Regenerative Medicine for Neuropathy: Where the Injection Goes and What It Quiets

Regenerative medicine for neuropathy, as we practice it in St. Louis, means placing your own platelet-rich plasma (PRP) exactly where an irritated pain fiber lives: along its path, at the spot where it is trapped, or beside the root where it leaves the spine. The goal is to calm the inflammation around it and quiet the fibers that keep firing on their own.

Most neuropathy care is a pill that works on the whole body to turn down one signal. An orthobiologic works the other way around. It is a small dose, placed under ultrasound or live X-ray, in one spot. So the real question is not which product. It is which spot.

That depends on where your pain is being made. There are three common answers, and each one gets a different needle.

What is injected in regenerative medicine for neuropathy?

PRP does most of the work. We draw your blood, spin it down and concentrate the platelets during the same visit. Platelets carry signaling proteins that tell the tissue around a nerve to settle down.

Bone marrow aspirate concentrate (BMAC) comes from your own hip bone. Which of the two you get is decided at the exam, not from a menu.

How we make each product is on how orthobiologics are prepared, and the full menu is on orthobiologics.

Why put an injection next to a nerve at all?

Because in painful neuropathy, the fibers near the injury are often doing the talking. C-fibers are the thin, slow fibers that carry burning pain. Scientists can record single fibers in a living person’s nerve. In people with painful polyneuropathy, 40.5% of these fibers were firing or oversensitive on their own. In people with the same nerve disease and no pain, it was 14.6% (Kleggetveit et al., 2012).

Diabetes pushes the same switch harder. In patients with type 2 diabetes and painful neuropathy, 72% of recorded pain fibers were firing on their own, against 15% in diabetic patients without pain. In diabetic mice, the trigger was methylglyoxal, a toxic by-product of high blood sugar, acting on a channel those fibers carry (Becker et al., 2023).

Here is the part most people never hear. In 14 patients with painful peripheral neuropathy, numbing the nerve below the knee wiped out the pain in every one of them, within about 10 minutes. The drug level in the blood was too low to work on the brain (Haroutounian et al., 2014). The pain was being kept alive from the outside in. That is why the target is the tissue around the fiber, not the whole body.

What happens when PRP is placed along the nerve?

This is the target for neuropathy that runs along a nerve, like the burning feet of diabetic neuropathy. Under ultrasound, the PRP is laid in the thin layer of tissue that wraps the nerve, the perineural space, at the points where the nerve is most irritated.

The best trial of this approach was done in Egypt. Sixty adults with type 2 diabetes had painful neuropathy for at least six months. Half got ultrasound-guided PRP around the nerves plus their usual medicine. Half got their usual medicine alone. The PRP group had less pain and less numbness at 1, 3 and 6 months, and their nerve exam scores improved more (Hassanien et al., 2020).

What we are after is a calmer neighborhood. Less swelling and inflammatory chemistry in the sheath means less fuel for a fiber that has learned to fire without a reason. If the burning feels like a nerve soaking in something toxic, the chemistry of that is laid out in burning nerve pain.

What if the nerve is trapped in one spot?

Then the needle goes to the spot. Some nerve pain comes from one place where a nerve runs through a tight tunnel, a band of tissue or a scar. Carpal tunnel at the wrist is the famous one. Others are filed under the wrong name for years.

The superior cluneal nerve is a small nerve that crosses the top of the pelvic bone. In 834 people with low back or leg pain, 14% met the criteria for trouble at this one nerve. About half of them had leg symptoms that looked like a spine problem. After up to three nerve blocks, 68% had more than half their pain relieved (Kuniya et al., 2014). A nerve cut during a knee replacement can do the same thing, two inches below the joint line, and get treated as a failed knee.

At a trapped point we often combine two things. Hydrodissection uses fluid under ultrasound to lift the nerve off the tissue pinning it. PRP then goes into the tunnel around it. In a randomized trial of 60 people with mild to moderate carpal tunnel syndrome, one ultrasound-guided PRP injection beat a night splint at six months. Pain was lower, hand function was better and the swollen median nerve was measurably smaller (Wu et al., 2017). The wrist version of this work is on PRP for hand pain and carpal tunnel.

Can an injection reach the nerve root and the ganglion?

Yes. This is the third target, and the one most people do not know exists. Every nerve in your leg or arm has its cell bodies parked in a small cluster just outside the spine. That cluster is the dorsal root ganglion, or DRG. When nerve pain is chronic, the DRG can become a generator of its own.

The strongest proof comes from phantom limb pain, pain in a limb that is no longer there. In 31 people with amputations, a dilute numbing medicine placed on the DRG shut the phantom pain off. The dose was too weak to block signals coming from farther down the nerve. The authors concluded the pain was driven mainly by activity made inside the DRG (Vaso et al., 2014).

So for pain that starts at the root, the PRP goes through the opening where the root leaves the spine, under live X-ray, so it bathes the root and the ganglion. In a randomized trial of 30 people with a single herniated lumbar disc, PRP placed this way was compared with the steroid triamcinolone. The PRP group had less leg pain at 6, 12 and 24 weeks and better function at 24 weeks. Neither group had a side effect (Wongjarupong et al., 2023).

What we are aiming for here is a reset. A ganglion that has been sensitized for months has learned to treat ordinary input as an emergency. Calming the inflammation around it gives it room to settle back out of that state. If injections at the spine have worked and then worn off for you, why nerve blocks and epidurals stop working explains the pattern.

How do you decide where the needle goes?

We test before we treat. The target comes from four things, in this order.

• A hands-on exam. A fingertip on the right spot can reproduce the pain in seconds. Loss of feeling, and pain from light touch, show where the nerve is affected.
• The pattern of your pain. In 902 patients with peripheral nerve pain, about one in three had an “irritable nociceptor” pattern: feeling mostly intact, but pain from heat and cold (Baron et al., 2017). That pattern points at overactive fibers near the injury, which is exactly where this treatment works.
• Nerve testing. An EMG and nerve conduction study, done and read by a physician, shows which nerve is involved and at what level.
• A test block. A small amount of numbing medicine at the suspected spot. If the pain goes away for the hours the medicine lasts, we have found the generator. If it does not, we keep looking before any PRP is used.

Dr. Padda has written plainly that he has watched good physicians treat a nerve as if it were a joint, and that he has done it himself. The test block is the habit that came out of that. It costs one visit, and it keeps a good treatment from landing on the wrong spot.

Many patients have more than one target. Diabetic feet with a pinched root in the low back is common. Then the plan covers both, one spot at a time, based on how each one responds. Clinical need sets the number of injections. There is no fixed series.

What keeps the nerve quiet after the injection?

The chemistry that lit the fiber up in the first place. Insulin itself turns up the volume on these nerves. In DRG nerve cells from mice, insulin made the response to capsaicin, the hot chemical in chili peppers, stronger. When the insulin receptor was blocked, the extra response went away (Hori et al., 2022). Methylglyoxal from high blood sugar sensitizes the same fibers from another direction (Becker et al., 2023).

That is why fasting insulin, glucose control and inflammation markers are part of the plan, not an afterthought. An injection that calms a fiber is working against a body that keeps sensitizing it. The tests we run are on the metabolic audit.

The food supply makes this harder than it should be. The cheapest calories in most St. Louis grocery stores are refined starch and sugar, the exact foods that raise insulin all day. That is a pricing problem, not a character flaw. We plan around it with you: protein first, real food, sleep that lets insulin fall overnight, and walking that the nerve can tolerate. The bigger picture of nerve pain, blood sugar and the neck is on neuropathic pain.

The injection buys the window. What you eat, how you sleep and how you move decide whether the window stays open.

Frequently asked questions

Is PRP near a nerve the same as a nerve block?

No. A nerve block uses numbing medicine to switch the signal off for hours. We use a block as a test to find the spot. PRP is placed at that spot afterward to calm the inflamed tissue around the nerve, so the fiber has less reason to fire.

Can I have this if I have diabetes?

Yes. Diabetic neuropathy is one of the most common reasons people come to us. In a randomized trial of 60 adults with type 2 diabetes, PRP placed around the nerve lowered pain and numbness for six months. We check your blood sugar and insulin first, because they shape how well the result holds.

Should I stop gabapentin or pregabalin before treatment?

Do not change any nerve medicine on your own. Stopping these drugs suddenly can cause withdrawal symptoms. If the injections work, your physician lowers the dose with you, step by step.

How is this different from a pill for nerve pain?

A pill reaches every nerve in your body to turn one down, which is why drowsiness and fog are common. An injection is placed in one spot, under imaging, where testing shows the pain is being made. Many patients use both for a while.

Sources

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