Facial asymmetries following unilateral condylar replacement. An experimental study in monkeys using metatarsal transplants.

The aim of the present study was to evaluate qualitatively and quantitatively the effect of metatarsal transplantation on the mandibular condylar region. Two series of experiments were performed in four groups of Rhesus monkeys, a fifth group served as a nonoperated control group. The surgical procedures involved either the condyle and part of the ramus or the condyle only. Following the postoperative observation period the skulls of the animals were examined macroscopically, measured anthropologically and measured indirectly on vertical cephalograms. A new method developed by the authors for description of facial asymmetries was used. In all of the operated animals well-functioning joint structures were revealed, though all experimental groups showed the classical deformation features. Continued growth of the transplant was observed in only one case. The facial asymmetries were described as angular deviations from the true symmetry axis. No significant difference between the transplant and the corresponding nontransplant groups was detected for the two kinds of resection performed. However a difference in the degree of asymmetry between the ramus resection group and the condylectomy group was seen. It is concluded that a metatarsal transplant does not prevent the development of facial asymmetry following plain condylectomy or resection of the posterior third of the ramus of the mandible including the condyle.