Axonal numbers in the greater auricular nerve: is there enough to go round?

Hypothesis: Does the greater auricular nerve (GAN) have an appropriate number of myelinated axons for use as an interposition graft for the facial nerve?

Background: Previous studies have suggested that the GAN has a suitable cross-sectional and fascicular area for use as an interposition graft for the facial nerve. In this study, counts of myelinated axons in the GAN have been undertaken to assess, at a microscopic level, its suitability as such a graft.

Methods: Six GANs were examined, and the total myelinated axonal counts and axonal density per square millimeter of fascicular area were calculated. These counts were compared with previous studies on the facial nerve.

Results: Axonal density per square millimeter was comparable between greater auricular and facial nerves. However, there were significantly lower numbers of myelinated axons in the GAN compared with the published facial nerve data.

Conclusion: The findings support the concept of "doubling over" the GAN to act as an appropriate interpositional facial nerve graft when there is a size mismatch between the two.