For patients suffering from severe asthma, the inability to properly manage symptoms using drug-based therapies such as inhaled corticosteroids (ICS) and long-acting beta-agonists (LABAs) may take the wind right out of their sails. Aiming to improve patients' quality of life while reducing the disease's economic burden on the healthcare system, Asthmatx (Sunnyvale, CA), which was acquired by Boston Scientific, has developed what it claims is the first nondrug procedure designed to treat severe persistent asthma in adults whose symptoms are not effectively controlled using traditional therapies.
Dating back to the late 1990s, the initial concept for Boston Scientific's Alair Bronchial Thermoplasty system emerged from the identification of a distinct, underserved patient population. "There are patients 18 and older with severe asthma that are on maximum medication, and they still can't control their asthma very well," explains Tim Dalbec, manager of R&D at Boston Scientific. "That's the population that we've focused on. However, the system's not meant to replace medications; it's to be used as a complement to medication to help keep symptoms under control."
Consisting of a catheter and a radiofrequency (RF) controller, the Alair system delivers the company's therapy, dubbed Bronchial Thermoplasty, during a minimally invasive, outpatient bronchoscopic procedure. The catheter is first inserted into the patient's lungs through a bronchoscope and positioned to contact the airway wall. Next, the catheter precisely delivers temperature-controlled thermal energy generated by the RF controller directly to the lining of the airway wall. Performed during three separate procedures that target three different areas of the lungs, Bronchial Thermoplasty serves to reduce excessive airway smooth muscle within the airway wall. This approach, according to Boston Scientific, is intended to decrease airway constriction and, in turn, reduce the frequency of asthma attacks.
Obtaining this level of functionality and design was the result of many years and many design iterations, however. Early on in the process, for example, the Boston Scientific team had to figure out how to overcome frictional issues that hindered catheter movement through the bronchoscope and prevented the device from deploying reliably in different areas of the anatomy as desired. "We also had to treat airways that are 3 mm and larger, and we have a one-size-fits-all catheter with a four-electrode array that deploys outward," recalls Dalbec. "It needs to expand in the neighborhood of 150 times, so there were challenges with fatigue and designing something that could accommodate [navigating through areas that are] 3 mm up to 10 mm or larger."
Based on feedback gleaned from early clinical studies, Boston Scientific reached out to product design consultancy Bridge Design Inc. (San Francisco) for help in optimizing the design in preparation for commercialization. Among the primary goals for the Alair system, according to Dalbec, was to reduce overall procedure time, streamline the process, and improve the user experience in a low-cost design. The two companies concurred that many of these objectives could be met by reevaluating the design of the system's handle.
The initial Alair system design, for example, demanded that a bronchoscopist operate the bronchoscope while a second person controlled the catheter, according to Dalbec. "Their first-generation product required two [people] to perform in-sync, which was awkward and relied on a lot of verbal commands," adds Matt Presta, director of industrial design at Bridge Design. "We did some observations and videotaped in the room with the surgeons doing the procedures, then we did a step-and-time analysis. We came to the conclusion that if we reduced the need for communication, this would have the biggest impact on speeding up the procedure itself."
With this in mind, Bridge Design concluded that reducing the need for communication could be achieved by crafting a handle that enabled a single user to effectively operate both the catheter and the bronchoscope. However, settling on a shape for the handle that enabled one-handed use proved to be an ergonomic challenge. To overcome this challenge, Bridge Design developed a range of concepts and even sought design inspiration from a potpourri of handheld devices ranging from pliers to spray bottles.
"We created a lot of hand-sculpted models in our shop--looking at different ways of holding the device and actuating it, as well as manipulating the catheter that is going into the bronchoscope," Presta says. "The final solution was really inspired by modern road bike levers, which allow you to perform multiple functions; you can shift and brake at the same time. We took inspiration from that, allowing the user to have a passive grip on the device so that it nests securely in the crook of your hand, freeing up your fingers to perform other tasks."
This innovative handle design, Dalbec adds, actually gives operators the option of employing the device in single-user or dual-person mode, based on preference or skill level. It offers the additional advantage of increasing mechanical advantage by enabling users to employ the entire hand for activation rather than just the thumb, Presta adds.
As a result of the collaboration between Boston Scientific and Bridge Design, the Alair system ultimately enhances the user experience, expedites the procedure, and, most importantly, improves patient outcomes, Dalbec states. "What we have seen [through studies and follow-up] is that Bronchial Thermoplasty reduces the number of severe asthma attacks, emergency room visits for respiratory symptoms, hospitalizations, and 'lost days' from either work or school. It improves patients' asthma quality of life."