Pain expectations in neuropathic pain: Is it best to be optimistic?

BACKGROUND: Pain expectancy may be an important variable that has been found to influence the effectiveness of treatments for pain. Much of the literature supports a self-fulfilment perspective where expectations for pain relief predict the actual pain experienced. However, in conditions such as neuropathic pain (NeP) where pain relief is difficult to attain, expectations for pain relief could be unrealistic. The objective of this study was to investigate the relationship between realistic/unrealistic expectations and 6-month, post-treatment outcomes. METHODS: We performed a retrospective analysis of a large cohort of patients with NeP (n = 789) attending tertiary care centres to determine the association between unrealistic (both positive and negative) and realistic expectations with outcomes after multidisciplinary treatment. An expectation variable with three categories was calculated: realistic expectations were those whose expected reduction in pain was similar to the observed mean group reduction in pain, while optimistic and pessimistic expectations were those who over- or under-estimated the expected response to treatment, respectively. The association between baseline realistic/unrealistic expectations and 6-month pain-related disability, catastrophizing and psychological distress was assessed. RESULTS: Univariable analyses suggested that realistic expectations were associated with lower levels of disability, catastrophizing and psychological distress, compared to unrealistic expectations. However, after adjustment for baseline symptom severity, multivariable analysis revealed that patients with optimistic expectations had lower levels of disability, than those with realistic expectations. Those with pessimistic expectations had higher levels of catastrophizing and psychological distress at follow-up. CONCLUSIONS: These findings are largely congruent with the self-fulfilment perspective to expectations. SIGNIFICANCE: This study defined realistic pain expectations with patient data. Examining the relationship between expectations between pain and disability in a large cohort of patients with neuropathic pain.

The CanPain SCI Clinical Practice Guidelines for Rehabilitation Management of Neuropathic Pain after Spinal Cord: introduction, methodology and recommendation overview.

STUDY DESIGN: Clinical practice guidelines. OBJECTIVES: The objective was to develop the first Canadian clinical practice guidelines for the management of neuropathic pain in people with spinal cord injury (SCI). SETTING: The guidelines are relevant for inpatient and outpatient SCI rehabilitation settings in Canada. METHODS: The guidelines were developed in accordance with the Appraisal of Guidelines for Research and Evaluation II tool. A Steering Committee and Working Group reviewed the relevant evidence on neuropathic pain management (encompassing screening and diagnosis, treatment and models of care) after SCI. The quality of evidence was scored using Grading of Recommendations Assessment, Development and Evaluation (GRADE). A consensus process was followed to achieve agreement on recommendations and clinical considerations. RESULTS: The Working Group developed 12 recommendations for screening and diagnosis, 12 recommendations for treatment and 5 recommendations for models of care. Important clinical considerations accompany each recommendation. CONCLUSIONS: The Working Group recommendations for the management of neuropathic pain after SCI should be used to inform practice.

The CanPain SCI Clinical Practice Guidelines for Rehabilitation Management of Neuropathic Pain after Spinal Cord: Recommendations for treatment.

STUDY DESIGN: Clinical practice guidelines. OBJECTIVES: To develop the first Canadian clinical practice guidelines for treatment of neuropathic pain in people with spinal cord injury (SCI). SETTING: The guidelines are relevant for inpatient and outpatient SCI rehabilitation settings in Canada. METHODS: The CanPainSCI Working Group reviewed the evidence for different treatment options and achieved consensus. The Working Group then developed clinical considerations for each recommendation. Recommendations for research are also included. RESULTS: Twelve recommendations were developed for the management of neuropathic pain after SCI. The recommendations address both pharmacologic and nonpharmacologic treatment modalities. CONCLUSIONS: An expert Working Group developed recommendations for the treatment of neuropathic pain after SCI that should be used to inform practice.

The CanPain SCI Clinical Practice Guideline for Rehabilitation Management of Neuropathic Pain after Spinal Cord: recommendations for model systems of care.

STUDY DESIGN: Clinical practice guidelines. OBJECTIVES: The project objectives were to develop the first Canadian recommendations on a model of care for the management of at- and below-level neuropathic pain in people with spinal cord injury (SCI). SETTING: The guidelines are relevant for inpatient and outpatient SCI rehabilitation settings in Canada. METHODS: On the basis of a review of the Accreditation Canada standards, the Steering Committee developed questions to guide the CanPainSCI Working Group when developing the recommendations. The Working Group agreed on recommendations through a consensus process. RESULTS: The Working Group developed five recommendations for the organization of neuropathic pain rehabilitation care in people with SCI. CONCLUSIONS: The Working Group recommendations for a model of care for at- and below-level neuropathic pain after SCI should be used to inform clinical practice.

The CanPain SCI Clinical Practice Guidelines for Rehabilitation Management of Neuropathic Pain after Spinal Cord: screening and diagnosis recommendations.

STUDY DESIGN: Clinical practice guidelines. OBJECTIVES: To develop the first Canadian clinical practice guidelines for screening and diagnosis of neuropathic pain in people with spinal cord injury (SCI). SETTING: The guidelines are relevant for inpatient and outpatient SCI rehabilitation settings in Canada. METHODS: The CanPainSCI Working Group reviewed evidence to address clinical questions regarding screening and diagnosis of neuropathic pain after SCI. A consensus process was followed to achieve agreement on recommendations and clinical considerations. RESULTS: Twelve recommendations, based on expert consensus, were developed for the screening and diagnosis of neuropathic pain after SCI. The recommendations address methods for assessment, documentation tools, team member accountability, frequency of screening and considerations for diagnostic investigation. Important clinical considerations accompany each recommendation. CONCLUSIONS: The expert Working Group developed recommendations for the screening and diagnosis of neuropathic pain after SCI that should be used to inform practice.

Impact on health-related quality of life and costs of managing chronic neuropathic pain in academic pain centres: Results from a one-year prospective observational Canadian study.

BACKGROUND: The management of chronic pain, including neuropathic pain (NeP), is a major public health issue. However, there is a paucity of data evaluating pain management strategies in real-life settings. OBJECTIVE: To inform policy makers about the economic value of managing chronic NeP in academic centres by conducting a subeconomic assessment of a Canadian multicentre cohort study aimed at determining the long-term outcomes of the management of chronic NeP in academic pain centres. Specific questions regarding the economic value of this type of program were answered by a subset of patients to provide further information to policy makers. METHODS: Baseline demographic information and several pain-related measurements were collected at baseline, three, six and 12 months in the main study. A resource use questionnaire aimed at determining NeP-related costs and the EuroQoL-5 Dimension were collected in the subset study from consenting patients. Statistical analyses were conducted to compare outcomes over time and according to responder status. RESULTS: A total of 298 patients were evaluated in the present economic evaluation. The mean (± SD) age of the participants was 53.7±14.0 years, and 56% were female. At intake, the mean duration of NeP was >5 years. Statistically significant improvements in all pain and health-related quality of life outcomes were observed between the baseline and one-year visits. Use decreased over time for many health care resources (eg, visits to the emergency room decreased by one-half), which resulted in overall cost savings. CONCLUSION: The results suggest that increased access to academic pain centres should be facilitated in Canada.

Neuropathic pain in a primary care electronic health record database.

BACKGROUND: Neuropathic pain (NP) is common in the adult population but is difficult to study in electronic health record (EHR) databases because it is a symptom rather than a pathologic diagnosis. The first step in studying NP in EHR databases is to develop methods for identifying patients with NP. The objectives of this study were to develop estimates of the prevalence of NP among patients in a primary care EHR database and describe these patients' demographic characteristics and health-care utilization. METHODS: This was a retrospective cohort study of de-identified data from a 5-year period (2005-2010) from 23 general practitioners (GPs) in 10 primary care practices in southwestern Ontario, Canada. International Classification of Diseases version 9 (ICD-9) diagnostic codes and medication prescriptions were used to identify patients with certain and probable NP. RESULTS: Different methods produced prevalence estimates ranging from 1.5% (for certain NP in the epidemiologically rigorous period cohort) to 11.2% (for certain NP + probable NP in the more inclusive database cohort). Patients in the NP groups had more GP visits, specialist referrals and analgesic prescriptions than patients without NP. CONCLUSION: This study represents a step towards being able to utilize EHR databases to study NP by proposing methods to identify patients with certain and probable NP in a primary care EHR database. Validation against a gold standard is the next step.

Establishing a multicentre clinical research network: lessons learned.

BACKGROUND: Within many health care disciplines, research networks have emerged to connect researchers who are physically separated, to facilitate sharing of expertise and resources, and to exchange valuable skills. A multicentre research network committed to studying difficult cancer pain problems was launched in 2004 as part of a Canadian initiative to increase palliative and end-of-life care research capacity. Funding was received for 5 years to support network activities. METHODS: Mid-way through the 5-year granting period, an external review panel provided a formal mid-grant evaluation. Concurrently, an internal evaluation of the network by survey of its members was conducted. Based on feedback from both evaluations and on a review of the literature, we identified several components believed to be relevant to the development of a successful clinical cancer research network. RESULTS: THESE COMMON ELEMENTS OF SUCCESSFUL CLINICAL CANCER RESEARCH NETWORKS WERE IDENTIFIED: shared vision, formal governance policies and terms of reference, infrastructure support, regular and effective communication, an accountability framework, a succession planning strategy to address membership change over time, multiple strategies to engage network members, regular review of goals and timelines, and a balance between structure and creativity. CONCLUSIONS: In establishing and conducting a multi-year, multicentre clinical cancer research network, network members were led to reflect on the factors that contributed most to the achievement of network goals. Several specific factors were identified that seemed to be highly relevant in promoting success. These observations are presented to foster further discussion on the successful design and operation of research networks.

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.

Methadone in the management of intractable neuropathic noncancer pain.

OBJECTIVE: To evaluate the role of methadone in the management of intractable neuropathic noncancer pain. METHODS: A case series of 50 consecutive noncancer pain patients who were seen at a tertiary care centre and treated with oral methadone for a variety of intractable neuropathic pain states. RESULTS: The mean age was 52.7 years and the mean duration of follow-up was 13.9 months. Post-discectomy nerve root fibrosis, complex regional pain syndrome, peripheral neuropathy and central spinal cord pain syndromes were the most common diagnoses. Over 90% had been treated with one or more tricyclic antidepressants and anticonvulsants and a similar number had received other adjuvant analgesics. All patients had failed treatment with one or more conventional opioid analgesics (mean 2.8) at a mean maximal morphine dose of 384 mg (or equivalents) per day. Twelve patients had failed spinal cord stimulation. Nineteen patients (38%) did not tolerate initial methadone titration or thought their pain was worse on methadone. Five patients (10%) declared initial benefit but required repetitive dose escalation and eventually became non-responders. Twenty-six patients (52%) reported mild (4), moderate (15), marked (6) or complete (1) pain relief and continued on methadone at a mean maintenance dose of 159.8 mg/day for a mean duration of 21.3 months. Fourteen patients (28%) reported improved function on methadone relative to previous treatments. CONCLUSIONS: Methadone appears to have unique properties including N-methyl-D-aspartate antagonist activity that may make it especially useful in the management of intractable neuropathic pain. This observation needs to be tested in randomized, controlled trials.

Treatment of neuropathic pain with venlafaxine.

OBJECTIVE: To report a case of successful treatment of neuropathic pain with venlafaxine. CASE REPORT: A 39-year-old white woman presented with neuropathic back pain. The patient obtained 50% pain relief with consecutive use of amitriptyline, desipramine, and imipramine. Anticholinergic effects prompted a switch to extended-release venlafaxine 75 mg/d. Pain relief was as effective with this therapy as with the tricyclic antidepressants. The absence of adverse effects allowed the patient to discontinue all laxatives. DISCUSSION: Venlafaxine is an antidepressant that inhibits reuptake of norepinephrine and serotonin. This is the major mechanism by which tricyclic antidepressants relieve neuropathic pain. Venlafaxine does not bind to muscarinic-cholinergic, histaminic or alpha1-adrenergic receptors responsible for the common adverse effects seen with tricyclic antidepressants. CONCLUSIONS: This report describes the efficacious use of venlafaxine in the treatment of neuropathic pain. Double-blind, randomized, controlled trials are needed to explore this further.

Systemic drug treatment for chronic musculoskeletal pain.

OBJECTIVE: The purpose of this review was to determine how effective different classes of analgesic agents are in the management of chronic pain. METHODOLOGY: The literature search identified five systematic reviews and 18 randomized controlled trials to provide evidence about systemic drug treatment for chronic pain. RESULTS: Studies in the systematic reviews were mainly of low back pain, and studies in the randomized controlled trials were mainly of fibromyalgia. Other studies investigated of rheumatic pain, musculoskeletal pain, chronic low back pain, and temporomandibular pain. Classes of analgesic agents reviewed were antidepressants, nonsteroidal anti-inflammatory drugs, muscle relaxants, opioid analgesics, and a number of miscellaneous agents. CONCLUSIONS: For chronic pain, opioid analgesics provide benefit for up to 9 weeks (level 2). For chronic low back pain, the evidence shows that various types of nonsteroidal antiinflammatory drugs are equally effective or ineffective, and that antidepressants provide no benefit in the short to intermediate term (level 2). Muscle relaxants showed limited effectiveness (level 3) for chronic neck pain and for chronic low back pain for up to 4 weeks. For fibromyalgia, there is limited evidence (level 3) of the effectiveness of amitryptiline, ondansetron, zoldipem, or growth hormone, and evidence of no effectiveness for nonsteroidal anti-inflammatory drugs, malic acid with magnesium, calcitonin injections, or s-adenyl-L-methionine. For temporomandibular pain, oral sumatriptan is not effective (level 2). The remaining evidence was inadequate (level 4a) or contradictory (level 4b).

Segmental hyperhidrosis as a manifestation of spinal and paraspinal disease.

BACKGROUND: Segmental hyperhidrosis is an uncommon finding which is usually associated with irritation or infiltration of pre-ganglionic sympathetic fibres or the sympathetic chain. METHODS: We report two cases of segmental hyperhidrosis with striking clinical features. RESULTS: In one case, a mesothelioma produced ipsilateral simultaneous underactivity and overactivity of sympathetic outflow and in the other case a thoracic central disc herniation was probably responsible for a band of sweating which clearly extended beyond the segmental level of injury. CONCLUSION: Segmental hyperhidrosis should trigger a search for structural disease in the spinal and paraspinal region.

Pain in central and peripheral demyelinating disorders.

Moderate to severe pain is a common feature of central and peripheral demyelinating disorders. Pain in multiple sclerosis tends to occur when the disease is well-established and usually lingers infinitely. Pain in Guillain-Barré syndrome tends to be particularly severe at the time of initial presentation and usually resolves over 8 to 12 weeks. Pain in both conditions is generally caused by either the direct effects of nerve injury or the result of paralysis and prolonged immobilization. Pain syndromes are well-defined in each disorder based on the underlying pathophysiology. Treatment involves a variety of pharmacologic and nonpharmacologic approaches individualized for each specific pain syndrome.

A clinical evaluation of transdermal therapeutic system fentanyl for the treatment of cancer pain.

Fentanyl has been incorporated into a transdermal therapeutic system (TTS) containing a rate-limiting membrane that provides constant release of the opioid. TTS fentanyl provides continuous opioid delivery for up to 72 hr without the need for special equipment. After Institutional Review Board approval, 53 patients with cancer pain requiring 45 mg or more of oral morphine daily were admitted into an open-label, prospective, multicenter evaluation of TTS fentanyl for the relief of pain. After a 1-week stabilization on oral morphine, patients were transferred from morphine to an appropriate dose of TTS-fentanyl (25, 50, 75, or 100 micrograms/hr) administered as a transdermal patch every 3 days. TTS fentanyl was titrated to pain relief, and patients were followed up for as long as 3 months. Pain relief and the side effects of the medications were assessed daily. Twenty-six men and 27 women with a mean (+/- SD) age of 61 (+/- 12) years entered the study; 23 patients completed the full 84-day study. The mean duration of TTS fentanyl use was 58 +/- 32 days. The mean (+/- SEM) daily morphine dose during the last 2 days of stabilization was 189 (+/- 20) mg, and the mean initial fentanyl patch dose was 58 (+/- 6) micrograms/hr. The mean daily morphine dose taken "as needed" for breakthrough pain at study completion was 35 mg. The mean final fentanyl dosage at study completion was 169 (+/- 29) micrograms/hr. Pain relief was rated as good or excellent by 82% of patients during the treatment period. When asked to compare pain relief during the first month of TTS-fentanyl use to that provided by their last analgesic before study entry, 63% preferred TTS fentanyl. Side effects considered related to the fentanyl patch were nausea (13%), vomiting (8%), skin rash (8%), and drowsiness (4%). Thirty percent of patients reported adverse experiences related to the fentanyl patch, and 17% had to be discontinued from the study. We conclude that TTS fentanyl administered every 3 days for the treatment of cancer pain is effective, safe, and well tolerated by most patients.

Pain in Guillain-Barré syndrome.

OBJECTIVES: To determine the character, intensity and frequency of pain in Guillain-Barré syndrome (GBS) and to evaluate the response to treatment. DESIGN: A prospective longitudinal study. SETTING: Academic hospital-based practices. PATIENTS: Fifty-five consecutive patients with GBS. INTERVENTIONS: Patients were evaluated on admission and at 2, 4, 8, 16, and 24 weeks. MAIN OUTCOME MEASURES: Character of pain, pain intensity using Visual Analogue Scale ([VAS] 0 to 10 cm) and Present Pain Intensity of McGill Pain Questionnaire, pain relief (VAS 0 to 10 cm), Disability Grading Scale for GBS. RESULTS: Forty-nine patients (89.1%) described pain during the course of their illness. On admission, mean pain intensity (VAS) was 4.7 +/- 3.3. However, 26 patients (47.3%) described pain that was either distressing, horrible, or excruciating (mean VAS, 7.0 +/- 2.0). The most common pain syndromes observed were deep aching back and leg pain and dysesthetic extremity pain. Pain intensity on admission correlated poorly with neurologic disability on admission (r = 0.26, p = 0.06) and throughout the period of study (r < 0.20, p > 0.10). Forty-one patients (74.5%) required opioid analgesics, with 16 (29.0%) receiving parenteral morphine to provide adequate pain relief. CONCLUSIONS: Moderate to severe pain is a common and early symptom of GBS and requires aggressive treatment. Pain intensity on admission is not a predictor of poor prognosis. Back and leg pain usually resolves over the first 8 weeks, but dysesthetic extremity pain may persist longer in 5 to 10% of patients despite motor recovery and the use of adjuvant analgesics.

Randomised trial of oral morphine for chronic non-cancer pain.

BACKGROUND: The use of opioid analgesics for chronic non-cancer pain is controversial. Some surveys report good pain relief and improvement in performance while others suggest a poor outcome with a propensity to psychological dependence or addiction. METHODS: We undertook a randomised double-blind crossover study to test the hypothesis that oral morphine relieves pain and improves the quality of life in patients with chronic regional pain of soft tissue or musculoskeletal origin who have not responded to codeine, anti-inflammatory agents, and antidepressants. Morphine was administered as a sustained-release preparation in doses up to 60 mg twice daily and compared with benztropine (active placebo) in doses up to 1 mg twice daily over three-week titration, six-week evaluation, and two-week washout phases. Pain intensity, pain relief, and drug liking were rated weekly and psychological features, functional status, and cognition were assessed at baseline and at the end of each evaluation phase. FINDINGS: After dose titration in the 46 patients who completed the study, the mean daily doses of drugs were morphine 83.5 mg and benztropine 1.7 mg. On visual analogue scales, the morphine group showed a reduction in pain intensity relative to placebo in period I (p = 0.01) and this group also fared better in a crossover analysis of the sum of pain intensity differences from baseline (p = 0.02). No other significant differences were detected. INTERPRETATION: In patients with treatment-resistant chronic regional pain of soft-tissue or musculoskeletal origin, nine weeks of oral morphine in doses up to 120 mg daily may confer analgesic benefit with a low risk of addiction but is unlikely to yield psychological or functional improvement.

The dose-response relationship of controlled-release codeine (Codeine Contin) in chronic cancer pain.

The improved pain control provided by regular dosing of opioid analgesics in patients with severe cancer pain has been well established. However, the treatment of mild-to-moderate cancer pain is often limited to "as needed" dosing with fixed combinations of codeine or oxycodone plus a nonopioid analgesic, which do not allow optimal titration of the individual components. This randomized double-blind study was designed to evaluate the efficacy of controlled-release codeine (Codeine Contin) in patients with cancer pain, and to estimate its dose equivalence to a standard combination of acetaminophen plus codeine. Twenty-four patients with at least moderate cancer pain were randomized to Codeine Contin 100, 200, or 300 mg every 12 hr or acetaminophen plus codeine (600 mg/60 mg) every 6 hr. On days 1 and 4 of dosing, pain intensity and pain relief were assessed hourly for 12 hr. The sum of pain intensity differences (SPID) from baseline and the total pain relief (TOTPAR) scores demonstrated a dose-response relationship for Codeine Contin on days 1 and 4 that was statistically significant on day 1 and suggested greater analgesic efficacy on day 4, compared with day 1. Codeine Contin 150 mg every 12 hr was estimated to be equianalgesic to acetaminophen plus codeine (600 mg/60 mg) given every 6 hr. Because a similar equivalence was also demonstrated from analysis of adverse event data, it is concluded that Codeine Contin 150 mg produces analgesia and a side-effect profile similar to a 40% lower dose of codeine provided by the combination.(ABSTRACT TRUNCATED AT 250 WORDS)