INTERVERTEBRAL DISKS DEGENERATION: PRELIMINARY STUDIES ON PATHOLOGICAL FEATURES OF 42 SURGICAL SPECIMENS

Introduction: Intervertebral disks (ID) can exhibit normal aging changes and degenerative alterations leading to disk extrusion into the spinal canal. Materials and Methods: The authors report the histological features of n. 42 canine spinal surgery specimens comparing the observations between spinal level and breed - chondrodystrophoid (CD) and non chondrodystrophoid (NCD) dogs - by means of the Fisher test. Results: N.22 ID of CD and n. 20 ID of NCD, aging from 3 to12 years old, were evaluated. N. 34 samples were collected in thoracic/lumbar spine, and n. 8 in cervical spine. N. 40 samples were composed mainly by nucleus pulposus; two specimens showed lamellar structures of anulus fibrosus or cartilaginous laminae. Chondroid clusters in degenerate matrix occurred frequently (72.7% of CD e 45 % dei NCD). Chondroid metaplasia was detected in 80.5% of cases; it was significantly more frequent in CD (94.7%), but it was also present in 64.7% of NCD. Calcium deposits were observed in 100% of CD (80% I NCD). Granulation tissue and neovascularisation were detected in 71.43% of cases. In contrast with the literature (Hansen, 1952) the most interesting features were chondroid metaplasia and calcium deposits in NCD. Conclusion: A breed predisposition could induce the chondroid metaplasia, but probably a multifactorial aetiology induces disk degeneration. Further investigations are in progress in order to verify this hypothesis.