Development and Evaluation of a Flexible PVDF-Based Balloon Sensor for Detecting Mechanical Forces at Key Esophageal Nodes in Esophageal Motility Disorders

Abstract

Prevailing methods for esophageal motility assessments, such as perfusion manometry and probe-based function imaging, frequently overlook the intricate stress fields acting on the liquid-filled balloons at the forefront of the probing device within the esophageal lumen. To bridge this knowledge gap, we innovatively devised an infusible flexible balloon catheter, equipped with a quartet of PVDF piezoelectric sensors. This design, working in concert with a bespoke local key-node analytical algorithm and a sensor array state analysis model, seeks to shed new light on the dynamic mechanical characteristics at pivotal esophageal locales. To further this endeavor, we pioneered a singular closed balloon system and a complementary signal acquisition and processing system that employs a homogeneously distributed PVDF piezoelectric sensor array for the real-time monitoring of dynamic mechanical nuances in the esophageal segment. An advanced analytical model was established to scrutinize the coupled physical fields under varying degrees of balloon inflation, thereby facilitating a thorough dynamic stress examination of local esophageal nodes. Our rigorous execution of static, dynamic, and simulated swallowing experiments robustly substantiated the viability of our design, the logical coherence of our esophageal key-point stress analytical algorithm, and the potential clinical utility of a flexible esophageal key-node stress detection balloon probe outfitted with a PVDF array. This study offers a fresh lens through which esophageal motility testing can be viewed and improved upon.

Keywords: advanced infusion-compatible balloon catheter; esophageal biomechanical dynamics; esophageal stress analysis; polyvinylidene fluoride (PVDF) piezoelectric sensor matrix.

Figure 1

Flexible balloon structure at key points of esophagus based on PVDF: (a) schematic diagram of the balloon structure; (b) working schematic of the sensor system; and (c) PVDF piezoelectric film sensor on the catheter.

Figure 1

Flexible balloon structure at key points of esophagus based on PVDF: (a) schematic diagram of the balloon structure; (b) working schematic of the sensor system; and (c) PVDF piezoelectric film sensor on the catheter.

Figure 2

Circuit architecture of esophagus dynamic detection system based on piezoelectric sensor: (a) test circuit system architecture and (b) sensing device architecture.

Figure 3

Sensor performance test platform: (a) overall structure of the experimental platform and (b) static characteristic test procedure of the sensor balloon.

Figure 4

Schematic of dynamic pressure measurement of key nodes: (a) key node dynamic pressure measurement process and (b) single position sinusoidal load curve.

Figure 5

Esophageal peristalsis function curve simulated during swallowing.

Figure 6

Sensor theoretical output curve.

Figure 7

Pressure sensor array static output curve.

Figure 8

Balloon state under different filling degrees (k, %, the amount of fluid filled into the vacuum anhydrous balloon as a percentage of the balloon volume when filled with liquid): (a) k = 0; (b) k = 25; (c) k = 50; (d) k = 75; and (e) k = 100.

Figure 9

Dynamic output characteristic curve of partition with 0% filling degree.

Figure 10

Time series dynamic output curve(k = 0).

Figure 11

Time series dynamic output curve (k = 100).

Figure 12

Time series dynamic output curve (k = 25).

Figure 13

Time series dynamic output curve (k = 50).

Figure 14

Time–position–pressure curve of the sensor array (k = 75).

Figure 15

Output curve of sensor array under peristaltic waves simulating the swallowing process (k = 75).