Gelatin-agar lumbosacral spine phantom: a simple model for learning the basic skills required to perform real-time sonographically guided central neuraxial blocks.

This report describes the preparation of a gelatin-agar spine phantom that was used for spinal sonography and to practice the hand-eye coordination skills required to perform sonographically guided central neuraxial blocks. The phantom was prepared by embedding a lumbosacral spine model into a mixture of gelatin and agar in a plastic box. Cellulose powder and chlorhexidine were also added to the mixture, after which it was allowed to solidify. Sonography of the osseous elements of the lumbosacral spine in the phantom was then performed, and their sonographic appearances were compared to those in volunteers. Simulated real-time sonographically guided paramedian spinal needle insertions were also performed in the phantom. The texture and echogenicity of the phantom were subjectively comparable to those of tissue in vivo. The osseous elements of the spine in the phantom were clearly delineated, and their sonographic appearances were comparable to those seen in vivo in the volunteers. During the simulated sonographically guided spinal injections, the needle could be clearly visualized, but the phantom provided little tactile feedback. In conclusion, the gelatin-agar spine phantom is a simple and inexpensive sonographic spine model that has a tissuelike texture and echogenicity. It can be used to study the osseous anatomy of the lumbar spine and practice the skills required to perform sonographically guided central neuraxial blocks.