A Stability and Safety Control Method in Robot-Assisted Decompressive Laminectomy Considering Respiration and Deformation of Spine

Robot-assisted decompressive laminectomy is a new strategy in clinical applications. However, a stable contact force between the bone-cutting device and lamina is needed to keep it working correctly, which may be affected by respiration and deformation. The surgeon can adapt to this dynamic process quickly, but the robot could cause a considerable force that may damage the patient. This paper proposes a compensation control method based on a respiration-spine model to first improve the stability of the contact force. The model is established based on human morphology and ventilator parameters for anaesthetised patients. The control method is a combination of a surgery sleeve and active fuzzy control to improve the robustness of the robot. The control of the sleeve is related to the thickness of the bone layer, which can be calculated from the image. Furthermore, the lower boundary of the lamina in the CT image is extracted as a safety constraint that can protect the spinal nerves. Finally, an experiment is conducted to verify the safety constraint and compare the changes in contact force with or without the control method. The statistical experiment shows that the control error is 2.47 N without the force control method, while the force control error is 0.223 N when the target control force is 2 N. The robot will hover on the surface of the spine after completing the laminectomy of the planned area. These results show that the robot can be controlled safely and stably. Note to Practitioners—The purpose of this paper is to propose a stable and safe control method for lamina grinding robots under the influence of breathing and deformation factors. Most previous research only considered one of the two factors, and both factors are considered in this paper. Unlike the surgeon, who has the ability to adapt to physiological movements, the robot may cause a considerable force to be exerted on the device, which may damage the patient. Therefore, a controller based on human experience is longitudinally designed, and position constraints are added in three directions. This application can improve the stability and safety of robot-assisted surgery, which may be suitable for remote surgery and can help rural areas solve the problem of a lack of medical resources. Spinal model bone experiments have been completed and will be tested on animals in the future.