Discogenic pain is associated with ingrowth of blood vessels and nerves, but uncertainty over the extent of ingrowth is hindering development of appropriate treatments. We hypothesise that adult human annulus fibrosus is such a dense crosslinked tissue that ingrowth Disc tissue was examined from 61 patients (aged 37–75 yrs) undergoing surgery for disc herniation, degeneration or scoliosis. 5 µm sections were stained with H&E to identify structures and tissue types. 30 µm frozen sections were examined using confocal microscopy, following immunostaining for CD31 (an endothelial cell marker), PGP 9.5 and Substance P (general and nociceptive nerve markers, respectively). Fluorescent tags were attached to the antibodies. ‘Volocity’ software was used to calculate numbers and total cross-sectional area of labelled structures, and to measure their distance from the nearest free surface (disc periphery, or annulus fissure).Introduction
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Severe ‘discogenic’ back pain may be related to the ingrowth of nerves and blood vessels, although this is controversial. We hypothesise that ingrowth is greater in painful discs, and is facilitated in the region of annulus fissures. We compared tissue removed at surgery from 22 patients with discogenic back pain and/or sciatica, and from 16 young patients with scoliosis who served as controls. Wax-embedded specimens were sectioned at 7μm. Nerves and blood vessels were identified using histological stains, and antibodies to PGP 9.5 and CD31 respectively.Introduction
Methods