Microscopic assessment of degenerated intervertebral disc: clinical implications and possible therapeutic challenge

To investigate a possible correlation between the histological and morphometric properties of herniated intervertebral disc, clinical and magnetic resonance imaging (MRI) characteristics of patients with lumbar disc degeneration (LDD).

Thirty six patients with LDD were clinically evaluated using Japanese Orthopaedic Association Score (JOAS), visual analogue scale (VAS) for pain in the lower back or in the pelvic limb; MRI-based classification according to Pfirrmann and Modic criteria. All patients underwent decompressive surgery and herniated intervertebral disc samples were histologically and morphometrically analyzed. Data obtained were statistically analyzed for bivariate and partial correlations.

The mean area size of chondron clusters correlated with age, JOAS (r=-0.385, p=0.032, tau=-0.279, rho=-0.380), Pfirrmann (r=0.505, p=0.002, tau=0.289, rho=0.365) and Modic (r=0.500, p=0.002, tau=0.331, rho=0.419) grading. There was a strong correlation between maximum area size of chondrons and JOAS (r=-0.427, p=0.009, tau=-0.299, rho=-0.430), Pfirrmann changes (r=0.432, p=0.008, tau=0.309, rho=0.388) and Modic endplate changes (r=0.444, p=0.007, tau=0.343, rho=0.434). JOAS correlated with both MRI classifications used for LDD.

The intervertebral disc cells tend to aggregate in clusters and the size of the chondrons from LDD correlated with JOAS, Pfirrmann and Modic. JOAS correlates with the imagistic evaluation systems Pfirrmann and Modic.