[Thermographic assessments of the sympathetic blockade by stellate ganglion block (1) Comparison between C7-SGB and C6-SGB in 40 patients].

We compared the degree in sympathetic blockade after C7-SGB (stellate ganglion block at the level of 7th vertebral transverse process) and the one after C6-SGB (SGB at the level of 6th cervical transverse process) using infrared thermography. Forty patients entered this study. C7-SGB was performed in 20 patients using 5 ml of 1% plain mepivacaine at the anterior aspect of 7th cervical transverse process, and C6-SGB in the remainder at the top of the anterior tubercle of 6th cervical transverse process. Thermography was performed before and 30 minutes after SGB. Temperature differences between right and left side after SGB were significantly larger than those before SGB on all measured sites in two groups (P less than 0.001-0.05). On the thenar, the hypothenar, the first, the second, the fourth, and the fifth finger tips, changes of skin temperature in the C7-SGB group were significantly larger than in the C6-SGB group (P less than 0.05). There were no significant differences on the forehead or the cheek in two groups. All patients showed Horner's sign. No severe side-effect occurred in either group. In conclusion, while effect of upper cervical sympathetic blockade after C7-SGB was similar to the one after C6-SGB, effect of lower cervical and upper thoracic sympathetic blockade after C7-SGB was more effective than that after C6-SGB.