Collaborative Research: Physics-Based Modeling and Simulation for Post-Mastectomy Breast Reconstructive Surgery

乳腺癌是当今美国女性中第二常见的癌症诊断，仅次于皮肤癌。乳房切除后乳房重建术是第三种最常用的重建术，仅次于肿瘤切除和手部手术。伴随着乳房肿块和随后的乳房切除而来的心理痛苦，加上当代重建程序的局限性；如果没有可信的重建程序，毁容手术的幽灵会增加恐惧。传统的乳房重建程序，或其他需要脂肪组织的软组织缺陷，都需要“拆东墙补西墙”。也就是说，患者身上供体部位的组织被用来重建接受部位。然而，很难准确地预测在任何特定的患者中，特定的手术将如何改变乳房。多大的供体组织可以产生所需的乳房形状？皮肤会产生多大的张力？是否有足够的组织来重建符合患者期望的乳房？目前，还没有预测手术结果的方法。这项提议的目标是开发一种预测方法，以取代目前正在实施的试错法。该方法基于力学的大变形分析，将覆盖乳房的皮肤模型化为非线性弹性膜或壳，必须确定其力学性质。在知道乳房上的植入组织和皮肤的形状、大小和质量后，将使用非线性分析来计算得到的末端形状。相反，如果规定了端部形状，分析应该产生植入组织的数量，以及所需的皮肤形状和大小。这个项目的具体目标是：1)开发一个分析模型和数值模拟，以使用通用数据以及物理和计算模型来预测已知初始条件下的乳房形状。这是基于有限变形体的力学，2)开发一个参数可变形模型，从数学上描述女性乳房的形状，以及3)使用体模对这些方法进行实验验证，并演示它们在乳房重建手术中的应用。这项研究的成功完成有可能改善乳腺癌切除后重建手术后恢复的个人的生活质量。预测性方法也将导致手术时间的减少。将开发的模型也将适用于其他器官和组织，因此将增加对软组织建模和手术模拟的理解。

0402591KakadiarisBreast cancer is the second most frequent cancer diagnosis among American women today, after skin cancer. Post-mastectomy breast reconstruction is the third most frequently performed reconstructive procedure, superseded only by tumor removal and hand surgery. The psychological distress that accompanies a lump found in the breast, and the subsequent mastectomy is compounded by the limitations of contemporary reconstructive procedures; without a trusted reconstruction procedure, the specter of a disfiguring operation adds to the fear. Conventional procedures for reconstructing breast, or other soft tissue defects requiring adipose tissue, involve "robbing Peter to pay Paul". That is, tissue from a donor site on the patient is used to reconstruct the receiving site. However, it is difficult to predict exactly how the breast will be changed by a specific procedure in any particular patient. What size of donor tissue will yield the desired breast shape? How large a tension will be generated in the skin? Is there enough tissue to recreate a breast that would meet the expectations of the patient? Currently, there are no methods that would predict the outcome of the surgery.The goal of this proposal is to develop a predictive methodology to replace the trial and error method currently practiced. The proposed method is based on the large deformation analysis of mechanics; the skin covering the breast is modeled as a nonlinear elastic membrane or shell whose mechanical properties must be determined. After the shape, the size, and the mass of implant tissue and the skin on the breast are known, a nonlinear analysis will be used to calculate the resulting end shape. Conversely, if the end shape is prescribed, the analysis should yield the amount of implant tissue, and the shape and size of the skin necessary. The specific aims of this project were: 1) to develop an analytical model and numerical simulations to predict the breast shape for known initial conditions using generic data as well as physical and computational phantoms. This is based on the mechanics of finitely deforming bodies, 2) to develop a parametric deformable model that describes the shape of a female breast mathematically and 3) to experimentally verify these methods using phantoms and to demonstrate their utility for breast reconstructive surgery. Successful completion of this research has the potential to improve the quality of life for individuals recovering from post-mastectomy reconstruction operations. The predictive methodology will also lead to reduction in surgical time. The models that will be developed will apply to other organs and tissues as well and thus will increase understanding of soft tissue modeling and surgical simulation.