Hadzic's Peripheral Nerve Blocks and Anatomy for Ultrasound-Guided Regional Anesthesia, 2e > Section 6. Ultrasound-Guided Neuraxial and Perineuraxial Blocks > Chapter 43. Introduction Manoj Karmakar, Catherine Vandepitte

Introduction

"Central neuraxial blocks (CNBs), which include spinal, epidural, combined spinal epidural (CSE), and caudal epidural injections, are commonly practiced regional anesthesia techniques in the perioperative period, for obstetric anesthesia and analgesia, as well as for managing chronic pain.¹ Traditionally, CNBs are performed using surface anatomic landmarks, operator tactile sensation (loss of resistance) during needle advancement, and/or visualizing the free flow of cerebrospinal fluid. Although anatomic landmarks are fortuitous because spinous processes provide a relatively reliable surface landmark in many patients, they are not always easily recognized or reliable signs in patients with obesity,² edema, underlying spinal deformity, or after back surgery. Even in the absence of spine abnormalities, data suggest that a clinical estimate of a specific intervertebral space based on the surface anatomy may not be accurate in many patients.^3,4 In other words, a clinical estimate of an intervertebral space often results in needle placement one or two spinal levels higher than intended.^3,5,6 This estimation error has been attributed as a cause of injury of the conus medullaris or spinal cord after spinal anesthesia.^5,7 The difficulty of identifying the correct level is particularly present in patients with obesity and when accessing intervertebral space in the upper spinal levels.^3,5,7 Therefore, the Tuffier's line, a surface anatomic landmark that is used ubiquitously during CNB, is not a consistent..."