Lumbosacral plexopathies: Etiology, frequency, and electrodiagnostic localization

OBJECTIVE: Lumbosacral plexopathies (LSP) may occur as a result of trauma, radiation, neoplastic invasion, or diabetes mellitus, or they may be idiopathic. METHODS: We retrospectively analyzed relative frequencies of different LSP causes and their localizations and compared their electrophysiologic findings. RESULTS: A retrospective review of 34 patients' charts showed the following: idiopathic (n = 12, 35.3%), trauma (n = 9, 26.4%), radiation (n = 9, 26.4%), and diabetes mellitus (n = 4, 11.8%). Although all patients had significant weakness, sensory symptoms or deficits were present in only 44.1% of the patients. Twelve (35.2%) patients had bilateral lumbosacral plexus involvement. The majority of the patients (66.7%) in the radiotherapy group presented with bilateral involvement. Panplexopathy was the most frequent localization. The peroneal branch of the sciatic nerve was the most commonly involved nerve. Needle electromyography showed abnormal spontaneous denervation potentials in 31 (91.2%) patients. Myokymia was only present in the radiation therapy group. CONCLUSIONS: Idiopathic LSP is the most common type followed by radiation and diabetic plexopathy.