Healing following conventional and cryosurgical discoplasty in the monkey temporomandibular joint

A preliminary study of reconstruction of the monkey temporomandibular joint with autogenous tissues

PURPOSE

This study investigated the ability of autogenous pericranium-muscle and cranial bone to restore form and function of the temporomandibular joint (TMJ).

MATERIALS AND METHODS

A right TMJ discectomy, condylectomy, vertical ramus osteotomy with superior repositioning of the proximal fragment, and a cranial bone graft to the mandibular angle were performed in 12 cynomolgus monkeys. Clinical, histologic, and autoradiographic evaluation was done at intervals beginning at 3 days and continuing up to 78 weeks.

RESULTS

No significant postoperative sequela were identified in any of the monkeys. Jaw mobility and function were restored. Gross morphologic condylar changes were observed. The pericranium-muscle grafts did not differentiate into normal disc-like structures and a cartilage cap did not cover the condyle stump head.

CONCLUSIONS

The results of this study suggest that the previous TMJ function was restored. However, the histologic changes observed were consistent with advanced degenerative joint disease.

Surgical repair of defects in the rabbit temporomandibular joint disc: a comparison of various techniques

A study was designed to evaluate the effects of different types of repair (suture vs. graft), donor graft tissues (dermis vs. fascia), and methods of graft fixation (sutured vs. laser-assisted) on excisional defects of the rabbit TMJ disc made anterior to the retrodiscal tissue. Groups created to compare the different variables were assessed at 30 and 90 days postoperatively by macroscopic and histologic methods, microangiography, and mechanical strength testing. Without repair, all excisional defects of the disc failed to heal. Suturing of the reapproximated margins did not appear to promote healing or provide much strength beyond the properties of the suture material. Dermal grafts, fixed by suturing, induced healing by becoming incorporated into the disc, restoring discal continuity, and approximating normal disc strength. The use of laser-assisted tissue welding for dermal graft fixation was found to be inadequate and was subsequently abandoned. Fascial grafts could be fixed into position by both suture and laser-assistance, but consistently failed to exhibit successful transplantation and promote healing at the disc site.

Healing following condylar shave in the monkey temporomandibular joint

Condylar shaves were performed in monkeys, and the reparative process was studied by histologic and autoradiographic techniques. The condylar surface was found to repair mainly with fibrous connective tissue produced by cells derived from the underlying marrow spaces. The residual condylar cartilage did not play a significant role in this process.