The Clinical Effect And Influence Factors Of Treatment For Postherpetic Neuralgia(PHN) By Injecting Doxorubicin To Dorsal Root Ganglion Neurons

Postherpetic neuralgia is a common and potentially debilitating complication of herpes zoster that is difficult to manage. It is characterized by pain or dysesthesia that persists after resolution of the rash. Postherpetic neuralgia occurs in10%～27%of patients with herpes zoster, and Some studies have shown that: the risk for development of this complication increases with advancing age., more than50years, the incidence rate of40%, more than75years of age can be high up to75%.The severity of pain in PHN ranges from mild to excruciating, and it can be constant, intermittent, or triggered by such stimuli as clothes touching the skin. Although allodynia affects45%to55%of patients with herpes zoster, it may affect as many as90%of those with PHN. The pain associated with herpes zoster or PHN may last for a few minutes or occur as chronic pain. The duration of PHN has been found to be inconsistent, ranging from30days to6months or longer after rash onset. In some cases, the pain persists for years.Dorsal root ganglion (DRG) cells are the primary afferent neurons of algaesthesis of trunk and extremities. DRG connects the spinal cord with internal and external environment of the organism. It not only transmits and accommodates sensations but also accepts and conveys nociception of the organism, so it plays an important role in the origination and maintenance of neuropathologic pain.Adriamycin, a broad-spectrum anthracycline antibiotic and anticancer therapeutic agent, has obvious neurotoxic effect and autofluorescence. In the recent years, it was demonstrated that intravenous injection adrinmycin can selective destroy the PNS sensory ganglion, it also cause the DRG cells necrosis but not apoptosis. Also it has highly affinity to the dorsal root ganglion and result in the degeneration of the DRG cells. So it was used in the clinical to treat the neuropathic pain which was named selective chemo-ganglionectomy.Objective:To analysis the clinical effect and influence factors of treatment for postherpetic neuralgia (PHN) by injecting doxorubicin to dorsal root ganglion neurons. Methods:65patients selected by a random method were divided into three groups:short term (<1years), medium term (1-3years) and long-term (>3years). Paravertebral injections to dorsal root ganglion were guided by imaging, the comprehensive evaluation of treatment effect was evaluated using a simplified pain scale (Short-form McGill Pain Questionnaire, SF-MPQ), and then the pations were follow-up, evaluated of pain degree and duration of sleep and other symptoms, and analysed influence factors of treatment. Results:SF-MPQ before treatment was21.90±4.98. SF-MPQ after1weeks of treatment (9.78±1.35) and follow-up (6.95±0.97) scores were significantly reduced compared with before treatment, there were significant differences (P<0.01); Sleep time (3.09±0.29h)increased. But, there were no difference between short, medium, long term groups(9.78±1.35,9.66±1.25,9.57±1.31in each group). Conclusion:The interventional treatment of neuralgia after herpes zoster by injecting doxorubicin to dorsal root ganglion is a safe, effective treatment method. The influence factors of treatment effect included age older, the long time of posthepetic neuralgia, immunocompromised factor.