Active Lubrication of Transluminal Medical Instruments

Transluminal minimally invasive surgery uses natural orifices and small incisions to access internal anatomical structures, promoting quicker recovery and reduced morbidity. However, navigating instruments such as catheters and endoscopes through anatomical pathways creates frictional interactions with luminal walls, risking complications such as perforation, poor haptic feedback, and instrument buckling. This paper presents an active lubrication sheath that controls friction on demand through discrete friction control modules distributed along its shaft. These modules employ ultrasonic vibrations at the instrument surface to generate a pressurized fluid layer at the contact interface, lubricating the interface and thereby reducing friction. We implemented these modules in a prototype catheter, which we validated under dry and liquid-lubricated conditions, across rigid and soft interfaces, and along varied anatomical curvatures. In a cardiac catheterization use case, active lubrication reduced friction by up to 42% on ex vivo porcine aorta tissue hydrated with phosphate-buffered saline, and thermal imaging measured an average temperature rise of 6.2 degrees Celsius at the module-tissue interface due to vibration, confirming its potential thermal safety. In a catheter insertion demonstration, active lubrication reduced friction-induced buckling and enabled smoother advancement through the lumen, further showcasing its potential impact. By minimizing injury risk and enhancing procedural stability, active lubrication can drastically enhance the safety and efficacy of transluminal interventions.