Comparison of Effects between Total Maxillary Setback Osteotomy and Anterior Maxillary Segmental Osteotomy on Nasolabial Morphology.

BACKGROUND: The authors aimed to compare the effects of total maxillary setback osteotomy (TMSO) and anterior maxillary segmental osteotomy (AMSO) on nasolabial morphology. METHODS: This retrospective clinical trial enrolled 130 patients undergoing maxillary surgery using TMSO or AMSO. Ten nasolabial-related parameters and nasal airway volume were measured preoperatively and postoperatively. The soft-tissue digital model was reconstructed using Geomagic Studio and Dolphin image 11.0. Statistical analysis was performed using IBM SPSS Version 27.0. RESULTS: A total of 75 patients underwent TMSO, and 55 underwent AMSO. Both techniques achieved optimal repositioning of the maxilla. Except for the dorsal nasal length, the dorsal nasal height, the length of the nasal columella, and the upper lip thickness, the remaining parameters were significantly different in the TMSO group. In the AMSO group, only the nasolabial angle, the alar base width, and the greatest alar width showed significant differences. There was a significant difference in the nasal airway volume for the TMSO group. The results of matching maps are consistent with the statistical results. CONCLUSIONS: TMSO has a more significant impact on both nose and upper lip soft tissues, whereas AMSO has a more significant impact on the upper lip and less on the nasal soft tissue. There is a significant decrease in nasal airway volume after TMSO, whereas AMSO showed less decrease. This retrospective study is helpful for clinicians and patients to understand the different changes in nasolabial morphology caused by the two interventions, which is essential for effective intervention and physician-patient communication. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Intraoperative condylar positioning techniques on mandible in orthognathic surgery.

PURPOSE: The surgical condylar displacement often resulted in relapse and serious symptoms of temporomandibular joint disorders (TMD) after orthognathic surgery. To minimize the displacement, numerous techniques have been proposed. To verify their accuracy in positioning and effectiveness in preventing post-operative TMD and relapse, we reviewed the literature related to intraoperative condylar positioning techniques on the mandible in this study. METHODS: The literature on condylar positioning techniques was reviewed with two charts, including the non-computer-assisted and the computer-assisted positioning methods. The pre- and post-operative alterations of condyles, the post-operative temporomandibular joint (TMJ) function and surgical relapse were analysed regarding the techniques. The clinical usage and characteristics were reviewed as well. RESULTS: A total of 22 articles, including 907 patients, have been reported since 2001. Nearly all methods reach a considerable positioning accuracy within the range of 1-2 mm and 1-2° from the pre-operative position. We ranked the accuracy of the methods from high to low: CAD/CAM CPDs > CAD/CAM titanium plate positioning > manual positioning > computer-assisted navigation systems > imaging positioning systems. Most skeletal class II and class III patients achieved great occlusion and had no TMJ dysfunction or relapse after condylar positioning. CONCLUSIONS: Both the non-computer-assisted and computer-assisted condylar positioning techniques reach considerable accuracy in locating the pre-operative condyle position and preventing TMJ dysfunction and surgical relapse. Different levels of surgeons and cases can benefit from multiple suggested positioning methods. Further research with large samples and long-term follow-up is worth looking forward to upgrading the current methods, improving the clinical utility and developing new positioning techniques.