C hronic non-cancer-related pain (CNCP) includes chronic pain of a nociceptive or neuropathic nature with variable influence by psychological and socioenvironmental factors. Opioids are the most potent analgesics available and are well established for the treatment of severe acute, 1 surgical 2 and cancer pain.3 However, their use to ameliorate CNCP is still controversial because of the side effects of opioids, the physical tolerance they build up (with the related withdrawal reactions and possibility of addiction) and anxiety over disapproval by regulatory bodies. 4The prevalence of CNCP varies according to the type of pain and the population studied. A study conducted in the United Kingdom in a community in the greater London area to quantify the prevalence of chronic pain found that 46.5% of the general population reported chronic pain; low-back problems and arthritis were the leading causes.5 A recent epidemiological study in Denmark 6 found that nearly 130 000 adults, corresponding to 3% of the Danish population, regularly used opioids. CNCP had a prevalence of 19%, and 12% of those who had CNCP used opioid medications.The objectives of this review were 4-fold: to determine the efficacy of opioids for CNCP compared with placebo; to compare the effectiveness of opioids for CNCP with that of other drugs; to identify categories of CNCP with better response to opioids; and to determine the most common side effects and complications of opioid therapy for CNCP, including incidences of opioid addiction and sexual dysfunction. MethodsWe followed the QUOROM guidelines for reporting metaanalyses of randomized controlled trials.7 We searched the literature up to May 2005 through the OVID interface: MEDLINE (from 1960), EMBASE (from 1988), the Cochrane Database of Systematic Reviews, the Cochrane Controlled Trials Register (CENTRAL), the ACP Journal Club and DARE. We also reviewed the reference lists in the articles, reviews and textbooks retrieved. Our search strategies for MEDLINE and EMBASE are available online as Appendix 1 and Appendix 2, respectively (all appendices for this article are available at www.cmaj.ca /cgi/content/full/174/11/1589/DC1). A single reviewer (J.A.S.) ran the electronic searches and entered the data into Reference Manager 10, removing all duplicates.Each of 2 independent reviewers (A.D.F., J.A.S.) screened Methods: This meta-analysis was carried out with these objectives: to compare the efficacy of opioids for CNCP with other drugs and placebo; to identify types of CNCP that respond better to opioids; and to determine the most common side effects of opioids. We searched MEDLINE, EMBASE, CENTRAL (up to May 2005) and reference lists for randomized controlled trials of any opioid administered by oral or transdermal routes or rectal suppositories for CNCP (defined as pain for longer than 6 mo). Extracted outcomes included pain, function or side effects. Methodological quality was assessed with the Jadad instrument; analyses were conducted with Revman 4.2.7.Results: Included were 41 randomized tr...

Although there is limited evidence in favour of SCS for Failed Back Surgery Syndrome and Complex Regional Pain Syndrome Type I, more trials are needed to confirm whether SCS is an effective treatment for certain types of chronic pain. In addition, there needs to be a debate about trial designs that will provide the best evidence for assessing this type of intervention.

Spinal cord stimulation (SCS) is one of the most effective modalities for management of refractory neuropathic pain unresponsive to conservative therapies. The SCS has been successful in providing analgesia, improving function, and enhancing quality of life for patients suffering from chronic pain conditions such as failed back surgery syndrome, complex regional pain syndrome, ischaemic and phantom limb pain, and coronary artery disease. This technique has proven to be cost effective in the long term despite its high initial cost. In this review article, we discuss the history of SCS development, mechanism of action, and indications for SCS.

Oral methadone is used for various noncancer pain syndromes, at different settings and with no prescription pattern that could be identifiable. Starting, maintenance, and maximum doses showed great variability. The figure of 59% effectiveness of methadone should be interpreted very cautiously, as it seems overrated due to the poor quality of the uncontrolled studies and their tendency to report positive results. The utilization of oral methadone for noncancer pain is based on primarily uncontrolled literature. Well-designed controlled trials may provide more accurate information on the drug's efficiency in pain syndromes and in particular neuropathic pain.

RESUMENLas microalgas han sido usadas como fuente de pro ductos bioquímicos con un alto valor agregado. Esto plantea la necesidad de realizar procesos que sean rentables y con una alta calidad. El uso de sistemas continuos para estos procesos es una buena opción. El objetivo de esta investigación es realizar una pro puesta de diseño de un sistema continuo para un fotobiorreactor Airlift a escala laboratorio, manejan do variables de diseño como los flujos de entrada y salida, el diámetro de la manguera, el tiempo de retención de los tanques de almacenamiento y la po tencia de las bombas. El método matemático parte de los balances de masa y energía, que permiten relacionar estas variables con valores ya definidos para este sistema; como resultado, además de so lucionar estas variables de diseño, permitió definir y delimitar las diferentes partes y componentes del sistema continuo.Palabras clave: microalgas, sistema continuo, variables de diseño, balances de masa, balances de energía. Aceptado: noviembre 24 de 2016 ABSTRACTMicroalgae has been used as a source for biochemi cal compounds with a high added value. It implies the need for developing profitable processes with high quality. A continuous system is a good option to be used to improve that kind of process. The objective of this research was to propose a design of a continu ous system for an Airlift photobioreactor in a labora tory scale, by means of design variables such as inlet and outlet flows, diameter of the hosepipe, retention time in the storage tanks and power of the pump. The mathematical method begins with mass and energy balances that allowed relating these variables with values already defined for this system. As a result, with these balances not only was it possible to solve these design variables, but it also allowed defining and delimiting the different parts and components of the continuous system.