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

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.33 no.3
• /
• pp.276-280
• /
• 2011

BSSRO (bilateral sagittal split ramus osteotomy) is an effective surgical method for maxillofacial deformities. Rigid fixation using a plate and screws can stabilize bony segments and induce early mouth opening. Though this procedure has a low complication rate, normal function and esthetic recovery is achieved through proper and early management of the complications. Complications consisting of temporomandibular disorders, sensory disturbances due to inferior alveolar nerve damage, open bite, malunion or nonunion, and facial nerve palsy occur, but these rarely develop. Facial nerve palsy causes the muscles involved in facial expression to depress, which results in ocular dryness or retinal damage. When facial nerve palsy develops, early management involving steroid medication and physical therapy is effective. In the case of severe damage, surgical intervention should be considered. A 20-year-male patient came to the oral and maxillofacial surgery department for orthognathic surgery. The mandible was set back by BSSRO under general anesthesia. Facial nerve palsy was observed on the left side of the face: steroid and vitamins were administered early and physical therapy was performed daily. These forms of management can aid in function and allow for gradual esthetic recovery. Presumed causes were excessive soft tissue retraction or soft tissue injury by the osteotome at the horizontal osteotomy of the ramus. Careful dissection, retraction and a precise osteotomy are needed for protection of the facial nerve. If nerve damage is observed, early management can help in the recovery of facial nerve function and esthetics.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.32 no.2
• /
• pp.141-148
• /
• 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
• /
• v.35 no.4
• /
• pp.211-220
• /
• 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.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.22 no.1
• /
• pp.51-55
• /
• 2000

Purpose : The purpose of this study is to setup a standard treatment protocol in surgical correction of skeletal malocclusion with Angle Class III patients. We asessed the soft tissue changes according to skeletal changes of patients who have undergone orthognathic surgery with bilateral split sagittal ramus osteotomy (BSSRO) and advancing genioplasty. Materials & Methods : The soft tissue change of 9 skeletal Class III patients was assessed after BSSRO and advancing genioplasty. The patient group was skeletal Class III who was surgically treated by BSSRO & advancing genioplasty. The average follow up period is 13 months with the range of 6 and 30 months. All patients have undergone preoperative and postoperative orthodontic treatment. The assessment was devided into two groups. One was antero-posterior relationship and the other was vertical relationship of dimensional changes of soft tissue after orthognathic surgery. Results : In antero-posterior dimensional changes after surgery, the percentage of soft tissue change in comparison to hard tissue was 89%. Vertical ratio after surgery, 86% soft tissue changes were assessed.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.38
• /
• pp.25.1-25.4
• /
• 2016

Background: Bilateral sagittal split ramus osteotomy (BSSRO) is the most widely used mandibular surgical technique in orthognathic surgery and is easy to relocate the distal segments, accelerating bone repair by the large surface of bone contact. However, it can cause neurosensory dysfunction (NSD) or sensory loss by injury of the inferior alveolar nerve. The purpose of the present study was to evaluate NSD after BSSRO and modifiers at NSD recovery. Methods: In this study, NSD characteristics after BSSRO from 2009 to 2014 at the Kyung Hee University Dental Hospital were evaluated. The pattern of sensory recovery over time was also evaluated based on factors such as field of sensory dysfunction, surgical procedure, presence of pre-operative facial asymmetry, and postoperative medications. Results: Most of the patients had shown NSD immediately after orthognathic surgery. Among the 1192 sides of 596 patients, NSD was observed in 953 sides and 544 patients. Sexual predilection was shown in males (p value = 0.0062). In the asymmetric group of 132 patients, NSD was observed in 128 patients (96.97 %). In the symmetric group of 464 patients, NSD was observed in 416 patients (89.45 %); on the other hand, NSD was observed significantly higher in the asymmetric group (p = 0.025). NSD-associated factors were analyzed, and vitamin B12 may be beneficial for NSD recovery. Conclusions: There was a difference between the symmetric group and the asymmetric group in NSD recovery. Vitamin B12 can be regarded as an effective method to nerve recovery. However, a further prospective study is needed.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.23 no.2
• /
• pp.144-154
• /
• 2001

Dysfunction of the inferior alveolar nerve indicated by various degree of numbness of the lower lip and chin is one of the few drawbacks of mandibular osteotomy, especially Bilateral Sagittal Split Ramus Osteotomy(BSSRO) and genioplasty. Although it has been recorded throughout the history of this techniques, it is true etiology poorly understood. In this study, 22 consecutive patients under class III malocclusiion impression and undergoing orthognathic surgery(BSSRO only 11 case, BSSRO with genioplasty 11 case) were studied using 4 neurosensory test(static light touch, directional discrimination, two-point discrimination, pin pressure nociception) with post OP 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 24 weeks, On control group, 10 members without trauma and nerve damage history, nerve test was accomplished. We concluded majority of patients return of sensation during post operative 24 weeks. Althought immediate nerve deficit are 92.2%, 97.2% 88.9% these are recovered to 25%, 35.72%, 10.71% at 24 weeks. Nerve recovery rate increased prominently between post 4 weeks and 8 weeks. There is no statistically difference about neurosensory deficit among the chin area. Neurosensory deficit more severe when the BSSRO with genioplasty group than the only BSSRO group. Immediate neurosensory deficit is larger left side than right side but after 6 months, there is no significantly difference between left side and right side. Static light touch and pin pressure nociception are more sensitive method of neurosensory deficit than two point discrimination.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.31 no.6
• /
• pp.485-491
• /
• 2009

Postoperative skeletal stability was evaluated in combination of Le Fort I and U-shaped osteotomies for superior repositioning of maxilla in bi-maxillary surgeries in 30 consecutive patients. The fifteen patients underwent Le Fort I osteotomy alone and the other fifteen patients underwent Le Fort I and U-shaped osteotomies. In all patients, the maxilla was first osteomized and fixed with absorbable plates system. A bilateral sagittal split ramus osteotomy (BSSRO) of the mandible was then carried out and fixation was performed using absorbable plates. Maxillo-mandibular fixation with rubber ring was used for two weeks post-operatively in all patients. Lateral cephalograms were obtained pre-operatively, 1 day post-operatively, 6 months after surgery. The changes in anterior nasal spine (ANS), point A, upper incisior (U1), and point of maxillary tuberosity (PMT) were examined. The maxillas in the fifteen patients of both examination group were repositioned nearly in their planned positions during surgery and no significant post-operative changes in the examined points of the maxilla were found. These results suggest that a combination of a Le Fort I and U-shaped osteotomy is a useful technique for reliable superior repositioning of the maxilla. The post-operative change in the maxilla using this combination osteotomy was comparatively stable.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.31 no.1
• /
• pp.55-59
• /
• 2005

Purpose : This study is to predict the changes of the distal segment by investing the resorption of the excessive distal segment regarding the amount of setback after BSSRO. Material and Methods : 20 patients with Mandible prognathism treated by Obwegeser-Dal Pont method during the years 2000 to 2002 were selected for this study. Group A consisted of 5 males & 5 females with a setback amount of 10mm and above(Mean $10.80mm{\pm}1.03$, n=20) and Group B consisted of 2 males & 8 females with a setback amount of below 10mm.(Mean $6.10mm{\pm}1.10$, n=20) Panorama X-ray was taken at day 1, 1month, 3months, 6months, and 12months after the surgery. Resorption areas of excessive distal segment were measured on these panorama X-rays and compared. Results : There was bone resorption in both groups. Group A showed more bone resorption than Group B. Group B showed slightly higher resorption rate than Group A. However, there was no statistically significant difference between the resorption rates of Group A and Group B. (P>0.05). Conclusion : More bone resorption occurred with a larger amount of setback and about one third of the excessive distal segment underwent resorption, irrespective of the amount of setback.

• The Journal of Advanced Prosthodontics
• /
• v.3 no.1
• /
• pp.51-55
• /
• 2011

BACKGROUND. Mandibular displacement is a common complication of condylar fracture. In the mandibular displacement due to condylar fracture, it is difficult to restore both esthetics and function without using orthognathic surgery. CASE DESCRIPTION. This clinical report described a full mouth rehabilitation in the patient with bilateral condylar fractures and displaced mandible using bilateral sagittal split ramus osteotomy (BSSRO) and simultaneous dental implant surgery. Mandibular position was determined by model surgery through the diagnostic wax up and restoration of fractured teeth. The precise amount of the mandibular shift can be obtained from the ideal intercuspation of remaining teeth. CLINICAL IMPLICATION. Mandibular displacement by both condylar fractures can be successfully treated by orthognathic surgery. Determination of occlusal plane and visualization from diagnostic wax up are mandatory for mandibular repositioning of model surgery. Stable occlusion and regular recall check up are needed for long-term outcome.