Removal of the articular fibrous layers with discectomy leads to temporomandibular joint ankylosis.

OBJECTIVE: The aim of this study was to investigate whether direct damage of the articular fibrous layers without condylar fracture, combined with discectomy, was enough to induce temporomandibular joint (TMJ) ankylosis. STUDY DESIGN: Bilateral TMJ surgery was performed in 8 growing sheep. Disk removal (DR) was performed in the lateral two-thirds on the control side, and disk and articular fibrous layers removal (DFLR) was performed in the lateral two-thirds on the experimental side. Four animals were sacrificed for each side at 1 and 3 months postoperatively. RESULTS: Fibrous ankylosis was achieved on the DFLR side in 2 of 4 sheep and fibro-osseous ankylosis in the other 2 sheep at 1 month after surgery. Fibro-osseous ankylosis developed on the DFLR side in 4 sheep at 3 months postoperatively. On the DR side, pathologic characteristics of TMJ osteoarthritis could be seen; however, no evidence of ankylosis was observed. The scores of TMJ ankylosis for the DR side were significantly lower than those for the DFLR side at different time points (P < .05). CONCLUSIONS: This study demonstrated that removal of articular fibrous layers combined with discectomy can lead to traumatic TMJ ankylosis.