Zapping the Pain Away: Pulsed Radiofrequency for C5 Nerve Root Causalgia after Tumor Excision

Abstract Causalgia, or complex regional pain syndrome (CRPS) type II, is a challenging neuropathic pain condition often resistant to conventional treatments. Pulsed radiofrequency (PRF) has emerged as a minimally invasive intervention for managing such pain. This case report details the successful use of PRF on the C5 remnant nerve root in a patient with CRPS type II following C5 nerve sheath tumor excision. A 50-year-old woman developed severe left upper limb pain, characterized by burning, allodynia, hyperalgesia, intermittent swelling, and motor weakness after the excision of a C5 nerve sheath tumor. Conservative treatments, including medications and physiotherapy, offered minimal relief. A diagnostic block of the left C5 remnant nerve root with ropivacaine and dexamethasone resulted in a 70% temporary pain reduction, confirming the nerve root as the primary pain generator, while a stellate ganglion block was ineffective. PRF was performed on the left C5 remnant nerve root under ultrasound guidance, at 42°C for 120 s. The patient reported a 50% reduction in pain intensity, from Numeric Pain Rating Scale score 8/10–4/10, and improvement in Douleur Neuropathique 4 score 7/10–2/10 for over 12 weeks, significantly improving her quality of life and function. This case shows us that PRF of the C5 remnant nerve root successfully reduced pain, highlighting the importance of diagnostic nerve blocks for proper patient selection. By modulating pain pathways without nerve destruction, PRF offers a promising alternative when traditional therapies fail.