Differential diagnosis of intraspinal and extraspinal non-discogenic sciatica.

The aim of this study is to present a series of 11 patients with non-discogenic sciatica (NDS), and to review the diagnostic techniques of careful clinical and radiological examination. The cases include lumbar radicular herpes zoster, lumbar nerve root schwannoma, lumbar instability, facet hypertrophy, ankylosing spondylitis, sacroiliitis, sciatic neuritis, piriformis syndrome, intrapelvic mass and coxarthrosis. The pain pattern and accompanying symptoms were the major factors suggesting a non-discogenic etiology. Pelvic MRI and CT scans, and sciatic nerve magnetic resonance neurography were the main diagnostic tools for diagnosis of NDS. The treatment of choice depended on the primary diagnosis. Detailed physical examinations with special attention paid to the extraspinal causes of sciatica and to pain characteristics are the major components of differential diagnosis of NDS.