Indication for pediatric muscle biopsy determines usefulness

Purpose: Diagnostic skeletal muscle biopsy is an invasive procedure used for evaluation of neuromuscular disorders. We hypothesize that the yield of biopsy varies with its indication or suspected diagnosis. Methods: Retrospective review of all muscle biopsies was performed at an academic tertiary care center between January 1, 1996, and August 1, 2006. Results: A total of 142 muscle biopsies were performed on 127 children. Mean age at biopsy was 5.3 years (median, 3.3; range, 8 days-21 years) with 48% female. Follow-up was maintained for a mean 3.4 years (median, 2.2; range, 1 month-10.4 years). Specific pathological diagnoses were obtained from 33 (23%) of 142. Changes in therapy resulted from 11 (8%) of 142 biopsies. Treatment changed for all patients with prebiopsy suspicion of inflammatory or neoplastic processes (7/7, 100%); these accounted for 7 (64%) of 11 patients with treatment changes. Thirteen patients underwent multiple biopsies, with 1 (8%) patient's treatment adjusted as a result. Fifteen neonates (<100 days) underwent a total of 17 biopsies; none changed treatment plans. Conclusions: Muscle biopsy for neuromuscular disorders is inconsistently useful. Specific diagnoses are occasionally revealed, but treatment changes are infrequent except in those patients with suspected neoplastic or inflammatory disease. Ongoing study is required to determine the most rational indications for this procedure.