New ‘patch’ uses natural body motion to fix disc herniation

The tension-activated repair patch plugs holes in discs in the spine like car tire patches, and could prevent further disease progression.

A new biologic “patch” that is activated by a person’s natural motion could be the key to fixing herniated discs in people’s backs, according to researchers at the Perelman School of Medicine and the Corporal Michael J. Crescenz Department of Veterans Affairs Medical Center (CMCVAMC). Combining years of work from many different projects, the “tension-activated repair patches” (TARPs) provide controlled release of an anti-inflammatory molecule called anakinra from microcapsules over time, which helped discs in a large animal model regain the tension they need to reverse herniation and prevent further degeneration. This pre-clinical research is detailed in a paper published in Science Translational Medicine.

A model of a spine.
Image: iStock/Benito Vega

“Currently there is no curative treatment for disc herniation, and the best thing out there is just like sticking a plain rubber plug into a hole in a tire. It will stay for a while but it won’t make a great seal,” says co-senior author Robert Mauck, a professor in orthopaedic surgery and director of the McKay Laboratory for Orthopaedic Surgery Research at Penn and research career scientist and co-director of the Translational Musculoskeletal Research Center at the CMCVAMC. “The patch we’ve developed is like the plug plus glue, so you’re actually bonding the patch. And since biomechanical movement activates the patch and makes it seal more strongly, it’s like having your tire patch get stronger the more miles you put on it.”

Herniation in the spine occurs when one of the soft discs that sits between the vertebrae develops a split or a hole, and the soft interior squeezes through. This means that the discs lose their tension and are unable to cushion the spine as usual, causing pain. To continue the tire analogy, it’s as if a tire has gone flat and the car is riding on its rim.

The Penn Medicine and CMCVAMC researchers have developed TARPs to not just plug the hole, but allow tension to build back up, and re-cushion the vertebrae. That goal has been particularly tough to achieve to this point.

Key to the TARP is having the body’s natural mechanics work to activate the release of anti-inflammatory molecules from the microcapsules within the patch. While they would theoretically still work if a person lay totally still for months, the reality of the disc tissue environment is that movement is its natural state. And because the patch makes it as if there was never a hole to begin with, its application could have significant effects on the prevention of worsening pain related to disc degeneration.

“This is designed to be an early intervention that may change the course of disease progression,” says co-senior author Harvey Smith, an associate professor of orthopaedic surgery and attending physician at the CMCVAMC. “Currently there’s no treatment to mitigate recurring herniations that actually heal the disc. So we’re looking at a disease that is very common in younger, working-age people that, downstream, leads to severe disc disease and the need for spinal fusion. The more we can prevent that, the better.”

Read more at Penn Medicine News.