Probable cervical midline epidural septum complicating the treatment of a patient with upper extremity sympathetically maintained pain

We present a woman who developed left arm sympathetically maintained pain (SMP, or "shoulder-hand syndrome") as a result of brachial plexus injury. After confirmatory diagnosis with both stellate local anesthetic block and intravenous phentolamine infusion, the patient had a cervical epidural catheter placed and a local anesthetic infusion started. After numerous unilateral blocks were obtained, a cervical epidurogram demonstrated a probable cervical midline epidural septum. Catheter placement was adjusted, and a successful chemical sympathectomy was performed for 6 days. This resulted in significant relief of the patient's shoulder pain as well as almost complete resolution of the patient's left arm SMP symptoms. This case represents, to our knowledge, the first documentation of the use of phentolamine for the diagnosis of SMP secondary to pathology at a site proximal to that of symptomatology, as well as the first documentation of presumptive cervical midline epidural septum.