The efficacy of cervical spine phantoms for improving resident proficiency in performing ultrasound-guided cervical medial branch block

Background: Few studies have been conducted on the utility of cervical spine phantoms for practicing cervical procedures. Here, we describe a simple method for creating a cervical spine phantom and investigate whether the use of a gelatin-based phantom is associated with improved proficiency in performing ultrasound-guided cervical medial branch block. Methods: A cervical spine phantom was prepared using a cervical spine model immersed in a mixture of gelatin and psyllium husk. In total, 27 participants, inexperienced in spinal ultrasonography, were enrolled and allocated to 1 of 2 groups (training group, n = 18; control group, n = 9). All participants were tested (test-1) following an introductory course of basic ultrasonography. Participants in the control group were tested again after 1 week (test-2). Those in the training group received a further individual 3-hour training session, and were tested again after 1 week (test-2). Results: The mean performance score in test-1 was 62.5 ± 10.1 points in the training group and 62.3 ± 4.1 points in the control group [95% confidence interval (95% CI) −5.5 to 5.8; P  = .954]. In test-2, the mean score was 86.8 ± 6.5 points and 59.9 ± 4.4 points in the training and control groups, respectively (95% CI 21.9–31.8; P  < .001). The mean time required to complete test-1 was 84.6 ± 26.6 seconds in training group and 90.7 ± 43.9 seconds in the control group (95% CI −34.0 to 21.7; P  = .653); in test-2, the time required was 56.6 ± 27.9 and 91.2 ± 43.8 seconds (95% CI −63.0 to −6.2; P  = .019), respectively. Interobserver reliability showed excellent agreement based on the intraclass correlation coefficient, and moderate to almost perfect agreement by kappa statistics. Conclusion: Training using a gelatin-based cervical spine phantom helps novices acquire the skills necessary to perform ultrasound-guided cervical medial branch blocks.