CLINICAL REPORTS Nerve Stimulator-Guided Repetitive Paravertebral Block for Thoracic Myofascial Pain Syndrome Zoher M. Naja, MD*; Mohamad A. Al-Tannir, DMD, MPH † ; Ahed Zeidan, MD ‡ ; Mariam El-Rajab, MD § ; Fouad Ziade, PhD ¶ ; Anis Baraka, MD** *Department of Anesthesia and Pain Medicine, Makassed General Hospital, Beirut; † Research Unit, Makassed General Hospital, Beirut; ‡ Department of Anesthesiology, Sahel General Hospital, Beirut, Lebanon; § Paediatric Intensive Care, Makassed General Hospital, Beirut; ¶ Faculty of Public Health, Lebanese University, Beirut; **Department of Anesthesia, American University of Beirut Medical Center, Beirut, Lebanon  Abstract: Myofascial pain syndrome (MPS) may persist for many years and is often refractory to traditional thera- peutic approaches including pharmacotherapy, focal tender- ness infiltration by local anesthetic and corticosteroids, physical therapy and behavioral modification. This report describes three cases of MPS following coronary artery bypass graft, inadequate positioning during abdominal hysterectomy, and excessive physical effort refractory to conventional therapeutic approaches. Three patients were successfully treated with repeated nerve stimulator-guided paravertebral block using a mixture of bupivacaine and clonidine. Physical examinations including a complete neurological assessments were unremarkable. Relevant diagnostic imaging (X-ray, magnetic resonance imaging, computed tomography) and laboratory evaluations also failed to dem- onstrate any significant structural disorders or systemic dis- eases that might have been responsible for their pain. Nerve stimulator-guided paravertebral block was performed at the dermatomes corresponding to the thoracic myofascial pain region. Each point was injected with 4 mL of the local anes- thetic solution. If the pain returned, a second paravertebral block was performed. The three patients were pain-free over a follow-up period up to 2 years. Our report suggests that nerve stimulator-guided paravertebral blockade could be a useful treatment for MPS refractory to traditional therapeu- tic approaches.  Key Words: myofascial pain syndrome, neuroplasticity, paravertebral block, trigger point, clonidine. INTRODUCTION Myofascial pain syndrome (MPS) is a chronic muscle pain disorder in one or more muscles associated with focal tenderness called trigger points. 1,2 The term Myo- fascial Trigger Point (MTrP) is defined as a focal tender- ness in a taut band of skeletal muscle that is painful on compression and responsible for the pain in the zone of Address correspondence and reprint requests to: Zoher Naja, MD, Head of Anesthesia Departments, Makassed General Hospital, PO Box: 11–6301 Riad El-Solh 11072210, Beirut, Lebanon. Tel: 961 3 377064; Fax: 961 1 636941; E-mail: zouhnaja@yahoo.com. Submitted: March 13, 2007; Revision accepted: June 14, 2007 DOI. 10.1111/j.1533-2500.2007.00149.x © 2007 World Institute of Pain, 1530-7085/07/$15.00 Pain Practice, Volume 7, Issue 4, 2007 348–351