多功能生物撞击机的应用与评估

目的 :应用新型多功能生物撞击机进行颌面部撞击伤与高速投射物伤的动物试验 ,评估该致伤系统 ,为颌面部创伤提供研究手段。方法 :使用生物撞击机的一、二级撞击系统对犬进行颌面部撞击伤与高速投射物伤的动物试验 ,应用信号测试记录系统通过微机对致伤过程中多路力学信号进行精确记录分析 ,实时测试致伤参数。结果 :一级撞击系统可造成犬颌面部软组织挫裂伤 ,颌骨骨折 ;二级撞击系统可造成犬颌面部软组织洞穿性缺损 ,颌面骨折、骨缺损。结论 :多功能生物撞击系统经过动物测试实验 ,性能稳定 ,可满足模拟颌面部撞击伤和投射物损伤的研究 ,具有良好的操作性和可重复性     

颌面部撞击伤伴发颅脑损伤的实验研究

目的 :研究颌面部撞击伤合并颅脑损伤的致伤机制和损伤特点。方法 :采用水平气动式撞击机分别以 4 77m/s± 0 5 3m/s(A组 )、9 16m/s± 0 6 5m/s(B组 )和 13 95m/s± 0 6 7m/s(C组 )的速度撞击兔左侧面中部 (n =6 )。观察致伤后动物的生命体征的变化 ,并对颌面部软组织、脑组织进行损伤的大体和光、电镜观察 ,测定致伤后 6h血清中脂质过氧化物 (LPO)、超氧化物歧化酶 (SOD) ,一氧化氮 (NO)的含量变化和脑含水量 ,同时记录致伤瞬间脑内压力和头颅冲击加速度。结果 :形态学改变低速和中速致伤组 (A和B组 )主要以局部损伤为主 ,高速致伤组 (C组 )则同时合并颅脑损伤。兔致伤后 6h血清中LPO、SOD值以及脑含水量C组显著高于A、B组 (P <0 0 5 ) ,而NO值明显低于A、B组 (P <0 0 5 )。头颅加速度和颅内压峰值C组均明显高于A、B两组 (P <0 0 5 )。结论 :致伤瞬间头颅冲击加速度响应和脑内压力变化是造成颌面部损伤合并颅脑损伤的重要生物力学因素     

下颌骨体部撞击伤和高速投射物伤的生物力学初步研究

目的:对下颌骨体部撞击伤和高速投射物伤进行生物力学初步研究.方法:采用水平气动式多功能生物撞击机,分别造成离体犬头下颌骨体部的撞击伤和高速投射物伤,测试致伤过程中的一些生物力学参数并进行分析.结果:撞击伤时下颌骨体部产生的冲击加速度远远大于高速投射物伤;冲击波作用于体表后,到达下颌骨表面的冲击波压力峰值迅速衰减,撞击伤衰减更为严重;撞击伤和高速投射物伤情况下,随着与伤区距离的增加,下颌骨的应变和应变率都呈迅速递减的变化规律,与相应部位牙齿和下牙槽神经血管束的损伤程度变化规律相符合.结论:下颌骨的应变和应变率是衡量邻近组织、器官间接损伤程度的重要生物力学指标,其中应变率较应变值更能反映出创伤程度.     

间接性颞下颌关节创伤动物模型的建立

目的 :建立一种新的颞下颌关节间接性创伤动物模型。方法 :采用新型多功能生物撞击装置 ,在 1 0MPa和 2 5MPa气压下以 0 .845kg圆柱形钢质抛射体对幼年山羊的颏部进行撞击 ,建立类似于儿童间接性TMJ损伤动物模型。结果 :颏部撞击可引起双侧TMJ的间接性损伤 ,包括关节积血、髁状突、关节盘以及关节附着和颞骨关节面等破坏性改变 ,撞击力越大对关节结构的损伤越重 ,这种破坏性改变与人类TMJ损伤后的表现相一致 ,病变较典型 ,致伤方法可靠。结论 :该模型适合于在实验室条件下进行TMJ损伤的研究 ,可用于TMJ损伤的基础理论及临床救治研究。     

口腔颌面部火器伤研究进展—火器伤模型与伤情判断

现代战争,由于武器的发展,高速小口径枪和小质量投射物的使用,使得现代火器伤与以往战争火器伤相比,在损伤机制、伤情判断和战伤救治上发生了变化。颌面火器伤在战伤中比较常见,其发生率随着武器的不断改进有增加的趋势。平时的火器伤多由于犯罪伤害引起。1　致伤模型1.1　枪伤模型早期的实验多采用常规的五四式手枪和匹配的制式子弹,手握式目测瞄准法直接射击实验动物,子弹的撞击速度一般小于400m/s,属于火器伤的低速撞击。由于实验稳定性差,现已较少采用;20世纪80年代开始,广泛应用“瑞典模型”,即采用五三式滑膛弹道枪,将其固定于可调式…     

间接性TMJ损伤的MRI表现及意义

目的:研究间接性颞下颌关节损伤的MRI表现及其在颞下颌关节病诊断中的意义. 方法:用多功能生物撞击机以10 Mpa的气压推动撞击杆,使0.845 kg的钢质圆柱形抛射体以(18.46±0.31) m/s的撞击速度在开口状态下撞击山羊颏部,撞击能量为139.2~148.8 J,间接造成幼年山羊双侧颞下颌关节的间接性损伤,分别于3 h、7 d、 2 周、1 月及3 月行MRI检查,采用斜矢状闭、开口位梯度回波T1W/3D/WATS、自旋回波PDW/TSE、T1W/SE和T2W/TSE序列及冠状闭口位T1W/3D/WATS、PDW/TSE扫描观察TMJ结构变化,并进行组织学观察. 结果:通过组织学观察可见间接性创伤可导致幼年山羊TMJ损伤,早期表现为髁突表面软骨碎裂,关节盘挫裂和移位,关节间隙减小及关节腔内有出血,损伤后期可见髁突表面软骨破坏,关节盘畸形,关节间隙减小.MRI可较清楚的显示上述改变.结论:间接性颞下颌关节损伤可导致幼年山羊TMJ软、硬组织结构和形态的变化,MRI能全面地观察TMJ损伤后组织改变,对颞下颌关节损伤的诊断有重要价值.     

颌面部高速投射物伤致下牙槽神经间接损伤的超微结构研究

目的：研究颌面部高速投射物伤导致的下牙槽神经间接损伤的特点。方法：18只实验犬随机均分为6组,以直径6．0mm、质量0．88g的高速投射物（不锈钢珠）致伤犬右下颌骨体部,但不直接伤及下牙槽神经;分别于伤后6h、24h、3d、7d、2w及4w处死实验犬,用透射电镜观察伤侧下牙槽神经距离弹着点0．5cm处、2．0cm处及对侧下牙槽神经的超微结构变化。结果：伤侧下牙槽神经距弹着点0．5cm处损伤较重,且超微结构变化出现较早;2．0cm处损伤相对较轻,且超微结构变化出现较迟;对侧下牙槽神经仅有轻度一过性损伤。结论：颌面部高速投射物伤导致的下牙槽神经间接损伤均有损伤范围较广,损伤程度随着距离的增加而迅速递减,损伤具有不均匀性等特点。     

犬颌面部致伤瞬间脑内压力变化研究

实验采用瑞典创伤模型方法建立动物模型。用重1.03g,射速800～850m/s和1350～1400m/s的钢珠致伤犬和离体犬头。造成重型颌面伤,记录致伤瞬间脑内压力变化,通过致伤射速和致伤点距颅脑的距离与脑内压力变化的关系研究颤面部高速投射伤伴发颅脑损伤的机理。实验结果证实,颌面部高速投射伤时瞬时空腔效应、冲击波效应造成的脑内压力变化是伴发颅脑损伤的重要原因。文中还对相关的临床意义进行了讨论。     

口腔颌面部高速投射物伤致牙周膜间接损伤的实验研究

目的：研究口腔颌面部高速投射物伤导致的牙周膜间接损伤的特点。方法：将18只实验犬随机分为6组,以直径6．0 mm、质量0．88 g的高速投射物致伤右下颌骨体部第四前磨牙根尖下方区域,但不直接伤及牙齿;分别于伤后6h、24h、3d、7d、2w及4w处死实验犬,观察右下颌第四前磨牙、第二前磨牙及左下颌第二前磨牙牙周膜的组织病理学表现。结果：右下颌第四前磨牙和第二前磨牙的牙周膜损伤较明显,但病理学变化可逆;左下颌第二前磨牙牙周膜仅见一过性血管扩张、充血。结论：口腔颌面部高速投射物伤可导致牙周膜发生间接损伤,病理学变化可逆;损伤程度随着牙齿与伤区距离的增加而递减。     

颌面部激光穴位麻醉的临床研究

材料与方法1.实验仪器:软波导CO_2激光麻醉器:(成都电讯工程学院研制)。主要特点为发射波长为10.6μm的远红外不可见光;输出功率5mw～5w连续可调;软波导传输灵活性0°～±90°;光斑直径2～3mm。     

兔颌面部撞击伤后血中有自由基反应和一氧化氮含量变化

目的探讨不同伤情颌面部撞击伤后机体自由基反应的改变及一氧化氮与损伤的关系。方法采用水平气动式撞击机分别以(4.77±0.53)m/s、(9.16±0.65)m/s和(13.95±0.67)m/s对兔左侧面中部进行撞击(n=6),建立不同伤情的动物模型,观察致伤后动物的生命体征的变化,并于伤后6h观察伤区软组织、伤侧视神经、视网膜、脑组织、脑干病理病变,测定血中脂质过氧化物(LPO)、超氧化物岐化酶(SOD)、一氧化氮(NO)含量,与正常组对照。结果伤后血中LPO、SOD含量明显升高,NO含量明显降低。结论颌面部撞击伤后,氧自由基及一氧化氮参与损伤反应,体内一氧化氮的生成受到抑制。     

Biomechanical changes in the head associated with penetrating injuries of the maxilla and mandible: an experimental investigation.

PURPOSE: In this experiment, we studied the craniocerebral injury that occurs due to the transmission of forces when maxillofacial gunshot wounds are sustained by the facial bones and cranium. MATERIALS AND METHODS: Forty fresh pigs' heads were wounded by one of the following methods: steel spheres weighing 1.03 g at an impact velocity of 1,400 m/s, steel spheres weighing 1.03 g at an impact velocity of 800 m/s, M193 military bullets, or M56 military bullets. Pressure waves in the brain, acceleration of the head, and stress changes in the facial bones and cranium at the moment of the impact were recorded by pressure and acceleration transducers and strain gauges and were statistically compared. RESULTS: Some obvious differences between the mechanical values obtained from high-and low-velocity missile wounds were found. A negative relationship between the peak value of the pressure wave in the brain and the distance from the point of impact to the transducer was obtained. The acceleration of the head in the direction of the ballistic path was the strongest in absolute value. There were differences in the stress values between the mandible and the temporal bone. CONCLUSIONS: Acceleration of the head, pressure wave changes in the brain, and injury from bony stress conduction all play important roles in associated craniocerebral damage after maxillofacial firearm wounds.     

Indirect testimony of stress conduction from mandible to skull in maxillofacial trauma: morphological changes of temporomandibular joint disc]

There were cerebral injuries accompanied in maxillofacial high velocity projectile wound.Owing to the special anatomic relationship between skull and facial bones,the stress conduction of bone was an important factor of cerebral injury in maxillofacial wound.In this experiment,the canine mandibular regions were wounded by steel spheres,which weight 1.03g,impacting velocity at 1400m/s,to produce severely maxillofacial firearm wounds.The morphological and pathological changes of temporomandibular joint disc of wounded side were observed with light and electron microscopes.The microscopic injuries of disc,including arrangement disorder of figre,spotty edema and some fibrous dissolution,etc,were found.These results have provided an indirect evidence of injurous mechanism of the cerebral injury accompaning maxillofacial high enery misslle wound.     

Small-vessel pathology and anastomosis following maxillofacial firearm wounds: an experimental study

This experiment was designed to provide a biological basis for early reconstruction of maxillofacial defects caused by firearms using free vascularized flap transfer. The pathologic changes of small-vessel injury, injury mechanism, and the feasibility for early anastomosis of these vessels in the maxillofacial region following high-velocity missile wounds were studied. Dogs' faces were wounded by a steel sphere, weighing 0.7 g and 1.03 g, with an initial velocity of 1,300 m/s or 1,500 m/s. Angiography and high-speed x-ray photography were used to record the effect of injury to blood vessels and other tissues. The pathologic changes in the small blood vessels in the wounds were studied by light microscopy (LM) and electron microscopy (EM). Anastomosis of small vessels in the wound was performed at different times after injury. There were temporary cavity effects and small vascular injury in the wounds. The pathologic changes of the small vessels included microthrombus formation, endothelial loss, breaks in the internal elastic layer, and necrosis. Degeneration of cells was found to end 3 cm from the wound edge. Anastomosis of the vessels performed 3 days after injury provided good short-term patency. These results suggest that the operation for repairing facial defects should be performed 3 days after injury.     

Orbital stress analysis--Part I: Simulation of orbital deformation following blunt injury by finite element analysis method.

PURPOSE: The purpose of this study was to develop a 3-dimensional finite element model (FEM) of the human orbit, housing the globe, to predict orbital deformation in subjects following a blunt injury. MATERIALS AND METHODS: A FEM of the human orbit including the eye, fatty tissues, and extraocular muscles was constructed. Simulations were performed with a computer using the finite element software NISA (EMRC, Troy, MI). The orbit was subjected to a blunt injury of a 0.5 kg missile with 30 m/s velocity. The FEM was then used to predict principal and shear stresses/strains at each node position. RESULTS: Two types of orbital deformation were predicted during different impact simulations: a) horizontal distortion and b) rotational distortion. Stress values ranged from 112.12 to 262.3 MPa for the maximum principal stress, from -226.8 to -552.1 MPa for the minimum principal stress, and from 111.3 to 343.3 MPa for the maximum shear stress. CONCLUSION: This is the first finite element study that demonstrates different and concurrent patterns of orbital deformation in subjects following a blunt injury. FEM is a powerful and invaluable tool to study the multifaceted phenomenon of orbital deformation.     

间接性TMJ损伤的生物力学初步研究

目的：研究间接性TMJ损伤时下颌骨不同部位在致伤过程中的生物力学改变情况。方法：采用颏部撞击法对6个新鲜羊头颅以4kg和10kg的压力推动0．845kg的圆柱形钢质抛射体进行撞击，对头颅加速度、双侧下颌骨体部、髁突颈部以及颞骨部的应变变化情况进行检测，应用新研制的生物撞击系统数据采集与分析软件对采集到的信号进行分析。结果：随撞击速度的增加，头颅加速度和各检测部位的应变也随之加大，髁突颈部可产生最大应变，颞骨部应变明显减小，说明颞颌关节的存在可减小颏部撞击伤对颅脑的损伤。在外力作用于颏部时，髁突颈部受到的应力最大，因而较其他部位容易发生骨折。当髁突颈部所受应力超出其自身生理范围时，即发生髁突骨折。结论：撞击速度和下颌骨内应力的变化是衡量下颌部损伤，特别是颞颌关节部损伤的重要生物力学参数。     

大鼠创伤性面瘫实验动物模型的建立

目的：建立大鼠面神经撞击伤的实验动物模型。方法：以不同速度和压缩幅度撞击２０只ＳＤ大鼠右侧面神经干,造成面神经不同程度瘫痪。结果：不同撞击条件可引起不同程度的面瘫,面瘫严重度与撞击速度和撞击压缩幅度成正相关关系,面神经干可出现散在纤维断裂、大部分神经纤维断裂、神经干完全断裂等病理改变。结论：所建立的大鼠创伤性面瘫动物模型操作简便,测速精确,致伤撞击力可控,且具有重复性,可引起不同程度的面瘫,其损伤病变与人类相似,病变典型,因此可做为研究创伤性面瘫的较理想的实验动物模型。     

一氧化氮在颌面部撞击伤中病理作用的实验研究

目的　探讨一氧化氮 (NO)在颌面部撞击伤中的作用及机制。方法　用撞击机以 4 77± 0 5 3,9.16± 0 6 5和 13 95± 0 6 7m/s撞击兔左侧面中部 (n =6 ) ,建立动物模型。伤后 6h观察伤区软组织、脑及脑干病理改变 ,测定软组织、脑与血中NO含量及脑含水量 ,与正常组对照。结果　伤后 6h血中NO含量明显降低 ,软组织和脑组织中NO含量及脑含水量均显著升高 (P <0 0 1)。结论　伤后血中NO生成受到抑制 ,但局部NO的生成与组织损伤程度一致 ,说明NO参与损伤过程 ,它可能是参与损伤的重要物质。     

Ten common myths of ballistic injuries

The science of ballistics can be confusing. Specific treatment dogmas regarding ballistic injuries should be examined to ensure that they are supported by scientific data. If determined to be unfounded, these dogmas should be discontinued from the teaching centers and eliminated from clinical practice. Tissue injury by ballistic projectiles is caused by the design and composition of a bullet and the velocity it is traveling when it strikes a target. Velocity or projectile shape alone cannot be the basis for any treatment. Each wound must be evaluated individually, with the determination of care decided by fact and clinical assessment, not rigid treatment protocols.