A New Approach in High Precision Bone Surgery: Semi-Automatic Alignment of an Application-Specific Instrument Guide Adjusted by a Smart Screwdriver

Abstract

Robotic surgical systems reduce the cognitive workload of the surgeon by assisting in guidance and operational tasks. As a result, higher precision and a decreased surgery time are achieved, while human errors are minimised. However, most of robotic systems are expensive, bulky and limited to specific applications.In this paper a novel semi-automatic robotic system is evaluated that offers the high accuracies of robotic surgery while remaining small, universally applicable and easy to use. The system is composed of a universally applicable handheld device, called Smart Screwdriver (SSD) and an application specific kinematic chain serving as a tool guide. The guide mechanism is equipped with motion screws. By inserting the SSD into a screw head, the screw is identified automatically and the required number of revolutions is executed to achieve the desired pose of the tool guide.The usability of the system was evaluated according to IEC 60601-1-6 using pedicle screw implementation as an example. The achieved positioning accuracies of the drill sleeve were comparable to those of SpineAssist from Mazor Robotics Ltd., Caesarea (IL) with -0.54 ± 0.93 mm (max: 2.08 mm) in medial/lateral-direction and 0.17 ± 0.51 mm (max: 1.39 mm) in cranial/caudal-direction in the pedicle isthmus. Additionally, the system is cost-efficient, safe, easy to integrate in the surgical workflow and universally applicable to applications in which a static position in one or more DOF is to be adjusted.

Modular design of versatile surgical mini-robots

“…Apart from parts for fixation and registration, the SSD system consists of two major modules: a sterile universal drive unit (1 DOF), called Smart Screwdriver, and an adjustable, application-specific passive kinematic structure for positioning the related tool guide [10]. Whereas so far passive kinematic structures for three different surgical applications have been designed (hip resurfacing (HR; 4 DOF), pedicle screw placement (PSP; 4 DOF) and total knee arthroplasty (TKA; 3 DOF)), all applications are using the same sterile universal SSD unit [11,13]. The kinematic structure for PSP (module "SpinePilot"), illustrated in Figure 3, is equipped with four motion screws (each for one DOF) in order to enable the motion of the guide sleeve.…”

“…The motion screws are actuated and rotated by inserting the SSD in an arbitrary sequence. [10,13] Figure 2: The SSD and SpinePilot module for pedicle screw placement [10,13] In contrast to the drive train of the MINARO system, the inner part of the wireless SSD is non-sterilisable (due to some additional heat sensitive electronic components such as batteries and Bluetooth components) and has to be removed before reprocessing. All other parts are autoclavable.…”

“…Both systems were evaluated regarding their usability (DIN EN 60601-1-6) according to the criteria effectiveness, efficiency, learnability and user satisfaction with positive results in previous studies [11,12,13]. Risk analyses were conducted according to DIN EN ISO 14971 by using the CARAD software tool from SurgiTAIX GmbH, Herzogenrath (Germany) and the mAIXuse method for manmachine interaction developed at our chair [14].…”