Rochester, Olmsted County

Feature Image: Dr. Darryl Barnes uses ultrasound technology to guide the SX-One MicroKnife

Inventors at heart

There’s something about a garage that makes it well-suited for inventing things. Many of the biggest companies in the world got their start in a garage – Amazon, Apple and Google to name a few. Sonex Health in Rochester got its start the same way.

Doctors Darryl Barnes and Jay Smith have both worked at Mayo Clinic since the 1990s; Barnes, a Sports Medicine physician, and Smith, a world-renowned expert in Musculoskeletal Ultrasound technology which produces images of muscles, tendons, ligaments and joints. At the time, ultrasound technology was widely used for things like pregnancy imaging, but it had not really been applied to orthopedics, the branch of medicine dealing with correction of deformities of bones or muscles.

In orthopedics, the common practice is to perform surgery just to find the problem. This is highly invasive and can result in more issues for the patient. Both Barnes and Smith wondered if there was a way to use ultrasound technology to find the exact location of the problem and to act as a guide for instruments to make surgery less invasive.

Sonex Health

Ultrasound imaging is used to find the problem before an incision is made, and is then used to guide the tool.

As next-door neighbors, they began experimenting in Barnes’s garage by using an ultrasound machine on a turkey breast as a test subject. They tested different tools in the garage, like tubes, augers and drills, that could eventually be translated into tools for surgical devices. “I’ve always been an inventor,” said Barnes, who often invented medical technology at Mayo Clinic. “I’ve always loved tinkering around with mechanical things as they react with biological things.”

They finally started using something called “phacoemulsification technology,” a tool which was primarily being used to remove cataracts. The instrument vibrates very fast, and disrupts diseased tissue, but keeps healthy tissue intact. This led to their invention of the TX device, now licensed to Tenex Health, which is used to perform minimally invasive surgery on tendon and bone problems, like tennis elbow, jumper’s knee and bone spurs. This breakthrough placed them firmly on the frontier of a new way to treat patients.

Putting the patient first

Buoyed by their success with the TX device, they were inspired to explore other minimally invasive surgical tools that could be guided by ultrasound technology. Barnes and Smith co-founded Sonex Health in 2014 along with Aaron Keenan who has a background in nuclear engineering and healthcare and is now the Vice President of Operations for the company. Through this new company, they started focusing on developing a surgical device for carpal tunnel syndrome.

Sonex Health

Co-founder Aaron Keenan in his Sonex Health office.

There are currently about 650,000 carpal tunnel surgeries performed each year, the majority of which involve cutting open the wrist. This procedure takes four to six weeks to recover from, and multiple doctor visits. There are an additional 5.4 million patients who need carpal tunnel surgery but who don’t get it because they either can’t take the time off of work for recovery, or they are intimidated by the surgery. “We heard stories about people who owned their own salons, for example, who couldn’t be away from their business for four to six weeks,” said Barnes. And unfortunately, the longer a person waits to get the surgery, the worse the problem becomes.

Sonex Health’s solution was a very small knife that could be guided by an ultrasound. In 2015, they applied for an equity investment from Southern Minnesota Initiative Foundation (SMIF) to help develop the product. The Equity Fund provides financial capital and expertise to early stage and start-up companies. SMIF invested $75,000 in Sonex Health, which was used to help create a market-ready product by going through the engineering, verification, regulatory process, product development stages and FDA registration. “The confidence it builds when SMIF puts some capital in is very helpful,” said Barnes. “A lot of other individuals and investors that look at that and say if SMIF wants to do this then we can have confidence in that and invest in this too.”

Sonex Health

The SX-One MicroKnife device was developed for minimally invasive carpal tunnel surgery.

The SX-One MicroKnife, as the device is now called, allows patients to be wide awake during the procedure, which takes about ten minutes total. Numbing medicine is applied at the wrist, and then a tiny incision is made, about 4 to 5 millimeters in length. An ultrasound is used to identify the best pathway through the wrist to move the device into place. Once in place, the SX-One cuts the ligament which releases pressure on the nerve. No stitches are needed, and recovery time is only three to six days. Oftentimes the patient does not even need to visit the doctor for a follow-up visit. “Our solution is to bring a patient into a non-intimidating environment, complete the procedure and get them out the door within an hour,” said Barnes.

Bringing new technology to the masses

Southern Minnesota is a well-known hub for inventions in medical technology, primarily due to the presence of Mayo Clinic in the region. The Clinic draws people like Barnes, Smith and Keenan, none of whom are originally from Minnesota. “There is a lot of talent here – people want to surround themselves with cutting edge medicine,” said Barnes.

As the company grew, both Barnes and Smith found it increasingly difficult to balance running a company and practicing medicine. In 2018 Barnes took advantage of Mayo Clinic’s entrepreneurial leave policy for one year, to help commercialize the SX-One. The company has grown so rapidly that he has now completely transitioned to running Sonex Health, as the Chief Executive Officer. Smith will be joining him full time as the Chief Medical Officer for Sonex Health in the next year.

Sonex Health

Sonex Health Brochure: “Recovery in days, not months”

By 2018 about 3,000 cases had been completed with the SX-One MicroKnife with positive outcomes. “We were able to see our vision through and do it very effectively,” said Barnes. Now their goal is to bring the instrument to the masses by training doctors on how to use it. “We’ve trained about 30 doctors around the country in about 16 states,” said Barnes. “Now with the commercialization we’re adding new doctors on each day.” Sonex Health founded an institute that is part of the company and chartered with educating physicians on ultrasound guided procedures.

To support this expansion, they applied for a second equity investment from SMIF. The Rochester Area Economic Development, Inc. (RAEDI), Southeast Minnesota Capital Fund and individual angel investors partnered with SMIF on both investment rounds. “SMIF invested $50,000 which really helped us with the development of the training aspects,” said Barnes. “How we train doctors, what is the best way, and helping to fund the institute.” Most recently, they teamed up with a world-renowned research and education foundation in Florida, allowing them to educate physicians on a commercial scale.

Sonex Health now has 21 employees and is adding more by the week. As they continue to grow, they make sure to keep a finger on the pulse of the patient. “The biggest thing is the patient’s outcome and their experience,” said Barnes. “Are they better for our efforts?”

Sonex Health

Dr. Darryl Barnes and Aaron Keenan in downtown Rochester.

This story is from SMIF’s 2019 Impact Report. To read the other stories from the report, and to view maps showing the impact of these programs, visit