Such interventions would have the potential to reduce the prevalence of chronic pain in the population .
Although certain risk factors can identify individuals who are most likely to develop chronic pain , few interventions to prevent chronic pain have been identified .
To facilitate the identification of preventive interventions , an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain .
We present general design considerations for prevention trials in population s that are at relatively high risk for developing chronic pain .
Effect of early stellate ganglion blockade for facial pain from acute herpes zoster and incidence of postherpetic neuralgia.
BACKGROUND The incidence of postherpetic neuralgia ( PHN ) has been reported to be 25 % among those over the age of 50 years treated with antiviral medication . The role of sympathetic block in its prevention remains question able . OBJECTIVES The aim of this study is to determine whether early stellate ganglion blockade for acute herpes zoster of the face will reduce the intensity and duration of acute herpetic pain , and if the blockade has the potential to prevent or reduce the incidence and /or severity of PHN . STUDY DESIGN R and omized , controlled , double blind trial . SETTING Hospital , outpatient setting . METHODS Sixty-four patients over 50 years were assigned to receive a stellate ganglion block using either 8 mL saline ( Group 1 ) or 6 mL bupivacaine 0.125 % and 8 mg dexamethasone in a total volume of 8 mL ( Group 2 ) . All procedures were performed under fluoroscopy . All patients received pregabalin in a dose of 150 mg twice daily . Acetaminophen was available as needed . Pain assessment using the visual analog scale and amount of analgesic being taken was measured at the initial visit ( basal ) , weekly for 6 weeks after the procedure and after 2 , 3 , and 6 months . Once a patient reported mild pain during the trial , pregabalin was tapered by 75 mg every other day ; the patients who succeeded in this step were recorded in each group . The time of complete resolution of pain and incidence of persistent postherpetic pain was reported . Each patient 's satisfaction was evaluated . RESULTS There was a significantly shorter duration of pain noticed in Group 2 ( P = 0.002 ) . A significantly lower incidence of PHN was encountered in Group 2 after 3 months ( P = 0.043 ) and 6 months ( P = 0.035 ) . Significantly more patient satisfaction was reported in Group 2 after 3 and 6 months . By the fourth week , 29 patients in Group 2 reported no pain . Two patients reported mild pain after 3 months which was resolved by the sixth month . In Group 1 , 22 patients reported no pain by the sixth week and 8 patients reported moderate pain after 2 and 3 months ; by the sixth month , 4 out of those 8 patients showed spontaneous remission of pain . There was a significant reduction in the total doses of pregabalin and acetaminophen  in Group 2 ( P < 0.001 ) . No serious adverse effects were reported during the study period . LIMITATIONS The sample size was determined using the incidence of PHN ( chronic pain ) as a main hypothesis . Meanwhile , this study determined the incidence of acute pain as well , which may lead to bias to the results of acute pain . CONCLUSION Early stellate ganglion blockade , in combination with an antiviral agent , is a very effective treatment modality ; it dramatically decreases the intensity of acute pain and shortens its duration and reduces the incidence of postherpetic neuralgia
Such interventions would have the potential to reduce the prevalence of chronic pain in the population .
Although certain risk factors can identify individuals who are most likely to develop chronic pain , few interventions to prevent chronic pain have been identified .
To facilitate the identification of preventive interventions , an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain .
We present general design considerations for prevention trials in population s that are at relatively high risk for developing chronic pain .