“A New Platform for Surgical Intervention: An MRI Compatible Pediatric Surgical Robot”

The Pediatric Surgery Robot in (PSR) is a 5-DOF robot, capable of 7-DOF actuation various other tooling modes. It is designed to fit within a Philips Achieva 3.0T MRI bore. A surgical pre-planning and control interface has been developed for joint and Cartesian level control. The PSR-BBT has demonstrated 1.65 +/- 1.77 mm in Cartesian control in free space. The PSR-BBT can generate 12.46 +/- 0.32 N of axial force while drilling at a speed of 30 rpm, which is sufficient for cortical and cancellous bone phantoms. Under MRI testing with T1-FFE, T1-SE, T2-FFE and T2-TSE scans, the system demonstrated less than 27% signal-to-noise ratio variation while drilling and less than 0.55% geometric distortion without significantly impacting MRI guidance in situ. The ability of simultaneous imaging and surgical intervention provides an opportunity to reduce procedure duration and errors. 

“Development and Validation of MRI Compatible Pediatric Surgical Robot with Modular Tooling for Bone Biopsy”

Bone marrow aspiration and bone marrow trephine biopsy are essential for the diagnosis of hematological malignancies and nonmalignant diseases in children. In clinical practice, magnetic resonance imaging (MRI) is used to locate the lesion/tumor prior to the biopsy or aspiration. However, there is a significant lack of MR-compatible tools that can be used simultaneously during imaging and biopsy while maintaining surgical accuracy and safety. Additionally, the lack of simultaneous imaging means that the procedures are non-line-of-sight, offering limitations on intraoperative corroboration of sample capture which results in a significant reduction in accuracy and safety. The Pediatric Surgery Robot in (PSR) is a 5-DOF robot, capable of 7-DOF actuation in Bone Biopsy Tooling (BBT) mode. It is designed to fit within a Philips Achieva 3.0T MRI bore and carry a modified titanium bone biopsy needle. A surgical pre-planning and control interface has been developed for joint and Cartesian level control. The PSR-BBT has demonstrated 1.65 +/- 1.77 mm in Cartesian control in free space. The PSR-BBT can generate 12.46 +/- 0.32 N of axial force while drilling at a speed of 30 rpm, which is sufficient for cortical and cancellous bone phantoms. Under MRI testing with T1-FFE, T1-SE, T2-FFE and T2-TSE scans, the system demonstrated less than 27% signal-to-noise ratio variation while drilling and less than 0.55% geometric distortion without significantly impacting MRI guidance in situ. The ability of simultaneous imaging and surgical intervention provides an opportunity to reduce procedure duration and errors. 

“Design and Fabrication of a MRI Guided Robotic Deep Brain Stimulation Electrode Implantation Tool”

Deep Brain Stimulation (DBS) is a procedure that has had success at controlling a variety of movement disorders such as Parkinson’s Diseases and Essential Tremors. The procedure has traditionally been performed as an awake brain surgery procedure. Pre-operative MRI is used for path planning, and Micro Electrode Recording (MER) is used to locate the subthalamic nucleus (STN), requiring patient feedback during the procedure to determine if the position is correct based on symptomatic relief. The microelectrodes are re-inserted repeatedly until the correct spot is found, which can potentially result in bleeding, stroke, and brain damage.   A 2011 study from the Department of Neurosurgery, Rush University Medical Center found that traditional methods of DBS lead implantation using awake brain surgery and MER targeting had an accuracy of 2.62 ± 1.5 mm between the intended placement and the actual placement as determined in a post-operative MRI . 

A robotic system using MRI guidance has the potential to increase the implantation accuracy by enabling simultaneous visualization of the target and probe throughout the procedure. The tool being developed will be operated on the Paediatric Surgical Robot (PSR), a 5-DOF MRI-guided surgical robot, compatible with the Philips Achieva 3.0 T MRI. The tool is designed to implant the Medtronic 3389 DBS probe. In previous tests, the PSR was shown to have an accuracy of 1.65 +- 1.77 mm in free space . The linear accuracy and deflection of the DBS Tool will be characterized after fabrication is completed and is designed to travel a linear distance of 150 mm and retain a linear speed of 1 cm/sec with linear resolution of 0.5 um. In addition needle steering is implemented to counter the effects of probe deflection that are expected to occur during the surgical procedure. A robotic system of DBS implantation has the potential to increase accuracy, shorten the duration of the surgery, and ultimately improve patient outcomes.

“A Contact-Aided Compliant Gear Topology to Enhance Joint Stiffness in Millimeter-Scale Neurosurgical Tools for the da Vinci Research Kit”

We present the development of a novel contact-aided compliant mechanism (CCM) incorporated into a notched-tube joint. This design is applied to the development of a millimeter-scale, articulate, tube-shaft instrument for minimally invasive surgery (MIS). Here, the CCM topology addresses the joint performance trade-off between stiffness, range of motion, and joint compactness when designing notched-tube instruments for milli- -meter-scale surgery. Specifically, the CCM design offers an increased blocking force at the distal end and reduced stress concentrations. The kinematic model and the finite element modeling (FEM) results are used to validate the experimental performance of the CCM under different loading and articulation scenarios. The improved stiffness offers higher blocking force resistance at ##%, ##%, and ##% at the distal end for articulation at 0o, 10o, and 20o bending angles, respectively. This novel design is implemented into a robotic neurosurgical tool for the da Vinci Research Kit that incorporates a 3DoF wrist for precision