Pathophysiology, diagnosis and treatment of intermittent claudication in patients with lumbar canal stenosis

Figure 10 Effect of prostaglandin E₁ on normal (A-C) and compressed nerve root (D-F). The seventh lumbar nerve root was clamped with a clip for 3 wk using dogs. After release of clipping, the intraradicular blood flow was measured before and after intravenous injection of lipo-prostaglandin E₁ (PGE₁) (D-F). As the control group, animals were evaluated at 3 wk after laminectomy. The nerve root was only exposed and wasn’t clamped with a clip (A-C). In the control (A) group, the mean blood pressure fell immediately after intravenous injection of lipo-PGE₁ due to the peripheral vasodilation, but then gradually increased and recovered after 20 min. The changes of blood pressure in the nerve root compression group were the same as those seen in the control group (D). Intravenous injection of lipo-PGE₁ also resulted in marked increase of blood flow in the normal nerve roots (B), but caused minimal enhancement of blood flow at the sites of nerve root compression exhibiting Wallerian degeneration (E). Histological examination revealed no degeneration of the nerve fibers in the control group (C). However, marked Wallerian degeneration was seen in the nerve root compression group (D). The relative number of small diameter axons increased in the compression group at 3 wk after operation compared with the control group (HE stain, original magnification X 50).