• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.4
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• pp.169-172
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• 2014

Objectives: The purpose of this retrospective study was to compare the amount of postoperative drainage via closed suction drainage system after intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO). Materials and Methods: We planned a retrospective cohort study of 40 patients selected from a larger group who underwent orthognathic surgery from 2007 to 2013. Mean age (range) was 23.95 (16 to 35) years. Patients who underwent bilateral IVRO or SSRO were categorized into group I or group II, respectively, and each group consisted of 20 patients. Closed suction drainage system was inserted in mandibular osteotomy sites to decrease swelling and dead space, and records of drainage amount were collected. The data were compared and analyzed with independent t-test. Results: The closed suction drainage system was removed at 32 hours postoperatively, and the amount of drainage was recorded every 8 hours. In group I, the mean amount of drainage was 79.42 mL in total, with 31.20 mL, 19.90 mL, 13.90 mL, 9.47 mL, and 4.95 mL measured at 0, 8, 16, 24, and 32 hours postoperatively, respectively. In group II, the mean total amount of drainage was 90.11 mL, with 30.25 mL, 25.75 mL, 19.70 mL, 8.50 mL, and 5.91 mL measured at 0, 8, 16, 24, and 32 hours postoperatively, respectively. Total amount of drainage from group I was less than group II, but there was no statistically significant difference between the two groups (P=0.338). There was a significant difference in drainage between group I and group II only at 16 hours postoperatively (P=0.029). Conclusion: IVRO and SSRO have different osteotomy design and different extent of medullary exposure; however, our results reveal that there is no remarkable difference in postoperative drainage of blood and exudate.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.2
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• pp.184-190
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• 2000

Objective : To compare two different methods of rigid fixation in postoperative stability after mandibular setback. Material and Methods : 28 patients with Class III malocclusion were treated by bilateral sagittal split ramus osteotomy(BSSRO) and mandibular setback were selected for this study. Group A(n=14) had the bone segments fixed with monocortical miniplate on the lateral side of the mandibular body and Group B(n=14) had three noncompressive bicortical screw inserted at the genial area through a transcutaneous approach. Cephalograms were taken preoperatively, postoperatively within 1 weeks and at a follow-up period (mean 8.9 months after surgery) and the amount of setback and postoperative change were measured. Results : Postoperative relapse between two groups was minimal in setback of the mandible. Statistical analysis showed no significant difference in postoperative relapse. Conclusion : This study suggests that both methods of skeletal fixation investigated give comparable postoperative stability and their use in mandibular setback appears to be a fairly stable clinical procedure .

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.129-137
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• 2006

The treatment plan for orthognathic surgery must be based on accurate predictions, and this can be produced the most esthetic, functional and stable results. The purpose of this study was aimed to evaluate the amount and interrelationship of the gonial angle and the mandibular width change after the mandibular setback surgery in the mandibular prognathic patients. Twenty patients were selected who received orthognathic surgery after presurgical orthodontic treatment. The patients with skeletal and dental Class III malocclusion were operated upon with bilateral sagittal split ramus osteotomy and mandibular setback. The lateral and posteroanterior cephalometric radiographs were taken preoperatively, postoperative 1 day and 12 months later after the orthognathic surgery, and then the gonial angle and mandibular width were measured. The computerized statistical analysis was carried out with SPSS/PC program. The gonial angle at postoperative 1 day was decreased about $5.3^{\circ}$ than preoperative value and the gonial angle at postoperative 12 months was increased about $1.4^{\circ}$ than postoperative 1 day. So the gonial angle at postoperative 12 months was decreased about $3.9^{\circ}$ than preoperative value. The mean preoperative gonial angle was $125.35^{\circ}{\pm}7.36$, showing significantly high value than normal and mean gonial angle at postoperative 12 months was $121.45^{\circ}{\pm}6.81$, showing value near to normal. The mandibular width at postoperative 1 day was decreased about 1.1 mm than preoperative value and the mandibular width at postoperative 12 months was more decreased about 1.7 mm than postoperative 1 day. So the mandibular width at postoperative 12 months was decreased about 2.8 mm than preoperative value. These results indicate that sagittal split ramus osteotomy in mandibular prognathic patients with high gonial angle is effective to improvement of gonial angle. It is considered to be helpful for maintenance of postoperative stable gonial angle area that detailed postoperative care and follow-up.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.41.1-41.11
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• 2020

Background: Orthognathic surgery such as bilateral sagittal split ramus osteotomy (BSSRO) for the treatment of mandibular deformities is one of the most common procedures in maxillofacial operations that may lead to neurosensory disturbance. In this study, we aimed to evaluate the effectiveness of low-level laser therapy (LLLT) on augmenting recovery of neurosensory disturbance of inferior alveolar nerve (IAN) in patients who underwent BSSRO surgery. Methods: A comprehensive literature search was conducted by two independent authors in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, Embase, and Google Scholar electronic databases. Besides, a manual search of all textbooks and relevant articles were conducted. Searches took place in August 2020 and were limited to published and peer-reviewed articles from 2000 to 2020. All analysis was performed using the comprehensive meta-analysis (CMA) and the STATA MP (version:16) software. The weighted mean difference (WMD) using the inverse variance method and the standard mean difference (SMD) was considered for continuous variables. Results: Seventy-four papers were retrieved after removing duplicate studies and finally, eight studies were assessed for qualitative synthesis and five for meta-analysis. Totally, 94 patients were included in the meta-analysis. Based on the meta-analysis, it was shown that LLLT was not effective in a short interval (0 to 48 h) after surgery, but in a period of more than 1 month after surgery, the positive results of treatment can be observed strikingly. Also, LLLT side/group showed no significant difference in some aspects of neurosensory recovery such as thermal sensation compared to the placebo side/group. Conclusions: The meta-analysis of randomized controlled trials revealed that LLLT generally improves IAN sensory disturbance caused by BSSRO. Further high-quality clinical trials with longer follow-up periods and larger sample sizes are recommended.

• 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.

• The korean journal of orthodontics
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• v.54 no.4
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• pp.247-256
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• 2024

Objective: This retrospective study evaluated the mandibular condyle position before and after bimaxillary orthognathic surgery performed with the mandibular condyle positioned manually in patients with mandibular prognathism using cone-beam computed tomography. Methods: Overall, 88 mandibular condyles from 44 adult patients (20 female and 24 male) diagnosed with mandibular prognathism due to skeletal Class III malocclusion who underwent bilateral sagittal split ramus osteotomy (BSSRO) and Le Fort I performed using the manual condyle positioning method were included. Cone-beam computed tomography images obtained 1-2 weeks before (T0) and approximately 6 months after (T1) surgery were analyzed in three planes using 3D Slicer software. Statistical significance was set at P < 0.05 level. Results: Significant inward rotation of the left mandibular condyle and significant outward rotation of the right mandibular condyle were observed in the axial and coronal planes (P < 0.05). The positions of the right and left condyles in the sagittal plane and the distance between the most medial points of the condyles in the coronal plane did not differ significantly (P > 0.05). Conclusions: While the change in the sagittal plane can be maintained as before surgery with manual positioning during the BSSRO procedure, significant inward and outward rotation was observed in the axial and coronal planes, respectively, even in the absence of concomitant temporomandibular joint disorder before or after the operation. Further long-term studies are needed to correlate these findings with possible clinical consequences.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.1
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• pp.1-6
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• 2002

When bilateral sagittal split ramus osteotomy or mandibular angle reduction are carried out, we have to consider the position of inferior alveolar nerve. For bone splitting or resection using a saw or an osteotome, the bucco-lingual position of the inferior alveolar nerve plays an important role in the preventing perioperative complications such as paresthesia or anesthesia. Because it is rare to find literatures concerning the mean anatomic position of the inferior alveolar nerve in Koreans, we investigated 30 patients who underwent to take CT and orthopantomogram for implant surgery, and evaluated the bucco-lingual position and vertical relationship of the inferior alveolar nerve at the mandible. The results showed that the distance between inferior alveolar nerve and buccal plate was the farthest at mandibular second molar ($7.1{\sim}7.4mm$) and the nearest at mandibular angle area ($4.4{\sim}4.8mm$). But it was no statistical relationship between the bucco-lingual postion of inferior alveolar nerve on the CT and its vertical position on the OPT. In conclusion, the results suggest that a careful surgical procedure is needed at the mandibular angle area to avoid a nerve damage and there are sufficient bone materials at the mandibular second molar are for bilateral sagittal split ramus osteotomy or mandibular angle reduction or plate fixation. And OPT is not usefull for the evaluation of a relative bucco-lingual position of inferior alveolar nerve in relation to its vertical postion on the OPT.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.3
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• pp.196-204
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• 2002

For the study of its stability when the screw has been fixed after sagittal split ramus osteotomy(SSRO) of the mandible, the methods of screw arrangement are classified into two types, triangular and straight. The angles of screws to the bone surface are classified as perpendicular arrangements, the $60^{\circ}$ anterioinferior screw, known as triangular, and the most posterior screw, called straight arrangement, thus there are four types. The finite element method model has been made by using a three dimensional calculator and a supercomputer. The load directions are to the anterior teeth, premolar region, and molar region, and the bite force is 1 Kgf to each region. The distribution of stress, the von-Mises yield strength, and safety of margin refer to the total sum of transformed energy have been studied by comparison with each other. The following conclusion has been researched : 1. When shear stress is compared, in the triangular arrangement in the form of "ㄱ", the anterosuperior screw is seen at contributing to the support of the bone fragment. In the straight arrangement, substantial stress is seen to be concentrated on the most posterior angled screw. 2. When the von-Mises yield strength is compared, it seemed that the stress concentration on the angled anteroinferior screw is higher, it shows a higher possibility of fracture than any other screw. In the straight arrangement, stress appeared to be concentrated on the most posteriorly angled screw. 3. When the safety margins of the transfomed energy are compared, the energy conduction is much greater in the case of the angled screw than in the case of the perpendicular screw. The triangular arrangement in the form of "ㄱ" shows a superior clinical sign to that of the straight arrangement. Judging from the above results, when the screw fixation is made after SSRO in practical clinical cases, two screws should be inserted in the superior border of mandibular ramus and a third screw of mandibular inferior border should be inserted in the form of triangular. All screws on the bony surface should be placed perpendicularly-$90^{\circ}$ angles apparently best promote bony support and stability.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.36.1-36.5
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• 2018

Background: Botulinum toxin-A (BTX-A) injection into muscle reduces muscular power and may prevent post-operative complication after orthognathic surgery. The purpose of this study was (1) to evaluate BTX-A injection into the masseter muscle on the prevention of plate fracture and (2) to compare post-operative relapse between the BTX-A injection group and the no injection group. Methods: Sixteen patients were included in this study. Eight patients received BTX-A injection bilaterally, and eight patients served as control. All patients received bilateral sagittal split ramus osteotomy for the mandibular setback and additional surgery, such as LeFort I osteotomy or genioplasty. Post-operative plate fracture was recorded. SNB angle, mandibular plane angle, and gonial angle were used for post-operative relapse. Results: Total number of fractured plates in patients was 2 out of 16 plates in the BTX-A injection group and that was 8 out of 16 plates in the no treatment group (P = 0.031). However, there were no significant differences in post-operative changes in SNB angle, mandibular plane angle, and gonial angle between groups (P > 0.05). Conclusions: BTX-A injection into the masseter muscle could reduce the incidence of plate fracture.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.5
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• pp.329-334
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• 2009

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.