“…In some epidemiological studies, there was no operational definition a priori, even though patients could have their pain uncontrolled or were not receiving opioids [9,10]. For example, background pain intensity was severe-maximal in more than half of patients, and differently from what has been observed by others [9,11], surprisingly, the intensity of baseline pain was higher in patients without BTcP. In other studies, most patients had uncontrolled background pain, were receiving nonopioid analgesics or weak opioids, or were unsatisfied with their pain control [11,12].…”