Pain characteristics of adults 65 years of age and older referred to a tertiary care pain clinic.

BACKGROUND: Reports indicate that characteristics of older adults with chronic pain may be different than those of younger persons. OBJECTIVE: To study the pain characteristics of older patients presenting to a tertiary pain clinic for the first time. METHODS: Age, sex and relative contributions of biomedical versus psychosocial variables contributing to chronic pain were investigated in patients 65 years of age and older, in comparison with younger patients, from a sample of 1242 consecutive new patients attending a tertiary care pain clinic. The presence of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision somatoform pain disorders were defined, using an explicated method of ascertaining the biomedical and psychological variables underlying the pain complaints. RESULTS: The older patients (14.7% of the total sample) had relatively more physical problems (concordant with their complaints) but fewer psychological factors contributing to disability than the younger pain patients. Musculoskeletal and neuropathic disorders affected 40.7% and 35.2% of the older patients, respectively, while several patients had more than one painful disorder. Musculoskeletal problems were more prevalent in the women, and neuropathic problems were more prevalent in the men. CONCLUSIONS: The older pain patients are a distinct group. Factors affecting the delayed presentation of older pain patients to the pain clinic and limitations of the present study are discussed.

Opioids for chronic low-back pain.

BACKGROUND: The use of opioids in the long-term management of chronic low-back pain (LBP) appears to be increasing. Despite this trend, the benefits and risks of these medications remain unclear. OBJECTIVES: To determine the efficacy of opioids in adults with chronic LBP. SEARCH STRATEGY: We electronically searched CENTRAL, CINAHL and PsycINFO to May 2006; MEDLINE and EMBASE to May 2007. We supplemented our search by reviewing references in relevant systematic reviews and identified trials. SELECTION CRITERIA: We included randomized or quasi-randomized controlled trials assessing the use of opioids (as monotherapy or in combination with other therapies) for longer than four weeks, in adults with chronic LBP. Studies were included if they compared non-injectable opioids to other treatments. Comparisons between opioids were excluded. DATA COLLECTION AND ANALYSIS: Two authors independently assessed methodological quality and extracted data onto a pre-designed form. Results were statistically pooled using RevMan 4.2. We reported on pain and function using standardized mean difference (SMD) with 95% confidence interval (95% CI) and on side effects using absolute risk difference (RD) with 95% CI. MAIN RESULTS: We included four trials. Three compared tramadol to placebo. Pooled results revealed that tramadol was more effective than placebo for pain relief, SMD 0.71 (95% CI 0.39 to 1.02), and improving function, SMD 0.17 (95% CI 0.04 to 0.30). The two most common side effects of tramadol were headaches, RD 9% (95% CI 6% to 12%) and nausea, RD 3% (95% CI 0% to 6%). One trial comparing opioids to another analgesic (naproxen) found opioids were statistically significant for relieving pain but not improving function. When re-calculated, the results were not statistically significant for either pain relief (SMD -0.58; 95% CI -1.42 to 0.26) or improving function (SMD -0.06; 95% CI -0.88 to 0.76) . AUTHORS' CONCLUSIONS: Despite concerns surrounding the use of opioids for long-term management of chronic LBP, there remain few high-quality trials assessing their efficacy. The trials in this review, although achieving high internal validity scores, were characterized by a lack of generalizability, inadequate description of study populations, poor intention-to treat analysis, and limited interpretation of functional improvement. Based on our results, the benefits of opioids in clinical practice for the long-term management of chronic LBP remains questionable. Therefore, further high-quality studies that more closely simulate clinical practice are needed to assess the usefulness, and potential risks, of opioids for individuals with chronic LBP.

Pain characteristics and demographics of patients attending a university-affiliated pain clinic in Toronto, Ontario.

BACKGROUND: Pain clinics tend to see more complex chronic pain patients than primary care settings, but the types of patients seen may differ among practices. OBJECTIVE: The aim of the present observational study was to describe the pain and demographic characteristics of patients attending a university-affiliated tertiary care pain clinic in Toronto, Ontario. METHODS: Data were collected on 1242 consecutive new patients seen over a three-year period at the Comprehensive Pain Program in central Toronto. RESULTS: Musculoskeletal problems affecting large joints and the spine were the predominant cause of pain (more prevalent in women), followed by neuropathic disorders (more prevalent in men) in patients with recognizable physical pathology. The most affected age group was in the 35- to 49-year age range, with a mean pain duration of 7.8 years before the consultation. While 77% of the Comprehensive Pain Program patients had relevant and detectable physical pathology for pain complaints, three-quarters of the overall study population also had significant associated psychological or psychiatric comorbidity. Women, in general, attended the pain clinic in greater numbers and had less apparent physical pathology than men. Finally, less than one in five patients was employed at the time of referral. CONCLUSIONS: The relevance of the data in relation to other pain clinics is discussed, as well as waiting lists and other barriers faced by chronic pain patients, pain practitioners and pain facilities in Ontario and Canada.

Ethnocultural and sex characteristics of patients attending a tertiary care pain clinic in Toronto, Ontario.

BACKGROUND: Ethnocultural factors and sex may greatly affect pain perception and expression. Emerging literature is also documenting racial and ethnic differences in pain access and care. OBJECTIVE: To define the sex and ethnocultural characteristics of patients attending a tertiary care, university-affiliated pain clinic in Toronto, Ontario. METHODS: Data were collected on 1242 consecutive, new patients seen over a three-year period at the Comprehensive Pain Program (CPP) in downtown Toronto. Data were compared with the Canada 2001 Census. RESULTS: English-speaking, Canadian-born patients constituted 58.6% of the CPP population, similar to the 2001 Canadian Census data for the Greater Toronto Area. Certain visible minority groups (Indo-Pakistani and Chinese) were significantly under-represented, while European groups were over-represented. While women outnumbered men, they presented with lower levels of physical pathology in general, particularly in certain ethnic groups. Patients from Europe (representing primarily immigrants who arrived in Canada before 1960), were older, by 10 years to 15 years, than the average CPP population, and had a much higher incidence of physical or medical disorders. CONCLUSIONS: The implications of the study and the importance of sex and ethnicity in terms of presentation to Canadian pain clinics are discussed. Future well-designed studies are needed to shed light on the role of both patients' and physicians' ethnicity and sex in pain perception and expression, decision-making regarding pain treatments and acceptance of pain treatments.

Pharmacological management of chronic neuropathic pain - consensus statement and guidelines from the Canadian Pain Society.

Neuropathic pain (NeP), generated by disorders of the peripheral and central nervous system, can be particularly severe and disabling. Prevalence estimates indicate that 2% to 3% of the population in the developed world suffer from NeP, which suggests that up to one million Canadians have this disabling condition. Evidence-based guidelines for the pharmacological management of NeP are therefore urgently needed. Randomized, controlled trials, systematic reviews and existing guidelines focusing on the pharmacological management of NeP were evaluated at a consensus meeting. Medications are recommended in the guidelines if their analgesic efficacy was supported by at least one methodologically sound, randomized, controlled trial showing significant benefit relative to placebo or another relevant control group. Recommendations for treatment are based on degree of evidence of analgesic efficacy, safety, ease of use and cost-effectiveness. Analgesic agents recommended for first-line treatments are certain antidepressants (tricyclics) and anticonvulsants (gabapentin and pregabalin). Second-line treatments recommended are serotonin noradrenaline reuptake inhibitors and topical lidocaine. Tramadol and controlled-release opioid analgesics are recommended as third-line treatments for moderate to severe pain. Recommended fourth-line treatments include cannabinoids, methadone and anticonvulsants with lesser evidence of efficacy, such as lamotrigine, topiramate and valproic acid. Treatment must be individualized for each patient based on efficacy, side-effect profile and drug accessibility, including cost. Further studies are required to examine head-to-head comparisons among analgesics, combinations of analgesics, long-term outcomes, and treatment of pediatric and central NeP.

Spinal cord stimulation for chronic pain.

BACKGROUND: Spinal cord stimulation (SCS) is a form of therapy used to treat certain types of chronic pain. It involves an electrical generator that delivers pulses to a targeted spinal cord area. The leads can be implanted by laminectomy or percutaneously and the source of power is supplied by an implanted battery or by an external radio-frequency transmitter. The exact mechanism of action of SCS is poorly understood. OBJECTIVES: To assess the efficacy and effectiveness of spinal cord stimulation in relieving certain kinds of pain, as well as the complications and adverse effects of this procedure. SEARCH STRATEGY: We searched MEDLINE and EMBASE to September 2003; the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 3, 2003); textbooks and reference lists in retrieved articles. We also contacted experts in the field of pain and the main manufacturer of the stimulators. SELECTION CRITERIA: We included trials with a control group, either randomized controlled trials (RCTs) or non-randomized controlled clinical trials (CCTs), that assessed spinal cord stimulation for chronic pain. DATA COLLECTION AND ANALYSIS: Two independent reviewers selected the studies, assessed study quality and extracted the data. One of the assessors of methodological quality was blinded to authors, dates and journals. The data were analysed using qualitative methods (best evidence synthesis). MAIN RESULTS: Two RCTs (81 patients in total) met our inclusion criteria. One was judged as being of high quality (score of 3 on Jadad scale) and the other of low quality (score of 1 on Jadad scale). One trial included patients with Complex Regional Pain Syndrome Type I (reflex sympathetic dystrophy) and the other patients with Failed Back Surgery Syndrome. The follow-up periods varied from 6 to 12 months. Both studies reported that SCS was effective, however, meta-analysis was not undertaken because of the small number of patients and the heterogeneity of the study population. REVIEWERS' CONCLUSIONS: 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.

Altered central somatosensory processing in chronic pain patients with "hysterical" anesthesia.

OBJECTIVE: The authors hypothesized that central factors may underlie sensory deficits in patients with nondermatomal somatosensory deficits (NDSD) and that functional brain imaging would reveal altered responses in supraspinal nuclei. BACKGROUND: Patients with chronic pain frequently present with NDSD, ranging from hypoesthesia to complete anesthesia in the absence of substantial pathology and often in association with motor weakness and occasional paralysis. Patients with pain and such pseudoneurologic symptoms can be classified as having both a pain disorder and a conversion disorder (Diagnostic and Statistical Manual of Mental Disorders-IV classification). METHODS: The authors tested their hypothesis with functional MRI (fMRI) of brush and noxious stimulation-evoked brain responses in four patients with chronic pain and NDSD. RESULTS: The fMRI findings revealed altered somatosensory-evoked responses in specific forebrain areas. Unperceived stimuli failed to activate areas that were activated with perceived touch and pain: notably, the thalamus, posterior region of the anterior cingulate cortex (ACC), and Brodmann area 44/45. Furthermore, unperceived stimuli were associated with deactivations in primary and secondary somatosensory cortex (S1, S2), posterior parietal cortex, and prefrontal cortex. Finally, unperceived (but not perceived) stimuli activated the rostral ACC. CONCLUSIONS: Diminished perception of innocuous and noxious stimuli is associated with altered activity in many parts of the somatosensory pathway or other supraspinal areas. The cortical findings indicate a neurobiological component for at least part of the symptoms in patients presenting with nondermatomal somatosensory deficits.