(ĐTĐ) - The sural nerve runs down through the center of the calf muscle and is one of five nerves that provide sensation to the foot. It travels down the back of the leg, over the Achilles tendon, and then along the outside of the foot to the end of the little toe. Comparatively, it is a fairly minor nerve, since it only provides sensation on the outside of the foot and areas between the 4th and 5th toes.
Sural Nerve Pain Causes
While the nerve may be minor in scope, it is capable of creating a fair amount of pain and discomfort when it is irritated. Though anyone can develop this condition, it is often related to surgery in the area. When it isn’t caused by surgery, it will often be athletes who will develop it, since they regularly put stress on the area. Luckily, they are also on the look-out for foot related nerve conditions, and see doctors familiar with athletic issues on a regular basis.
Because the nerve is just under the skin, it is particularly susceptible to compression from tight shoes that put stress on the Achilles tendon. The sural nerve can be compressed between the tendon and the shoe, and the pressure can then cause something called neuritis.
Sural neuritis can also be caused by something called “entrapment.” What this refers to is when the nerve becomes tangled in scar tissue which then puts pressure on the nerve and creates pulling. This is, in fact, more serious than pressure created by a shoe. For one thing, this is a great deal more difficult to relieve. For another, the scar tissue involved is often the result of surgery in the area, so the sural neuritis can actually be conceived of as a negative side effect of surgery.
There are several likely surgical culprits that might cause sural neuritis. The most common are Achilles tendon lengthening surgery, Achilles tendon surgical repair after a torn tendon, ankle fracture surgery for a broken ankle, flatfoot surgery and fifth metatarsal fracture surgery. This list isn’t exhaustive, but it’s reasonably well known that neuritis is a risk when these surgeries are conducted.
Sural Nerve Pain Symptoms
The symptoms of sural nerve entrapment are fairly straight-forward. Generally, the symptoms are pain, and/or a numb or tingling feeling on the outside of the foot. This will only rarely have an effect on your gait, but it can definitely cause a great deal of discomfort.
Unfortunately, this can develop over time, and so people may not feel motivated to get this treated right away. In addition, this may present in combination with other pain from foot exertions, so people may just see this as a standard part of the achiness that comes with being on your feet too much.
Sural Nerve Pain Diagnosis
Because this is such a specific kind of irritation in such a small area, the diagnosis of this condition is not necessarily that difficult. That said, there still isn’t a positive test for neuritis, and your doctor will need to engage in a process of elimination. What that means is that they will investigate your symptoms and then use tests to rule out other causes. Also, because of the nerve’s location, problems with the sural nerve may easily be confused with Achilles tendon issues instead.
Especially confusing is that sural neuritis can often present as Achilles tendinitis. However, this is more to do with pronation or supination of the ankle, rather than nerve issues. So, at least, there are physical symptoms that one might be able to observe.
One of the tests that is done, is called the Tinel’s test. What this involves is percussion at the site of the nerve, in this case, the ankle. If the percussion results in tingling, pins and needles or electric shock sensations in the area, then the test is positive. A positive test is a sign of neuritis.
More technical measures might include radiography. This will rule out problems with the bones in the area. It may pick up evidence of arthritis or stress fractures that are causing you pain, and are more serious conditions.
It might be required for you to get a magnetic resonance imaging test as well. These will be used to eliminate the soft tissues in the area as the source of your issues.
Finally, your doctor may also decide to use diagnostic nerve blocks on the area. The nerve block will do just that, blocking sensations of pain and discomfort from being transmitted to the brain. The nerve is anaesthetized and then the remaining pain is assessed. If your pain is ultimately relieved by putting the sural nerve to sleep, there is a very good chance that the sural nerve is the source of your problems.
Sural Nerve Pain Treatment
Treatment can involve self-care measures, medication and also more radical measures, like surgery might be required. Like a regular type of injury, the sural nerve will respond to cold temperatures. The first thing to do is to apply ice to the area to ease irritation and inflammation of the nerve.
Make sure your shoes aren’t responsible for the compression. If your footwear has straps or seams that press on the Achilles tendon, then it’s time to replace them.
You can also start taking non-steroidal anti-inflammatory drugs like ibuprofen. These drugs are not only pain relievers, they also act to reduce inflammation, which will relieve both the irritation and pressure on your sural nerve.
Your doctor may also decide that steroid injections as well. These are done to relieve inflammation, so it will relieve the stress on the nerve.
Finally, if there are no other options left, then it is possible that surgery may be used to release the nerve from entrapment. As in most conditions, surgery is a last resort, undertaken when there don’t seem to be other measures that will be helpful.