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（EOM）和健康和疾病中的其他组织的生物力学，了解新的EOM动作，并表征神经损伤对EOM的影响。这一努力是为了提高斜视的诊断和手术治疗，斜视是两眼方向不一致。目的：我将阐明结缔组织变性在成人常见斜视中的作用，检验以下假设：某些形式的后天性水平或垂直复视不是由现在广泛认为的脑或神经疾病引起的，而是由改变眼外肌路径的结缔组织变性引起的。这种变性并不意味着神经系统疾病，但可以通过手术纠正。目的II将描述眼外肌手术治疗的常见临床斜视综合征中神经损伤对眼外肌的影响，包括滑车神经、眼神经和外展神经的麻痹，以阐明机械变化的时间过程和程度，如眼外肌变薄和拉伸，以及受损神经的可能再生或被其他神经替代。平行研究将通过与显微镜变化进行比较来验证眼窝的磁共振成像（MRI），以提高诊断特异性。目的III将测试一个新的假设，即选择性神经控制个别部分的眼外肌允许他们有重要的机械动作，目前没有考虑在他们的生理剧目，因此混淆临床医生治疗斜视。肌内神经分布的显微镜研究将补充功能研究，使用结构和运动编码的MRI在双目凝视变化，收敛到近目标，和头部倾斜，以确定选择性眼外肌行动对双眼对齐的影响。目的IV将表征和建模眼眶纤维肌组织的行为，使用有限元分析（FEA）的现代机械工程技术来整合使用最小压痕和双模加载逼真的速度和加速度的新技术获得的EOM和结缔组织特性的数据。生物力学测试将测试EOM中选择性房室作用的潜力。基于精确生物力学数据的FEA将使用三维计算机可视化与术前和术后MRI进行比较，以了解和改善结缔组织变性引起的复视的手术治疗。

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.