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 .
Perioperative ketamine does not prevent chronic pain after thoracotomy
Thoracotomy is often responsible for chronic pain , possibly of neuropathic origin . To confirm pre clinical studies , the preventive effects of perioperative ketamine were tested in a r and omized , double‐blind , placebo‐controlled clinical trial on persistent neuropathic pain after thoracotomy . Eighty‐six patients scheduled for thoracotomy under st and ardised general anaesthesia were r and omised to receive either ketamine ( 1mgkg−1 at the induction , 1mgkg−1h−1 during surgery , then 1mgkg−1 during 24h ; n=42 ) or normal saline ( n=44 ) . Postoperative analgesia included a single dose of intrapleural ropivacaine , intravenous paracetamol and nefopam , and patient‐controlled intravenous morphine . Vital parameters and analgesia were recorded during the 48 first postoperative hours . Seventy‐three patients were followed up . The patient 's chest was examined 1–2 weeks , 6 weeks and 4 months after surgery . At the last two observations , spontaneous pain score over a one‐week period ( visual analogue scale ) , neuropathic pain score ( NPSI ) , and intake of analgesics , were assessed . No drug affecting neuropathic pain ( except opiates ) was given during the follow‐up . Two patients in each group were lost to follow‐up after the 6 week visit . Ketamine  improved immediate postoperative pain , but the groups were similar in terms of neuropathic pain and intake of analgesics , 6 weeks ( NPSI score : ketamine : 1.25 [ 0–4.125 ] ; placebo : 1 [ 0–4 ] ) and 4 months after surgery . Thus , ketamine given in 24‐h infusion failed to prevent chronic neuropathic pain after thoracotomy . Other perioperative preventive long‐lasting treatments or techniques could be tested in this context
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 .