncture site. The adnexa must be free of adhesions and mobile before placing the loops; this occasionally requires lysis of adhesions and incising the mesosalpinx to facilitate placement. The loops are cinched down around the vascular pedicles (figure 3) and then the adnexa is excised distal to the loops. The ureter must be visualized before and after this procedure to insure that it has not been pulled into the pedicle or kinked. Visualization is achieved by observing peristalsis through the peritoneum or, preferably, by opening the peritoneum and directly observing the ureter.

Cystectomy — After the abdomen is entered, pelvic and abdominal washings are obtained and saved to use for staging if a malignancy is subsequently diagnosed. The entire pelvis and abdomen (eg, diaphragm, viscera, omentum) are inspected for carcinoma; suspicious sites (excrescences, adhesions, nodules, enlarged nodes) should be biopsied and sent for frozen section.

Before actually performing the cystectomy, all adhesions should be carefully divided to allow proper mobilization of the ovary and restore the normal relationship between it and the other pelvic structures.

Open cystectomy — An elliptical incision is made over the thin ovarian cortex in the axis of the ovary and over its most dependent area (figure 4A-B). The area adjacent to the fallopian tube and the fimbria ovarica should be avoided to limit potential injury to the fallopian tube.

In addition, the risk of adhesion formation is minimized by avoiding excessive handling of the ovary. After the initial incision, the back of the knife handle or scissors can be used to develop the plane between the cyst wall and the ovarian cortex to shell out the cyst while applying counter traction with an Allis clamp on the cortex. Occasionally, the base of the cyst is very adherent to the ovarian stroma and requires excision with scissors or electrocautery.

Every attempt should be made to remove the cyst intact; however, if the cyst ruptures, care should be taken to control the spill and avoid gross contamination of the abdominal cavity (see 'Spillage of malignant cells' below). This can usually be achieved by packing the surrounding areas with surgical packs and carefully placing a clamp across the defect in the cyst wall. In the event of a cyst rupture, the abdominal cavity should be copiously irrigated to decrease the risk of both pseudomyxoma peritonei and chemical peritonitis, admittedly rare occurrences.

After removal of the cyst, the deep tissues of the ovary can be left open if hemostasis is adequate (preferable), or reapproximated if hemostasis is needed, avoiding sutures on the capsule of the ovary. The ovarian cortex may appear thin but should not be trimmed, because this may remove viable ovarian tissue. Reoperation of these cases has revealed ovaries that have resumed normal shape and anatomic relationships despite their appearance at the initial surgery. Adhesion-prevention barriers such as modified oxidized regenerated cellulose membranes can be applied over the ovarian defects and appear to reduce the incidence and severity of postoperative adhesion formation [36]. (See "Postoperative peritoneal adhesions in adults and their prevention".)

If multiple cysts are present, the least number of incisions possible should be made on the surface of the ovary. An oophorectomy should not be performed even if a major portion of an ovary is removed. Pregnancies have been reported in patients with less than 25 percent of one ovary remaining.

Laparoscopic/minimally invasive surgery cystectomy — The laparoscope is inserted periumbilically and other trocar sites are usually placed 5 to 6 cm laterally on either side. Occasionally, a suprapubic port may be used. The periumbilical site is usually reserved for the camera, the midline suprapubic puncture site is generally used for suction/irrigation, and the lateral sites are used for stabilization of the ovary. (See "Overview of gynecologic laparoscopic surgery and non-umbilical entry sites".)

After a thorough inspection of the abdominal cavity and the ovarian cyst to visually confirm no suspicion of malignancy, the utero-ovarian ligament is grasped, and the ovary stabilized. As with an open procedure, all adhesions should be lysed prior to beginning cyst removal. An intact removal of the cyst is preferable, if one can dissect the cyst off the surrounding ovarian cortex. If not, a cystotomy can be performed in a controlled fashion, as described below.

●To perform a cystectomy:

•Intact – The ovarian cortex overlying the cyst and closest to the native ovary is incised, usually with energy or surgical scissors taking special care not to enter the cyst. This incision is extended circumferentially around the base of the cyst where it is attached to the portion of the ovary that will remain in situ. The space between the cyst and the ovarian cortex is then developed, typically with blunt dissection but occasionally with electrocautery, until the cyst is separated from the remaining ovary. Some ovarian cysts lend themselves to intact resection and retrieval through a specimen bag introduced laparoscopically into the peritoneal cavity (or through a minilaparotomy incision). One should take care not to puncture the bag or spill its contents. The bag can be removed through a secondary port or through the infraumbilical trocar site after the port has been removed. Removal of an intact cyst may, in some cases, actually facilitate the dissection from the ovarian stroma. (See "Overview of gynecologic laparoscopic surgery and non-umbilical entry sites".)

•Cystotomy – The cyst is stabilized with graspers and an endoscopic suction/irrigator is used to control any spill. The cyst is then punctured with a 16- to 18-gauge needle or with cautery. The cystotomy is extended to allow introduction of the suction/irrigator into the cyst. The cyst contents are aspirated, and the cyst cavity is irrigated thoroughly.

The cystotomy is then extended in the direction of the ovarian axis, and the internal walls of the cyst are inspected. If no suspicious areas are encountered, the cyst wall is grasped and it is dissected off the ovarian stroma with blunt or sharp dissection using endoscopic scissors, electrosurgery, a blunt probe, or a laser. The forceps grasping the cyst wall can be rotated to assist in the dissection and actually peel away the cyst wall from the surrounding ovary (figure 5A-C). Incomplete areas of excision can be sharply excised or fulgurated to destroy the lining cells.

If the cyst bed is hemostatic, it can be left to heal by secondary intention. Any suturing that is done should avoid the surface of the ovary. Cautery is also very effective for hemostasis but should be kept to a minimum to reduce tissue destruction. Adhesion-prevention barriers such as oxidized regenerated cellulose (Interceed, TC7) can be applied through the laparoscope to deter adhesion formation [37].

●Endometriomas – It is particularly important to remove all of the cyst when dealing with endometriomas to prevent recurrences and improve reproductive outcome. Fulguration can be used to destroy areas that cannot be excised [38]. (See "Endometriosis: Management of ovarian endometriomas".)

●Mature teratomas (dermoid cysts) – When dermoid cystectomy is performed, care should be taken to irrigate extensively after cystotomy. Persistence of teratoma fluid may cause peritonitis. (See "Ovarian germ cell tumors: Pathology, epidemiology, clinical manifestations, and diagnosis", section on 'Mature cystic teratomas'.)

●Large cysts – A variety of approaches to laparoscopic removal of large cysts (10 cm or greater) have been suggested. Large cysts can be aspirated, either preoperatively using ultrasound guidance [39,40] or intraoperatively after placing the cyst in a laparoscopic specimen bag [41]. Performing open laparoscopy may avoid puncture of the cyst during initial placement of laparoscopic instruments [42,43]. To reduce the risk of intraperitoneal spillage, laparoscopically guided minilaparotomy can be used for large cysts [44]. If ovarian conservation is planned, the presence of a large cyst should not change the surgeon's goal. No matter how large the cyst, it is usually possible to save ovarian cortex and hormonal function.

POSTOPERATIVE ISSUES — Ureteral injuries have been reported with open or minimally invasive surgery (MIS) oophorectomy when ureteral identification was performed incorrectly. Although the ureter can be seen through the peritoneum in many patients, in others, the peritoneum must be opened and varying degrees of dissection carried out to expose it. Additional potential complications related to the MIS approach are listed in the table (table 3).

Spillage of malignant cells — Capsule rupture of an ovarian tumor may worsen prognosis, although data are mixed and not definitive. Such patients are often administered chemotherapy, unless the tumor is well differentiated. (See "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Surgical staging", section on 'Avoidance of intraoperative tumor rupture' and "First-line chemotherapy for advanced (stage III or IV) epithelial ovarian, fallopian tube, and peritoneal cancer".)

Ovarian remnant syndrome — Ovarian remnant syndrome (ORS) occurs in patients who have undergone bilateral oophorectomy and subsequently present with symptoms related to ovulatory function from ovarian tissue inadvertently left behind. In rare cases, the remaining ovarian tissue may be from congenital supernumerary ovaries. It should be distinguished from the residual ovary syndrome (ROS), in which the ovary was intentionally preserved and subsequently developed pathology.

Failure to skeletonize the infundibulopelvic ligament and placement of a clamp that is not sufficiently lateral to the ovary may result in retention of a piece of the ovary in the pedicle, leading to ORS. This is more common when the procedure is complicated by dense adhesions (eg, endometriosis, pelvic inflammatory disease), neoplastic disease, and increased pelvic vascularity [45]. Intraoperative bleeding, anatomic variation, or deviation from sound surgical principles also contribute to incomplete removal of ovaries. Blunt dissection to free the ovaries from surrounding tissues must be avoided because it risks leaving behind remnants of the ovarian cortex, which can become neovascularized by the adjacent pelvic peritoneum or viscera [46].

The typical patient presents with cyclic pelvic pain and a mass, although the pain may be persistent with acute flare-ups. Occasionally, an asymptomatic mass is detected on pelvic or sonographic examination. Ureteral obstruction may occur.

ORS is probably present if a follicle-stimulating hormone (FSH) level is in the premenopausal range or if serum estradiol levels are normal after bilateral oophorectomy; however, some patients with ORS have postmenopausal levels of FSH and estradiol [46]. Other signs suggestive of the syndrome are cyclic menstruation in a patient whose uterus had been retained at bilateral oophorectomy and relief of symptoms after medical therapy that suppresses ovarian function (eg, danazol, gonadotropin-releasing hormone agonists, combined hormonal contraception). After unilateral oophorectomy, the diagnosis is suggested by the typical clinical manifestations combined with a pelvic mass on the side of the oophorectomy.

In one large series (n = 186 cases), ultrasound examination showed a pelvic mass in 93 of 100 patients who had preoperative testing; computed tomograms were positive for a pelvic mass in 67 of 73 patients, and magnetic resonance imaging identified a mass in 7 of 9 patients [46]. If ORS is suspected but imaging is negative, one group suggested repeated imaging after ovarian stimulation with clomiphene citrate [47].

The surgical treatment of ORS is to excise the remaining ovarian tissue, a procedure that is usually difficult and requires meticulous dissection to delineate the normal anatomy in an otherwise abnormal pelvis. The ureter must be identified, and both it and the bowel may have to be mobilized clear of the pelvic side wall. The remnant is usually encased in adhesions and frequently is retroperitoneal; therefore, the best approach is through the retroperitoneum. Skilled and experienced surgeons may approach ovarian remnants using MIS techniques [48-51], but it is prudent to have consent for laparotomy, which may be required to complete the procedure.

The remnant may be difficult to delineate from the surrounding tissues if a definite mass or cyst is not present. Superovulating the remnant before the operation may facilitate identification and successful excision. The key to being sure the ovary is removed is to identify the infundibulopelvic ligament and to transect all tissue attachments of ovarian tissue allowing several millimeters of margin.

Fertility following unilateral oophorectomy — There are few data regarding fertility following unilateral oophorectomy. Fertility following removal of one ovary had been studied most frequently in patients with ovarian cancer or tumors of low malignant potential who undergo conservative surgery. In these patients, literature reviews have reported widely varying pregnancy rates, ranging from 42 to 88 percent [52,53].

For patients undergoing in vitro fertilization, data are mixed regarding whether patients with a single ovary have a lower conception rate [54]. However, in one meta-analysis including 21 retrospective studies, patients with one ovary compared with two ovaries had lower quantity (eg, fewer follicles; -2.7 follicles/cycle; 95% CI -3.4 to -1.9), but similar quality (eg, pregnancy rates), of the ovarian pool [55]. This affect likely varies with age as younger patients have more follicles per ovary.

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: Gynecologic surgery".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Beyond the Basics topics (see "Patient education: Ovarian cysts (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Determining type of procedure

•The indications for ovarian surgery versus expectant management of an ovarian cyst depend upon the patient's age, findings on pelvic examination, imaging, and laboratory results. (See 'Oophorectomy versus cystectomy' above.)

•When surgery is indicated for benign ovarian disease, preservation of ovarian cortex is often possible via cystectomy or enucleation of a solid tumor from the ovary and is generally preferable to complete oophorectomy. When the ovary cannot be salvaged or insufficient viable tissue remains after attempts at conservation, oophorectomy is performed. (See 'Oophorectomy versus cystectomy' above.)

•Data in postmenopausal patients demonstrate a potential benefit to preserving an otherwise normal ovary up to age 65. (See 'Oophorectomy versus cystectomy' above.)

●Procedures not recommended – Aspiration of cyst contents is not recommended because no tissue is obtained for histopathology, cytology of cyst fluid is not reliable for exclusion of malignancy, there is a high rate of recurrence, and aspiration does not provide better results than simple observation. These problems are less common with fenestration (ie, removing a full-thickness, square portion of the cyst wall to create a window), but cystectomy is preferable to either of these techniques. (See 'Aspiration and fenestration versus cystectomy' above.)

●Spillage – When performing oophorectomy in a patient in whom malignancy is suspected, rupture of an ovarian cyst should be avoided to prevent tumor dissemination. (See 'Spillage of malignant cells' above.)

●Ovarian remnant – Ovarian remnant syndrome (ORS) occurs in patients who have undergone bilateral oophorectomy and subsequently have symptoms related to ovulatory function from ovarian tissue inadvertently left behind. After unilateral oophorectomy, the diagnosis is suggested by these symptoms combined with a pelvic mass on the side of the oophorectomy. ORS should be distinguished from the residual ovary syndrome (ROS), in which the ovary was intentionally preserved and subsequently developed pathology. (See 'Ovarian remnant syndrome' above.)

●Fertility – There are some data regarding fertility following unilateral oophorectomy that support that patients with unilateral oophorectomy have fewer follicles but similar pregnancy rates to patients with both ovaries. The impact likely varies with age as younger patients have more follicles per ovary. (See 'Fertility following unilateral oophorectomy' above.)