Experimental study on mechanism of vertebral osteophyte formation

OBJECTIVE: The purpose of this experimental stud y was to explore the mechanism of the vertebral osteophyte formation. METHODS: An experimental model of cervical spondylosis in rabbits was established by resection of the cervical supraspinous and interspino us ligaments and detachment of the posterior paravertebral muscles from cerv ical vertebrae. Because of individual difference, the natural development proced ure of the vertebral osteophyte formation could be seen with a microscope by dyn amic observation. RESULTS: The cartilage end-plate was divided into a growth car tilage layer and an articular cartilage layer. Vertebrae and discs from the 3-m onth control group rabbits showed normal structure. The changes of cartilage pla tes from the 3-month experimental group and the 8-month control group animals showed proliferation in peripheral articular cartilage. The osteophytes from the 8-month experimental group animals could be seen. The osteophyte obviously ari sed from proliferation, calcification and ossification of the peripheral articul ar cartilage. CONCLUSIONS: The vertebral osteophyte arises from proliferation of peripheral articular cartilage which undergoes cartilaginous osteophyte, and then changes into bony osteophyte through an endochondral calcification and ossification.