He Changyan, Yang Emily, Iordachita Iulian
Annu Int Conf IEEE Eng Med Biol Soc. 2019 Jul;2019:3212-3216. doi: 10.1109/EMBC.2019.8857739.
Retinal vein cannulation is a promising treatment for retinal vein occlusion that involves the injection of an anticoagulant directly into the occluded vein to dissolve the blockage. However, excessive forces applied by the injection tool during the procedure, at either the scleral incision or injection site, can result in injury to the eye. Furthermore, the force required to puncture retinal veins (around 10 mN) is well below human sensing ability and an order of magnitude smaller than those that can be safely applied at the sclera (around 100 mN). Detection and management of tool-to-tissue forces on these different scales are some of the most challenging aspects of the cannulation procedure. This work describes the development of a sensorized cannulation tool capable of detecting both tool-to-vein puncture forces and tool-to-sclera contact forces. By combining two materials, nitinol alloy for the tool tip and stainless steel for the tool shaft, to achieve dual stiffness, the tool possesses a flexible tip to capture small vein puncture forces and a stiffer shaft to maintain straightness during use. Three segments of fiber Bragg grating sensors are calibrated to measure the transverse forces at both the tool tip and sclerotomy, as well as to determine the tool insertion depth within the eye. The results of the validation experiments show that the root mean square error of the measurements for the force at the tip, the force at the sclerotomy, and the tool position are 0.70 mN, 1.59 mN, and 0.69 mm, respectively.
视网膜静脉插管是一种有前景的视网膜静脉阻塞治疗方法，该方法涉及将抗凝剂直接注入阻塞静脉以溶解血栓。然而，在手术过程中，注射工具在巩膜切口处或注射部位施加的过大力量可能会导致眼睛受伤。此外，穿刺视网膜静脉所需的力量（约10毫牛）远低于人类的感知能力，且比在巩膜处可安全施加的力量（约100毫牛）小一个数量级。检测和管理这些不同尺度下工具与组织之间的力是插管手术中最具挑战性的方面之一。这项工作描述了一种带有传感器的插管工具的开发，该工具能够检测工具与静脉穿刺的力以及工具与巩膜的接触力。通过结合两种材料，工具尖端采用镍钛诺合金，工具杆采用不锈钢，以实现双重刚度，该工具具有灵活的尖端来捕捉较小的静脉穿刺力，以及较硬的杆在使用过程中保持笔直。三段光纤布拉格光栅传感器经过校准，以测量工具尖端和巩膜切开处的横向力，并确定工具在眼内的插入深度。验证实验结果表明，尖端力、巩膜切开处力和工具位置测量的均方根误差分别为0.70毫牛、1.59毫牛和0.69毫米。
