Stability of unilateral sagittal split ramus osteotomy for correction of facial asymmetry: long-term case series and literature review

Bilateral sagittal split ramus osteotomy is considered a standard technique in mandibular orthognathic surgeries to reduce unexpected bilateral stress in the temporomandibular joints. Unilateral sagittal split ramus osteotomy (USSO) was recently introduced to correct facial asymmetry caused by asymmetric mandibular prognathism and has shown favorable outcomes. If unilateral surgery could guarantee long-term postoperative stability as well as favorable results, operation time and the incidence of postoperative complications could be reduced compared to those in bilateral surgery. This report highlights three consecutive cases with long-term follow-up in which USSO was used to correct asymmetric mandibular prognathism. Long-term postoperative changes in the condylar contour and ramus and condylar head length were analyzed using routine radiography and computed tomography. In addition, prior USSO studies were reviewed to outline clear criteria for applying this technique. In conclusion, patients showing functional-type asymmetry with predicted unilateral mandibular movement of less than 7 mm can be considered suitable candidates for USSO-based correction of asymmetric mandibular prognathism with or without maxillary arch surgeries.

Treatment of laterognathism of the mandible / 中华医学美学美容杂志

Objective To explore the treatment of laterognathism of the mandible.Methods Nineteen cases of laterognathism of the mandible were treated by Lefort Ⅰ osteotomy,sagittal split ramus osteotomy,genioplasty,anterior mandibular subapical osteotomy and prosthesis implantation,respectively,and their efficacy was evaluated and clinical experience summarized.Results The nineteen cases were followed up for average 12 months after the treatments and all the patients were satisfied with the surgical effects.All osteotomy lines healed well and there were no complications,such as root damage or neurotrosis.Conclusions The orthognathic procedure for laterognathism of the mandible should be selected according to the types and locations of asymmetry deformities.Anterior mandibular subapical osteotomy combined with mandibular cosmetic surgery for slight laterognathism of the mandible could achieve satisfactory results.

The change of frontal ramal inclination (FRI) after orthognathic surgery with laterognathism: posteroanterior cephalometric study

INTRODUCTION: To compare the change in frontal ramal inclination (FRI) in laterognathism after orthognathic surgery. MATERIALS AND METHODS: Twenty four patients (10 men, 14 women; mean age, 22.8+/-5.2 years) with minimal facial canting (< or =2 mm) and apparent menton deviation (5.9+/-2.4 mm) who had been operated on to correct facial asymmetry and skeletal CIII malocclusion, were selected. On a preoperative posteroanterior (PA) cephalogram, the FRI of the deviated side and non deviated side, L1 deviation amounts and menton deviation amounts were measured. The FRI differences between both sides were compared, and the correlations between the measured deviated elements and the FRI differences were analyzed. On a postoperative PA cephalogram, the shifting amount of L1, shifting amount of L7 and FRI of both sides were measured, and the correlations between the shifting elements and the change in FRI were analyzed. RESULTS: On the preoperative PA cephalogram, the FRI of the non deviated side was significantly greater than those of the deviated side. The differences in FRI, with a menton deviation amount showed a significant correlation. On the postoperative PA cephalogram, the FRI differences between the deviated and non deviated side were decreased significantly and mandibular transverse movement toward central position was noted. The mean shifting amounts of L7 were associated with the amount of change in the deviated side of FRI. CONCLUSION: Transverse shifting of the mandible through orthognathic surgery decreases the FRI difference, which showed laterognathism, and improves the facial contour.