Condylar Sag Research Articles

The use of ultrasound to determine the position of the mandibular condyle

A randomized, single blind study of 20 patients examined the accuracy of ultrasound in establishing the position of the mandibular condyle in relation to the glenoid fossa. The sonographic technique is described. The temporomandibular joint was imaged sonographically with the patients in an open- and a closed-mouth position as a model for condylar sag and proper condylar seating, respectively, during mandibular ramus osteotomy procedures. One radiologist identified condylar position correctly in 38 of 40 still ultrasound images, with a sensitivity and a specificity of 95%. During real time ultrasound examination, it is possible to visualize varying degrees of condylar movement in relation to the glenoid fossa. The results of this study support the potential use of ultrasound as an adjunct to mandibular orthognathic surgery.

Correction of condylar displacement following intraoral vertical ramus osteotomy

Fifteen patients who demonstrated condylar sag after intraoral vertical ramus osteotomy for the correction of mandibular proganthism were treated nonsurgically to establish the desired postoperative occlusion. A mean inferior displacement of 3.33 mm and anterior displacement of 2.18 mm were observed tomographically after surgery. Postoperatively, a geometric splint was constructed to compensate for the magnitude of condylar displacement and was used to replace the original splint to hold the distal segment in an overcorrected position. Skeletal fixation was maintained for 5 to 6 weeks. Tomographic evaluation of the temporomandibular joint (TMJ) during maxillomandibular fixation showed a slight superior (1.03 mm) and posterior (0.51 mm) movement of the condyle in the fossa. After release of fixation and removal of splint, a further superior (2.05 mm) and posterior (1.01 mm) repositioning of the condyle was observed. This later movement correlated with the placement of light class III elastic traction to seat the condyles into the glenoid fossae and establish a class I occlusion. Temporomandibular joint tomograms confirmed complete seating of the condyles in the fossa and lateral cephalograms demonstrated a corresponding change in the position of the mandible to the desired postoperative position. This technique has been effective in preventing postoperative malocclusion resulting from condylar sag.

Condylar positioning in orthognathic surgery

The sag&al split ramus osteotomy of the mandible is a versatile surgical procedure that can be used to correct many skeletal and functional maxillofacial deformities. However, authors in the past 15 years have addressed the problems associated with the improper postoperative position of the proximal or condylar segment of the mandible.‘-l2 The general concern has been that the proximal segment should be maintained in its correct anatomic and preoperative position following the surgical positioning of the distal, or tooth bearing, segment and fixation of the mandible. Failure to correctly position the proximal segment can result in a built-in relapse potential, loss of the gonial angle, condylar sag, pain and dysfunction of the temporomandibular joint, and functional impairment of the masticatory system.‘,‘.5-7.9.12-14 Several authors have proposed techniques and devices by which the correct position of the proximal segment can be maintained both during fixation and postoperativity. 3*4,9~10~13-16 None of these techniques, however, can be used in procedures involving both the mandible and maxilla. These techniques also fail to provide for maintenance of the position of the proximal segment in three dimensions during fixation of the bony segments. Luhr recently described a method using an “L” or “T” shaped miniplate adapted to the lateral ascending ramus and to the maxillary arch wire in mandibular surgery. l7 In this article Luhr also de

A comparison between superior and inferior border wiring techniques in sagittal split ramus osteotomy

The proper alignment of the proximal and distal segments after the sagittal split ramus osteotomy (SSRO) has been a major concern since this procedure was first performed. Because of this problem, a comparison was made between a superior border wiring technique and an inferior border wiring technique. This involved the preoperative and postoperative lateral cephalograms of 35 patients from the Department of Oral Surgery at the Medical College of Georgia who received a SSRO with advancement. Nineteen patients received an inferior border wire and 16 patients received a superior border wire. The areas studied were anterosuperior rotation of the proximal segment, increase in gonial angle, and condylar sag. A cephalometric evaluation and a computer analysis were performed. It was found that the inferior border wiring technique produces a statistically significant lesser amount of anterosuperior rotation of the proximal segment and less increase in gonial angle than the superior border wiring technique. Because of these findings, it was felt that the inferior border wiring techniques produce less displacement of the proximal segment in the SSRO advancement.

Pin fixation of the proximal segment in intraoral oblique subcondylar osteotomy of the mandible

Condylar sag has been a problem following intraoral oblique subcondylar osteotomy of the mandible when the proximal segment has not been fixed. A simple method of proximal segment fixation that allows for accurate condylar positioning has been presented.