Industry Watch

Bob Assell, Fortus Medical

Exploring Spinal Solutions

Med tech veteran Bob Assell has carved out a niche for fighting lower back pains.

By Angelo Gentile
Monday, August 17, 2015

Serial entrepreneur and engineer Bob Assell is optimistic about future growth in the spinal device industry, even if it seems to be in the doldrums. “I think there were too many of them, with too much redundancy in their products,” says Assell, who has launched two spinal device startups, and worked in two others. “Engineers in spine are working on the 100th version of a pedicle screw or an interbody or anterior plate or something like that, looking for a little tweak.” 

That’s why Assell’s strategy has been to explore unknown territory in the complex world of chronic lower back pain. The spine is very complicated and pain can arise in dozens of ways. However, the clinical success rate of spinal surgeries is only about 60%, says Assell. People go through an expensive surgery, and they still have the pain. That leaves a lot of room for improvement in terms of diagnosis and treatment — and for the development of novel devices, rather than merely improving old ones. The surgeons need more tools.

There is also a certain urgency in treating back pain, because it is not just a problem of those who are old and retired. The average spine patients are in their 30s and 40s, Assell says, in the middle of their prime productive years. Suddenly they lose their ability to move freely, and may no longer be able to earn a living. Aside from funneling the nerves from the brain to the body, the spine is also a load-bearing structure which is subject to a lot of stress, especially among the obese. It is also a degenerating structure, which affects everyone. Low-back pain or spine problems are the second most common cause of disability among adults in the United States behind arthritis or rheumatism, according to the Centers for Disease Control.

The challenge

Trained as an engineer, Assell started out at 3M in its surgical and orthopedic products division, where he worked on surgical powered instruments for total joints. His colleagues talked about the great potential in addressing the spine, and he eventually had the opportunity to work with one of the great innovators in the field, Dr. Charles Ray at Raymedica. Assell went on to another spinal device company, TranS1, a Twin Cities-based spinal device company that was later bought out and ultimately dissolved. His work for TranS1, however, led him to a transformative experience in Brazil.

Eight years ago he was at a clinic in Sao Paulo to see spine surgeon Dr. Luiz Pimenta. There Assell encountered a patient, an elderly woman whose face was contorted in pain. She looked at him imploringly, and he felt compelled to help her. The woman was suffering from sacroiliac (SI) joint pain, an area that often eludes treatment. “The image of that woman’s face imprinted on my mind,” says Assell, and he vowed to work on SI pain.

When he finally met with Pimenta, a noted neurosurgeon in the field, the two discussed yet another unexplored area in spine pain — facet joint pain. The facet joints connect with vertebrae to provide flexibility and enable bending and twisting. The two concluded that facet pain was an even greater unsolved clinical issue than SI pain. “Our collective opinion was that the biggest unmet clinical need was facet pain,” says Assell.

“Dr. Pimenta looked at me and said, ‘We need to find a way to fix facet joints’ … that was his challenge to me,” Assell says.

Once he found venture capital from an investor contact, Assell was ready to go. He left TranS1 that year and formed Minnetonka-based Zyga Technology. “I had the challenge (or challenges) from Dr. Pimenta, I had the money, and that’s all I needed.”


An estimated 30% of back pain comes from the facet joints. Another 20% comes from SI. Yet for fully half the root causes of back pain, spine surgeons have really had nothing in their “tool box” to permanently fix these conditions, other than palliative treatments for pain, Assell says.

He responded by inventing two minimally invasive, surgical spinal devices. The Glyder Facet Restoration Device is a non-fusion investigational product that restores damaged joints that cause chronic facet joint pain. The company’s other product — inspired by the Brazilian woman — is the SImmetry System, which addresses SI pain using a fusion approach.

As CEO of Zyga, Assell achieved FDA clearance for SImmetry, making it available in the United States. But then a funny thing happened. Assell found himself without a job.

“It was time to commercialize, so the venture guys on the board wanted a CEO who had commercialization experience,” says Assell, “So one day I was just told to pack up my office, so I left.”

He remains on the board, and takes his loss philosophically. “Nobody can do it really well from the absolute concept to commercialization,” Assell says. “Everybody has a skill set, and it is best to work in that.”

From his perch on the board, Assell has seen progress at Zyga. The Glyder Facet Restoration Device has received approval to be sold and used commercially in Europe, says Joseph Saladino, vice president of marketing for Zyga.

Zyga recently received $10 million in financing to fund studies, including a clinical feasibility study of the device in five U.S. cities. This study will be used to receive Food and Drug Administration (FDA) approval for a pivotal study and ultimate FDA approval for commercialization in the U.S. “Within the next few years, we plan to complete the clinical studies of Glyder, expand the commercialization of the product in Europe and move to acquiring U.S. approval,” Saladino says.

Dr. Darren Bergey of the Bergey Spine Institute in Colton, Calif., is a proponent of SImmetry. “I’ve used different systems in the past, but I believe the SImmetry system offers patients the best chance at a positive long-term outcome.”

Fortus and the “AutoStem”

Meanwhile, Assell has been busy doing what all serial entrepreneurs do — he launched another startup. Two years ago he founded Fortus Medical in Minneapolis, and thus far has raised close to $3 million in financing. The tentative name for the new product is “AutoStem,” a kit that produces high-grade bone graft material for bone surgeries — especially spinal surgeries.

While this product addresses the cause of back pain, among other uses, it is quite straightforwardly a pain-prevention agent for the hip. That’s because when surgeons need bone grafting material — i.e. living bone cells — the ones that work best are those from the person getting the surgery. Such “autograft” material is usually chiseled from the patient’s pelvis, and this causes damage.

“They strip all the muscle and they take big gouges and they cut big strips of bone off your pelvis, off your ilium,” says Assell. “It all scars down, so the donor site becomes a big problem after surgery.”

His solution is to extract bone marrow from the patient, sort out the red blood cells, and gather a concentrated batch of bone stem cells that form the consistency of putty. Nobody touches the pelvis; there is no chiseling. The entire process is conducted within a 30-minute period during surgery. The FDA hurdle for approval is lower, because he is using two licensed procedures, one of which has already been approved for blood — but not yet for marrow.

Does Assell fear he’s going to lose his position again when the commercialization phase approaches?

“I hope not,” he says. “We are using less venture money and more private capital. Our investors are individuals who believe in this. A lot of people aren’t comfortable with the stock market these days, so sometimes they see this as both a way to make an investment and to maybe help.”

Changing lives

The satisfaction that Assell gets from his work is multifaceted. Aside from financial considerations, he finds joy in solving problems in unexplored areas. That’s what adventurous engineers do. But then there is the profound human feedback. Assell says the most common remark from patients who have had a successful back surgery is, “I got my life back.”

“It is very satisfying to see a patient before surgery and a few weeks later I follow up and they walk in and they are smiling and they are happy,” he says. “They are telling you about the stuff they are doing now. They are going shopping or taking care of their families again. It really does change their life.”