Adenomyosis (uterine adenomyosis) is a common gynecological condition in which the endometrial glands and mesenchyme invade the myometrium to form diffuse or confined lesions. The treatment options for this disease are numerous, and clinical decisions need to be individualized, taking into account the patient’s symptoms, age, and fertility requirements, and are often combined with a combination of medications and surgery. The clinical features and treatment of adenomyosis, especially surgical procedures and indications, are summarized here to guide clinical treatment. Etiology Adenomyosis is caused by the invasion of the basal endometrium into the myometrium by endometriosis, and is closely related to the occurrence of multiple pregnancies and deliveries, abortions, and chronic endometritis. Secondly the relationship between hyperestrogenemia and uterine adenomyosis is striking. Pathology Ectopic endometrium grows diffusely in the myometrium, mostly involving the posterior wall, so that the uterus is uniformly enlarged, with a marked increase in anterior and posterior diameter and a spherical shape, usually not exceeding the size of the uterus at 12 weeks of gestation. The lesion is not clearly demarcated from the surrounding myometrium due to the proliferation of fibrous tissue around the lesion caused by recurrent local bleeding, which makes it difficult to peel off during surgery. The microscopic examination is characterized by the presence of ectopic endometrial glands and interstitium in an island-like distribution within the myometrium. Clinical manifestations The main symptoms are: 1. dysmenorrhea: more than half of the patients have secondary dysmenorrhea; 2. abnormal menstruation: excessive menstruation, prolonged menstruation or irregular bleeding; 3. infertility; 4. uterine enlargement: the uterus is uniformly enlarged or limited nodular bulge on gynecological examination, hard and painful, with significant pressure pain during menstruation. It may be combined with uterine fibroids and endometriosis. Diagnosis A preliminary diagnosis can be made based on symptoms, pelvic examination and the following ancillary tests: 1. Ultrasonography shows an enlarged uterus with a thickened myometrium, more pronounced in the posterior wall and an anterior shift of the endometrial line. The lesion is isoechoic or echogenically enhanced, with punctate hypoechogenicity seen in between, and no obvious boundary between the lesion and the surrounding area. MRI shows that there are poorly defined lesions with low signal intensity in the uterus, and T2-weighted images can have lesions with high signal intensity and a wider endometrium-myometrium binding zone with a width >12 mm. MRI has a more specific signal for adenomyosis, with a diagnostic accuracy of 100%. 3.Serum CA125 level can be increased in most cases, with a positive rate of 80%. 4. Pathological examination is the “gold standard” for diagnosis. The overall principle of treatment: the treatment plan should be individualized depending on the severity of the myelopathy, age and the requirement of fertility. 1. Expectant therapy: for asymptomatic patients without fertility requirements. For young patients who wish to keep their uterus, oral contraceptives or LNG-IUS should be used; for patients with significant uterine enlargement or severe pain symptoms, GnRH-a should be used for 3 to 6 months, followed by oral contraceptives or LNG-IUS. Follow-up. 3.Surgical treatment: (1) Radical surgery: Indications for hysterectomy and choice of route: If patients with adenomyosis do not have fertility requirements, and if the lesions are extensive, if conservative treatment is ineffective for severe symptoms, if there are combined fibroids or if there are risk factors for endometrial cancer such as family history, obesity, diabetes or polycystic ovary syndrome, hysterectomy is recommended. Total hysterectomy is preferred, and partial hysterectomy is generally not advocated. There are several reasons for this: ① residual cervical adenomyosis; ② inability to effectively remove coexisting endometriosis. More than half of the cases of adenomyosis are accompanied by endometriosis, and the foci of endometriosis are often located in the posterior part of the cervix and the uterosacral ligament. Partial hysterectomy results in residual endometriosis foci and persistence of postoperative painful symptoms because the cervix is preserved; (3) the possibility of cervical lesions. (2) conservative surgery: ① adenomyosis lesion excision: for young patients with fertility requirements. Preoperative MRI or ultrasound should be performed to clarify the lesion and its extent. Surgery requires removal of as much tissue as possible, which can significantly improve symptoms and increase the chance of pregnancy. However, most adenomyosis lesions are diffuse and poorly defined, making complete removal of the lesion very difficult. Excision of adenomyosis lesions alone does not provide significant pain relief. In patients with large uterine volume and anemia, preoperative application of GnRH-a can reduce uterine blood flow, reduce volume, and correct anemia, which can help the operation. Studies have reported that preoperative application of GnRH-a for 3 months can reduce uterine volume by 50.8%. Surgical points of adenomyosis lesion excision: remove as much of the lesion as possible, and judge whether the lesion is cleaned or not based on the appearance, texture and blood flow of the tissue. As the surgical incision is usually under greater tension, it is not easy to close. Therefore, if the incision is long and laparoscopic suturing is difficult, open surgery can be completed. Postoperative pain relief rate is low and recurrence rate is high after adenomyosis lesion excision alone. Therefore, effective adjunctive surgical methods should be sought. Surgery can be considered in terms of reducing uterine blood flow to shrink the lesion or blocking uterine nerve pathways to reduce nerve conduction of pain. Electrocoagulation of uterine lesions: The use of electrocoagulation of adenomyosis lesions can allow necrosis of the lesions and thus achieve treatment. However, it is difficult to judge whether electrocoagulation is complete. The lesions are replaced by scar tissue after electrocoagulation and the chance of uterine rupture in postoperative pregnancy is greatly increased. This option may be considered for patients over 40 years of age with extensive intramyocardial lesions that cannot be effectively resected, while the patient has no requirement for fertility but wishes to preserve the uterus. Surgical points for electrocoagulation of uterine lesions: if technically feasible, the superior branches of the uterine artery should be electrocoagulated; monopolar or bipolar electrocoagulation forceps should be applied to electrocoagulate the uterine lesion. Theoretically, bipolar electrocoagulation has less chance of heat transfer; the extent of electrocoagulation and can be controlled by reducing the intensity and duration of action of the current. Attention should be paid to the necrosis of the uterine surface tissue to avoid the formation of future adhesions; therefore, the insulated part of the electro-needle during the procedure should penetrate several millimeters below the uterine plasma membrane, and the depth of electro-needle penetration, spacing, and distance between bipolar electrodes should be controlled in an appropriate range. (iii) Endometrial resection: it is most suitable for the excision of lesions at the junction of endometrium and myometrium, or the management of lesions that invade the myometrium more superficially, which can effectively improve symptoms such as pain and excessive menstruation. After the operation, the patient’s menstrual flow is significantly reduced, and even amenorrhea and dysmenorrhea improve or disappear. This procedure has significant effect on patients with mild disease, but is ineffective in patients with moderate or severe disease. For lesions that infiltrate deeper into the myometrium, endometrial resection alone is less effective, and laparoscopic hysterectomy or electrocoagulation of myometrial lesions can be performed at the same time. For women without reproductive requirements, hysterectomy is recommended. The surgical points of endometrial resection: the endometrial resection includes the whole endometrium and the myometrium of 2-3 mm below the endometrium. Since most of the blood vessels in the myometrium are in the myometrium above 5 mm, excision of the myometrium too deeply can lead to bleeding and may result in amenorrhea or pelvic endometrial implantation. Laparoscopic uterine nerve ablation (UNA) and presacral neuromectomy (PSN): this procedure is currently considered to be one of the most effective means of treating pain, especially in women who strongly prefer to preserve the uterus. The sensory nerves of the uterus are accompanied by sympathetic and parasympathetic nerves, and blocking the access to these nerves may block the transmission of nerve impulse signals to the center for pain sensation, thus reducing symptoms. The surgical points of laparoscopic uterine nerve block and presacral nerve block: LUNA is a simpler procedure, whereas LPSN is a riskier procedure and requires more surgical skills. complications of LPSN include vascular injury, constipation, urinary symptoms, and celiac ascites. ⑤ Uterine artery embolization (UAE): Uterine artery embolization may be considered in cases of significant dysmenorrhea. Embolization is the main efficacy assessment criterion based on the improvement of clinical symptoms such as dysmenorrhea and menstrual flow. One study demonstrated that the medium and long-term clinical efficiency of vascular intervention for adenomyosis was 82.39%. Surgical points of uterine artery embolization: the target vessels of adenomyosis are the superior branches of the uterine arteries bilaterally. In order to improve the efficacy and to completely embolize the tiny vessels in and around the adenomyosis lesions, embolic agents of small diameter can be used. However, it should be noted that once the tiny embolic agents enter the endometrium, ovarian vascular network, and ureteral branches of the uterine artery they can lead to uterine amenorrhea, ovarian amenorrhea, and urinary tract injury. (6) High Intensity Focused Ultrasound (HIFU): It is suitable for patients with adenomyosis with predominantly dysmenorrhea and a single uterine wall thickness ≥ 30 mm. The principle of HIFU is to use the penetrability, energy deposition and focusability of ultrasound in the tissue to gather ultrasound emission outside the body on the target tissue and convert the sound energy into heat energy, so that the temperature in the target tissue will rise rapidly to 60-100℃, and achieve the therapeutic effect by coagulative necrosis of the target tissue through high heat effect, mechanical effect, cavitation effect and immune effect. The key points of high-intensity focused ultrasound ablation: For women with fertility requirements, attention should be paid to protect the endothelium, so that the focus is 15 mm away from the endothelium, or even give up treating lesions close to the endothelium. 4. Treatment of combined infertility For patients with adenomyosis who have fertility requirements, pharmacological treatment (GnRH-a) or conservative surgery plus pharmacological treatment followed by active treatment with assisted reproductive technology can be chosen. The risk of uterine rupture in pregnancy after conservative surgery should be noted. For those without fertility requirements, medication for long-term symptom control or conservative surgery plus medication may be chosen, or the uterus may be removed. In conclusion, adenomyosis is an important factor leading to dysmenorrhea, excessive menstrual flow and infertility, and pathological diagnosis is the gold standard. There is a gradual increase in the incidence of adenomyosis, and its treatment is becoming increasingly diversified. The risk of uterine rupture in pregnancy after conservative treatment of adenomyosis is greater than that of myomectomy. After myomectomy, there is no significant loss of myometrium after suturing of a normal uterus. In contrast, the adenomyosis lesion invades within the normal myometrium and the excision of the lesion also leads to the absence of part of the normal myometrium, with the following consequences: reduction in the volume of the myometrium during pregnancy leading to miscarriage and preterm delivery; scarring of the uterine wall after surgery and the remaining adenomyosis lesion within the myometrium, which affects the tone and strength of the uterus; increased tension and difficulty in the closure of the incision after surgery due to the absence of the myometrium around the lesion, leading to weakness of the wall of the spotted uterus. Therefore, when choosing conservative lesion excision or electrocoagulation in patients with adenomyosis with fertility requirements, it is important to consider the severity of the patient’s condition and weigh the pros and cons of various treatments. Therefore, the choice of treatment should be individualized based on the patient’s age, fertility requirements, severity of clinical symptoms, location and extent of lesions, and the patient’s wishes.