Anaesthesia dolorosa after gamma knife radiosurgery: a cautionary insight into long-term complications

This case report describes a male patient in his 70s who developed a rare and severe complication of gamma knife radiosurgery (GKRS) following treatment for trigeminal neuralgia. While initially effective, the patient developed progressive facial numbness and intractable facial pain approximately 1 year post-treatment, resulting in a diagnosis of anaesthesia dolorosa (AD), a debilitating form of deafferentation pain marked by painful numbness. Despite multiple specialist evaluations and treatment attempts, his symptoms persisted, profoundly impairing function and quality of life. This case underscores the potential for delayed-onset, life-altering complications following GKRS, a treatment generally considered safe. It highlights the critical importance of thorough preoperative counselling, long-term follow-up and early recognition of atypical symptom evolution. As AD is rarely reported after GKRS, this case adds to the limited literature and calls for increased clinical awareness and multidisciplinary approaches to diagnosis, prevention and management of this devastating condition.