Endoscopic vertical ramus osteotomy: a long-term prospective study

The purpose of this prospective study was to evaluate the outcomes of endoscopic vertical ramus osteotomy (EVRO) with rigid fixation for the treatment of mandibular prognathism or asymmetry. Inclusion criteria were age >15 years, adequate clinical and radiographic documentation, and minimum postoperative follow-up of 3 years. Exclusion criteria were refusal to consent, rheumatoid arthritis, steroid use, and smoking. Demographic data, pre-operative (T0), immediate postoperative (T1), and latest follow-up (T2) clinical examinations and cephalometric analysis, procedure data, complications, and length of hospital stay (LOS) were documented. Ten fulfilled the inclusion criteria. Diagnoses included mandibular hyperplasia (n = 5), stable condylar hyperplasia (n = 4), and mandibular asymmetry secondary to condylar resorption (n = 1). In total, 17 EVROs were performed. The mean operative time was 33 min per side. Mean mandibular setback was 4.7 mm. Mean LOS was 1.9 days. Latest follow-up ranged from 3 to 5 years. Skeletal stability was confirmed in nine patients. One patient exhibited recurrence of mandibular prognathism at 5 years due to late growth. No VII nerve deficits were encountered. Inferior alveolar nerve (IAN) paresthesia was noted in four patients, which resolved postoperatively. EVRO was fast and resulted in minimal blood loss, quick recovery, and skeletal stability.     

Surgical morbidities of sagittal split ramus osteotomy versus intraoral vertical ramus osteotomy for the correction of mandibular prognathism: a randomized clinical trial

The sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) are two common orthognathic procedures for the treatment of mandibular prognathism. This randomized clinical trial compared the surgical morbidities between SSRO and IVRO for patients with mandibular prognathism over the first 2 years postoperative. Ninety-eight patients (40 male, 58 female) with a mean age of 24.4 ± 3.5 years underwent bilateral SSRO (98 sides) or IVRO (98 sides) as part or all of their orthognathic surgery. IVRO presented less short-term and long-term surgical morbidity in general. The SSRO group had a greater incidence of inferior alveolar nerve deficit at all follow-up time points (P <  0.01). There was more TMJ pain at 6 weeks (P =  0.047) and 3 months (P =  0.001) postoperative in the SSRO group. The SSRO group also presented more minor complications, which were related to titanium plate exposure and infection. There were no major complications for either technique in this study. Despite the need for intermaxillary fixation, IVRO appears to be associated with less surgical morbidity than SSRO when performed as a mandibular setback procedure to treat mandibular prognathism.     

下颌升支垂直截骨在髁状突手术中的应用

目的：观察下颌升支垂直截骨间接治疗髁状突疾患的疗效。方法：采用下颌升支垂直截骨方式间接治疗髁状突疾患19例，其中髁状突良性肥大2例，髁状突骨瘤4例，颞下颌关节骨性强直3例，髁状突骨折10例。结果：所有患者张口度均接近或达到正常，无关节疼痛及弹响症状，随访期内无1例复发。结论：下颌升支垂直截骨间接髁状突整复是治疗髁状突疾患的一种可选择的、有效的方法。     

The stability of bilateral sagittal ramus osteotomy and vertical ramus osteotomy after bimaxillary correction of class III malocclusion

Introduction

The purpose of this retrospective cephalometric study was to compare the stability of bilateral sagittal split osteotomy (BSSO) with extra-oral vertical ramus osteotomy (VRO) after correction of class III malocclusion by means of bimaxillary orthognathic surgery.

Methods

The sample comprised 51 consecutively treated patients, 38 females and 13 males, with a mean age of 19.1 years. All had a one-piece Le Fort I osteotomy with maxillary advancement and mandibular setback. VRO was performed in 30 cases, and BSSO was performed in 21 cases. Lateral cephalograms were obtained before surgery, within 1 week of surgery and 1 year after surgery.

Results

The mean forward movement of the maxilla was 5.6 mm in both groups (p < 0.001). The mean horizontal surgical change in the VRO group was 4.4 mm (p < 0.001), and in the BSSO group it was 5.4 mm (p < 0.001). In the VRO group, the horizontal relapse was 1.2 mm (p < 0.001), and in the BSSO group, it was 1.4 mm (p < 0.001).

Conclusion

There was no difference in the stability between the BSSO and VRO groups. The average relapse in the whole sample was 26% of the surgical movement.     

Comparison of osseous healing after sagittal split ramus osteotomy and intraoral vertical ramus osteotomy

The sagittal split ramus osteotomy (SSRO) is generally associated with greater postoperative stability than the intraoral vertical ramus osteotomy (IVRO); however, it entails a risk of inferior alveolar nerve damage. In contrast, IVRO has the disadvantages of slow postoperative osseous healing and projection of the antegonial notch, but inferior alveolar nerve damage is believed to be less likely. The purposes of this study were to compare the osseous healing processes associated with SSRO and IVRO and to investigate changes in mandibular width after IVRO in 29 patients undergoing mandibular setback. On computed tomography images, osseous healing was similar in patients undergoing SSRO and IVRO at 1 year after surgery. Projection of the antegonial notch occurred after IVRO, but returned to the preoperative state within 1 year. The results of the study indicate that IVRO is equivalent to SSRO with regard to both bone healing and morphological recovery of the mandible.     

下颌升支垂直/斜行骨切开术涉及骨性标志的测量分析

目的测量分析成年人下颌升支与垂直或斜行骨切开术相关的骨性标志。方法收集成年离体下颌骨标本105例(男54例,女51例)。测量下颌孔最下点、下颌孔后点与升支后缘的水平距离;并观察下颌孔最下点与下颌第二磨牙牙合平面的垂直向关系,翼肌粗隆最上点与下颌孔最下点的垂直向关系,以及下颌升支外侧隆突存在的比例。结果下颌孔最下点到升支后缘的平均距离男性为16.12mm,女性为16.03mm;最小距离男性为11.20mm,女性为10.68mm。下颌孔后点到升支后缘的水平距离男性为13.50mm,女性为13.60mm;最小距离男性为10.06mm,女性为10.18mm。90.17%的标本下颌孔最下点低于下颌第二磨牙牙合平面;85.34%的标本下颌升支翼肌粗隆最上点超越下颌孔最下点平面;72.41%的升支外侧隆突明显存在。结论下颌孔最下点及后点到升支后缘的水平距离男女相似,无性别差异。在下颌第二磨牙牙合平面水平距升支后缘8~10mm作骨切开线一般可以避开下齿槽神经血管束;升支内侧翼内肌附着有利于近心骨段的血液供应。     

Extraoral subcondylar ramus osteotomy for correction of mandibular prognathism: The surgical technique and complications

1178 patients with mandibular prognathism and/or asymmetry, in some cases combined with maxillary retrognathism, were treated by extraoral horizontal or oblique ramus osteotomy during the period from 1939 to 1989. The described percutaneous retromandibular approach is a simple, rapid and reliable technique which can usually be performed under local anaesthesia. Very few complications, particularly neurological, were observed. These aspects justify consideration of this technique when indications for a simple, straight set-back procedure of the mandible exist, and there is no tendency to bite-opening. However, the method demands intermaxillary fixation for 6-9 weeks postoperatively.     

Three-dimensional changes of proximal segments in facial asymmetry patients after bilateral vertical ramus osteotomy

The intraoral vertical ramus osteotomy (IVRO) is a useful technique for mandibular setback surgery. However, there is a tendency for lateral flaring of the proximal segments on the non-deviation side after the correction of mandibular asymmetry with this technique. The purpose of this retrospective study was to evaluate the positional changes of the proximal segments after IVRO setback in skeletal class III patients with asymmetry, using preoperative and postoperative computed tomography scan data, and to apply the results in clinical practice. A total of 28 skeletal class III patients with asymmetry who underwent bimaxillary orthognathic surgery were included. A three-dimensional cone beam computed tomography scan was obtained preoperative, at 1 month postoperative, and at 1 year postoperative. At 1 month after the surgery, the proximal segments showed an outward rotation, lateral flaring, and anterior rotation of the condylar head. All postsurgical directional changes had returned to the preoperative state at 1 year postoperative, and there was no statistically significant difference in postoperative angulation changes between the two sides. The results showed no statistical differences in the positional changes of the proximal segments between the deviation and non-deviation sides. This study reaffirms the benefits of the IVRO for a minimal bony interference between the proximal and distal segments in three dimensions, including mandibular asymmetry cases.     

下颌升支后缘上移联合面部轮廓整形术同期治疗髁突骨软骨瘤及继发颌骨畸形

目的：研究在髁突骨软骨瘤患者病变髁突切除后,联合采用下颌升支后缘切开上移术和面部轮廓整形术同期治疗其继发颌骨畸形的手术效果,并探讨其临床应用价值。方法选择8例髁突骨软骨瘤的患者,全部采用病变髁突切除+下颌升支后缘切开上移术重建髁突+下颌轮廓整形手术,并辅助术后正畸或颌间结扎,同期治疗患者的髁突疾病及面部不对称问题。结果所有患者对术后效果都比较满意,患者面型不对称畸形、咬合及关节功能异常均得到很大改善,且随访期间髁突骨软骨瘤未见复发。结论髁突骨软骨瘤的病变髁突切除术后同期采用下颌升支后缘切开上移术+下颌轮廓整形手术的联合使用不仅可以摘除肿瘤,还可以有效的改善患者的面容,取得良好的治疗效果。     

Fixation methods in sagittal split ramus osteotomy: a systematic review on in vitro biomechanical assessments

The aim of this systematic review was to assess the stability of rigid internal fixation (RIF) techniques in sagittal split ramus osteotomy (SSRO) based on in vitro biomechanical assessments, with particular interest in large mandibular advancements. In general, RIF methods can be divided into three groups: bicortical screws, miniplates, and a combination of the two. An electronic search of the PubMed, CINAHL, and Embase databases was performed, and studies published between January 2003 and March 2018 were screened for inclusion. Comparative studies with an in vitro experimental design, using biomechanical assessments to measure the stability of RIF methods in SSRO, were included. Of 104 unique studies identified in the initial search, 24 were included. Twenty-two of these 24 studies analyzed an advancement of the mandible of 7 mm or less. The use of a single four-hole or six-hole miniplate was less stable than the use of bicortical screws, hybrid techniques, double miniplates, or grid plates. Two studies analyzed advancements of 10 mm, for which two miniplates placed in parallel and a grid plate showed most stability. Although there was agreement between studies with regard to results, more biomechanical studies are required to quantify the stability of fixation methods in larger mandibular advancements.     

The different effects of intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO) on mandibular border movement

Objectives: This study investigated the different effects of intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO) on mandibular border movement.

Methods: The participants included 22 patients receiving IVRO and 22 patients receiving SSRO who were treated at Okayama University Hospital. Their mandibular border movement was evaluated in three dimensions with 6° of freedom using an optical recording system.

Results: A strong correlation between condylar and lower incisor movement was observed during maximum jaw protrusion and laterotrusion. Significant improvements in condylar and lower incisor movement were detected after orthognathic surgery during maximum jaw protrusion and laterotrusion in the IVRO group and during maximum jaw protrusion in the SSRO group.

Discussion: IVRO likely achieves greater improvement in jaw movement than SSRO. Therefore, the application of IVRO could be considered in the treatment of patients with jaw deformities featuring temporomandibular joint problems.     

Stability of fixation methods in large mandibular advancements after sagittal split ramus osteotomy: an in vitro biomechanical study

Sagittal split ramus osteotomy (SSRO) with large mandibular advancements is a common surgical procedure and could be indicated for patients with sleep apnoea. As a large variety of fixation methods is used for the stabilisation of SSRO, a biomechanical test model was used to analyse which fixation technique was most stable. For this in vitro study, 80 polyurethane hemimandibles with a prefabricated SSRO were used as substrates. Loads in Newtons were recorded at displacements of the mandibular incisive edge at 1 mm, 3 mm and 5 mm. The samples were divided into two groups: mandibular advancements of 10 mm and 15 mm. In both groups, four fixation techniques were used: (A) one four-hole miniplate; (B) two four-hole miniplates; (C) one four-hole miniplate plus one bicortical screw; and (D) three bicortical screws in an inverted-L arrangement. In group 1, three bicortical screws resulted in the best stability, and in group 2, two miniplates resulted in the best stability. The use of two miniplates did not show significant differences between both groups. Other fixation methods showed more stability with 10 mm advancements. This study therefore suggests that in SSRO with advancements exceeding 10 mm, the use of two miniplates is the optimal means of providing rigid fixation.     

Tongue–palatal contact changes in patients with skeletal mandibular prognathism after sagittal split ramus osteotomy: an electropalatography study

The purpose of this study was to investigate the changes in tongue–palatal contact patterns using electropalatography (EPG) before and after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. Nine clients who underwent SSRO for mandibular setback and seven control subjects were participated in this study. Tongue–palatal contact patterns for /t/, /s/ and /k/ production were investigated using EPG before surgery and 3 months after surgery. The mean value of whole total of palate contact (WT) in the maximum contact frame was examined before and after SSRO. The correlation quantity between the change of center of gravity (COG) value and the amount of mandibular setback was also evaluated. The mean value of WT for /t/ and /s/ significantly increased after SSRO, and the EPG pattern became normal. However, a remarkable change in WT for /k/ was not observed, and the mean value was significantly larger in the SSRO group before and after surgery than in the control group. A negative correlation between COG variation and the amount of mandibular setback for /t/ and positive correlation for /s/ was observed. This study demonstrated that tongue–palatal contact patterns for /t/ and /s/ articulation improved clearly after SSRO. There was a significant correlation between COG variation and the amount of mandibular setback. However, no significant change was detected through perceptual assessment before and after SSRO. Further investigation is needed to determine whether these results will change over time.     

Stability after sagittal split ramus osteotomy without post-operative maxillomandibular fixation in the treatment of prognathic patients with asymmetric mandibles

This study was designed to examine the post-operative stability in prognathic patients with mandibular asymmetry, who underwent sagittal split ramus osteotomy (SSRO) of the mandible and titanium screw fixation without post-operative maxillomandibular fixation (MMF). Twenty prognathic patients were examined. An appliance for repositioning the proximal segment was applied during surgery in all patients. Ten patients with symmetric mandibles underwent post-operative MMF with stainless steel wire and intermaxillary rubber traction after removal of MMF (Group I), and the other 10 patients with asymmetric mandibles received only intermaxillary rubber traction post-operatively (Group II). Posteroanterior cephalograms were obtained pre-operatively; 2–3 days post-operatively; and 3, 6, and 12 months after surgery. Changes in the positions of the gonion points (Go) and upper and lower incisors (U-1 and L-1) were examined. In both groups, the Go tended to shift laterally, as a consequence of the operation. Although the tendencies of the post-operative changes in (Go) points of Groups I and II were different, statistical analyses revealed no differences between the two groups. At the late stage of follow-up, the absolute value of the change in L-1 tended to be larger in Group II than in Group I, but without statistical significance. This study suggests that post-operative change in prognathic patients with asymmetric mandibles treated without post-operative MMF is comparable to that in patients with symmetric mandibles treated with post-operative MMF. Therefore, post-operative MMF might be avoided, even in prognathic patients with asymmetric mandibles.     

Extraoral vertical ramus osteotomy combined with internal fixation for the treatment of mandibular deformities

Extraoral vertical ramus osteotomy (EVRO) is used in orthognathic surgery for the treatment of mandibular deformities. Originally, EVRO required postoperative intermaxillary fixation (IMF). EVRO has been developed using rigid fixation, omitting postoperative IMF. We examined retrospectively the long-term stability and postoperative complications for patients with mandibular deformities who underwent EVRO with internal rigid fixation. Patients who were treated with EVRO for a mandibular deformity in the period 2008–2017 at the Clinic of Oral and Maxillofacial Surgery, Mölndal, Sweden were included (N = 26). Overjet and overbite were calculated digitally and cephalometric analyses were performed preoperatively, and at three days, six months, and 18 months postoperatively. There was a general setback of the mandible, decreased gonial angle and reduced degree of skeletal opening. Excellent dental and vertical skeletal stabilities were seen up to 18 months postoperatively, although relapse was seen sagitally up to six months postoperatively. Since the overjet did not show any significant change over time, the sagittal skeletal changes have been attributed to dental compensation. There was no permanent damage to the facial nerve and 5.8% neurosensory damage to the inferior alveolar nerve was observed.     

下颌支矢状劈开术与下颌管位置关系的应用解剖学研究

目的研究下颌管在下颌骨内的重要行径和位置关系。方法选用带软组织50具完整的头颈标本,分别在下颌第三磨牙后缘的垂直线、磨牙后三角尖至下颌角连线呈额状位锯开下颌骨,观察下颌管的解剖。结果下颌管是下颌骨的骨松质内形成较薄的骨密质骨管。下颌管在下颌骨第三磨牙后缘切面的位置靠内侧型占90%,中间型占10%;在连线切面的位置靠内侧型占84%,中间型占16%。结论了解下颌管在下颌骨内的重要毗邻关系,可以减少因下牙槽神经损伤造成口裂以下粘膜和皮肤的感觉障碍。     

Remodelling pattern of the ramus on submentovertex cephalographs after intraoral vertical ramus osteotomy

The aim of this study was to evaluate postoperative changes in proximal segments and condyles on the transverse plane after intraoral vertical ramus osteotomy. This is a retrospective study that included 200 subjects operated on, from 2003 to 2010, from whom we compared preoperative and postoperative (7 days, and 1, 3, 6, and 12 months) submentovertex radiographs. Postoperative positional changes in the condyles showed a mean (SD) of 15.05 (8.97)° lateral rotation, which slowly returned towards the original position. However, 4.53 (6.03)° lateral rotation remained on the postoperative radiographs at 1 year. There were no remarkable differences in intercondylar distance at any given time interval, which showed pure rotation of condyles without any bodily shift. The length of horizontal overlapping was also increased after operation, and was later decreased by 48% on postoperative radiographs at 1 year through the remodelling process. Condyles had rotated laterally without a lateral shifting movement only after intraoral vertical ramus osteotomy. Further studies to evaluate the physiological effects of rotational movement of the condyles after the operation in patients with symptoms in the temporomandibular joint are indicated.     

The influence of bilateral sagittal split ramus osteotomy on submental‐cervical aesthetics

The effect of orthodontic‐surgical treatment on submental‐cervical region was evaluated in a very limited number of studies. The aim of this study was to evaluate submental‐cervical soft tissue contour changes following mandibular advancement and set‐back procedures via bilateral sagittal split ramus osteotomy. Sixty‐seven patients were included in this study. Group 1 consisted of 27 skeletal Class II patients who underwent mandibular advancement surgery, whereas Group 2 consisted of 40 skeletal Class III patients who underwent mandibular set‐back surgery. Various linear and angular measurements were performed on pre‐operative and sixth month post‐operative cephalometric radiographs. A new method was used to evaluate the amount of sagging at submental region. The submental length did not change in Group 1; however, it decreased significantly in Group 2 (P < 0·05). The angle between submental plane and facial plane decreased to 95·9° from 98·8° in Group 1(P < 0·05), whereas it increased to 93·1° from 88·2° in Group2 (P < 0·05). The change of submental soft tissue sag was almost stable in Group 1, while 0·34 mm increase of sag was observed in Group 2. This increase was not statistically significant (P > 0·05). Mandibular set‐back and advancement procedures do not remarkably change the submental sag following approximately 6 mm jaw movement. Although mandibular advancement did not significantly effect submental length, soft tissue followed mandibular set‐back with a ratio of 1:1 at C‐point to projection of soft tissue pogonion and 1:0·7 at C‐point to soft tissue menton distances.     

Considerations in correction of mandibular protrusion by intra-oral vertical ramus osteotomy

This case report presents a case that underwent orthognathic treatment with intra-oral vertical ramus osteotomy (IVRO). The patient was a 19-year-old female with mandibular protrusion and severe maxillary anterior crowding. The overbite was +0.5 mm and the overjet −1.5 mm. She had orofacial pain and tenderness of the temporomandibular joints (TMJ) and surrounding muscles. The pre-surgical orthodontic treatment included the extraction of the maxillary right lateral incisor, maxillary right second premolar, maxillary left canine, mandibular left second molar and mandibular right second premolar. After 18 months of pre-surgical orthodontic treatment, the left and right sides of the mandible were set back 8 and 6 mm, respectively, via IVRO to improve mandibular protrusion. The total treatment period was 26 months. The patient showed the backward reaction of the mandible, which occurred after release of the maxillo-mandibular fixation. The usage of the Class II elastics during the post-surgical phase to maintain the overjet made the inclination of the maxillary incisors more lingual.