Injection of the Piriformis Muscle by Fluoroscopic and Electromyographic Guidance

Background There is not a universally accepted single technique for injection of the piriformis muscle that has validated exact placement of the needle tip within the piriformis muscle. Objective We sought a methodology that would precisely document needle placement within the piriformis muscle that is reliable, relatively uncomplicated, and reproducible. Methods Patients with piriformis syndrome underwent injections of the piriformis muscle under fluoroscopic and electromyographic guidance. This technique used electrophysiological confirmation of needle placement within the piriformis muscle and image-guided identification of the piriformis muscle with radiopaque contrast media under fluoroscopy. Results Using this methodology, injections on 17 occasions in 11 patients resulted in needle placement within the piriformis muscle.