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PubMed1991

A controlled trial of corticosteroid injections into facet joints for chronic low back pain.

BACKGROUND: Chronic low back pain is a common problem with many treatments, few of which have been rigorously evaluated. This randomized, placebo-controlled trial was designed to evaluate the efficacy of injections of corticosteroid into facet joints to treat chronic low back pain. METHODS: Patients with chronic low back pain who reported immediate relief of their pain after injections of local anesthetic into the facet joints between the fourth and fifth lumbar vertebrae and the fifth lumbar and first sacral vertebrae were randomly assigned to receive under fluoroscopic guidance injections of either methylprednisolone acetate (20 mg; n = 49) or isotonic saline (n = 48) in the same facet joints. Ninety-five patients were followed for six months and their condition assessed with scales of pain severity, back mobility, and limitation of function. RESULTS: After one month, none of the outcome measures evaluating pain, functional status, and back flexion differed clinically or statistically between the two study groups. Forty-two percent of the patients who received methylprednisolone and 33 percent of those who received placebo reported marked or very marked improvement (95 percent confidence interval for the difference, -11 to 28 percentage points; P = 0.53). The results were similar after three months. At the six-month evaluation, the patients treated with methylprednisolone reported more improvement, less pain on the visual-analogue scale, and less physical disability. The differences were reduced, however, when concurrent interventions were taken into account. Moreover, only 11 patients (22 percent) in the methylprednisolone group and 5 (10 percent) in the placebo group had sustained improvement from the first month to the sixth month (95 percent confidence interval for the difference, -2 to 26; P = 0.19). CONCLUSIONS: We conclude that injecting methylprednisolone acetate into the facet joints is of little value in the treatment of patients with chronic low back pain.

Adrenal Cortex Hormones↗
PubMed1984

Medication usage, emotional disturbance, and pain behavior in chronic low back pain patients.

Examined chronic low back pain outpatients (N = 126) at a university hospital outpatient back clinic. Prior to their orthopedic examination, patients were given the MMPI, the Pain Experience Questionnaire (a modified form of the McGill Pain Questionnaire), and a medical history form that indicated onset of injury, number of surgeries, functional limitations, and use of medications. Four patterns of drug usage emerged with sufficient number to permit statistical analysis: (1) none; (2) aspirin-type medications; (3) single narcotics alone; and (4) narcotics combined with other medications. Group 4 patients scored significantly higher on the Hypochondriasis and Hysteria scales than the others, whereas Group 3 patients scored higher on the PD (acting out) scale. Group 4 patients reported more intense pain and chose more affective terms (punishing/terrorizing/sickening) in describing their pain than the other three groups. Group 1 patients reported significantly less limitation in walking, running, and climbing.

Adult↗
PubMed1996

A practical approach to the patient with back pain.

Management of back pain is most likely to be effective when treatment is based on a specific diagnosis, when patients are followed proactively to recovery and when psychosocial factors receive appropriate attention. Selected non-habit-forming drugs are useful, especially when taken on a regular basis rather than on an "as needed" basis. Rest is less useful in the management of back pain than previously believed and may be counterproductive. Surgery has value only in carefully selected patients, primarily those with well-documented sciatic nerve injury that has not responded to a course of conservative treatment.

Acute Disease↗
PubMed2002

[Does sitting at work cause low back pain?].

INTRODUCTION: Low back pain (LBP) is a common condition that, according to standard textbooks and several review articles, is associated with sitting-while-at-work. However, to our knowledge, no meta-analysis or critical systematic literature reviews have been published. MATERIALS AND METHODS: The Medline, Embase, and OSH-ROM databases were searched for articles dealing with sitting at work in relation to low back pain for the years 1985-1997. Original studies were divided into those dealing with sitting-while-working and those dealing with sedentary occupations. Each article was systematically abstracted for core items. The quality of each article was determined on the representativeness of the study sample, response rate, the definition of LBP, and the statistical analysis. RESULTS: Thirty-five reports were identified: 14 dealing with sitting-while-working and 21 with sedentary occupations. Eight studies were found to fulfill the above-mentioned criteria. Regardless of quality, all but one of the studies failed to find a positive association between sitting-while-working and LBP. High quality studies showed a marginally negative association for sitting compared to diverse workplace exposures, for instance standing, driving, lifting, bending, and compared to diverse occupations. One low quality study associated sitting in a poor posture with LBP. DISCUSSION: Out of 35 studies, only eight fulfilled the very basic quality criteria. Nevertheless, both high-quality and low-quality studies are consistently in agreement about the lack of positive association, and we conclude that the extensive recent epidemiological literature does not support the popular opinion that sitting-while-at-work is associated with LBP.

Global Health↗
PubMed1999

The effect of stimulus frequency on the analgesic response to percutaneous electrical nerve stimulation in patients with chronic low back pain.

UNLABELLED: Low back pain (LBP) is one of the most common medical problems in our society. Increasingly, patients are turning to nonpharmacologic analgesic therapies such as percutaneous electrical nerve stimulation (PENS). We designed this sham-controlled study to compare the effect of three different frequencies of electrical stimulation on the analgesic response to PENS therapy. Sixty-eight consenting patients with LBP secondary to degenerative lumbar disc disease were treated with PENS therapy at 4 Hz, alternating 15 Hz and 30 Hz (15/30 Hz), and 100 Hz, as well as sham-PENS (0 Hz), according to a randomized, cross-over study design. Each treatment was administered for a period of 30 min three times per week for 2 wk. The pre- and posttreatment assessments included the health status survey short form and visual analog scales for pain, physical activity, and quality of sleep. After receiving all four treatments, patients completed a global assessment questionnaire. The sham-PENS treatments failed to produce changes in the degree of pain, physical activity, sleep quality, or daily intake of oral analgesic medications. In contrast, 4-Hz, 15/30-Hz, and 100-Hz stimulation all produced significant decreases in the severity of pain, increases in physical activity, improvements in the quality of sleep, and decreases in oral analgesic requirements (P < 0.01). Of the three frequencies, 15/30 Hz was the most effective in decreasing pain, increasing physical activity, and improving the quality of sleep (P < 0.05). In the global assessment, 40% of the patients reported that 15/30 Hz was the most desirable therapy, and it was also more effective in improving the patient's sense of well-being. We conclude that the frequency of electrical stimulation is an important determinant of the analgesic response to PENS therapy. Alternating stimulation at 15-Hz and 30-Hz frequencies was more effective than either 4 Hz or 100 Hz in improving outcome measures in patients with LBP. IMPLICATIONS: The frequency of electrical stimulation seems to be an important determinant of the analgesic efficacy of percutaneous electrical nerve stimulation. Mixed low- and high-frequency stimulation was more effective than either low or high frequencies alone in the treatment of patients with low back pain.

Analgesia↗
PubMed2002

Attributions, stress, and work-related low back pain.

Occupational low back pain (LBP) is a major cause of morbidity and cost. Efforts to control LBP are largely unsuccessful, and better understanding of risks is needed, especially psychological factors. The purpose of this research was to assess the association between worker attributions and LBP. Attributing LBP to internal causes may increase the worker's perceived control, whereas external attribution may cause distress. A new model was developed to explore these associations. A cross-sectional design was used in this study of 278 garment workers. Data were gathered by a self-administered questionnaire and through direct observation. Responses to questions on worker attributions of LBP cause and knowledge of back safety were subjected to factor analysis and other psychometric evaluation to develop scales. Six hypotheses were tested using multivariate logistic regression. Workers who scored high in internal attribution were more likely to be knowledgeable of back safety (OR = 3.7, 95% CI = 2.0-6.7). Workers reporting high demand were more likely to report LBP (OR = 2.3, 95% CI = 1.2-4.4). Workers attributing LBP to job tasks were more likely to report LBP (OR = 3.2, 95% CI = 1.5-6.9), and those reporting high supervisor support were less likely to report LBP (OR = 0.23, 95% CI = 0.08-0.66). Workers with annual incomes above 15,000 dollars were more likely to report LBP in the test of both the Demand-Control-Support and Attribution models (OR = 2.8, 95% CI = 1.2-6.9 and OR = 4.1, 95% CI = 1.5-11.1, respectively). While both models appeared to be useful for the study of low back pain, the R(2)(L) of the Demand-Control-Support model equaled only 11.9 percent, whereas the Attribution model equaled 26.2 percent. This study provides evidence that attribution theory is useful in the study of LBP, including in future interventions in the prevention of LBP.

Adult↗
PubMed1991

Pain and impairment beliefs in chronic low back pain: validation of the Pain and Impairment Relationship Scale (PAIRS).

Few validated instruments are available to assess beliefs and attitudes that patients have regarding pain, or ability to function despite discomfort. The Pain and Impairment Relationship Scale (PAIRS) was developed to tap these important beliefs and attitudes in chronic pain patients. Preliminary data indicate that the PAIRS is internally consistent and significantly related to impairment in a highly selected pain clinic sample of patients, including some chronic low back pain patients. The present study was designed to extend the validation of the PAIRS to a more general sample of chronic benign low back pain patients. Furthermore, additional tests supported the discriminant, convergent and divergent validity, as well as the reliability and relative independence from favorable self-report response bias of the PAIRS, by respectively demonstrating that: (1) the impairment beliefs assessed with the PAIRS were more prominent in chronic low back pain (CLBP) patients than in matched non-pain, healthy controls; (2) scores on the PAIRS were significantly related to measures of physical impairment, but not to physicians ratings of disease severity; (3) the impairment beliefs assessed with the PAIRS are readily distinguishable from cognitive distortions and emotional distress; (4) PAIRS scores for chronic low back pain patients are relatively consistent over time; and (5) PAIRS scores are not significantly associated with measures of favorable self-report response bias. We conclude that the PAIRS has demonstrated at least preliminary utility for applications by researchers and clinicians interested in chronic pain.

Adult↗
PubMed1991

Pain intensity measurement in chronic low back pain.

This study investigated the psychometric properties of eight pain intensity measures used with chronic low back pain patients. All measures were similar in terms of scale distribution and rates of incorrect responses, with all scales apart from the Pain Rating Index significantly correlated. Principal axis factoring of data from 92 patients indicated the presence of one general factor on which all pain intensity measures except the Pain Rating Index loaded. The 101-point Numeric Rating Scale and the Box Scale had the strongest relationship, with loadings of 0.90. The Numeric Rating Scale and the Box Scale appear to be the scales of choice for the measurement of pain intensity in the low back pain patient.

Adult↗
PubMed2001

Transcutaneous electrical nerve stimulation (TENS) for chronic low back pain.

BACKGROUND: Low back pain (LBP) affects a large proportion of the population. Transcutaneous electrical nerve stimulation (TENS) was introduced more than 30 years ago as an alternative therapy to pharmacological treatments for chronic pain. However, despite its widespread use, the effectiveness of TENS is still controversial. OBJECTIVES: The aim of this systematic review was to determine the efficacy of TENS in the treatment of chronic LBP. SEARCH STRATEGY: We searched MEDLINE, EMBASE, PEDro and the Cochrane Controlled Trials Register up to June 1, 2000. SELECTION CRITERIA: Only randomized controlled clinical trials of TENS for the treatment of patients with a clinical diagnosis of chronic LBP were included. Abstracts were excluded unless further data could be obtained from the authors. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials and extracted data using predetermined forms. Heterogeneity was tested with Cochran's Q test. A fixed effects model was used throughout for continuous variables, except where heterogeneity existed, in which case, a random effects model was used. Results are presented as weighted mean differences (WMD) with 95% confidence intervals (95% CI), where the difference between the treated and control groups was weighted by the inverse of the variance. Standardized mean differences (SMD) were calculated by dividing the difference between the treated and control by the baseline variance. SMD were used when different scales were used to measure the same concept. Dichotomous outcomes were analyzed with odds ratios. MAIN RESULTS: Five trials were included, with 170 subjects randomized to the placebo group receiving sham-TENS and 251 subjects receiving active TENS (153 for conventional mode, 98 for acupuncture-like TENS). The schedule of treatments varied greatly between studies ranging from one treatment/day for two consecutive days, to three treatments/day for four weeks. There were no statistically significant differences between the active TENS group when compared to the placebo TENS group for any outcome measures. Subgroup analysis performed on TENS application and methodological quality did not demonstrate a significant statistical difference. Remaining pre-planned subgroup analysis was not conducted due to the small number of included trials and the variety of outcome measures reported. REVIEWER'S CONCLUSIONS: The results of the meta-analysis present no evidence to support the use of TENS in the treatment of chronic low back pain. Clinicians and researchers should consistently report the characteristics of the TENS device and the application techniques used. New trials on TENS should make use of standardized outcome measures. This meta-analysis lacked data on how TENS effectiveness is affected by four important factors: type of applications, site of application, treatment duration of TENS, optimal frequencies and intensities.

Chronic Disease↗
PubMed1988

Low back pain: a comprehensive approach.

Back pain generally has a good prognosis. Most individuals with low back pain will not be seen by a physician. Symptoms will be resolved spontaneously with time. Patients who are seen with complaints of low back pain need a thorough history and physical examination, with appropriate additional studies as indicated. Conservative therapy will usually prove successful. Current trends in therapy are toward shorter periods of inactivity, with more emphasis on education and rehabilitation, to include active reconditioning in an attempt to decrease the risk of reinjury. For individuals with chronic back pain, referral to a multidisciplinary chronic pain center may be necessary.

Back Pain↗
PubMed2004

Spinal manipulative therapy for low back pain.

BACKGROUND: Low-back pain is a costly illness for which spinal manipulative therapy is commonly recommended. Previous systematic reviews and practice guidelines have reached discordant results on the effectiveness of this therapy for low-back pain. OBJECTIVES: To resolve the discrepancies related to the use of spinal manipulative therapy and to update previous estimates of effectiveness, by comparing spinal manipulative therapy with other therapies and then incorporating data from recent high-quality randomized, controlled trials (RCTs) into the analysis. SEARCH STRATEGY: The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL were electronically searched from their respective beginning to January 2000, using the Back Group search strategy; references from previous systematic reviews were also screened. SELECTION CRITERIA: Randomized, controlled trials (RCT) that evaluated spinal manipulative therapy for patients with low-back pain, with at least one day of follow-up, and at least one clinically-relevant outcome measure. DATA COLLECTION AND ANALYSIS: Two authors, who served as the reviewers for all stages of the meta-analysis, independently extracted data from unmasked articles. Comparison treatments were classified into the following seven categories: sham, conventional general practitioner care, analgesics, physical therapy, exercises, back school, or a collection of therapies judged to be ineffective or even harmful (traction, corset, bed rest, home care, topical gel, no treatment, diathermy, and minimal massage). MAIN RESULTS: Thirty-nine RCTs were identified. Meta-regression models were developed for acute or chronic pain and short-term and long-term pain and function. For patients with acute low-back pain, spinal manipulative therapy was superior only to sham therapy (10-mm difference [95% CI, 2 to 17 mm] on a 100-mm visual analogue scale) or therapies judged to be ineffective or even harmful. Spinal manipulative therapy had no statistically or clinically significant advantage over general practitioner care, analgesics, physical therapy, exercises, or back school. Results for patients with chronic low-back pain were similar. Radiation of pain, study quality, profession of manipulator, and use of manipulation alone or in combination with other therapies did not affect these results. REVIEWER'S CONCLUSIONS: There is no evidence that spinal manipulative therapy is superior to other standard treatments for patients with acute or chronic low-back pain.

Humans↗
PubMed2004

Greater trochanter bursitis pain syndrome in females with chronic low back pain and sciatica.

Trochanteric bursitis is a clinical condition which simulates major hip diseases and low back pain, it may also mimic nerve root pressure syndrome. Patients with greater trochanteric bursitis pain syndrome (GTBPS) usually suffer from pain radiating to the posterolateral aspect of the thigh, paraesthesiae in the legs, and tenderness over the iliotibial tract.. The purpose of this study is to indicate the similarity between the clinical features of the GTBPS and those of chronic low back pain, and to highlight the importance of diagnosing GTBPS in patients complaining of low back conditions. Three hundred female patients were included in this prospective study. All patients complained about chronic low back pain or sciatica and had a failed long term conservative treatment. Local injection of the tender peritrochanteric area was only done in half of the patients (group 1). Patients were required to answer the Oswestry Disability Index Questionnaire during all periods of follow-up. Patients of group 1 had a better clinical outcome (p < 0.0005) than the patients in group 2 where no injection was done. We conclude that greater trochanter bursitis pain syndrome is a frequent syndrome which may be associated with low back symptoms. Patients with a long standing history of low back pain and sciatica should be routinely checked for GTBPS. GTBPS is easy to diagnose and can be treated. Peritrochanteric infiltration with glucocorticoids mixed with 2% lidocaine relieves patients from their symptoms for a long period of time. Recurrence should always be expected, but treatment may be repeated.

Activities of Daily Living↗
PubMed1991

Common causes of low back pain in children.

Low back pain in children and adolescents is often caused by a serious problem. The diagnostic investigation should begin with a complete patient history, complete physical examination, laboratory testing, and plain radiography. These results should be used to direct further imaging studies. Although most of the painful injuries that children sustain in recreational activities are mild, back pain that lasts for extended periods may be due to various disorders, including spondylolysis and spondylolisthesis, disk herniation, Scheuermann disease, or neoplasms. Low back pain can also be caused by diskitis and osteomyelitis, most commonly found in children younger than 10 years old. Primary osseous neoplasms of the lumbar spine are uncommon, with Ewing sarcoma, aneurysmal bone cyst, benign osteoblastoma, and osteoid osteoma being the most common followed by primary lymphoma. These lesions occur more often between the ages of 5 and 20 years. Other causes of low back pain include spinal cord tumors (eg, ependymoma), congenital disorders of the spine (eg, scoliosis), and systemic disease (eg, sickle cell disease).

Adolescent↗
PubMed2002

Multidisciplinary bio-psycho-social rehabilitation for chronic low back pain.

BACKGROUND: Chronic low back pain is, in many countries, the main cause of long term disability in middle age. Patients with chronic low back pain are often referred for multidisciplinary treatment. Previous published systematic reviews on this topic included no randomised controlled trials and pooled together controlled and non-controlled studies. OBJECTIVES: To assess the effect of multidisciplinary bio-psycho-social rehabilitation on pain, function, employment, quality of life and global assessment outcomes in subjects with chronic disabling low back pain. SEARCH STRATEGY: We searched MEDLINE, EMBASE, PsychLIT, CINAHL, Health STAR, and The Cochrane Library from the beginning of the database to June 1998 using the comprehensive search strategy recommended by the Back Review Group of the Cochrane Collaboration. INTERVENTION specific key words for this review were: patient care team, patient care management, multidisciplinary, interdisciplinary, multiprofessional, multimodal, pain clinic and functional restoration. We also reviewed reference lists and consulted the editors of the Back Review Group of the Cochrane Collaboration. SELECTION CRITERIA DESIGN: randomised controlled trials comparing multidisciplinary bio-psycho-social rehabilitation with a non-multidisciplinary control intervention. POPULATION: Adults with disabling low back pain of more than three months in duration. INTERVENTION: Patients had to be assessed and treated by qualified professionals according to a plan that addresses physical and at least one of psychological, or social/occupational dimensions. OUTCOMES: Only trials which reported treatment effect in at least one of pain, function, employment status, quality of life or global improvement. Exclusion: Pure educational interventions (back schools) and pure physical interventions were excluded. DATA COLLECTION AND ANALYSIS: Selection, data extraction and quality grading of studies was done by two independent reviewers using pre-tested data forms. Study quality was assessed according to the scheme recommended by the Back Review Group of the Cochrane Collaboration. Trials with internal validity scores of five or more in a ten point scale were considered high quality. Discrepancies between reviewers were resolved by consensus or by a third reviewer. Given the marked heterogeneity in study settings, interventions and control groups we decided not to pool trial results in a meta-analysis. Instead, we summarized findings by strength of evidence and nature of intervention and control treatments. The evidence was judged to be strong when multiple high quality trials produced generally consistent findings. It was judged to be moderate when multiple low quality or one high quality and one or more low quality trials produced generally consistent findings. Evidence was considered to be limited when only one randomised trial existed or if findings of existing trials were inconsistent. MAIN RESULTS: Ten trials (12 randomised comparisons) were included. They randomised a total of 1964 patients with chronic low back pain. There was strong evidence that intensive multidisciplinary bio-psycho-social rehabilitation with a functional restoration approach improved function when compared with inpatient or outpatient non-multidisciplinary treatments. There was moderate evidence that intensive multidisciplinary bio-psycho-social rehabilitation with a functional restoration approach improved pain when compared with outpatient non-multidisciplinary rehabilitation or usual care. There was contradictory evidence regarding vocational outcomes of intensive multidisciplinary bio-psycho-social intervention. Some trials reported improvements in work readiness, but others showed no significant reduction in sickness leaves. Less intensive outpatient psycho-physical treatments did not improve pain, function or vocational outcomes when compared with non-multidisciplinary outpatient therapy or usual care. Few trials reported effects on quality of life or global assessments. REVIEWER'S CONCLUSIONS: The reviewed trials provide evidence that intensive multidisciplinary bio-psycho-social rehabilitation with a functional restoration approach improves pain and function. Less intensive interventions did not show improvements in clinically relevant outcomes.

Back Pain↗
PubMed2005

Radiofrequency lesioning of the L2 ramus communicans in managing discogenic low back pain.

BACKGROUND: Discogenic low back pain is a common cause of chronic low back pain that remains a treatment challenge. The innervation and transmission of nociceptive information from painful lumbar discs has only recently been better described. OBJECTIVE: To report initial experience of effectiveness of radiofrequency lesioning of L2 ramus communicans in managing discogenic pain. STUDY DESIGN: A prospective, case series. METHODS: A case series of 5 patients who had radiofrequency lesioning of the ramus communicans at the L2 level. All patients had discogenic low back pain and had diagnostic blocks with local anesthetic at the level of the L2 ramus communicans demonstrating significant pain relief. Continuous radiofrequency lesioning at 80 degrees C of the L2 ramus communicans for 60 seconds was performed. Standard outcome measures of reduction in the visual analogue scale (VAS), improvement in function, reduction in pain medication, and consistent improvement in low back pain with repeating of the procedure after its initial effect has worn off were recorded. RESULTS: All five patients had consistent pain relief after a minimum of 2 radiofrequency lesioning treatments approximately 4 months apart. Four of the five patients had a reduction in pain medication, and all reported improvement in sitting tolerance and functioning. There were no side effects or complications. CONCLUSION: Radiofrequency lesioning of the L2 ramus communicans seems to offer partial relief for patients suffering from discogenic pain. Further studies are needed to confirm our results.

Journal Article↗
PubMed2005

Evolutionary aspects and muscular properties of the trunk--implications for human low back pain.

Considerations about back pain, its aetiology, pathogenesis and therapy often argue that low back pain is the "price" that humanity has to pay for the upright body posture and the bipedal mode of locomotion. In fact, there are only few species that have evolved an obligate bipedal locomotion (e.g. kangaroos). Surprisingly, there are only minor morphological adaptations in humans clearly connected to the upright body posture (e.g. the habitual lumbar lordosis). The overall organization of the body axis has been evolved in quadrupedal animals and was more or less unchanged suitable for the human bipedal mode of locomotion. Up to now, the assumed uniqueness of human's trunk does not explain the frequency of back problems. Because of minor macroscopic differences between humans and other mammals, and even primates, we started to take a closer look at the paravertebral musculature. A three-dimensional investigation of muscle's fibre type distribution was undertaken on laboratory rats. Serial sections from the caudal thoracic and lumbar regions of the back were analysed, and the fibre type distribution pattern in all paravertebral muscles was described. Comparisons to other species imply more general characters of the fibre type distribution in mammals. Established concepts of human back muscle function were exposed to be valid for quadruped mammals as well. Muscle properties predicted by a biomechanical model based on human's anatomy (Wagner et al., this issue) were confirmed by results of the current study on a small mammal. Therefore, we propose only minor differences from the observed pattern in human back muscles.

Journal Article↗
PubMed2004

Evidence of augmented central pain processing in idiopathic chronic low back pain.

OBJECTIVE: For many individuals with chronic low back pain (CLBP), there is no identifiable cause. In other idiopathic chronic pain conditions, sensory testing and functional magnetic resonance imaging (fMRI) have identified the occurrence of generalized increased pain sensitivity, hyperalgesia, and altered brain processing, suggesting central augmentation of pain processing in such conditions. We compared the results of both of these methods as applied to patients with idiopathic CLBP (n = 11), patients with widespread pain (fibromyalgia; n = 16), and healthy control subjects (n = 11). METHODS: Patients with CLBP had low back pain persisting for at least 12 months that was unexplained by MRI/radiographic changes. Experimental pain testing was performed at a neutral site (thumbnail) to assess the pressure-pain threshold in all subjects. For fMRI studies, stimuli of equal pressure (2 kg) and of equal subjective pain intensity (slightly intense pain) were applied to this same site. RESULTS: Despite low numbers of tender points in the CLBP group, experimental pain testing revealed hyperalgesia in this group as well as in the fibromyalgia group; the pressure required to produce slightly intense pain was significantly higher in the controls (5.6 kg) than in the patients with CLBP (3.9 kg) (P = 0.03) or the patients with fibromyalgia (3.5 kg) (P = 0.006). When equal amounts of pressure were applied to the 3 groups, fMRI detected 5 common regions of neuronal activation in pain-related cortical areas in the CLBP and fibromyalgia groups (in the contralateral primary and secondary [S2] somatosensory cortices, inferior parietal lobule, cerebellum, and ipsilateral S2). This same stimulus resulted in only a single activation in controls (in the contralateral S2 somatosensory cortex). When subjects in the 3 groups received stimuli that evoked subjectively equal pain, fMRI revealed common neuronal activations in all 3 groups. CONCLUSION: At equal levels of pressure, patients with CLBP or fibromyalgia experienced significantly more pain and showed more extensive, common patterns of neuronal activation in pain-related cortical areas. When stimuli that elicited equally painful responses were applied (requiring significantly lower pressure in both patient groups as compared with the control group), neuronal activations were similar among the 3 groups. These findings are consistent with the occurrence of augmented central pain processing in patients with idiopathic CLBP.

Adult↗