Biomechanical Analysis in Strabismus Surgery

描述(由申请人提供)：我们提出了四个相互关联的子项目，以定义眼旋转(眼外)肌(EOMS)和其他组织在健康和疾病中的生物力学，了解EOM的新作用，并表征神经损伤对EOMS的影响。这一努力是为了改善斜视的诊断和手术治疗，斜视是指两只眼睛的方向不一致。目的我将阐明结缔组织变性在成人常见形式斜视中的作用，验证某些形式的获得性水平或垂直复视是由结缔组织变性引起的假设，而不是现在普遍认为的大脑或神经疾病，而是结缔组织变性改变了EOM路径。这种退化并不意味着神经系统疾病，但可以通过手术纠正。目的分析眼外膜手术治疗的常见临床斜视综合征，包括滑车麻痹、动眼神经和外展神经的神经损伤对眼外膜的影响，以阐明眼外膜变薄、拉伸、受损神经可能再生或被其他神经替代等力学改变的时间进程和程度。平行研究将通过与显微镜变化的比较来验证眼窝的磁共振成像(MRI)，以提高诊断的特异性。目的III将测试一个新的假设，即对EOMS的个别部分进行选择性的神经控制，允许他们具有目前在其生理曲目中未考虑的重要机械动作，从而使治疗斜视的临床医生感到困惑。对肌内神经分布的微观研究将得到功能研究的补充，使用结构和运动编码的磁共振成像在双目凝视变化、向近靶点会聚和头部倾斜期间进行功能研究，以确定选择性EOM动作对双眼对准的影响。目的利用有限元分析(FEA)的现代机械工程技术对眼眶纤维肌肉组织的行为进行表征和建模，利用最小压痕和以逼真的速度和加速度进行双模式加载的新技术获得的EOM和结缔组织特性的数据。生物力学测试将测试EOMS中选择性间隔作用的潜力。以准确的生物力学数据为基础的有限元分析，将三维计算机可视化与手术前后的MRI进行对比，以了解和改进结缔组织退行性变所致复视的手术治疗。 公共卫生相关性：斜视是一种常见的临床疾病，眼睛不对准会导致成人复视，儿童视力丧失。斜视的治疗通常是通过手术操作眼窝肌肉和结缔组织的机械特性来进行的。加强对眼窝组织力学特性和神经控制的了解，将提高眼部和脑部疾病的诊断水平，提高斜视手术的成功率。

DESCRIPTION (provided by applicant): We propose four interrelated subprojects to define the biomechanics of the eye rotating (extraocular) muscles (EOMs) and other tissues in health and disease, understand novel EOM actions, and characterize effects of nerve damage to EOMs. This effort is to improve diagnosis and surgical treatment of strabismus, which is misalignment of the directions of the two eyes. Aim I will clarify the role of connective tissue degeneration in common forms of strabismus that develop in adults, testing the hypothesis that some forms of acquired horizontal or vertical double vision are caused, not by brain or nerve disease as widely supposed now, but instead by connective tissue degeneration that alters EOM paths. Such degeneration would not signify neurological disease but may be corrected by surgery. Aim II will characterize effects of nerve damage on EOMs in common clinical strabismus syndromes treated by EOM surgery, including palsy of the trochlear, oculomotor, and abducens nerves, to clarify the time course and extent of mechanical changes such as EOM thinning and stretching, and possibly regrowth of damaged nerves or substitution by other nerves. Parallel studies will validate magnetic resonance imaging (MRI) of the eye sockets by comparison with microscopic changes to improve diagnostic specificity. Aim III will test a new hypothesis that nerve control selective for individual parts of EOMs permits them to have important mechanical actions not currently considered in their physiological repertoire, and hence confounding to clinicians who treat strabismus. Microscopic studies of intramuscular nerve distributions will be complemented by functional studies using structural and motion encoded MRI during binocular gaze changes, convergence to near targets, and head tilting to determine the influence of selective EOM actions on binocular alignment. Aim IV will characterize and model behavior of orbital fibromuscular tissues, using the modern mechanical engineering technique of finite element analysis (FEA) to integrate data on EOM and connective tissue properties obtained using novel techniques of minimal indentation, and dual-mode loading at lifelike speed and acceleration. Biomechanical testing will test the potential for selective compartmental action in EOMs. FEA based on accurate biomechanical data will be compared using 3-dimensional computer visualization with pre- and post-operative MRI to understand and improve surgical treatment of double vision caused by connective tissue degeneration. PUBLIC HEALTH RELEVANCE: Strabismus is a common clinical disorder in which misalignment of the eyes can cause double vision in adults, and visual loss in children. Strabismus is often treated by surgical manipulation of mechanical properties of muscles and connective tissues in the eye socket. Improved understanding of mechanical properties and nerve control of eye socket tissues will improve the diagnosis of eye and brain diseases, and enhance the success of strabismus surgery.