MINARO HD: control and evaluation of a handheld, highly dynamic surgical robot.

PURPOSE: Current surgical robotic systems are either large serial arms, resulting in higher risks due to their high inertia and no inherent limitations of the working space, or they are bone-mounted, adding substantial additional task steps to the surgical workflow. The robot presented in this paper has a handy and lightweight design and can be easily held by the surgeon. No rigid fixation to the bone or a cart is necessary. A high-speed tracking camera together with a fast control system ensures the accurate positioning of a burring tool. METHODS: The capabilities of the robotic system to dynamically compensate for unintended motion, either of the robot itself or the patient, was evaluated. Therefore, the step response was analyzed as well as the capability to follow a moving target. RESULTS: The step response show that the robot can compensate for undesired motions up to 12 Hz in any direction. While following a moving target, a maximum positioning error of 0.5 mm can be obtained with a target motion of up to 18 mm/s. CONCLUSION: The requirements regarding dynamic motion compensation, accuracy, and machining speed of unicompartmental knee arthroplasties, for which the robot was optimized, are achieved with the presented robotic system. In particular, the step response results show that the robot is able to compensate for human tremor.

Smart bioimpedance-controlled craniotomy: Concept and first experiments.

Craniotomy is part of many neurosurgical interventions to create surgical access to intracranial structures. The procedure conventionally bears a high risk of unintended dural tears or damage of the soft tissue underneath the bone. A new synergistically controlled instrument has recently been introduced to address this problem by combining a soft tissue preserving saw with an automatic cutting depth control. Many approaches are known to obtain the information required on the local bone thickness. However, they suffer from unsatisfactory robustness against disturbances occurring during surgery and many approaches require additional intra- or preoperative steps in the workflow. This article presents first concepts for real-time cutting depth control based on in-process bioimpedance measurements. Furthermore, sensor integration into a synergistic surgical device incorporating a bidirectional oscillating saw is demonstrated and evaluated in first feasibility tests on a fresh bovine bone specimen. Results of bipolar measurements show that the transition of different layers of bicortical bone and bone breakthrough lead to characteristic impedance patterns that can be used for process control.

Modular design of a miniaturized surgical robot system.

Currently, there are only a small number of robotic systems used in various surgical fields. As modified industrial robot systems have shown significant limitations in the past, specialized kinematic solutions have been proposed for specific surgical applications. The majority of these systems are designed for specific applications in only a limited number of cases. The acquisition and operating costs are high, hindering the dissemination and broad clinical application of such systems. To address this problem, a modular mini-robot system is proposed, which can be easily adapted to different application-specific requirements. Therefore, the requirements of different applications have been categorized and clustered to a standardized requirement profile. Next, a modular robot based on a hybrid kinematic module structure has been developed. This concept has been implemented and tested in in vitro studies for different applications, such as revision total hip replacement and unicondylar knee arthroplasty. User-orientated tests of the intraoperative handling, as well as accuracy tests, proved the feasibility of the concept.