Background: Patients presenting with facial pain often have ineffective pain relief with medical therapy. Cases refractory to medical management are frequently treated with surgical or minimally invasive procedures with variable success rates. We report on the use of ultrasound-guided trigeminal nerve block via the pterygopalatine fossa in patients following refractory medical and surgical treatment. Objective: To present the immediate and long-term efficacy of ultrasound-guided injections of local anesthetic and steroids in the pterygopalatine fossa in patients with unilateral facial pain that failed pharmacological and surgical interventions. Setting: Academic pain management center. Design: Prospective case series. Methods: Fifteen patients were treated with ultrasound-guided trigeminal nerve block with local anesthetic and steroids placed into the pterygopalatine fossa. Results: All patients achieved complete sensory analgesia to pin prick in the distribution of the V2 branch of the trigeminal nerve and 80% (12 out of 15) achieved complete sensory analgesia in V1, V2, V3 distribution within 15 minutes of the injection. All patients reported pain relief within 5 minutes of the injection. The majority of patients maintained pain relief throughout the 15 month study period. No patients experienced symptoms of local anesthetic toxicity or onset of new neurological sequelae. Limitations: Prospective case series. Conclusion: We conclude that the use of ultrasound guidance for injectate delivery in the pterygopalatine fossa is a simple, free of radiation or magnetization, safe, and effective percutaneous procedure that provides sustained pain relief in trigeminal neuralgia or atypical facial pain patients who have failed previous medical interventions. Key words: Trigeminal nerve, ultrasound-guided, atypical facial pain, trigeminal neuralgia, tic douloureux. Pain Physician 2013; 16:E537-E545 Prospective Case Series Ultrasound-Guided Trigeminal Nerve Block via the Pterygopalatine Fossa: An Effective Treatment for Trigeminal Neuralgia and Atypical Facial Pain From: Northwestern University, Feinberg School of Medicine, Chicago, IL Address Correspondence: Mark C. Kendall, MD Northwestern University Feinberg School of Medicine Chicago, IL E-mail: m-kendall@northwestern.edu Disclaimer: There was no external funding in the preparation of this manuscript. Conflict of interest: Each author certifies that he or she, or a member of his or her immediate family, has no commercial association, (i.e., consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might post a conflict of interest in connection with the submitted manuscript. Manuscript received: 03-18-2013 Revised manuscript received: 04-29-2013 Accepted for publication: 04-30-2013 Free full manuscript: www.painphysicianjournal.com Antoun Nader, MD, Mark C. Kendall, MD, Gildasio S. De Oliveira Jr, MD, Jeffry Q. Chen, MD, Brooke Vanderby, MD, Joshua M. Rosenow, MD, and Bernard R. Bendok, MD www.painphysicianjournal.com T rigeminal neuralgia, also known as tic douloureux or suicide disease, is a chronic neuropathic pain syndrome that primarily involves the mandibular branch (V2) of the fifth cranial nerve (1,2). It is the most common form of neuralgia in adults (> 40 years of age) with a prevalence of 5 per 100,000, most frequently occurring in women over the age of 40 (3). The typical clinical presentation of Pain Physician 2013; 16:E537-E545 • ISSN 2150-1149