Cinzia Freschi

A Simple Robotic System for Neurorehabilitation

In the recent past, several researchers have shown that important variables in relearning motor skills and in changing the underlying neural architecture after stroke are the quantity, duration, content, and intensity of training sessions. Unfortunately, when traditional therapy is provided in a hospital or rehabilitation center, the patient is usually seen for few hours a week. Robot-mediated therapies could improve this situation but even if interesting results have been achieved by several groups, the use of robot-mediated therapy has not become very common in clinical practice. This is due to many different reasons (e.g., the “technophobia” of some clinicians, the need for more extensive clinical trials) but one of the more important is the cost and the complexity of these devices which make them difficult to be purchased and used in all the clinical centers.The aim of this work was to verify the possibility of improving motor recovery of hemiparetic subjects by using a simple mechatronic system. To achieve this goal, our system (named “MEchatronic system for MOtor recovery after Stroke” (MEMOS)) has been designed with the aim of using mainly “off-the-shelf products” with only few parts simply manufactured with standard technology, when commercial parts were not available. Moreover, the prototype has been developed taking into account the requirements related to the clinical applicability such as robustness and safety.The MEMOSsystem has been used during clinical trials with subjects affected by chronic hemiparesis (<6 months from the cerebrovascular accident). The results obtained during these experiments seem to showthat notwithstanding the simple mechatronic structure characterizing theMEMOSsystem, it is able to help chronic hemiparetics to reduce their level of impairment.Further clinical experiments with acute and chronic subjects will be carried out in order to confirm these preliminary findings. Moreover, experiments for tele-rehabilitation of patients will be also carried out.

Augmented reality as an aid in maxillofacial surgery: validation of a wearable system allowing maxillary repositioning.

AIM We present a newly designed, localiser-free, head-mounted system featuring augmented reality as an aid to maxillofacial bone surgery, and assess the potential utility of the device by conducting a feasibility study and validation. METHODS Our head-mounted wearable system facilitating augmented surgery was developed as a stand-alone, video-based, see-through device in which the visual features were adapted to facilitate maxillofacial bone surgery. We implement a strategy designed to present augmented reality information to the operating surgeon. LeFort1 osteotomy was chosen as the test procedure. The system is designed to exhibit virtual planning overlaying the details of a real patient. We implemented a method allowing performance of waferless, augmented-reality assisted bone repositioning. In vitro testing was conducted on a physical replica of a human skull, and the augmented reality system was used to perform LeFort1 maxillary repositioning. Surgical accuracy was measured with the aid of an optical navigation system that recorded the coordinates of three reference points (located in anterior, posterior right, and posterior left positions) on the repositioned maxilla. The outcomes were compared with those expected to be achievable in a three-dimensional environment. Data were derived using three levels of surgical planning, of increasing complexity, and for nine different operators with varying levels of surgical skill. RESULTS The mean error was 1.70 ± 0.51 mm. The axial errors were 0.89 ± 0.54 mm on the sagittal axis, 0.60 ± 0.20 mm on the frontal axis, and 1.06 ± 0.40 mm on the craniocaudal axis. The simplest plan was associated with a slightly lower mean error (1.58 ± 0.37 mm) compared with the more complex plans (medium: 1.82 ± 0.71 mm; difficult: 1.70 ± 0.45 mm). The mean error for the anterior reference point was lower (1.33 ± 0.58 mm) than those for both the posterior right (1.72 ± 0.24 mm) and posterior left points (2.05 ± 0.47 mm). No significant difference in terms of error was noticed among operators, despite variations in surgical experience. Feedback from surgeons was acceptable; all tests were completed within 15 min and the tool was considered to be both comfortable and usable in practice. CONCLUSION We used a new localiser-free, head-mounted, wearable, stereoscopic, video see-through display to develop a useful strategy affording surgeons access to augmented reality information. Our device appears to be accurate when used to assist in waferless maxillary repositioning. Our results suggest that the method can potentially be extended for use with many surgical procedures on the facial skeleton. Further, our positive results suggest that it would be appropriate to proceed to in vivo testing to assess surgical accuracy under real clinical conditions.

Electromagnetic navigation platform for endovascular surgery: how to develop sensorized catheters and guidewires.

Endovascular procedures are nowadays limited by difficulties arising from the use of 2D images and are associated with dangerous X‐ray exposure and the injection of nephrotoxic contrast medium.

ENDOCAS NAVIGATOR PLATFORM: A COMMON PLATFORM FOR COMPUTER AND ROBOTIC ASSISTANCE IN MINIMALLY INVASIVE SURGERY.

Computer‐assisted surgery (CAS) systems are currently used in only a few surgical specialties: ear, nose and throat (ENT), neurosurgery and orthopaedics. Almost all of these systems have been developed as dedicated platforms and work on rigid anatomical structures. The development of augmented reality systems for intra‐abdominal organs remains problematic because of the anatomical complexity of the human peritoneal cavity and especially because of the deformability of its organs. The aim of the present work was to develop and implement a highly modular platform (targeted for minimally invasive laparoscopic surgery) generally suitable for CAS, and to produce a prototype for demonstration of its potential clinical application and use in laparoscopic surgery.

Electromagnetic navigation system for endovascular surgery

Endovascular procedures are nowadays limited by difficulties arising from the use of 2D images and are associated with dangerous X‐ray exposure and the injection of nephrotoxic contrast medium.

Autostereoscopic Three-Dimensional Viewer Evaluation Through Comparison With Conventional Interfaces in Laparoscopic Surgery

In the near future, it is likely that 3-dimensional (3D) surgical endoscopes will replace current 2D imaging systems given the rapid spreading of stereoscopy in the consumer market. In this evaluation study, an emerging technology, the autostereoscopic monitor, is compared with the visualization systems mainly used in laparoscopic surgery: a binocular visor, technically equivalent from the viewer’s point of view to the da Vinci 3D console, and a standard 2D monitor. A total of 16 physicians with no experience in 3D interfaces performed 5 different tasks, and the execution time and accuracy of the tasks were evaluated. Moreover, subjective preferences were recorded to qualitatively evaluate the different technologies at the end of each trial. This study demonstrated that the autostereoscopic display is equally effective as the binocular visor for both low- and high-complexity tasks and that it guarantees better performance in terms of execution time than the standard 2D monitor. Moreover, an unconventional task, included to provide the same conditions to the surgeons regardless of their experience, was performed 22% faster when using the autostereoscopic monitor than the binocular visor. However, the final questionnaires demonstrated that 60% of participants preferred the user-friendliness of the binocular visor. These results are greatly heartening because autostereoscopic technology is still in its early stages and offers potential improvement. As a consequence, the authors expect that the increasing interest in autostereoscopy could improve its friendliness in the future and allow the technology to be widely accepted in surgery.

Ultrasound guided robotic biopsy using augmented reality and human-robot cooperative control

Ultrasound-guided biopsy is a proficient mininvasive approach for tumors staging but requires very long training and particular manual and 3D space perception abilities of the physician, for the planning of the needle trajectory and the execution of the procedure. In order to simplify this difficult task, we have developed an integrated system that provides the clinician two types of assistance: an augmented reality visualization allows accurate and easy planning of needle trajectory and target reaching verification; a robot arm with a six-degree-of-freedom force sensor allows the precise positioning of the needle holder and allows the clinician to adjust the planned trajectory (cooperative control) to overcome needle deflection and target motion. Preliminary tests have been executed on an ultrasound phantom showing high precision of the system in static conditions and the utility and usability of the cooperative control in simulated no-rigid conditions.

Augmented Reality System for Freehand Guide of Magnetic Endovascular Devices

Magnetic guide of endovascular devices or magnetized therapeutic microparticles to the specific target in the arterial tree is increasingly studied, since it could improve treatment efficacy and reduce side effects. Most proposed systems use external permanent magnets attached to robotic manipulators or magnetic resonance imaging (MRI) systems to guide internal carriers to the region of treatment. We aim to simplify this type of procedures, avoiding or reducing the need of robotic arms and MRI systems in the surgical scenario. On account of this we investigated the use of a wearable stereoscopic video see-through augmented reality system to show the hidden vessel to the surgeon; in this way, the surgeon is able to freely move the external magnet, following the showed path, to lead the endovascular magnetic device towards the desired position. In this preliminary study, we investigated the feasibility of such an approach trying to guide a magnetic capsule inside a vascular mannequin. The high rate of success and the positive evaluation provided by the operators represent a good starting point for further developments of the system.

Patient-specific ultrasound liver phantom: materials and fabrication method

PurposeAn anatomically realistic ultrasound liver phantom with tissue-specific distinct signal properties is needed for training of novices in diagnostic and interventional procedures. The main objective of this work was development and testing of a new durable liver ultrasound training phantom for use with a hybrid simulator.MethodsA liver ultrasound phantom was fabricated in four main phases: materials selection, segmentation of CT images and realization of 3D models, vessel and lesion realization, and final assembly with silicone casting. Silicone was used as basic material due to its durability and stability over time. Several additives were analyzed and mixed with the polymer to reproduce the echogenicity of three simulated soft tissue types: parenchyma, lesions, and veins.ResultsCysts and vessel trees appear anechoic in the B mode ultrasound images when realized with pure silicone. The liver parenchyma, hypoechoic, and hyperechoic lesions were realized with different concentrations of graphite and Vaseline oil to increase their relative echogenicity. These materials were successful for creation of an ultrasound liver phantom containing simulated blood vessels and lesions.ConclusionThe phantom reproduces the human liver morphology and provides vessels and lesions ultrasound images with recognizable differences in echogenicity. The speed of sound in the simulated materials is inaccurate, but the problem can be overcome via software adjustment in a hybrid simulator.

Configurable Software Framework for 2D/3D Video See-Through Displays in Medical Applications

Augmented Reality (AR) has already proven its worth in various applications in the medical domain. However, most of the solutions proposed were bound to specific hardware or software configurations, and/or their application was limited to specific cases, thus lacking in flexibility. In this paper, we present a software framework suitable for AR video see-through systems conceived for medical applications: our solution allows merging of real world images grabbed by one or more external cameras with computer-generated sceneries coregistered to the acquired images. The software framework is highly configurable and extensible thanks to the employment of two text configuration files that make it suitable for many typologies of potential applications. The proposed solution can be easily adapted to functioning with different tracking and AR visualization modalities. The versatility of the software for video see-through AR applications was already tested on various medical applications, in conjunction with head-mounted displays or with external spatial displays.