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Journal of Bone and Joint Surgery - British Volume, Vol 88-B, Issue 4,
554-557.
doi: 10.1302/0301-620X.88B4.17194 Copyright © 2006 by British Editorial Society of Bone and Joint Surgery Sympathetic afferent units from lumbar intervertebral discsT. Takebayashi, MD, PhD, Orthopaedic Surgeon1; J. M. Cavanaugh, MD, PhD, Professor2; S. Kallakuri, MS, Assistant Professor2; C. Chen, MD, Assistant Professor2; and T. Yamashita, MD, PhD, Professor and Chairman1
1 Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, South-1, West-16, Chuo-ku, Sapporo 060-8543, Japan. Correspondence should be sent to Dr T. Takebayashi; e-mail: takebaya{at}sapmed.ac.jp
To clarify the pathomechanisms of discogenic low back pain, the sympathetic afferent discharge originating from the L5-L6 disc via the L2 root were investigated neurophysiologically in 31 Lewis rats. Sympathetic afferent units were recorded from the L2 root connected to the lumbar sympathetic trunk by rami communicantes. The L5-L6 discs were mechanically probed, stimulated electrically to evoke action potentials and, finally, treated with chemicals to produce an inflammatory reaction. We could not obtain a response from any units in the L5-L6 discs using mechanical stimulation, but with electrical stimulation we identified 42 units consisting mostly of A-delta fibres. In some experiments a response to mechanical probing of the L5-L6 disc was recognised after producing an inflammatory reaction. This study suggests that mechanical stimulation of the lumbar discs may not always produce pain, whereas inflammatory changes may cause the disc to become sensitive to mechanical stimuli, resulting in nociceptive information being transmitted as discogenic low back pain to the spinal cord through the lumbar sympathetic trunk. This may partly explain the variation in human symptoms of degenerate discs. This article has been cited by other articles:
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