Calcium pyrophosphate dihydrate deposition in degenerate lumbar discs

Calcium pyrophosphate dihydrate (CPPD) crystal deposition in lumbar intervertebral discs has been described, but its clinical significance remains unclear. The present study analyzed histological sections of lumbar discs that were obtained from patients undergoing anterior lumbar interbody fusion. Immunohistological staining was undertaken to identify neural elements and blood vessels. Patients with CPPD deposition were compared with a group without CPPD deposition undergoing the same operation. CPPD was found in 15.7% of investigated patients (12.6% of analyzed discs). Deposits were found in areas of the annulus and nucleus showing advanced degeneration. Two patterns were identified: one comprised sharply demarcated rounded deposits, while the other showed diffuse deposition of crystals. There was no association with ingrowth of vascular or neural tissue. Clinical data did not differ significantly in the two groups of patients. However, in all patients with CPPD deposition there was a history of trauma, previous surgery, or both. Isolated CPPD deposition in lumbar intervertebral discs appears to be an incidental finding that is not related to systemic diseases or general arthropathies.