The LimiFlex device is shown here. courtesy Boulder Neurosurgical and Spine Associates

Less invasive: Boulder docs test new spinal treatment

Surgeons conduct a LimiFlex surgery as an alternative to traditional spinal fusion surgery. courtesy Boulder Neurosurgical and Spine Associates

BOULDER — Boulder Community Health, in partnership with Boulder Neurosurgical and Spine Associates, is the only location in Colorado participating in a clinical trial to evaluate a new treatment for a spinal condition called degenerative spondylolisthesis. The trial is controlled by the U.S. Food and Drug Administration; surgeries for qualified patients are performed at Boulder Community Health by the surgeons of Boulder Neurosurgical and Spine Associates.

Robert Vissers – president and CEO of Boulder Community Health

The trial demonstrates Boulder Community Health’s vision of creating thoughtful partnerships that help impact personal and public health while providing optimal care for the community, said Dr. Robert Vissers, president and chief executive officer of Boulder Community Health.

“Clinical trials are a great example of how we put our vision into action,” said Vissers. “In this case, we’re partnering with the surgeons of Boulder Neurosurgical and Spine Associates to give our community access to a state-of-the-art technology that would not be otherwise available. Both Boulder Community Health and our physicians recognize that scientific research, evidence-based medicine and clinically proven outcomes are all critical to providing quality patient care.”

The purpose of the study is to evaluate the LimiFlex Paraspinous Tension Band, a device used during surgery that helps stabilize the spine without fusing it. Spinal fusion is a common treatment for degenerative spondylolisthesis. Unlike spinal fusion, the LimiFlex device preserves motion in the spine.

Degenerative spondylolisthesis most commonly occurs in people over the age of 50 and can become even more common in people over the age of 65, said Dr. Alan Villavicencio, senior managing partner at Boulder Neurosurgical and Spine Associates and principal investigator for the LimiFlex trial.

Dr. Alan Villavicencio is pictured in an operating room. courtesy Boulder Neurosurgical and Spine Associates

“As we age, our spine changes due to wear and tear from normal, everyday activities,” said Villavicencio, a neurosurgeon with training in both neurosurgery and orthopedic spine surgery. “Spine ligaments thicken and widen, spinal discs lose height, joints get bigger and your bones may grow spurs. With spinal stenosis, these changes cause spaces in the spine to narrow and press against spinal nerves. Many people with spinal stenosis also have spondylolisthesis, a type of instability where one spine bone slips forward over the one below.”

All of this can add up to pain in the low back and legs and tingling, numbness or weakness in the legs. In some cases, these symptoms can be successfully treated with physical therapy, medication or injections, allowing the patient to avoid surgery. However, in cases where non-surgical treatments fail to provide lasting relief, a surgical procedure known as decompression is often recommended, said Villavicencio.

“This procedure involves trimming or removing the bones and soft tissue pressing against the nerves, thereby relieving pain at the source,” said Villavicencio. “However, removing bone increases spinal instability. To compensate for this, surgeons often use screws and implants to fuse together segments of the spine to help stabilize them, a process known as spinal fusion. Although spinal fusion helps keep the spine stable following decompression, it also eliminates natural motion between spinal bones, which can lead to further problems.”

Enter the LimiFlex device. The device is used during a standard decompression surgery; it is designed to stabilize the spine without fusing it, thus preserving motion in the spine.

“LimiFlex does not involve any screws or bone grafts, which eliminate the natural motion between spine segments,” said Villavicencio. “Rather, it is made of two spring-like titanium rods that are wrapped around the back of two spine segments. This provides stability to the spine while also allowing the spine to move in a controlled manner. The LimiFlex device is placed following a standard decompression surgery, typically in less than 30 minutes.”

The surgery is minimally invasive and offers the patient reduced blood loss during surgery and a faster recovery time after surgery, in comparison to spinal fusion surgery. It may also help patients avoid more spinal surgeries down the road.

“Fusion remains the standard of care for patients diagnosed with spinal stenosis and spondylolisthesis who are undergoing surgeries,” said Villavicencio. “However, fusion of mobile spinal segments may cause additional stress on the adjacent levels, which can lead to accelerated degeneration and breakdown of these segments, requiring additional surgeries or revision surgeries if it fails to fuse in the first place.”

Boulder Neurosurgical and Spine Associates is currently enrolling patients in the LimiFlex clinical trial. Enrollment is expected to continue through December 2020 and patients will be followed for five years after enrollment. More information about the study, including qualification criteria, can be found online at or by emailing

An X-ray shows the positioning of the LimiFlex bands.courtesy Boulder Neurosurgical and Spine Associates