This study examines the prevalence and efficacy of treating chronic back pain with opioids and assess its association with addiction. The authors found that opioid use was common and that such drugs me be efficacious for shot-term pain relief but that no data was available for long-term efficacy.  The study also found that substance abuse disorders are common among patients taking opioids for back pain and that aberrant medication-taking behavioral occurs in up to 24 percent of cases. 

Martell, B. A., O'Conner, P. G., Kerns, R. D. et al. (2007). Systematic review: opioid treatment for chronic back pain: prevalence, efficacy, and association with addiction. Annals of Internal Medicine, 146(2): 116-127. http://www.annals.org/cgi/content/abstract/146/2/116

Authors:  Bridget A. Martell, Patrick G. O'Connor, Robert D. Kerns, William C. Becker, Knashawn H. Morales, Thomas R. Kosten, David A. Fiellin