Intraoral vertical ramus osteotomy for correction of mandibular prognathism: long-term stability

Various techniques and modifications have been introduced in the treatment of mandibular prognathism. However, there are still few reports concerning long-term stability, especially using the intraoral vertical ramus osteotomy (IVRO) method. The purpose of this study was to investigate the long-term stability for correction of mandibular prognathism using IVRO. Twenty-five mandibular prognathism patients were treated by bilateral IVRO, and were evaluated cephalometrically by reference to the menton. A set of 3 standardized lateral cephalograms were obtained from each subject preoperatively (T1), immediately postoperatively (T2), and after 2 years postoperatively (T3). Relapse was defined as forward movement of menton after the 2-year follow-up. The mean setback of the menton was 12.8 mm in horizontal direction and 0.9 mm downward in vertical direction. The average follow-up was 33.9 months. The mean relapse was 1.3 mm (10.2% = 1.3 of 12.8) in forward direction and 0.6 mm in upward direction. There was no significant movement in the vertical direction. However, significant relapse was shown in the horizontal direction, even though the amount was small. The long-term stability of our present study suggested that IVRO is useful for correction of mandibular prognathism.     

Changes in the temporomandibular joint after mandibular setback surgery in monkeys: intraoral vertical versus sagittal split ramus osteotomy.

OBJECTIVE: This study was to investigate the changes in condylar position and structure of the temporomandibular joint (TMJ) after mandibular setback using 2 forms of the ramus osteotomy. STUDY DESIGN: Twelve adult male rhesus monkeys were randomly divided into groups A (n = 6) and B (n = 6) for mandibular setback surgical procedure. An intraoral vertical ramus osteotomy (IVRO) was performed in group A, whereas a sagittal split ramus osteotomy (SSRO) was performed in group B. Changes in condylar position were quantified by computed tomography (CT) preoperatively and postoperatively. All animals in groups A and B were killed at 12 weeks after surgical procedure. The TMJ specimens were harvested and processed for histological examination. RESULTS: In group A, the CT examinations showed a significant anteroinferior displacement of the condyle after surgical procedure. In group B, slight posterior displacement and lateral tilting of the condyle were noted after surgical procedure. Thickened cartilage layer and endochondral ossification were seen in the condyles of group A, but only minimal alteration in articular cartilage was found in group B. CONCLUSIONS: Both SSRO and IVRO can be biologically sound procedures for correction of mandibular prognathism. Intraoral vertical ramus osteotomy procedure leads to condylar adaptive remodeling, which may have favorable effects on TMJ, and it could be considered as a preferred surgical treatment for those patients with preoperative TMJ disorders.     

Evaluation of upper lip hypoesthesia with a trigeminal somatosensory-evoked potential following Le Fort I osteotomy in combination with mandibular osteotomy.

PURPOSE: The purpose of this study was to objectively evaluate hypoesthesia of the upper lip following Le Fort I osteotomy in combination with mandibular osteotomy with trigeminal somatosensory evoked potential (TSEP). SUBJECTS AND METHODS: The subjects consisted of 25 patients with mandibular prognathism with maxillary retrognathism mandibular prognathism with or without asymmetry, who underwent Le Fort I osteotomy in combination with sagittal split ramus osteotomy (SSRO) or intraoral vertical ramus osteotomy (IVRO).Trigeminal nerve hypoesthesia at the region of the upper lip was assessed bilaterally by the TSEP method. The electrodes were placed exactly above the highest point of the vermilion border and on the mucosa of the upper lip. An electroencephalograph recording system (Neuropack Sigma; Nihon Koden Corp., Tokyo, Japan) was used to analyze the potentials. Each patient was evaluated preoperatively and then postoperatively at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 1 year. RESULTS: The average measurable period and standard deviation of TSEP of the upper lip was 7.8 +/- 10.7 weeks following Le Fort I osteotomy, TSEP of the lower lip was 4.6 +/- 9.2 weeks in the patients who underwent SSRO with Le Fort I osteotomy, and 1.2 +/- 0.4 weeks in the patients who underwent IVRO with Le Fort I osteotomy. CONCLUSION: This study objectively proved that hypoesthesia could appear in the upper lips following Le Fort I osteotomy with TSEP. The measurable period for the upper lip following Le Fort I osteotomy tended to be longer than that for the lower lip in the patients who underwent SSRO and IVRO with Le Fort I osteotomy.     

Skeletal changes after modified intraoral vertical ramus osteotomy for correction of mandibular prognathism.

BACKGROUND: Orthognathic surgery is widely used to correct congenital and acquired dentofacial discrepancies. Various surgical procedures have been advocated for correction of mandibular prognathism. In this study, a modified intraoral vertical ramus osteotomy has been developed for surgical correction of mandibular prognathism. The aim of this study is to identify contributing factors to skeletal change by analysing cephalometric changes after modified intraoral vertical ramus osteotomy. METHODS: Forty-one patients, treated for absolute mandibular prognathism by bilateral modified intraoral vertical ramus osteotomy, were evaluated cephalometrically with reference to the menton point. A set of four standardised lateral cephalograms were obtained from each subject preoperatively (T1) and immediately postoperatively (T2), prior to removal of maxillomandibular fixation (T3), and at 1-year postoperatively (T4). The mean setback of the menton was 12.4 mm in the horizontal direction. Relapse was defined as forward movement of the menton during the 1-year follow-up. RESULTS: The highly significant backward movements in a horizontal direction were observed during the maxillomandibular fixation period (T3-T2). Moreover, highly significant forward movement was observed following the maxillomandibular fixation period (T4-T3). After 1-year follow-up (T4-T2), the mean changes of the menton were 0.1 mm backward in the horizontal direction. CONCLUSIONS: In this series, the mean skeletal change compared with the amount of setback was less than 1% (0.1/12.4 mm) in backward movement. The results suggest that the modified intraoral vertical ramus osteotomy technique is useful and the more stable approach for correction of severe mandibular prognathism.     

The Stability of Intraoral Vertical Ramus Osteotomy and Factors Related to Skeletal Relapse

Background  

Intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO) have been advocated as two major procedures for the correction of mandibular prognathism. However, only a few reports with at least a 2-year follow-up period describe the long-term stability especially of the IVRO method. This study aimed to identify factors contributing to skeletal relapse after a 2-year postoperative follow-up period.     

Condylar luxation following bilateral intraoral vertical ramus osteotomy.

OBJECTIVE: The intraoral vertical ramus osteotomy (IVRO) is widely used to treat mandibular prognathism and some forms of temporomandibular joint disorder (TMD). This retrospective report evaluated the incidence of condylar luxation following bilateral IVRO. STUDY DESIGN: Clinical records and radiographs of 319 patients seen during a 13-year period between 1992 and 2005 were evaluated. The mean age of the patients (232 females, 87 males) at the time of surgical procedure was 26.1 years. All patients underwent a bilateral IVRO to treat mandibular prognathism or TMD. Postoperatively, the condylar position was evaluated from lateral and anteroposterior cephalograms and tomograms of the temporomandibular joint (TMJ). RESULTS: An IVRO was performed on 638 sides in 319 patients. In 8 sides in 8 patients, the proximal segments were dislocated, and the condylar heads were located beyond the articular eminence. One patient underwent a closed reduction under local anesthesia, and 4 patients underwent an open reduction under sedation or general anesthesia. The average follow-up period was 4.3 years (1.2-9 years). Six of the 8 patients did not complain of any TMJ dysfunction. The objective clinical evaluation also did not reveal any dysfunctional patterns. A TMJ click on the affected side was observed in 1 patient, and mandibular deviation to the affected side upon opening the mouth was observed in 1 patient. CONCLUSION: Although condylar sag is a consistent finding after IVRO, the mandibular condyles tend to return their preoperative positions. In this study, condylar luxation was observed in 1.3% (8/638) of the joints after bilateral IVRO. However, there were no severe clinical problems in these patients during a relatively long follow-up period.     

Evaluation of intraoral verticosagittal ramus osteotomy for correction of mandibular prognathism: a 10-year study.

PURPOSE: To identify intraoperative complications, neurosensory disturbance (NSD), and horizontal relapse after surgical correction of mandibular prognathism using bilateral intraoral verticosagittal ramus osteotomy (IVSRO). PATIENTS AND METHODS: Between 1995 and 2005, 237 Iranian patients underwent IVSRO to achieve mandibular setback. Their operation reports, cephalometric radiographs (2 weeks preoperatively and 12 months postoperatively), and neurosensory questionnaires were assessed to identify intraoperative complications, NSD of the inferior alveolar nerve (IAN), and horizontal relapse. RESULTS: Intraoperative complications occurred in 26 cases (11%). A total of 17 patients (7.2%) reported NSD of the IAN. The mean surgical setback was 7.99 mm at the B point, and the mean horizontal relapse was 2.16 mm at the B point (after 1 year). CONCLUSIONS: Considering our findings, the benefits of the IVSRO technique (eg, good contact between the 2 parts of the osteotomy, capacity for rigid fixation, low incidence of IAN injury) demonstrate that this technique can easily replace the intraoral vertical ramus osteotomy technique to treat mandibular prognathism and is a viable alternative to the sagittal split osteotomy technique to provide mandibular setback.     

Condylar head remodeling following mandibular setback osteotomy for prognathism: a comparative study of different imaging modalities.

PURPOSE: Condylar remodeling, which develops after mandibular setback osteotomy, was evaluated and compared in CT, plain film radiographs, and MR images acquired postoperatively. METHODS: Thirty-nine patients treated with sagittal split ramus osteotomy (SSRO) and 46 patients treated with intraoral vertical ramus osteotomy (IVRO) were studied. Remodeling as seen in the images and the diagnostic agreement between imaging modalities was evaluated. RESULTS: A newly formed bone layer in the posterior part of the condylar head was identified as a sign suggestive of remodeling. This sign was seen predominantly at periods over 6 months postoperatively. IVRO subjects had a higher incidence of remodeling than did the SSRO group. The diagnostic agreement between the 3 imaging modalities was substantial. There was a positive correlation between postoperative condylar displacement and the incidence of remodeling. CONCLUSIONS: The incidence of postoperative condylar head remodeling may be predictable. High-dose postoperative imaging studies to assess the TMJ should be restricted to those cases having a clear need for such studies.     

Mandibular symphyseal contouring in mild mandibular prognathism

K?lle's mandibular segmental osteotomy, with extraction of the bilateral first bicuspids, is often used in cases of mild mandibular prognathism. While mandibular prognathism is usually corrected by mandibular ramus osteotomy and the mandible is set back en bloc, the premolar region alone is set back by segmental osteotomy, retaining the protruding mental area. In Asians, particularly, the protruding chin is not preferred by our concepts of beauty. In mandibular segmental osteotomy, the entire mandibular symphyseal shape should be considered. Mandibular symphyseal contouring constitutes setting back the premolar region by segmental osteotomy, recession genioplasty, and chiseling out the protruding middle portion of the protruding chin. In 18 series of mild manibular prognathism in Asians patients, this procedure was used and satisfactory aesthetic results were obtained.     

下颌升支矢状劈开联合下颌下缘骨切除术矫正骨性反合并下颌骨过宽过长畸形

目的:总结正颌外科矫治下颌前突畸形的临床体会。方法:对12例下颌前突畸形合并下颌骨过宽过长患者同期进行了下颌升支矢状劈开下颌前突矫正术及下颌下缘骨切除术。结果:经术后1～2年随诊观察,12例患者均取得满意疗效,获得协调的上下颌关系,面下份形态轮廓恢复良好。结论:下颌前突畸形合并下颌骨过宽过长患者同期行下颌升支矢状劈开下颌前突矫正术及下颌下缘骨切除术,配合术前、术后的正畸治疗,降低了术中意外和术后并发症,弥补了传统行SSRO的不足,使患者恢复咬合功能的同时充分改善面部形态轮廓,达到面部整形美学标准。     

A comparison of lower lip hypoesthesia measured by trigeminal somatosensory-evoked potential between different types of mandibular osteotomies and fixation.

PURPOSE: The purpose of this study was to compare objectively, the recovery of hypoestheia of the lower lip following orthognathic surgery using different procedures (sagittal split ramus osteotomy [SSRO]) and intra-oral vertical ramus osteotomy (IVRO)) and fixation methods (monocortical plate fixation and bi-cortical plate fixation). Hypoesthesia was evaluated using the trigeminal somatosensory-evoked potential (TSEP). PATIENTS AND METHODS: The subjects consisted of 174 patients (348 sides) with mandibular prognathism with or without asymmetry, who underwent mandibular ramus osteotomies using different fixation types. The patients were divided into 4 groups. The OAM group consisted of 128 sides who had SSRO using the Obwegeser method with mono-cortical absorbable plate fixation, the ODTM group consisted of 84 sides who had the Obwegeser-Dal Pont method with mono-cortical titanium plate fixation, the OTB group consisted of 32 sides who had the Obwegeser method with bi-cortical titanium plate fixation and the VO group consisted of 104 sides who underwent IVRO according to the Bell method without fixation. Trigeminal nerve hypoestheia at the region of the lower lip was assessed bilaterally by the TSEP method. An electroencephalograph recording system (Neuropack Sigma; Nion Koden Corp., Tokyo, Japan) was used to analyze the potentials. Each patient was evaluated pre-operatively and then post-operatively at 1 and 2 weeks, 1, 3, and 6 months, and 1 year. RESULTS: The mean measurable period and standard deviation of TSEP of the lower lip in the OAM group was 5.2 +/- 9.9 weeks, 10.9 +/- 13.1 weeks in the ODTM group, 7.8 +/- 4.5 weeks in the OTB group, and 2.5 +/- 6.3 weeks in the VO group. There were significant differences between the OAM and ODTM groups (P < .0001), the ODTM and OTB groups (P = .0001), the OTB and VO groups (P = .0221), the OAM and VO groups (P < .0001), and the ODTM and VO groups (P < .0001). CONCLUSION: This study proved using objective measurements that the recovery period from hypoesthesia of the lower lip following orthognathic surgery was dependent on the surgical procedure. Recovery in lower lip hypoesthesia after IVRO was significantly earlier than SSRO.     

Surgical treatment of mandibular prognathism in collaboration with orthodontic treatment in Korea

Mandibular prognathism is defined by John Hunter as follows: The lower jaw projecting too far forward so that the foreteeth pass before those of the upper jaw, therefore disfigurement and malocclusion are two of the main facial characteristics. Other distinguishing features are the coexistence of class III malocclusion, incomplete closure of lip, deviation of the midline, and decrease of labiomental fold. Generally, the functional occlusal relationship and balanced facial harmony cannot be obtained by surgical or orthodontic treatment alone. Its success depends on careful conjoint, supplementary diagnostic, and treatment planning. As a cardinal principle the authors made the following combined surgical and orthodontic treatment plans: (1) Orthodontic treatment relocates and decompensates the malpositioned teeth (remove the masking effect of teeth) and, therefore, skeletal deformity is exposed maximally. (2) Surgical treatment eliminates the maximally exposed skeletal defect. Therefore, dramatic facial balance and functional occlusal relationship are obtained. Treatment planning includes the pre- and postoperative orthodontic treatment, lateral cephalometric prediction tracing (LCPT), and model surgery with dental cast. The authors made it easy with the use of an acrylic dental wafer to coordinate exact occlusal relationship after surgery. We treated mandibular prognathism by using Dautrey's modification of the sagittal split ramus osteotomy (SSRO) (10 cases) and intraoral vertical ramus osteotomy (IVRO) (5 cases) and sometimes additional genioplasty (2 cases). IVRO was used in those cases where (1) the amount of setback was more than 10 mm and (2) where there was a flat gonial angle. Otherwise SSRO was used. Late postoperative relapses were detected from 7 to 38 months (mean 19.6 months), followed up in some degree by cephalometrics, but the functional occlusal relationship proved to be stable. Conclusively, all the patients obtained satisfaction for their facial balance and functional occlusal relationship following combined surgical and orthodontic treatment.     

Comparison of maxillary stability after Le Fort I osteotomy for occlusal cant correction surgery and maxillary advanced surgery.

OBJECTIVE: To compare postoperative maxillary stability following Le Fort I osteotomy for the correction of occlusal cant as compared with conventional Le Fort I osteotomy for maxillary advancement. STUDY DESIGN: The subjects were 40 Japanese adults with jaw deformities. Of these, 20 underwent a Le Fort I osteotomy and intraoral vertical ramus osteotomy (IVRO) to correct asymmetric skeletal morphology and inclined occlusal cant. The other 20 patients underwent a Le Fort I osteotomy and sagittal split ramus osteotomy (SSRO) to advance the maxilla. Lateral and posteroanterior cephalograms were taken postoperatively and assessed statistically. Thereafter, the 2 groups were followed for time-course changes. RESULTS: There was no significant difference between the 2 groups with regard to time-course changes during the immediate postoperative period. CONCLUSION: This suggests that maxillary stability after Le Fort I osteotomy for cant correction does not differ from that after Le Fort I osteotomy for maxillary advancement.     

下颌升支矢状劈开不同截骨术矫治下颌前突的对比分析

目的探讨改良和经典下颌升支矢状劈开截骨术在矫治下颌前突方面的适应证及优缺点。方法1997年1月~2005年1月,采用下颌升支矢状劈开截骨术矫正真性下颌前突及下颌前突合并其他部位畸形患者95例,男34例,女61例。年龄15~44岁,平均21.3岁。单纯下颌前突53例,下颌前突合并偏颌28例,上颌后缩11例,大舌2例,双侧颧骨突出1例。X线头影测量:蝶鞍点-鼻根点-上齿槽座点角(sella-nasion-Apoint,SNA)80~83°,蝶鞍点-鼻根点-下齿槽座点角(sella-nasion-Bpoint,SNB)80~84°,上齿槽座点-鼻根点-下齿槽座点角(Apoint-nasion-Bpoint,ANB)-3~1°。采用改良术式43例,经典术式52例。结果患者术后面型及咬关系均得到明显改善。经典术式组患者术后单侧或双侧下唇区感觉障碍9例,劈骨时单侧下颌升支意外骨折1例,严重出血1例,术后切口感染1例,畸形轻度复发3例。改良术式组患者术后下唇区感觉障碍2例,畸形轻度复发1例,无颌骨意外骨折、严重出血和术后感染等并发症发生。随访3个月~7年,复查X线并进行头影测量:SNA角81~83°,SNB角78~81°,ANB角1~4°。结论改良术式是下颌前突尤其是严重前突和伴有偏颌患者升支矢状劈开旋转、后退比较理想的一种手术方式,而对轻度至中度下颌前突患者则既可应用改良术式也可应用经典术式。     

Posterior vertical deficiencies of the mandible: presentation of a new corrective technique and retrospective study of 21 cases.

PURPOSE: The hyperdivergent (high-angle forms of Class II) dentoskeletal deformities are difficult entities to treat. The purpose of this study was to describe and evaluate the use of a new surgical procedure to lower the posterior portion of the occlusal plane during a sagittal split osteotomy of the mandibular ramus, to correct a Class II malocclusion resulting from insufficient development of the mandibular ramus. PATIENTS AND METHODS: During a sagittal split osteotomy of the mandibular ramus, the pterygomasseteric sling was completely incised in 21 patients, to treat Class II malocclusion with vertical ramus deficiency. The patients were evaluated clinically, radiologically, and cephalometrically. RESULTS: In all cases, the posterior occlusal plane was successfully lowered, with stable occlusal results, both vertically and sagittally. An increase in the vertical dimension of the ramus remains somewhat more difficult to document. CONCLUSIONS: Sagittal split osteotomy of the mandibular ramus with complete incision of the pterygomasseteric sling makes it possible to lower the posterior occlusal plane in cases of posterior vertical mandibular deficiency. This technique, which offers a nonexternal approach, represents a useful additional option for the treatment of these dysmorphoses.     

下颌升支矢状劈开截骨术矫治下颌前突并发症的原因和预防

目的:探讨应用下颌升支矢状劈开截骨术矫治下颌前突并发症的原因及预防措施。方法:对1997年1月～2005年1月于我院采用下颌升支矢状劈开截骨术矫正的下颌前突及下颌前突合并其他部位畸形患者95例术后并发症进行回顾性分析。结果:术后单侧或双侧下唇区感觉障碍11例,严重出血1例,劈骨时单侧下颌升支意外骨折1例,术后切口感染1例,畸形轻度复发4例。结论:下齿槽神经损伤、出血、骨折、感染和复发是下颌升支矢状劈开截骨术常见并发症,不仅影响手术效果,而且可能危及生命。必须根据发生原因采取有效的预防措施,才能降低或避免其发生。     

下颌支矢状骨劈开术中下颌前突者下颌支的CT测量

目的 用CT扫描的方法来描述下颌支骨松质分布和骨皮质厚度变化情况,以此来估计下颌支矢状骨劈开术舌侧骨切开的位置、深度和方向.方法 45例实施下颌支矢状骨劈开术的骨性Ⅲ类下颌前突患者,术前进行上下颌骨CT扫描.从下颌小舌平面开始每隔2.5mm为一层面进行测量,向上20 mm,在每一层面测量骨皮质的厚度和骨松质的分布情况.结果 下颌支上部骨松质分开的占37.5%,骨松质在任何一层均未分开的占62.5%.在下颌小舌上5 mm平面,舌侧骨皮质的厚度从前向后逐渐变薄,平均厚度1.55 min,下颌小舌距离升支后部骨皮质融合处的平均距离为9.45mm.结论 舌侧骨切开应位于下颌小舌上5mm以内的区域,在下颌小舌后方9.45 mm以内切开,骨切开线由后向前可轻度向下,切开深度2 mm左右,向前逐渐加深.     

口内入路改良下颌升支矢状劈开截骨术矫治下颌前突

目的:探讨改良下颌升支矢状劈开截骨术(SSRO)和经典SSRO何种术式是矫治下颌前突的更为合适的手术方式。方法:采用改良SSRO或经典SSRO矫正真性下颌前突及下颌前突合并其他部位畸形患者95例,采用改良术式矫正43例,经典术式矫正52例。结果:经典术式组术后单侧或双侧下唇麻木9例,劈骨时单侧下颌升支意外骨折1例,严重出血1例,术后切口感染1例,术后复发3例。改良术式组术后感觉障碍2例,术后复发1例,无颌骨意外骨折、严重出血、术后感染等并发症发生。随访3月～7年,所有患者术后面型及咬合关系均得到明显改善。结论:改良术式具有经典术式无法比拟的优点:操作方便,手术时间短,术后恢复快;手术风险小;增加了下颌体的后退量;术中术后并发症少。因而是下颌前突尤其是严重前突和伴有偏颌畸形患者升支矢状劈开旋转、后退的首选术式,配合正规及时的术前、术后口腔正畸治疗,具有更为广阔的应用前景。     

弧形截骨术和外板劈除术对下颌角形态变化的比较

目的探讨和比较下颌角弧形截骨成形术后和下颌角外板劈除术后对下颌角肥大患者下颌角的形态变化差异。方法对下颌角肥大行弧形截骨成形术的30例和行下颌角外板劈除术后的20例的头颅正、侧位片进行测量比较。结果下颌角弧形截骨成形术使下颌角间距变小,下颌角角度变钝,下颌升支长度变短,下颌角点向前上移位,下颌角区的下颌骨最大宽度变小,下颌骨升支及体部变窄;下颌角外板劈除法可以使下颌角间距变小,而下颌升支长度,下颌角区的下颌骨最大宽度,下颌骨升支及体部的宽度均无明显变化。结论下颌角弧形截骨成形术对面下部正面观和侧面观均有较大改善,下颌角外板劈除术主要对面下部正面观有较大改善,在进行下颌角肥大成形术时,应注意手术适应证的选择。     

内窥镜辅助下口内入路下颌角截骨术29例体会

目的探讨内窥镜辅助下口内入路下颌角截骨改脸形的手术方法。方法内窥镜辅助下,经口内入路,先用小圆钻钻孔,之后用来复锯截除下颌骨外板、摆动锯长斜形或弧形截骨。结果本组共29例患者,术后随访3个月以上,效果满意26例,不满意3例。术后伤口均Ⅰ期愈合,开口度、口型及咀嚼功能均正常,无血管损伤、下齿槽神经损伤、下颌骨意外骨折等严重并发症发生。结论内窥镜辅助下口内切口下颌角截骨重塑面部轮廓手术是安全有效的手术方法。