Comparison of direct versus hysteroscopy-assisted levonorgestrel intrauterine system placement after high-intensity focused ultrasound ablation for adenomyosis: a retrospective cohort study

Purpose To compare LNG-IUS stability, clinical outcomes, and safety after direct versus hysteroscopy-assisted placement following high-intensity focused ultrasound (HIFU) ablation for adenomyosis.Materials and methods This single-center retrospective cohort study included 229 premenopausal patients with adenomyosis who underwent HIFU ablation and attempted LNG-IUS placement (direct, n = 135; hysteroscopy-assisted, n = 94). Post-placement outcomes were evaluated among patients with successful first-attempt placement and included LNG-IUS-related events, treatment continuation, symptom scores, lesion volume, and adverse events. Event-free survival was analyzed using Kaplan–Meier and Cox regression, with propensity score matching as a sensitivity analysis.Results First-attempt placement succeeded in 135 of 135 direct and 91 of 94 hysteroscopy-assisted patients. LNG-IUS-related events were less frequent with hysteroscopy-assisted placement (7.69% vs. 25.93%; p < 0.001), and treatment continuation at last follow-up was higher (92.31% vs. 74.07%; p < 0.001). Event risk remained lower with hysteroscopy-assisted placement before and after adjustment (HR = 0.393, 95% CI 0.173–0.891, p = 0.025; adjusted HR = 0.396, 95% CI 0.158–0.996, p = 0.049). Propensity score matching showed a similar but less precise association (HR = 0.265, 95% CI 0.070–1.002; p = 0.050). Symptom scores and lesion volume decreased in both groups, with no significant between-group difference in adverse events.Conclusions Hysteroscopy-assisted LNG-IUS placement after HIFU may be associated with fewer displacement or expulsion events and a higher rate of treatment continuation than direct placement. Symptom improvement and recorded adverse events were similar between groups. It may be considered for selected patients with suspected residual intrauterine necrotic tissue or unfavorable uterine cavity conditions.