Changes in Medical Procedures Fuel Demand for Increasingly Narrow Tubing

Specializing in the manufacture of polyimides but incorporating other thermoplastics into product design, Microlumen is diversifying its product line and services to better service its medical customers.

You know, I wouldn't be surprised if a manufacturer asked me to fabricate tubing with an outer diameter that is smaller than the inner diameter, an exasperated extruder once told me. A slight exaggeration to be sure, but it's undeniable that makers of medical-grade tubing are being asked to meet challenging demands on a daily basis, from finding ways to accelerate product development to adding features to a product while reducing its overall size.

The drive to miniaturize

The medical device industry is a harsh taskmaster, acknowledges Diane Fukuda, president of Microspec Corp. (Peterborough, NH, USA), which produces custom tubing from a variety of thermoplastic elastomers and engineering plastics. "Our customers may want greater functionality and/or variable dimensions in a single extruded segment," she notes. Material selection, especially in regards to PVC alternatives, is also a big-ticket item on their checklists. And, of course, there is the constant drumbeat to make it smaller.

The drive to miniaturize "is a consequence of minimally invasive procedures," explains Fukuda, "but it is also a result of a growing awareness of the need for appropriately sized pediatric products." In many cases, medical device manufacturers traditionally have opted to let hospital personnel improvise ways to use existing devices on children rather than run expensive pediatric studies. That may be changing, and tubing suppliers are happy to help. Microspec is showing the way by redoubling its R&D efforts, says Fukuda.

"I was brought on board because company founder Tim Steele chose to rededicate more of his time and resources to R&D," says Fukuda. She applauds him for relinquishing control of the company's day-to-day operations. Many founders of successful companies have progressively taken on administrative duties. They can no longer find their way out of those responsibilities and devote themselves to what made the company successful in the first place, she explains. Steele currently is happily ensconced in a new facility with a dedicated R&D area that the company recently completed.

Increasing functionality while shrinking product size is also a commonly heard refrain at ANSAmed (Abbeytown, Co. Roscommon, Ireland). "Customers want us to fit more lumens into a smaller space, or at least within a space that is no larger than an existing product," says Richard Gribbons, business development manager. To further push the boundaries of MIS tubing, the company recently introduced nanobore extrusion technology. This technique produces tubing with inner diameters as small as 0.2 mm and walls as thin as 0.04 mm.

ANSAmed devotes considerable resources to developing specialist tubing, for which there is great demand. "Our customers are looking for complex and robust products," says Gribbons. The company provides braided tubing with inner diameters measuring 0.4 to 4.5 mm and outer diameters from 2 to 24 French. Regular diamond, half load, and variable-pick-count braid configurations are available.

Meanwhile, customers of Microlumen Inc. (Tampa, FL, USA) are clamoring for ways to accelerate their products' speed to market. "I hear it daily," says Krissi Heard, technical sales. The company has responded by doing lots of added value work. For example, the firm routinely laser-drills holes into tubing and adds marker bands. "By offering these services we can lower costs and even speed approvals, because the device manufacturer is dealing with fewer suppliers," notes Heard. "We have partnerships with a few qualified subcontractors to do the things we don't."

Microlumen is a materials oriented company, manufacturing polyimides and incorporating other thermoplastics into the design, says Heard. "But we are diversifying our product line," she notes, "and we have started to diversify our services by providing some assembly work, for example." As for technical breakthroughs, they are often a byproduct of customer demand. "They often come to us with a device that's in development and tell us: Here is what I need the tubing to do. That's when we get to work," says Heard.

Stent solutions

While smaller diameters and thinner walls are also a focus for makers of metal tubing, material considerations are getting a great deal of attention at Minitubes (Grenoble, France). The firm is currently working hard to develop cobalt chromium–based devices to leverage the material's biocompatibility and strength.

The company's product portfolio includes a cobalt chromium, molybdenum and nickel alloy, which features ductility and mechanized strength properties, that has a unique combination of tensile strength, ductility, toughness, and corrosion resistance.

Because it is both strong and lightweight, cobalt chromium has become a popular option for the production of stents. According to Minitubes, cobalt chromium stents have a better mechanized strength-to-weight ratio than their stainless-steel counterparts yet offer the same ductility.

Stephen McNamara contributed to this article.