Feasibility of osteotomies in fibrous dysplasia of the jaws

Two examples are presented of osteotomies performed simultaneously with surgical recontouring in cases of fibrous dysplasia of the jaws. Osteotomies are necessary when a coexistent discrepancy in jaw relationship is present. This provides a functional as well as aesthetic result. Rigid miniplate fixation was utilised, and dysplastic bone healing was uneventful, and found clinically not to differ from that of normal bone. Osteotomy is thus feasible in dysplastic bone, and may complement recontouring in achieving a better result.     

The stability of facial osteotomies. Part 5. Maxillary advancement with miniplate and screw fixation

Surgical repositioning of the dento-skeletal components of the middle-third of the face, combined with appropriate orthodontic treatment, can be used to improve function and aesthetics. However, the attainment of three-dimensional stability following corrective jaw surgery continues to be a major problem in the postsurgical period.
This paper examines the short-term (six weeks postoperative) and long-term (12 months postoperative) horizontal skeletal stability of Le Fort I maxillary advancement in 15 patients. The mean horizontal advancement of the maxilla was 8.76 ± 0.99 mm. Six weeks later, a mean relapse of 0.22 ± 0.19 mm was identified. The mean relapse at long-term follow-up was 0.61 ± 0.26 mm (6.96%).
These results indicate that rigid miniplate and screw fixation of Le Fort I osteotomy undertaken to correct horizontal mid-dentofacial deficiency is both statistically and surgically predictable and stable when reviewed up to twelve months after surgery.     

Quantitative evaluation of symmetry after navigation-guided surgical recontouring of zygomatic fibrous dysplasia: a comparative study

Zygomatic fibrous dysplasia is a slowly progressive disorder of bone, which commonly causes facial asymmetry. Precise surgical recontouring can effectively improve facial aesthetics. The aim of this study was to quantitatively evaluate the effectiveness of surgical navigation guidance in correcting zygomatic asymmetry. The study included 26 patients with unilateral zygomatic fibrous dysplasia who underwent bony recontouring. They were divided into two groups according to the use of intraoperative surgical navigation (navigation group and conventional group; n = 13 in each group). Clinical outcomes were evaluated using three-dimensional computed tomography. Six pairs of landmarks were identified, and the coordinates were used to calculate asymmetry indices. The curvature of protruding regions in the surgical area was measured to determine facial skeletal symmetry in three dimensions. The results were compared between the groups. All patients recovered uneventfully and their facial symmetry and aesthetics improved. For three of the six pairs of landmarks, symmetry was better in the navigation group than in the conventional group (all P ≤  0.02). The postoperative curvature ratios were better (more symmetrical) in the navigation group (P =  0.01). Surgical navigation enhances postoperative facial symmetry. However, the clinical significance of this enhancement when compared to conventional non-navigation surgery needs further investigation.     

The stability of facial osteotomies. 4. Maxillary and mandibular (with or without chin) advancement with rigid internal fixation

The short-term (6 weeks postoperative) and long-term (12 months postoperative) horizontal skeletal stability of combined maxillary and mandibular advancement was evaluated by cephalometric analysis of 15 patients.
The mean horizontal advancement of the maxilla was 5.84 mm. Six weeks later a mean horizontal relapse of 0.03 mm (0.05%) was identified. The mean horizontal relapse at long-term follow-up was 0.59 mm (10.1%).
The mean horizontal advancement of the mandible was 12.35 mm at menton and 12.65 mm at pogonion. At 6 weeks, mean horizontal relapse, respectively at the above landmarks, was 0.11 mm and 0.21 mm (1.3%). The mean horizontal relapse at long-term follow-up was 2.19 mm and 1.98 mm (16.6%) respectively for the same landmarks.
Subjectively and objectively, improvements were seen in facial aesthetics and dental occlusion. The results indicate that rigid fixation of osteotomies undertaken to correct 'horizontal facial deficiency' is a surgically predictable and relatively stable procedure when reviewed up to 12 months after surgery.     

Neurofibromatosis and fibrous dysplasia manifesting in the same patient: a rare case report

Neurofibromatosis and fibrous dysplasia show the presence of café‐au‐lait spots, bone lesions, and endocrinopathies. There has been speculation whether neurofibromatosis and fibrous dysplasia are different manifestations of the same disease or if these conditions are in some way related. We provide a case of whether neurofibromatosis and fibrous dysplasia complicated by hyperparathyroidism and osteoporosis.     

手术治疗颅颌面部骨纤维发育不良对视力影响的系统评价

目的: 探讨手术治疗颅颌面部骨纤维发育不良对患者视力的影响。方法: 计算机检索PubMed、Web of Science、Cochrane 图书馆和Cochrane临床试验注册中心、中国知网、维普数据库和万方数据库。纳入对颅颌面部骨纤维发育不良患者行手术治疗的研究,以未出现视力损伤患者为试验组,出现视力损伤患者为对照组,提取手术后出现视力损伤患者数合并数据进行meta分析。结果: 采用固定效应模型进行meta分析,未出现视力损伤时,进行手术治疗完全不会增加视力损伤的发生[OR=0.39,95%CI (0.18~0.86),P=0.02],各研究之间同质性良好[Chi²=8.63, df=9(P=0.47); I²=0%],且研究不存在发表偏倚。结论: 手术治疗颅颌面部骨纤维发育不良并不会增加患者视力受损的可能性。     

颌骨骨纤维异常增殖症GNAS基因突变分析及其间充质细胞体外生物学特征

［摘要］ 目的 探讨颌骨骨纤维异常增殖症( fibrous dysplasia, FD)GNAS基因突变的分析方法;细胞学实验比较正常颌骨与FD患者颌骨来源骨髓间充质干细胞（bone marrow stromal cells,BMSCs）的生物学特征及其差异,为进一步研究FD的病因及发病机制奠定基础。方法 对我院2006—2016年间40例FD患者的石蜡标本切取组织切片并提取DNA,通过等位基因特异性 PCR及测序,分析GNAS基因突变特征。在患者知情同意前提下,收集FD病灶切除术中取得的病灶区颌骨组织,贴壁培养法获得 BMSCs;CCK8检测细胞增殖能力;茜素红染色检测矿化结节形成能力;Western blot及real time PCR检测RUNX2等成骨分化相关基因的表达。结果 本组40例FD患者中35例GNAS基因发生突变,突变率为87.5%,其中R201H占71.4%,R201C占28.6%。与正常颌骨BMSCs相比,FD BMSCs细胞形态无明显差异;但FD BMSCs具有更强的增殖能力;在成骨诱导液的作用下,FD BMSCs 具有更弱的成骨分化能力,表现为相关成骨分化相关基因的低表达及较弱的矿化结节形成能力。结论 FD患者GNAS基因存在特异性突变,等位基因特异性PCR 是检测该突变的简便、可靠方法之一;细胞学研究表明FD BMSCs不仅表现为高增殖活性,且其成骨分化能力显著下降,提示FD的发病机制可能与成骨分化过程障碍有关,对进一步认识FD 的发病机制具有重要意义。     

Intermaxillary fixation screw for endotracheal tube fixation in the edentulous patient with facial burns

Endotracheal tube fixation in patients with severe facial burns and edentulism is a challenge. We describe a simple and elegant method to secure the endotracheal tube in such patients by means of an intermaxillary fixation screw.     

Three-dimensional versus standard miniplate fixation in the management of mandibular angle fractures: a systematic review and meta-analysis

The aim of the present study was to test whether there is a significant difference in the clinical outcomes between standard and three-dimensional (3D) miniplate fixation in the management of mandibular angle fractures (MAFs). An electronic search without date and language restrictions was performed in October 2013. Inclusion criteria were studies in humans including randomized controlled trials, controlled clinical trials, and retrospective studies, with the aim of comparing the two techniques. Six studies were included. The meta-analyses revealed statistically significant differences for the incidence of hardware failure and postoperative trismus. There were no significant differences in the incidence of postoperative infection, malocclusion, wound dehiscence, non-union/malunion, or paresthesia. The cumulative odds ratio was 0.42, meaning that the use of 3D miniplates in the fixation of MAFs decreases the risk of the event (postoperative complication) by 58%. The results of this meta-analysis showed lower postoperative complication rates with the use of 3D miniplate fixation in comparison with the use of standard miniplate fixation in the management of MAFs.     

Computer-guided contouring of craniofacial fibrous dysplasia involving the zygoma using a patient-specific surgical depth guide

The aim of this study was to introduce a new computer-guided technique for contouring and shaving of craniofacial fibrous dysplasia involving the zygoma. Computer-guided contouring was performed for five patients with unilateral craniofacial fibrous dysplasia involving the zygoma, using a patient-specific surgical depth guide. This patient-specific guide with depth holes was virtually designed for each patient based on mirroring of the unaffected side. The guide was printed using rapid prototyping. In the surgical theatre, the guide was seated in place and implant drills were inserted through the guide holes, creating depth holes according to the preoperative planning. Bone removal was then continued using surgical burs and/or bone chisels, connecting the guiding depth holes. Satisfaction with facial aesthetics was evaluated by the patients using a Likert scale, and by the surgeons using the Whitaker rating scale. All patients were satisfied with the postoperative facial aesthetics. Four patients were rated category I on the Whitaker rating scale, and one patient as category II. In conclusion, this patient-specific surgical depth guide appears to offer a solution for the unpredictability of conventional bone removal in unilateral craniofacial fibrous dysplasia, especially in three-dimensional multiplanar areas such as the zygoma. Further investigations are required.     

Clinico-radiological study of fifty cases of fibrous dysplasia in the jaw bones

The purpose of this study was to report clinical and radiological findings of patients with fibrous dysplasia of the jaws. The subjects of this study were 50 patients with 54 lesions reported to have fibrous dysplasia at the faculty of Dentistry, Chulalongkorn University during 1971–1994. The clinical findings were retrospectively collected and the microscopic features were also confirmed. The ratio of men to women was 26:24 and the ratio of mandible to maxilla was 28:26. In 12 of all, swelling with tenderness or mild pain were noted. The most common age group was from 16 to 25 years. Two lesions (3.7%) were early small lesions with a cyst like appearance. The calcification gradually increased with age: mottled in 14 (25.9%), orange peel in 3 (5.6%), and ground glass in 34 (63%). The characteristics of this disease were painless swelling, a ground glass appearance and thinning or fade down of cortical bone particularly the loss of the lamina dura in 40 lesions (74%) and the inferior border of the mandible in 20 lesions (71.4%). In the maxillary lesions, the maxillary sinus was partially involved in 7 (28.9%), and completly involved in 13 (50%). These maxillary lesions confined to only one site. In the mandibular lesions, there were 9 large lesions (32.1%), all of these crossed the symphysis. Mode of the expansions occurred in all directions in 31 lesions (57.4%), bucco-lingually in 13 (24.1%), and buccally in 7 (13%).     

Tomographic analysis of nasomaxillary and zygomaticomaxillary buttress bone thickness for the fixation of miniplates

The purpose of this study was to evaluate the bone thickness of the nasomaxillary and zygomaticomaxillary buttresses to identify the most favourable region for the installation of miniplates. Bilateral tomographic images of 103 individuals were evaluated, for a total of 206 nasomaxillary and zygomaticomaxillary buttresses. Measurements of bone thickness were performed in the parasagittal reconstructions along three vertical lines on the nasomaxillary buttress (21 measurement points) and four vertical lines on the zygomaticomaxillary buttress (28 measurement points). The vertical line measurements for each buttress were compared using the Kruskal–Wallis test. Spearman’s correlation coefficient was used to determine the correlation between the thicknesses obtained and patient sex and side (right/left). The level of significance adopted was 5%. The nasomaxillary and zygomaticomaxillary buttresses presented statistical differences in thickness at their respective points (P = 0.001). The analysis of the nasomaxillary buttress showed that the thicker bone for the installation of miniplates follows the long axis of the upper canine at a distance of 3 mm from the root apex. For the zygomaticomaxillary buttress, thicker bone to install miniplates was found distal to the distobuccal root of the first molar, at a distance of 3.5 mm from the limit of the infraorbital foramen.     

计算机导航技术在颌骨骨纤维异常增殖症手术中的应用

目的:探讨计算机导航技术在颌骨骨纤维异常增殖症手术中的应用价值.方法:纳入14例颌面部骨纤维异常增殖症患者,先将患者的术前CT数据导入计算机导航系统中,根据颌骨镜像原理进行术前设计及三维手术模拟,确定骨切除位置及范围.术中,根据病变部位及手术范围可将参考架置于患者前额或是下颌骨颏部.完成注册与配准,使手术视野和导航显示屏上的虚拟图像完全匹配.结果:面部的解剖结构与三维重建模型完全吻合,术中顺利完成实时导航.手术器械可实现空间定位,能够明确其与手术区域解剖结构的位置关系,手术具有高度的精确性与安全性.术后疗效的评估是通过术前计划和术后CT重建影像相融合得到的,1～3年的随访中没有发现并发症.结论:计算机导航系统在提高颌面部骨纤维异常增殖症的安全性与准确性方面具有较好的应用价值.     

Horseshoe Le Fort I osteotomy in combination with endosteal implants — a median-term follow-up study

Fourteen patients with Class VI resorption of the maxilla were treated with horseshoe Le Fort I osteotomy. In 11 cases, the procedure was followed by the placement of endosteal implants. In six patients, simultaneous placement of implants was carried out, while in five patients this was done in a second procedure. Ten patients wore their implant-supported dentures. In one patient, 5/8 implants were lost due to nonintegration. Three patients lost one implant each. The total number of implants placed was 76, and the survival rate of the implants was 88.1%. In the one-step procedure (n=42), the survival rate was 84.8%; in the two-step procedure (n=34), 92.3%. In comparison of the one-step to the two-step procedure, there was no statistically significant difference (P>0.11) between the amount of marginal peri-implant bone loss and the condition of the peri-implant soft tissues as measured 2 years after implantation.     

Hybrid fixation in the bilateral sagittal split osteotomy for lower jaw advancement

Miniplate and screw fixation has been widely used in bilateral sagittal splitosteotomy, but some issues remain unclear concerning its lack of rigidity whencompared to Spiessl''s bicortical technique. This paper demonstrates the hybridfixation technique in a case report. A 34-year-old female patient underwent a doublejaw surgery with counter-clockwise rotation of the mandible fixed using the hybridfixation technique. The patient evolved well in the postoperative period and is stillunder follow up after 14 months, reporting satisfaction with the results and nosignificant deviation from the treatment plan up to now. No damage to tooth roots wasdone, maxillomandibular range of motion was within normality and regression of theinferior alveolar nerve paresthesia was observed bilaterally. The hybrid mandibularfixation is clearly visible in the panoramic and cephalometric control radiographs.It seems that the hybrid fixation can sum the advantages of both monocortical andbicortical techniques in lower jaw advancement, increasing fixation stability withoutsignificant damage to the mandibular articulation and the inferior alveolar nerve. Astatistical investigation seems necessary to prove its efficacy.     

Comparison of stability of 2.0 mm standard and 2.0 mm locking miniplate/screws for the fixation of sagittal split ramus osteotomy on sheep mandibles

Ten unembalmed adult sheep mandibles were used. The mandibles were sectioned in the midline, followed by sagittal split ramus osteotomies to obtain 20 hemimandibles. Each distal segment was advanced 5 mm on each hemimandible. Ten of the specimens were fixed with 4-hole extended 2.0 mm titanium miniplates and screws and the other 10 were fixed with 4-hole extended 2.0 mm locking miniplates/screws. Each fixed specimen was mounted on a servo-hydraulic testing unit with the fixation device, and was tested to a range of forces of 0-140 N. The displacement values (mm) under 20, 60, 120, and 140 N were compared with the help of the Mann-Whitney U-test, and there were no significant differences between them at any force tested. Locking miniplate/screws and standard miniplate/screws showed similar displacement values at the range of forces tested.     

In vitro study of a modified sagittal split osteotomy fixation technique of the mandible: a mechanical test

This study was performed to evaluate the compressive mechanical strength of rigid internal fixation (RIF) using 1.5-mm L-shaped plates fixed with monocortical screws in sagittal split osteotomy (SSO). Thirty synthetic hemimandibles, which had all undergone a 5-mm advancement, were divided into three groups: three 12-mm bicortical titanium screws were placed in an inverted L pattern in group A; one straight 2.0-mm system spaced titanium plate fixed with four 5-mm monocortical screws was used in group B; two 1.5-mm system L-shaped titanium plates, each fixed with four 5-mm monocortical screws, were used in group C. The models were subjected to compressive and progressive mechanical tests with forces applied in the area between the second premolar and first molar to verify resistance in Newtons (N). A displacement speed of 1 mm/min was applied, with a maximum 10 mm displacement of the distal segment or until disruption of the fixation. The deformity and/or eventual rupture of the plates were evaluated, and consequently their technical stability was determined. The results showed that the modified fixation technique tested in this study on synthetic mandibles resulted in adequate stability and superior mechanical behaviour compared to simulated osteosynthesis with the use of a straight 2.0-mm titanium plate.     

Evaluation of fracture healing and subimplant bone response following fixation with a locking miniplate and screw system for mandibular angle fractures in a sheep model

This study aims to establish a mandible fracture model, and to review fracture healing following fixation with a locking miniplate system. Eighteen 2-year-old sheep were divided into three groups of six. Each animal had a single fracture that was anatomically reduced and internally fixed by a single 4-hole plate with two monocortical screws each side of the fracture. The fractures were internally fixed with poorly contoured conventional miniplates or poorly contoured mini-locking plate or well contoured conventional miniplates. Two sheep in each of the three groups were killed at 2, 4 and 8 weeks after surgery. The mandibles were radiographed then decalcified specimens were reviewed microscopically. No clinical difference was observed between the groups. All fractures were at an advanced stage of bony union by 4 weeks. Fracture union appeared radiographically more advanced with the locking plate system. This study established a protocol for simulating a fracture model for the study of fracture healing. A more advanced stage of union was seen for fractures internally fixed with locking plates/screws than with a conventional system. The observations suggest the purported biological benefits of locking miniplate system do exist.