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.