Patients have little appetite for going under the knife and manufacturers are always hungry for a challenge. Minimally invasive procedures satisfy patients' desire for a quick recovery, and manufacturers are responding to the call for the devices needed to conduct those procedures. Patients can now look forward to shorter hospital stays and recovery times, and manufacturers can keep their teeth sharp by keeping up with--or staying ahead of--the demand. To help meet the demand, suppliers are standing ready with new techniques and ideas for minimally invasive surgery (MIS) device applications.

Because MIS is performed without making a major incision or opening, patients experience less trauma, which results in shorter hospital stays and reduced recovery times. The quicker recovery time for patients translates into cost-effectiveness for hospitals, which is helping to drive MIS device demand. The global market for MIS devices was worth an estimated $12 billion in 2005 and is expected to climb to $18.5 billion by 2011, according to a report from market analysis firm BCC Research. The report--which attributes 60% of the global MIS market to the United States--also says that surgical devices are the largest product segment of the U.S. MIS market, accounting for about 69%, followed by monitoring and visualization systems with an 11% market share.

"Minimally invasive surgical techniques are being employed across various specialties; however, there is still scope for their expansion," according to market research firm Frost & Sullivan's report on MIS devices in European markets. "Companies can focus on increasing the application of such procedures within specialties or in new areas where such procedures have not yet been performed," it states.

As MIS procedures advance, the demand for smaller, smarter tools and devices increases. "The minimally invasive surgery sector is traditionally regarded as having a large appetite for new innovations and, despite the cost pressures within the market, that appetite is still apparent," says Maura Leahy, product manager at Creganna (Galway, Ireland; www.creganna.com), which specializes in metals, extrusions, and molding for catheter shafts and specialty needles, components, and subassemblies.

Developing a Taste for Something New

Minimally invasive surgery isn't only creating demand for new tools, it's causing members of industry to reevaluate how some current tools are used. While OEMs may be excited about new device ideas for the growing MIS market--and eager to meet demand--they seem to be more tentative about integrating new techniques that could improve their processes. "Compared to the electronics industry, MIS device manufacturing is still very manual and uses lots of old technology," says Peter Gottschlich, CEO of Automation GT (Escondido, CA; www.automationgt.com), which designs and builds equipment to aid assembly and testing of minimally invasive devices (MIDs).

Gottschlich cites the burden of FDA approval and validation as one cause for the slow adoption of newer or more-automated technologies in MID manufacturing. "The nature of the product also makes it difficult to automate in the first place," he adds. "Production requires a lot of manual operations and efficiency is low, making it costly to manufacture overall," Gottschlich says. "Since competition is low, and the cost is eventually pushed down to people and companies paying health insurance, motivation to cut manufacturing cost is low."

Because semiconductor and chip manufacturers use the same high-precision, highly automated processes to serve a number of industries, production technology has been pushed to reach rates of testing components to about 17 parts per second. "This is a different world compared to building a catheter using lots of manual labor," Gottschlich says. "The quantity of product needed [for MIS applications] is completely different, which makes it difficult for a catheter manufacturer to justify high-tech expenses in the first place." Another difference Gottschlich points out is that MID manufacturers are mainly focused on designing the products, whereas the electronics industry considers automation and low-cost manufacturing processes in addition to product functionality.

This rationale is causing MID manufacturers to hesitate before integrating new processes. For example, Automation GT offers a laser catheter bonder that it claims is much better than adhesive bonding. But Gottschlich says customers seem to be afraid to step outside their comfort zones and try different processes. Laser bonding melts both materials that it is bonding with heat. The company says that this method is more reliable than using adhesives, which can have inconsistent viscosities and adhesion rates, and can drip during application.

Building Devices One Microlayer at a Time

The growing trend in hospitals to perform less-invasive surgeries with smaller and fewer incisions, and, in the case of natural-orifice translumenal endoscopic surgery (NOTES), internal incisions only, piqued the interest of Microfabrica (Van Nuys, CA; www.microfabrica.com). "There is a need for smaller and more complex, sophisticated, and functional instruments," says Adam Cohen, Microfabrica's CTO and EVP of technology. "Simultaneously, there is growing pressure to reduce the cost without compromising the quality of medical care."

The company believes that EFAB meets these needs. Originally developed for MEMS applications, EFAB manufacturing technology produces small, precision metal parts and mechanisms by forming and stacking a set of thin metal layers, similar to some rapid prototyping technologies used to produce macro-scale models. However, EFAB can be used to produce functional metal devices or components with micron-scale features. In addition to making miniaturized surgical instruments, EFAB building blocks can be used to make medical devices for atherectomy, thrombectomy, drug-delivery, distal-protection, and tissue-approximation applications. EFAB also can be used for advanced guidewire and coil-delivery device applications.

Using the EFAB process can also reduce production costs by eliminating assembly steps, according to the company. For example, one customer brought a 1-mm-diam interventional device to Microfabrica that it had been producing through machining, fine blanking, and then assembling seven parts under a microscope. "We expect to reduce the cost of goods sold on this device by a factor of five or more, in part by fabricating all seven pieces as a single mechanism and avoiding assembly," says Cohen.

The high cost of producing complex small parts and then assembling them into devices can be dramatically reduced by using EFAB to monolithically fabricate sophisticated mechanisms with multiple independently, moving parts, according to Cohen. Compared with 3-D processes like machining or metal-injection molding, EFAB offers OEMs the ability to manufacture products that don't require assembly, and have greater complexity and higher accuracy at a lower cost, Cohen says. And, compared with 2-D processes such as laser or photochemical machining and stamping, EFAB can produce straighter sidewalls and smaller features, he adds. The technology does, however, have limitations. Parts currently need to have at least one dimension no larger than 1 mm, though the company is also working to increase this for future applications.

Though it currently uses Valloy-120 for medical devices, the company is also developing new materials to increase EFAB's capabilities. Valloy-120 has properties similar to stainless steel and has passed biocompatibility tests for 24-hour exposure to tissue and circulating blood, but is not believed to be implantable.

Understanding Material Limitations

One of the biggest challenges in terms of MIS device manufacturing that Martech Medical (Harleysville, PA; www.martechmedical.com) is encountering is that device designers aren't always aware of the limitations of the materials and processes available, according to Frank DeBartola, director of sales and marketing. The company provides tool design and production services to medical device manufacturers.

For instance, in the vascular-access catheter market, the peripherally inserted central catheter (PICC) has, for decades, been a silicone catheter that was inserted for the purpose of delivering medication and performing blood withdrawals, says DeBartola. This one-time simple catheter is now being used for long-term chemotherapy delivery, in many cases replacing surgically implanted ports.

"We are finding more companies coming to us to provide them with PICCs made of a multitude of urethanes that must be able to withstand extremely high pressure ratings while maintaining a small bore [and] tight tolerances," says DeBartola.

The urethane catheters must also have reverse taper extrusion, be easy to insert, and be able to stay implanted for much longer periods of time. But the reverse taper extrusion is difficult to achieve while maintaining tight tolerances. "The [urethane] material is more difficult to extrude but it allows for greater strength," says DeBartola. "It is easier to make something stronger by making it bigger; the challenge is making it smaller but stronger."

Creganna is also familiar with material woes associated with emerging MIS applications, especially in terms of cost savings. "A lot of product development teams would like to explore the potential benefits of using 'smart' alloy nitinol in their minimally invasive delivery system but the cost of the material was prohibitive," Leahy says. In general, when nitinol is used in a delivery system, it is only used in the tip or distal end of the catheter, according to the company. To expand the potential applications for the material, Creganna's innovation team commercialized a hybrid nitinol and stainless-steel welding solution for tubular components that it named Fusion Technology. "[The material] lowers overall product costs and makes nitinol a viable design alternative," she says.

Forging Ahead

Leahy says that the demand for micro-sized medical devices is driven by advances in MIS to treat areas of the human body that are hard to access, let alone maneuver within, such as the neurovasculature. In response to this need, Creganna is developing more process functionality around micro solutions with very tight tolerances. One example is the company's Microflex product, a stainless-steel tube that can be manufactured with an OD as small as 0.008 in. This single-piece microtube is offered as a cost-effective alternative to multipiece microtube assemblies for devices used for small-vasculature navigation.

Microflex was developed as a result of extensive research in the field of MIS conducted by Creganna's innovation team. Dedicated to developing new technologies for Creganna's customers, the team actively monitors trends in the market. The industry is populated with--and benefiting from--products that have been the result of efforts made by research teams. Even EFAB started out as an idea at the University of Southern California (Los Angeles; www.usc.edu).

While developing new products for companies, research teams can also help companies keep up to date on emerging technologies. From its innovation team, Creganna has yielded information that will help set the company's course for the future. Leahy points out that emerging market segments are exhibiting a pattern of demand for delivery systems outside of the vascular system as companies seek out the least invasive method to treat a patient. "Clinical developments such as orthobiologic treatments and NOTES seem to be gaining momentum," she says. "Innovators in such fields are keen to incorporate the most advanced technologies from the portfolio of solutions for vascular delivery into their products."

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