BACKGROUND: Ultrasound-guided anhydrous ethanol sclerotherapy (UGAES) is an effective treatment option for ovarian endometrioma-related pain and infertility. However, its use is limited by the fact that alcohol can sometimes cause unbearable abdominal pain. This study aimed to use different concentrations of lidocaine solution for cystic cavity flushing to assess its pain-relieving effect, and to investigate its effect on treatment efficacy and the degree of improvement in clinical symptoms. METHODS: This retrospective cohort study included 90 patients who underwent UGAES of ovarian endometriosis cysts from January 2022 to June 2024 at Zhejiang Hospital. The patients were allocated to the lidocaine group (comprising 61 patients) and the non-lidocaine group (comprising 29 patients) based on the use of lidocaine. The lidocaine group was further subdivided into four subgroups of 0.25%, 0.33%, 0.50%, and 1.00% depending on the concentration of lidocaine. Intraoperative pain scores (IPSs) were assessed by visual analogue scoring. At the three-month follow-up, the degree of improvement in clinical symptoms was assessed using the Clinical Symptom Scores (CSSs), and efficacy was assessed by repeat ultrasonography to calculate the cyst volume reduction ratio (VRR). RESULTS: A total of 90 cysts were collected from 90 patients (mean age: 29.50±6.58 years
range, 18-47 years). The patients in the lidocaine group had significantly lower IPSs than those in the non-lidocaine group [2 (IQR, 2, 3) CONCLUSIONS: The use of lidocaine in the intracavitary irrigation of cysts effectively reduces patients' intraoperative pain during UGAES. Different dilution concentrations of lidocaine did not have a significant effect on the therapeutic efficacy. These findings provide a new clinical strategy for pain management and may contribute to the improvement of patients' treatment experience.