European Journal of Pain

Some chronic painful conditions including e.g. fibromyalgia, whiplash associated disorders, endometriosis, and irritable bowel syndrome are associated with generalized musculoskeletal hyperalgesia. The aim of the present study was to determine whether generalized deep‐tissue hyperalgesia could be demonstrated in a group of patients with chronic low‐back pain with intervertebral disc herniation. Twelve patients with MRI confirmed lumbar intervertebral disc herniation and 12 age and sex matched controls were included. Subjects were exposed to quantitative nociceptive stimuli to the infraspinatus and anterior tibialis muscles. Mechanical pressure (thresholds and supra‐threshold) and injection of hypertonic saline (pain intensity, duration, distribution) were used. Pain intensity to experimental stimuli was assessed on a visual analogue scale (VAS). Patients demonstrated significantly higher pain intensity (VAS), duration, and larger areas of pain referral following saline injection in both infraspinatus and tibialis anterior. The patients rated significantly higher pain intensity to supra‐threshold mechanical pressure stimulation in both muscles. In patients, the pressure pain‐threshold was lower in the anterior tibialis muscle compared to controls. In conclusion, generalized deep‐tissue hyperalgesia was demonstrated in chronic low‐back pain patients with radiating pain and MRI confirmed intervertebral disc herniation, suggesting that this central sensitization should also be addressed in the pain management regimes.

Background: Chronic, unexplained pain is a common, ill‐understood clinical problem. Increased sensitivity for pain and other stimuli is often implied as an underlying mechanism. Attentional processes influence central pain processing and might mediate hypersensitivity at a cerebral level.

Aims: To study patients with chronic, unexplained pain with respect to (a) subjective pain experience; (b) effects of attentional manipulation; (c) level at which alterations in pain processing occur: locally (symptomatic body region), or generalised.

Methods: We compared 16 patients with chronic, unexplained limb pain with 16 matched healthy controls. Pain thresholds to electrical stimuli were recorded. Subjects then received individually thresholded painful and non‐painful stimuli, with manipulation of attention towards or away from pain. The intensity of pain perception was recorded by means of visual analogue scales (VAS). Pain thresholds and effects of Attention and Laterality on VAS scores were compared between groups by means of general linear modelling (restricted to 12 patients with unilateral pain and 12 controls).

Results: Distraction increased thresholds for pain in healthy volunteers, but this effect was significantly attenuated in patients. Significant interactions between attention‐effects, stimulus laterality and stimulus intensity indicated that VAS scores for painful stimuli were attenuated during distraction in healthy controls, but not in pain patients.

Conclusions: Results support the notion that pain processing is enhanced in chronic, unexplained pain, and that the influence of attentional modulation on pain processing is attenuated. Potential cerebral mechanisms are changes in either attentional allocation or attention‐mediated descending pain modulation. The changes seem to occur at a generalised level.

Neuropathic pain is caused by injury of the peripheral or central nervous system. The neurological examination of the sensory system in neuropathic pain patients guides the anatomical localization of the injury. Among the sensory modalities to be tested, priority should be given to those subserved by small peripheral sensory fibers or by the spinothalamic tract that most commonly are abnormal in neuropathic pain patients. Testing of cold and warm perception was traditionally carried out in the clinic using tubes filled with water at different temperatures, a cumbersome method that has limited the routine examination of these sensory modalities. The Lindblom roller offers a practical and effective method of readily testing temperature perception and is among the best available clinical tools for delineating the anatomical boundaries of a sensory abnormality. Routinely use of the Lindblom roller shall be standard bedside clinical assessment of neuropathic pain patients. To exemplify this statement we describe two patients affected by complex and fluctuating painful sensory abnormalities caused by an extradural mass compressing the spinal cord. The level of the injury was readily localized with a roller kept at room temperature.

Pain self‐efficacy and fear of movement have been proposed to explain how pain can lead to disability for patients with chronic low back pain. However the extent to which pain self‐efficacy and fear of movement mediate the relationship between pain and disability over time has not been investigated. This study aimed to investigate whether pain self‐efficacy and/or fear of movement mediate the relationship between pain intensity and disability in patients with recent onset chronic low back pain. In a two‐wave longitudinal design, 184 chronic low back pain patients completed measures for pain intensity, disability, pain self‐efficacy and fear of movement at baseline and 12 months after the onset of chronic low back pain. Regression analyses were used to test the mediational hypothesis. We found that, when measured at the same time, both pain self‐efficacy and fear of movement beliefs partially mediated the effects of pain intensity on disability at the onset of chronic low back pain. However, in the longitudinal analyses, only improvements in self‐efficacy beliefs partially mediated the relationship between changes in pain and changes in disability over a 12 months period. We found no support for the theory that fear of movement beliefs mediate this relationship. Therefore, we concluded that pain self‐efficacy may be a more important variable than fear of movement beliefs in terms of understanding the relationship between pain and disability.

Research indicates that anxiety sensitivity may be related to the negative experience of pain, especially amongst women. Further evidence with chronic pain patients indicates that anxiety sensitivity may result in avoidance pain‐coping strategies. However, this effect has not yet been experimentally investigated in healthy groups. Therefore, the current study sought to investigate the effect of anxiety sensitivity and coping on women’s responses to pain. Thirty women who were classified as high in anxiety sensitivity and 30 women classified as low in anxiety sensitivity participated. Within each anxiety sensitivity group, half the participants (n = 15) were randomly instructed to either focus on or avoid cold pressor pain sensations. As expected, women high in anxiety sensitivity were found to report higher levels of sensory and affective pain. Also, and consistent with previous research into anxiety sensitivity, no differences were found between anxiety sensitivity groups for measures of pain threshold or pain tolerance. The pain coping instruction manipulation was found to moderate pain experience, in that the avoidance strategy resulted in higher pain ratings compared to when instructed to focus. Finally, high anxiety sensitive women reported greater pain when instructed to avoid rather than focus on cold pressor pain. These results are discussed in light of previous research and future directions for pain management.

Chronic non‐cancer pain is a complex biopsychosocial phenomenon; as such it is unlikely that any one treatment modality will achieve relief. There is increasing availability of oral opioid preparations and an associated increased level of prescribing; consequently in 1997 the Australian Pain Society drew up some management strategies for their use. This paper reviews the principles of those strategies, stressing that oral opioids should not be used in isolation nor used to treat ‘distress’ often associated with chronic pain. The place of a trial of opioid and informed consent are discussed.

Research on widespread pain often relies upon case definitions bounded by duration limits or “cut‐offs.” In clinical reality, however, there are no natural cut‐off points between localized and widespread pain. Rather, pain is best represented by a continuum of “widespreadness” from localized pain to pain spread across the body. The objective of this paper was to describe the number of pain sites (NPS) reported in a population study and its association with demographic, lifestyle, and health‐related factors. Using a cross‐sectional design, the Standardized Nordic Questionnaire was used to measure musculoskeletal pain among seven age groups in Ullensaker, Norway (n=2926). Results showed that women reported a higher mean NPS than men. A higher NPS was also found for individuals who were separated or divorced, undergoing rehabilitation, or who had a disability pension. Additionally, greater NPS was reported by smokers, individuals with less physical activity, and a higher BMI. A strong linear relationship was found between NPS and reduction in overall health, sleep quality, and psychological health. Results from a multivariate linear regression analysis showed that overall health, sleep quality, and gender demonstrated the strongest associations with increasing NPS, accounting for 31.4% of the variance. Our study indicates that the straightforward and simple method of counting the NPS could be important in managing the complex problem of musculoskeletal pain.

This study aimed to determine whether self‐efficacy beliefs mediated the relation between pain‐related fear and pain, and between pain‐related fear and disability in CLBP patients who exhibited high pain‐related fear. In a cross‐sectional design, 102 chronic low back pain (CLBP) patients completed measures for pain, disability, self‐efficacy and pain‐related fear (fear of movement and catastrophizing). Multistep regression analyses were performed to determine whether self‐efficacy mediated the relation between pain‐related fear and outcome (pain and/or disability). Self‐efficacy was found to mediate the relation between pain‐related fear and pain intensity, and between pain‐related fear and disability. Therefore, this study suggests that when self‐efficacy is high, elevated pain‐related fear might not lead to greater pain and disability. However, in instances where self‐efficacy is low, elevated pain‐related fear is likely to lead to greater pain and disability. In view of these findings, we conclude that it is imperative to assess both pain‐related fear and self‐efficacy when treating CLBP patients with high pain‐related fear.

Spinal cord stimulation is a minimally invasive mode of treatment in the management of certain forms of chronic pain that do not respond to conventional pain therapy. Several authors have reported encouraging findings with this technique. Over a 10‐year period in a single centre, 254 patients were subjected to a trial period of spinal cord stimulation with an externalized pulse generator. Two hundred and seventeen of the patients showed satisfactory results justifying permanent implantation of a spinal cord stimulation system. In 1998, an independent physician invited 153 patients (155 pain cases), who still had the system in place and who could be contacted, for an interview. The aim of this study was to evaluate the efficacy of an implanted spinal cord stimulation system in terms of pain relief and quality of life and to assess the accuracy of the patient selection criteria. The results of this study demonstrate a high success rate as evaluated by the patients' own assessments—68% of the patients rated the result of the treatment as excellent to good after an average follow‐up of almost 4 years. The resumption of work by 31% of patients who had been working before the onset of pain supports these positive findings.

The extent of surgical trauma was related to postoperative pain intensity in a previous study. However, more extensive surgical procedures with higher baseline pain intensity did not appear to influence the ability to document the additive analgesic effect of codeine when given with paracetamol, partly due to large interindividual variation in baseline pain intensity. The aim of the present study was to attempt to improve upside assay sensitivity in this dental pain model by: (1) selecting patients with high baseline pain intensity; and (2) closer supervision of outpatients' drug intake and compliance with protocol. Only patients with baseline pain ≥ 50 on a 100 mm visual analogue scale after wisdom tooth surgery were included. Twenty patients were given paracetamol 1000 mg with or without codeine 60 mg in repeated doses in a randomized and double‐blind manner. Intake of the first dose of test medication and its effects were closely supervised, while the two following doses were taken at 3‐h intervals after the patient had left the clinic. Pain intensity was measured with the visual analogue scale for 8 h. More pain relief was revealed when codeine 60 mg was added to paracetamol 1000 mg on the following measures of effect: change of pain intensity with time (p<0.05, MannWhitney), sum of pain intensities (p=0.019), pain intensity difference (p≤0.05), sum of pain intensity differences (p<0.05), pain reduction index (p<0.05) and global‐evaluation score (p=0.006).

The study confirms that this dental pain model, when controlled for sufficient and homogeneous baseline pain and patient compliance, does have sufficient upside assay sensitivity to discriminate between paracetamol with and without codeine.