Clinical Outcomes After Whole and Fascicular Sural Nerve Biopsies: A Retrospective Review

Background Diagnostic sural nerve biopsies can be taken as whole or fascicular nerve biopsies. It is unclear if this is associated with differences in diagnostic yield or procedural complications. We compared the clinical outcomes of fascicular versus whole sural nerve biopsies. Methods This was a retrospective chart review of sural nerve biopsies performed between 2011 and 2024 at 4 tertiary academic hospitals in Canada. The primary outcome was the incidence of postoperative nerve-related complications. The secondary outcome was the concordance between the biopsy and the final diagnosis. Fisher's exact test was used to compare the incidence of postoperative complications. Two-sided Cochran-Armitage trend test was used to compare concordance between groups. Results There were 75 patients who underwent whole sural nerve biopsies and 13 patients who underwent fascicular sural nerve biopsies; 54.6% of patients were male, with a mean age of 59.7 ± 15.9. The average nerve length sampled was 2.86 ± 1.3 cm in the whole nerve biopsy group and 2.35 ± 1.3 cm in the fascicular nerve biopsy group. Only a small proportion of patients had documented follow-up (whole: 26.7%; fascicular: 15.4%), among whom 40.0% in the whole nerve biopsy group and 0.0% in the fascicular group experienced complications ( P = 1.00). The most common diagnosis was vasculitis in both groups (whole nerve biopsy: 17.0%, fascicular nerve biopsy: 36.4%). There was no statistically significant shift toward higher concordance in the whole nerve group (Z = 0.63, P = .53). Conclusion Fascicular and whole sural nerve biopsies demonstrated similar diagnostic concordance. Prospective studies with larger sample sizes are needed to more accurately characterize postoperative complication rates.