Brachial Artery Vasospasm Caused by Cervical Dorsal Root Ganglion Degeneration after Subarachnoid Hemorrhage: an Experimental Study

PURPOSE: Subarachnoid hemorrhage (SAH) may lead to vasospasm in various vessels. The cervical nerves have a vasodilatory effect on the upper extremity arteries. The aim of this study was to investigate if there is a relationship between C6 dorsal root ganglion (DRG) degeneration and brachial artery (BA) vasospasm after spinal SAH. METHODS: This experimental study was conducted on 23 rabbits. The animals were divided into 3 groups: control (n = 5), SHAM (n = 5), and study group (n = 13). One cubic centimeter (cc) of serum saline was injected into the cisterna magna of animals of the SHAM group; the same procedure was performed by 1 cc of homologous blood in the study group. Degenerated neuron densities (DNDs) of DRGs (n/mm(3)) at C6 levels and BA vasospasm indexes (VSI; wall surface/lumen surface) of all animals were determined and results were analyzed statistically. RESULTS: Mean VSI values of BAs and DNDs of C(6)DRGs of the control, SHAM, and study groups were estimated as 10 +/- 3/1.12 +/- 0.11 n/mm(3), 34 +/- 9/1.27 +/- 0.24 n/mm(3), and 1031 +/- 145/2.93 +/- 0.78 n/mm(3), respectively. Mean DNDs and VSI values were statistically significantly different between the control and study groups (P < 0.0001). CONCLUSIONS: C(6)DRG degeneration may be considered as an important factor in the etiopathogenesis of severe BA vasospasm after SAH.