Single Needle Approach for Multiple Medial Branch Blocks: A New Technique

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Abstract
Medial branch blocks are an important tool for the diagnosis of facet joint arthropathy. The most commonly used technique involves multiple needle placements, one for each nerve blocked. This multiple needle technique may require a large amount of local anesthetic for anesthetizing the skin, thereby increasing the rate of false-positive blocks. Diagnostic lumbar medial branch blocks are usually performed using multiple needles, one for each branch. The authors describe a different technique using a single needle for all levels. Initially, the needle is directed toward the medial branch located at the level of the affected facet joint in the antero–posterior view. After anesthetizing this nerve with local anesthetic, the same needle is withdrawn to the skin with the tip still in the subcutaneous tissue and repositioned to block the medial branch above, and thereafter below, while continuing to use only the antero–posterior view, thereby using only one entry site. When performed correctly, the single needle technique provides accuracy similar to the more conventional multiple needle approach during the performance of diagnostic facet joint nerve blocks. Because only one skin entry point is needed, however, this technique may afford several advantages over the multiple needle approach. These may include less patient discomfort, less time required and less radiation exposure since only one C-arm position is used, a smaller volume of local anesthetic, and possibly a lower incidence of false-positive blocks.