Fixation techniques for the Levonorgestrel-Releasing Intrauterine system in adenomyosis: a narrative review

BACKGROUND: Adenomyosis causes severe dysmenorrhoea and menorrhagia. While the Levonorgestrel-Releasing Intrauterine System (LNG-IUS) is a highly effective conservative treatment, its success is frequently compromised by high expulsion rates (15%-37.5%) caused by uterine enlargement and cavity distortion. This review evaluates the principles, clinical efficacy, and safety of emerging intrauterine fixation techniques designed to prevent LNG-IUS downward displacement and expulsion. METHODS: A comprehensive literature search was conducted across PubMed, Web of Science, and Google Scholar for articles published between January 2000 and February 2026. The review synthesised data from observational studies, retrospective cohorts, and controlled trials focusing on the surgical modification and stabilisation of the LNG-IUS in patients with adenomyosis. RESULTS: Current intrauterine fixation strategies are broadly classified into hysteroscopic suture fixation (utilising non-absorbable sutures to anchor the device to the myometrium) and non-suture fixation (encompassing combined frameless IUD fixation, device-modified anchoring, and direct tail-embedding). Current literature indicates that these techniques significantly reduced expulsion rates, generally to below 7%, compared to conventional placement failure rates that can exceed 30%. This mechanical stabilisation maintains the device's pharmacological efficacy, yielding sustained improvements in dysmenorrhoea and reducing menstrual blood loss. Nonetheless, these procedures introduce new clinical and safety challenges. Key concerns include off-label regulatory issues regarding manual device modification, altered sonographic imaging profiles, increased removal complexity requiring secondary hysteroscopic intervention, and theoretical long-term risks associated with myometrial micro-scars. CONCLUSION: Intrauterine fixation significantly mitigates LNG-IUS expulsion in adenomyosis. While highly effective, the manual and invasive nature of these techniques necessitates careful patient selection and rigorous safety monitoring. Future research must prioritise large-scale randomised controlled trials. Ultimately, clinical practice should transition from manual surgical modifications towards the standardised industrial development of next-generation LNG-IUS devices equipped with inherent anti-expulsion features.