Abstract
Piriformis muscle syndrome is a condition that causes direct muscle pain around piriformis muscle or sciatica from irritated sciatic nerve and the diagnosis remains debatable. The main treatment is symptomatic relief from conservative therapy such as medication and piriformis stretching exercise, and various therapeutic injections including local anesthetic, corticosteroid, botulinum toxin can be considered for diagnostic and therapeutic purposes. In this case, a 54-year-old male who had sciatica and gait disturbance showed piriformis muscle hypertrophy in the pelvis MRI. From imaging studies, electrodiagnostic study and physical examination, he was diagnosed with piriformis muscle syndrome. He underwent trigger point injection and botulinum toxin injection into the piriformis muscle, and pain and gait disturbance significantly improved. This case reports a case of piriformis muscle syndrome with clinical symptom of gait disturbance, which was improved by botulinum toxin injection.