Nerve injury, particularly when partial and particularly for certain nerves (such as the median or tibial nerve) can cause as ‘neuropathic’ pain: such cases are characterised by allodynia (burning sensation upon light touch or cooling of a particular skin area innervated by the lesioned nerve). Neuropathic pain may be associated with changes in color and perfusion of the skin area in the involved extremity as a result of failure of physiological autoregulatory mechanisms and evolve into a “chronic regional pain syndrome”. Spontaneous pain as a consequence of brachial plexus injury has been mentioned previously
Surgical exploration of the site of nerve injury may discern a remediable structural cause of pain.
Non-surgical management of neuropathic pain involves the use of drugs such as pregabalin, amitryptiline, and duloxetine and the help of psychologists and other therapists. Specialised pain management teams can bring to bear a the variety of resources.
In rare cases when extensive treatment by pain specialists has not sufficed, neuromodulative treatment such as electrical stimulation of the spinal cord may be considered.
In this method, electrodes are brought into contact directly with the posterior spinal cord. Then a test-stimulation is applied for a day or two that follows electrode placement and the patient is asked about the level of pain. If the test stimulation is effective, then a compact impulse generator is implanted in a subcutaneous pouch and connected to the previously placed electrode. These generators are equipped with batteries that last 5-10 years depending on the programming used for stimulation, after which time they require changing. Some modern generators are rechargeable using transcutaeous contact interfaces, however require quite frequent recharging.
The surgical operation is only one component of the treatment of pain from peripheral nerve lesions. Postoperative physical therapy methods such as strengthening of target muscles, exponential current stimulation to preserve muscle bulk, and hydrotherapy are all integral parts of modern treatment algorithms. Pain management may require sophisticated pharmacological and psychological measures from a specialised team.