What are entrapment neuropathies?
Entrapment neuropathies is the umbrella term for a host of different nerve problems. These problems exist when nerves are pinched, crowded, snagged, or restricted. Other terms for entrapment neuropathies include compression neuropathies, nerve compression or pinched nerves.
How do entrapment neuropathies happen?
There are several different scenarios that may cause an entrapment neuropathy. For example, carpal tunnel syndrome is an entrapment neuropathy. There is a space in the wrists formed by the bones in the wrist and a ligament that goes over the bones, called the carpal tunnel. It’s a tunnel through which the median nerve travels as it goes from the forearm to the hand. Tendons, blood vessels and other structures are also in the tunnel and can crowd and irritate the nerve. The irritation can cause chemical changes that make the nerve hurt, tingle , or otherwise cause discomfort.
The median nerve also happens to transverse the elbow. Normally it travels between two slips of muscle called the pronator teres. If the muscles get enlarged from working out, they may crowd the nerve and cause it to get irritated.
A third way that compression happens is an influence from outside the body. For example, when you’re riding a bike, your wrist is bent and you’re putting pressure in your hand and wrist. In that position, the ulnar nerve can get irritated as it goes through the wrist.
Nerves can also get crowded, pinched or restricted from other conditions happening. If you have a cyst, for example, the cyst can pinch a nearby nerve.
Peripheral Nerve Anatomy
Nerves aren’t as simple as metal wire. They’re more like a kind of high-tech data wire that has multiple other wires in them to transmit complex information to and from different parts of our body. Since nerve are complex, there are many different parts that can get irritated and cause symptoms from physical or chemical irritations.
As we move our body, we think of our muscles and tendons moving, but nerves move too. Nerves are designed to glide between tissues in our body, and a nerve that can’t slide freely is irritated. Even if there is nothing pinching or crowding the nerve, a nerve can become irritated if it has trouble gliding because it is inflamed.
Symptoms of Entrapment Neuropathies
Classic symptoms of nerve pain include burning cold, burning hot, numbness or tingling, and shooting-type or electrical-type pain, but not everyone has the classic symptoms. Some people may have an achy pain, that needs to be distinguished from other types of pain.
Nerve pain often radiates or travels along the length of the nerve and may cause symptoms in areas away from where the pinching or crowding is actually occurring. For example, a nerve entrapment of the common peroneal nerve in the knee may cause symptoms at the ankle because the nerve transmits information to and from that area.
Nerves or blood vessels can cause exertional fatigue, when muscles that you use get tired out more easily than before. Severe nerve problems can also cause muscle dysfunction, muscle weakness and shrinkage of muscle bulk.
Diagnosing an Entrapment Neuropathy
- Talk with the patient to get the history and symptoms
- Detailed physical exam
- Pressing on the nerve, tapping on the nerve, or putting the body in positions where the nerve is trapped can give information about what is happening to the nerve.
- Diagnostic testing
- X-rays, CTs, and bone scans help rule out other potential causes.
- MRIs and ultrasounds give direct information about how a nerve is doing.
If a patient has a symptomatic side and a non-symptomatic side, the two sides can be compared to see differences.
- Electrodiagnostic studies test the electrical activity of the nerve.
Treating Entrapment Neuropathies
The details of treating a person will depend on the type of nerve, the type of entrapment and the activities that the patient wants to be able to do.
Initial Treatments
Rest the Nerve
We want to limit the amount of irritation the nerve receives. If a person is doing a daily activity that is chronically pinching a nerve, wearing a splint may help the nerve calm down.
Relieve the Nerve
Medications that reduce inflammation or how much the nerve fires may help reduce symptoms and pain, as can injections such as cortical steroids and nerve blocks.
Rehabilitate the Nerve
Formal physical therapy, home exercise, and nerve glide exercises that try to re-establish the sliding of the nerve all may be helpful.
Release the Nerve
Both non-surgical and surgical treatments to release the nerve are available.
Peripheral Nerve Stimulation
An implantable electrode that can stimulate the nerve to provide relief from symptoms may be helpful.
Surgical Treatment
There are a variety of surgical treatments to release a nerve, depending on the specific circumstances. Some involve surgery to release scarring around a nerve to allow it to glide more freely. Sometimes the nerve is moved to a different place. You’ll talk with your surgeon about the specific surgery that is right for your case.
Hydrodissection
Hydrodissection is a non-surgical treatment of an entrapped nerve, designed to reestablish the healthy gliding of the nerve. Using an ultrasound, a needle is inserted that adds fluid around the nerve to open up the space around the nerve, peeling off scarring from the nerve and allowing the nerve to float in the fluid. The fluid is absorbed by the body over a few days, but the nerve has had an opportunity to be released and to become less irritated.
The positive effects of hydrodissection may vary from lasting a few days to permanently fixing the issue and everywhere in between. The type of nerve, which nerve, how badly the nerve is entrapped, and the patient’s metabolic conditions are all factors that influence how long a hydrodissection works.
Hydrodissection may be done in an office, in a surgery center, or in the hospital.
Frequently Asked Questions
Is neuropathy from peripheral nerve entrapments the same type of neuropathy as after chemotherapy or similar treatments?
No, it’s not. Nerve entrapments involve something happening physically to the nerve: pinching, crowding, snagging, etc. With neuropathy from chemotherapy or similar systemic neuropathies, the medical and biological health of the nerves themselves are affected.
However, many people with diseased nerves from a systemic cause like chemotherapy are more likely to develop entrapment neuropathies. If there is one place where the neuropathy has gotten worse, they may have a nerve entrapment that may be able to be treated.
What is the difference between spine and non-spine neuropathies?
Location is the difference. If you think of nerves like a tree, the spinal cord is the trunk. The nerves are the branches that come off the trunk, and then even smaller branches come off of those. Nerve entrapments in the spine are entrapments around the trunk and where the branches first leave the trunk. Anything outside of those are peripheral nerves.
A tree with a diseased small branch may have some leaves affected, and a tree with a diseased larger branch will have smaller branches affected. If you have a disease that affects the trunk of the tree, it affects more of the tree. Nerve problems in the spine affect a larger part of the body.
Some treatments are the same idea but use different techniques depending on the location of the nerve that they are treating, since different parts of the body have different anatomy.