Straight leg raising test versus radiologic size, shape, and position of lumbar disc hernias.

In 30 patients with a computed tomography-verified lumbar disc herniation, the relation between the straight leg raising test and the size, shape, and position of the hernia was evaluated before, 3, and 24 months after inception of nonoperative treatment. Hernia size was expressed as an index relating it to the size of the spinal canal. The limitation of the straight leg raising test was not related to size or position of the hernia. Before treatment, straight leg raising was equally restricted in patients with sharply pointed or blunt hernias, but after 3 months straight leg raising was less limited in patients with sharply pointed hernias, whereas after 24 months straight leg raising was regularly normalized. Size index was lower for sharply pointed hernias at all three computed tomography scans. A decrease in hernia size over time, irrespective of shape, was not correlated to a concomitant improvement in straight leg raising. It must be presumed that additional factors, such as inflammatory reactions affecting the nerve roots, are of importance for the magnitude of straight leg raising.