Ultrasound-guided trigger point injection for piriformis syndrome in the emergency department.

Piriformis syndrome, a myofascial pain disorder characterized by deep gluteal pain that radiates to the ipsilateral lower back and/or posterior thigh, is an underreported cause of low back pain frequently misdiagnosed in the emergency department (ED). Often refractory to oral pain medications, this syndrome can be debilitating. Ultrasound-guided trigger point injection of the piriformis muscle can treat piriformis syndrome, but no previous reports exist in the emergency medicine literature. This case series describes 2 patients who presented to our emergency department with low back pain and were diagnosed with piriformis syndrome. Both patients received an ultrasound-guided trigger point injection of the affected piriformis muscle with a significant reduction of pain at 15 minutes and 48 hours after the procedure.