The acknowledgment of pain as a pathologic entity in its own right remains debated. Notwithstanding the data showing the burden of pain as a disease, an ultimate recognition of the pathologic nature of this condition is lacking. In this study, we analyze the notion of pain as a disease through an historical overview of its several conceptualizations and report the main evidence supporting this notion. We believe that a clear definition of pain as a disease is necessary, especially considering the enormous global burden of this condition. Indeed, the recognition of pain as a definite pathologic state is crucial to raise awareness about this neglected global health problem and to promote the exploration of new specific therapeutic approaches.

Phantom limb syndrome (PLS) is common after limb amputations, involving up to 90% of amputees. Although many different therapies have been evaluated, none has been found to be highly effective. Therefore, we evaluated the efficacy of a prolonged perineural infusion of a high concentration of local anesthetic solution in preventing PLS. A perineural catheter was placed immediately before or during surgery in 71 patients undergoing lower extremity amputation. A continuous infusion of 0.5% ropivacaine was started intraoperatively at 5 mL/h using an elastomeric (nonelectronic) pump, and continued for 4 to 83 days after surgery. PLS was evaluated on the first postoperative day and then 1, 2, 3, and 4 weeks, and 3, 6, 9, and 12 months after surgery. To evaluate the presence and severity of PLS while the patient was receiving the ropivacaine infusion, it was discontinued for 6 to 12 hours before each assessment period (i.e., until the sensation in the extremity returned). The severity of phantom limb and stump pain was assessed using a 5-point verbal rating scale (VRS), with 0 = no pain to 4 = intolerable pain, and “phantom” sensations were recorded as present or absent. If the VRS score was >1 or significant phantom sensations were present, the ropivacaine infusion was immediately restarted at 5 mL/h. If the VRS score remained at 0 to 1 and the patient had not experienced phantom sensations for 48 hours, the infusion was permanently discontinued and the catheter was removed. Median duration of the local anesthetic infusion was 30 days (95% confidence interval, 25–30 days). On postoperative day 1, 73% of the patients complained of severe-to-intolerable pain (visual analog scale >2). However, the incidence of severe-to-intolerable phantom limb pain was only 3% at the end of the 12-month evaluation period. At the end of the 12-month period, the percentage of patients with VRS pain scores were 0 = 84%, 1 = 10%, 2 = 3%, 3 = 3%, and 4 = none. However, phantom limb sensations were present in 39% of patients at the end of the 12-month evaluation period. All patients were able to manage the elastomeric catheter infusion system at home. Use of a prolonged postoperative perineural infusion of ropivacaine 0.5% seems to be an effective therapy for the treatment of phantom limb pain and sensations after lower extremity amputation.

Chronic pain is nowadays used as an umbrella term referring to a wide range of clinical conditions, such as fibromyalgia, migraine, or long-standing pain states without actual known causes. However, labeling a patient’s clinical condition with the term “chronic pain”, when dealing with pain lasting longer than 3 months, might be misleading. This paper aims at analyzing the possible pitfalls related to the use of the term “chronic pain” in the clinical field. It appears, indeed, that the term “chronic pain” shows a semantic inaccuracy on the basis of emerging scientific evidences on the pathogenesis of different long-standing pain states. The major pitfalls in using this label emerge in clinical settings, especially with patients having a biomedical perspective on pain or from different cultures, or with healthcare providers of other medical specialties or different disciplines. A label solely emphasizing temporal features does not help to discern the multifaceted complexity of long-standing pain states, whose onset, maintenance and exacerbation are influenced by a complex and interdependent set of bio-psycho-social factors. Thus, finding a more meaningful name might be important. We call upon the necessity of bringing awareness and implementing educational activities for healthcare providers, as well as for the public, on the biopsychosocial approach to assess, prevent and care of chronic pain. Further research on the etiopathogenetic processes of chronic pain states is also required, together with examinative diagnostic methods, to individuate the most appropriate label(s) representing the complex long-standing pain states and to avoid adopting the term “chronic pain” inappropriately.

Background: To assess the adverse effects of transdermal opiates treating moderate-severe cancer pain in comparison with slow release oral morphine. Methods: A systematic review of the literature in the MEDLINE and EMBASE databases from 1966 to June 2007 was independently performed by two authors. All phase 3 randomized trials comparing transdermal opiates and slow-release oral morphine in the treatment of moderate–severe cancer pain were considered eligible and included in the analysis. The primary end point was the overall adverse effects odds ratio (OR); secondary end points were the overall gastrointestinal adverse effects, constipation, nausea, somnolence, patients' preference, and trial withdrawal. Heterogeneity was analyzed using the Mantel-Haenszel test, and outcome analysis was performed using a random effect model; an α error lower than 5% was assumed as statistically significant. Results: Four trials met the selection criteria. The safety of transdermal opiates (fentanyl and buprenorphine) and slow-release oral morphine was analyzed in 425 patients. A significant difference in favor of transdermal opiates was observed for constipation (OR = 0.38, p < 0.001), and patients' preference (OR = 0.43, p = 0.014, in the three trials investigating transdermal fentanyl). No significant differences were observed for overall adverse effects, overall gastrointestinal adverse effects, overall neurologic adverse effects, nausea, somnolence, hypoventilation, trial withdrawal, and changes in opiate treatments. Conclusion: Although no difference in the overall adverse effect profile exists between transdermal opiates and slow release oral morphine, the difference in some adverse effects (mainly constipation) seems to favor transdermal opiates in the preference of patients with moderate-severe cancer pain.

Fibromyalgia (FM) is a serious chronic pain syndrome, characterised by muscle and joint stiffness, insomnia, fatigue, mood disorders, cognitive dysfunction, anxiety, depression and intestinal irritability. Irritable Bowel Syndrome (IBS) shares many of these symptoms, and FM and IBS frequently co-exist, which suggests a common aetiology for the two diseases. The exact physiopathological mechanisms underlying both FM and IBS onset are unknown. Researchers have investigated many possible causes, including alterations in gut microbiota, which contain billions of microorganisms in the human digestive tract. The gut-brain axis has been proven to be the link between the gut microbiota and the central nervous system, which can then control the gut microbiota composition. In this review, we will discuss the similarities between FM and IBS. Particularly, we will focus our attention on symptomatology overlap between FM and IBS as well as the similarities in microbiota composition between FM and IBS patients. We will also briefly discuss the potential therapeutic approaches based on microbiota manipulations that are successfully used in IBS and could be employed also in FM patients to relieve pain, ameliorate the rehabilitation outcome, psychological distress and intestinal symptoms.