This chapter should be cited as follows:
Ottolina J, Grisafi G, et al, Glob. libr. women's med.,
ISSN: 1756-2228; DOI 10.3843/GLOWM.420993

The Continuous Textbook of Women’s Medicine Series – Gynecology Module

Volume 8

Gynecological endoscopy

Volume Editors: Professor Alberto Mattei, Director Maternal and Child Department, USL Toscana Centro, Italy
Dr Federica Perelli, Obstetrics and Gynecology Unit, Ospedale Santa Maria Annunziata, USL Toscana Centro, Florence, Italy

Chapter

Surgical Treatment of Ovarian Endometrioma

First published: September 2024

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INTRODUCTION

Endometriomas are fluid-filled ovarian cysts containing endometrial glands and stroma that affect approximately 17–44% of patients with endometriosis. Endometriomas are most often unilateral, with a mean cyst wall thickness of 1.2–1.5 mm. Bilateral endometriomas, when present, are associated with more extensive disease and posterior cul-de-sac obliteration. The left ovary is more commonly affected, with the sigmoid colon potentially preventing elimination of exfoliated endometrial fragments effluxing through the fallopian tubes during menstruation, allowing endometrial cells more opportunity to implant upon the left ovary.¹

Endometriomas may affect fertility through structural damage, inflammatory changes, and diminishment of ovarian reserve.² First, endometriomas may distort pelvic anatomy, negatively affecting the ability of the fallopian tubes to grasp an ovum. Second, endometriomas are associated with an increase in inflammatory markers in the peritoneal fluid, impairing tubal and sperm motility; the subsequent free radicals can affect embryo development. Third, endometriomas may also decrease ovarian reserve. It has been proposed that the increased fibrosis and inflammation within the ovary leads to oxidative stress and apoptosis. This oxidative stress and presence of free radicals may also affect oocyte quality; indeed, embryos from patients with endometriosis show slower development and arrest more frequently than those from patients without endometriosis. Finally, endometriomas also cause mechanical stretching of the ovarian cortex which can harm follicles.^3,4

There is no standardized surgical approach to the management of endometriomas, although several different surgical techniques are described. Cystectomy has long been the favored approach for complete surgical excision due to significant evidence of improvement in symptoms and decreased risk of recurrence compared to ablation.⁵ However, concerns have been raised as to the possibility that surgical excision may damage the ovarian reserve, which appears to be already damaged by the presence of the endometrioma itself.^6,7 Therefore, indication to surgical treatment should balance the possible risks of damaging the ovarian reserve with the advantages of surgery in terms of satisfactory pain relief rates and pregnancy rates, and of obtaining a tissue specimen to rule out the rare cases of unexpected ovarian malignancy.

SURGERY FOR ENDOMETRIOMA TREATMENT

The standard approach to ovarian endometrioma is laparoscopic excision of the cyst capsule with the stripping technique.⁵ Evidence-based guidelines suggest surgical excision in case of symptomatic or large (>3 cm) endometriomas.^8,9

Excision of the cyst capsule with the stripping technique (cystectomy) seems to be more beneficial than drainage and ablative techniques, since it provides a higher spontaneous pregnancy rate and lower recurrence rate.⁹

Cystectomy involves a “stripping” technique in which a plane between the cyst wall and normal ovarian cortex is created and then further delineated using traction and countertraction with atraumatic instruments. This can be exceptionally challenging due to the fibrosis and inflammation often encountered with the endometrioma, making it difficult to develop the correct surgical plane. For this reason, surgical excision of endometriotic cysts is a complex procedure that requires adequate competence and skill, and dedicated operators.

Recently, some concerns have been raised as to the possibility that surgical excision of the endometrioma, even when surgery is performed by skilled surgeons, may negatively impact on the ovarian reserve of the operated ovary.⁶ This effect is thought to be related to excessive removal and thermal destruction of healthy ovarian tissue with subsequent loss of ovarian follicles.¹⁰

Concerns about ovarian failure after cystectomy resulted in the introduction of ablative techniques using energies with minor in depth thermal spread, such as CO₂ laser or plasma energy. There are consistent data in the literature suggesting that this technique may represent an effective ovarian tissue-sparing technique.^11,12

Ablative technique appears to destroy the filmy superficial internal lining of the cyst selectively without reaching the fibrotic capsule surrounding the endometrioma or the adjacent healthy ovarian cortex.^13,14 Particularly, CO₂ fiber laser vaporization may represent a more advantageous approach than other energy sources (CO₂ laser in-line-of-sight or plasma laser) for several reasons. It is simple, easy to use, and has the advantage of eliminating the ‘surgeon’s experience’ factor as recently demonstrated in a study conducted by Vanni and co-workers.¹⁵ Thanks to its high precision, CO₂ fiber laser vaporization provides optimal coagulation and ablation capabilities, minimizing the need for electrocoagulation or suturing. Thanks to its low thermal energy, it avoids excessive ischemia and allows safe management of delicate tissues, such as ovarian parenchyma. Moreover, the long arm of the flexible fiber allows the surgeon to reach narrow anatomical spaces, and it can be introduced in the peritoneal cavity from any laparoscopic access, allowing the surgeon the optimal approach to the operative field.

Good results in terms of postoperative pregnancy rates, recurrence risk and ovarian response to controlled ovarian stimulation (COS) in IVF setting after ablation using energies with little thermal spread, such as CO₂ laser and plasma energy, have been published.^16,17

SURGICAL INSIGHTS

• First, place the patient on the operating table with their legs placed into stirrups.
• After administering general anesthesia, place the patient in the lithotomic position, a variation of the supine position in which the legs are separated from the midline in a 30° to 45° abduction with the hips flexed until the thighs form an angle between 80° and 100°.
• Establish a sterile field by cleaning the following areas with a sponge soaked in antiseptic solution: the apex of the umbilicus, the abdomen, the perineum, and the top third of the thighs. Then, scrub with a gauze drenched in iodine solution the vulva and, when possible, the vaginal interior up to the cervix and discard it. Repeat this step 3x.
• With a new sponge drenched in iodine solution, swab the anus twice and discard it. Dry the prepared external areas with a sterile towel and place sterile drapes. Insert a urethral catheter for continuous bladder drainage.
• When possible, with the use of an anterior and posterior vaginal retractor, expose the cervix and insert the uterine manipulator into the cervix. Create a pneumoperitoneum by either a Verres needle inserted at an angle of 45° in non-obese patients to 90° in obese patients) or using the open technique (a small, 1 cm incision is made below the umbilicus on the midline). Keep the insufflation pressure between 12 mmHg and 14 mmHg.
• Insert a laparoscope and inspect the upper and lower abdomen. After positioning the patient in a slight Trendelenburg position, place the other laparoscopic access (usually two or three).

Then, perform either CO₂ fiber laser ablation or stripping technique as described below.

STRIPPING TECHNIQUE

Cystectomy consists in stripping away the cyst wall from the underlying healthy ovarian parenchyma by delicate traction and countertraction maneuvers followed by selective hemostasis. However, endometrioma is a “pseudocyst” with no clear cleavage plan, thus the risk of inadvertent removal of healthy ovarian parenchyma is higher compared to other ovarian benign cysts especially in case of surgeons without an extensive expertise in the endometriosis surgical treatment. Endometrioma cystectomy, even when performed by an expert surgeon, may lead to significant ovarian tissue removal which increases proportionally as cyst diameter increases.¹⁸ Therefore, a team of surgeons with extensive experience in the treatment of endometriosis is required in order to keep at minimum the possibility of ovarian function damage.

Surgical technique

• Start with adhesiolysis in order to free the ovaries from the surrounding structures. Make a sharp cortical incision on the thinnest part of the cyst, just enough to identify the correct cleavage plane. Avoid making the incision close to the fallopian tube or fimbriae.
• Take the edges of the incision with two grasping forceps and strip out the cyst from the healthy ovarian parenchyma by delicate traction and counter traction maneuvers.
• After removal of the cyst, perform selective hemostasis with bipolar coagulation using the water test, mainly on the edges of the ovary, to reduce the risk of ovarian damage.
• At the end of the surgery, carefully remove the uterine manipulator if positioned. Suture the fascia with a medium absorption rate braided suture size 0 and the skin with a quick absorption rate suture size 3–0. Place patches on all the incisions and remove the urethral catheter the same day of the surgical procedure.

ONE-STEP CO₂ FIBER LASER VAPORIZATION

In this surgical approach, the “pseudo-capsule” is not removed but it is ablated with energies with little thermal spread. Among the several sources of energy investigated so far, CO₂ fiber laser has showed promising results in the treatment of endometrioma-associated infertility. After its validation by Kaplan and his colleagues in 1973,¹⁹ from the early 1980s to the 1990s Nezhat brothers et al. had optimized the use of CO₂ laser for laparoscopic treatment of endometriosis.²⁰ CO₂ lasers emit light at a wavelength of 10,600 nm that is absorbed strongly by water: radiant energy is converted to heat, instantly raising the temperature of tissue water to more than 100°C and thus vaporizing the target lesion. Compared with all available energy sources, CO₂ laser is highly selective and precise, has minimal depth of tissue penetration²¹ and produces little lateral thermal spread, lowering the risk of unintended thermal damage produced by non-visible larger necrosis and/or deep penetration.²² Furthermore, being used in a non-contact mode, CO₂ laser allows continuous visualization of the section plane between healthy and endometriosis affected tissue. These properties are of crucial importance when attempting to preserve the surrounding viable ovarian tissue. In addition, CO₂ laser simultaneously cauterizes bleeding tissue making hemostasis very effective without the risks of cautery. Historically CO₂ lasers used to be fixed to rigid instruments lending to ergonomic difficulties; however, newer technologies have allowed for a flexible fiber delivery system, overcoming past ergonomic challenges by providing flexibility, durability, and ease of use. Thanks to CO₂ fiber laser introduction, treatment of endometriotic cysts is now allowed even by non expert surgeons.

Surgical technique

• First, mobilize both adnexa to restore the normal anatomy of the pelvis. Then, by using an aspiration or irrigation device, drain the cyst contents and irrigate and inspect its inner wall. Take a biopsy of the cyst wall using scissors and send it for routine histological examination to confirm the diagnosis of endometriosis.
• Select the basic operation mode and set the device to fiber laser mode with the continuous wave and constant timed-exposure mode at a power density of 13–15 W13.
• Evert the cyst with grasping forceps in order to expose the inner cystic wall and completely vaporize the inner wall with a CO₂ fiber laser in a radial way starting from the center to the periphery, keeping the tip of the fiber at a distance of at least 1 cm from the cystic surface.
• Do not suture the ovary after vaporization. Carefully control any source of bleeding at the end of the procedure using the water test (i.e., washing the bleeding sites to visualize and achieve hemostasis selectively) or by slightly reducing the pneumoperitoneum.

PRACTICE RECOMMENDATIONS

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