Three-dimensional changes in condylar position in skeletal class Ⅲ patients with mandibular deviation after bilateral sagittal split ramus osteotomy / 中华口腔医学杂志

Objective@#To investigage the three-dimensional changes in condylar position after bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class Ⅲpatients with mandibular deviation using cone-beam CT (CBCT).@*Methods@#Twenty-five skeletal class Ⅲ patients with mandibular deviation were included. The patients (12 males and 13 females, aged 19-25 years, average age 22.4 years) were treated in the Department of Orthodontics, Affiliated Stomatological Hospital, Nanchang University from October 2013 to March 2017. The patients were divided into T1, T2 and T3 groups (T1 group: CBCT taken within 1 week before operation; T2 group: CBCT taken within 1 week after operation; T3 group: CBCT taken 6-8 months after surgery). Three sets of image data of condyles on both sides (deviation side and contralateral side) were obtained. After the DICOM data collection, the software of Mimics 17.0 was used to perform three-dimensional reconstruction and condylar position measurements: the distance from the condylar top (CoT) to the standard horizontal plane (SHP), the middle sagittal plane (MSP) and the sella coronal plane (SCP) (CoT-SHP, CoT-MSP, CoT-SCP); the distance from the condylar center (CoC) to SHP, MSP and SCP (CoC-SHP, CoC-MSP, CoC-SCP); the angle from the condyle cella plane (CCP) to SHP, MSP and SCP (CCP-SHP, CCP-MSP, CCP-SCP); the angle from the condyle sagittal plane (CSP) to SHP, MSP and SCP (CSP-SHP, CSP-MSP, CSP-SCP) and the distance of the anterior, superior, posterior, medial, central and lateral joint space. One-way ANOVA and LSD-t test were used to compare the changes in condylar position at different periods (T1, T2, and T3).@*Results@#Within 1 week before operation on the deviation side, CoT-SHP [(2.5±1.3) mm], CSP-MSP (41.2°±8.4°) and the posterior joint space [(2.0±0.6) mm] were obviously increased (P<0.05), and CoT-SCP [(9.1±3.3) mm], CCP-MSP (78.2°±5.2°) were decreased significantly (P<0.05); on the contralateral side, CoT-MSP [(50.4±3.1) mm], CCP-MSP (80.6°±6.0°), the anterior joint space [(2.2±0.6) mm] and the medial joint space [(2.6±0.6) mm] were obviously increased (P<0.05), and CCP-SCP (11.4°±8.8°) were decreased significantly (P<0.05). Six to eight months after surgery, CoT-SHP [(2.2±1.0) mm] and the posterior joint space [(1.9±0.5) mm] on deviation side and CoT-SCP [(8.4±2.8) mm] on the contralateral side were increased significantly (P<0.05). No significant difference was found in other measurements (P>0.05).@*Conclusions@#The condylar position in skeletal class Ⅲ patients with mandibular deviation was asymmetrical. Within 1 week after the operation of BSSRO, the condyle on the deviation side was moved forward, downward and inward. Meanwhile, the condyle on the contralateral side was moved backward and outward. Six to eight months after surgery, the condylar position on both sides was gradually restored to the pre-operative condylar position.

Comparison of the Change in the Pharyngeal Airway Space, Tongue and Hyoid Bone Positions according to the Orthognathic Surgical Methods of Mandibular Prognathism

Initial Stability after Bilateral Sagittal Split Ramus Osteotomy Application in Patients with Mandibular Prognathism

Evaluation of Stability Following Two-Jaw Surgery

Soft tissue changes in skeletal class II patients treated with bilateral sagittal split osteotomy advancement surgery

The purpose of this study was to examine the soft tissue changes in skeletal class II patients after mandibular advancement by bilateral sagittal split ramus osteotomy (BSSRO). In Asian population, the incidence of skeletal class II malocclusion is lower than that of skeletal class III malocclusion unlike the caucasians. This study was conducted to figure out the ratio at which hard tissue and soft tissue changes after mandibular advancement by analyzing cephalograms of 13 patients that have undergone the mandibular advancement surgery. As a result, change ratios of Li, B', Pog' according to the movement of li, B, Pog were found to be 0.59, 1.06, 0.82. Also, vertical height of vermilion zone (Si-Vb) and lower lip and chin (Si-Me') were measured to evaluate vertical changes. Vermilion zone showed tendency to decrease by 1.02 mm on the average postoperatively, whereas vertical length of lower lip and chin showed tendency to increase by 3.57 mm on the average.

A Study on Bone-Contact to Inter-Segmental Length Ratio of Rigid Fixation Screws used in Bssro for Mandibular Setback

OBJECTIVE: To evaluate the ratio between bone-contact length and inter-segmental length of the rigid fixation screw used in bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. MATERIAL AND METHODS: Records of 40 patients with Class III malocclusion were selected. 20 of them had BSSRO, while the other 20 had BSSRO with maxillary LeFort I osteotomy. All of the patients had three noncompressive bicortical screws inserted at the gonial angle through transcutaneous approach. Two screws were inserted antero-posteriorly above inferior alveolar nerve and one screw was inserted below. The lengths of bone-contact and that of inter-segmental part were measured using cone-beam computed tomography. Ratio between these two measured lengths was calculated. RESULTS: Both bone-contact and inter-segmental lengths were longer in BSSRO group than in BSSRO with maxillary LeFort I osteotomy group. Ratio of bone-contact to inter-segmental length was lower in BSSRO group than in BSSRO with Lefort I group. Both bone-contact and inter-segmental lengths were longer at the antero-superior position than at the inferior position. However, their ratio showed little difference. CONCLUSION: This study suggest that stability of screws in BSSRO group was greater than in BSSRO with Lefort I group. Stability of screws at the antero-superior position was greater than at the inferior position. Ratio of bone-contact to inter- segmental lengths was 0.2 in average.

Changes in Tongue Position, Airway Width, Gonial Angle, Lower Facial Height after Bilateral Sagittal Split Ramus Osteotomy in Mandibular Prognathic Patients

INTRODUCTION: In patients with mandibular prognathism, Bilateral Sagittal Split Ramus Osteotomy(BSSRO) combined with orthodontic treatment reduces oral volume and influences tongue and other surrounding tissues. Purpose of this study was to analyze post-operative tongue position and airway dimension, as well as mandibular changes in vertical, horizontal, and angular dimensions. MATERIALS AND METHODS: Height of dorsum of tongue, width of airway, gonial angle and lower facial height of mandibular prognathic patients who visited Kangdong Sacred Heart Hospital from Jan. 2001 to Dec. 2006 were anaylzed via pre-operative and post-operative cephalograms. T-test was used to compare pre-operative and post-operative measurements. Also, correlations among pre-operative measurements of the patients were analyzed. RESULTS AND CONCLUSION: A significant correlation was shown between ANS-Xi-PM area and location of dorsum of tongue in pre-operative patients. A significant superior movement of tongue and decrease of airway width was observed in post-operative patients. Also the upper gonial angle decreased significantly.

Availability of autologous transfusion in bilateral sagittal split ramus osteotomy for mandibular prognathism

OBJECTIVE: Autologous transfusion is frequently used with orthognathic surgery. The necessity of autologous transfusion has begun to question alone in bilateral sagittal split ramus osteotomy. The aim of this study was to evaluate the availability of autologous transfusion. METHODS: The chart reviews of sixty patients who had undergone bilateral sagittal ramus osteotomy were done. The subjects were divided into two groups : In experimental group, 30 patients who autodonated 320ml in the preoperative 3 weeks actually received a transfusion in the postoperative 6 hours were included. In control group, 30 patients who underwent the same operation without preoperative donation and any other transfusion were included. Hemoglobin, hematocrit, and changes of these values in both groups were evaluated. RESULTS: 1. From postoperative 3 hours to postoperative 1 day, the increases of hemoglobin(0.8g/dL in experimental group, 0.2g/dL in control group) and hematocrit(0.3% in experimental group, 0.6% in control group) were not statistically significant between both groups. 2. From postoperative 1 day to postoperative 1 week, the increase of hemoglobin(0.6g/dL in experimental group, 0.3g/dL in control group) was not statistically significant between both groups. But the increase of hematocrit(2.5% in experimental group, 1.0% in control group) was statistically significant between both groups over the same period(hematocrit p=0.043). 3. On postoperative 1 week, the values of hemoglobin(12.3% in both groups) and hematocrit(35.6% in experimental group, 36.8% in control group) were not statistically significant between both groups. CONCLUSION : The autologous transfusion in surgery of just a little blood loss was not effective. The most results show that there is little availability of autologous transfusion according to changes of hemoglobin and hematocrit in bilateral sagittal split ramus osteotomy.

Facial nerve palsy after sagittal split ramus osteotomy in severemandibular prognathism: a case report

Comparative study of stability and relapse according to fixation method after bilateral sagittal split ramus osteotomies in mandibular prognathic patients

Postoperative positional change of condyle after bilateral sagittal split ramus osteotomy associated with mandibular asymmetry

Purpose: After the surgical correction with sagittal split ramus osteotomy, the position of the mandibular condyle in the glenoid fossa and the proximal segment of the mandible change because of bony gap between proximal and distal segment, especially in case of mandibular setback asymmetrically. In this study, positional changes in the condyle and proximal segment after BSSRO were estimated in the mandibular asymmetry patient by analyzing the in submentovertex view and P-A cephalogram for identification of ideal condylar position during surgery. Patients and Methods: The 20 patients were selected randomly who visit Dankook Dental Hospital for mandibular asymmetry. Bilateral sagittal split ramus osteotomy with rigid fixation was performed and P-A cephalogram and submentovertex view was taken at the time of preoperative, immediate postoperative, 3 month postoperative period. Results: Intercondylar length and transverse condylar angle was increased due to inward rotation of proximal segment and anteromedial rotation of lateral pole of condyle head. The condylar position had a tendency to return to the reoperative state and after 3 months return up to about half of the immediate post-operative changes, and all the results showed more changes in asymmetry patient and deviated part of the mandible. Conclusion: Based on all these results above, surgeon should make efforts to have a precise preoperative analysis and to have a ideal condylar position during rigid fixation after BSSRO.

A clinical study on the effects of bilateral sagittal split ramus osteotomy on the postoperative condylar positional changes in the mandibular prognathism

Analysis of short face tendency and it's determinant factors after bilateral sagittal split ramus osteotomy of mandibular prognathism

PURPOSE: The purpose of this study was to analyse the facial changes and factors contributing to then after bilateral sagittal split ramus osteotomy of mandibular prognathism. MATERIALS AND METHODS: Forty patients with Class III dental and skeletal malocclusion who were treated with bilateral sagittal split ramus osteotomy were reviewed. Frontal and lateral cephalometric radiographs were taken preoperatively, immediate postoperatively and more than six months postoperatively in each patient. After tracing the cephalometric radiographs, various parameters were measured. RESULTS: 1. Gonial angle at postoperative two days was decreased about 10.4 degrees than preoperatively and gonial angle at postoperative six months was increased about 6.8 degrees than postoperative two days. So, gonial angle at postoperative six months was decreased about 3.6 degrees than preoperative gonial angle. 2. Facial height postoperative two days was decreased about 0.8mm than preoperatively and facial height at postoperative six months was decreased about 0.7mm than postoperative two days. So, facial height at postoperative six months was decreased about 1.5mm than preoperative facial height. 3. Mandibular width postoperative two days was decreased about 1.0mm than preoperatively and mandibular width at postoperative six months was increased about 1.8mm than postoperative two days. So, mandibular width at postoperative six months was decreased about 2.8mm than preoperative mandibular width. 4. Amount of set back and mandibular plane angle were not influencing on relapse degree. CONCULSION: It is thought that bilateral sagittal split ramus osteotomy in mandibular prognathic patients is effective to improve long face and steep gonial angle. More prudent operation and careful postoperative management is required to maintain stable face postoperatively. Further research for soft tissue changes and factors which are related with relapse is needed.

Biomechanical analysis of mandibular bilateral sagittal split ramus osteotomy with bicortical screws internal fixation / 实用口腔医学杂志

Objective: To study the mandibular bilateral sagittal split ramus osteotomy (BSSRO) with bicortical screws rigid internal fixation(RIF) with the three-dimensional finite element method, and supply directions for clinic practice.Methods:CT scanned technology and the finite element software (Ansys) were used to establish the three-dimensional finite element model of BSSRO with bicortical screws RIF. The stress distribution of the mandible and the RIF and the displacement of split mandible were calculated under three kind of occlusion situation.Results:Under the same kind of occlusion situation, the stress and displacement of the split mandible with single upper screws fixation was higher than that with the reverse "L" screws fixation, the stress and displacement of the split mandible with 2.0 mm diameter screws fixation was higher than that with 2.7 mm diameter screws fixation. With the same kind of fixation method, the stress and the displacemen of the mandible under the incisor occlusion was the highest.Conclusion:The fixation distance, position, distribution angle of the bicortical screws all have effects on the fixation stability. The patient should avoid the incisor occlusion after the surgery.

Soft Tissue Change After Single Jaw(mandible) Surgery in Skeletal Class III Malocclusion / 영남의대학술지

The purpose of this study was to evaluate the amount and interrelationship of the soft and hard tissue change after mandibular setback surgery in skeletal Class III malocclusion. The sample consisted of 25 adult patient (12 male and 13 female) who had severe anteropostrior skeletal discepancy. These patient had received presurgical orthodontic treatment and surgical treatment which is bilateral sagittal split ramus osteotomy. The presurgical and postsurgical lateral cephalograms were evaluated. The computerized statistical analysis was carried out with SPSS/PC program. The result were as follows: 1. After mandibular bilateral sagittal split ramus osteotomy, lower facial soft tissue horizontal posterior changes were high significance value. but vertical soft tissue changes were low significance value. 2. After mandibular bilateral sagittal split ramus osteotomy, relative upper lip protrusion increased(p<0.01) and relative lower lip protrusion decreased(p<0.01) and lower facial soft tissue thickness increased(p<0.01).