Old anatomy and new anatomical concepts for single shot and continuous spinal anesthesia

Abstract

This educational article shows the anatomy studied in cadavers and the latest imaging technology for spinal anesthesia. Neuraxial anesthesia is one of the regional anesthetic options that can be done by blocking the spinal cord neural transmission through the administration of local anesthetics either via intrathecal, epidural, continuous spinal anesthesia, or combined epidural-spinal anesthesia. Several descriptions of the spinal canal anatomy have been reported since the 16th century by Leonardo da Vinci, and the use of modern radiological imaging technology has provided important insights into understanding anatomical and pathophysiological aspects implicated in spinal anesthesia. The vertebral level at which the spinal cord finishes varies widely from T12 to the L3-L4 intervertebral disc and the spinal cord extends to the L1-L2 and the L2-L3. In this educational study, cadaver anatomy and new approaches with ultrasound, magnetic resonance imaging, computed tomography, and fluoroscopy will be covered, to approach spinal and continuous spinal anesthesia. Between the medulla and any given level of the spinal cord, the fibers of the anterolateral system and posterior columns are dissociated. Despite all the new imaging studies to assist in performing subarachnoid punctures for single shot or continuous spinal anesthesia, anatomical landmarks remain the most used for both the lumbar and thoracic approaches.