The facial nerve in 24 rats was exposed unilaterally and subjected to one of four procedures: (1) transection; (2) freezing with the cryoprobe; (3) tumor implantation without treatment; or (4) tumor implantation with subsequent freezing of tumor.
Transection produced facial paralysis without return of function. Freezing of the nerve and freezing of tumor implanted on the nerve produced temporary paralysis with return of function in three weeks. Implantation of tumor and subsequent growth of untreated tumor did not impair function of the nerve. All tumors not treated by cryosurgery were widespread within one month. All tumors treated by cryosurgery were destroyed within 35 days.