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Purpose To clarify the significance of Modic changes, bony endplate lesions, and disc degeneration as predictors of chronic low back pain (LBP) during 1-year follow-up. Methods 49 patients with severe, non-specific, chronic LBP, and Modic 1 lesion (M1) were prospectively studied with MRI and questionnaire. Changes in grade of disc degeneration, severity of Modic changes, Schmorl lesions, and bony endplate irregularities were evaluated and changes assessed in LBP intensity on numeric rating scale 0-10 and severity with Oswestry disability index 0-100 (ODI). Association between change in MRI findings and symptoms was computed using generalized estimating equations analysis.Results Although pain decreased in most patients during 1-year follow-up, it increased or persisted in 36 %. Change in M1, M2, bony endplate lesions, and signal intensity (SI) and height of the disc associated with change of pain intensity, while change in M1, bony endplate lesions, and disc height associated with change of ODI. Not only persistent M1s, increasing bony endplate lesions, decreasing disc height, and M2s, but also new M2s predicted persistence of pain, while decrease of M1s and SI of the disc and increase of size of M2s predicted decrease of pain. Changes in disc bulges did not associate with pain. Conclusions In patients with chronic non-specific LBP, persisting M1, decreasing disc height, and increasing bony endplate lesions associated with persisting pain while decrease of SI of the disc with decrease of pain. Such changing MRI findings in the same disc space have earlier been shown to progress abnormally fast. They may be signs or biomarkers of a prolonged pain causing, deforming degenerative process, and should lead to considering early intervention or specific treatments to affect that process.

Endplate deformation, decreasing disc height and change of disc signal intensity appear essential features of accelerated degenerative process associated with M1.

BackgroundThe association of Modic changes (MC) with low back pain (LBP) is unclear. The purpose of our study was to investigate the associations between the extent of Type 1 (M1) and Type 2 (M2) MC and low back symptoms over a two-year period.MethodsThe subjects (n = 64, mean age 43.8 y; 55 [86%] women) were consecutive chronic LBP patients who had M1 or mixed M1/M2 on lumbar spine magnetic resonance imaging (MRI). Size and type of MC on sagittal lumbar MRI and clinical data regarding low back symptoms were recorded at baseline and two-year follow-up. The size (%) of each MC in relation to vertebral size was estimated from sagittal slices (midsagittal and left and right quarter), while proportions of M1 and M2 within the MC were evaluated from three separate slices covering the MC. The extent (%) of M1 and M2 was calculated as a product of the size of MC and the proportions of M1 and M2 within the MC, respectively. Changes in the extent of M1 and M2 were analysed for associations with changes in LBP intensity and the Oswestry disability index (ODI), using linear regression analysis.ResultsAt baseline, the mean LBP intensity was 6.5 and the mean ODI was 33%. During follow-up, LBP intensity increased in 15 patients and decreased in 41, while ODI increased in 19 patients and decreased in 44. In univariate analyses, change in the extent of M1 associated significantly positively with changes in LBP intensity and ODI (beta 0.26, p = 0.036 and beta 0.30, p = 0.017; respectively), whereas the change in the extent of M2 did not associate with changes in LBP intensity and ODI (beta -0.24, p = 0.054 and beta -0.13, p = 0.306; respectively). After adjustment for age, gender, and size of MC at baseline, change in the extent of M1 remained significantly positively associated with change in ODI (beta 0.53, p = 0.003).ConclusionChange in the extent of M1 associated positively with changes in low back symptoms.

In anulus fibrosus samples from macroscopically normal discs, a general marker for nerve endings can be found at a depth of a few millimeters, whereas neuropeptide markers show nerves only in the outermost layers of the anulus fibrosus. This absence of demonstrable nerves in deeper anulus fibrosus in normal discs is probably not a methodologic artifact, because blood vessels have also been demonstrated only at the disc surface. It is, however, possible that neuropeptide nerves also penetrate to a depth of a few millimeters, but that methodologic limitations permit the visualization of only the neuropeptide nerves closest to the disc surface. The results of the present study lend support to previous suggestions that, except at the surface, a normal intervertebral disc is almost without innervation.

Nerves exhibiting substance P-like immunoreactivity were demonstrated in the human periosteum. A network of nerves showing substance P-like immunoreactivity was seen in the periosteum, while finer strands of immunoreactive nerve fibers were present immediately beneath the surface of the periosteum. Enkephalin-like immunoreactivity was also studied but could not be demonstrated. Substance P has previously been suggested to be involved in the mediation of the sensation of pain. The clinically observable marked pain sensitivity of periosteal tissue might be explained by the peptidergic nerves described in this paper.

Cytological analysis of material aspirated from the effusion which occasionally develops around a polyglycolic acid (PGA) osteosynthesis implant showed a predominance of inflammatory monocytes and in particular lymphocytes. In order to discover whether PGA implants are immunologically inert, density gradient-isolated peripheral blood mononuclear cells were cultured in 0.2 ml of 10% delta FCS-RPMI 1640 culture medium supplemented with 10 mg PGA. Phytohaemagglutinin (PHA) lectin, a purified protein derivate of tuberculin (PPD) antigen and culture medium alone were used as positive and negative controls. We studied lymphocyte activation kinetics on days 0, 1, 3 and 5. Major histocompatibility complex locus II antigen (MHC locus II antigen) and interleukin-2 receptor (IL-2R) expression were analysed using the avidin-biotin-peroxidase complex (ABC) method and lymphocyte DNA synthesis by using 3H-thymidine incorporation and beta-scintillation counting. Especially on culture days 0 and 1, lymphocytes and monocytes were seen by light microscopy to be attached to PGA particles. However, our results show no PGA-induced lymphocyte DNA synthesis, but PGA-induced MHC locus II antigen and IL-2R activation marker expression was seen, greater than in negative controls, but less than that seen in PPD antigen driven lymphocyte response. This suggests that PGA is an immunologically inert implant material, but it does seem to induce inflammatory mononuclear cell migration and adhesion, leading to a slight non-specific lymphocyte activation. This activation is lower than that seen in mitogen and antigen-driven lymphocyte responses.