Electrophysiological evaluation of chronic neuropathic pain of spinal cord injury origin

Abstract

The chronic neuropathic pain of spinal cord injury origin has been shown to be related to permanent neurochemical changes in the dorsal horn neurons thus producing spontaneous discharges of central nociceptive neurons resulting in chronic pain. There is a doubt, however, regarding the possible supraspinal neurogenic mechanism contributing to the generation of this chronic neuropathic pain phenomenon.

To address this issue we determinated the functional condition of the thalamocortical transsmission by obtaining somatosensory evoked potentials from the stimulation of median nerves in the group of 23 paraplegics suffering from chronic posttraumatic neuropathic pain. We prospectively collected and analysed data from 23 patients, 21 males and 2 females, aged from 22 to 59 years (mean age, 35.8 y) suffered from chronic neuropathic pain of the spinal cord and cauda equina injury origin who underwent neurophysiological investigation by obtaining somatosensory evoked potentials from the stimulation of median nerves. Somatosensory evoked potentials were defined according to three-grade scale: normal findings (C), slightly abnormal (B), abnormal findings (A). Our findings revealed pathological somatosensory evoked potentials in 17 patients (73.9%). Only 3 (13%) patients had normal findings, and 3 (13%) slightly abnormal according to our criteria. Pathological findings in a majority of our patients, with changes in the primary cortical complex N20-P25, could be indicative for the dysfunction of thalamocortical afferences in patients with paraplegic pain.

Keywords

neuropathic pain - spinal cord injury - somatosensory potentials

• References

• 1 Bonica J.J.. History of Pain Concepts and Therapies. In: Bonica JJ. (Editor) The Management of Pain. Philadelphia; Lea & Febiger: 1990: 2-18
• 2 Botterell EH, Callaghan JC, Jousse AT. Pain in paraplegia. Clinical management and surgical treatment. Proc R Soc Med 1954; 47: 281-288
• 3 Nashold BS. Paraplegia and pain. In: Nashold BS, Ovelmen- Levitt J. (Eds) Deafferentation pain syndromes: patophysiology and treatment. Advances in pain research and therapy. New York; Raven Press Ltd: 1991. 19 301-330
• 4 Tasker RR, de Carvalho GTC, Dolan EJ. Intractable pain of spinal cord origin: clinical features and implications for surgery. J Neurosurg 1992; 77: 373-378
• 5 Ovelmen-Levitt J. The neurobiology of spinal cord dorsal horn and pathophysiology of neuropathic pain. In: Nashold BS, Pearlstein RD, Friedman AH, Ovelmen-Levitt J. (eds) The DREZ Operation. Park Ridge, Illinois; The American Association of Neurological Surgeons: 1996: 13-26
• 6 Ditunno JF, Young W, Donovan WH, Greasey G. The international standards booklet for neurological and functional classification of spinal cord injury. Paraplegia 1994; 32: 70-80
• 7 Spaic M, Markovic N, Tadic R. Microsurgical DREZotomy for Pain of Spinal Cord and Cauda Equina Injury Origin: Clinical Characteristics of Pain and Implications for Surgery in a Series of 26 Patients. Acta Neurochir (Wien) 2002; 144: 453-462
• 8 Jasper HH. The ten-twenty electrode system of the International Federation. Electroencephalogr Clin Neurophysiol 1958; 10: 89-92
• 9 Chiappa KH. Principles of Evoked Potentials. In: Chiappa KH. (Editor) Evoked Potentials in Clinical Medicine. Philadelphia; Lippnicott-Raven Publishers: 1997: 1-31
• 10 Dinner DS, Luders H, Lesser RP, Morris HN. Cortical generators of somatosensory evoked potentials to median nerve stimulation. Neurology 1987; 137: 1141-1145
• 11 Emerson RG, Pedley TA. Generators sources of median somatosensory evoked potentials. J Clin Neurophysiol 1986; 01: 159-202
• 12 Chiappa KH, Hill RA. Short-Latency Somatosensory Evoked Potentials: Interpretation. In: Chiappa KH. (editor) Evoked Potentials in Clinical Medicine. Philadelphia; Lippnicott- Raven Publishers: 1997: 341-401
• 13 Jeanmonod D, Sindou M, Magnin M, Boudet M. Intraopetrative unit recordings in the human dorsal horn with a simplified floating microelectrode. Electroencephalogr Clin Neurophysiol 1989; 72: 450-454
• 14 Nashold JRB. The Surgical Technique of the DREZ Operation. In: Nashold BS, Pearlstein RD, Friedman AH, Ovelmen-Levitt J. editor The DREZ Operation. Park Ridge, Illinois; The American Association of Neurological Surgeons: 1996: 73-93
• 15 Friedman AH, Nashold BS. Pain of spinal origin. In: Youmans JR. (Editor) Neurological Surgery. Philadelphia; WB Saunders: 1990. Vol 6 3950-3959
• 16 Friedman AH, Nashold BS. DREZ lesions for relief of pain related to spinal cord injury. J Neurosurg 1996; 65: 465-469
• 17 Bullitt E, Friedman AH. DREZ lesions in the treatment of pain following spinal cord injury. In: Nashold BS, Pearlstein RD, Friedman AH, Ovelmen-Levitt J. (Eds) The DREZ Operation. Park Ridge, Illinois; The American Association of Neurological Surgeons: 1996: 125-137
• 18 Rath SA, Braun V, Soliman N, Antoniadis G, Richter HP. Results of DREZ coagulations for pain related to plexus lesions, spinal cord injuries and postherpetic neuralgia. Acta Neurochir (Wien) 1996; 138: 364-369
• 19 Sindou M, Mertens P, Wael M. Microsurgical. DREZotomy for pain due to spinal cord and/or cauda equina injuries: longterm results in a series of 44 patients. Pain 2001; 92: 159-171
• 20 Kaplitt MG, Rezai AP, Lozano AM, Tasker R. Deep Brain Stimulation for Chronic Pain. In: Winn RN. (Editor) Youmans Neurological Surgery. Philadelphia; Saunders: 2004: 3119-3131
• 21 Pons TP, Garraghty PE, Ommaya AK. Massive cortical reorganization after sensory deafferentation in adult macaques. Science 1991; 252: 1857-1860
• 22 Kaas JH. Plasticity of sensory and motor maps in adult mammals. Ann Rev Neurosci 1991; 14: 137-167
• 23 Tunks ET. Pain in spinal cord injured patients. In: Bloch RF, Basbaum M. (Eds) Management of spinal cord injuries. Baltimore; Williams and Wilkins: 1986: 180-211
• 24 Tasker RR, De Carvalho GTC. Central pain of spinal cord origin. In: North RB, Levy MR. (Eds) Neurosurgical management of pain. Berlin; Springer: 1997: 110-117
• 25 Lenz FA, Gracely RH, Baker FH, Richardson RT. Reorganization of sensory modalities evoked by microstimulation in region of the thalamic principal sensory nucleus in patients with pain due to nervous system injury. J Comp Neurol 1998; 399: 125-138
• 26 Borsook D, Bacerra L, Comite A, Gonzales G, Breiter H. Neuroimaging of Pain: Possibilities of Objective Measurments of Analgesic Actions in Human Subjects. In: Bountra C, Monglani R, Schmidt WK. (Eds) Pain, Current Understanding, Emerging Therapies and Novel Approaches to Drug Discovery. New York; Marcel Dekker, Inc.: 2003: 149-159
• 27 Gonzales GR, Casey KL. Central Pain Syndromes. In: Jensen TS, Wilson PR, Rice HSC. (Eds) Clinical Pain Management: Chronic Pain. Oxford; University Press Inc: 2003: 403-417
• 28 Kiss ZH, Dostrovsky JO, Tasker RR. Plasticity in human somatosensory thalamus as a result of deafferentation. Stereotact Funct Neurosurg 1994; 62: 153-163
• 29 Dostrovsky JO. Immediate and long-term plasticity in human somatosensory thalamus and its involvement in phantom limbs. Pain 1999; 06: 37-43
• 30 Pattany PM, Yezierski RP, Widerstrom-Noga EG. et al Proton magnetic resonance spectroscopy of the thalamus in patients with chronic neuropathic pain after spinal cord injury. AJNR Am J Neuroradiol. 2002; 23: 901-905
• 31 Flor H, Elbert T, Knecht S. et al Phantom-limb pain as a perceptual correlate of cortical reorganization following arm amputation. Nature 1995; 375: 482-484
• 32 Ramachandran VS, Rogers-Ramachandran D, Stewart M. Perceptual correlates of massive cortical reorganization. Science 1992; 258: 1159-1160
• 33 Ramachandran VS, Rogers-Ramachandran D, Cobb S. Touching the phantom limb. Nature 1995; 377: 489-490
• 34 Iadarola MJ, Max MB, Berman KF. et al Unilateral decrease in thalamic activity observed with positron emission tomography in patients with chronic neuropathic pain. Pain 1995; 63: 55-64
• 35 Llinas RR, Ribary U, Jeanmonod D, Kronberg E, Mitra PP. Thalamocortical dysrhythmia: A neurological and neuropsychiatric syndrome characterized by magnetoencephalography. Proc Natl Acad Sci USA 1999; 96: 222-227
• 36 Berdok R.B., Levy R.M., Onibuton A. Deep Brain Stimulation for the Treatment of intractable pain. In: Batjer HH, Loftus CM. (Eds) Textbook of Neurological Surgery. Philadelphia; Lippincott Williams and Wilkins: 2003: 2673-2681
• 37 Nashold BS, Bullitt E, Friedman AH. The place of neurosurgery in the treatment of intractable pain. In: Swerdlow M, Charlton JE. (Eds) Relief of intractable pain. Elsevier Science Publishers BV (Biomedical Division); 1989: 305-327