Journal of Medical Robotics Research

In robotic needle steering, flexible asymmetric-tip needles can steer around obstacles to reach targets deep within tissue. Due to tissue inhomogeneity and needle flexibility, needle buckling can occur, preventing accurate placement. This paper focuses on detecting needle buckling using axial force and needle-tip position readings from sensors. Our algorithm uses errors between the force readings and a predictive force model generated from those readings to track rapid changes in the measured forces. Using this prediction error and needle-tip position, the algorithm detects unexpected force increase, strict needle buckling, and buckling with sliding events at the needle-tip. The metrics for the detections are derived using a standard three-sigma rule and a sigmoid function to ensure generalizability of this method to a variety of tissue types. Our algorithm was tested using insertions into a gelatin tissue with an embedded rectangular obstacle designed to elicit buckling events. Needle buckling was detected at a maximum of 2mm after collision with the obstacle. Our algorithm was tested for robustness with insertions in an ex vivo tissue under different boundary conditions. Our algorithm was also able to detect buckling events 1–2s sooner than human detection times, showing significance for future autonomous control.

This paper presents the development, preclinical evaluation, and preliminary clinical study of a robotic system for targeted transperineal prostate biopsy under direct interventional magnetic resonance imaging (MRI) guidance. The clinically integrated robotic system is developed based on a modular design approach, comprised of surgical navigation application, robot control software, MRI robot controller hardware, and robotic needle placement manipulator. The system provides enabling technologies for MRI-guided procedures. It can be easily transported and setup for supporting the clinical workflow of interventional procedures, and the system is readily extensible and reconfigurable to other clinical applications. Preclinical evaluation of the system is performed with phantom studies in a 3 Tesla MRI scanner, rehearsing the proposed clinical workflow, and demonstrating an in-plane targeting error of 1.5mm. The robotic system has been approved by the institutional review board (IRB) for clinical trials. A preliminary clinical study is conducted with the patient consent, demonstrating the targeting errors at two biopsy target sites to be 4.0mm and 3.7mm, which is sufficient to target a clinically significant tumor foci. First-in-human trials to evaluate the system’s effectiveness and accuracy for MR image-guided prostate biopsy are underway.

Nowadays, robotic systems are an integral part of many orthopedic interventions. Stationary robots improve the accuracy but also require adapted surgical workflows. Handheld robotic devices (HHRDs), however, are easily integrated into existing workflows and represent a more economical solution. Their limited range of motion is compensated by the dexterity of the surgeon. This work presents control algorithms for HHRDs with multiple degrees of freedom (DOF). These algorithms protect pre- or intraoperatively defined regions from being penetrated by the end effector (e.g., a burr) by controlling the joints as well as the device’s power. Accuracy tests on a stationary prototype with three DOF show that the presented control algorithms produce results similar to those of stationary robots and much better results than conventional techniques. This work presents novel and innovative algorithms, which work robustly, accurately, and open up new opportunities for orthopedic interventions.

Context $:$ During laparoscopic sacrocolpopexy, vaginal vault prolapse is repaired by restoring the anatomical state of the vagina with a surgical mesh. A vaginal manipulator is placed inside the vagina to provide proper exposure to the surgeon for fixation of the mesh on the vaginal surface and vault by laparoscopy. Vaginal vault manipulation is done manually by an assistant and long operation times lead to fatigue, inconsistent application of tensioning forces and possibly vaginal rupture. This work describes a novel force sensor designed to be integrated in a vaginal manipulator to measure interaction forces between the vaginal vault and the manipulator. Content $:$ The sensor is characterized and tested in lab-environment. After receiving ethics committee approval two first-in-woman studies have been conducted. Both the force and pose of the instrument were recorded. Conclusions $:$ The force sensor showed to be suited to measure vaginal vault interaction forces and will be embedded in a robotic system for vaginal vault manipulation. Up to now, no previous research has quantified these interaction forces. Quantifying these forces and providing feedback cues to the surgeon is of particular interest, especially as a means to avoid vaginal rupture due to over-tensioning. A total of 30 interventions will be recorded.

Tubular continuum robots can follow complex curvilinear paths to reach restricted areas within the body. Using teleoperation, these robots can help minimize incisions and reduce trauma. However, drawbacks include the lack of haptic feedback and a limited view of the situs, often due to camera occlusion. This work presents novel auditory display to enhance interaction with such continuum robots to increase accuracy and path-following efficiency and reduce cognitive workload. We recreate a typical use case with a test environment that simulates a transnasal intervention through the sphenoidal sinus including a simulated continuum robot. Distance information is mapped to changes in a real-time audio synthesizer using sung voice to provide navigation cues. User studies with novice participants and clinicians were performed to evaluate the effects of auditory display on accuracy, task time, path following efficiency, subjective workload, and usability. When using auditory display, participants exhibit significant increase in accuracy, efficiency, and task time compared to visual-only display. Auditory display reduced subjective workload and raised usefulness and satisfaction ratings. The addition of auditory display for augmenting interaction with a teleoperated continuum robot has shown to benefit performance as well as usability. The method could benefit other scenarios in navigated surgery to increase accuracy and reduce workload.