Anatomical Location of the Bifurcation of the Sciatic Nerve in the Posterior Thigh in Infants and Children: A Formula Derived From MRI Imaging for Nerve Localization

Background and Objectives: Sciatic nerve block is performed at the popliteal fossa for various surgical procedures in infants and children. The aim of this study is to review magnetic resonance imaging scans in children of various ages to assess the location of the division of the nerve in the posterior thigh. Methods: After Institutional Review Board approval was obtained, measurements of the bifurcation of the sciatic nerve in the posterior thigh were recorded from magnetic resonance images that were previously obtained in children of various ages. Data were recorded in a database and parametric and nonparametric statistical analysis was performed. Results: Measurements were recorded from 59 patient images. Using a linear regression model, we were able to arrive at a formula for determining the point of bifurcation of the sciatic nerve at the posterior thigh. The mathematical formula derived from the linear regression equation was:Distance of the sciatic nerve division cephalad to the popliteal crease (mm) = 27 + 4 ṡ age (y) . Conclusions: We speculate that this knowledge will assist practitioners who use nerve stimulation techniques for sciatic nerve blocks in children of all ages.