Hadzic's Regional Anesthesia > Part IV. New and Emerging Concepts in Peripheral Nerve Blocks: Equipment and Practice > Chapter 47. Injection & Current Delivery Monitoring Christopher Robards, MD, Admir Hadzic, MD

General Considerations

"Only in the past decade or so has research on functional regional anesthesia anatomy, outcome, and equipment slowly begun to transform regional anesthesia into a modern discipline. However, in many ways the equipment used for peripheral nerve block remains in its infancy. The sophistication and functionality of the equipment used for peripheral nerve blocks (PNBs) are, at best, rudimentary and lag far behind those of general anesthesia, as depicted in the following examples.Spinal cord injury after interscalene block is perhaps the most serious complication of a PNB. This devastating complication, however, can occur only with an excessively deep needle insertion (ie, >2.5 cm).¹ Monitoring the depth of the needle insertion is substantially important to avoid a too-deep insertion (eg, spinal cord or chest cavity with interscalene block). In fact, the recently suggested standardized block documentation procedure requires clinicians to document the depth at which the needle is inserted. Nevertheless, most commercially available needles still do not have depth markings for such objective documentation.² Despite that fact, there is much work underway to remedy this deficiency, and it is inevitable that all needles used in regional anesthesia will eventually incorporate depth markings on their shafts...."