A novel technique to identify the nerve of origin in head and neck schwannomas.

OBJECTIVE

Identifying the nerve of origin in head and neck schwannomas is a diagnostic challenge. Surgical management leads to a risk of permanent deficit. Accurate identification of the nerve would improve operative planning and patient counselling.

METHODS

Three patients with head and neck schwannomas underwent a diagnostic procedure hypothesised to identify the nerve of origin. The masses were infiltrated with 1 per cent lidocaine solution, and the patients were observed for neurological deficits.

RESULTS

All three patients experienced temporary loss of nerve function after lidocaine injection. Facial nerve palsy, voice changes with documented unilateral same-side vocal fold paralysis, and numbness in the distribution of the maxillary nerve (V2), respectively, led to a likely identification of the nerve of origin.

CONCLUSION

Injection of lidocaine into a schwannoma is a safe, in-office procedure that produces a temporary nerve deficit, which may enable accurate identification of the nerve of origin of a schwannoma. Identifying the nerve of origin enhances operative planning and patient counselling.