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Views: 0 Author: Bova Publish Time: 2026-06-17 Origin: Site
In endoscopic retrograde cholangiopancreatography (ERCP) for bile duct stone removal, the three-lumen variable diameter catheter, as a core component of the stone removal balloon, directly affects the insertion success rate, the surgical market, and patient prognosis. Standardized catheters are insufficient to cover complex biliary anatomy and the needs of special cases, making customized three-lumen variable diameter catheters an important development direction in the field of digestive endoscopy.
The three-lumen variable-diameter catheter features three independent channels, each with its own function and without interference: the first lumen is the balloon inflation/deflation channel, precisely controlling balloon expansion and contraction for stone retrieval and release; the second lumen is the guidewire channel, ensuring precise catheter advancement along the guidewire to the target bile duct segment; and the third lumen is the contrast agent injection channel, allowing for simultaneous intraoperative injection of contrast agent to provide real-time visualization of the bile duct morphology and stone location without the need for repeated instrument changes. This independent three-lumen design avoids the drawbacks of frequent manipulation and cutting required with single-lumen and double-lumen catheters, significantly shortening the operation time.
The variable-diameter catheter features a tapered structure with a thicker proximal end and a gradually tapering distal end. The larger diameter at the proximal end ensures the rigidity of the catheter and facilitates its movement, making it easier for the surgeon to manipulate. The narrower outer diameter at the distal end improves passage through the duodenal papilla and strictures, reducing the difficulty of insertion and the risk of tissue damage. Compared to equal-diameter catheters, the tapering design can increase insertion speed by more than 30%, making it particularly suitable for complex cases such as papillary stenosis and tortuous bile ducts, effectively reducing the incidence of postoperative complications such as pancreatitis and bleeding.
Customization allows for adjustments to the interface distribution, inner diameter ratio, and wall thickness parameters of the three lumens based on clinical needs. While conventional three-lumen catheters typically have a centrally located guidewire, customized solutions can feature an offset design for the contrast chamber, optimizing the contrast agent injection angle. For large stone removal scenarios, the balloon's inner diameter can be increased to improve inflation speed and balloon pressure resistance. Inner diameter tolerances can be controlled within ±0.015mm, ensuring stable function of each lumen and preventing cross-contamination.
The diameter gradient is a core customized indicator, including the starting position of the diameter change, the taper length, and the range of diameter variation. For intrahepatic bile duct stone removal, a long, gradually tapering structure can be designed to ensure smooth passage of the catheter through secondary and tertiary single tubes; for large common bile duct stones, a short, steeply tapering design can be used to balance distal passageability and proximal support. In terms of materials, medical-grade polymers such as Pebax, TPU, and PA can be used. Combining different hardness grades can achieve a "firm proximal, soft distal" hardness gradient, balancing delivery and flexibility.
The location, number, and method of the imaging lines can be customized. Co-extruded imaging strips or interchangeable imaging markers are used to ensure that the catheter position and balloon boundary are clearly identifiable under X-ray. The balloon portion can be customized in diameter (9mm-16mm, multiple options available), length, and material to achieve a seamless welding fit between the catheter and balloon, avoiding leakage risks and meeting the stone removal requirements of different sizes.
Custom-made three-lumen variable-diameter catheters rely on precision extrusion and post-processing techniques. The extrusion process requires specialized variable-diameter dies and precise tie-rod control technology to achieve a smooth, continuous transition in diameter, avoiding uneven wall thickness and internal deformation. Post-processing encompasses tip forming, drilling, balloon welding, and graduation printing, among which variable-diameter welding and tip rounding are the most challenging aspects, directly impacting catheter safety.
Compliant production must be completed in a Class 10,000 cleanroom, certified by the ISO 13485 quality management system. Raw materials must meet medical-grade biocompatibility standards, and the entire process must be traceable to ensure the finished product meets medical device registration requirements.
When selecting a supplier, three key capabilities should be considered: first, extrusion R&D capabilities, including the availability of multi-cavity variable-diameter extrusion production lines and mature process experience, as well as the ability to provide sample testing; second, post-processing support capabilities, such as the ability to complete all structural processes including tip making, welding, and coating in a one-stop manner; and third, a quality control system, including the availability of cleanroom facilities and comprehensive testing capabilities, and the ability to provide verification reports on biocompatibility, pressure resistance, and leakage.
Kunshan Bova Plastics provides full-process support from drawing evaluation and process optimization to small-batch pilot production, helping medical device manufacturers quickly launch differentiated ERCP stone retrieval products and enhance their clinical competitiveness.
