A Commercially Available Capacitive Stretch-Sensitive Sensor for Measurement of Rotational Neck Movement in Healthy People: Proof of Concept.

Freedom of neck range of motion has been identified for decades as an important indicator of neck health. In the past, neck motion has been measured in clinical settings using straight-plane movements that do not represent real-world 'ecological' performance. The tools currently used are low-fidelity analog or digital tools that rely greatly on the orientation of the person with respect to gravity, or the evaluator's ability to accurately align protractor arms with key surface markers for angle measurement. A possible solution lies in the use of wearable sensors for tracking the motion of the neck without clinical instruction. For this purpose, the focus of this paper is on the assessment of a commercially available stretch sensitive sensor, C-Stretch® against a gold standard for motion tracking. The sensor's accuracy and agreement for measuring neck rotations were evaluated. The results show that the stretch sensitive sensor was accurate with an average RMSE of 5.86° (SD=$4.38^{\circ}, \mathrm{n}=2$) and highly correlated $r=0.88-0.99,(p\lt0.01)$ with Aurora, an electromagnetic tracking system. This work may lead to using wearable sensors as a cost-effective, lightweight, and safe alternative to assess real-world neck range of motion for clinical application.

Characterization of Parkinsonian Hand Tremor and Validation of a High-Order Tremor Estimator.

Recent progress in wearable technology has made wearable tremor suppression devices (WTSDs) for Parkinson's patients a potentially viable alternative solution for tremor management. So far, in contrast to wrist and elbow tremor, finger tremors have not been studied in depth despite the huge impact that they have on a patient's daily life. In addition, more evidence has been found showing that the performance of current tremor estimators may be limited by their model order due to the multiple harmonics present in tremor. The aim of this paper is to characterize finger and wrist tremor in both the time and frequency domains, and to propose a high-order tremor estimation algorithm. Tremor magnitudes are reported in the forms of linear acceleration, angular velocity, and angular displacement. The activation of forearm flexor and extensor muscles is also investigated. The frequency analysis shows that Parkinsonian tremors produce oscillations of the hand with pronounced harmonics. At last, a high-order weighted-frequency Fourier linear combiner (WFLC)-based Kalman filter is proposed. The percentage estimation accuracy achieved from the proposed estimator is 96.3 ± 1.7%, showing average improvements of 28.5% and 48.9% over its lower-order counterpart and the WFLC. The proposed estimator shows promise for use in a WTSD.

Design and validation of a high-order weighted-frequency fourier linear combiner-based Kalman filter for parkinsonian tremor estimation.

The design of a tremor estimator is an important part of designing mechanical tremor suppression orthoses. A number of tremor estimators have been developed and applied with the assumption that tremor is a mono-frequency signal. However, recent experimental studies have shown that Parkinsonian tremor consists of multiple frequencies, and that the second and third harmonics make a large contribution to the tremor. Thus, the current estimators may have limited performance on estimation of the tremor harmonics. In this paper, a high-order tremor estimation algorithm is proposed and compared with its lower-order counterpart and a widely used estimator, the Weighted-frequency Fourier Linear Combiner (WFLC), using 18 Parkinsonian tremor data sets. The results show that the proposed estimator has better performance than its lower-order counterpart and the WFLC. The percentage estimation accuracy of the proposed estimator is 85±2.9%, an average improvement of 13% over the lower-order counterpart. The proposed algorithm holds promise for use in wearable tremor suppression devices.

Toward construct validity for a novel sensorized instrument-based minimally invasive surgery simulation system.

Minimally invasive surgical training is complicated due to the constraints imposed by the surgical environment. Sensorized laparoscopic instruments capable of sensing force in five degrees of freedom and position in six degrees of freedom were evaluated. Novice and expert laparoscopists performed the complex minimally invasive surgical task of suturing using the novel instruments. Their force and position profiles were compared. The novel minimally invasive surgical instrument proved to be construct valid and capable of detecting differences between novices and experts in a laparoscopic suturing task with respect to force and position. Further evaluation is mandated for a better understanding of the ability to predict performance based on force and position as well as the potential for new metrics in minimally invasive surgical education.

New tactile sensing system for minimally invasive surgical tumour localization.

BACKGROUND: Minimally invasive surgery (MIS) suffers from the inability to directly palpate organs for tumour localization. A tactile sensing system (TSS), consisting of a probe and a visualization interface, was developed to present an active pressure map of the contact surface to locate tumours during MIS. METHODS: The TSS performance was compared to MIS graspers to locate occult 10 mm phantom tumours in ex vivo bovine liver and ex vivo porcine lung. Performance assessment included applied pressure, localization distance and accuracy. RESULTS: The TSS realized a relative 71% reduction in maximum applied pressure and a 31% increase in detection accuracy in liver tissue (when compared to MIS graspers) and demonstrated no significant differences in performance when palpating lung tissue. CONCLUSIONS: The TSS may help surgeons to identify occult tumours during surgery by restoring some of the haptic information lost during MIS.

Electromagnetic navigation improves minimally invasive robot-assisted lung brachytherapy.

OBJECTIVE: Recent advances in minimally invasive thoracic surgery have renewed an interest in the role of interstitial brachytherapy for lung cancer. Our previous work has demonstrated that a minimally invasive robot-assisted (MIRA) lung brachytherapy system produced results that were equal to or better than those obtained with standard video-assisted thoracic surgery (VATS) and comparable to results with open surgery. The purpose of this project was to evaluate the performance of an integrated system for MIRA lung brachytherapy that incorporated modified electromagnetic navigation and ultrasound image guidance with robotic assistance. METHODS: The experimental test-bed consisted of a VATS box, ZEUS and AESOP surgical robotic arms, a seed injector, an ultrasound machine, video monitors, a computer, and an endoscope. Our previous custom-designed electromagnetic navigational software and the robotic controller were modified and incorporated into the MIRA III system to become the next-generation MIRA IV. Inactive brachytherapy seeds were injected as close as possible to a small metal ball target embedded in an opaque agar cube. The completion time, the number of attempts, and the accuracy of seed deployment were compared for manual placement, standard VATS, MIRA III, and the new MIRA IV system. RESULTS: The MIRA IV system significantly reduced the median procedure time by 61% (104 s to 41 s), tissue trauma by 75% (4 attempts to 1 attempt), and mean seed placement error by 64% (2.5 mm to 0.9 mm) when compared to a standard VATS. MIRA IV also reduced the mean procedure time by 48% (85 s to 44 s) and the seed placement error by 68% (2.8 mm to 0.9 mm) compared to the MIRA III system. CONCLUSIONS: A modified integrated system for performing minimally invasive robot-assisted lung brachytherapy was developed that incorporated electromagnetic navigation and an improved robotic controller. The MIRA IV system performed significantly better than standard VATS and better than MIRA III.

Feasibility of locating tumours in lung via kinaesthetic feedback.

BACKGROUND: Localizing lung tumours during minimally invasive surgery is difficult, since restricted access precludes manual palpation and pre-operative imaging cannot map directly to the intra-operative lung. This study analyses the force-sensing performance that would allow an instrumented kinaesthetic probe to localize tumours based on stiffness variations of the lung parenchyma. METHODS: Agar injected into ex vivo porcine lungs produced a model approximating commonly encountered tumours. Force-deformation data were collected from multiple sites at various palpation depths and velocities, before and after the tumours were injected. RESULTS: Analysis showed an increase in force after the tumours were injected, in the range 0.07-0.16 N at 7 mm (p < 10(-4)). A 2 mm/s palpation velocity minimized exponential stress decay at constant depths, facilitating easier comparisons between measurements. CONCLUSION: A sensing range of 0-2 N, with 0.01 N resolution, should allow a kinaesthetic palpation probe to resolve local tissue stiffness changes that suggest an underlying tumour.

Optimizing port placement for robot-assisted minimally invasive cardiac surgery.

BACKGROUND: Proper placement of ports during robot-assisted endoscopic surgery is critical to the success of the procedure. In current practice, port placement methods do not consider the ability of the robot to manoeuvre the tools. METHODS: This paper proposes to choose the best port location such that the performance of the robot is maximized. The Global Conditioning Index (GCI) is used to optimize port placement when using the da Vinci((R)) surgical system during cardiac surgery. RESULTS: The results show that, due to a singularity at the remote centre of motion, higher performance is obtained the further away the port is from the workspace. When compared to the ports selected by an expert surgeon, our results show that it is possible to increase robot performance by at least 29% for the left arm of the robot. CONCLUSIONS: Selecting an adequate port location can improve robot performance and ensure that the instruments reach the surgical site.

Robot-assisted minimally invasive lung brachytherapy.

BACKGROUND: This paper presents a novel alternative for the treatment of lung cancer. The method consists of accessing the lung through small incisions in a minimally invasive manner in order to insert radioactive seeds directly into the lung using a robotic surgical system. METHODS: An experimental test-bed to evaluate the feasibility of this approach has been developed. It consists of two surgical robotic systems, a device specifically designed to robotically implant radioactive seeds, needle tracking software, ultrasound imaging, electromagnetic tracking, and a surgical box that mimics a patient's thorax. A detailed comparison has been performed between currently available access options and robot-assisted minimally invasive access. RESULTS: The results show insignificant differences in accuracy between the methods, with the exception of a significant improvement when electromagnetic (EM) guidance was added to the non-robotic techniques. The navigation system reduced the number of attempts for all seed delivery methods. Significant reductions in time were achieved in the minimally invasive procedures by the addition of EM guidance. CONCLUSIONS: The performance achieved when using robotic systems and image guidance for minimally-invasive brachytherapy is clinically comparable to that achieved in an open surgery procedure, while reducing the invasiveness of the procedure, improving ergonomic conditions for the clinician and reducing radiation exposure.