A self calibrating, magnetic sensor approach accurately positions an aortic damage control stent in a porcine model

Dahlia M Kenawy; Yifan Zhang; Moataz Elsisy; Mahmoud Abdel-Rasoul; Youngjae Chun; William C Clark; Bryan W Tillman

doi:10.1136/tsaco-2023-001220

A self calibrating, magnetic sensor approach accurately positions an aortic damage control stent in a porcine model

Trauma Surg Acute Care Open. 2023 Dec 8;8(1):e001220. doi: 10.1136/tsaco-2023-001220. eCollection 2023.

Authors

Dahlia M Kenawy¹, Yifan Zhang², Moataz Elsisy^{2

3}, Mahmoud Abdel-Rasoul⁴, Youngjae Chun², William C Clark², Bryan W Tillman¹

Affiliations

¹ Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
² Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
³ Mechanical Design and Production Department, Cairo University Faculty of Engineering, Cairo, Egypt.
⁴ Biomedical Informatics, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.

Abstract

Objectives: Non-compressible torso hemorrhage remains a high mortality injury, with difficulty mobilizing resources before exsanguination. Previous studies reported on a retrievable stent graft for damage control and morphometric algorithms for rapid placement, yet fluoroscopy is impractical for the austere environment. We hypothesized that magnetic sensors could be used to position stents relative to an external magnet placed on an anatomic landmark, whereas an electromagnet would allow self-calibration to account for environmental noise.

Methods: A magnetic sensor alone (MSA) and with integrated stent (MSIS) were examined in a porcine model under anesthesia. A target electromagnet was placed on the xiphoid process (position 0 cm). Sensors were placed in the aorta and measurements obtained at positions 0 cm, +4 cm, and +12 cm from the magnet and compared with fluoroscopy. Sensors were examined under conditions of tachycardia/hypertension, hypotension, vibration, and metal shrapnel to simulate environmental factors that might impact accuracy. General linear models compared mean differences between fluoroscopy and sensor readings.

Results: Both sensors were compatible with a 10 French catheter system and provided real-time assessment of the distance between the sensor and magnetic target in centimeters. Mean differences between fluoroscopy and both magnetic sensor readings demonstrated accuracy within ±0.5 cm for all but one condition at 0 cm and +4 cm, whereas accuracy decreased at +12 cm from the target. Using the control as a reference, there was no significant difference in mean differences between fluoroscopy and both MSA or MSIS readings at 0 cm and +4 cm for all conditions. The system retained effectiveness if the target was overshot.

Conclusion: Magnetic sensors achieved the highest accuracy as sensors approached the target. Oscillation of the electromagnet on and off effectively accounts for environmental noise.This approach is promising for rapid and accurate placement of damage control retrievable stent grafts when fluoroscopy is impractical.

Level of evidence: Not applicable.

Keywords: War-Related Injuries; aortic rupture; endovascular procedures; stents.

Abstract

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