下颌角骨折坚强内固定的生物力学分析

目的 比较下颌角骨折后两种不同的内固定方法对其应力分布的影响。方法 采用成人干燥无牙下颌骨,建立由咬肌、颞肌、翼内肌和翼外肌4组肌肉共同加载,由硅橡胶模拟颞下颌关节结构功能状态下的下颌骨机械力学模型。采用电阻应变片的测量方法,分析不同坚强内固定方式,即仅在下颌角上缘张力带固定一个小型接骨板和在下颌角下缘附加固定一个小型接骨板对下颌骨应力分布的影响。结果 两种固定方法下健侧的应力分布与骨折前均无显著性差异（P＞0.05）,但是仅在下颌角上缘固定一个小型接骨板将使患侧下颌骨下缘呈张应力趋势,造成应力轨迹的中断。结论 两种固定方法均可以恢复健侧的应力轨迹,但是要获得骨折区域充分的稳定性,固定两个小型接骨板是必要的     

髁突骨折解剖复位及小型接骨板坚强内固定

目的 探讨髁突骨折解剖复位和小型接骨板坚强内固定的技术要点和并发症的发生因素。方法 髁突骨折72例97侧（单侧47例,双侧25例）。陈旧性骨折12例,髁颈和髁颈下骨折81例,移位和脱位骨折90例。8侧未手术,7侧髁突摘除,6侧升支垂直截骨间接复位,76侧直接复位。59侧单板固定,21侧双板固定,2侧螺钉穿接固定,有22侧髁突呈游离再植,68例经颌后入路,21侧经耳屏前入路。术后1～3个月复查9例,3～6个月36例,6个月以上27例,复查内容包括骨折复位准确性、固定稳定性、骨折愈合改建,伤口愈合、面型、he关系、下颌运动、关节症状、神经损伤。结果 感染2侧,错he2例,假关节2侧,接骨板断裂3侧,接骨板变形2侧,骨折块再移位7侧,髁突吸收6侧,张口受限7例,关节疼痛5侧,关节杂音5侧,面神经损伤9例。并发症发生率33%（24/72例）,排除医源性因素后的并发症率14%（10/72例）。结论 切开复位及小型接骨板坚强内固定是治疗髁颈和髁颈下移位及脱位骨折的效方法,升支垂直截骨髁突游离再植是治疗髁突陈旧性骨折的可选择方法。低位髁颈和髁颈下骨折应采用颌后入路,接骨板应沿后外缘作张力带固定,髁颈下严重移位和陈旧性骨折需在髁颈前或乙状切迹处增加补偿固定。     

下颌骨骨折坚固内固定有限元分析

目的用三维有限元方法评价下颌骨骨折小型钛板坚固内固定稳定性，为下颌骨骨折坚固内固定提供生物力学的理论支持。方法建立下颌骨骨折的三维有限元模型，按照Champy的下颌骨骨折理想固定线进行小型钛板固定，分别模拟切牙咬合及健、患侧磨牙咬舍，得出骨折段的相对位移情况。结果下颌骨正中联合及下颌体骨折的坚固内固定，在功能咬合时，骨断端相对位移均在150μm内；下颌角骨折，切牙咬舍时，骨断端位移也在150μm内，但在健侧及患侧磨牙咬合情况下，骨断端位移较大。在同样的咬合力下，下颌体及下颌角处一块小夹板固定时，骨断端相对位移量不能保证骨折顺利愈合。结论两块小型钛板下颌骨正中联合或下颌体骨折坚固内固定，骨折段稳定，但在下颌角处并不能提供足够的稳定支持。下颌角和下颌体骨折一块小夹板张力带固定不够稳定，需选择合适的适应症及术后辅助固定或减小咬合力。     

下颌角骨折经口内坚固内固定临床研究

目的:探讨应用小钛板治疗下颌角骨折的临床可行性。方法:21例下颌角骨折或伴下颌体部骨折应用小钛板沿张力线作坚固内固定,复位技术及固定位置参照Champy方法,3个月～1年复查包括骨折复位准确性、固定稳定性、骨折愈合、伤口愈合、关系及神经损伤等。结果:21例下颌角骨折术后1例出现感染,4例术后出现干扰,其余咬合关系正常,X线复查未见骨愈合不良。结论:下颌角骨折经口内应用小钛板行张力带固定效果肯定,但不能完全摒弃颌间结扎。避免面部疤痕及面神经损伤,较传统的经颌下切口固定有明显的优点。     

非加压小型接骨板在下颌角骨折坚强内固定中的应用方式比较

摘要20世纪80年代后期,小型接骨板在下颌角骨折坚强内固定中的应用越来越广泛。小型接骨板一般分为加压型和非加压型两种,研究证明非加压型小型接骨板在下颌角骨折的固定中明显优于加压型接骨板。本文将就非加压型小型接骨板在下颌角骨折固定中的三种应用方式进行比较,结果表明两块小型板非加压情况下并行固定不仅稳固可靠,而且并发症最少。     

下颌角不利型骨折小型钛板内固定有限元分析

目的:用三维有限元方法评价下颌角不利型骨折小型钛板坚固内固定稳定性,为下颌角骨折坚固内固定提供生物力学的理论支持.方法:建立下颌角不利型骨折的三维有限元模型,按照下颌角小型钛板外斜线单块钛板固定及下方增加一块钛板固定,分别模拟切牙咬合及健、患侧磨牙咬合,得出骨折段的相对位移情况.结果:下颌角不利型骨折,切牙功能咬合时,骨断端位移在150μm内,但在健侧及患侧磨牙功能咬合情况下,骨断端位移较大.2块小钛板固定时,骨断端相对位移量较大,需要降低咬合力至80 N,1块钛板固定,骨断端相对位移量大,不能保证骨折顺利愈合.结论:下颌角不利型骨折2块小钛板固定稳定性不足,需要降低咬合力;1块小钛板张力带固定不够稳定,需要严格选择适应证.     

非加压小型接骨板在下颌角骨折坚强内固定中的应用方式比较

20世纪80年代后期，小型接骨板在下颌角骨折坚强内固定中的应用越来越广泛。小型接骨板一般分为加压型和非加压型两种，研究证明非加压型小型接骨板在下颌角骨折的固定中明显优于加压型接骨板。本文将就非加压型小型接骨板在下颌角骨折固定中的三种应用方式进行比较，结果表明两块小型板非加压情况下并行固定不仅稳固可靠，而且并发症最少。     

下颌骨颏部骨折小型接骨板固定的应变分析

目的探讨下颌骨颏部正中骨折内固定后功能状态下接骨板的应变情况。方法使用聚氨酯合成的下颌骨,建立由咬肌、颞肌、翼内肌、翼外肌和二腹肌5组肌肉共同加载的下颌骨机械力学模型。采用电阻应变片法分析前牙咬合（INC）,左侧磨牙咬合（L-MOL）,双侧后牙咬合（ICP）3种咬合状态下接骨板的应变。结果3种咬合状态下接骨板的外表面均表现为受压,且上缘接骨板的应变小于下缘接骨板。另外,加载时舌侧骨折线出现裂隙。结论下颌骨在功能状态下,颏部上下缘均受到张应力。颏部正中骨折,应该按照Champy的张力带理论固定2个接骨板。     

张力带单钛板固定结合支抗钉颌间牵引治疗下颌角骨折的临床研究

目的 :探讨联合采用小型钛板张力带固定,外加支抗钉辅助术后颌间牵引治疗下颌角骨折的临床疗效。方法 :下颌角骨折12例患者采用口内切口,单个小型钛板行张力带内固定;同时植入正畸支抗钉,术后行颌间结扎,从术后感染、咬合关系、张口度等方面分析疗效。结果:术后患者伤口均一期愈合,张口度恢复正常,咬合关系良好。仅1例合并糖尿病的患者,术后半年出现伤口裂开、钛板外露现象。结论 :单块小型钛板行张力带固定,辅助支抗钉术后颌间牵引治疗下颌角骨折是一种确实可行的方法。     

下颌骨骨折钛板内固定临床总结

作者通过自 1996～ 2 0 0 0年采用纯钛板对 2 0 0例下颌骨骨折内固定 ,在遵循解剖复位 ,坚强固定 ,无创外科 ,早期功能 4项原则下 ,降低了并发症 ,缩短了治疗期 ,早期恢复颌骨功能 ,现报道如下。1　材料与方法1.1　一般资料男性 170例 ,女性 30例 ,年龄 16～ 5 0岁。急诊开放性单纯下颌骨骨折 5 2例 ,闭合性单纯下颌骨骨折 6 0例 ,下颌骨伴复合伤 5 0例 ,陈旧性骨折 38例 ;垂直不利型骨折 6 0例 ,垂直有利型骨折 38例 ,水平不利型骨折 5 2例 ,水平有利型骨折 5 0例 ;单发骨折92例 ,多发骨折 86例 ,粉碎性骨折 2 2例 ;其中骨折固定术中拔牙 1…     

Biomechanical comparison of a new technique of mandibular angle fractures: biplanar and bicortical superior proximal 3 holes and bicortical inferior plate fixation

Miniplates have been used for mandibular angle fractures during the past 2 decades. The technique of placing single miniplate at the upper border based on the tension lines of the fracture was proposed by Michelet and Champy. The need for a second miniplate to be applied to the lower mandible has been discussed recently. Biomechanical comparison of biplanar and monoplanar dual-miniplate fixation techniques was investigated by Haug. Our hypothesis is in dual-miniplate fixation; the proximal 3 holes of superior border miniplate could be fixated by bicortical screws. The first 2 are at the proximal bone segment and are not related to the tooth and also superior to the alveolar nerve. Generally, the third molar tooth is extracted because it is at the fracture site. Hence, the proximal third hole could also be fixated by bicortical screws. We define a biplanar dual-miniplate technique in which the lower plate and the proximal 3 holes of the upper plate are fixated by bicortical screws. We have designed a study for biomechanical comparison of our method and popular types of mandibular fixation methods.     

不同程度老年人萎缩性无牙颌下颌骨骨折的内固定方式选择及相关生物力学分析

目的:比较3种不同程度萎缩性无牙颌下颌骨骨折的不同内固定方式及其效果。方法:构建不同程度的萎缩性无牙颌下颌骨体部骨折治疗模型,进行三维有限元分析,比较相同应力条件下骨折段位移的改变以及钛板的应力分布情况。结果:下颌骨Ⅲ度萎缩,采用1块2.0 mm 4孔钛板在下颌骨上缘进行固定,其骨折处移位较其余6种工况明显增大;相同萎缩程度的下颌骨,采用重建板固定比采用其他内固定方式骨折断端位移明显减少。Ⅲ度萎缩的下颌骨采用小型钛板固定,钛板所受应力分别接近及超过钛板的屈服极限。结论:对于Ⅰ度萎缩的无牙颌下颌骨骨折病例,下颌骨外侧双板固定以及下颌骨下缘重建板固定均能取得较为满意的固定稳定性,对于Ⅱ及Ⅲ度萎缩的无牙颌下颌骨骨折病例,下颌骨下缘重建板固定可以获得更好的固位稳定性。     

Management of mandibular angle fractures using the mandibular angle reduction forceps

The aim of this study was to determine whether or not the use of the mandibular angle reduction forceps decreases the incidence of post-operative complications. Forty-six patients, who presented with mandibular angle fractures with a displacement or dislocation, were randomly divided into two treatment groups. Both groups underwent an open reduction with a single upper border miniplate and screw fixation. For 23 patients, the mandibular angle reduction forceps was used to aid in fracture reduction, and for 23 patients, the reduction of the fracture was achieved using IMF. The post-reduction radiographs showed that the reduction forceps group had a higher proportion of precise anatomic alignment of fracture than those in the IMF group. In addition, the former group showed a lower rate of post-operative complications, as compared to the latter group. This study found that the use of the mandibular angle reduction forceps is an important factor for decreasing the incidence of post-surgical complication.     

Three-dimensional v/s standard titanium miniplate fixation in the management of mandibular fractures – A randomized clinical study

PurposeThe aim of this study was to compare treatment outcomes using three-dimensional and standard titanium miniplates in the management of mandibular fractures.Material and methodsA prospective study of 30 patients with mandibular fractures. Patients were randomly categorized into 2 groups with 15 patients in each group; patients in Group I were treated with 2.0 mm 3-dimensional titanium miniplate and screws and patients in Group II were treated with 2.0 mm standard plates and screws. Clinical parameters evaluated were: intra-operative assessment of reduction, intra-operative and post-operative assessment of stability of occlusion, mobility of fracture fragments and need for intermaxillary fixation. Radiographic parameters included pre-operative evaluation of displacement of fracture fragments and post-operative evaluation of bone union and plate fracture at different time intervals.ResultsIn Group I, 3 patients (20%) and in Group II, 8 patients (53%) had gap between fracture fragments during reduction. Six patients (40%) in Group I and 8 patients (53%) in Group II had mildly deranged occlusion on the 7th post-operative day. Two patients (13%) in Group I and 6 patients (40%) in Group II needed IMF till the end of the 1st month. No patients showed tissue dehiscence at the end of 1st and 3rd month post-operatively. Infection was not observed in any patient post-operatively. Five patients (33%) from Group I had displaced fracture fragments and 10 patients (67%) had severely displaced fracture fragments pre-operatively. Seven (47%) patients from Group II had displaced fracture fragments and 8 (53%) had severely displaced fracture fragments pre-operatively. Nine patients (60%) in Group I and 6 patients (40%) in Group II showed radiographic evidence of bone union after the 3rd month post-operatively.ConclusionThe use of 3D miniplate is a viable option for fixation of mandibular fractures routinely. 3D titanium miniplates showed comparable results compared to standard titanium miniplates.     

Further development of titanium miniplate fixation for mandibular fractures. Experience gained and questions raised from a prospective clinical pilot study with 2.0 mm fixation plates.

Miniplate systems are often used instead of more rigid systems for the treatment of mandibular fractures. While the most stable fixation method for all mandibular fractures is the 2.7 mm plate, most fracture sites and types are eminently suitable for miniplate fixation via an intraoral approach. However, the relatively low stability of the miniplate systems compared with rigid plate systems limits the indications for their use in mandibular fracture treatment, especially when immediate postoperative function is desired. A more rigid miniplate which provides increased stability was studied. The results of a preliminary study and a clinical trial of a 2.0 mm titanium miniplate system are presented in this paper. The therapeutic consequences of the lesser stability afforded by small plate systems are discussed. Indications for miniplate fixation without additional immobilization are reviewed.     

Outcomes of patients with teeth in the line of mandibular angle fractures treated with stable internal fixation.

PURPOSE: This study examines the relationship between postoperative infection and/or need for plate removal with the presence and management of teeth in the line of mandibular angle fractures. METHODS: Data were collected on patients treated by intraoral open reduction and internal fixation for fractures of the mandibular angle during an 8-year period. Outcome variables were postoperative infection and need for removal of the bone plate(s). The relationships of demographic variables, teeth in the line of fracture, and management of teeth in the line of fracture were analyzed using standard statistical methods. RESULTS: Four hundred two patients had sufficient follow-up for inclusion in the study. A tooth was present in the fracture line 85% of the time. Teeth in the fracture were removed in 75% of the fractures that contained teeth. Postoperative complications occurred in 19% of the sample. Fractures not containing teeth at the time of fracture had a 15.8% rate of postoperative infection compared with 19.1% for patients who had teeth in the fracture (P = NS). For angle fractures associated with a tooth, when the tooth was retained, the incidence of infection was 19.5%. When the tooth was removed, the incidence was 19.0% (P = NS). CONCLUSIONS: There is an increased risk for postoperative complications when a tooth is present, but the increase is not statistically significant. The incidence of postoperative infection and/or the need for plate removal is not affected by whether the tooth in the fracture is removed.     

Comparative analysis of the effectiveness of the mandibular angle fracture treatment methods

425 patients with mandibular angle fractures were treated at the Hospital of Kaunas University of Medicine (HKUM) Clinic of Maxillo-Facial Surgery. Treatment included the application of closed fracture fragments fixation methods (wire splint fixation, and Kirschner wire osteosynthesis), and methods of open fixation--osteosynthesis using the supra-periosteal miniplate, and osteosynthesis using supra-osseous Zes Pol plate (the latter method was modified by the authors). Relative computerized densitometry showed that closed fixation methods result in a faster healing of fractures. The findings of the pain threshold testing showed that open fixation methods more severely damage the function of the lower alveolar nerve. Using closed fixation methods, osteomyelitis occurred in 5.3% of cases, while using open fixation methods--in 15.3% of cases. Thus, the authors of the article maintain that when mandibular angle fractures, in the presence of suitable conditions, closed fracture fragments fixation methods should be given a priority.     

Miniplate osteosynthesis of fractures of the edentulous mandible

This study was performed to analyze treatment of fractures of the edentulous mandible and to discuss this method in relation to the mandibular height at the fracture site. Fifteen fracture sites in 11 patients with an edentulous mandible were retrospectively examined. These fractures were located: nine fractures in the mandibular body, three in the paramedian region, and three in the mandibular angle. Fractures in a mandible measuring more than 10 mm in the vertical height were treated with one miniplate. Fractures in an extremely atrophic mandible with 10 mm or less were treated using one or two miniplates, also using a modified Champy plate with 1.3 mm in thickness. A mandibular fracture with a height of 5 mm was treated with a combination of a microplate on the buccal side and a miniplate on the inferior border of the mandible with additional direct circumferential wiring. Oblique or splitting fractures were treated with direct circumferential wiring or a Herbert screw, at one fracture site each, respectively. Complications, including infection, fibrous union, nonunion and trismus, were not seen. In one patient, hypesthesia of the lower lip was, however, persistent 1 month after surgery. Miniplate osteosynthesis is the less invasive treatment, and it is suitable for fractures of the atrophic edentulous mandible, except for comminuted or defect fractures. To obtain stable fixation in severely atrophic mandibles, we need to consider the use of two miniplates or a combination with microplates.     

Analysis of complications in fractures of the mandibular angle--a study with finite element computation and evaluation of data of 277 patients.

AIM: The purpose of this study was to compute the load on different osteosynthesis plates in a simplified model using finite element analysis, and to find out whether miniplates were sufficiently stable for application at the mandibular angle. PATIENTS: Data from 277 patients with 293 fractures of the mandibular angle have been evaluated. METHODS: A computation model using finite elements was established in order to compute mechanical stress occurring in osteosynthesis plates used for fixation of fractures of the mandibular angle. In the second part of this study, the data from all in-patients treated for fracture of the mandibular angle were evaluated retrospectively. Age and sex of the patients, cause of fracture, state of dentition, type of therapy as well as complications were noted. RESULTS: In those tests, both the 1.0 mm miniplate and the 2.3 mm module plate were sufficiently stable. The rate of major complications (requiring revisional surgery with general anaesthesia) amounted to approximately 17% in comminuted fractures, or in non-compliant patients in which primary stability with a single miniplate did not appear sufficient, so that other osteosynthesis methods were used in addition. This rate was considerably higher than that in simple mandibular fractures. Simple fractures of the mandibular angle were just treated with one miniplate following Champy's guidelines strictly. In these fractures the rate of major complications was only 2.3%. CONCLUSION: In comminuted fractures and in non-compliant patients, the use of a stronger osteosynthesis material should be considered while in all other cases application of a single 1.0 mm miniplate was regarded as sufficient for fixation using open reduction.