Sciatic neuropathy is a mononeuropathy caused by damage to the sciatic nerve following trauma, hematoma, injections, compression or surgical complications. Consequently, symptoms such as pain, paresthesias, and neurological deficits can develop. Electromyography and nerve conduction studies help in diagnosis and provide prognostic information.
Sciatic neuropathy (SN) is a result of nerve injury or compression anywhere along the route of the nerve from the lumbosacral region to its bifurcation in the posterior aspect of the thigh. Accidental (hip fracture, dislocation, penetrating wounds) or iatrogenic (intramuscular injections) trauma, tumors, ischemia, and compression (hematomas, compression syndrome) can cause this condition   . Piriformis syndrome is another rare etiologic factor of SN. As compression neuropathy is seen during pregnancy, prolonged lithotomy position can lead to piriformis syndrome and consequently SN .
Patients with SN typically present with lower extremity pain and paresthesias. Other symptoms depend on the level at which the sciatic nerve is affected. If the lesion is proximal then genuflexion is difficult, with a loss of foot dorsiflexion (flail foot), and plantarflexion . There may be a loss of sensations if the lesion involves the posterior aspect of the thigh and the foot . Patients may be able to flex and extend their knee in hamstring sparring injuries of the nerve, although their gait will be impaired by their inability to plantarflex and dorsiflex . Injuries in the distal part of the nerve give rise to neurological deficits similar to those seen in other mononeuropathies or lumbosacral radiculopathies .
Children, when suffering from SN, present with weakness of the tibialis anterior and gastrocnemius muscles . However, SN occurs rarely in this age group.
SN workup includes a detailed history along with a thorough clinical and neurological examination which will reveal a weakness of the tibialis anterior and/or gastrocnemius muscle. It is important to differentiate between SN, radiculopathies, and plexopathies as they all present with identical symptoms.
However electrodiagnostic tests such as electromyography and nerve conduction velocity test (NCV) are necessary to confirm the diagnosis and to provide information regarding prognosis . They are also useful if the examination findings are inconclusive or if sensory deficits cannot be elicited e.g. in children. NCV are normal in radiculopathies but altered or abnormal in SN . Motor unit amplitude, arrangement, and duration are useful to determine whether SN has been long-standing . For the diagnosis of SN in children, electrophysiologic findings along the peroneal as well as the tibial and sural nerve distribution should be performed with or without electromyography in the muscles innervated by the tibial nerve .
Magnetic resonance imaging (MRI) or neurography and ultrasonography are some of the radiological tests performed in the workup of SN. Neuropathy findings on MRI include expansion of the nerve with variation in its course and elevated signal intensity and contrast enhancement. In patients with sciatic nerve compression, there may be edema in the vicinity of the nerve around the ischial tuberosity  MRI can also help to detect other lesions like tumors.