• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.2
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• pp.102-108
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• 2015

In surgery for facial asymmetry, mandibles can be classified into two types, rotational and translational, according to the required mandibular movements for surgery. During surgery for rotational mandibular asymmetry, a bilateral sagittal split ramus osteotomy (BSSRO) may cause a large bone gap between the proximal and distal segments as well as condylar displacement, resulting in a relapse of the temporomandibular joint disorder, especially in severe cases. The intraoral vertical ramus osteotomy has an advantage, in this respect, because it causes less rotational displacement of the proximal segment on the deviated side and even displaced or rotated condylar segments may return to their original physiologic position. Unilateral intraoral vertical ramus osteotomy (UIVRO) on the short side combined with contralateral SSRO was devised as an alternative technique to resolve the spatial problems caused by conventional SSRO in cases of severe rotational asymmetry. A series of three cases were treated with the previously suggested protocol and the follow-up period was analyzed. In serial cases, UIVRO combined with contralateral SSRO may avoid mediolateral flaring of the bone segments and condylar dislocation, and result in improved condition of the temporomandibular joint. UIVRO combined with contralateral SSRO is expected to be a useful technique for the treatment of rotational mandibular asymmetry.

• 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.37 no.6
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• pp.539-544
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• 2011

Maxillary canting and vertical shortening of the unilateral mandibular ramus height is common in cases of severe facial asymmetry. Normally, mandibular distraction osteogenesis (DO) with horizontal osteotomy at the ascending ramus is used for vertical lengthening of the mandibular ramus to correct facial asymmetry with an absolute shortened ascending ramus. In this case report, vertical lengthening of the ascending ramus was performed successfully with unilateral DO and sagittal split ramus osteotomy (SSRO), where the posterior part of the distal segment can be distracted simultaneously in an inferior direction with maxillary DO, resulting in a lengthening of the medial pterygoid muscle. This case describes the acquired unilateral mandibular hypoplasia caused by a condylar fracture at an early age, which resulted in abnormal mandibular development that ultimately caused severe facial trismus. The treatment of this case included two-stage surgery consisting of bimaxillary distraction osteogenesis for gradual lengthening of the unilateral facial height followed by secondary orthognathic surgery to correct the transverse asymmetry. At the one year follow-up after SSRO, the vertical length was maintained without complications.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.4
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• pp.208-212
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• 2015

Keratocystic odontogenic tumor (KCOT) is a common benign tumor of osseous lesions in dental and maxillofacial practice. We describe three cases of large KCOT located in the posterior part of the mandible extending to the angle and ramus region, which were enucleated via sagittal split osteotomy (SSO) of the mandible. There are cases in which a conventional enucleation procedure does not ensure complete excision of the entire lesion without damage to vital structures like the inferior alveolar nerve. In such cases, a SSO approach could be a better choice than conventional methods. The purpose of this article is to describe our experience using unilateral mandibular SSO for removal of a KCOT from the mandible.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.373-381
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• 2021

Objectives: In the present study, the effects of sagittal split ramus osteotomy (SSRO) combined with intraoral vertical ramus osteotomy (IVRO) for the treatment of asymmetric mandible in class III malocclusion patients were assessed and the postoperative stability of the mandibular condyle and the symptoms of temporomandibular joint disorder (TMD) evaluated. Materials and Methods: A total of 82 patients who underwent orthognathic surgery for the treatment of facial asymmetry or mandibular asymmetry at the Department of Oral and Maxillofacial Surgery, Dong-A University Hospital, from 2016 to 2021 were selected. The patients that underwent SSRO with IVRO were assigned to Group I (n=8) and patients that received bilateral SSRO (BSSRO) to Group II (n=10, simple random sampling). Preoperative and postoperative three-dimensional computed tomography (CT) axial images obtained for each group were superimposed. The condylar position changes and degree of rotation on the superimposed images were measured, and the changes in condyle based on the amount of chin movement for each surgical method were statistically analyzed. Results: Group I showed a greater amount of postoperative chin movement. For the amount of mediolateral condylar displacement on the deviated side, Groups I and II showed an average lateral displacement of 0.07 mm and 1.62 mm, respectively, and statistically significantly correlated with the amount of chin movement (P=0.004). Most of the TMD symptoms in Group I patients who underwent SSRO with IVRO showed improvement. Conclusion: When a large amount of mandibular rotation is required to match the menton to the midline of the face, IVRO on the deviated side is considered a technique to prevent condylar torque. In the present study, worsening of TMD symptoms did not occur after orthognathic surgery in any of the 18 patients.

• The korean journal of orthodontics
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• v.49 no.1
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• pp.59-69
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• 2019

In this report, we describe a case involving a 34-year-old woman who showed good treatment outcomes with long-term stability after multidisciplinary treatment for unilateral cleft lip and palate (CLP), maxillary hypoplasia, severe maxillary arch constriction, severe occlusal collapse, and gingival recession. A comprehensive treatment approach was developed with maximum consideration of strong scar constriction and gingival recession; it included minimum maxillary arch expansion, maxillary advancement by distraction osteogenesis using an internal distraction device, and mandibular setback using sagittal split ramus osteotomy. Her post-treatment records demonstrated a balanced facial profile and occlusion with improved facial symmetry. The patient's profile was dramatically improved, with reduced upper lip retrusion and lower lip protrusion as a result of the maxillary advancement and mandibular setback, respectively. Although gingival recession showed a slight increase, tooth mobility was within the normal physiological range. No tooth hyperesthesia was observed after treatment. There was negligible osseous relapse, and the occlusion remained stable after 5 years of post-treatment retention. Our findings suggest that such multidisciplinary approaches for the treatment of CLP with gingival recession and occlusal collapse help in improving occlusion and facial esthetics without the need for prostheses such as dental implants or bridges; in addition, the results show long-term post-treatment stability.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.4
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• pp.407-413
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• 2000

To evaluate the stability after orthognathic surgery in cleft lip and palate patients using rigid fixation, 20 patients underwent primary repair in childhood and later developed a jaw deformity and malocclusion that required orthognathic surgery were reviewed. Two groups, one of 10 patients performed Le Fort I osteotomy with sagittal split ramus osteotomy and one of 10 patients with sagittal split ramus osteotomy of the mandible, were evaluated. Each group had unilateral cleft only and all alveolar cleft sites had been grafted with autogeneous bone before the orthognathic surgery. The amount of surgical movement and relapse were compared in both horizontal and vertical dimensions. Two-jaw surgery group was more stable than mandibular surgery only group in mandibular position (p< 0.05). Statistically significant relapse was observed in mandibular skeletal point in mandibular surgery group (p<0.05). There was no statistically significant relapse in the skeletal point of two-jaw surgery group. However, the correlation between the horizontal surgical movement and relapse was detected (r = 0.88). This correlation indicates the need of overcorrection. The presence of scar tissues and relatively deficient maxillary bone could be attributed to this close relation between the surgical change and relapse.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.36.1-36.7
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• 2015

Background: This study was performed to evaluate three-dimensional positional change of the condyle using three-dimensional computed tomography (3D-CT) following unilateral sagittal split ramus osteotomy (USSRO) in patients with mandibular prognathism. Methods: This study examined two patients exhibiting skeletal class III malocclusion with facial asymmetry who underwent USSRO for a mandibular setback. 3D-CT was performed before surgery, immediately after surgery, and 6 months postoperatively. After creating 3D-CT images by using the In-vivo $5^{TM}$ program, the axial plane, coronal plane, and sagittal plane were configured. Three-dimensional positional changes from each plane to the condyle, axial condylar head axis angle (AHA), axial condylar head position (AHP), frontal condylar head axis angle (FHA), frontal condylar head position (FHP), sagittal condylar head axis angle (SHA), and sagittal condylar head position (SHP) of the two patients were measured before surgery, immediately after surgery, and 6 months postoperatively. Results: In the first patient, medial rotation of the operated condyle in AHA and anterior rotation in SHA were observed. There were no significant changes after surgery in AHP, FHP, and SHP after surgery. In the second patient, medial rotation of the operated condyle in AHA and lateral rotation of the operated condyle in FHA were observed. There were no significant changes in AHP, FHP, and SHP postoperatively. This indicates that in USSRO, postoperative movement of the condylar head is insignificant; however, medial rotation of the condylar head is possible. Although three-dimensional changes were observed, these were not clinically significant. Conclusions: The results of this study suggest that although three-dimensional changes in condylar head position are observed in patients post SSRO, there are no significant changes that would clinically affect the patient.

• 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.

• The korean journal of orthodontics
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• v.50 no.5
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• pp.336-345
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• 2020

Objective: To investigate the treatment modalities (Tx-Mods) for patients with unilateral hemifacial microsomia (UHFM) according to Pruzansky-Kaban types and growth stages. Methods: The samples consisted of 82 Korean UHFM patients. Tx-Mods were defined as follows: Tx-Mod-1, growth observation due to mild facial asymmetry; Tx-Mod-2, unilateral functional appliance; Tx-Mod-3, fixed orthodontic treatment; Tx-Mod-4, growth observation due to a definite need for surgical intervention; Tx-Mod-5, unilateral mandibular or bimaxillary distraction osteogenesis (DO); Tx-Mod-6, maxillary fixation using LeFort I osteotomy and mandibular DO/sagittal split ramus osteotomy; Tx-Mod-7, orthognathic surgery; and Tx-Mod-8, costochondral grafting. The type and frequency of Tx-Mod, the number of patients who underwent surgical procedures, and the number of surgeries that each patient underwent, were investigated. Results: The degree of invasiveness and complexity of Tx-Mod increased, with an increase in treatment stage and Pruzansky-Kaban type (initial < final; [I, IIa] < [IIb, III], all p < 0.001). The percentage of patients who underwent surgical procedures increased up to 4.2 times, with an increase in the Pruzansky-Kaban type (I, 24.1%; IIa, 47.1%; IIb, 84.4%; III, 100%; p < 0.001). However, the mean number of surgical procedures that each patient underwent showed a tendency of increase according to the Pruzansky-Kaban types (I, n = 1.1; IIa, n = 1.5; IIb, n = 1.6; III, n = 2.3; p > 0.05). Conclusions: These findings might be used as basic guidelines for successful treatment planning and prognosis prediction in UHFM patients.