Endometriosis is generally considered a benign gynecologic disorder, while it may be accompanied by malignant ovarian tumors(1) or may cause severe complications, such as pelvic pain, dysmenorrhea, and infertility (2). Endometriosis has been reported in about 10% of women of reproductive age; however, several cases may remain undiagnosed, as it does not have any pathognomonic sign/symptom (3), and clinical characteristics can only help predict endometriosis (4).
However, the exact etiology of endometriosis is still unclear. A combination of genetic, familial, and environmental factors has been suggested as the pathophysiology of endometriosis (5). Retrograde menstruation during endometriosis was suggested as the most commonly accepted etiology that can cause inflammatory and immune responses in the peritoneum and other sites (6). A study on animal models suggested altered lipid metabolism as one of the reactions to peritoneal inflammation (7). Clinical studies have also confirmed unfavorable lipid profiles, especially higher levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) levels in women with endometriosis (8, 9), associated with the increased risk of coronary heart disease (CHD) in women with endometriosis (10).
Furthermore, statins have been suggested as novel endometriosis treatments, which can reduce patients' pain and other symptoms, possibly by reducing inflammation and apoptotic activities (11, 12). Accordingly, it seems that endometriosis has a shared mechanism with an unfavorable lipid profile; but some other researchers have rejected such an association (9, 13). Another important finding in women with endometriosis is the lower serum level of 25–hydroxyl vitamin D (25(OH)D), suggested to be associated with the dysregulated immunity during endometriosis (14). Furthermore, supplementation with 25(OH)D modulates inflammation and proliferation in endometriotic cells and serves as a novel treatment for endometriosis (15, 16). As far as we are concerned, although the effect of laparoscopic resection of endometriosis has been confirmed on pain and clinical symptoms of the patients with endometriosis (17), its impact on the serum levels of lipids and 25(OH)D has not been studied previously. According to the importance of serum lipid profiles in CHD and 25(OH)D in immunity, it is worth studying whether the laparoscopic resection of endometriosis can correct these disorders in women with endometriosis or not. Therefore, the present study aimed to evaluate the effect of radical laparoscopic surgery of endometriosis on serum levels of lipid profile and 25(OH)D.

 

Study Design

This cross-sectional study included all women aged 15 to 45 who were referred to the Gynecology Department of General and Referral Shohaday-e Tajrish Hospital affiliated with the Shahid Beheshti University of Medical Sciences, from May 2018 until Jan 2020, for the surgical treatment of endometriosis. Exclusion criteria were patients with thyroid disorders, current pregnancy, women with a history of systemic diseases (diabetes and hypertension), women with body mass index (BMI)>30 kg/m², women who used alcohol or smoked, and those who used oral contraceptives and/or other hormonal therapies three months before surgery. The eligible patients were enrolled in the study voluntarily and by the census method. This study was approved by the Medical Ethics Committee of the Shahid Beheshti University of Medical Sciences (code: IR.SBMU.RETCH.REC.1398.104). The patients were recommended not to change their diet after surgery.
The following information was collected from medical records, interviewing the patients, and physical examination and recorded in the study checklist: patients' age, weight, age at marriage, number of pregnancies, abortions, live births, and children numbers, endometriosis symptoms, and family history of endometriosis and pelvic infection. The severity of the participants' pelvic pain, dyspareunia, and dyschezia was evaluated using a 10–point visual analog scale (VAS), and the participant was asked to indicate the pain severity from 0 (fewer) to 10 (the highest) on this scale.
All participants had regular and similar diets before and after surgery. On the day of admission and after 12 hours of fasting, the patient was sent to the hospital laboratory. One blood sample (5 mL) was taken from the participant's left cubital vein in the sitting position, collected in two clots activator tubes, and kept at room temperature. The first tube was used for the analysis of the lipid profile. For this purpose, after about 15 minutes, the samples were centrifuged at 4000 RPM to separate serum. The sera were transferred to an Auto Analyzer (Kitachi, Model No. 917), which works by photometry. The Pars Azmoon kits (Iran) were used for the analysis, with the following normal ranges: TG 50–250 mg/dL, TC<120–130 mg/dL, HDL≥35 mg/dL, and LDL≤ 100 mg/dL. For the measurement of 25(OH)D levels, blood samples were centrifuged at 3500 RPM for 20–30 minutes for the separation of serum. The sera were analyzed right after centrifugation or kept at -20°C freezer until the next day. After the samples reached the room temperature, Statfax device Model No. 2000 was used for performing enzyme-linked immunosorbent assay (ELISA), using an Ideal kit (Iran) with the following range: deficient <20 mg/dL, insufficient 20–29 mg/dL, sufficient 30–100 mg/dL, and potential toxicity >100 mg/dL.
After bowel preparation and prophylaxis of thromboembolism, and insertion of ureteral stent (where needed), the patients underwent radical laparoscopic treatment of endometriosis by one gynecologic surgeon using Karl Storz Laparoscopy device (Tuttlingen, Germany). For the surgery, the patient was laid in the lithotomic position. After entering the abdomen, an exploration of the abdomen and pelvis was performed to detect endometriotic lesions and their characteristics (penetration). All the pelvic organs, such as uterosacral, round ligament, peritoneum, and sigmoid colon, were evaluated. Appendicitis and extrapelvic sections were evaluated for the presence of endometriotic lesions. Based on the patient's stage and positive findings, the ovarian adhesions were released, and the endometriotic lesions were resected or ablated. Cystectomy was performed in case of the presence of endometrioma, and the ovaries and uterus were suspended. After releasing the ureters and detection of the hypogastric nerve, the deep lesions below the ovarian fossa and uterosacral area and the deep endometriotic lesions of the rectum and bowel were excised using the shave method or discoid/segmental resection and anastomosis, based on the penetration, size, and location detected before surgery using physical examination, magnetic resonance imaging, and transvaginal/transanal Doppler ultrasound. After cystostomy, the lesions were excised and repaired in cases with the deep involvement of the bladder. Omentum, appendix, and diaphragm were also evaluated, and in case of involvement, the lesions were excised by omentectomy, appendectomy, and resection/ablation of lesions. In cases with an indication of hysterectomy, oophorectomy, or salpingectomy, these procedures were simultaneously performed. Deep lesions involving large pelvic vessels or nerves were shaved or resected.
Any participant who performed the postsurgical serum test earlier than two months was excluded from the study. The study's sample size was calculated at 47, considering α error of 0.05 and β of 0.85, but larger sample size was included, considering the risk of loss to follow–up.
 

 
Finally, 73 patients were evaluated, ten patients did not refer for the postsurgical follow–up, and 16 performed the second blood sample examination earlier than two months after surgery and were thus excluded from the study, resulting in analyzing the data of 47 patients. The mean ± SD of the participants' age was 32.8 ± 7.5 (20–45) years and the age at marriage was 22.8 ± 3.7 (14–45) years.
Statistical Analysis

For the statistical analysis, SPSS Statistical Software version 21.0 (SPSS Inc., Chicago, IL., USA) was used. The results were described by mean ± standard deviation (SD) and frequency (percentage), and compared between the two intervals (before and after) using paired t-test. The normal distribution of the numeric variables was previously confirmed by the results of the Kolmogorov Smirnov test. P-values<0.05 were considered statistically significant.