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 .
A Multicenter, Randomized, Controlled Study Evaluating Preventive Etanercept on Postoperative Pain After Inguinal Hernia Repair
BACKGROUND :  Chronic postsurgical pain ( CPSP )  affects between 5 % and 70 % of surgical patients , depending on the surgery . There is no reliable treatment for CPSP , which has led to an increased emphasis on prevention . In this study , we sought to determine whether preventive etanercept can decrease the magnitude of postoperative pain and reduce the incidence of CPSP . METHODS : We performed a multicenter , r and omized study in 77 patients comparing subcutaneous etanercept 50 mg administered 90 minutes before inguinal hernia surgery with saline .  Patients , surgeons , anesthesiologists , the injecting physician , nursing staff , and evaluators were blinded . The primary outcome measure was a 24-hour numerical rating scale pain score . Secondary outcome measures were postanesthesia care unit pain scores , 24-hour opioid requirements , time to first analgesic , and pain scores recorded at 1 month , 3 months , 6 months , and 12 months . RESULTS : Mean 24-hour pain scores were 3.3 ( 95 % confidence interval [ CI ] , 3.2–4.6 ) in the etanercept and 3.9 ( 95 % CI , 2.6–4.0 ) in the control group ( P = 0.22 ) . The mean number of analgesic pills used in the first 24 hours was 4.0 ( SD , 2.8 ) in the treatment versus 5.8 ( SD , 4.2 ) in the control group ( P = 0.03 ) . At 1 month , 10 patients ( 29 % ) in the treatment group reported pain versus 21 ( 49 % ) control patients ( P = 0.08 ) . The presence of pain at 1 month was significantly associated with pain at 3 months ( hazard ratio , 0.74 ; 99 % CI , 0.52–0.97 ; P = 0.03 ) . CONCLUSION : Although preventive etanercept was superior to saline in reducing postoperative pain on some measures , the effect sizes were small , transient , and not statistically significant . Different dosing regimens in a larger population should be explored in future studies
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 .