Psychosocial Determinants of Pain in Muscle Biopsy

INTRODUCTION/AIMS: Open muscle biopsy (OMB) is a key diagnostic tool for neuromuscular diseases, though patients often worry about risks and discomfort. This study aimed to assess pain during and after OMB, factors influencing pain perception, and adverse events. METHODS: In this single-center prospective study at the Neuropathology Unit of the Pitié-Salpêtrière Hospital, Paris, 100 patients (68 women; mean age 55.4 years) aged ≥ 18 years with suspected myopathy were enrolled from August 2024 to June 2025. Exclusion criteria were inability to understand French, pregnancy, and no social security coverage. Patients completed the numerical rating scale (NRS) for pain assessment and the Patient Health Questionnaire-9. Descriptive statistics summarized patient characteristics. Univariate and multivariate linear regression analyses identified factors associated with procedural pain. Follow-up phone calls were performed at 15 and 30 days postbiopsy. RESULTS: Procedural pain was mild (median NRS = 2) with moderate and weak positive correlations with preprocedural anxiety (r = 0.54, p < 0.01) and Clinical Frailty Scale scores (r = 0.32, p = 0.02), respectively. Weak negative correlations were observed with satisfaction with staff communication (r = -0.29, p = 0.02) and comfort with medical staff (r = -0.27, p = 0.05). Postprocedural discomfort occurred in 42/83 patients, mostly short-lived. No major complications occurred. DISCUSSION: OMB is a safe procedure. Pain intensity was lower than that generally reported in the literature. Frailty may influence acute pain perception. Preprocedural anxiety emerged as the strongest predictor of pain intensity. Therefore, preprocedural anxiety should be routinely addressed in patients undergoing OMB.