Comments on "Efficacy of Pulsed Radiofrequency or Short-Term Spinal Cord Stimulation for Acute/Subacute Zoster-Related Pain: A Randomized, Double-Blinded, Controlled Trial".

In May 2021’s issue of Pain Physician, Cheng-fu Wan and Tao Song concluded that both pulsed radiofrequency (PRF) and short-term spinal cord stimulation (stSCS) could reduce pain effectively for patients with acute/subacute zoster-related pain. Meanwhile, they found that stSCS could provide better pain relief with less analgesics and improved the quality of life more than PRF treatment (1), which demonstrated that stSCS might be an alternative option for the prevention and treatment of the postherpetic neuralgia (PHN). PHN, the most common complication of herpes zoster, could be defined as pain that is sustained for at least 90 days after the varicella-zoster virus infection, which was thought to be associated with nerve damage secondary to an inflammatory response induced by viral replication within a nerve (2). A large range of medications and methods have been applied for PHN so far, such as a lidocaine patch, capsaicin, opioids, as well as the anticonvulsants gabapentin and pregabalin. However, effective managements for PHN remained undefined. Early studies illustrated that PRF and stSCS were safe and effective methods to relieve the pain of acute/subacute zoster-related pain and PHN, which also could avoid the transition of acute HZ pain to PHN to some extent (1,3). In this study, however, the sample size was small, so the results might be biased and lack of representativeness. The follow-up time (180 days) was limited and the researchers did not discuss whether the pain recurred or worsened. Authors also failed to explain whether there was a potential relationship between the period of these 2 treatments and recurrence rates. Besides, the primary outcome measures only included the Numeric Rating Scale (NRS-11), the 36-Item Short Form Health Survey (SF-36) scores, as well as the dosage of analgesics. In the future, the length of hospital stays and economic indicators, for instance, expense of hospitalization, need be involved and analyzed. In addition, it was believed that the risk of developing PHN in the elderly was higher after trigeminal herpes zoster than after a spinal nerve herpes zoster (4); pain relief with drugs and other therapies was also less likely (5). For elderly patients with acute or recent trigeminal herpes zoster, the authors in another study (5) compared 2 different PRF modes and found that HL-PRF for gasserian ganglion neuromodulation might be a more effective treatment than standard-mode PRF. There were retrospective case series reported that spinal cord stimulation (SCS) improved the quality of life for patients with trigeminal neuropathic pain, in the field of which there still lacked prospective or controlled trials (6). Therefore, further studies on the efficacy or safety of SCS for the treatment of acute or recent trigeminal herpes zoster and PHN could be conducted. Although mass of research work was supposed to be performed, this study still provided an alternative approach of prevention and treatment for acute/subacute herpes zoster to chronic or PHN, which directed the clinical practice in some way.