Semirigid fixation of mandible and maxilla in orthognathic surgery: stability and advantages.

Although the use of rigid fixation of bony segments in orthognathic surgery has become a standard of care, the question remains, 'With use of rigid fixation has stability of common orthognathic surgical procedures improved?' Because of the problems with various methods of osteosynthesis for the osteotomies commonly used in orthognathic surgery, we have developed our own way of semirigid fixation method to stabilize the osteotomized fragments for bone healing with enough flexibility to avoid the problems arising from absolute rigid fixation. The purpose of this article is to review the existing data to determine whether our method of semirigid fixation yields enough short-term and long-term stability after orthognathic surgery procedures. The study was designed as a retrospective trial. A total of 23 patients with double jaw surgery and 12 patients with mandibular set back surgery were reviewed. Preoperative lateral cephalometric radiographs obtained 1 month before the surgery, early postoperative cephalometric radiographs obtained after intermaxillary fixation was opened and late postoperative cephalometric radiographs were evaluated. Pog-McNamara vertical (mm) was used to measure the anteroposterior movement of mandible. Facial axis (degrees) was used to measure the vertical movement of the anterior part of the mandible. A-McNamara vertical (mm) was used to measure the anteroposterior movement of maxilla. Maxillary height (degrees) was used to measure rotational movement of the osteotomized maxillary segment in vertical dimension. The raw data obtained from cephalometric analysis were evaluated by using the computerized statistical program SPSS version 11.5 for Windows. The differences in linear and angular measurements between time intervals were tested for statistical significance, using repeated measures analysis of variance. A value of P < 0.05 was considered significant. None of the patients had infection at maxillary osteotomy side. Unilateral local infection at osteotomy side was seen in only one patient after double jaw surgery. Condylar malpositioning was not observed in any of the patients. Although postoperative maxillaomandibular fixation with elastics was applied routinely to all patients for 15 days, none of the patients had complaint related with temporomandibular joint discomfort, such as pain, restricted joint motion, etc. There is significant difference in anteroposterior movement of mandible in all time intervals. In terms of facial axis, the differences at T1 and T2 and at T2 and T3 are significant, while the difference at T1 and T3 is not significant. There is significant difference in anteroposterior movement of maxilla in all time intervals. In terms of maxillary height, the differences at T1 and T2 and at T2 and T3 are significant, while the difference at T1 and T3 is not significant. Method of semirigid fixation with 2 plates for maxillary fixation and 2 screws for mandibular fixation provide enough stability after LeFort I and bilateral sagittal split osteotomy procedures where mainly anteroposterior linear displacements were performed. There was no significant clinical short-term or long-term relapse. Stability in rotational movements needs to be further evaluated.