Eriksen J, Sjøgren P, Bruera E, et al. Critical issues on opioids in chronic non-cancer pain : an epidemiological study. Pain 2006 ; 125 : 172-9.
Manchikanti L, Ailinani H, Koyyalagunta D, et al. A systematic review of randomized trials of long-term opioid management for chronic non-cancer pain. Pain Physician 2011 ; 14 : 91-121.
Chaparro LE, Furlan AD, Deshpande A, et al. Opioids compared with placebo or other treatments for chronic low back pain : an update of the Cochrane Review. Spine (Phila Pa 1976) 2014 ; 39 : 556-63.