[Experimental scoliosis in the rat spine induced by binding the spinous processes].

The effects of limitation of spinal mobility in forward flexion on the development of scoliosis was studied in experimental animals. The spinous processes of three lumbar vertebrae of young female rats were sutured together to make persistent limitation in the forward flexion of the spine. The lumbar vertebrae of rats, which normally are kyphotic in their profile, frequently became flattened or lordotic after the operation. Scoliosis with a primary curve at the sutured site was produced, although the curve magnitude was mild in 38% of 73 operated rats, and appeared more frequently in those which had more limitation in the spinal mobility at the sutured vertebrae than in those with less limitation. In histological examinations, the coronal sections of vertebral specimens of scoliotic animals demonstrated wedge-shaped intervertebral discs, deviation in the vertebral nucleus pulposus toward the convex side of scoliosis, and a degeneration in the annulus fibrosus. Thickening of the cartilaginous endplates on the convex side and a rupture in them on the concave side were observed in some of the animals. These findings indicated that the experimentally produced scoliosis was structural. This experimental study suggested that a limitation in the spinal mobility in forward flexion has a causative effect on the development and progress of idiopathic scoliosis.