The Possible Role of the Thoracolumbar Fascia in Non-Specific Low Back Pain

The available data on the innervation and sensory properties of the thoracolumbar fascia (TLF) are inconsistent and partly contradictory. In the present study, an evaluation of calcitonin gene-related peptide (CGRP) and substance P (SP)-containing free nerve endings was carried out in the rat and human TLF. In a separate series, the responsiveness of spinal neurons to painful stimulation of the TLF was studied. The data show that the TLF is a densely innervated tissue. The most superficial and deepest layers have particularly numerous CGRP-and SP-containing free nerve endings many of which are considered to be nociceptive. In electrophysiological recordings from dorsal horn neurons in lumbar spinal segments many cells responded to painful stimulation of the TLF. The proportion of neurons responding to input from the TLF rose significantly in animals with an experimental inflammation of the multifidus muscle. The data suggest that the TLF may play a role in painful conditions of the low back.