Harry C. Schwartz

Distraction Osteogenesis for Temporomandibular Joint Reconstruction

PURPOSEnThis clinical study evaluated the use of transport distraction osteogenesis in reconstruction of the ramus-condyle unit (RCU) of the temporomandibular joint (TMJ).nnnPATIENTS AND METHODSnThirteen TMJ reconstructions were carried out in 12 patients. Diagnoses included tumors, trauma, ankylosis, and degenerative joint disease. The follow-up period has ranged from 7 to 59 months.nnnRESULTSnSuccessful distraction was carried out in all cases, with development of solid regenerate bone and an effective new articulation. There were no complications. A good functional level was achieved in all cases. One patient with bilateral rheumatoid arthritis has experienced ongoing degenerative changes in the reconstructed condyles, with reappearance of an anterior open bite. The occlusion has remained stable in all other cases.nnnCONCLUSIONSnDistraction osteogenesis is a promising treatment option in reconstruction of the RCU of the TMJ.

Bicortical-monocortical fixation of the sagittal mandibular osteotomy

Rigid internal fixation (RIF) has largely replaced wire osteosynthesis in stabilization of the bilateral sagittal split osteotomy (SSSO) of the mandibular ramus. RIF reduces or eliminates the requirement for maxillomandibular fixation (MMF), while preserving the stability of the surgical result. A decrease in the relapse tendency that is associated with the BSSO has been reported when RIF is used.’ Two methods of RIF are generally used in the BSSO: bicortical position screws2 and monocortical miniplates.’ The proponents of each technique cite certain benefits of the one and drawbacks of the other. The authors have developed a hybrid technique that draws on the benefits of each. It has been used for 5 years without technical difficulties or complications. Recent studies using a biomechanical model of the BSSO show that, within a physiologic range of loading, this hybrid technique produces stability that is comparable with or superior to that produced by conventional methods of RIF.4 Surgical Technique

Efficient Surgical Management of Mandibular Asymmetry

Although most cases of mandibular asymmetry are developmental, it can also result from congenital anomalies (eg, hemifacial microsomia), tumors, trauma, unilateral condylar hyperplasia, and temporomandibular joint (TMJ) ankylosis. Severe cases may require staging during growth. Early bone grafting or distraction osteogenesis can be useful when there is marked hypoplasia or if tissue is absent. After the completion of skeletal growth, milder cases or cases that have undergone previous staging procedures are managed with asymmetric mandibular osteotomies. Because asymmetric mandibular movements require that the teeth move toward one TMJ and away from the other (Fig 1), they pose a greater potential risk to the TMJs than other orthognathic movements. Experience has shown that small alterations in condylar position are well tolerated so long as torque is not applied during fixation (Fig 2). Condylar torque results in occlusal instability and TMJ dysfunction.