Assessment of sympathetic nerve activity after C 6 stellate ganglion block in the orofacial region - The influence with needle tip position and local anesthetic volume

Stellate ganglion block (SGB) is the most popular treatment in orofacial pain clinics. This work investigates the effects of C 6 SGB, with special reference to the sympathetic blockade in the orofacial region and discomfort of dysphagia. The effect of sympathetic blockade was evaluated by changes in pupil diameter and skin temperature in the facial region and the hand. Ten patients with trigeminal neuropathy who came to our clinic were studied (8 female, 2 male, age 22.8±7.7 years). We performed the SGB four times using different volumes of 1% mepivacaine at different needle positions in all patients on different days. Patients were divided in four groups : B 3 : SGB at base of 6 th transverse process using 3 ml of 1% mepivacaine. B 5 : Same as B 3, but using 5 ml of the same anesthetic. A 3 : SGB at anterior tubercle of 6 th transverse process using 3 ml of the same anesthetic. A 5 : Same as A 3, but using 5 ml of the same anesthetic (Fig. 1). The measurements of skin temperature and pupil diameter were performed at pre-SGB, 15, 30, 60, and 90 minutes after SGB. The difference in pupil diameter between SGB and contralateral side in groups A 3 and A 5 were significantly smaller than that of groups B 3 and B 5 (p < 0.05) (Fig. 2). The difference in hand and finger skin temperature between groups B 3 and B 5 was significantly larger than the difference between groups A 3 and A 5 (p < 0.05). There were no significant differences between the A groups and the control group (Fig. 3). The facial skin temperature differences between groups A 3 and A 5 were significantly larger than the difference between groups B 3 and B 5 (p<0.05) (Fig. 4). Another group of patients (62 female, 18 male, age 32.8 ±9.2 years) were subjects of another investigation about dysphagia. The complaint of dysphagia appeared significantly more frequently in A 5 than in A 3, B 3 and B 5 (p<0.05) (Table 1). In conclusion, C 6 SGB at anterior tubercle of 6 th transverse process using 1% mepivacaine of 3 ml was considered to be superior to the C 6 SGB at base of transverse process using 3 or 5 ml of the same anesthetics in sympathetic blockade in the orofacial region, with less incidence of dysphagia.