Ali Awaz, Sakes Aimee, Arkenbout Ewout A, Henselmans Paul, van Starkenburg Remi, Szili-Torok Tamas, Breedveld Paul
BioMechanical Engineering, Delft University of Technology (TU Delft), Delft, The Netherlands.
DEMO, Delft University of Technology (TU Delft), Delft, The Netherlands.
Proc Inst Mech Eng H. 2019 Dec;233(12):1207-1218. doi: 10.1177/0954411919877709. Epub 2019 Oct 3.
In recent years, steerable catheters have been developed to combat the effects of the dynamic cardiac environment. Mechanically actuated steerable catheters appear the most in the clinical setting; however, they are bound to a number of mechanical limitations. The aim of this research is to gain insight in these limitations and use this information to develop a new prototype of a catheter with increased steerability. The main limitations in mechanically steerable catheters are identified and analysed, after which requirements and solutions are defined to design a multi-steerable catheter. Finally, a prototype is built and a proof-of-concept test is carried out to analyse the steering functions. The mechanical analysis results in the identification of five limitations: (1) low torsion, (2) shaft shortening, (3) high unpredictable friction, (4) coupled tip-shaft movements, and (5) complex cardiac environment. Solutions are found to each of the limitations and result in the design of a novel multi-steerable catheter with four degrees of freedom. A prototype is developed which allows the dual-segmented tip to be steered over multiple planes and in multiple directions, allowing a range of complex motions including S-shaped curves and circular movements. A detailed analysis of limitations underlying mechanically steerable catheters has led to a new design for a multi-steerable catheter for complex cardiac interventions. The four integrated degrees of freedom provide a high variability of tip directions, and repetition of the bending angle is relatively simple and reliable. The ability to steer inside the heart with a variety of complex shaped curves may potentially change conventional approaches in interventional cardiology towards more patient-specific and lower complexity procedures. Future directions are headed towards further design optimizations and the experimental validation of the prototype.
近年来，可操纵导管已被开发出来以应对动态心脏环境的影响。机械驱动的可操纵导管在临床环境中出现得最多；然而，它们受到一些机械限制。本研究的目的是深入了解这些限制，并利用这些信息开发一种具有更高可操纵性的新型导管原型。确定并分析了机械可操纵导管的主要限制，之后定义了设计多可操纵导管的要求和解决方案。最后，制造了一个原型并进行了概念验证测试以分析其转向功能。机械分析确定了五个限制：（1）低扭转，（2）轴缩短，（3）高不可预测摩擦，（4）尖端-轴运动耦合，以及（5）复杂的心脏环境。针对每个限制都找到了解决方案，并由此设计出一种具有四个自由度的新型多可操纵导管。开发了一个原型，该原型允许双节段尖端在多个平面和多个方向上进行操纵，实现一系列复杂运动，包括S形曲线和圆周运动。对机械可操纵导管潜在限制的详细分析促成了一种用于复杂心脏介入的多可操纵导管的新设计。四个集成的自由度提供了高度可变的尖端方向，并且弯曲角度的重复相对简单且可靠。能够在心脏内部以各种复杂形状的曲线进行操纵可能会潜在地改变介入心脏病学中的传统方法，朝着更针对患者和复杂度更低的程序发展。未来的方向是进一步优化设计并对原型进行实验验证。
