Patients
Between July 2014 and July 2020, 167 patients with adenomyosis were treated at Zhongshan City People’s Hospital and were enrolled in this study. The diagnosis of adenomyosis was confirmed using preprocedural MRI. All patients signed an informed consent form before HIFU treatment. Patients were divided into two groups according to the patients’ aspirations: the control group (group A), only adenomyosis lesions ablated with HIFU, and treatment group (group B), adenomyosis lesions and endometrial ablation with HIFU. Patients undergoing endometrial ablation were likely to develop infertility; therefore, they were fully informed, and consent was obtained before joining the treatment group. Patients who wished to preserve fertility were assigned to group A.
The inclusion criteria were as follows: premenopausal adult women (age > 18 years) presenting with clinical symptoms of dysmenorrhea and/or menorrhagia and agreed to undergo periodic checkups. The exclusion criteria were clinical examination or ultrasonography findings showing endometrial disease, pelvic endometriosis, or other uncontrolled systemic diseases and menstruation, pregnancy, or lactation.
HIFU ablation
HIFU was performed using an ultrasound-guided HIFU system (USgHIFU;JC200; Haifu Medical Technology Co., Ltd., Chongqing, China). The patients were preoperatively administered fentanyl and midazolam for sedation and analgesia. They were placed in the prone position on the HIFU treatment table to enable their skin to be in full contact with degassed water. A degassed water balloon was placed between the transducer and anterior abdominal wall to compress or push away the bowel. The treatment started from the center of the lesion as point sonication. The sonication power ranged from 350 to 400 W. During the procedure, the treatment area and sonication intensity were adjusted based on changes in the gray scale on ultrasound and patient tolerance. During treatment, patients were requested to lie still and report any discomfort, including burning of the skin or lower abdominal, leg, sciatic, and buttock pain.[5]
Post-treatment examination
All patients underwent MRI after HIFU to define the condition of the endometrium and evaluate the non-perfused volume (NPV). The volume of adenomyotic lesions and NPV were measured using the following equation for the prolate ellipsoid:[6] volume = 0.5233 *a *b *c (a, b, c are the longitudinal, anteroposterior, and transverse dimensions, respectively). The volume of adenomyotic lesions was defined as the volume of the part of the uterus where the focal adenomyotic lesions were located (Figure 1). The volume of the ablation lesions was defined as the volume of the non-perfused area (Figure 2). The NPV ratio (NPVR) was defined as the NPV divided by the lesion volume, NPVR = NPV/volume of the adenomyotic lesion × 100%. Successful treatment[7] with HIFU was defined as an NPV of ≥1 cm3 in the planned ablation zone.
The endometrium of the uterine cavity is an inverted triangle, and the uterine cavity has two sides. The area of the endometrium was measured using the following equation: area = 0.5*a × b (a and b are the longitudinal and transverse dimension, respectively) × 2. The measurements of the area of the intact endometrium and ablated endometrium were based on preoperative (Figure 3) and postoperative MRI findings (Figure 4), respectively. The ablation rate was defined as the area of frustrated endometrium divided by the area of endometrium ablation rate = (area of frustrated endometrium / area of endometrium) × 100%. Successful treatment with HIFU was determined as the occurrence of a destruction rate of ≥25%.
This study was approved by the Ethics Clerk Association of Zhongshan City People’s Hospital, all experiments were performed in accordance with relevant guidelines and regulations.
Evaluation of clinical symptoms after treatment
All adverse events and complications were recorded by a nurse during and after the procedure to examine the safety of HIFU. Follow-ups were performed by staff via telephone to register all post-surgical symptoms and complaints. There were two main observation indicators: dysmenorrhea and menstrual volume. The intensity of dysmenorrhea was assessed using a visual analog scale (VAS) score ranging from 0 to 10.[8] Menstrual volumes were scored according to patients’ descriptions of pictorial blood assessment chart methods（PBAC）.[9] The remission rate and clinical effectiveness were evaluated at 3, 6, and 12 months after HIFU ablation.
The reduced dysmenorrhea and menstrual volume scores before and after treatment, subtracted from the preoperative score by the postoperative score, were compared to determine whether the symptoms had alleviated. Symptoms were considered alleviated using the following criteria: (1) inefficient, with score reduction of 20%; (2) partial relief, with score reduction of 20%–50%; (3) significant relief, with score reduction of 50%–80%; and (4) complete relief, with score reduction of 80%. Clinical relief included partial, significant, and complete relief.[10-12]
Statistical analysis
Data are presented as mean ± standard deviation. SPSS (SPSSAU) was used for data analysis. The t-test was performed to compare the variables between the two groups. Statistical significance was set at a p-value of <0.05.