Transforaminal or translaminar approach for dorsal root ganglion and dorsal nerve root. Anatomical reason for technique decision

Abstract

Radiculopathy is probably one of the most frequent types of pain seen in Pain Clinics. Invasive techniques such as transforaminal or translaminar injections are used when other conservative methods have failed. In these procedures, medication such as corticosteroids and local anaesthetics are injected next to the dorsal root ganglion and dorsal nerve root. The decision to use one or another approach depends on factors such as the region to treat (cervical, dorsal or lumbar), the characteristics and the cause of the pain. In this study we review the anatomical and histological aspects that can influence the decision to use each of these techniques for the treatment of radicular pain. We describe the morphology of the intervertebral foramen, its dimensions and the vascular supply of spinal cord and intervertebral foramen. We also analyze ultrastructural details that may help understand the role of spinal nerve root cuffs and other structures such as capillaries and fat that plays an important role on the spread of substances injected in the epidural space and in transforaminal blockade. This review includes a microscopic analysis of the corticosteroids used and in some cases related to the complications published.

Case series of fluoroscopic findings and 3D reconstruction of human spinal MRIs of the space of Okada

“…Fluoroscopy allows clinicians to confirm the correct spread of injected solutions, typically corticosteroids, and local anesthetic agents. The transforaminal approach allows the solution to reach the external surface of the dural cuff within the neural‐foraminal canal (NFC) (Reina et al, 2010; Reina, De Andrés, Machés, & Prats, 2014). With this approach, the solution spreads among the adipocytes that surround the nerve root to the dorsal root ganglia (DRG) (Hernández, Reina, & Prats‐Galino, 2011; Reina et al, 2008; Reina et al, 2011).…”

Successive changes in extraneural structures from the subarachnoid nerve roots to the peripheral nerve, influencing anesthetic block, and treatment of acute postoperative pain

“…The location of the DRG is different depending on the spinal level. In the cervical region it is located within the foraminal channel (Reina et al, 2002b, 2010b; De Andrés et al, 2009; Gilchrist et al, 2001); in the thoracic region it is closer to the medial aspect of the foramen and at lumbar and sacral regions it is within epidural space.…”