Neuralgia refers to severe, sharp pain occurring along the course of a nerve. This diagnostic code refers to the external popliteal nerve, a mixed sensory and motor nerve that innervates the extensor muscles of the ankle and toes, and the abductor of the foot. Sensation is transmitted from portions of the leg including the outer side, the front lower third, and the instep, and the dorsal surface of the four inner toes.

Neuralgia may be caused by pressure on the nerve trunks, faulty nerve nutrition, toxins, or inflammation. Damage to the nerve may occur from wounds in the region of the knee or in the sciatic nerve trunk in the thigh. Tumors or cysts at the head of the fibula may compress the nerve and produce foot drop and burning pain along the lateral side of the leg.

Neuralgia results in pain in the affected extremity. Faulty nutrition to the nerve may cause the development of changes in leg muscle size (trophic changes), swelling (from toxins or inflammation), and local cyanosis and lack of sweat secretion (from vasomotor changes). Compression of the nerve, such as from a tumor or cyst at the head of the femur, will cause burning pain on the lateral aspect of the leg, ankle, and foot.

Peripheral nerve examination may include: nerve conduction tests; electromyography; computed tomography (CT) scan; magnetic resonance imaging (MRI); muscle-strength testing; deep tendon reflexes (DTR); sensory testing; and gait examination.

The usual treatment for the condition consists of physiotherapy and use of a foot brace. An exception is chronic peroneal compression at the fibular head because fibrosis retards nerve regeneration. Patients should avoid extended leg crossing, prolonged sitting on a toilet, or using unusual positions, such as yoga sitting. The usual treatment consists of a splint that supports the ankle and the foot, and range of motion (ROM) exercises. If the nerve does not show signs of regeneration, it may have to be explored and freed from adhesions. Other therapies that may be used are electrical stimulation, ultrasound, analgesics, and massage. If a tumor or cyst causes compression and pain, then relief of symptoms may be obtained by excision of the mass.

Pressure neuritis and resulting neuralgia may be temporary or permanent depending on the amount and time of exposure to injury. If recovery does not occur, then surgical exploration may be necessary.

• If the Veteran is a former prisoner of war and was interned or detained for not less than 30 days, this disease shall be service connected if manifest to a degree of disability of 10% or more at any time after discharge or release from active military, naval, or air service even though there is no record of such disease during service, provided the rebuttable presumption provisions of 38 CFR 3.307 are also satisfied [38 CFR 3.309(c) Disease subject to presumptive service connection].

• If the Veteran was exposed to an herbicide agent during active military, naval, or air service, this disease shall be service-connected if the requirements of 38 CFR 3.307(a)(6) are met even though there is no record of such disease during service, provided further that the rebuttable presumption provisions of 38 CFR 3.309(e). Disease subject to presumptive service connection.

• This disability shall be granted service connection although not otherwise established as incurred in or aggravated by service if manifested to a compensable degree within the applicable time limits under 38 CFR 3.307 following service in a period of war or following peacetime service on or after January 1, 1947, provided the rebuttable presumption provisions of 38 CFR 3.307 are also satisfied.  38 CFR 3.309(a)

• Neuralgia, cranial or peripheral, characterized usually by a dull and intermittent pain, of typical distribution so as to identify the nerve, is to be rated on the same scale, with a maximum equal to moderate incomplete paralysis. See nerve involved for diagnostic code number and rating. Tic douloureux, or trifacial neuralgia, may be rated up to complete paralysis of the affected nerve.  38 CFR 4.124 Neuralgia, cranial or peripheral.

• With the exceptions noted, disability from the following diseases and their residuals may be rated from 10 percent to 100 percent in proportion to the impairment of motor, sensory, or mental function. Consider especially psychotic manifestations, complete or partial loss of use of one or more extremities, speech disturbances, impairment of vision, disturbances of gait, tremors, visceral manifestations, etc., referring to the appropriate bodily system of the schedule. With partial loss of use of one or more extremities from neurological lesions, rate by comparison with the mild, moderate, severe, or complete paralysis of peripheral nerves] 38 CFR 4.124a Schedule of ratings—neurological conditions and convulsive disorders