Abstract
Background Optimizing axon count is essential for successful nerve transfer surgery, and a donor-to-recipient
axon count ratio greater than 0.7:1 has been associated with improved outcomes. A
gracilis free functioning muscle transfer (FFMT) is an option to restore elbow flexion,
but its axon count has not been evaluated. Our aim was to quantify the axon count
of the nerve to the gracilis muscle.
Methods The nerve to the gracilis was dissected in 10 fresh frozen adult cadaveric hindquarter
specimens (four females and six males). The length of the nerve to the gracilis was
measured and a biopsy taken. A validated histologic preparation technique was utilized,
and axons were counted. The mean length and axon counts were calculated.
Results The average axon count in the nerve to the gracilis was 818 (range = 684–1,000, standard
deviation [SD] = 116). The average length was 98 mm (range = 81–115 mm, SD = 13 mm).
Conclusion Our study found the average axon count in the nerve to the gracilis was 818. Prior
literature suggests axon count ratio greater than 0.7:1 is associated with better
clinical outcomes. Using data from prior studies, the spinal accessory, three intercostal,
and two intercostal nerves are all sufficient for the transfer to the nerve to the
gracilis with donor to recipient ratios of 1.7:1, 1.3:1, and 0.9:1, respectively.
Keywords axon count - free functional muscle transfer - gracilis
