It should preferentially stimulate the dendrites and not produce paresthesia. In addition, it must penetrate beyond Lamina I to active Lamina II-IV. We need the field to swing over to the lateral aspect of the dorsal horn. Stimulating the dendrite poses several challenges. 6 This has led to the hypothesis that stimulation of the dendrite might affect pain pathways in humans. 5 Dorsal horn dendrites are also attractive targets because they are involved in long-term potentiation of synaptic strength (LTP) in nociceptive pathways. 4 Animal studies have established that abnormalities of dendritic spine morphology are associated with abnormal nociceptive function, including neuropathic pain. 3 It is divided into six layers, known as laminae, and comprise a number of different cell types: islet cells, filamentous cells, curly cells and stellate cells. Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn of the human spinal cord is recognized as a key site for initial pain processing. However, in recent years, the attention of researchers has turned to non-axonal stimulation targets, such as dorsal columns, dorsal roots, and dorsal horns. Conventional techniques have focused on axons in the dorsal column. Technological advances in stimulator design and treatment protocols have not correlated with significant improvements in clinical outcomes, and we may be reaching the limits of what can be achieved using established techniques. 1 However, our incomplete understanding of the mechanisms underlying pain relief by SCS has led to a plateau in efficacy. Spinal cord stimulation (SCS) is an established technique for the treatment of chronic pain associated with many different disease entities, including neuropathic pain, intractable pain, headache, and angina pain, and its clinical efficacy is well documented. J Comp Neurol.President, International Neuromodulation Societyĭirector of Hunter Pain Specialists, Hamilton Day Surgery Centre, Genesis Research Services, Broadmeadow, AustraliaĬo-Director, Innervate Pain Management Program, Newcastle, AustraliaĬhronic pain is a heterogenous, complex condition that is associated with significant burdens for both patients and the healthcare systems. Wang CC, Willis WD, Westlund KN (1999) Ascending Projections from the Area of the Spinal Cord around the Central Canal: A Phaseolus Vulgaris Leucoagglutinin Study in Rats. Rustioni A (1973) Non-Primary Afferents to the Nucleus Gracilis from the Lumbar Cord of the Cat. Malcolm A, Phillips SF, Kellow JE, Cousins MJ (2001) Direct Clinical Evidence for Spinal Hyperalgesia in a Patient with Irritable Bowel Syndrome. Kuo DC, De Groat WC (1985) Primary Afferent Projections of the Major Splanchnic Nerve to the Spinal Cord and the Nucleus Gracilis of the Cat. Hirshberg RM, Al-Chaer ED, Lawand NB, Westlund KN, Willis WD (1996) Is there a Pathway in the Dorsal Funiculus that Signals Visceral Pain? Pain 67:291–305 Giuffrida R, Rustioni A (1992) Dorsal Root Ganglion Neurons Projecting to the Dorsal Column Nuclei of Rats. Giesler GJ, Nahin RL, Madsen AM (1984) Postsynaptic Dorsal Column Pathway of the Rat. Distribution of Ascending Afferent Fibers. Brain Res 77:1–23Ĭliffer KD, Giesler GJ (1989) Postsynaptic Dorsal Column Pathway of the Rat. J Neurophysiol 82:1876–1882Ĭampbell SK, Parker TD, Welker W (1974) Somatotopic Organization of the External Cuneate Nucleus in Albino Rats. J Neurophysiol 79: 3143–3150Īl-Chaer ED, Feng Y, Willis WD (1999) A Comparative Study of Viscerosomatic Input onto Postsynaptic Dorsal Column and Spinothalamic Tract Neurons in the Primate. NeuroReport 8: 3267–3273Īl-Chaer ED, Feng Y, Willis WD (1998) A Role for the Dorsal Column in Nociceptive Visceral Input into the Thalamus of Primates. J Neurophysiol 78:521–527Īl-Chaer ED, Westlund KN, Willis WD (1997b) Effects of Colon Inflammation on the Responses of Postsynaptic Dorsal Column Cells to Visceral and Cutaneous Stimulation. J Neurophysiol 76:2675–2690Īl-Chaer ED, Westlund KN, Willis WD (1997a) The Nucleus Gracilis: An Integrator for Visceral and Somatic Information. J Neurophysiol 76:2661–2674Īl-Chaer ED, Lawand NB, Westlund KN, Willis WD (1996b) Pelvic Visceral Input into the Nucleus Gracilis is Largely Mediated by the Postsynaptic Dorsal Column Pathway.
Al-Chaer ED, Lawand NB, Westlund KN, Willis WD (1996a) Visceral Nociceptive Input into the Ventral Posterolateral Nucleus of the Thalamus: A New Function of the Dorsal Column.