Effect of Cervical Sympathectomy on Ischemic Brain Damage Induced by Focal Cerebral Infarction in Rats / 대한마취과학회지

BACKGROUND: Recently Umeyama et al. reported that cerebral blood flow is definitely increased on the ipsilateral side after the blockade of stellate ganglion. Considering that the most obvious solution to the problem of poor cerebral blood flow is to augment the flow, cervical sympathectomy may reduce the volume and extent of the brain damage by increasing the cerebral blood flow. We studied the effects of cervical sympathectomy on ischemic brain damage in a middle cerebral artery occlusion model in rats. METHOD: The experimental animals were divided into three groups. In the sham-operated control group (n=7), middle cerebral artery was occluded without cervical sympathectomy. In the experimental group I (n=7), cervical sympathectomy was performed 5 minutes before middle cerebral artery occlusion. In the experimental group II (n=7), cervical sympathectomy was performed 5 minutes after middle cerebral artery occlusion. The neurological grade of each experimental animal was evaluated at 24 hours post occlusion and then the animals were sacrificed. The brain was cut into coronal sections. The volume of infarct was computed and the edema volume was calculated. RESULTS: 1. There were no differences in the physiological variables in all groups. 2. Cervical sympathectomy, compared with the controls, significantly reduced the volume of infarct (P<0.05). 3. There was no significant difference in ischemic brain edema between each group. 4. The neurologic deficit was less severe in sympathectomized groups compared with the control group (P<0.05). And neurological grades were significantly correlated with the volume of infarction (P<0.05). CONCLUSION: These results suggest that cervical sympathectomy may improve the neurologocal deficit and reduce the infarct volume measured 24 hours following induction of focal cerebral infarction.

Effect of Bilateral Superior Cervical Sympathectomy on Focal Cerebral Infarction Induced by Autologous Blood Clot in Rabbits / 대한마취과학회지

BACKGROUND: Many reports suggest that cervical sympathectomy improves cerebral blood flow. But the basal & medial areas of brain are innervated bilaterally, so unilateral sympathectomy may not improve the outcome of infarction of those areas effectively. Actually it was reported that only bilateral, not unilateral cervical sympathectomy increased the blood flow of thalamus which known to be innervated bilaterally, and also reported that unilateral sympathectomy did not reduce the infarct size of caudate nucleus. So we studied the effect of bilateral superior cervical sympathectomy on focal cerebral infarction. METHODS: Twenty rabbits were divided into two groups. In the sham-operated control group (n=10), focal infarction was achieved by administering an autologous blood clot into the internal carotid artery after exposure of bilateral superior cervical sympathetic ganglia. In the sympathectomy group (n=10), bilateral superior cervical sympathetic ganglia were excised following embolization. Seven hours after embolization, brains were sliced into 2 mm coronal sections, stained with 2,3,5-triphenyltetrazolium chloride, and infarct sizes were determined via image analysis. RESULTS: There were no differences in the physiologic variables between two groups. The percentage of infarct size was significantly greater in the control group as compared to the sympathectomy group in both cortex (23+/-8% vs 12+/-5%, respectively; P<0.05) and subcortical area (35+/-8% vs 17+/-8%, respectively; P<0.05). CONCLUSIONS: These results suggest that bilateral superior cervical sympathectomy may reduce the infarct size of subcortical area as well as of cerebral cortex measured at 7 hours following induction of focal cerebral infarction.

Effects of Cervical Sympathectomy on Mechanical Allodynia and Cold Allodynia in a Rat Model of Neuropathic Pain / 대한마취과학회지

BACKGROUND: The pathophysiologic mechanism of the neuropathic pain is still unclear. We designed this study to evaluate the effect of bilateral cervical sympathectomy on allodynia and the relationship of neuropathic pain with sympathetic nerve system of supraspinal level in rats experiencing neuropathic pain. METHODS: Neuropathic pain was produced by tight ligating the left 5th and 6th lumbar spinal nerves of male Sprague-Dawley rats. Mechanical allodynia was quantified by measuring the foot withdrawal frequency to stimuli with two von Frey filaments of 14.5 mN and 53.9 mN applied to the affected left hind paw, and cold allodynia was quantified with the same manner using 100% acetone. We divided the neuropathic pain models into experimental group (bilateral cervical sympathectomy) and control group (sham operation), and then measured the foot withdrawal frequency 1, 3, 5, 7, 14, 21 and 28 days postoperatively. RESULTS: In experimental group, the foot withdrawal frequency to mechanical stimuli with 14.5 and 53.9 mN of von Frey filament and cold stimuli with 100% acetone was significantly lower than that of control group for all postoperative observation points. Also, the experimental group showed decrease in foot withdrawal frequency compared with preoprative value over the course of the study. CONCLUSIONS: Bilateral cervical sympathectomy reduced mechanical allodynia and cold allodynia in the rat model of neuropathic pain suggesting that neuropathic pain, although the lesions are localized in low extremities, may be correlated with functional disturbance of sympathetic nerve fibers of supraspinal or brain level and help explain the mechanism of neuropathic pain.