People who have a herniated disc often complain about the lack of non-invasive treatment options, but there are some on the horizon. These include new types of injections to dissolve the extruded disc, therapies targeting nerve pain, and therapies to heal the disc. Some are already offered on the market, while others still have a long way to go.
Currently available conservative therapies for herniated disc include physical therapy, injections, and pain medication. When these fail, the next step is often back surgery, which new therapies aim to avoid. Some people develop chronic pain related to the herniation.
Chemonucleolysis is a process by which an enzyme is used to dissolve extruded disc material. In this way, the treatment may help alleviate pressure on the spinal nerve root, along with related inflammation and pain.
The first agent to be used for chemonucleolysis was chymopapain, derived from an enzyme found in papaya. Although it was clinically successful in reducing the size of disc herniation and symptoms, it was removed from the market in 2002, for reasons that may include financial and safety concerns.1
There were a few potential complications with chymopapain. Approximately 3% of North Americans are allergic to the papaya enzyme.2 Other complications noted included discitis, subarachnoid hemorrhage, paraplegia, and possibly acute transverse myelitis. But those in favor of using chymopapain say these can be avoided by screening patients ahead of time.
As chymopapain fell out of favor, the interest in and awareness of chemonucleolysis as a spine treatment was suspended, until recently. New enzymes are now being tested for safety, as well as their effectiveness at dissolving the disc material. These enzymes are collagenase, MMP-7, ethanol gel, and condoliase.
The enzyme collagenase is good at splitting collagen molecules, especially the type that is found in the nucleus pulposus of the disc. The nucleus pulposus is the soft, jelly-like center of the disc that allows the disc to withstand compression and torsion (twisting). This ability allows the disc to absorb shock that occurs during movement.
Collagenase has less risk for allergy than chymopapain, plus a good track record for decreasing symptoms in patients with lumbar disc disease.3 But collagenase is not without its own risks for complications. It’s possible that taking this drug, which is often given by injection, may lead to hemorrhage, paraplegia and/or erosion of the endplate of neighboring vertebrae.
Condoliase was approved by the drug regulatory authority in Japan for lumbar disc herniation. The enzyme was found in the bacterium Proteus vulgaris. It targets chondroitin sulfate, which is present in the nucleus pulposus and is more specific in its targets than chymopapain or collagenase. This makes it less harmful to surrounding tissues. Clinical trials have found success and a good safety profile.4 More clinical trials are ongoing.
Matrix mettaloproteinase-7 (MMP-7) is another enzyme that breaks down proteins. It works similarly to chymopapain but perhaps offers more safety. Lab experiments on animals have been done on MMP-7.5 But as of June 2020, studies on humans have yet to be conducted.
Ethanol gel is applied by fluoroscopy to a herniated disc to help to hurry tissue death of the extruded nucleus pulposus material. Originally, the drug contained only ethanol. While this first version did yield some good results for patients, it was thin and runny, leading to leaking in nearby areas, which caused pain.
Ethylcellulose, a thickening agent, was added to try to mitigate this unwanted side effect. A radiopaque substance was also added to enable surgeons to see the disc while operating, as well as to detect any leaks from occurring during the procedure.
Authors of a 2017 review published in the Journal of Pain Research reported the results of several studies involving patients with lumbar and cervical disc herniation who underwent treatment with ethanol gel.2 They cite, for example, a study demonstrating 44% to 62% reduction in pain after ethanol gel injection.
A 2018 study of patients with symptomatic disc herniation who didn't get relief with conservative treatment found significant pain relief and reduce disability.6
There are a couple of treatments that aim to address the role nerves play in low back pain.
Regrowing nerves of the peripheral nervous system, in other words, those located outside the brain and spinal cord, is another strategy for managing symptoms related to disc herniation due to degenerative spinal changes. Examples of such symptoms include sciatica and nerve injury.
Some scientists are interested in doing exactly this for spine patients. Unfortunately, progress is slow. In the past, scientists used growth factors to help regenerate injured peripheral nerves. In the process, though, they found that these substances also caused pain, pins and needles sensations, and/or bowel urgencies.
Enter a new type of growth factor that works specifically on sensory neurons, which are those nerves that relay information to your brain about the things you feel—temperature, joint position, muscle tension, tickling, and pain.
Neublastin (also called artemin) is considered a neural regrowth drug (or nerve regeneration drug). Researchers envision that neublastin will be given to patients by systemic infusion, yet it will have only the targeted effect of modulating pain due to injured peripheral nerves. Researchers also anticipate that the side effects mentioned above will not be an issue for patients.2
Neublastin has shown promise in animal studies as well as a few done on humans, specifically for sciatica or lumbosacral radiculopathy.7 More studies need to be completed before the drug can go mainstream.
Tanezumab, manufactured by Pfizer and Eli Lilly, is another drug that seeks to relieve back pain by addressing nerves. It affects the way in which nerve activity is modulated, blocking pain signals so you don’t feel them. This, in turn, may also help you function better in your daily life.
Both long and short-term studies comparing tanezumab to naproxen (an anti-inflammatory pain medication) and opioids found that tanezumab can hold its own against these, and even provide better pain relief.8
However, Tanezumab has risks for complications. While most are mild enough that clinical trials had few people discontinuing treatment, one concern is for rapidly progressing osteoarthritis.8 If your doctor suggests tanezumab, you may want to ask the hard questions about side effects and complications before assuming it will be helpful as a part of your back pain management plan.
In March of 2020, the U.S. Food and Drug Administration accepted the regulatory submission for tanezumab for the treatment of chronic pain due to moderate-to-severe osteoarthritis.
Disc Cell Regeneration
Another way to heal your disc-related pain in the future may be by regenerating the cells of this structure. Two therapies—platelet-rich plasma and stem cell treatment—may hold promise for people with disc-related back pain. But as of yet, not enough research has been done for doctors and experts to be able to recommend these for back patients.
Platelet-rich plasma (PRP) is an injection of your own blood into an injured area. The blood is first treated by centrifugation to remove red and white blood cells and increase the concentration of platelets in the liquid plasma. Platelets (cells that are instrumental in blood clotting) may be helpful to injury healing because they contain a specific type of protein called growth factors.
PRP has been on the radar of research scientists since 2011 and since then a handful of studies have cropped up.2 But there’s not enough evidence for experts to recommend PRP for disc-related pain.
While platelet-rich plasma is considered a very safe therapy, using it for disc disease specifically has its challenges. Some of these include the age of the patient, the potential cost of the treatment, and few blood vessels in the disc, which makes it difficult for PRP to do its job of bringing cells closer together, necessary for the healing process.
The American Academy of Orthopedic Surgeons says PRP risks are about on par with those associated with cortisone injections.9 These include infection, tissue damage, and nerve injuries.
Platelet-Rich Plasma Injections
Stem Cell Treatment
Stem cells have the potential for developing into many different cell types. For internal repair, they can divide to replenish other cells. For the most part, stem cells used in disc treatment research are obtained from adult donors rather than embryos.
Scientists have been studying adult stem cells found in the bone marrow since the 1950s. One type forms blood cells while another type forms mesenchymal cells, which go on to generate bone, cartilage, and fat cells that support fibrous connective tissue. It’s these mesenchymal cells that could possibly be useful in disc-related procedures.
But stem cell treatments for disc and other spine-related disorders are not well studied. And most, if not all, studies on this subject have been done on animals rather than humans.
Critics of stem cell treatment for back pain say that keeping the cells sterile, lack of research on stem cells for disc disorders, and potential use of filler material all raise flags as to the safety and/or effectiveness of this treatment.2
Using Stem Cells to Cure Arthritis and Cartilage Damage
A Word From Verywell
While many novel therapies are still in the testing and study phase, a few, such as ethanol gel, PRP, tanezumab and certain aspects of chemonucleolysis are developing robustly. However, most have not been tested enough to justify their use in spine medicine. Recovery from disc herniation is generally successful, possibly because the disc tends to resolve itself in the span of about a year by resorbing back into the body.