Does Condylar Morphology Affect Maxillary Repositioning in Bimaxillary Orthognathic Surgery?

This study aimed to measure the association between condylar morphology and a measure of the maxillary centroid following bimaxillary surgery using mandibular-dependent splints. The study included skeletal Class III and Class II malocclusion patients, excluding those with facial asymmetry. Based on computed tomography imaging patients were characterized into normal or abnormal temporomandibular joint (TMJ) groups. A computer-aided design/computer-aided manufacturing splints were fabricated to reposition the maxilla in Le Fort I osteotomy. The primary outcome measure was the absolute differences between the maxillary centroid's the planned and actual postoperative positions calculated by superimposing computed tomography scans. The secondary outcome was the measure of other variations in linear and angular maxilla discrepancies. The demographic covariates included the age and sex of the patients. The operative covariates consisted of the dentofacial deformity and the planned movement of the maxilla. Seventy patients with skeletal maxillofacial deformities were included for analysis: 44 patients in the normal and 26 in the abnormal TMJ group. The average maxillary misalignment was 1.04±0.48 mm in the normal and 1.53±0.63 mm in the abnormal TMJ group (P<0.001). A statistically significant relationship existed between the discrepancies of the maxillary centroid and dentofacial deformity (η=0.656, P<0.001). These findings suggest an increased propensity for maxillary malposition in skeletal Class II patients. Furthermore, condylar morphology is a significant prognostic factor influencing maxillary repositioning errors in bimaxillary surgery with mandibular-dependent splints.

Study of Anatomical Changes of the Inferior Nasal Passage After Le Fort I Osteotomy With Superior Repositioning.

The relationship between postoperative morphological changes in the inferior nasal cavity and inferior turbinate after Le Fort I osteotomy remains unclear. This study aimed to investigate how the bone volume of the inferior turbinate affects contact with the inferior nasal cavity of patients who underwent superior repositioning. We evaluated the 3-dimensional relationship between the anatomical changes in the inferior nasal passage before and after surgery in 51 patients who underwent Le Fort I osteotomy with an elevation of >4.0 mm in the first molar. The soft tissue and bone volumes of the inferior turbinate and airway volume of the inferior nasal passage were calculated using Proplan CMF 3.0 and compared according to the size of the bone volume of the inferior turbinate. In addition, we reclassified the maxillary movements in the pitch direction and compared the results. The contact rates of the postoperative inferior nasal airway and the inferior turbinate in the large-bone group was 72.3% and that in the small-bone group was 40.0% in the χ2 test. The reduction in the inferior nasal passage volume was significantly greater in the large-bone group (pitch+) than in the small-bone group (pitch+). For patients with well-developed bony tissue of the inferior turbinate, caution is advised if the maxillary elevation is ≥4.0 mm, because the possibility of postoperative obstruction of the inferior nasal passages exist, which may lead to deterioration of nasal ventilation.

Postoperative stability of bioresorbable plates made of 85:15 poly (L-lactide-co-glycolide) in Le Fort I osteotomy.

OBJECTIVE: Recently, RapidSorb plates (DePuy Synthes) made of 85.15 poly (L-lactide-co-glycolide) have been used for orthognathic surgery; however, reports regarding their effectiveness are limited. We aimed to compare the postoperative stability of RapidSorb plates, RapidSorb combined with titanium (MOJ plates), and MOJ plates in patients who underwent Le Fort I osteotomy at Tokyo Medical and Dental University Hospital. STUDY DESIGN: The use of RapidSorb in the maxilla is a load-sharing application and therefore constitutes an approved indication. Discrepancies in the maxillary positions were measured using postoperative computed tomography data at 1 week and 1 year using the centroid method 3-dimensionally. Treatment with RapidSorb alone showed a more vertical discrepancy in the maxilla treatment with MOJ and RapidSorb+MOJ. The RapidSorb4 group was subdivided into 2 groups (under and over 1.0-mm) based on the change in the maxillary centroid. RESULTS: The bone gap at the lateral border of the piriform aperture was significantly larger in the over-1.0-mm group than in the 1.0-mm group. CONCLUSIONS: The fixation of RapidSorb alone is not appropriate in load-bearing and unstable applications but is not contraindicated for load-sharing indications. Fixation with RapidSorb combined with MOJ was clinically effective, with results similar to titanium plate-only fixation regarding postoperative stability.

Risk factors for postoperative facial swelling at 1 week after bimaxillary orthognathic surgery in Class III patients.

OBJECTIVE: To quantify facial swelling at 1 week after Le Fort I osteotomy and bilateral sagittal splitting ramus osteotomy in Class III patients and to identify factors contributing to the swelling based on clinical, morphologic, and surgical variables. STUDY DESIGN: Data from 63 patients were examined in this single-center, retrospective study. Facial swelling was quantitatively measured by superimposing computed tomography data taken in the supine position at 1 week and 1 year postoperatively and extracting the area of maximum intersurface distance. Age, sex, body mass index, thickness of subcutaneous tissue, and of masseter muscle, maxillary length (A-VRP), mandibular length (B-VRP), and posterior maxillary height (U6-HRP), surgical movement (ΔA-VRP, ΔB-VRP, ΔU6-HRP), drainage method, and usage of facial bandages were examined. Multiple regression analysis was performed using the above factors. RESULTS: The median swelling at 1 week postoperatively was 8.35 IQR (5.99-11.47) mm. Multiple regression analysis revealed three factors that were significantly associated with facial swelling: Use of postoperative facial bandages (P=0.03), masseter muscle thickness (P=0.03), and ΔB-VRP (P=0.04). CONCLUSION: Absence of a facial bandage, thin masseter muscle, and large horizontal mandibular movement are risk factors for facial swelling at 1 week postoperatively.

Comparison of magnetic resonance imaging findings in patients with intermittent closed lock and acute closed lock of the temporomandibular joint: a cross-sectional retrospective study.

OBJECTIVE: This study aimed to estimate the disc status in intermittent closed lock (ICL) and permanent closed lock (CL) temporomandibular disorders (TMDs) to test the hypothesis that the disc morphology and degree of anterior disc displacement affect the outcomes of these disorders. MATERIALS AND METHODS: All patients were clinically examined according to the Diagnostic Criteria for Temporomandibular Disorders Axis I protocol, and magnetic resonance imaging (MRI) confirmed ICL and CL. Fifty-six joints of 56 patients with ICL and 110 joints of 110 patients with acute CL with a locking period of less than 3 months were included. Patients with acute CL were further classified into two groups: those with CL that could be successfully manipulated (CLs group) and those with acute CL without the possibility of unlocking (CLu group). MRI was used to assess the degree of anterior displacement, lateral displacement of the disc, disc deformity, and joint effusion. MRI findings were compared among the joints in the ICL, CLs, and CLu groups. RESULTS: The degree of anterior displacement and disc deformity prevalence significantly differed among the ICL, CLs, and CLu groups. No significant intergroup differences were observed in terms of lateral displacement or joint effusion. CONCLUSIONS: These results suggest that anteriorly displaced discs and deformation of discs associated with TMD progression affect disc reducibility.

Risk factors of neurosensory disturbances at 1 year postoperatively after bilateral sagittal split osteotomy.

OBJECTIVE: To investigate morphologic and surgical risk factors causing neurosensory disturbances (NSDs) after bilateral sagittal split osteotomy (BSSO). STUDY DESIGN: A total of 237 patients (with 474 sides) who underwent BSSO were followed up for 1 year. Parameters examined included age, sex, asymmetry, mandibular movement direction, mandible cutting devices, split type, intraoperative exposure of the inferior alveolar nerve (IAN), contact between the IAN and screw, distance between mandibular canal and inner surface of the cortical bone (distance A), distance from lateral osteotomy to mental foramen (distance B), and NSD at 1 year postoperatively. RESULTS: NSD was observed in 62 (13.1%) sides of 51 patients. Exploratory factor analysis determined 4 factors (factor 1: distance A; factor 2: direction of mandibular movement; factor 3: distance B and cutting devices; factor 4: IAN exposure). Logistic regression analysis was performed using the above factors and age, sex, and asymmetry, making a total of 7 variables. Age, factor 1, and factor 4 were significant predictors of NSD. CONCLUSIONS: Advanced age, close distance between mandibular canal and inner surface of the cortical bone, and IAN intraoperative exposure are risk factors for NSD 1 year postoperatively. Cases at high risk for NSD must be treated with great care.

Study of Morphological Changes in the Inferior Turbinate After Le Fort I Osteotomy.

OBJECTIVE: There are cases in which patients complain of nasal obstruction after Le Fort I osteotomy, but the relationship with postoperative morphological changes in the nasal cavity, including the septum and inferior turbinate, is not clear. STUDY DESIGN: The authors evaluated the three-dimensional relationship of the morphological changes in the inferior turbinate before and after surgery in 84 patients who underwent Le Fort I osteotomy. Three classifications were made according to superior amount of maxillary movement at the base of nasal cavity. RESULTS: The high elevation group (4.0 mm or more) had 31 sides, the moderate elevation group had 93 sides, and the low elevation group (less than 2.0 mm) had 44 sides. The volume of inferior turbinate was 76.9 ± 12.8% of that before surgery in the high elevation group. The high- and moderate-elevation groups had significantly higher changes than the low elevation group, and the rate of contact between inferior turbinate and nasal cavity floor was 67.7%. CONCLUSIONS: After Le Fort I osteotomy, the volume of inferior turbinate tissue decreased in proportion to the amount of elevation of the maxilla. Although the soft tissue volume may be reduced due to adaptation of respiratory function, the inferior nasal passage was not completely ventilated in the high elevation group. If the elevation exceeds 4.0 mm counterclockwise with maxillary movement, it is necessary to consider the concomitant inferior turbinate resection because it may lead to nasal obstruction.

Changes in the condylar volume and skeletal relapse following orthognathic surgery in patients with dentofacial deformity: A retrospective study.

OBJECTIVE: To evaluate the relationship between the changes in condylar volume and maxillofacial skeletal morphology according to sex as well as the relationship between condylar volume reduction and skeletal relapse in patients who underwent orthognathic surgery. METHODS: Ninety-five patients were categorized into skeletal Class III, Class II, and facial asymmetry groups. Computed tomography scans taken preoperatively and at 1 year postoperatively were used for quantitative measurement. RESULTS: Postoperative condylar volume was reduced in both the Class II group and the deviated side of the asymmetry group. Both female and Class II deformity were significant predictors of postoperative reduction in the condylar volume. There was a significant correlation between skeletal relapse and postoperative change in condylar volume in the Class II group. CONCLUSION: Postoperative condylar resorption may be associated with preoperative maxillofacial skeletal morphology and sex and also with skeletal relapse in the Class II group.

Short-Term Stability After Segmental Le Fort I Maxillary Impaction Surgery With Mandibular Autorotation in Seven High-Angle Class II Patients: A Case Series.

PURPOSE: To retrospectively evaluate skeletal stability after Le Fort I maxillary impaction surgery and mandibular autorotation without bilateral sagittal split osteotomy (BSSO) in high-angle class II patients. MATERIALS AND METHODS: Seven female high-angle class II patients who underwent maxillary impaction surgery and mandibular autorotation without bilateral sagittal split osteotomy were included in this study. Surgical changes and relapse were measured on lateral cephalograms taken preoperatively and at 1 month, 6 months and 1 year postoperatively. RESULTS: The horizontal movement of the maxilla at point A was 5.8 ±â€Š3.3 mm backward, and the upward movement at the posterior nasal spine was 3.3 ±â€Š1.4 mm. The mean horizontal change at point A during the 1-year follow-up period was 0.1 ±â€Š0.2 mm, and the vertical change at posterior nasal spine was 0.2 ±â€Š1.3 mm, which were not statistically significant. The horizontal surgical change at point B was 4.0 ±â€Š1.8 mm forward and the vertical surgical change at point B was 4.7 ±â€Š1.8 mm upward. Postoperative relapse was 10.9% and 13.7% in the horizontal and vertical directions, respectively. CONCLUSIONS: Le Fort I maxillary impaction surgery with mandibular autorotation may be 1 of the suitable procedures for high-angle class II patients.

Does the amount of mandibular setback during bimaxillary surgery correlate with the degree of surgical relapse?

OBJECTIVE: The aim of this study was to investigate postoperative horizontal relapse of the mandible in terms of the effects of the magnitude of mandibular setback movement and ramus inclination after LeFort I osteotomy and sagittal split ramus osteotomy. STUDY DESIGN: A retrospective study of patients who underwent orthognathic surgery for mandibular prognathism was performed. Postoperative relapse at point B was analyzed with regard to the magnitude of mandibular setback and the ramus inclination. Serial cephalograms were used to measure surgical changes and evaluate postoperative relapse. RESULTS: Nineteen men and 31 women (mean age 23.1 years) were retrospectively enrolled. Mean surgical backward movement of the mandible at point B was 8.2 mm, mean ramus inclination was 3.56 degrees, and mean relapse 1 year postoperatively was 0.95 mm (11.6%). Horizontal relapse of the mandible was significantly correlated with the magnitude of mandibular setback (r = -0.52; P = .007) and ramus inclination (r = 0.48; P = .014). CONCLUSIONS: Increased horizontal mandibular relapse after bimaxillary surgery was associated with greater mandibular setback movement and increased proximal segment clockwise rotation. Mandibular relapse after bimaxillary surgery may be minimized via adequate control of intraoperative clockwise rotation of the proximal segment.

Association of Temporomandibular Joint Pain According to Magnetic Resonance Imaging Findings in Temporomandibular Disorder Patients.

PURPOSE: This study investigated the associations between magnetic resonance imaging (MRI) findings and pain in the temporomandibular joint (TMJ). MATERIALS AND METHODS: The study included 646 TMJs of 323 consecutive patients with temporomandibular disorders; of these, 222 (34.4%) had TMJ pain whereas 424 (65.6%) had no TMJ pain. MRIs were used to evaluate disc position, osteoarthritis, joint fluid, and bone marrow edema. Internal derangement was classified as normal, anterior disc displacement with reduction, and anterior disc displacement without reduction (ADDWOR); condylar morphology was classified as normal, moderate bony change, and severe bony change. The odds ratio (OR) for each MRI variable for nonpainful versus painful TMJs was computed using logistic regression analysis. RESULTS: Compared with joints with normal disc position, the OR of those with ADDWOR was 2.74 (P < .001) for TMJ pain. Similarly, compared with joints with normal condylar morphology, the OR of those with severe bony change was 4.62 (P = .02) for TMJ pain. In addition, the risk of TMJ pain increased by 2.37 in joints with joint fluid (P < .001) and by 2.34 in joints with bone marrow edema (P = .006). The risk of TMJ pain increased significantly with ADDWOR in combination with severe bony change, joint fluid, and bone marrow edema. CONCLUSIONS: These results suggest an association between TMJ pain and ADDWOR, severe bony change, joint fluid, and bone marrow edema. Thus, combining various MRI variables may improve the diagnostic accuracy of TMJ pain.

MRI changes in the temporomandibular joint following mandibular setback surgery using sagittal split ramus osteotomy with rigid fixation.

OBJECTIVES: This study examined the changes in temporomandibular joint dysfunction (TMD) symptoms and investigated the variations in the disc position, disc and condylar morphology following sagittal split ramus osteotomy (SSRO) with rigid fixation in patients with mandibular prognathism. Furthermore, the authors examined the correlation between mandibular setback and TMD symptoms. METHODS: The study included 24 Japanese patients with jaw deformities who were treated using bilateral SSRO and Le Fort I osteotomy. The clinical and magnetic resonance imaging findings in the temporomandibular joint were evaluated preoperatively and at three and six months postoperatively. RESULTS: The preoperative TMD symptoms were significantly associated with the prevalence of TMD symptoms at six months postoperatively. Anterior disc displacement improved in four joints with slight displacement and with no morphological change. There were no postoperative changes in condylar morphology. There was no significant correlation between mandibular setback and the postoperative TMD symptoms. CONCLUSION: Postoperative TMD symptoms may be influenced mainly by preoperative TMD symptoms rather than mandibular setback using SSRO with rigid fixation. Therefore, patients with TMD symptoms require physical examination and MRI for appropriate diagnosis preoperatively.

Temporomandibular joint intermittent closed lock: clinic and magnetic resonance imaging findings.

OBJECTIVE: This study was carried out to describe the clinical and magnetic resonance imaging (MRI) findings of patients with intermittent closed lock (ICL) of the temporomandibular joint (TMJ). STUDY DESIGN: This retrospective study included 58 joints with ICL and 526 joints without ICL as controls. We compared the MRI findings between the patients with and without ICL and investigated clinical and MRI finding of ICL patients. We divided ICL patients into 2 groups based on the treatment efficacy: effective and ineffective. RESULTS: There were significant differences in the prevalence of disk deformity between the joints with and without ICL. Masticatory muscle pain was observed in 41.7% of the effective group and in 80% of the ineffective group, respectively. CONCLUSIONS: These results suggest that there is a relationship among the onset of ICL and disk deformation. Masticatory musclepain was significantly observed in the ineffective group.