Research On Path Plan And Safety Control For Robot-assisted Vertebral Lamina Milling

Vertebral lamina milling operation is a key procedure of laminectomy.In order to complete Uni-Or-Bilateral Fenestration to release the pressure on nerves and arteries in the spinal canal,the surgeon needs to hand milling tool to mill out V-slots on the vertebral lamina with the help of navigation equipment.However,the long-time operation may cause the surgeon tired and hands trembling,which will bring the risk that the vital tissues are harmed.Many vital arteries and nerves which establish the connection between the brain and organs are distributed in the spin cord,and it would cause pain,paralysis or death while these tissues are damaged.In recent years,robot technology has been more and more widely applied in the medical field.Some high repeatability,complicated operations and which are under radiation environment in surgery has been replaced or assisted by robot to reduce the probability of error,decrease the requirements for surgeons' skill and physical power and remove the damage to surgeons' health from radiation.This paper presents a new interactive method for robot-assisted laminectomy with safety control based on image-guided navigation and adaptive fuzzy controller.In the CT images,the surgeon can not choose series of points to generate the ideal milling path.So,in this paper,a preoperative milling path-plan method based on threedimensional reconstruction is proposed,which enables the surgeon to choose the milling region in the 3D space.The milling path is generated based on the surfaces of the vertebral lamina,which provides the data support to the robot for automated and precise milling.In the operation,the preoperative planned milling path and CT volume data is registered in the intraoperative space to navigate the robot accomplish milling procedure.During the milling procedure,the transverse milling feed rate is adjusted to stabilize the transverse milling force to improve the dynamic performance of the robot system by an adaptive fuzzy controller—multilevel fuzzy controller.Under the situation of various feed rate by multilevel muzzy controller,a bone texture classifier based on energy-consumed-density feature vector and SVM is come up with to stop the feeding of robot when the inner layer of cortical bone is milled,which guarantees the safety of the milling procedure.The research in this paper improves the applications of robot-assist technology in vertebral lamina milling operation or other milling procedures in orthopedic surgery.