• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.4
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• pp.167-173
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• 2018

Objectives: Classification of the degree of postoperative nerve damage according to contact with the mandibular canal and buccal cortical bone has been studied, but there is a lack of research on the difference in postoperative courses according to contact with buccal cortical bone. In this study, we divided patients into groups according to contact between the mandibular canal and the buccal cortical bone, and we compared the position of the mandibular canal in the second and first molar areas. Materials and Methods: Class III patients who visited the Dankook University Dental Hospital were included in this study. The following measurements were made at the second and first molar positions: (1) length between the outer margin of the mandibular canal and the buccal cortical margin (a); (2) mandibular thickness at the same level (b); (3) Buccolingual $ratio=(a)/(b){\times}100$; and (4) length between the inferior margin of the mandibular canal and the inferior cortical margin. Results: The distances from the canal to the buccal bone and from the canal to the inferior bone and mandibular thickness were significantly larger in Group II than in Group I. The buccolingual ratio of the canal was larger in Group II in the second molar region. Conclusion: If mandibular canal is in contact with the buccal cortical bone, the canal will run closer to the buccal bone and the inferior border of the mandible in the second and first molar regions.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.3
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• pp.232-240
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• 2008

Purpose: This study was performed to evaluate transverse changes of proximal segment after bilateral sagittal split ramus osteotomy (BSSRO) using 3-D CT in mandibular prognathism. Patients and methods: Twenty-two patients who underwent BSSRO for mandibular set-back in class III malocclusion without facial asymmetry were examined. Miniplates were used for the fixation after BSSRO. Facial CT was taken before and after BSSRO within 3 months. Frontal-ramal inclination (FRI), inter-gonial width (IGW) and intercondylar width (ICW) were measured in 3-D CT images using V-works $4.0^{TM}$ program. Student t-test was used to compare the changes between pre- and post-operative measurements using SPSS 10.0 program. Results: 1. Mean peroperative FRI value ($12.87{\pm}3.43^{\circ}$) was slightly increased to postoperative value ($14.13{\pm}3.72^{\circ}$) (p < 0.05). The average FRI increased 10.42% and the range was from $-2.46^{\circ}$ to $3.34^{\circ}$. 2. Mean peroperative IGW ($99.01{\pm}5.36$) was slightly decreased to postoperative IGW ($96.51{\pm}5.88mm$) (p < 0.05). The average IGW decreased 2.52 % and the range was from $-6.61^{\circ}$ to 0.91 mm. 3. Mean preoperative ICW ($125.01{\pm}5.30mm$) was slightly decreased to postoperative ICW ($125.40{\pm}5.45mm$) (p < 0.05). There is no significant difference between pre- and post-operative ICW. 4. There was significant correlationship between FRI difference and IGW difference (p < 0.05). Conclusions: These results indicate that the lower ramus of the proximal segment is moved inward after BSSRO procedure for mandibular set-back.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.2
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• pp.141-148
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• 2010

The bilateral sagittal split ramus osteotomy (BSSRO) is preferred method of surgical correction for mandibular prognathism, retrognathism and asymmetry. This technique performed from primarily an intraoral incision to avoid a scar. After forward movement of the distal segment of the mandible, healing of bone by primary or secondary intention is easily accomplished through large areas of cancellous bony overlap. When rigid fixation is used for the BSSRO, it is possible to open the mouth during the immediate post-operative period because it promotes the healing process. Although this surgical procedure has been well-documented, the incidence of postoperative trigeminal neurosensory disorder in the region of the inferior alveolar nerve and the mental nerve remains one of the major complication. However, evaluation of objective methods for sensory recovery patterns is insufficient although most patients find their sensory return. Neurometer electrodiagnostic device performs automated neuroselective sensory nerve conduction threshold evaluation by determining current perception threshold (CPT) measures. The purpose of this study was to evaluate the sensory recovery patterns of inferior alveolar and mental nerve over time. Nerve examination with a neurometer was performed in 30 patients undergoing the BSSRO at pre-operative, post-operative 1-, 2-, 4- week, and 2-, 3-, 4-, 5-, 6- month follow-up visits after the osteotomy to compare the differences of nerve injury and recovery patterns after the BSSRO with or without genioplasty and sensory recovery patterns associated with the kind of nerve fiber.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.2
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• pp.100-105
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• 2012

Purpose: In general, the surgical treatment for mandibular retrognathism is represented by two methods, distraction osteogenesis (DO) and mandibular osteotomy surgery. The DO is mostly preferred when the degree of advancement of mandible is large. However, the postoperative stability of mandibular advancement using DO have not been actively investigated. Therefore, in the present study we have compared the postoperative stability between DO and bilateral sagittal split ramus osteotomy (BSSRO) in mandibular retrognathism. Methods: Seven patients who had been treated by DO and thirteen patients with BSSRO were included in this study. Serial lateral cephalograms were analyzed by manual tracing and the amount of the mandibular elongation was measured. To evaluate the postoperative stability, positional changes of the condylar position and B point were analyzed. Results: Mean amount of mandibular advancement was $6.51{\pm}3.57mm$ for BSSRO group and $12.43{\pm}4.35mm$ for DO group, respectively. There was no significant difference in age between the two groups (P>0.05). Mean follow up periods were 10.77 months for BSSRO group and 11.28 months for DO group, respectively. After mandibular advancement, mean positional changes in the condyle were $0.56{\pm}1.43mm$ horizontally and $0.72{\pm}1.61mm$ vertically for BSSRO group and $0.53{\pm}1.56mm$ horizontally and $0.56{\pm}1.75mm$ vertically for DO group, respectively. Mean change of distance from B point to Y-axis was $-1.76{\pm}0.83mm$ for BSSRO group and $-2.14{\pm}1.82mm$ for DO group, respectively. According to the condylar position and B point, there were no significant differences in postoperative stability between the two groups (P>0.05). Conclusion: There was no significant difference in postoperative stability between DO and BSSRO group according to condylar position and B point. Based on the results of the present study, it is hypothesized that DO would be a good treatment choice for severe mandibular retrognathism because DO could achieve more mandibular advancement and concurrent soft tissue elongation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.4
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• pp.211-220
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• 2013

Purpose: The purpose of this study was to compare the changes in the pharyngeal airway space, tongue and hyoid bone positions according to the orthognathic surgical methods of mandibular prognathism. Methods: The subjects included 30 patients (16 males, 14 females) with the skeletal class III malocclusion. Group 1 (10 patients) underwent bilateral sagittal split ramus osteotomy (BSSRO) only; group 2 (10 patients) underwent BSSRO with genioplasty; and group 3 (10 patients) underwent BSSRO, Le Fort I osteotomy. We measured the lines between the selected upper air way, hyoid bone and tongue landmarks on the lateral cephalometric x-ray films of skeletal class III. The measurements were made preoperation, within 1 week after the operation, 3~6 months after the operation and 1 year after the operation. We compared and analyzed the measurements with matched paired t-test and independent samples t-test. Results: There were no postoperative changes in the nasopharyngeal airway space in group 3. The measurements of group 3 also increased during the follow-up period as compared to the preoperative measurements. In group 1, 2 and 3, the immediate postoperative oropharyngeal and hypopharyngeal airway spaces were decreased. In the following period, the hypopharyngeal airway space returned to the preoperative positions, but the oropharyngeal airway space was not significantly changed. The upper and lower tongue was posteriorly repositioned immediately after the surgery. During the follow-up period, the lower tongue position returned to the preoperative position, and the upper tongue position was not significantly changed. Immediately after the surgery, the B point was moved to the posterior position, and a slight anterior advancement was found in the follow-up period. Conclusion: Patients who received the mandibular setback surgery showed a decrease in the posterior airway space, and those who underwent maxillary advancement showed a significant increase of the nasopharyngeal airway space, which remained stable during the evaluation period. The change of the airway space, position of the hyoid bone and tongue did not differ according to the presence or absence of genioplasty.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.5
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• pp.316-323
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• 2009

Purpose: This study was performed to evaluate three-dimensional positional change of the condyle using 3D CT after bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class III patients. Patients and methods: Nine patients who underwent BSSRO for mandibular set-back in skeletal class III malocclusion without facial asymmetry were examined. Miniplates were used for the fixation after BSSRO. 3-D CT was taken before, immediately after, and 6 months after undergoing BSSRO. After creating 3D-CT images using V-works $4.0^{TM}$ program, axial plane, coronal plane, & sagittal plane were configured. Three dimensional positional change, from each plane to the condyle, of the nine patients was measured before, immediately after, and 6 months after undergoing BSSRO. Results: 1. The mean value of mandibular set-back for nine mandibular prognathism patients was 7.36 mm (${\pm}\;2.42\;mm$). 2. In the axial view, condyle is rotated inward immediately after BSSRO (p < 0.05), comparing with preoperative but outward 6 months after BSSRO comparing with postoperative (p < 0.05). 3. In the axial view, condyle is moved laterally immediately after BSSRO (p < 0.05), comparing with preoperative but regressed 6 months after BSSRO comparing with preoperative (p > 0.05). 4. In the frontal & coronal view, there is changed immediately after and 6 months after BSSRO, comparing with preoperative but no statistical difference. Conclusion: These results indicate that three-dimensional positional change of the condyle in skeletal class III patients is observed lateral displacement & inward rotation immediate after BSSRO, but the condyle in 6 months after BSSRO tends to regress to preoperative position.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.4
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• pp.227-234
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• 2024

In patients with unilateral mandibular condyle hyperplasia, whether to perform condylectomy and orthognathic surgical procedures at the same time or orthognathic surgery in two stages for remains controversial. Reported here is a case of facial asymmetry with mandibular condyle hyperplasia, for which condylectomy and orthognathic surgery procedures were performed at the same time. A 28-year-old woman was presented to our department with chief complaints of left deviation of the mandible and right temporomandibular joint (TMJ) noise. Findings obtained in several imaging examinations led to a diagnosis of facial asymmetry associated with right mandibular condyle hyperplasia. Following 3 months of preoperative orthodontic treatment, in October 2018 under general anesthesia the patient underwent a right mandibular condylectomy, Le Fort I osteotomy, right mandibular sagittal split ramus osteotomy, and left mandibular inverted L ramus osteotomy. In examinations up to 3 years after surgery, good results were noted. For this case of severe facial asymmetry with mandibular condyle hyperplasia, early surgery and condylectomy were performed simultaneously to significantly shorten the total treatment time. The effectiveness of a surgery-early approach was confirmed by no postoperative findings indicating abnormalities in the TMJ or retroversion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.2
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• pp.184-188
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• 2001

Horner's syndrome as a complication of orthognathic surgery is given little attention of head and neck surgery and is a relatively benign and transient condition. A 18-year-old male referred to our department with long and anteriorly projected chin. The cephalometric evaluation revealed a skeletal Class III relationship. A 10-mm setback of the mandible to eliminate Class III relationship and 4-mm vertical reduction genioplasty were performed. Three weeks after operation, the patient was recognized anhidrosis in left face and the head, and ptosis of left eye. The trauma to cervical sympathetic nerve during left sagittal split ramus osteotomy was thought to be the cause of Horner's syndrome. Patient was treated by dermatologic and opthalmologic care. Follow-up examination 8 months later, he was recovery of horner's symptom.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.4
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• pp.255-268
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• 1992

There are various modalities in the treatment of facial asymmetry, but in severe case with TMD by actively growing deformed condyle, the treatment choice is removing the condyle growth center and TMD symptom such as click or muscular discomfort. In our one case, the patient was complain of facial asymmetry. There are severe deformed condyle head with bird-head fashion and enlarged mandibular ramus and body vertically about 18 mm, overgrowthed Rt. mandible body horizontally about 20 mm. She had intermittent Lt. TMJ clicking and muscular discomfort. The author diagnosed it as Lt. hemimandibular hyper-plasia & R, hemimandibular elongation, a combination form with TMD. the condyle was in active growing state in scintigraphic analysis. So we extirpated the deformed condyle by intrasoral sagittal split ramus osteotomy and reshaped the condyle and mandibular distal fragment extraorally. The distal fragment was readapted in glenoid fossa and fixated. In Rt. mandibular body area, autogenous onlay bone graft on the inferior border of mandible was performed to correct the asymmetry. The clicking and facial asymmetry was corrected and we report this results with other literature findings.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.2
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• pp.132-140
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• 2010

Purpose: The aim of this study is to identify the usefulness of unilateral mandibular angle ostectomy, so-called "Lateral Angle Reduction", in asymmetric prognathism patients by the assessment of postoperative stability and esthetic results Patients and methods: For the retrospective study, 10 skeletal class III mandibular asymmetry patients who were performed SSRO and unilateral mandibular angle ostectomy, Lateral Angle Reduction, was selected. Lateral and posterioanterior cephalogram was taken before surgery (T0), 1day after surgery (T1) and 6month after surgery (T2). To know the esthetic results the facial width and lateral facial contour were examined on posterioanterior cephalogram and to know the postoperative stability B point and Incisor inferius was examined on lateral cephalogram. Statistical analysis was performed. Results: From T0 to T1, Intergonial width was significantly decreased, dominantly at shortened side but no significant changes at lengthened side. Those were well-maintained during 6 months. Lateral facial angle and Ramus angle was significantly decreased on only shortened side from T0 to T1. As a result, after surgery, there were no significant differences in all measurements between shortened side and lengthened side. Ramus deviation angle in shortened side and ramus angle in lengthened side which reflect the angulation of ramus on frontal plane didn't show significant changes after surgery and during postsurgical periods. Lower dental midline showed no statistical changes during postsurgical period. The relapse rate on B-point was 11.92%. Conclusion: Unilateral "Lateral angle reduction" in the asymmetric mandible is valuable to obtain the narrow lower face and symmetric facial contour with a good stability.