A Mayo Clinic spinoff company seeking to commercialize a medical device for carpal tunnel syndrome announced it has reached an impressive milestone: The successful completion of the first ultrasound-guided procedure for the hand condition in the United States.
Sonex Health, co-founded by a pair of Mayo doctors in 2014 and housed within the Mayo Clinic Business Accelerator, raised at least $2 million from angel investors for the development of the SX-One MicroKnife, described as “an ultra-low profile surgical device that allows physicians to perform carpal tunnel release surgery through a single micro-incision using ultrasound guidance.”
The company announced late in February a “first-in-man” orthopedic procedure using the device had been carried out by Dr. Craig Johnson of the Aurora Health Care Clinic in Sheboygan, Wisconsin, who also serves on Sonex’s medical advisory board.
“Our first-in-man surgery represents Sonex Health’s commitment to providing physicians with a minimally invasive solution for performing carpel tunnel release,” CEO Dr. Darryl Barnes said in a release. “We look forward to helping physicians offer their carpal tunnel syndrome patients an option that helps people get out of pain and back to work and normal activities quickly.”
Barnes, an orthopedist and sports medicine practitioner at Mayo’s Austin, Minnesota, clinic, and Dr. Jay Smith, a Mayo professor of physical medicine and rehabilitation, invented the device as a more efficient, minimally invasive and less costly alternative to traditional CPR surgery, touting better outcomes, speedier recoveries and significantly less pain.
In landing a $100,000 loan-to-equity investment from the city of Rochester in 2015, its backers said the device allows clinicians to perform carpal tunnel release surgery under ultrasound guidance in a medical office environment in “a safe, cost effective and definitive manner.”
Currently, some 500,000 CTR procedures per year are carried out by orthopedic hand surgeons in operation room settings, but with Sonex Health’s device, the company aims to multiply the number of medical professionals capable of performing the surgery by four times. At the same time, the number of carpel tunnel conditions that can be treatable with device can be raised to 12 million per year.
At that time, Rochester Area Economic Development Inc. reported Sonex founders were seeking $1.6 million in backing to develop the device and take it though clinical and regulatory pathways en route to FDA 510K approval, with $1.5 million of the total already in hand. The funds were also to be used to allow for an initial product launch of 200 SX-One MicroKnife units to be utilized in live patients.
Sonex also received a $100,000 seed investment from the Southern Minnesota Initiative Foundation as well as an additional $475,000 from accredited Minnesota angel investment funds in 2016, according to Minnesota Dept. of Employment and Economic Development documents.
The company said the microknife requires a wrist incision that’s so small it can be closed with a small adhesive bandage or strip – some five times smaller than is needed for traditional carpel tunnel surgery.
It features “Meerkat” technology that enables the device to store both its safety and cutting elements inside, thus allowing entry and exit through a micro-incision.
Once inside the wrist, its safety components are deployed in order to protect nerves, blood vessels and tendons during the procedure. The result, Sonex claims, is a combination of a low-trauma surgical environment, faster pain relief and recovery in patients.

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