The Inverted Coronoid-Ramus Graft for Condylar Reconstruction

Abstract

The purpose of this article is to describe a creative, versatile technique for condylar reconstruction using autogenous mandibular bone. The technique has been used for reconstruction of small condyle and/or ramus defects (approximately 35 to 40mm in length) typically associated with condylar hyperplasia, condylar tumors, idiopathic condylar resorption, and failed reconstruction attempts.The technique involves excision of the ipsilateral coronoid process-mandibular ramus, inverting it and rotating the segment 180° along its horizontal axis to replace the excised condyle. The resultant graft simulates the morphology of the posterior aspects of the ramus and condyle and has been shown to resist resorption typical of endochondral bone grafts harvested from the rib or iliac crest. Grafting is carried out via vestibular and preauricular or endaural incisions. Four cases followed over a period of 3 to 40months (average, 21months) are presented. No adverse functional results, including ankylosis, removal of hardware or adverse remodeling, have occurred. A period of intermaxillary fixation is used because it is considered beneficial for intra-articular scarring of the subglenoid fossa pad (disc or retrodiscal tissue and fibrocartilage) and initial healing. Physical therapy has not been prescribed. The inverted coronoid graft is a versatile technique when virtual surgical planning is used to assess feasibility, as well as defect and graft dimensions; fabricate custom bone plate and drilling guides; and determine screw osteosynthesis sites. In general terms, a post-reconstruction opening of 35mm allows for adequate function and guards from contralateral symptomatic hypermobility given disparate right- and left-sided joint mechanics. In the cases described, a mean of 40.5mm was achieved; however, in 2 of these cases, this was measured with undesirable asymptomatic (preoperative) deviation to the ipsilateral side by greater than 4mm and by 6mm. The inverted coronoid graft technique reduces operative time, can be executed with few external scars, and reduces the number of operative fields.