Abstract
Cervical medial branch block (CMBB) has been recognized as an effective treatment for cervicogenic pain. Previous studies mostly used ultrasound-guided out-of-plane puncture for CMBB, while this prospective study was designed to investigate the efficacy of ultrasound-guided in-plane puncture, specifically focusing on the new target of CMBB for cervical pain. This study includes two parts: the accuracy study (N = 15, CMBB was completed by ultrasound and confirmed by computed tomography [CT], in which a good distribution percentage of the analgesic solution was observed) and the efficacy study (N = 40, CMBB was completed by ultrasound or CT, while the proportion of pain relief (numerical rating scale) decrease by more than 50% postoperatively was analyzed). The results showed that the good distribution percentage of the analgesic solution was 97.8%. Furthermore, in the early period (30 min and 2 h postoperatively), the proportion of patients with pain relief was lower in the ultrasound group than that in the CT group, especially at 2 h postoperatively (52% vs. 94%). However, at 24 h postoperatively and later, the proportion of patients with pain relief gradually stabilized to about 60%-70%, and lasted for about 2 weeks to 1 month. Therefore, the new target for CMBB, guided by ultrasound in-plane, offers high visibility and accuracy. A single CMBB performed under ultrasound guidance resulted in pain relief comparable to that of a CT-guided procedure (1 day to 1 month postoperatively). This study indicated that CMBB guided by ultrasound in-plane could be regarded as a promising approach for treatment of cervicogenic pain.