Changes of the cell bodies in the facial nucleus after facial nerve block.

Facial nerve blocks were produced in four monkeys by insertion of a needle into the facial nerve trunk. The sequential changes of nerve cells in the facial nucleus were investigated 4 days, and 2 and 7 months later. Although the facial paralysis recovered in 2 months, considerable changes of cell bodies in the facial nucleus were still obvious which recovered completely only after 7 months. It is postulated that an optimum discharge is generated by those nerve cells in the facial nucleus during the recovery period which in clinical practice could result in 6 months of clinical remission from facial spasm.