Nerve block using a navigation system and ultrasound imaging for regional anesthesia

During the last few years, regional anesthesia using ultrasound imaging has increased dramatically in both clinical and research areas. This method provides a direct noninvasive imaging of the targeted nerve and the tissue around it in real time. Furthermore, it allows anesthetists to observe the injected anesthetics for optimal distribution. However, there are still some major limitations to this method such as poor visibility of the standard needle tip and shaft, tricky location estimation of needle tip, and difficult needle alignment before and during insertion. This article presents the concept of a new application field of medical navigation for regional anesthesia using ultrasound imaging, to avoid the above-mentioned drawbacks. In addition, a laboratory experiment on a phantom to verify the effectiveness, safety, precision and handling of the navigation method in comparison with standard ultrasound-guided regional anesthesia is described. During the experiment ten test persons who have no experience in this field should touch a target in a phantom, avoiding contact with the simulated blood vessels and nerve. Each test person was asked to repeat the test five times with and without navigation assistance, respectively. Thereafter, a two-sample one-tailed paired t-test with a significance level of 1% was applied to statistically analyze the difference. The results show that navigation assistance significantly improves effectiveness, safety, precision and handling of ultrasound-guided regional anesthesia.