Aldo Alberti

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.

Simultaneous tracking of catheters and guidewires: comparison to standard fluoroscopic guidance for arterial cannulation.

OBJECTIVES The purpose of this in vitro study was to clinically assess the feasibility of a three-dimensional (3D) electromagnetic (EM) navigator, including sensorized catheters and guidewires, to determine any reduction in radiation dose and contrast medium injection. METHODS The study was performed using a navigator prototype developed at the EndoCAS center. The system includes catheters and guidewires simultaneously tracked with an EM localizer (Aurora, Northern Digital, Waterloo, Canada). Tests were performed on a commercial abdominal aortic aneurysm model. Fifteen operators were asked to cannulate renal arteries using the conventional fluoroscopic guidance and the EM navigator without fluoroscopic support. Each trial was video-recorded and analyzed for timing and success of completing the cannulation task by two blinded and independent observers. Performances were also qualitatively evaluated using the Imperial College Endovascular Cannulation Scoring Tool (IC3ST). Moreover, a questionnaire was administered to participants to evaluate the navigator potentialities. RESULTS Quantitative analysis results show no significant difference between the fluoroscopic and EM guidance regarding the total procedure time (median 2.36 minutes [interquartile range {IQR} = 1.26-4.7) vs. 2.95 min [IQR = 1.35-5.38], respectively; p = .93); number of total hits with catheter/guidewire tip to vessels wall (median 5.50 [IQR = 2.00-10.00] vs. 3.50 [IQR = 2.50-7.00], respectively; p = .65); and number of attempts at cannulation (median 4.0 [IQR = 2.00-5.00] vs. 4.0 [IQR = 2.00-5.00], respectively; p = .72]. Moreover, there was no significant difference between the IC3ST score obtained using the EM navigator and the traditional method (average 22.37 [STD = 7.95] vs. 21.58 [STD = 6.86]; p = .92). Finally, questionnaire results indicate a general agreement concerning the navigator usefulness, which clearly shows the positions of instruments inside the 3D model of the patients anatomy. Participants also agreed that the navigator can reduce the amount of contrast media delivered to the patient, as well as fluoroscopy time. CONCLUSIONS This work provides proof of concept that simultaneous EM navigation of guidewires and catheters is feasible without the use of live fluoroscopic images.

Electromagnetic Guided In-Situ Laser Fenestration of Endovascular Stent-Graft: Endovascular Tools Sensorization Strategy and Preliminary Laser Testing

The in-situ endograft fenestration, a possible surgical option for the minimally invasive treatment of aneurysms with unfavorable anatomy, is today limited by difficulties in targeting the fenestration site and by the lack of a safe method to perforate the graft. In this work we suggest the use of: a 3D electromagnetic (EM) navigator, to accurately guide the endovascular instruments to the target, and a laser system, to selectively perforate the graft. More particularly we propose to integrate a laser fiber into a sensorized guidewire and we describe an EM sensorization strategy to accurately guide the laser tool. Finally we preliminary explore different laser irradiation conditions to achieve a successful endograft fenestration and we verify that the heating generated by the laser doesn’t damage the EM coils.

Using of 3D virtual reality electromagnetic navigation for challenging cannulation in FEVAR procedure

Virtual Reality (VR) is promising not just for the game and entertainment industry, but also for the medical and surgical fields, to develop simulation systems and navigation tools for the intra-operative assistance. Electromagnetic (EM) tracking technology is today widely proposed in the context of computer-assisted medical interventions.

Design of a sensorized guiding catheter for in situ laser fenestration of endovascular stent

Abstract Purpose: The in situ fenestration of a standard endograft is currently limited by difficulties in targeting the fenestration site under fluoroscopic control and by the lack of a safe method to perforate the graft. Evidence in the literature suggests the use of a 3 D electromagnetic navigator to accurately guide the endovascular instruments to the target and a laser to selectively perforate the graft. The aim of this work is to provide design guidelines to develop a sensorized catheter to guide the laser tool to the fenestration site and conduct preliminary testing of the feasibility of the proposed solution. Matherials and methods: Different catheter designs were delineated starting from engineering considerations, then prototypes were preliminarily tested to collect surgeon opinions and to steer the design process toward the preferred solution reported by the user. Finally, mechanical simulations were performed with CathCAD, a design software system for the development of composite tubing for endovascular catheters. Results: Based on surgeon feedback, a 9-French steerable catheter with a stabilization system was designed. CathCAD simulations allowed us to define the construction parameters (e.g., materials and geometric constrains) for the fabrication of composite tubes with mechanical properties (flexural, axial, and torsional rigidities) compatible with target values in the literature for guiding catheters. Conclusion: The presented results preliminarily demonstrate the clinical reasonability and feasibility of the designed tool in terms of mechanical properties. Further mechanical tests and extensive in vitro clinical trials are required prior to animal testing.