The most common causes of nerve injury are injury at the point of impact, compression of the nerve by nearby structures, and trauma during surgery. Of these two, the most common nerve lesion is from the impingement of adjacent structures. There are other possible causes of injury but they are much less common. There is also some evidence that nerve growth factors may be involved. At least one factor, the neurotrophic factors, is known or postulated to be the cause of most nerve injuries. The problem is that nobody knows how and why these proteins are associated with nerve damage. If they are in the blood at all, they must be present in very low concentrations.
Nerves may be affected by many different symptoms, depending on what part of the body the nerve is damaged. Pain is the most common complaint, though it may first appear as numbness or tingling in the hands and feet. The numbness is typically located in the hands, while the tingling is typically in the feet. Other symptoms may include pain, impaired coordination, and loss of appetite.
The proportion of adults with nerve injury who require medical or surgical care is not increasing. On the contrary, the proportion of children seen for nerve injury increased between 2002-2005. This suggests that the nerve injury diagnosis could be being underreported, possibly because healthcare providers are not ask[ing]: to the patients if they sustain a nerve injury.
Nerve injury can occur in any part of the body; but is most commonly seen in the legs. Nerve injuries are the most frequent cause of paralysis in adults and children below the age of 10 years, affecting more children than adults to a greater degree. The mechanism of nerve injuries is very complex and many different types of nerve injury have been described.
Theoretically, nerve regeneration can be successful even in the presence of axon trunks that have been irreversibly crushed. However, repair of nerve injuries remains problematic. There is a limitation to the extent to which nerve growth factors and cell transplants can improve the healing of transected nerves. For most axon trunks, nerve regeneration is limited by the distance that axons can grow to before terminating. Therefore, treatment of nerve injuries generally leads to improved function, although functional recovery after such traumatic dislocations is often minimal.
Many techniques used for nerve block and nerve repair are common solutions to [pain management](https://www.withpower.com/clinical-trials/pain-management). Neuroplasty, a surgical technique where nerves are reattached to reconstruct the nerve or the muscle, is a new form of treatment. However, this treatment has been used for only a few years and there is no evidence regarding its effectiveness. The use of a peripheral nerve stimulator can cause pain and numbness in the arms or legs, which is typically temporary and disappears over a few days to weeks. Most cases of foot-drop are associated with injury to the peroneal nerve, which innervates portions of the front, back, and lower legs. One study reported that 60% of patients with foot-drop had peroneal nerve injury.
Use of a PNS in the treatment of postoperative pain is safe and effective. Further randomized and controlled clinical studies are needed to determine its long-term results and the optimal clinical applications of this technique.
Findings from a recent study demonstrated that temporary use of a peripheral nerve stimulator did not significantly improve QoL for patients with peripheral nerve injury. Thus, temporary stimulation for the relief of symptoms in such patients is unlikely to be cost-effective.
In the last 13 years new improvements have been made in both the technology and the surgical technique of the peripheral nerve stimulation. New developments are under study to verify the efficacy of the new technologies and technique that are capable of improving the functional recovery of the injured peripheral nerves. In the long term we should be able to solve a chronic problem that has gone on since the early years of nerve stimulation.
There is still a need for research focused on nerve repair. Further studies are needed to define different treatments and determine what constitutes a suitable treatment.
Peripheral nerve stimulation with a TENS unit produces few adverse effects on people with peripheral nerve injury. TENS should be considered for all patients who develop PAS for the benefit of pain relief, and the few side effects experienced relate to the temporary nature of the device.
It takes approximately one month after applying PNMS for the nerve to become inactive because of the natural healing process. PNMS is better than no treatment, and provides temporary and lasting relief. The duration of temporary relief by use of PNMS seems to be a reflection of the healing period of the nerve.