Facilitating needle alignment in-plane to an ultrasound beam using a portable laser unit.

OBJECTIVE: Ultrasound guidance can increase success with peripheral nerve blocks. Accurate anesthetic injection is optimized with both clear visualization and fine adjustment of the needle tip at the target area. Good needle alignment with the ultrasound beam and using a freehand technique are both desirable for these conditions. The purpose of this report is to describe how a unique, in-plane laser guide may be used to improve the alignment of injection needles with ultrasound beams in order to promote best needle tip visualization. ILLUSTRATION IMAGES: By using a small, battery-operated laser unit mounted onto an ultrasound transducer, a method to align the ultrasound scanning plane and laser-line projection plane was developed. Such alignment was further demonstrated and illustrated in a water bath model. Ultrasound was then used to show how clearly the needle shaft and tip can be visualized after needle alignment to the ultrasound beam using the laser line shining on the shaft of the needle.
CONCLUSION: This in vitro demonstration describes the potential use of a readily available laser-line unit to assist with in-plane needle alignment with the ultrasound plane in order to ultimately improve needle visibility during ultrasound-guided peripheral nerve block. It requires minimum specialized training and may allow for maximum flexibility with freehand needle insertions in a sterile fashion.