Visual/Inertial Detection of Trocar and Remote Centre of Motion in Vitreoretinal Surgery

本博士项目涉及提高锁孔显微手术的安全性。锁孔显微手术是在严格的精度要求下进行的，在许多情况下，需要达到人类能力极限的灵巧度。一个这样的例子是玻璃体视网膜手术，在这种手术中，必须操纵人类头发级别的极其微小的结构。即将到来的玻璃体视网膜手术干预将要求更低的精度，以便再生疗法能够被提供给特定的视网膜层，其厚度约为10-20微米。在玻璃体视网膜手术中，临床医生操纵通过作为支点的眼上的套管针/孔插入的器械。因此，应该在这个支点形成一个遥远的运动中心，否则就会有创伤的风险，因为工具拉动组织而不是枢转。例如，眼睛的组织有被撕裂的危险，例如导致散光或晶状体移位。当这类手术是手动进行时，临床医生会使用触觉反馈，以了解是否施加了过大的力。随着玻璃体视网膜手术慢慢考虑机器人的使用，重要的是要开发机制来了解支点和远程运动中心是否相同。了解这一点可以提高安全性，但也允许对眼睛等悬挂器官进行双手操作。虽然正在研究开发能够理解外力大小的力传感器，但我们感兴趣的是开发一种视觉/惯性方法来解决这个问题。这将需要对现有仪器进行最低限度的定制，从而使它们能够在即将到来的机器人辅助下使用。具体地说，这个PHD项目中的关键问题是：1)我们是否可以以可接受的方式使用微型相机和惯性传感器对现有的玻璃体视网膜手术器械进行改造，以支持这种方法的开发？2)同步定位和测绘(SLAM)能否与微型相机和惯性测量一起使用来定位套管针并计算远程运动中心？3)能否将有关远程运动中心和套管针的信息提供给机器人助手以提高安全性？

This PhD project pertains to improving safety in keyhole micro-surgery. Keyhole micro-surgery takes place under strict precision requirements, and, in many cases, requires dexterity that is at the limits of human capabilities. One such example is vitreoretinal surgery, where extremely small structures on the order of the human hair must be manipulated. Upcoming vitreoretinal surgical interventions would require precision even below that, so that regenerative therapies can be delivered to specific retinal layers, which have a thickness on the order of 10-20um.In vitreoretinal surgery, the clinician manipulates an instrument inserted through a trocar/hole on the eye that acts as the fulcrum point. Therefore, a remote centre of motion should be formed at this fulcrum point, as otherwise there is the risk of trauma as the tool pulls on the tissue rather than pivoting. For example, there is the danger that the eye's tissue will be pulled apart, causing, for example, astigmatism or lens displacement. When such surgeries are manually performed, the clinician uses haptic feedback in order to understand that excessive forces are applied. As vitreoretinal surgery slowly considers the use of robotics, it is important to develop mechanisms to understand whether the fulcrum point and remote centre of motion are identical. Knowledge of this improves safety but also allows the bimanual manipulation of suspended organs such as the eye. While there is research on developing force sensors that understand the amount of applied force, we are interested in developing a visual/inertial approach to tackle this problem. This would require the minimum customisation of existing instruments, therefore enabling their use from upcoming robotic assistants.Specifically, the key questions in this PhD project are:1) Can existing vitreoretinal surgical instruments we retrofitted in an acceptable fashion with miniature cameras and inertial sensors to support the development of such an approach?2) Can Simultaneous Localisation and Mapping (SLAM) be used in conjunction with miniature cameras and inertial measurements to localise the trocar and calculate the remote centre of motion?3) Can the information about the remote centre of motion and trocar be provided to a robotic assistant to improve safety?