Selective Blocking of the Anterior Branch of the Obturator Nerve in Children with Cerebral Palsy

Abstract

To evaluate the effect of selective blocking of the anterior branch of the obturator nerve by using phenol in controlling adductor spasticity in children with cerebral palsy. To study the anatomic location of the anterior branch of the obturator nerve with respect to bony landmarks in the inguinal area, 12 limbs of seven adult cadavers were anatomically dissected. We injected 22 anterior branches of obturator nerves in 11 children with spastic cerebral palsy with 5% aqueous phenol guided by anatomical landmarks and electrical stimulation. The range of motion (ROM) of hip abduction and the modified Ashworth scale (MAS) grade of the hip adductors were measured preinjection, and at 1, 3, 6, and 12 mos after injection. Successful clinical results (range of hip abduction greater than 45 degrees with the knee extended) were achieved in all the children immediately after the injection. The average volume of 5% aqueous phenol injected per nerve was 0.79 +/- 0.20 ml (0.12 +/- 0.02 ml/kg). The effect was maintained for more than 6 mos. No immediate or delayed complications were observed. Selective blocking of the anterior branch of the obturator nerve with 5% aqueous phenol can safely and effectively control adductor spasticity in children with cerebral palsy.