• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.3
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• pp.156-164
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• 2015

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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.4
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• pp.249-256
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• 2021

Objectives: The purpose of this study was to evaluate the postoperative anteroposterior stability and improvements in facial asymmetry after performing LeFort I osteotomy in the maxilla, sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) in the mandible, and lateral corticectomy on the IVRO side. Materials and Methods: From July 2009 to October 2018, a retrospective analysis was performed on 11 subjects. Lateral cephalometric radiograph was performed preoperatively (T0), postoperatively (T1), and at 12 months of follow-up (T2), and the B point distance was measured. Posteroanterior cephalometric radiograph was performed preoperatively (S0) and at 12 months of follow-up (S1) and was used to measure five indicators (Ag angle, M-Ag, Co-Ag, Co-Me, and Ag-Me) of facial asymmetry. Results: The B point distances for T0 and T1 were significantly different (P=0.007), whereas those for T1 and T2 were not significantly different (P=0.1). In addition, there was a significant difference between the B point distances of T2 and T0 (P=0.026). Comparison of the facial asymmetry indicators before and after surgery showed a significant difference for all indicators between S0 and S1: the P-values of Ag angle, M-Ag, Co-Ag, Co-Me, and Ag-Me were 0.003, 0.003, 0.008, 0.006, and 0.004, respectively. The Z value was based on negative ranks. Conclusion: There was no significant difference in the B point distances from postoperation to the 12-month follow-up. However, there were significant differences in all five indicators related to facial asymmetry before and after surgery. The values for the five indicators of facial asymmetry all increased postoperatively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.5
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• pp.359-367
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• 2004

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 preoperative 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.

• Journal of Oral Medicine and Pain
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• v.38 no.3
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• pp.255-260
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• 2013

Bilateral sagittal split ramus osteotomy(BSSRO) of the mandible is an essential and commonly used procedure to correct dentofacial deformities and malocclusion. The possible complications associated with BSSRO include inferior alveolar nerve injury, bleeding, temporomandibular disorder, unfavorable fractures, and clinical relapse. The incidence of facial nerve palsy after orthognathic surgery recently reported is 0.1%. The probable etiologies have included facial nerve compression, complete or incomplete nerve transection, nerve traction, and nerve ischemia from anesthetic injection. Postoperative facial palsy is one of the most serious complications because it reduces the quality of life and significantly reduces social interaction. The case of a 24-year-old patient who underwent bilateral sagittal split ramus osteotomy is described. The medical records and postoperative photographs were reviewed in detail to collect information on the clinical course, treatment, and outcomes.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.2
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• pp.190-197
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• 2011

The management of mandibular prognathism was revolutionized by the advent of the of sagittal split ramus osteotomy (SSRO) technique as described by Obwegesser and Trauner in 1957. Facial nerve palsy following SSRO is a rare but serious problem. In the event of post-operative facial palsy, careful clinical and neurophysiological investigations such as a nerve condunction test for facial function is mandatory. The authors examined patients with facial palsy following SSRO. Patients recovered after 3~4 months and we had performed clinical examinations with electromyography and nerve conduction tests during follow-up period.

• Archives of Craniofacial Surgery
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• v.18 no.1
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• pp.65-70
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• 2017

A 25-years-old woman with mandibular prognathism underwent a mandibular setback by way of mandibular sagittal split ramus osteotomy (MSSRO). After 2 days of operation, she developed difficulty of closing her right eye. The blink reflex test and motor nerve conduction study of the right orbicularis oris muscle were revealed right facial neuropathy of unknown origin and House-Brackmann facial nerve grading system (HBFNGS) grade V. For treatment, we initially prescribed oral prednisolone and nimodipine including physical therapy. The samples consisted of 11 facial nerve palsy patients caused by MSSRO and were analysed about onset of facial nerve palsy, postoperative HBFNGS, final HBFNGS, treatment method and recovery time. At 10 weeks of treatment of nimodipine, she had completely regained normal function (HBFNGS grade I) of the right facial nerve. The clinical results lead to assume a fast recovery of facial nerve function by the nimodipine medication, whereas average time of recovery is 16.32 weeks in references. Despite of the limited one patient treated, the result was very promising with respect to a faster recovery of the facial nerve function. Considering the use of nimodipine treatment for peripheral facial nerve palsy following a surgical approach with an anatomically preserved nerve can be recommended.

• The Journal of the Korean dental association
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• v.55 no.8
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• pp.537-540
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• 2017

BSSRO (bilateral sagittal split ramus osteotomy) is frequently performed to correct dentofacial deformity and malocclusion. Among its complications the incidence of post-operative facial nerve palsy is very rare, but it is one of the most serious complications. The case of a 21-year-old male patient who underwent facial nerve palsy after BSSRO is described. After surgical intervention and conservative therapy, the patient recovered his facial nerve function successfully.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.5
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• pp.185-191
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• 2014

Purpose: Although there have been several studies of reduced airway space after mandibular setback surgery using the sagittal split ramus osteotomy technique, research on the risk factors for changes of the airway space is lacking. Therefore, this study was performed to examine airway changes and the position of the hyoid bone after orthognathic surgery, and to assess possible risk factors. Methods: In this retrospective study, 50 patients who underwent posterior displacement of the mandible by the bilateral sagittal split ramus osteotomy technique were included. Changes of the position of the hyoid bone and the airway space were analyzed over various follow-up periods, using cephalometric radiography taken preoperatively, immediately after surgery, eight weeks after surgery, six months after surgery, and one year after surgery. To identify risk factors, multiple regression analysis of age, gender, body mass index (BMI), posterior mandibular movement, and the presence of genioplasty was performed. Results: Inferor and posterior movement of the hyoid bone was observed postoperatively, but subsequent observations showed regression towards the anterosuperior aspect. The airway space also significantly decreased after surgery (P<0.05), and increased slightly up until six months after surgery. The airway space significantly decreased (${\beta}=0.47$, P<0.01) as the amount of mandibular setback increased. However, age, sex, BMI, and presence of genioplasty were not associated with airway reduction. Conclusion: The amount of mandibular set back was significantly associated with postoperative reduction of airway space. It is necessary to establish a treatment plan considering this factor.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.5
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• pp.524-529
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• 2007

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.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.1
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• pp.35-40
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• 1999

Recently, sagittal split ramus oseotomy and intraoral vertical ramus osteotomy have been commonly performed for the correction of mandibular prognathism, occurred to abundant oriental people. Many authors have studied the soft tissue change after orthognathic surgery, especially between mandibular hard tissues and soft tissue of lower lip, but the study of upper lip change is comparatively little. Therefore, we studied the 12 patients, operated only sagittal split ramus osteotomy without genioplasty or maxillary osteotomy in department of oral and maxillofacial surgery, Hanyang university hospital from 1996. 1. 1. to 1998. 7. 20. Preoperative and postoperative cephalometric view was measured to know the change of upper lip position and shape after mandibular setback. The result were obtained as follows. 1. The ratio of upper lip change amount to lower incisor horizontal movement was 15.1%. 2. The ratio of lower facial profile between Sn-Stm and Stm-Mes was changed from 1 : 2.352 to 1 : 2.069 after operation. 3. Post-operative upper lip was flattened 72.4% compared with pre-operative one. 4. The vermilion zone of the upper lip increased 56 % horizontally, 5.8% vertically after operation. 5. The vermilion zone ratio of the lower lip to the upper lip was changed from 1 : 1.253 to 1 : 1.348. 6. The distance between esthetic line and Ls was changed from -3.958mm to -1.15mm.