Innovative Approaches to Neuraxial Blockade in Children: The Introduction of Epidural Nerve Root Stimulation and Ultrasound Guidance for Epidural Catheter Placement

Abstract

Continuous epidural blockade remains the cornerstone of pediatric regional anesthesia. However, the risk of catastrophic trauma to the spinal cord when inserting direct thoracic and high lumbar epidural needles in anesthetized or heavily sedated pediatric patients is a concern. To reduce this risk, research has focused on low lumbar or caudal blocks (ie, avoiding the spinal cord) and threading catheters from distal puncture sites in a cephalad direction. However, with conventional epidural techniques, including loss-of-resistance for localization of the needle, optimal catheter tip placement is difficult to assess because considerable distances are required during threading. Novel approaches include electrical epidural stimulation for physiological confirmation and segmental localization of epidural catheters, and ultrasound guidance for assessing related neuroanatomy and real-time observation of the needle puncture and, potentially, catheter advancement. The present article provides a brief and focused review of these two advances, and outlines recent clinical experiences relevant to pediatric epidural anesthesia.

Major complications related to epidural analgesia in children: a 15-year audit of 3,152 epidurals

“…In infants and neonates, ultrasound enables visualization of epidural catheters that are inserted via the easily accessible caudal space and threaded to the desired vertebral level in the thoracic or lumbar regions. [33][34][35] The availability of ultrasound to guide placement of caudal-thoracic epidurals has resulted in an increased use of epidural analgesia in infants during the last three years of this review.…”

Confirmation of Loss-of-Resistance for Epidural Analgesia

“…[64][65][66] Ultrasonography In the last decade, propelled by technological improvements, US has become an increasingly popular adjunct for neuraxial blocks. [67][68][69][70] Currently, there exist 2 methods to assist with epidural catheter insertion: preprocedural US scanning and real-time US guidance. 68 With preprocedural scanning, a US examination is carried out to identify the relevant anatomy (intervertebral level/spinous process/lamina), insonate the window between contiguous spinous processes/laminas, and determine the depth of the ligamentum flavum/dura complex.…”

“…However, dural displacement with LA injection could serve as a surrogate marker. 67 Thus, further trials are required to investigate US guidance's ability to differentiate true from false-positive LOR.…”

Evaluation of electric neurostimulation to confirm correct placement of lumbosacral epidural injections in dogs

“…2,4,6 In human medicine, electric nerve stimulation has been reported as a means to confirm proper placement of a needle in the epidural space. [7][8][9][10][11][12] For example, when the needle is in the epidural space, a small electric stimulus will elicit contraction of the muscles innervated by the stimulated nerves of the spinal cord. If the needle is outside of the epidural space, a much greater stimulus is required to induce the same muscle contraction.…”