An experimental study in chickens for the pathogenesis of idiopathic scoliosis.

Experimentally induced scoliosis was investigated in pinealectomized chickens using pathologic and neurophysiologic means. A total of 90 chickens were tested; 30 served as a normal control, 30 received an autografted pineal body in the intramuscular tissue of the trunk, and 30 underwent pinealectomy without autograft. Scoliosis developed in all pinealectomized chickens within 2 weeks, showing gradual progression during the next 5 or 6 weeks. At 3 months, the three-dimensional spinal deformity consisted of lateral curvature and vertebral body rotation, resulting in a prominent lordoscoliosis at the thoracic level. In contrast, scoliosis developed in only 10% of the autografted chickens. Histologic examination revealed no pathologic change in the brain in either the pinealectomized scoliosis group or in the autografted nonscoliosis group. Cortical potentials in the scoliosis group were delayed, thus suggesting conduction disturbance rostral to the brain stem. Although the relationship between the cause and effect is uncertain, these findings implicate neurotransmitters or neurohormonal systems in the pineal body as a major contributing factor in this type of experimental scoliosis.