Effects of Nimodipine on Posttraumatic Spinal Cord Ischemia in Baboons

Abstract

Posttraumatic ischemia appears to be largely responsible for the extension of lesions in acute injury of the spinal cord. In the present study, we have evaluated the putative improvement of axonal function by the calcium channel blocker nimodipine after acute trauma of the spinal cord. Three techniques were used: (1) spinal cord blood flow (SCBF) using a scanographic technique with stable xenon, (2) somatosensory evoked potentials (SEPs), and (3) magnetic resonance imaging (MRI). Thirteen baboons were used in this study. Acute trauma was achieved by compression of the spinal cord at level L1 by applying pressure for 5 sec with an inflated balloon catheter injected with Ringer's solution. Following the injury, one group (n = 5) received a saline infusion (placebo) for seven days, and a second group (n = 8) received a nimodipine infusion (0.04 mg/kg/h) during the same period of time. SCBF and SEP were first recorded prior to trauma. SCBF, SEPs, and MRI were then recorded on the day of the injury and eight days prior to histologic examination of the spinal cord. In these studies nimodipine significantly improved SCBF. The decrease in SCBF observed at day one and day eight following trauma was significantly reduced in the treated group. Two baboons in the treated group also showed improvement of axonal function as assessed by SEP. No significant difference was observed with MRI, however, histologic study revealed that the lesions were significantly smaller in the treated group. Based on these observations we conclude that a week of nimodipine treatment following spinal cord injury enhances SCBF, limits the size of the spinal cord lesion, and perhaps improves functional recovery.

Correlation between spinal cord blood flow and arterial diameter following acute spinal cord injury in rats

“…Several reports have suggested the efficacy of nimodipine in increasing SCBF following spinal cord injury [9,22], although some reports have failed to demonstrate any efficacy [8,12]. Nimodipine induces relaxation of cerebral vessels in in vivo and in vitro preparations [1,28].…”

“…Many studies on spinal cord blood flow (SCBF) have already been performed. Based on these studies, calcium channel antagonists such as nimodipine have attracted attention as possible agents for improving SCBF [9,22], although some authors have reported no beneficial effect of nimodipine on axonal function [12]. More work is needed to determine how the vessels of the spinal cord react following injury.…”

The effect of nimodipine and prednisolone on traumatic facial nerve injury treatment

“…In various studies, nimodipine used in the treatment of laryngeal nerve injury is shown to accelerate recovery period, and this is supported by objective measurements (EMG). [28][29][30] Pointillart et al [31] defined the therapeutic effect of 1week nimodipine administration on spinal cord injury by increasing blood flow. He stated significant improvement in neurologic signs after administering methylprednisolone and nimodipine to 100 patients with spinal cord injury in…”

Current Concepts in the Management of Acute Spinal Cord Injury

“…28 Nimodipine also supported spinal cord blood flow when used in baboons with compressive spinal cord lesions at a dosage of 0.02 mg/kg/hour for 2 hours and then 0.04 mg/kg/hour for 1 week. 46 Neither of these studies evaluated functional recovery. Other groups, using similar injury models and comparable drug regimes, have been unable to demonstrate a beneficial effect of nimodipine in spinal cord injury, bringing the efficacy of nimodipine into question.…”