• Posted June 9, 2022

Injected 'Hydrogel' May Be New Option Against Back Pain

Like fixing a flat on the roadside, a new injectable hydrogel is showing promise as a remedy for worn-down spinal discs -- pumping them back up and relieving chronic back pain.

The gel, with the brand name Hydrafil, is injected directly into worn discs using X-rays to guide the needle, said lead researcher Dr. Douglas Beall, chief of radiology services at Clinical Radiology of Oklahoma in Edmond. As outlined in a pilot study,. the gel fills in cracks and tears in the spinal disc, adhering to the disc's center and outer layer.

"It goes in as a heated liquid that cools off and becomes kind of the consistency of a medium hard eraser," Beall said. "It creates kind of a Fix-a-Flat, filling the disc back up and returning the biomechanical integrity of the disc."

Twenty patients treated with the gel experienced a 67% reduction in their back pain during a one-year follow-up, Beall said.

The patients also experienced an 85% improvement in disability caused by their back pain. Beall said the gel caused no harmful reactions in any of the patients.

The bones in your spinal column -- the vertebrae -- are separated by rubbery cushions called spinal discs. These discs act as shock absorbers, preventing the vertebrae from rubbing together and allowing you to move, bend and twist comfortably.

Degenerative disc disease occurs as people age. Spinal discs tend to dry out and wear away over time. They also can be torn or injured as a result of daily activities or sports.

By Beall's estimates, as many two-thirds of people with back pain caused by degenerative disc disease could be considered candidates for this hydrogel therapy.

He is scheduled to present these findings Sunday in Boston at a meeting of the Society of Interventional Radiology. Findings presented at meetings are considered preliminary until published in a peer-reviewed journal.

Hydrafil was designated as a breakthrough device in 2020 by the U.S. Food and Drug Administration, which allows expedited review when evidence suggests an experimental product could provide more effective treatment for a serious condition compared to current options, researchers said.

Other hydrogels already are being used to treat injured or worn discs, but those products are inserted surgically as a soft solid, "which can pop out of place if you're not highly skilled in placing it," Beall said.

"Because this gel is injectable, it requires no incision, and it augments the whole disc, restoring its structural integrity, which nothing we have currently can do," he said.

Dr. J. David Prologo, an interventional radiologist at Emory University School of Medicine in Atlanta, reacted to the findings.

"The impact of this study I don't think can be overstated -- degenerated disc disease is a condition that affects hundreds of millions of people worldwide, for which there is really no definitive treatment other than a big surgery, with all of the associated costs and risks," he said.

"Dr. Beall is spearheading the ability to literally inject a liquid replacement to the disc using only a needle and image guidance, removing the needle after the injection and sending the patient home with a replaced disc and Band-Aid over the puncture site," said Prologo, who chairs the Society for Interventional Radiology's Pain Management/MSK Clinical Specialty Council.

Dr. Alan Hilibrand, co-director of spinal surgery at the Rothman Orthopaedic Institute in Philadelphia, agreed.

Disc repairs conducted via injection are "almost like the holy grail of treatment for back problems," he said.

Hilibrand noted that other research groups are trying to repair discs by injecting growth factors or biologic agents intended to promote regrowth of healthy disc material.

These new results come from what Beall characterized as an early feasibility trial, which was conducted among 20 patients ages 22 to 69 in Colombia. All had chronic low back pain due to degenerative disc disease.

A pilot trial involving more patients is underway in Canada, and based on those results a full-scale clinical trial will be conducted in the United States.

The hydrogel therapy is new, but relies on existing techniques and skills regularly used by interventional radiologists, surgeons and other specialists, Beall and Prologo said.

"Interventional radiologists already embody the skillset to perform this procedure," Prologo said. "Widespread dissemination should follow FDA approval and U.S. studies reproducing its effectiveness. The cost will be many multiples less than an open surgical alternative."

One major question remains, and should be answered by the full clinical trial: How long will the hydrogel last in a repaired disc?

Beall said Hydrafil has been subjected to a "repetitive stress simulation that simulates 90 years of stress and strain, so hopefully this will be a forever fix."

But that will need to be demonstrated in actual humans over time, Hilibrand said.

Trials will need to show that the gel "can be maintained in the disc and doesn't wear out or leak out over time," he said.

"If something lasts for six months or even 12 months, I don't think that we as a society can afford to pay for that," Hilibrand said. "It may not be very cost-effective if it only lasts for a short period of time."

ReGelTec Inc. is the company that developed Hydrafil, and paid for this early feasibility study, Beall said. Beall is a medical adviser to the company.

More information

The Arthritis Foundation has more about degenerative disc disease.

SOURCES: Douglas Beall, MD, chief, radiology services, Clinical Radiology of Oklahoma, Edmond, Okla.; J. David Prologo, MD, interventional radiologist, Emory University School of Medicine, Atlanta; Alan Hilibrand, MD, co-director, spinal surgery, Rothman Orthopaedic Institute, Philadelphia; Society of Interventional Radiology, news briefing, June 8, 2022; Society of Interventional Radiology Annual Scientific Meeting, Boston, June 11-16, 2022