Electrophysiologic evidence for extremely late sensory collateral reinnervation in humans.

We present a patient in whom unexpectedly late sensory recovery occurred over 5 years after removal of a 3-cm piece of the right inferior alveolar nerve (IAN) in tumor surgery of the mandible. For a year after surgery, the distribution of the mental nerve, the terminal branch of the IAN, was totally anesthetic. Thereafter, a gradual subjective sensory recovery occurred centripetally from the surrounding skin distributions. Five years after surgery, findings in electrophysiologic tests were consistent with a total lesion of the right IAN. Two years later, electrophysiologic tests gave, for the first time in humans, objective evidence for sensory collateral sprouting in trigeminal distribution.