Negative pressure wound therapy (NPWT) is a widely used modality to improve healing of acute and chronic wounds though the application of topical reduced pressure. This therapy helps to literally suck wounds closed. Non-healing wounds from diabetes or bed sores are pervasive healthcare problems, and although patients can benefit greatly from devices that deliver NPWT as demonstrated in hundreds of studies including randomized controlled trials, the costs associated with devices that provide this therapy continue to rise. In 2009, the costs associated with NPWT rose to the eighth most expensive in Medicare’s entire durable medical equipment category. With government emphasis on reducing healthcare spending, there is a need for an alternative to traditional NPWT devices.

Fig. 1 – The SNaP system, born out of the Stanford University Biodesign Innovation Program, utilizes specialized mechanical springs to generate negative pressure at the wound bed. At 2.2 ounces, it is lightweight and costs less to produce than heavier traditional pumps used in similar systems.

One such device is the SNaP Wound Care System (Smart Negative Pressure), originally developed out of the Stanford University Biodesign Innovation Program. In 2007, Kenton D. Fong, M.D., Moshe Pinto, and Dean Hu started a class project and redesigned negative pressure wound therapy from the ground up. As a result, the team developed a device using a constant force spring mechanism, which replaced the large electrically powered pumps commonly used in these systems. The result is the SNaP System, a device the size of a cell phone. It weighs just 2.2 ounces and costs significantly less to produce than heavier traditional pumps.

Dr. Fong, a plastic surgeon, had seen a lot of chronic wounds that would stagnate and not heal for months or even years. He also witnessed the amazing effects of negative pressure wound therapy on wound healing, with some wounds healing in half the time it took with conventional dressings. Although there was good scientific and clinical evidence that chronic wounds benefit from NPWT, the team observed that many patients were not getting treated with NPWT. To better appreciate why, they talked to dozens of clinicians and chronic wound care patients to understand their concerns with current NPWT devices.

It turned out that the bulky, loud electrical pump and dressings of existing NPWT devices were not used because they weren’t optimized for treating the typical smaller chronic wounds, including diabetic foot ulcers, venous ulcers, and pressure sores seen in the clinic setting. Moreover, patients didn’t like wearing the devices because they interfered with their lifestyle and were often embarrassing when noticed in social situations. And, these devices were difficult to obtain because they required monthly rentals, which were very expensive.

With these considerations in mind, the team started with a blank sheet of paper and came up with the SNaP Wound Care System, which led to the founding of Spiracur Inc. (Sunnyvale, CA) in August 2007.

How it Works

Although this new NPWT technology delivers the exact same negative pressure to wounds, it is different from any other system that is available. Unlike traditional NPWT devices that utilize electrically powered pumps, the SNaP System uses specialized mechanical springs to generate negative pressure at the wound bed. Because of its inventive design, the SNaP device is the first and only ultra-portable NPWT device.

Most importantly, in a multicenter randomized-controlled trial, the SNaP device demonstrates similar healing to the market- leading electrically powered pump device for refractory chronic wounds. To date, this 17-center study is the only head to head randomized controlled trial done comparing NPWT devices. This work also demonstrates that the SNaP device is easier to use and has much less impact on the quality of life of patients, interfering less with overall activity level, sleep, and social interactions due to its miniature size and ease of use. In addition, it requires half the time of skilled nursing staff to apply to wounds.

Where it Stands

The FDA cleared the SNaP System in August 2009 in a new therapy category defined as “non-powered” NPWT devices, and Spiracur obtained CE Mark for the device in December 2010.

Because the technology does not require an electrical power source to work, the device is a viable alternative for use in developing nations where electrical power is unreliable. Spiracur is committed to making a difference in healing wounds worldwide, not just in developed Western countries. The device has been used successfully in Haiti and Tanzania, and as part of the licensing agreement with Stanford University, Spiracur makes the SNaP device available at cost to developing countries.

More Information

For more information about the SNaP System, visit

Medical Design Briefs Magazine

This article first appeared in the January, 2012 issue of Medical Design Briefs Magazine.

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