Blood flow analysis of compressed nerve root after intravenous injection of lipo-prostaglandin E1

Prostaglandin E1 (PGE1) is a potent vasodilator as well as an inhibitor of platelet aggregation and has therefore attracted interest as a therapeutic drug for lumbar canal stenosis. However, investigations in the clinical setting have shown that PGE1 is effective in some patients but not in others, although the reason for this is unclear. The aim of the present study was to measure changes in intraradicular blood flow after intravenous injection of lipo-PGE1 (0.15 µg/kg) using a laser Doppler flow meter in control model and nerve root compression model. Then, the nerve root in which blood flow was measured was removed and examined histologically. Intravenous injection of lipo-PGE1 also resulted in marked increase of blood flow in the uncompressed nerve roots of the control group, but caused minimal enhancement of blood flow at the sites of nerve root compression exhibiting Wallerian degeneration. It is concluded that lipo-PGE1 has less effect on markedly degenerated nerve roots than it does on those that are normal. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res