Efficacy and safety of ultrasound-guided needle muscle biopsy in the diagnosis of idiopathic inflammatory myopathies.

Abstract

We aimed to assess the safety and efficacy of ultrasound-guided needle muscle biopsy (UGNMB) using a 14G biopsy needle in obtaining adequate samples for histological analysis and establishing an inflammatory idiopathic myopathy (IIM) diagnosis in patients with suspected myositis. We included patients who were followed up at our Rheumatology Department with a suspected IIM diagnosis. UGNMBs were performed from January 2022 to April 2024. Ultrasound was used to select which muscle to biopsy, to guide the anaesthesia and the muscle sample retrieval using a 14G guillotine-type semiautomatic biopsy needle. Forty-four biopsies were performed, half in female patients (n = 22). Nearly 90% (n = 40) of the samples allowed a thorough histologic evaluation. Almost one-third of the samples (n = 12) were compatible with myositis, 27.2% (n = 12) of the biopsies showed nonspecific muscle changes and the remaining revealed muscle tissue without pathological changes. More than half of the patients (30/44) had a histological result that matched the final clinical diagnosis. The UGNMB was generally well-tolerated, with an average Visual Analogical Scale (VAS) for pain of 3.8 out of 10 during the procedure. No moderate or severe adverse events were reported. Histological analysis was possible in most samples, suggesting that UGNMB is an effective way to collect muscle samples for IIM differential diagnosis. UGNMB also seems to be a safe method for collecting muscle samples.