Effect of intrathecal papaverine on blood flow and secondary injury in injured cord.

ABSTRACT

STUDY DESIGN: Experimental laboratory investigations with a model of neurotrauma in Macaca rhesus. OBJECT The present study evaluates whether intrathecal papaverine induces changes in spinal cord blood flow (SCBF) of injured spinal cord and prevents secondary injury. SETTING: Institute of Spinal Cord Injury, Sun Yat-sen University, China. METHODS: After laminectomy was performed and contusive spinal cord injuries were induced in adult female Macaca rhesus, three received intrathecal papaverine, and three received saline 0.9% for control. SCBF was registered by laser-Doppler recording technique continuously for 180 min after injection. Histological analyses and microvessel density (MVD) were used for evaluation of spinal cord injury, and the percentage of spared spinal cord area was calculated. RESULTS: Mean arterial blood pressure showed no significant change in both groups. In the papaverine group, SCBF recovered to 81.35+/-7.8% of baseline at 15 min, 75.24+/-6.3% at 30 min, 73.38+/-2.3% at 90 min and 72.57+/-4.1% at 180 min after the completion of infusion. SCBF was significantly higher than the control groups (P<0.01). There was no occlusion of the arteries, but occluded veins were identified at the injured site. The MVD in the spinal cord of the control group was significantly lesser than the papaverine group (P<0.01). Luxol Fast Blue staining showed that intrathecal papaverine reduced myelin loss in the lesion 2 weeks after injury (P<0.05). CONCLUSION: Intrathecal administration of papaverine increased SCBF in non-human primates. It is likely that the effects of papaverine can reduce secondary injury in spinal cord injured Macaca rhesus.