Jon H. Raphael

A systematic literature review of psychological characteristics as determinants of outcome for spinal cord stimulation therapy

&NA; Psychological factors are deemed important when considering patients for suitability for Spinal Cord Stimulation (SCS). However, there is to date no consensus on which psychological characteristics or tests to undertake. This review analyses the literature to determine findings concerning the psychological characteristics observed and their impact on SCS efficacy for chronic pain. A search in the databases Cochrane, EBSCOhost (CINAHL, MEDLINE, PsycINFO and PsycARTICLES) and a hand search of reference lists from selected articles were performed, resulting in nine relevant articles. The Minnesota Multiphasic Personality Inventory was the most commonly used tool for assessing psychological factors. Only one study used a semi‐structured interview instead of questionnaires. Studies lacked long term followup. Depression was identified in six studies as a factor that reduces efficacy, also as a characteristic that can improve after successful SCS by two studies. One study did not include patients with depression, due to previous research indicating depression as a contra‐indication. Hypochondriasis and hysteria had conflicting results for prediction of efficacy. Mania was predicted by only two studies as a positive indicator for success. Further long term studies of psychological factors on outcome from SCS are needed.

Neuropathic pain in osteoarthritis: A review of pathophysiological mechanisms and implications for treatment

OBJECTIVES Osteoarthritis (OA) is the leading cause of musculoskeletal pain and functional disability worldwide, affecting a growing number of individuals in the western society. Despite various conservative and interventional treatment approaches, the overall management of the condition is problematic, and pain-the major clinical problem of the disease-remains sub-optimally controlled. The objectives of this review are to present the pathophysiologic mechanisms underlying the complexity of pain in OA and to discuss the challenges for new treatment strategies aiming to translate experimental findings into daily clinical practice. METHODS A narrative literature review of studies investigating the existence of a neuropathic component in OA pain was conducted. We searched PubMed, Embase and Scopus for English language publications. A hand-search of reference lists of relevant studies was also performed. RESULTS Recent advances have shed additional light on the pathophysiology of osteoarthritic pain, highlighting the contribution of central pain pathways together with the sensitisation of peripheral joint receptors and changes of the nociceptive process induced by local joint inflammation and structural bone tissue changes. Thus, a neuropathic pain component may be predominant in individuals with minor joint changes but with high levels of pain refractory to analgesic treatment, providing an alternative explanation for osteoarthritic pain perception. CONCLUSION A growing amount of evidence suggests that the pain in OA has a neuropathic component in some patients. The deeper understanding of multiple mechanisms of OA pain has led to the use of centrally acting medicines that may have a benefit on alleviating osteoarthritic pain. The ineffective pain management and the increasing rates of disability associated with OA mandate for change in our treatment paradigm.

A Narrative Review of the Impact of Disbelief in Chronic Pain

Although the experience of being believed is frequently alluded to in chronic pain literature, few studies have specifically explored this phenomenon and even fewer reviews have been offered. This narrative review sought to explore the wider social context in which individuals with chronic pain may experience disbelief toward their pain. Articles were obtained through a search of eight databases and a hand search of the references of full-text papers. Key results within the articles were noted and integrated to form three main themes: stigma, the experience of isolation, and the experience of emotional distress. The experience of stigma can occur in a number of ways. It may be through actual or perceived encounters with others; it can be through the use of psychologic explanations of pain; it can come through a perceived challenge to ones integrity and subsequently affect an individuals identity; and such stigma may be influenced by negative female stereotypes. The loss of relationships associated with being disbelieved can lead to the experience of isolation. This may be self-initiated, particularly when an individual has been given a contested diagnosis. Finally, disbelief can lead to emotional distress. This can take the form of guilt, depression, and anger. Throughout the article, implications for health care professionals, working with individuals living with chronic pain, are discussed.

The Cost-Effectiveness of Spinal Cord Stimulation for Complex Regional Pain Syndrome

OBJECTIVES Health-care policymakers and payers require cost-effectiveness evidence to inform their treatment funding decisions. The aims of this study were to assess the cost-effectiveness of the addition of spinal cord stimulation (SCS) compared with conventional management alone (CMM) in patients with complex regional pain syndrome (CRPS), and to determine the cost-effectiveness of nonrechargeable versus rechargeable SCS implanted pulse generators (IPGs). METHODS A decision analytic model was used to synthesize data on CRPS patient outcomes and health-care costs over a 15-year time horizon from the perspective of the UK National Health Services. Data were sourced from two SCS randomized controlled trials. Results are expressed as an incremental cost per quality-adjusted life-year (QALY) in 2008 GBP. RESULTS The incremental cost-effectiveness of SCS compared with CMM was £3562 per QALY, a finding that was robust across sensitivity analyses with an 87% probability that SCS is cost-effective at a willingness to pay threshold of £30,000. When the longevity of an IPG is 4 years or less, a rechargeable (and initially more expensive) IPG is more cost-effective than a nonrechargeable IPG. CONCLUSIONS In selected patients with CRPS, SCS is cost-effective as an adjunct to CMM. Despite their initial increased expense, rechargeable IPGs should be considered when IPG longevity is likely to be short. These findings support policymakers to extend the use of SCS as a good value for money treatment for CRPS.

No room for reflexivity? Critical reflections following a systematic review of qualitative research

We conducted a systematic search of qualitative research into the individual’s experience of chronic low back pain. Two reviewers independently read through 740 unique abstracts. Inter-rater reliability was fair. The final sample comprised 19 articles which we critiqued using the Critical Appraisal Skills Programme checklist. This article focuses on the critical appraisal. Limitations include a lack of an adequate rationale for the theoretical framework, a lack of an account for the decisions made across recruitment and data collection, and a lack of reflexivity. Finally we discuss and offer recommendations for reflexivity and the explication of qualitative methodology in research articles.

Intrathecal inflammatory masses: is the yearly opioid dose increase an early indicator?

Objectives:  The objective of this study is to investigate the association between intrathecal drug, flow rate, drug concentration, and drug dose with the formation of intrathecal inflammatory masses.

Long-term intrathecal drug administration for chronic nonmalignant pain.

Background: Chronic pain of nonmalignant origin requires effective long-term treatments, as for many patients pain management will be necessary throughout the rest of their lives. Intrathecal drug delivery systems (IDDS) have become a recognized therapy for the management of severe and otherwise intractable chronic pain. However, it is still not clear whether this treatment can be effective for periods up to 10 years or longer, given the paucity of long-term follow-up. This study sought to examine the effectiveness of IDDS following an average of 13 years postimplantation. Methods: Twenty patients participated in a longitudinal study with an average follow-up of 13.5 years (range: 10.4 to 17.9) after IDDS implantation. Investigation was carried out by means of a questionnaire before IDDS and after an average of 4 and 13 years of IDDS therapy. Assessment of pharmacological data and complications/side effects was performed. Results: Statistically significant improvements between baseline and 4-year assessment were observed for the following sensory and psychosocial variables: pain intensity, pain relief, coping, self-efficacy, depression, quality of life, housework, mobility, sleep, and social life (all P<0.001). No statistically significant changes were detected between assessments at averages of 4 and 13.5 years. Conclusions: This study, with one of the longest follow-up intervals reported in the IDDS literature, shows that IDDS has the potential to be a life-long pain management solution in appropriately selected patients with chronic nonmalignant pain.

Hypogonadism and low bone mineral density in patients on long-term intrathecal opioid delivery therapy

Objectives This study aimed to investigate the hypothalamic-pituitary-gonadal axis in a sample of male patients undertaking intrathecal opioid delivery for the management of chronic non-malignant pain and the presence of osteopaenia and/or osteoporosis in those diagnosed with hypogonadism. Design Observational study using health data routinely collected for non-research purposes. Setting Department of Pain Management, Russells Hall Hospital, Dudley, UK. Patients Twenty consecutive male patients attending follow-up clinics for intrathecal opioid therapy had the gonadal axis evaluated by measuring their serum luteinising hormone, follicle stimulating hormone, total testosterone, sex hormone binding globulin and calculating the free testosterone level. Bone mineral density was measured by DEXA scanning in those patients diagnosed with hypogonadism. Results Based on the calculated free testosterone concentrations, 17 (85%) patients had biochemical hypogonadism with 15 patients (75%) having free testosterone <180 pmol/L and 2 patients (10%) between 180 and 250 pmol/L. Bone mineral density was assessed in 14 of the 17 patients after the exclusion of 3 patients. Osteoporosis (defined as a T score ≤−2.5 SD) was detected in three patients (21.4%) and osteopaenia (defined as a T score between −1.0 and −2.5 SD) was observed in seven patients (50%). Five of the 14 patients (35.7%) were at or above the intervention threshold for hip fracture. Conclusions This study suggests an association between hypogonadism and low bone mass density in patients undertaking intrathecal opioid delivery for the management of chronic non-malignant pain. Surveillance of hypogonadism and the bone mineral density levels followed by appropriate treatment may be of paramount importance to reduce the risk of osteoporosis development and prevention of fractures in this group of patients.

Type of Interventional Pain Procedure, Body Weight, and Presence of Spinal Pathology are Determinants of the Level of Radiation Exposure for Fluoroscopically Guided Pain Procedures

Abstract:  In the recent years new technology has led to the development of a bewildering array of imaging procedures. Yet, conventional radiography remains one of the most used tools to diagnose and to aid procedural interventions. Fluoroscopy guidance facilitates targeted drug delivery or radiofrequency directly to the area of pathology, a benefit that has to be balanced against the risks of radiation exposure. In this prospective observational survey of routine practice, dose area product (DAP) and screening time (ST) were recorded in 127 consecutive patients undergoing fluoroscopically guided spinal procedures along with other probable measures of potentially greater radiation exposure such as weight, type of spinal pathology, the ease of recognition of the anatomical landmarks, and the radiographic quality of the image in terms of contrast and graininess. The mean ST was 34 ± 27 seconds (range, 3 to 218 seconds), the mean DAP was 1.18 ± 1.08 Gy cm2 (range, 0.023 to 6.82 seconds). A correlation between weight and DAP was confirmed (r = 0.230, P < 0.05, Spearman’s correlation coefficient). Patients with spinal pathology (n = 33) had higher radiation exposure than those without (DAP median = 0.85, U = 978.00, P < 0.005, r = −0.28, Mann–Whitney test). The DAP values obtained compare favourably with the recommended doses for radiographs and other procedures, although they generally exceed the values for a chest X‐ray. ▪

Randomized Double-Blind Sham-Controlled Crossover Study of Short-Term Effect of Percutaneous Electrical Nerve Stimulation in Neuropathic Pain

BACKGROUND Percutaneous electrical nerve stimulation (PENS) is an electrical neuromodulation technique that has shown its therapeutic potential in various chronic pain conditions over the past few years, but well-blinded controlled studies are lacking. PATIENTS AND METHODS A randomized double-blind sham-controlled crossover trial on 31 patients with chronic pain with surface hyperalgesia to investigate the efficacy of PENS. RESULTS For the active PENS therapies, the median numerical rating scale (NRS) for pain changed from 7.5 (standard deviation [SD] ± 1) (range 6-10) before therapy to 0.5 (range 0-8.5) after therapy (Z = -4.206, P < 0.0005 [two-tailed]). The mean pain pressure threshold (PPT) measured with the von Frey aesthesiometer changed from 202 gm (SD ± 137 gm) (range 55-800 gm) before therapy to 626 gm (SD ± 228 gm) (range 45-800 gm) after therapy (Z = -4.373, P < 0.0005 [two-tailed]). There was a statistically significant difference between the changes in NRS for the active (3.9 [±3.2][0-8]) compared with the sham (0.1 [±0.4][0-1.5]) therapies, U = 40, Z = -3.484, P < 0.0001 (two-tailed). There was a statistically significant difference between the changes in PPT for the active (310 gm [±267 gm][0-670 gm]) compared with the sham (8 gm [±4 gm][0-15 gm]) therapies, U = 48.5, Z = -2.699, P = 0.007 (two-tailed). CONCLUSION PENS therapy appears to be effective in providing short-term pain relief in chronic pain conditions. Studies, involving larger sample sizes and longer follow-up are recommended.