The additional yield of combined nerve/muscle biopsy in vasculitic neuropathy.

BACKGROUND: vasculitic neuropathy can be confirmed by demonstrating vasculitis in a nerve biopsy, but it is uncertain to what extent combined (i.e. nerve/muscle) biopsy improves the yield. METHODS: a random-effects meta-analysis was performed to assess the additional yield of combined biopsy in vasculitic neuropathy. Medline, Embase, LILACS and ISI were searched from January 1980 until January 2009 for relevant articles on the yield of nerve, muscle or combined biopsy to diagnose vasculitic neuropathy. Fourteen (15%) studies were included. Methodological quality was scored using a modified Quality Assessment for Diagnostic Accuracy Studies tool. RESULTS: in patients clinically suspected of vasculitic neuropathy, the additional yield of definite vasculitis in combined biopsy was 5.1% (95% CI 1.1-9.2%; P = 0.013). In patients diagnosed with vasculitic neuropathy, the additional yield of definite vasculitis in combined biopsy was 15% (95% CI 2.1-28%; P = 0.023). CONCLUSIONS: there is a modest additional yield of definite vasculitis in combined biopsy compared to nerve biopsy alone. Because of methodological flaws in analysed studies, the findings should be validated in a prospective study.