Percutaneous phenol blocks to motor points of spastic forearm muscles in head-injured adults.

The motor points of spastic wrist and finger flexors were identified using a nerve stimulator. These motor points were injected percutaneously with either a 3% or 5% aqueous solution of phenol in 11 patients with brain injury. The effectiveness of the blocks was assessed by recording the resting angle of the wrist, active extension of the wrist, and passive extension of the wrist--first with the fingers flexed and then with the fingers extended. The blocks were repeated once in two patients and twice in one patient for return of muscle tone which interfered with hand function. Relaxation of muscle tone persisted for up to two months following the injections. The resting angle of the wrist improved a mean of 25 degrees. Active wrist extension improved an average of 30 degrees. The changes in wrist measurements represent the effects of different processes: 1) the neurolytic effect of the phenol block; 2) improvement in the neurologic status of the patient; and 3) regeneration of the motor end plate. This procedure is an effective method of temporarily controlling spasticity and allowing functional hand training while neurologic recovery is occurring.