Clinical Effects of Posterior Tibial Nerve Block with Diluted Phenol Solution

Kim, Kweon Yeong

Abstract

The posterior tibial nerve was partially blocked with 7% phenol solutions for the relief of severe spasticity in cerebral palsy and brain injured patients. Forty patients were included in this study. Among them thirty five patients were cerebral palsy and five patients were brain injured. A phenol injection was performed to the posterior tibial nerve at the popliteal fossa with the patients in a prone position. Total injected dose in each patient was 0.40 to 4.00 cc (average 2.06 0.96 cc). The dose was far below the toxic level and no significant side effects were noted except for a few cases of local paresthesia and tenderness. The range of dorsiflexion of the ankle was increased and the gait pattern improved in most of the patients one month after the injection. The H-reflex latency was prolonged after the injection compared with the pre-injection latency. The phenol injection can greatly facilitate the rehabilitation process of the patient by reducing the need for physical therapy and bracing, increasing the patient's ambulation ability, and decreasing the development of secondary leg deformities. In conclusion, with the easiness, simplicity, safety, low cost, and a selective reduction of spasticity in the group of muscles, the remarkable therapeutic benefits of posterior tibial nerve blocked with 7% phenol solutions warrant the more widespread use of this technique in younger cerebral palsy patients before developing fixed soft tissue contractures.