节点文献
创伤性泪道损伤有限元分析、影像解剖及手术治疗观察
The Finite Element Analysis and Imaging Anatomy and Treatment Research on Traumatic Lacrimal Passage Injury
【作者】 陈学华;
【导师】 谢民强;
【作者基本信息】 南方医科大学 , 耳鼻咽喉—头颈外科学, 2014, 博士
【摘要】 研究背景上颌骨骨折是颌面外科常见损伤,多复合其他部位创伤,如颅脑损伤,颧骨及鼻骨、眼眶等部位骨折,也可导致泪小管断离、泪囊窝和鼻泪管骨折,损伤泪道系统。国内周正炎报道颧上颌体复合骨折并发泪囊炎的比例约为33%。秦兴军报道为29.35%。国外报道上颌骨骨折并发泪囊炎的比例更高,Becelli等报道,面中部骨折合并泪道损伤高达46.5%。根据Uraloglu等的研究报告,骨性鼻泪管结构破坏的病例中,发现泪道阻塞病例高达68.4%,Osguthorpe等报告,鼻泪管外伤骨折在泪道疾病中占17%-21%。这类患者就诊时往往伴有全身其它脏器的损伤,而泪道损伤早期仅出现泪溢,不易引起医生重视,很多患者都是在全身病情稳定后出现了泪点溢脓,泪囊区肿痛等后期症状后才注意到泪道损伤的存在。而且,在泪道损伤早期作出准确诊断也并非易事,所以漏诊或延误诊断的病例不在少数。面中部骨折损伤后早期如出现溢泪,或后期出现内眦溢脓等症状,往往提示有泪道损伤的可能。诊断性泪囊冲洗是诊断泪道阻塞较简易的方法,泪道探通也可初步判定泪道的阻塞部位、程度、性质,但需掌握一定的操作技巧,否则有可能形成假道,而且也不能客观地将病变部位显示在图片上。近年来,不同的影像技术也可以用来诊断和评估泪道系统的改变:泪道碘油造影对泪囊大小及形态能很好显影,曾作为泪囊鼻腔吻合术前评价泪囊情况的首选检查。Hansen等报道泪小管阻塞时,其成功率为45.5%,而在非泪小管处,成功率为91.7%。为了便于术中定位,泪囊碘油造影前,可置不透光小金属片于中鼻甲前缘根部(中鼻甲腋)作标定物,根据所摄泪囊正、侧位X线片上标定物与泪囊的关系确定泪囊在鼻腔外侧壁的投影位置,但终因不能多平面立体显示泪道周围结构及阻塞,在指导临床治疗方面略显不足。泪道MR能清晰显示泪道引流系统的解剖位置、病变的形态及周围组织的关系,而且能从不同方向观察病变,有利于病变准确定位、诊断和鉴别诊断,并具有无创伤性的优点,而且可以在不接触放射线以及造影剂的情况下进行泪道系统管道的显示,但MR不能显示泪囊周围的骨性解剖结构以及稳定显示小的管道结构。CT在显示骨性解剖方面具有优势,能清晰显示泪囊窝的骨性解剖标志,但不易清晰显示微小且不在同一平面的泪道系统。近年来报道的泪道造影CT结合薄层CT扫描与泪道造影的优势,能清晰显示泪道系统及其与周围解剖的关系,扫描后在同步工作站进行多平面重建、曲面重建、三维重建等能从不同平面、不同角度对泪道系统进行立体显示,有利于泪道损伤的早期诊断及指导治疗。此法在慢性泪囊炎患者的诊断中已有见报道,应用于上颌骨骨折合并泪道损伤的诊断应更具价值,但鲜见报道。其意义在于可以同时显示上颌骨、泪道的骨折移位情况及泪道损伤阻塞情况,通过曲面重建可以对本不在同一平面的泪道系统在同一平面显示,加之造影剂的对比,可以直观显示泪道阻塞的部位与骨折的关系。用三维重建方法还可以较完整地显示出手术途径,各种结构的形态、位置和毗邻关系,并且可任意交换角度观察,供医生诊断参考,并可用于手术设计和模拟手术训练。对于慢性泪道阻塞目前有很多微创治疗方法,如泪道探通、激光治疗、高频泪道成形治疗、泪道支架或人工泪管等等。其中激光泪道再通术具有操作简便,组织损伤小,局部反应轻,创面愈合快,不破坏泪道正常结构,颜面不遗留瘢痕,尤其对于慢性泪囊炎、单纯性鼻泪管阻塞患者疗效较好,但有报道对于面中部骨折合并泪道损伤的治疗效果欠佳。鼻泪管逆行置管则具有手术操作简单、安全,手术无切口,不需造骨孔的特点,特别适用于年老体弱伴有高血压、糖尿病、出血倾向等全身疾病的患者,有报道其治愈率可达94%,与泪囊鼻腔吻合术相仿。但与传统慢性泪道阻塞的患者不同的是:在创伤性面中部骨折移位时,可能出现泪道系统的扭曲、骨折片嵌顿,导致以上这些方法都无法实施,有时只能选择泪囊鼻腔吻合术甚至泪囊摘除术。对于创伤性泪道损伤的治疗的大宗病例报道不多,而且也一直存在争议。有学者主张应早期进行治疗(如泪道冲洗、泪道探通、泪道置管等)可以防止以后可能出现的泪通狭窄、梗阻。国内秦兴军等回顾分析27例上颌骨骨折合并泪道损伤的临床资料,按治疗时间分两组。结果显示:10d以内组16例经治疗,15例泪道通畅,而10d以后组11例经治疗,5例泪道通畅,显示病程较短者疗效更好。但也有学者认为,创伤后早期出现的溢泪可能是由于局部的水肿压迫引起,不宜进行过多的干预治疗,认为相当一部分患者的泪道系统症状在经过一段时间的随访后可自行消失,只有症状持续3-6个月才考虑行鼻腔泪囊成形术。对于上颌骨骨折伴鼻泪管损伤患者治疗方式的选择可供借鉴的经验也不多,周振德等主张:病情较轻的可行泪道冲洗、泪道探通治疗,对泪道冲冼或探通失败者,多主张行泪囊鼻腔吻合术。段宗华等报告了24例上颌骨骨折合并泪道损伤的患者的治疗情况,随访半年治愈21例,好转1例,治疗方法包括药物治疗,冲洗泪道、泪道置管,泪小管吻合,鼻腔泪囊吻合术等。孔屹等对64例患者行泪囊鼻腔吻合术,61例术后效果良好,泪道冲洗通畅,4例复发患者接受了泪囊摘除术,其中之前15例曾于外院行泪道激光治疗,均未成功。在实施泪囊鼻腔吻合术时,上颌骨骨折合并泪道损伤的病例也比一般慢性泪道阻塞操作难度更大,由于泪囊窝骨折移位,泪囊偏移,可导致术中定位和显露泪囊更加困难,稍有不慎容易导致纸样板的损伤,眶内容溢出,影响操作并增加眶内感染的风险。综上所述,创伤性泪道损伤具有发病率高、早期确诊困难、治疗难度大的特点,且在治疗时机选择上也存在争议。基于这些原因,本文旨在对创伤性泪道损伤的发病机制、诊断方法、治疗方式及时机选择上从以下几个方面进行一定的探索:第一章(上颌骨创伤致泪道损伤有限元分析):基于正常成年人的DICOM格式CT数据,通过Mimics,Hypermesh和ABAQUS等软件快速建立颅上颌三维有限元模型。并在模型上模拟前颌鼻底、颧骨、鼻背意外着地撞伤的情形,观察上颌骨额突(泪道区域)、颧额缝、上颌窦前外侧壁等处的应力及位移情况,为上颌骨创伤泪道损伤的发生提供生物力学分析依据。结果发现,来源于上颌骨等其它部位创伤的应力传导,在上颌骨额突处都有较大的应力集中,加之此处骨连接紧密,骨质较薄,可能是骨折容易发生的原因。第二章(上颌骨泪囊窝CT解剖及其在泪囊鼻腔吻合中的意义):由于泪道损伤很多时侯需要选择行泪囊鼻腔吻合术,手术的关键是准确定位并显露泪囊,而常规的依中鼻甲腋定位开放泪囊的方法因此处骨质较厚,操作不便,特别是在泪囊窝骨折移位情况下定位开放泪囊窝更加困难,并发症增多。为了探索一种更为方便、有效而且微创的暴露泪囊的方法,本文通过80例鼻窦薄层CT扫描的影像资料,对经鼻泪囊鼻腔吻合术相关泪囊窝应用解剖进一步研究。分析钩突与泪骨、泪囊窝的影像解剖关系,发现泪囊窝前上部骨质较厚,后下部骨质菲薄。而且在泪囊窝下部,钩突往往位于泪囊窝后方,往上逐渐靠前,于中部连接于泪骨或上颌骨额突,上部连接于中鼻甲外侧或眶纸板上。从而提出从泪囊窝下端、钩突前方泪骨入路显露打开泪囊窝行泪囊鼻腔吻术的手术入路,为鼻内镜下泪囊鼻腔吻合术提供解剖学指导。第三章(创伤性泪道损伤的泪道造影CT重建与手术治疗观察):鉴于目前对创伤性泪道损伤治疗方式与治疗时机的文献报道不足,而且存在保守治疗与手术治疗之间的争议,本文回顾性分析我院28例创伤性泪道损伤患者泪道造影CT资料及手术方式、术后疗效等资料,以探讨创伤性泪道损伤治疗方式与时机的选择。在泪道造影薄层CT扫描的基础上进行多平面重建、泪道曲面重建、最大密度投影、三维重建等,以评价泪道造影CT重建技术对创伤性泪道损伤的诊断价值。在手术方式选择上,提出泪道减压用于泪囊、鼻泪管骨折引起泪道压迫阻塞患者的早期治疗,可为泪小管置管、鼻泪管置管等微创治疗创造条件,有助于创伤性泪道损伤的早期治疗与康复,对于延期治疗的患者行鼻内镜下鼻腔泪囊吻合术,在术中进一步验证前文所述经泪囊窝后下部泪骨入路于钩突前方开放泪囊窝的可行性。并进行一年以上随访观察,评估治疗效果以探讨手术时机的选择。第一章上颌骨创伤致泪道损伤有限元分析目的:在临床上我们碰到的创伤性泪道损伤的病例中,来源于交通意外的占多数。常因鼻背、颧弓、前颌鼻底等突出位置着地,导致鼻背的粉碎性骨折、颧额缝、颧弓及上颌窦前外侧壁等处的骨折。泪道区域并非创伤的直接受力位置,可能是来源于上颌骨其它部位创伤的应力传导,加之此处骨连接紧密,骨质较薄,所以骨折容易发生。本文基于DICOM格式CT数据,利用Mimics软件,对上颌骨骨性结构进行三维重建,建立数字虚拟模型,进而建立上颌骨创伤泪道骨折有限元模型,为上颌骨创伤泪道骨折提供生物力学分析依据。方法:1.研究对象:健康男性志愿者一名,25岁,身高168cm,体重60kg。2.设备:Philips/Brilliance64排螺旋CT一台,联想ThinkPad X230i笔记本电脑一台,软件环境:Mimics10.01, Hypermesh和ABAQUS3.CT扫描参数设定及扫描方法:采用Phillip64排螺旋CT进行横断面数据采集。扫描参数为:140kV,250mAs,准直器宽度(collimation)64mm×0.625mm,螺距(pitch)0.5,重建层厚(width)0.8mm,旋转扫描时间0.33s。扫描范围均从头顶至下颌,扫描时间约2-4s。获得层厚0.8mm的横断面图像。4.有限元分析方法:将多排螺旋CT扫描图像的DICOM数据导入Mimics10.1(比利时,Materialise公司),对模型进行修饰,去除一些无意义的杂点,减少噪声,建立上颌骨三维表面模型,然后以STL三角面片格式导出网格,输入至hypermesh前处理软件。由三角面片网格生成四面体网格。最后,将网格导入到有限元软件ABAQUS中进行有限元计算。假定材料力学特性为非均质、连续和各向同性的弹性材料。设定皮质骨的弹性模量为13.7GPa,泊松比为0.3;松质骨的弹性模量为1.37GPa,泊松比为0.3;牙齿的弹性模量为18.6GPa,泊松比为0.31。求解方法:将所研究的弹性物体离散为有限个单元,选择单元位移函数建立单元刚度矩阵以及整体刚度矩阵,引入边界条件和求解方程式,获得所有节点的位移分量,由节点位移求出各单元应力。整个过程由计算机自动完成。边界条件:在枕骨大孔周围作全方位的固定约束。模拟创伤撞击数值模拟的加载:前颌鼻底加载节点数为40,每个节点分配的力为20N。力的峰值为800N,上升时间为2ms,下降时间为6ms。颧骨处加载节点数为50。每个节点分配的力为20N,力的峰值为1000N。上升时间为2ms,下降时间为6ms。鼻背处加载节点数为30,每个节点分配的力为30N,力的峰值为900N,上升时间为2ms,下降时间为6ms。5.分析项目:应用Mimics、Hypermesh和ABAQUS等软件快速建立上颌骨复合体三维有限元模型,并评价该方法的可行性,在模型上模拟鼻背、颧骨、前颌鼻底着地撞伤,观察上颌骨额突(泪道区域)、颧额缝、上颌窦前外侧壁等部位的应力及位移情况。结果:1.获得了正常上颌骨CT扫描断层影像和数据并通过建立Mimics软件建立上颌骨三维三角面片模型,重现了上颌骨的几何外形,能够得到上颌骨及泪囊区直观的整体印象(图1-1)。2.将Mimics软件得到的三角面片模型,导入到hypermesh中。生成三维实体网格。最后得到模型共1209357个节点和283701个四面体单元(图1-2)。3.当前颌鼻底受撞击时,应力向上颌骨额突、上颌窦前外侧壁、颧弓等处传导,在加载2ms时应力主要集中在鼻周,在加载6ms时,可在鼻泪管区域(上颌骨额突)、颧弓、上颌窦前外侧壁等处测得较大应力及位移(图1-3-图1-7)。在撞击应力传导过程中,上颌骨额突、颧额缝及上颌窦前外侧壁的应力与时间曲线,见图1-16。上颌骨额突区最大应力为4.03653MPa,出现在0.0052s。颧额缝区域最大应力为1.8744MPa,出现在0.0056s。上颌窦前外侧区域最大应力为3.33138MPa,出现在0.0056s。最大应力:上颌骨额突>上颌窦前外侧壁>颧额缝。4.当颧骨处受撞击时,应力也向颧额缝、上颌骨额突及上颌窦前壁、后壁传导。在2ms时最大位移主要在同侧颧额缝、上颌骨额突及上颌窦前壁、后壁,在8ms时主要集中在上额窦前后壁并传至对侧(图1-8-图1-11)。在撞击应力传导过程中,上颌骨额突、颧额缝及上颌窦前外侧壁的应力与时间曲线,见图1-17。上颌骨额突区域最大mises应力为6.37585MPa,出现在0.0068s。颧额缝区域最大应力为4.1071MPa,出现在0.0072s。上颌窦前外侧区域最大mises应力为3.34868MPa,出现在0.0048s。各区域在mises应力达到峰值前都经历一个不小的回落,然后重新上升达到峰值。最大应力:上颌骨额突>颧额缝>上颌窦前外侧壁。5.当鼻背处撞击时,应力沿鼻骨、上颌骨额突向周边对称传导。2ms时主要在鼻背、眶内壁有较大应力,8ms时波及梨状孔周围及眶外侧壁。2ms时最大位移集中在鼻骨、眶内壁及上颌骨额突区域,8ms时扩大至眶下壁、上颌窦前外侧壁(图1-12-图1-15)。在撞击应力传导过程中,上颌骨额突、颧额缝及上颌窦前外侧壁的应力与时间曲线,见图1-18。上颌骨额突最大应力为4.65828MPa,出现在0.0076s。颧额缝区域最大应力为1.87941MPa,出现在0.0064s。上颌窦前外侧区域最大mises应力为1.82245MPa,出现在0.004s。各区域在mises应力达到峰值前也经历一定的回落,然后重新上升达到峰值。最大应力:上颌骨额突>颧额缝>上颌窦前外侧壁。结论:1.基于CT扫描数据,利用Mimics、Hypermesh和ABAQUS等软件建立了上颌骨三维有限元模型,这种方法可行、有效,建模速度较快。并可在模型上进行模拟创伤环境,分析其应力传导情况,为上颌骨泪道损伤提供力学依据。2.通过模型模拟交通意外时鼻背、颧骨、前颌鼻底等突出位置着地,都可观察记录到在上颌骨额突区域产生较集中的应力而且产生一定的位移,加之此处骨连接紧密,骨质较薄,可能是泪囊窝、鼻泪管区域容易骨折的力学原因。第二章:泪囊窝CT影像解剖及其在泪囊鼻腔吻合术中的意义目的:由于泪道损伤很多时侯需要选择行泪囊鼻腔吻合术,手术的关键是准确定位并显露泪囊,而常规的依中鼻甲腋定位开放泪囊的方法因此处骨质较厚,操作不便,特别是在泪囊窝骨折移位情况下定位开放泪囊窝更加困难,并发症增多。为了探索一种更为方便、有效而且微创的暴露泪囊的方法,本文通过80例鼻窦薄层CT扫描的影像资料,对经鼻泪囊鼻腔吻合术相关泪囊窝应用解剖进一步研究。分析钩突与泪骨、泪囊窝的影像解剖关系,提出从泪囊窝下端、钩突前方泪骨入路显露打开泪囊窝行泪囊鼻腔吻合术的解剖依据,为鼻内镜下泪囊鼻腔吻合术提供解剖学指导。方法:1.临床资料:80例成年患者,慢性鼻炎65例,伴鼻中隔偏曲15例(排除鼻息肉,钩突变异,外伤等情况),男女各半,年龄18-55岁,平均年龄(35.28±11.77)岁,行鼻窦轴位薄层CT扫描。2.所需材料:(1)CT扫描仪:Philips Brilliance64层螺旋CT,(2)图像后处理软件:系统自带Extended brilliance workspace工作站,(3)16侧鼻腔矢状位锯开之头颅标本,来源于南方医科大学解剖教研室,(4)手术小圆刀片,尖刀片,电钻,骨剪,骨凿及鼻内镜器械,(5)游标卡尺等测量工具。3.CT扫描参数设定及扫描方法:采用Phillip64排螺旋CT进行横断面数据采集。患者取仰卧位,头部正位不偏斜,以保证扫描图像双侧对称,扫描范围为眶上缘至硬腭,扫描参数140KV、250mAs,准直器为16×0.625mm,螺距0.75,重建矩阵512×512,扫描视野350cm,扫描时间约2-4s。获得层厚0.8mm的横断面图像。重建层厚为lmm(连续重建),所有重建数据均传送至Extended brilliance workspace工作站进行多平面重建。4.后期处理:在同步工作站(Extended brilliance workspace V4.5)对泪骨、泪囊窝等结构进行多平面重建显示,调整轴线以最佳显示双侧骨性泪道。在轴位图像上测量双侧泪囊窝深度(即泪前嵴至泪后嵴的直线距离),在冠状位图像上测量双侧泪囊窝长度(即泪囊窝顶至底的距离),以上数据分别测量两次,取平均数。5.尸头标本模拟经鼻内镜下泪囊鼻腔吻合手术方法:鼻内镜下以中鼻甲前端附着处(中鼻甲腋)为中心,钩突前缘为后界作约1.5cm×1.0cm的蒂在上的U形黏膜瓣,分离黏膜瓣。一般可清晰显示泪额缝,前方为上颌骨额突,后方为泪骨,用头部直径为2mm的反向咬骨钳打开泪囊窝下部、钩突前方的泪骨,此处骨质菲薄,易于打开,然后于钩突前方向上向前适当扩大至暴露整个泪囊。造口大小与泪囊大小相仿。经下泪点插入泪道探针至泪囊,于泪囊前方切开泪囊,模拟手术过程中测量泪囊前上部及后下部的骨质厚度。6.分析项目:对80例患者CT资料进行测量分析,了解泪骨、钩突、中鼻甲腋与泪囊窝的关系,测量泪囊窝的长度与深度;观察在尸头标本上模拟经鼻泪囊鼻腔吻合术的可行性,测量泪囊窝前上部及后下部骨质的厚度。7.统计分析:应用SPSS13.0软件对数据进行统计分析。泪囊窝前上部及后下部骨质厚度以均值±标准差(x±s)表示,样本均数比较采用配对样本的t检验,以P<0.05为有统计学意义。结果:1.80例鼻窦薄层CT测量结果显示:泪囊窝的长度为(12.210±2.030)mm,深度为(6.359±1.222)mm,性别比较无差别,提示在行鼻内镜下泪囊鼻腔吻合术时如需完全显露泪囊,则骨窗大小应与之相符;钩突与泪囊窝的解剖关系见(表2-1)。在泪囊窝下部,钩突往往位于泪囊窝后方,往上逐渐靠前,于中部连接于泪骨或上颌骨额突,上部连接于中鼻甲外侧或眶纸板上。在泪囊窝下部,钩突62.5%附于泪囊窝后方的眶纸板,31.2%附于泪囊窝,6.3%附于上颌骨额突;在泪囊窝中部(中鼻甲腋平面),钩突55.0%附于眶纸板,30.0%附于泪囊窝,10.0%附于上颌骨额突,5.0%附于中鼻甲外侧;在泪囊窝上部,钩突47.5%附于眶纸板,25.0%附于泪囊窝,12.5%附于上颌骨额突,15.0%附于中鼻甲外侧(见图2-1)。为鼻内镜下行泪囊鼻腔吻合术时,在泪囊窝下端钩突前方入路开放泪囊窝提供应用解剖依据2.16个尸头标本均在鼻内镜下从钩突中下部前方泪骨入路显露并打开泪囊窝完成泪囊鼻腔吻合术,无眶纸板损伤(图2-2)。泪囊窝前上部及后下部骨质的厚度为(2.962±0.330)mm,(0.021±0.005)mm(t=35.33,P<0.05),提示泪囊窝前上部骨质厚度明显大于后下部,行鼻内镜下泪囊鼻腔开放术时宜从后下部打开显露泪囊,然后往上扩大,方便操作,且有利于减少黏膜损伤。结论:1.泪囊窝前上部大部分对应为上颌骨额突,骨质较厚,泪囊窝后下部大部分对应为泪骨,骨质菲薄,行泪囊鼻腔开放时先开放泪囊窝后下部相对较易。2.在泪囊窝下部,钩突往往位于泪囊窝后部,往上逐渐靠前,于中部连接于泪骨或上颌骨额突,上部连接于中鼻甲外侧或眶纸板上。从泪囊下部钩突前方的泪骨入路打开泪囊窝,继而向上扩大行泪囊鼻腔吻合,大多有足够空间于钩突前方开放泪囊,从而保留钩突及黏膜,减少创伤。准确认识钩突与泪骨、泪囊窝的解剖关系,有助于鼻内镜下行泪囊鼻腔开放时定位、暴露泪囊,避免手术并发症。第三章创伤性泪道损伤的泪道造影CT重建与手术治疗观察目的:创伤性鼻筛眶区骨折容易损伤泪道,表现为溢泪、溢脓。目前对于创伤性泪道损伤的治疗大宗报道不多,而且存在争议。有学者主张早期应进行泪管置管以防止以后可能出现的泪道狭窄、梗阻,也有学者认为,创伤后早期出现的溢泪可能是由于局部的水肿压迫引起,不宜进行置管等干预治疗,理由是泪道置管本身也会对泪道黏膜造成损伤,从而引起日后的泪道粘连狭窄。而且部分患者在泪囊窝、上颌骨额突发生骨折移位情况下,泪道探通、激光泪道成形,泪道置管等眼科治疗慢性泪道阻塞的常规手段无法实施,往往需要选择创伤性更大的泪囊鼻腔吻合术。但无论选择何种治疗方法,准确评价泪道压迫阻塞的部位及其与周围骨质的关系都是十分必要的,对治疗起关键指导作用。本文对28例创伤性泪道损伤的泪道造影CT检查资料及泪道减压、置管、鼻内镜下泪囊鼻腔吻合术等治疗情况进行回顾性分析,以评价泪道造影CT重建技术对创伤性泪道损伤的诊断价值,探索创伤性泪道损伤的治疗方法与治疗时机。同时观察前文所述经泪囊窝后下部泪骨入路于钩突前方开放泪囊窝行鼻内镜下泪囊鼻腔吻合术的可行性。方法:1材料与方法1.1研究对象:2007年2月至2012年10月,我院眼科及耳鼻咽喉科收治的外伤性面中部骨折患者28例,男20例,女8例,年龄18-55岁,平均年龄(38.45±5.27)岁,左侧18例,右侧10例。病程ld-4w19例,4w-24w9例。诊断标准:面部外伤骨折后出现泪溢、泪小点溢脓、冲洗泪道不通畅或鼻腔内无液体流出等不同症状,泪道探通时因泪囊受压无法探及泪囊下部及鼻泪管,CT泪囊造影+重建显示泪囊窝或骨性鼻泪管骨折受压,既往无泪道病史。即诊断为面中部骨折合并泪道损伤。患者分组:病程1d-4w为:小于4周组;病程4w-24w为:大于4周组。1.2设备:(1)CT扫描仪:Philips Brilliance64层螺旋CT(2)图像后处理软件:系统自带Extended Brilliance Workspace工作站,(3)奥林巴斯鼻内镜手术系统,枪状镊,鼻中隔剥离子,黏膜刀,小圆刀,反向咬骨钳,黏膜切钳,鼻中隔吸引头,骨凿。(4)眼科泪道探针及手术器械,(5)一次性泪道冲洗针,(6)造影剂:欧乃派克300mgI/ml,利多卡因,的卡因,肾上腺素等,(7)泪小管义管:Φ=0.64mm广州市博视医疗保健研究所,(8)鼻泪管义管:管外径2.5mm,球外径4.2mm,广州市博视医疗保健研究所。1.3CT扫描参数设定及扫描方法:造影前、后采用Phillip64排螺旋CT进行横断面数据采集。扫描参数为:120kV,200mAs,准直器宽度(collimation)64mm×0.625mm,螺距(pitch)0.5,重建层厚(width)0.8mm,旋转扫描时间0.33s。平扫后于患侧泪道注射对比剂2m1(欧乃派克300mgI/ml)。方向为从头侧到足侧,仰卧位,扫描范围均从眶上缘至硬腭,扫描时间约2-4s。获得层厚0.8mm的横断面图像。1.4后期处理:在同步工作站(Extended brilliance workspace V4.5)对泪囊及鼻泪管进行容积成像(Volume rendering, VR)、最大密度投影(Maximum intensity projection,MIP)、曲面重建(Curved plane reconstruction, CPR)、三维重建(Three-dimensional reconstruction,3-d R)。图3-1-图3-7。1.5手术方法:患者取仰卧位,局麻或插管全麻下手术,1%丁卡因20ml加0.1%肾上腺素4ml混合液鼻腔表面麻醉、收缩鼻腔。先行闭合性鼻骨、上颌骨额突复位,复位后根据阻塞部位予泪小管置管或鼻泪管置管,仍有骨质压迫无法置管者予鼻内镜下去除压迫泪道骨质(泪道减压)再行泪道冲洗或置管,由于泪道骨折严重,仍不通畅且无法置管者行泪囊鼻腔吻合术。(1)泪道减压:鼻内镜下以中鼻甲前端附着处(中鼻甲腋)为中心,钩突前缘为后界作约1.5cm×1.0cm的蒂在上的U形黏膜瓣,分离黏膜瓣。一般可清晰显示泪额缝或骨折的泪骨,去除压迫泪道的骨折片,然后用直径为2mm的反向咬骨钳沿上颌骨额突后缘向上、向下适当扩大,不要去除太多骨质,最关键是将压迫泪囊或鼻泪管的骨质去除。经下泪点插入泪道探针至泪囊,如可以较轻松地进入鼻泪管,冲洗泪道通畅后恢复黏膜瓣。然后根据阻塞部位分别予泪小管置管或鼻泪管置管术。(2)泪小管置管:8号送线针自上泪小点穿入通过泪囊、鼻泪管,从鼻泪管口伸出,将1号丝线从鼻泪管拉入上泪点,于上泪点处通过丝线将泪小管义管拉入泪小管从鼻泪管引出,同法将泪小管义管的另一端从下泪小点拉入泪道也从鼻泪管口引出,义管的上下泪小点之间用显微剪开一小孔,注意勿使其断成两根。鼻腔端义管两端予打结固定。如泪小管断裂需找到泪小管两个断端行泪小管显微缝合,术后抗生素眼药水点眼1周。(3)鼻泪管置管方法:暴露泪囊后用泪小点扩张器扩大术眼上泪小点,8号送线针自上泪小点穿入通过泪囊、鼻泪管,从鼻泪管口伸出。剪断线上端,钩线针伸入鼻腔将线勾出,同时退出送线针。线的鼻侧断端系上球头硅胶管,向上拉至鼻泪管及泪囊区,并将管置于其中,冲洗上下泪小管通畅。术后处理同上。(4)泪囊鼻腔吻合术:鼻内镜下以中鼻甲前端附着处(中鼻甲腋)为中心,钩突前缘为后界作约1.5cm×1.0cm的蒂在上的U形黏膜瓣,向上分离至中鼻甲腋上方约0.8cm,下约至钩突中点前方。分离黏膜瓣,一般可清晰显示泪额缝,泪骨位于其后,用头部直径为2m的反向咬骨钳打开钩突下端前方的泪骨,此处骨质菲薄,易于打开,然后于钩突前方向上向前适当扩大至暴露整个泪囊。造口大小与泪囊大小相仿。造成约1.2cm×1.0cm大小骨窗,暴露泪囊,呈“]”形切开左侧泪囊(右侧呈“[”形切开),泪囊瓣与钩突端鼻黏膜缝合,或用银夹钳夹固定,明胶海绵填塞术腔。术后处理同前,见图3-9。1.6疗效判定:治愈:6个月后流泪症状消失,冲洗泪道通畅;有效:6个月后流泪减轻,冲洗泪道欠通畅;无效:仍流泪,指压泪囊区有分泌物从泪点返流,冲洗泪道不通。1.7观察项目:1.7.1在同步工作站进行MPR、MIP、CPR、VR、3-d R,显示泪囊的形态,泪囊窝骨折移位情况及泪道阻塞部位,在MPR矢状位或冠状位图像上调整轴线的位置、重建平面尽量与中鼻甲腋-泪囊连线平行,测量中鼻甲腋至泪囊顶、泪囊底之间的距离。1.7.2经泪囊窝后下部泪骨入路于钩突前方开放泪囊窝行鼻内镜下泪囊鼻腔吻合术的可行性。1.7.3观察两组患者治疗有效率(痊愈数+有效数/总数)的差异。1.8统计学分析:应用SPSS13.0软件对数据进行统计分析。中鼻甲腋至泪囊顶、泪囊底之间的距离以均值±标准差(x±s)表示,样本均数比较采用配对样本的t检验,以P<0.05为有统计学意义。计数资料用百分率表示;治疗有效率的比较采用四格表资料的fisher确切概率法,以P<0.05为有统计学意义。结果1.囊造影CT扫描结合MPR、MIP、CPR.VR、3-d R等后处理,发现:泪小管堵塞6例,泪囊阻塞14例,鼻泪管阻塞8例。2.轴位CT可良好显示泪囊、鼻泪管的骨折移位;冠状位重建在显示眶纸板、鼻中隔、上颌骨额突左右方向上的移位有优势(但一般不能在同一层面显示泪囊和鼻泪管);矢状位重建能很好显示鼻骨、上颌突额突的塌陷移位以及鼻泪管前后方向上的骨折压迫;通过曲面重建能清晰在同一平面上清晰显示泪囊、鼻泪管等泪道引流系统;通过最大密度投影、三维重建能直观显示泪道骨折及阻塞、狭窄等情况,将泪道骨折压迫情况显示在同一张平片上(图3-1-图3-6),中鼻甲腋至泪囊顶、泪囊底之间的距离分别为6.679±0.859mm、4.943±0.628mm(t=12.312,P=0.000),中鼻甲腋至泪囊顶的距离大于其至泪囊底的距离,差距有统计意义,提示在行鼻内镜下泪囊鼻腔开放时,需向上扩大至超过中鼻甲腋一倍以上距离才能完全显露泪囊。3.在面中部骨折合并泪道损伤患者泪囊鼻腔吻合术中,经泪囊窝后下部泪骨入路于钩突前方开放泪囊,过程顺利,容易暴露泪囊,手术时间55.6±10.5min,无眶纸板损伤等情况出现。4.根据病情不同,行单纯泪道减压4例,泪小管置管6例,鼻泪管置管10例,泪囊鼻腔吻合8例。治疗结果:痊愈18眼(64.29%),好转5眼(17.86%),无效5例(17.85%)。其中,1d-4w组有效率为94.73%(18/19);4w-24w组有效率为55.56%(5/9),两者差异有统计意义(p<0.05)。说明小于4周组预后好于大于4周组。见表3-1。结论:1.泪囊造影CT扫描对面中部骨折合并泪道损伤患者具有较高的诊断价值。2.中鼻甲腋的位置介于泪囊顶、泪囊底之间中部偏下,行经鼻内镜下泪囊鼻腔吻合术时宜从泪囊窝后下部开始打开泪骨,往上扩大至中鼻甲腋上方1倍距离,可以方便完全显露泪囊。3.泪道减压是临床治疗面中部骨折合并泪道损伤的有益途径,为泪道骨折移位压迫泪道情况下行泪小管置管、鼻泪管置管等微创治疗创造条件,有助于创伤性泪道损伤的早期治疗与康复;4.在面中部骨折合并泪道损伤患者泪囊鼻腔吻合术中,经泪囊窝后下部泪骨入路于钩突前方开放泪囊,是简便、安全、行之有效的暴露泪囊的方法,特别适用于泪道骨折移位情况下定位、寻找泪囊。5.损伤后早期行泪道减压、泪小管置管、鼻泪管置管等微创手术治疗效果较好,超过1个月后治疗效果较差。全文小结:1.基于CT扫描数据,利用Mimics、Hypermesh和ABAQUS等软件建立了上颌骨三维有限元模型,这种方法可行、有效,建模速度较快。通过模型模拟交通意外时鼻背、颧弓、前颌鼻底等突出位置着地,都可记录到在上颌骨额突区域产生较集中的应力而且产生一定的位移,而且应力峰值大于颧额缝及上颌窦前外侧壁,加之此处骨连接紧密,骨质较薄,可能是泪囊窝、鼻泪管区域容易骨折的力学原因。2.泪囊窝前上部大部分对应为上颌骨额突,骨质较厚,泪囊窝后下部大部分对应为泪骨,骨质菲薄。在泪囊窝下部,钩突往往位于泪囊窝后部,往上逐渐靠前,于中部连接于泪骨或上颌骨额突,上部连接于中鼻甲外侧或眶纸板上。从泪囊下部钩突前方的泪骨入路打开泪囊窝相对较易,继而向上扩大行泪囊鼻腔吻合,大多有足够空间于钩突前方开放泪囊,从而保留钩突及黏膜,减少创伤。此法特别适用于泪道骨折移位情况下定位、寻找泪囊。3.中鼻甲腋的位置介于泪囊顶、泪囊底之间中部偏下,行经鼻泪囊鼻腔吻合术时宜从泪囊窝后下部开始打开泪骨,往上扩大至中鼻甲腋上方1倍距离,可以方便完全显露泪囊。4.泪囊造影CT结合多平面重建、最大密度投影、曲面重建、三维重建等能清晰显示泪囊形态、泪囊窝骨折移位情况、泪道阻塞部位以及钩突与泪囊窝的关系,为鼻内镜下泪囊鼻腔吻合术提供指导。5.泪道减压是临床治疗面中部骨折合并泪道损伤的有效方法,为泪道骨折移位压迫泪道情况下行泪小管置管、鼻泪管置管等微创治疗创造条件,有助于创伤性泪道损伤的早期治疗与康复;损伤后早期行泪道减压、泪小管置管、鼻泪管置管等微创手术治疗效果较好,超过1个月后治疗效果差。
【Abstract】 Research backgroundMaxillary bone fracture, a common injury in recent years, is often associated with trauma of other parts of the body, such as traumatic brain injuries, zygomatic arch, nasal bone and orbit fracture, and the mid-facial fracture which can lead to lacrimal path damage. According to statistics, about25-30%of patients with traumatic mid-face fractures were combined with lacrimal path damage, especially the Le Fort Ⅱ type fractures because of the fracture line crossing the frontal process of the maxillary bone, making canaliculi, lacrimal sac and nasolacrimal duct injuries common occurrences. The rate of lacrimal passage injury was as high as46.5%in the cases of fracture of nasal ethmoidal orbital area. Clinically, it was characterized by epiphora or pyorrhea. More frequently, these patients received initial treatments in the emergency department, so the lacrimal path injury characterized by epiphora was often ignored because the presence of the severe trauma such as concussion, skull base fracture. The diagnosis of lacrimal path damage is often delayed one or more weeks later after the injury. Moreover, difficulties in early, accurate diagnosis of lacrimal passage damage results in not a few misdiagnosis or delayed diagnosis cases. Therefore, if cases report ephiphora, we need to consider the possiblitiy of lacrimal passage damage. Signs of Epiphora are often associated with lacrimal passage damage. Lacrimal passage syringing and lacrimal duct probing are simple methods to detect the possible existence of lacrimal passage damage and preliminarily determine its site, extent and character, but they cannot display the situation on image. The lacrimal sac lipiodolography, which offers a precise size and shape of the lacrimal sac and often regarded as the first choice to evaluate the lacrimal passage before dacryocystorhinostomy (DCR), cannot display the anatomy surroundings. MR can show the anatomy of the lacrimal drainage system and the anatomy surroundings of the lacrimal sac more clearly, but cannot display the bony anatomy and small pipeline structure stably. Despite their merits, the methods mentioned above cannot display the lacrimal passage obstruction and the bony anatomy surrounding the lacrimal passage clearly on the same image simultaneously. CT scan has the advantages to display bony anatomy clearly, but cannot display the tiny lacrimal drainage system clearly on the same plane, whereas the lacrimal radioquaphy can display the lacrimal drainage system clearly. A combination of lacrimal radiography and CT scan, computed tomographic dacryocystography (CTDCG) has the advantages to display the tiny lacrimal drainage system and the bony anatomy clearly and simultaneously, thus enabling more accurate detection of lacrimal duct obstruction or the fracture of the lacrimal fossa(FS). Through the multiplanar reconstruction (MPR), curve planar reformation (CPR, maximum intensity projection (MIP) and three-dimensional reconstruction (3-d R),we can see the anatomic relationship more accurately from different directions to help making treatment decisions. This method applied in the diagnosis of patients with chronic dacryocystitis was reported, and it should be more valuable to assess the lacrimal passage injury caused by mid-face fractures, but rarely seen reported. Though the application of this method has been reported previously in the diagnosis of patients with chronic dacryocystitis, its role in assessing the lacrimal passage injury caused by mid-face fractures may be more valuable and thus needs to be accessed.The treatment experience of large cases of traumatic lacrimal passage damage ihasrarely been reported and remains controversial. Some scholars advocate early treatment to prevent lacrimal passage stricture and obstruction, while other scholars caution against undue intervention because the causes of epiphora may be simply local edema or oppression early after trauma and few lessons can be drawn from existing literature on treating traumatic lacrimal passage injury. Various methods exist for the treatment of chronic dacryocystitis, such as lacrimal passage probing, lacrimal passage irrigation, lacrimal laser therapy, high-frequency lacrimal forming treatment, lacrimal stent or artificial lacrimal intubation etc. However, the traumatic lacrimal passage injury is more clinically challenging because of the distortion of the lacrimal passage or the incarcerated displaced bone segments due to the fractures of frontal process of maxilla or the lacrimal bone. Dacryocystectomy (DCR) may be only selected at some cases. Endoscopic surgery, originated in the late1980s, with the advantages of better curative effect, minimally invasive and faster recovery, has been the general consensus of otolaryngology practitioners and got ophthalmologist’s approval. As one of the contemporary advanced technologies of nasal sector, it increasingly becomes a replacement to traditional lacrimal sac surgery. Zhou Bing (1994) reported for the first time in China that his clinical success rate reached91.5%in35cases of endoscopic dacryocystorhinostomy and the deflection of nasal septum and inferior turbinate hypertrophy can be easily healed with endoscopic which can lead to epiphora. Currently, this method is often used in the treatment of lacrimal duct injury caused by mid-face fractures. However, due to distortion or incarceration of the lacrimal passage in some traumatic lacrimal passage injury, it is more difficult to locate and expose the lacrimal sac when performing endoscopic dacryocystorhinostomy, and more easily to break the orbital lamina and increase the risks of orbital infection.Based on the characteristics and difficulties of the above diagnosis and treatment for traumatic lacrimal passage injury, this dissertation attempts to ascertain the diagnosis and treatment techniques from the following aspects:The first chapter:clinically, incidents of traumatic lacrimal passage injuries are often found primarily in traffic accident victims. The impact force of the prominent position such as nasal dorsum, base of nose and zygoma to the ground lead to fractures of the lacrimal bone and frontal process of maxillary bone, and hurt the lacrimal passage. The lacrimal fossa is not the immediate force location of trauma, the hurt force is derived from the force on the prominent position such as nasal dorsum,base of nose and zygoma, et al. But the bone of lacrimal passage area, thin and connected closely, is vulnerable to fracture and the lacrimal passage gets hurt indirectly.In order to simulate the occurrence of traumatic lacrimal passage injury, we established a digital virtual model using Mimics based on DICOM format CT data of a normal adult and observed the internal structure from different aspects. We transferred the model into Hypermesh and ABAQUS (finite element software), and established the finite element model of a skull-face bone. By simulating the situation of the impact force of the prominent position such as nasal dorsum, base of nose and zygoma to the ground, we ascertained the internal stress and displacement of the lacrimal passage, frontozygomatic suture and anterior-lateral wall of the maxillary sinus and provided the biomechanics basis for the traumatic lacrimal passage injury.The second chapter:DCR is a main method to treat the traumatic lacrimal passage injury. The key procedure of DCR is to locate and expose the lacrimal sac accurately. But it is very difficult to expose the lacrimal sac through the ordinary method by drilling open the front process of the maxillary bone, since the front process of the maxillary bone is very thick and prone to fracture shift. Meanwhile, it is easy to break the orbital lamina and make the orbital fat pop out, thus increasing the risk of orbital infection. We further explored the applied anatomy of DCR to look for a better procedure to expose the lacrimal sac. We found that the uncinate process (UP) is more frequently posterior to the lower part of the lacrimal fossa and the thickness of the low part of the lacrimal fossa is thinner than the upper part. Thus we proposed a lacrimal bone access anterior to the low part of the unciform process for lacrimal sac exposure in DCR and observed its feasibility. We found that this is a convenient, effective and minimally invasive method which can retain UP and mucous membrane and reduce trauma.The third chapter:28cases of traumatic lacrimal passage injury were retrospectively reviewed. Multiplanar reconstruction (MPR), curve planar reformation (CPR), maximum intensity projection (MIP) were performed and three-dimensional reconstruction (3-d R) on the extended brilliance workspace was done based on the CT scan data to observe the its value in the diagnosis and treatment.We found that lacrimal intubation, laser treatment and other minimally invasive treatment were infeasible because of the distortion or incarceration of the lacrimal passage. For the delayed cases, we performed DCR through the lacrimal bone access anterior to the lower part of the unciform process for lacrimal sac exposure(discussed in the second chapter), and observe its effectiveness. We proposed to decompress the lacrimal passage under endoscope after reduction of nasal bone and the front process of the maxillary bone. It can create conditions for minimally invasive treatment such as lacrimal intubation and laser treatment and assists in early evaluation of the feasibility.Chapter1The finite element analysis of lacrimal passage injuryObjective:IN order to simulate the occurrence of traumatic lacrimal passage injury, we established a digital virtual model using Mimics based on DICOM format CT data of a normal adult. We can observe the internal structure from different aspects.We transferred the model into Hypermesh and ABAQUS (finite element software), and established the finite element model of a skull-face bone. By simulating the situation of the impact force of the prominent position such as nasal dorsum, base of nose and zygoma to the ground, we can observe the internal stress and displacement of the lacrimal passage, frontozygomatic suture and anterior-lateral wall of the maxillary sinus, thus providing the biomechanics basis of the traumatic lacrimal passage injury.Method:1. Research object:A healthy male volunteer,25years old, height168cm, weight60kg. 2. Apparatus:(1) CT scanner:Philips Brilliance64spiral CT scanner(2) Lenovo ThinkPad X230i laptop(3) Software environment that Mimics10.01, Hypermesh and ABAQUS3. CT scanning parameter setting and scanning method:The subjects were in supine position, with median sagittal plane perpendicular to bed surface. The scanning range was from head to chin. Scanning conditions were as follows:tube voltage:140kV, tube current:250mAs, collimation:64mm x0.625mm, pitch0.5mm, width0.8mm, tube rotating period per cycle:0.33s.4. The finite element analysis:Construction of digital three-dimensional finite element model of maxillary complex:importing the scanned data of DICOM format into Mimics10.01software, by threshold segmentation automatically or manually, reconstructing the three-dimensional structure of maxillary complex, then exporting the data with point cloud format and reimporting into Hypermesh, assisted by grid processing and surface generation to form geometric models and reconfigure them, followed by importing the data into finite element analysis softwares (ABAQUS) and making impact text.5. Analysis items:To observe the feasibility of construction of three dimensional finite element model of craniofacial bone based on CT scanning DICOM formation data through Mimics, Hypermesh and ABAQUS.To observe the stress distribution and displacement around the lacrimal passage area, frontozygomatic suture and the anterior-lateral wall of maxillary sinus after indirect impact from the prominent positions such as nasal dorsum, zygomatic bone and nasal floor.Results:Based on CT scann data of craniofacial bone, a three dimensional finite element model including1209357nodes and283701units was established. The complicated shape of mid-face was duplicated, the macroscopic impressions on maxillary, zygomatic bone, maxillary sinus and orbital cavity was obtained(Fig.1-1, Fig.1-2).Given impact from the nasal floor, we saw stress contribution spreading to the frontal process of the maxillary bone, the anterolateral wall of the maxillary sinus, zygomatic arch, etc. The stress concentration was around the nose at2ms. Major stress concentration and displacement was seen around the frontal process of the maxillary bone, zygomatic arch and the anterolateral wall of the maxillary sinus (Fig.1-3~Fig.1-7). The greatest mises stress:the frontal process of the maxillary bone> the anterolateral wall of the maxillary sinus> frontozygomatic suture (Fig.1-16).Given impact from zygomatic bone, we saw stress contribution spreading to the frontozygomatic suture, the frontal process of the maxillary bone, the anterior wall and postier wall of the maxillary sinus, etc. The stress concentration was around the above areas at2ms, and was around the anterior wall and postier wall of the maxillary sinus, spreading to the other side at8ms (Fig.1-8~Fig.1-11). The stress contribution experienced a certain fall before reaching the stress peak. The greatest mises stress: the frontal process of the maxillary bone> the frontozygomatic suture> the anterolateral wall of the maxillary sinus (Fig.1-17).Given impact from the nasal dorsum, we saw stress contribution spreading along the nasal bone and the frontal process of the maxillary bone to ambitus evenly. The stress concentration was around the nasal dorsum and the inner wall of the orbit at2ms, and was around the piriform aperture and the lateral wall of orbit at8ms. The great displacement was around the nasal bone, the inner wall of the orbit and the frontal process of the maxillary bone, and spreading to the inferior wall of orbit, anteriorlaterior wall of the maxillary sinus at8ms (Fig.1-12~Fig.1-15). The stress contribution also experienced a certain fall before reached the stress peak. The greatest mises stress:the frontal process of the maxillary bone> the frontozygomatic suture> the anterolateral wall of the maxillary sinus (Fig.1-18).Conclusions:The application of Software Mimics, Hypermesh and ABAQUS in the construction of finite element model of maxillary complex is feasible and effective. This application can simulate traumatic environment on the model and provide the biomechanical basis for traumatic lacrimal passage injury.Through the model we can simulate the situation of traffic accident(the prominent position such as nasal dorsum, zygomatic bone and nasal floor impacting on the ground), bigger stress conduction can be observed around the frontal process of the maxillary bone (lacrimal passage area), where the bone, thin and connected closely, is prone to fracture.Chapter2Lacrimal fossa CT imaging anatomy and its value in dacryocystorhinostomyObjective:To explore the relationship between the uncinate process and the lacrimal fossa, we proposed a lacrimal bone access anterior to the uncinate process at the low part of the lacrimal fossa for lacrimal sac exposure in dacryocystorhinostomy, to provide operative guidance for the endoscopic dacryocystorhinostomy.Method:1. Research object:64-slice spiral CT data of80cases collected from October2011to December2013in our hospital, including chronic rhinitis65cases, deviation of nasal septum15cases, excluded nasal polyps, uncinate process malformation. Gender:40male,40female. Age:18to55years old, average (35.28±11.77) years.2. Apparatus:(1) CT scanner:Philips Brilliance64spiral CT scanner(2) Image post-processing workstation:Extended Brilliance Workspace(3)16cases of specimen from anatomy teaching and research section(4) surgery small round blade, knife, drill, bone shears, bone chisel and nasal endoscopic instrument(5) measuring tools such as vernier caliper3. CT scanning parameter setting and scanning method: The subjects were in supine position, with median sagittal plane perpendicular to bed surface. The scanning range was from the upper margin of the orbit to hard palate. Scanning conditions were as follows:tube voltage:140kV, tube current:250mAs, collimation:64mm×0.625mm, pitch0.5mm, width0.8mm, tube rotating period per cycle:0.33s.4. Post-processing:Multiplanar reconstruction was performed under extended brilliance workspace V4.5. The depth of lacrimal fossa (the straight distance from anterior lacrimal crest to the posterior lacrimal crest) was measured on the axis image, the length of lacrimal fossa (the straight distance from the lacrimal sac fossa top to bottom) was measured on the coronary image, Each measuring was undertaken twice and the results were then averaged.5. Simulate the endoscopic dacryocystorhinostomy on specimens:A u-shaped mucosal flap in front of the UP about1.5cm x1.0cm hinged superiorly as the centre of the operculum of the middle turbinate (OMT) was made to expose the frontal process of the maxillary bone and the lacrimal bone(LB). The junction between the maxillary and the lacrimal bone(MB-LB) was easy to identify. The LB was first nibbled away inferiorly then upward to expose the entire lacrimal sac. A lacrimal probe was inserted to the lacrimal sac through the lower lacrimal puncta and the lacrimal sac was cut open in the front. The thickness of inner walls of anterosuperior and posteroinferior part of lacrimal fossa was measured.6. Analysis Items:The anatomical relationship of the lacrimal fossa (FS) to the operculum of the middle turbinate (OMT), lacrimal bone (LB) and uncinate process (UP) were observed.The depth of lacrimal fossa (the straight distance from anterior lacrimal crest to the posterior lacrimal crest) was measured on the axis image, the length of lacrimal fossa (the straight distance from the lacrimal sac fossa top to bottom) was measured on the coronary image. The thickness of inner walls of anterosuperior and posteroinferior part of lacrimal fossa was measured during DCR.7. Statistical analysis:The data were analyzed using SPSS13.0, the data about the thickness of inner walls of anterosuperior and posteroinferior part of lacrimal fossa being recorded with the mean±standard deviation (x±s). Paired samples t test was administered, with P <0.05for statistical significance.Results:The length of lacrimal fossa (FS) was (12.210±2.030)mm, the depth of the lacrimal fossa was (6.359±1.222)mm. No gender difference was found in samples. The bone window size should be consistent with it to fully expose the lacrimal sac during DCR. The anatomical relationship of the lacrimal fossa (FS) to the uncinate process (UP):At the lower level, the UP was adjacent to the orbital lamina(62.5%), lacrimal fossa(31.2%)and the frontal process of maxillary bone(6.3%); at the middle level, the UP was adjacent to the orbital lamina(55.0%), lacrimal fossa(30.0%), the frontal process of maxillary bone(10.0%) and lateral wall of the middle turbinate(5.0%); at the upper level, the UP was adjacent to the orbital lamina(47.5%), lacrimal fossa(25.0%), the frontal process of maxillary bone(12.5%) and lateral wall of the middle turbinate(15.0%). It provided surgery guidance for a lacrimal bone access anterior to the lower part of the unciform process for lacrimal sac exposure in DCR.Dacryocystorhinostomy was performed on16specimen through lacrimal bone access anterior to the lower part of the unciform process for lacrimal sac exposure, causing no orbital lamina damage. The bony thickness of the anterosuperior part of lacrimal fossa (FS) was (2.962±0.330)mm, while the bony thickness of the posteroinferior part was (0.021±0.005)mm (t=35.33, P<0.05). It suggested that the thickness of the lower part of the lacrimal fossa is thinner than the upper part. It was convenient, effective and minimally invasive to take a lacrimal bone access anterior to the low part of the unciform process for lacrimal sac exposure in DCR which could retain UP, mucous membrane and reduce trauma. Conclusions:The anterosuperior part of the lacrimal sac fossa corresponding to the frontal processes of the maxillary bone is thicker than the posteroinferior part corresponding to lacrimal bone. It is easy to knot open the lacrimal bone first posteroinferior when performing DCR.The uncinate process was more frequently posterior to the lacrimal fossa at the lower level, then adjacent to lacrimal bone or the frontal process of maxillary bone at the intermediate level, last adjacent to the lateral middle turbinate or orbital lamina at the upper level. When performing dacryocystorhinostomy, we should first nibble the LB away inferiorly then superiorly to the lacrimal sac top above the OMT, allowing enough space to expose the lacrimal sac in front of the UP, which retains UP and mucous membrane and reduce trauma. Accurate reproduction of the anatomic relationship of UP and lacrimal fossa helps to improve the efficacy of surgery and avoid complications.Chapter3Computed tomographic dacryocystography and endoscopic surgery to traumatic lacrimal passage injuryObjective:To explore the diagnosis, treatment methods and opportunity in lacrimal passage injury combined with mid-face fractures, and evaluate the diagnostic utility of computed tomographic dacryocystography (CTDCG) to provide operative guidance for the endoscopic DCR. To observe the feasibility for lacrimal sac exposure in dacryocystorhinostomy by lacrimal bone access anterior to the lower part of the unciform process.Method:1. Research object:28cases with lacrimal passage injury combined with mid-face fractures hospitalized in our hospital from February2007to October2012were reviewed.20males and8females. The age range is from18to55years, average being (38.45±5.27) years. Diagnostic criteria:The patients were diagnosed as below:epiphora or pyorrhea associated with mid-facial fracture caused by trauma, blockage of lacrimal pathway or no liquid flow in the nasal cavity after the flush of the canaliculus lacrimalis. The bottom of the lacrimal sac or the lacrimonasal duct was unreachable in the probing of lacrimal passage due to compression of lacrimal sac or lacrimonasal duct. Compression of the lacrimal sac or the nasolacrimal duct by fracture chips was displayed by Multi-slice spiral CT dacryocystography with3-d R. No history of epiphora.Patient group:Less than4weeks group:disease course from1day to4weeks;More than4weeks group:disease course from4weeks to24weeks.2. Apparatus:(1) CT scanner:Philips Brilliance64spiral CT scanner(2) Image post-processing workstation:Extended Brilliance Workspace(3) the Olympus nasal endoscopic surgery system, nasal gun-shaped forceps, nasal septum stripping, mucosal knife, small circular knife, reverse rongeur, mucous membrane cutting pliers, bone chisel, et al.(4) the lacrimal passage probe and surgical instruments(5) eye syringing needle(5ml)(6) contrast agent:Ominipaque solution (300mg/ml)(7) canaliculi silicone tube(8) lacrimonasal duct silicone tube.3. CT scanning parameter setting and scanning method:The patients were in supine position, with median sagittal plane perpendicular to bed surface, underwent CT scan before and after dacryocystography. The scanning range was from the upper margin of the orbit to hard palate. Scanning conditions were as follows:tube voltage:140kV, tube current:250mAs, collimation:64mm×0.625mm, pitch0.5mm, width0.8mm, tube rotating period per cycle:0.33s.4. Post-processing: The following reconstruction techniques after scanning including curved plane reconstruction (CPR), maximum intensity projection(MIP) and three-dimensional reconstruction (3-d R) were processed on an extended brilliance workspace V4.5. The distance between the top and bottom of dacryocyst to the opercule of the middle turbinate (OMT) was measured.5. Operation methods:Under general anesthesia or regional anesthesia, the patients first received closed nasal bone and maxilla frontal process fracture reduction under endoscope, then received canaliculus intubation or lacrimonasal intubation according to the block site. If intubation was not possible due to the compression of the fractures, lacrimal passage decompression was needed. After decompression, canaliculus intubation or lacrimonasal intubation was attempted again. If intubation was still not possible, dacryocystorhinostomy was recommended.(1) Canaliculus intubation procedures:a8#wire feeding needle was passed from superior lacrimal punctum through lacrimal sac and lacrimonasal duct to inferior nasal meatus. Through the inferior meatus, guided by the8#wire feeding needle, a artificial tube was implanted from lacrimonasal duct into canaliculus, out of the superior lacrimal punctum, then from the low lacrimal punctum, through the lacrimal sac and lacrimonasal duct to inferior nasal meatus by the same way. Knot the two ends in the nasal meatus in order to fix the artificial tube. Patients receive a topical antibiotic drop of tobramycin0.3%and dexamethasone0.1%(Tobradex, Alcon, Fort Worth,U.S.A.)4times a day for7days.(2) nasolacrimal duct intubation procedures:a8#wire feeding needle was passed from superior lacrimal punctum, through lacrimal sac and lacrimonasal duct, to inferior nasal meatus. Through the inferior meatus, guided by the8#wire feeding needle, a lacrimonasal duct silicone tube was implanted from inferior meatus into lacrimal sac. The post-surgery treatment was the same as mentioned in (1).(3)Lacrimal passage decompression procedures:The nasal mucosa was decongested with oxymetazoline spray. The lateral wall of the nose was infiltrated with local anesthetic (2%lidocaine with1:100,000epinephrine). Soaked neurosurgery pledgets with phenylephrine0.25%and lidocaine3%were used as a vasoconstrictor of the nasal mucosa. Under nasal endoscope a u-shaped mucosal flap was made in front of the UP about1.5cm×1.0cm hinged superiorly as the centre of the operculum of the middle turbinate (OMT) to expose the frontal process of the maxillary bone and the lacrimal bone(LB). Generally the fractured lacrimal bone was easy to be identify. Fractures with displaced bone segments were removed. Then the canaliculus was syringed, then the mucosal flap was restored, followed by gelatin sponge packing. The post-surgery treatment was the same as mentioned in (1).(4) dacryocystorhinostomy procedures:Under nasal endoscope, a u-shaped mucosal flap was made in front of the UP about1.5cm×1.0cm hinged superiorly as the centre of the operculum of the middle turbinate (OMT) to expose the frontal process of the maxillary bone and the lacrimal bone(LB). Generally the fractured lacrimal bone was easy to be identify. The fractures with displaced bone segments and part of the frontal process of the maxillary bone was removed. The LB was nibbled away inferiorly then superiorly to reach the lacrimal sac top above the OMT. The lacrimal sac was opened vertically with the crescent blade as "]"shape on the left side ("[" shape on the right side), creation of posteriorly hinged lacrimal sac and nasal mucosal flaps with silver clip clamps (the posteriorly hinged lacrimal sac was anastomosed to nasal mucosal flaps with silver clip clamps, with gelatin sponge filling the cavity. The post-surgery treatment was the same as mentioned in (1). All patients were subsequently followed up for6to12months.6. Determination of the curative effects:Cure:no epiphora with patent lacrimal passage6months after treatment; irrigation test shows the lacrimal passage is patent;Effective:occasional epiphora with limited patency of lacrimal passage6months after treatment;Ineffective:epiphora not improved.7. Analysis Items:The morphology of dacryocyst was observed and the location of fracture and lacrimal passage obstruction were determined. The distance between the top and bottom of dacryocyst to the OMT was measured. The feasibility of lacrimal bone access anterior to the lower part of the unciform process for lacrimal sac exposure in DCR was observed.The curative effects of the two groups were observed.8. Statistical analysis:The data were analyzed using SPSS13.0.The data about the distance between the top and bottom of dacryocyst to the OMT were recorded with the mean±standard deviation (x±s), followed by paired samples t test, with P<0.05for statistical significance. The data about the curative effects were recorded with percentage, followed by the administration of Fisher’s Exact Test (four table data), with P<0.05for statistical significance.Results:1. The displacement fracture of the lacrimal fossa and block site of the lacrimal passage could be displayed clearly by CTDCG with MPR, MIP, VR and3-d R.6cases of canaliculus obstruction,14cases of lacrimal sac obstruction,8cases of lacrimonasal duct obstruction were showed (Fig.3-1-Fig.3-6).2. The distance between the top and bottom of dacryocyst to the OMT were6.679±0.859mm,4.943±0.628mm (t=12.312, P=0.000) respectively. The former was greater than the latter. The OMT was located a little more than halfway down the lacrimal sac.3. It was feasible for lacrimal sac exposure in dacryocystorhinostomy by lacrimal bone access anterior to the lower part of the unciform process. The average duration of operation was55.6±10.5min, with no ensuing orbital lamina damage.4. The results included complete cure(18cases,64.29%):no epiphora with patent lacrimal passage; improved (5cases,17.86%):occasional epiphora with limited patency of lacrimal passage; and no effect (5cases,17.85%). There is a higher rate of recovery in the patients with1d-4w disease course than in patients with4w±24w disease course [94.73%(18/19)vs55.56%(5/9), p<0.05](Tab.3-1).Conclusions:1. Computed tomographic dacryocystography(CTDCG) is a useful diagnostic tool for lacrimal passage injury combined with mid-face fractures. 2. The opercule of the middle turbinate(OMT) is located a little more than halfway down the lacrimal sac. It is appropriate to nibble open the lower part of lacrimal sac fossa, then surpass the OMT above1time the distance to expose the lacrimal sac completely in DCR.3. Lacrimal passage decompression is a useful technique to deal with traumatic lacrimal passage injury. It creates conditions for canaliculus or nasolacrimal duct intubation, contribute to the early treatment of and rehabilitation of traumatic lacrimal passage injury.4. It is a simple, safe and effective technique to expose the lacrimal sac through lacrimal bone access anterior to the lower part of the unciform process in DCR, especially suitable to locate and expose the lacrimal sac in the cases of the lacrimal passage injury combined with mid-face fractures.5. Early treatments such as lacrimal sac decompression, canaliculus intubation and lacrimonasal duct intubation have good effects on patients with traumatic lacrimal passage damage.General conclusions:1. The application of Software Mimics, Hypermesh and ABAQUS in the construction of finite element model of maxillary complex is feasible and effective to simulate traumatic environment on the model and thus provide the biomechanical basis of traumatic lacrimal passage injury. By simulating the situation of traffic accident(the prominent positions such as nasal dorsum, zygomatic bone and nasal floor impacting on the ground) with this model, visible stress contribution and displacement can be observed around the frontal process of the maxillary bone (the lacrimal passage area),, which is bigger than that of the frontozygomatic suture and the anterior-lateral wall of maxillary sinus, where the thin and closely connected bones are prone to fracture.2. The anterosuperior part of the lacrimal sac fossa corresponding to the frontal processes of the maxillary bone is thicker than the posteroinferior part which corresponding to lacrimal bone. The uncinate process was more frequently posterior to the lacrimal fossa at the lower level, then adjacent to lacrimal bone or the frontal process of maxillary bone at the intermediate level, last adjacent to the lateral middle turbinate or orbital lamina at the upper level.
【Key words】 uncinate process; lacrimal fossa; lacrimal bone; finite elementanalysis; CTDCG; lacrimal passage decompression;