Efficacy of Transcutaneous Pulsed Radiofrequency in Postherpetic Neuralgia

Postherpetic neuralgia (PHN) is a chronic pain syndrome that may be resistant to treatment and can lead to physical and social disability as well as psychological disturbances, persisting for years in some patients. Varicella zoster virus remains latent in the sensory neurons of individuals who have previously had chickenpox. Reactivation of the latent virus results in herpes zoster. Herpes zoster typically begins with dermatomal pain, followed within a few days by the development of characteristic dermatomal skin rashes. These cutaneous lesions usually resolve within 2-4 weeks; however, pain may persist even after the rash has healed.

There is variability in the literature regarding the definition of PHN. The development of PHN is associated with increased central neuronal sensitization, reduced inhibitory neuronal function, inflammation and nerve injury in the peripheral nervous system, and abnormal neural transmission following nerve damage. PHN is the most common complication of herpes zoster and occurs in approximately 9-19% of affected patients. Its incidence increases with age, occurring in about 2% of patients under 50 years of age, approximately 20% of those over 50 years, and nearly 35% of patients over 80 years of age.

Various treatment options are available for the management of PHN-related pain, including pharmacological and interventional approaches. Systemic agents include tricyclic antidepressants, calcium channel alpha-2-delta ligands, serotonin-norepinephrine reuptake inhibitors, and opioids, while topical treatments include lidocaine and capsaicin. Interventional treatment options for PHN include epidural and intrathecal injections, sympathetic nerve blocks, erector spinae plane block, subcutaneous injections, and spinal cord stimulation.