Block On!

Terese T. Horlocker, MD, Rochester, MN

February, 2006

The clinical evidence in support of peripheral nerve blocks (PNBs) is mounting. PNBs provide superior pain control without inducing opioid-like side effects, and they greatly reduce the potential for neuraxial bleeding and infection associated with spinal and epidural anesthesia. The scarcity of case reports in the literature on PNB complications suggests that the risk of serious morbidity is minimal.

If PNBs are to become the standard of care for some types of cases, it's imperative that more practitioners commit to getting the post-graduate training needed to perform them. PNBs often require multiple injections, increased onset time and larger volumes of local anesthetic solutions than neuraxial blocks. To administer them, physicians need a deep understanding of the pharmacokinetics and pharmacodynamics of modern analgesic agents; the ability to visualize spacial relationships between nerves, vessels and skin; and manual dexterity.

Most residency programs do not adequately prepare physicians for these challenges. A recent survey of 60 anesthesiology residency program directors showed that just over half offered a PNB rotation. During the rotation, the number of blocks done by each resident varied from just two (supraclavicular) to 10 (axillary) each, and the programs used multimedia, mannequins and cadaver dissection infrequently. In contrast, research suggests that competence in neuraxial blocks, which are considerably less challenging, requires 45 to 60 attempts during training.

For now, thorough post-graduate training is the answer. All practitioners who are planning to begin a PNB practice should start by participating in intensive, hands-on workshops like those sponsored by the American Society of Regional Anesthesia and Pain Medicine and the American Society of Anesthesiologists. Workshops that involve cadaveric specimens and anatomic and live models are ideal. An excellent next step is to visit an established PNB center, not only for clinical learning but to better understand how to train the staff and prepare the surgical facility. All told, for established practitioners skilled at neuraxial anesthesia, 20 to 25 procedures may be needed to achieve proficiency in each type of block.

I personally became interested in PNB techniques after conducting research on patients who developed neuraxial hematomas after spinal and epidural blocks, because PNB techniques provide superior analgesia without the risk of spinal hematoma (and paralysis). I learned them largely through self-teaching, after an extensive review of the anatomy and technical aspects. During this time, I took a very deliberate approach. I selected patients with optimal anatomy, and I allowed extra time for both block performance and block onset. And, I adopted the philosophy that I would not hesitate to convert to a spinal or epidural approach if needed.

In my opinion, it's time for practitioners to invest in the thorough training we need to perform PNBs well. This will allow us to continue sending our patients home sooner after major surgeries, free of significant pain and better positioned for full recovery.

Dr. Horlocker is Associate Professor of Anesthesiology and Orthopedics at the Mayo Clinic College of Medicine and Past President of the American Society of Regional Anesthesia and Pain Medicine (ASRA).


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