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Background: With ultrasound (US) guidance, the in-plane (IP) technique allows operators to track the needle in real time during its advancement towards the target nerve. While mastery of the IP technique is instrumental to the success (and safety) of peripheral nerve blocks, the optimal learning strategy for beginners has not been elucidated. In this randomized trial, using phantom gel models, we compared control-, self- and directed-learning for the acquisition of IP needle skills. We hypothesized that, compared to the 2 other groups, directed-learning would require a shorter performance time and fewer needle passes to complete the post-test.
Methods: Thirty novice operators (experience level<30 US-guided procedures in the 6 months prior to the study) were randomized to 1of 3 groups. In the control group, subjects underwent pre- and post-testing with no training in between. In the self-learning group, subjects underwent 1 hour of independent learning (needling of a practice phantom model) between the pre- and post-tests. In the directed-learning group, 1 hour of learning through coaching and feedback was provided between the pre- and post-tests. Pre-tests and post-tests, which were identical, consisted of needling sonographic targets of varying sizes and depths, which were embedded in a test phantom model. The primary outcomes encompassed performance time and number of needle passes; secondary outcomes included the presence or frequency of 8 quality-compromising behaviors. All study variables were assessed by a blinded observer.
Results: Compared to the pre-tests, post-test performance times improved similarly in all 3 groups. However only subjects randomized to directed-learning showed a reduction in the number of needle passes as well as improvement in several quality-compromising behaviors.
Conclusion: A directed-learning session, integrating coaching and feedback, is pedagogically more productive than self-learning for beginners aiming to acquire US IP technique. Further trials are required to determine the IP technique learning curve for novice operators.