Changes in blood flow at the mandibular angle and Horner syndrome in a rat model of superior cervical ganglion block

Background: A stellate ganglion block (SGB) causes increased blood flow in the maxillofacial region, exhibiting the potential for regenerative effects in damaged tissue. The focus of this study was to understand the efficacy of SGB for regenerative effects against nerve damage. A rat model of the superior cervical ganglion block (SCGB) was created instead of SGB, and facial blood flow, as well as sympathetic nervous system function, were measured. Methods: A vertical incision was made on the left side of the neck of a Wistar rat, and a 5-mm resection of the superior cervical ganglion was performed at the back of the bifurcation of the internal and external branches of the left common carotid artery. Blood flow in the skin at the mandibular angle and mean facial temperature were measured using a laser-Doppler blood flow meter and a thermographic camera, respectively, over a 5-week period after the block. In addition, the degree of ptosis and miosis were assessed over a period of 6 months. Results: The SCGB rat showed significantly higher blood flow at the mandibular angle on the block side (P < 0.05) for 3 weeks, and significantly higher skin temperature (P < 0.05) for 1 week after the block. In the SCGB rat, ptosis and miosis occurred immediately after the block, and persisted even 6 months later. Conclusions: SCGB in rats can cause an increase in the blood flow that persists over 3 weeks.