Contact force sensors in minimally invasive catheters: current and future applications

ABSTRACT

Introduction

Advances in catheter design for minimally invasive surgery have brought about the incorporation of contact force (CF) sensors in catheters. Two main approaches to achieve CF sensing at the catheter end-effector consist of fiber optic or magnetic solutions. CF sensing feedback can be used to assist in ablation procedures, mapping cardiac regions, identifying tissue characteristics, and enhancing robotic catheter control.

Areas Covered

This review covers the technological and clinical aspects of CFS in catheters. Contact force and force-time integral thresholds for ablation procedures, procedural complications, and electroanatomical mapping strategies are discussed. Future applications of improving catheter control, minimizing complications, and enhancing mapping techniques through CF are examined.

Expert Opinion

Fiber optic CF catheters may be more desirable compared to magnetic modalities due to the lower cost, compactness, and higher accuracy. In ablation procedures, complications due to higher ablation duration, power, contact force, and force time can be reduced through practical experience and informed training for catheter operators. Future prospects consist of the incorporation of CF sensors with remote catheter systems to assist in catheter control. We propose that CF can also be used in machine learning decision-making algorithms to prevent complications or improve tissue characterization.

KEYWORDS:

• Cardiac ablation
• catheters
• force sensors
• minimally invasive surgery
• electroanatomical mapping
• robot control

Article Highlights

• Contact force (CF) sensors at the end-effector of minimally invasive catheters have been developed by means of A) embedded magnets and magnetic transmitters or B) intensity-modulated, phase-modulated or wavelength-modulated optical fibers.

• The application of CF has been particularly beneficial in cardiac ablation procedures where CF or force-time integral (FTI) threshold values have been established to ensure efficacy, prevent recurrence, and minimize complications.

• Typical CF and FTI values range from 10 to 40 g and 230–420 g·s, respectively, depending on the ablated region, power and duration. High-power short-duration ablations tend to be performed at lower CF ranges (10–20 g).

• High-quality electroanatomic three-dimensional mapping or tissue characterization of intracardiac regions require minimal CF cut-off values of >5 to 9 g.

• Future applications include the incorporation of force feedback into robotic catheter systems where automated tasks can be developed, such as maintaining contact of the catheter end-effector with the tissue wall within a given CF range. Decision-making algorithms can also use CF and FTI as input features to predict potential incidences of complications.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was funded by the National Natural Science Foundation of China (grant no. 81950410635)