Hadzic's Regional Anesthesia > Part IV. New and Emerging Concepts in Peripheral Nerve Blocks: Equipment and Practice > Chapter 45. Percutaneous Nerve Localization William F. Urmey, MD

Percutaneous Nerve Localization: Introduction

"Conventional methods for peripheral nerve or plexus blockade have involved the identification of surface anatomic landmarks. Such landmarks serve as an approximate starting point for a search for the targeted nerve or nerves by needle exploration. The objective of needle exploration is to reach a finite endpoint that indicates the tip of the needle is sufficiently close to the targeted nerve or nerve plexuses. Two distinct types of endpoint exist.1. An anatomic endpoint based on encountering anatomic relations to the targeted nerve or nerves. Examples of blocks that make use of anatomic endpoints include field block, transarterial techniques, or ultrasonographic guidance.

2. A functional endpoint based on a nerve response to mechanical or electrical stimulation. The main types of functional endpoints used clinically are either sensory response to mechanical stimulation of the nerve (mechanical paresthesia) or a motor response to electrical stimulation.

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