Vocal fold paralysis: improved adductor recovery by vincristine blockade of posterior cricoarytenoid.

OBJECTIVES/HYPOTHESIS A new treatment for acute unilateral vocal-fold paralysis (UVFP) was proposed in which a drug is injected into the posterior cricoarytenoid muscle (PCA) shortly after nerve injury, before the degree of natural recovery is known, to prevent antagonistic synkinetic reinnervation. This concept was tested in a series of canine experiments using vincristine as the blocking agent. STUDY DESIGN Animal experiments. METHODS Laryngeal adductor function was measured at baseline and at 6 months following experimental recurrent laryngeal nerve (RLN) injuries, including complete transection, crush injury, and cautery. In the treatment animals, the PCA was injected with vincristine at the time of RLN injury. RESULTS Adductor function in the vincristine-treated hemilarynges was significantly improved compared with injury-matched noninjected controls (total n = 43). Transection/repair controls recovered 56.1% of original adductor strength; vincristine-treated hemilarynges recovered to 73.1% (P = 0.002). Cautery injuries also improved with vincristine block (60.7% vs. 88.7%; P = 0.031). Crush injuries recovered well even without vincristine (104.8% vs. 111.2%; P = 0.35). CONCLUSION These findings support a new paradigm of early, preemptive blockade of the antagonist muscle (PCA) to improve ultimate net adductor strength, which could potentially improve functional recovery in many UVFP patients and avoid the need for medialization procedures. Possible clinical aspects of this new approach are discussed.