Impacts Of Radical Extracorporeal Shock Wave On Spinal Cord Applied To Thoracic Spine Area In Rabbits

Objective: To investigate the impacts of radical extracorporeal shock wave (rESWT)on thoracic spinal cord with intact lamina or laminectomy in rabbits.Methods: In this experiment,32rabbits were divided randomly into4groups. Ingroup SE,1000impulses with pressure of4bar (equivalent to0.55mJ/mm2energyflux density) of were applied to rabbits at the site of thoracic spinal process11(T11)7days after operation for laminectomy of T10-T11. In group E, the same rESWT as thatin group SE were applied to rabbits with intact lamina. In group S, rabbits underwenta laminectomy and no rESWT was used. In group N, rabbits received no operationand no rESWT.24hours after rESWT, rabbits were killed and segments of spinal cordequivalent to T10-T11spinal column were harvested and prepared for examination.Results: None of the rabbits in all groups, including the study groups (group E andgroup SE) showed weakness or paralysis of the hind limbs throughout the entire post-rESWT period. Of the spinal cord from all groups, the gross morphology showednormal surface appearance, and light microscopic examination was normal and foundno neuronal loss.On electron microscopic examination, the spinal cord from group SEshowed varying degrees of myelin and membranous structure of nerve cells damage.Immunohistochemical analysis indicated that the expression of synaptophysin inspinal cord from group SE decreased significantly compared to that in group E, groupS and group N.Conclusion: rESWT produced varying degrees of microscopic injuries to the spinalcord through the vulnerability of spine column lamina (laminectomy). The intactspinal lamina provided protective effect on the spinal cord from rESWT damageapplied to it.