Establishing Central Sensitization-Related Symptom Severity Subgroups: A Multicountry Study Using the Central Sensitization Inventory.

OBJECTIVES: The goal of this study was to identify central sensitization-related symptom severity subgroups in a large multicountry sample composed of patients with chronic pain and pain-free individuals using the Central Sensitization Inventory (CSI). METHODS: A large, pooled international (N = 8 countries) sample of chronic pain patients plus healthy subjects (total N = 2,620) was randomly divided into two subsamples for cross-validation purposes. First, a hierarchical cluster analysis (HCA) was performed using CSI item-level data as clustering variables (test sample; N = 1,312). Second, a latent profile analysis (LPA) was conducted to confirm the optimal number of CSI clusters (validation sample; N = 1,308). Finally, to promote implementation in real-world clinical practice, we built a free online Central Sensitization Inventory Symptom Severity Calculator. RESULTS: In both HCA (N = 1,219 valid cases) and LPA (N = 1,245 valid cases) analyses, a three-cluster and three-profile solution, respectively, emerged as the most statistically optimal and clinically meaningful. Clusters were labeled as follows: (i) Low Level of CS-Related Symptom Severity, (ii) Medium Level of CS-Related Symptom Severity, and (iii) High Level of CS-Related Symptom Severity. CONCLUSIONS: Our results indicated that a three-cluster solution clearly captured the heterogeneity of the CSI data. The calculator might provide an efficient way of classifying subjects into the cluster groups. Future studies should analyze the extent to which the CSI cluster classification correlates with other patient-reported and objective signs and symptoms of CS in patients with chronic pain, their associations with clinical outcomes, health-related costs, biomarkers, (etc.), and responsiveness to treatment.

Does the Length of Disability between Injury and Functional Restoration Program Entry Affect Treatment Outcomes for Patients with Chronic Disabling Occupational Musculoskeletal Disorders?

Purpose Functional restoration programs (FRPs), for patients with chronic disabling occupational musculoskeletal disorders (CDOMDs), have consistently demonstrated positive socioeconomic treatment outcomes, including decreased psychosocial distress and increased work return. The pre-treatment length of disability (LOD), or time between injury and treatment admission, has been shown to influence FRP work outcomes. Some studies have found that shorter LOD is associated with better work outcomes. However, few studies have actually examined cohorts with LOD duration longer than 18 months. This present study evaluated the effects of extended LOD (beyond 18 months) on important treatment outcomes. Methods A total cohort of 1413 CDOMD patients entered an FRP. Of those, 312 did not complete the program, so they were eliminated from outcome analyses. The 1101 patients who completed the FRP were classified based on LOD: Late Rehabilitation (LR, 3-6 months, n = 190); Chronic Disability (CD, 7-17 months, n = 494); and Late Chronic Disability (LCD). The LCD, in turn, consisted of four separate subgroups: 18-23 months (LCD-18, n = 110); 24-35 months (LCD-24, n = 123); 36-71 months (LCD-36, n = 74); and 72+ months (LCD-72, n = 110). Patients were evaluated upon admission and were reassessed at discharge. Those patients who chose to pursue work goals post-treatment (n = 912) were assessed 1-year later. Results Longer LOD was associated with less likelihood of completing the FRP (p < .001). Compared to the other LOD groups, a relatively large percentage of patients (47%) in the longest- disability group were receiving social security disability benefits. Associations were found between longer LOD and more severe patient-reported pain, disability, and depressive symptoms at treatment admission. At discharge, symptom severity decreased for these patient-reported variables in all LOD groups (p < .001). Using binary logistic regressions, it was found that LOD significantly predicted work-return (Wald = 11.672, p = .04) and work-retention (Wald = 11.811, p = .04) after controlling for covariates. Based on the LOD groups, the percentage of patients returning to, and retaining work, ranged from 75.6 to 94.1%, and from 66.7 to 86.3%, respectively. The odds of LCD-24 and LCD-72 patients returning to work were 2.9, and 7.4, respectfully, less likely, compared to LR patients. Furthermore, the odds of LCD-24 and LCD-72 patients retaining work were 3.3 and 3.8 times, respectively, less likely, compared to LR patients. Conclusions Long LOD was a risk factor for FRP non-completion, and was associated with more severe patient-reported variables, including pain intensity and perceived disability. Furthermore, long LOD was a significant predictor for work outcomes at 1 year following FRP discharge. Nevertheless, a large percentage of longer LOD (>24 months) patients had returned to work within the year after discharge (above 85%), and had retained at least part-time work 1-year later (above 66%). These results support the effectiveness of the FRP in mitigating the effects of extended LOD in a large percentage of long-term LOD patients.

Establishing Clinically Relevant Severity Levels for the Central Sensitization Inventory.

OBJECTIVES: The aim of this study was to create and validate severity levels for the central sensitization inventory (CSI), a valid and reliable patient-reported outcome instrument designed to identify patients whose presenting symptoms may be related to a central sensitivity syndrome (CSS; eg, fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome), with a proposed common etiology of central sensitization (CS). METHODS: Based on CSI score means and standard deviations from previously published subject samples, the following CSI severity levels were established: subclinical = 0 to 29; mild = 30 to 39; moderate = 40 to 49; severe = 50 to 59; and extreme = 60 to 100. The concurrent validity of the CSI severity levels was then confirmed in a separate chronic pain patient sample (58% with a CSS diagnosis and 42% without) by demonstrating associations between CSI scores and (1) the number of physician-diagnosed CSSs; (2) CSI score distributions in both CSS and non-CSS patient samples; (3) patient-reported history of CSSs; and (4) patient-reported psychosocial measures, which are known to be associated with CSSs. RESULTS: Compared to the non-CSS patient subsample, the score distribution of the CSS patient subsample was skewed toward the higher severity ranges. CSI mean scores moved into higher severity levels as the number of individual CSS diagnoses increased. Patients who scored in the extreme CSI severity level were more likely to report previous diagnoses of fibromyalgia, chronic fatigue syndrome, temporomandibular joint disorder, tension/migraine headaches, and anxiety or panic attacks (P < 0.01). CSI severity levels were also associated with patient-reported depressive symptoms, perceived disability, sleep disturbance, and pain intensity (P ≤ 0.02). CONCLUSION: This study provides support for these CSI severity levels as a guideline for healthcare providers and researchers in interpreting CSI scores and evaluating treatment responsiveness.

The Fear-avoidance Components Scale (FACS): Development and Psychometric Evaluation of a New Measure of Pain-related Fear Avoidance.

Pain-related fear avoidance (FA), a common problem for patients with painful medical conditions, involves pain-related catastrophizing cognitions, hypervigilance, and avoidance behaviors, which can ultimately lead to decreased functioning, depression, and disability. Several patient-reported instruments have been developed to measure FA, but they have been criticized for limited construct validity, inadequate item specificity, lack of cutoff scores, and missing important FA components. The Fear-Avoidance Components Scale (FACS) is a new patient-reported measure designed to comprehensively evaluate FA in patients with painful medical conditions. It combines important components of FA found in prior FA scales, while trying to correct some of their deficiencies, within a framework of the most current FA model. Psychometric evaluation of the FACS found high internal consistency (α = 0.92) and high test/retest reliability (r = 0.90-0.94, P < 0.01). FACS scores differentiated between 2 separate chronic pain patient samples and a nonpatient comparison group. When clinically relevant severity levels were created, FACS severity scores were highly associated with FA-related patient-reported psychosocial and objective lifting performance variables. These results suggest that the FACS is a psychometrically strong and reliable measure that can help healthcare providers assess FA-related barriers to function and recovery.

The Potential Utility of the Patient Health Questionnaire as a Screener for Psychiatric Comorbidity in a Chronic Disabling Occupational Musculoskeletal Disorder Population.

OBJECTIVES: The patient health questionnaire (PHQ) is designed for screening psychopathology in primary care settings. However, little is known about its clinical utility in other chronic pain populations, which usually have high psychiatric comorbidities. DESIGN: A consecutive cohort of 546 patients with chronic disabling occupational musculoskeletal disorder (CDOMD) was administered and compared upon psychosocial assessments, including the PHQ and a structured clinical interview for DSM-IV (SCID). Four PHQ modules were assessed: major depressive disorder (MDD), generalized anxiety disorder (GAD), panic disorder (PD), and alcohol use disorders (AUD) [including both alcohol abuse and dependence]. Based on the SCID diagnosis, sensitivity and specificity were determined. RESULTS: The specificity of the PHQ ranged from moderate to high for all 4 PHQ modules (MDD, 0.79; GAD, 0.67; PD, 0.89; AUD, 0.97). However, the sensitivity was relatively low: MDD (0.58); GAD (0.61); PD (0.49); and AUD (0.24). The PHQ was also associated with psychosocial variables. Patients whose PHQ showed MDD, GAD, or PD reported significantly more depressive symptoms and perceived disability than patients who did not (Ps < 0.001). Patients with MDD or GAD reported significantly higher pain than those without (Ps < 0.001). CONCLUSIONS: The strong specificity of the PHQ appears to be its primary strength for this cohort. Due to its high specificity, the PHQ could be employed as an additional screening tool to help rule out potential psychiatric comorbidity in patients with CDOMD. The low sensitivity of the PHQ in this population, however, remains a weakness of the PHQ.

Cost-effectiveness of early versus delayed functional restoration for chronic disabling occupational musculoskeletal disorders.

PURPOSE: Despite extensive evidence for the treatment effectiveness of interdisciplinary functional restoration (FR) for chronic disabling occupational musculoskeletal disorders (CDOMD), there is little documentation on the cost-effectiveness of early rehabilitation using FR. METHODS: A total of 1,119 CDOMD patients were classified according to duration of disability on FR entry, corresponding to early rehabilitation (ER: 4-8 months of disability, N = 373), intermediate duration (ID: 9-18 months, N = 373), and delayed rehabilitation (DR: >18 months, N = 373). Groups were matched on sex, age, ethnicity, and injured musculoskeletal region. One-year post-rehabilitation outcomes included return-to-work, work retention and healthcare utilization. Economic analyses included a cost-effectiveness analysis of the FR program, and estimation of the total cost-of-illness. RESULTS: At 1-year post-rehabilitation, all groups were comparable on return-to-work (overall 88%), work retention (overall 80%), and additional healthcare utilization (overall, 2.2% of patients received re-operations/new surgeries, 2 visits to new healthcare provider). Savings of up to 64% in medical costs, and up to 80% in disability benefits and productivity losses was associated with the ER group. The cost of rehabilitation was also up to 56% lower when administered early. Overall, ER resulted in estimated cost savings of up to 72% (or almost $170,000 per claim). CONCLUSIONS: Duration of disability does not negatively impact objective work or healthcare utilization outcomes following interdisciplinary FR. However, early rehabilitation is more likely to be a cost-effective solution compared to cases that progress >8 months and receiving FR as a treatment of "last resort".

Does the economy affect functional restoration outcomes for patients with chronic disabling occupational musculoskeletal disorders?

PURPOSE: To determine how the economy affects psychosocial and socioeconomic treatment outcomes in a cohort of chronic disabling occupational musculoskeletal disorder (CDOMD) patients who completed a functional restoration program (FRP). METHODS: A cohort of 969 CDOMD patients with active workers' compensation claims completed an FRP (a medically-supervised, quantitatively-directed exercise progression program, with multi-modal disability management). A good economy (GE) group (n = 532) was released to work during a low unemployment period (2005-2007), and a poor economy (PE) group (n = 437) was released during a higher unemployment period (2008-2010). Patients were evaluated upon admission for demographic and psychosocial variables, and were reassessed at discharge. Socioeconomic outcomes, including work return and work retention 1 year post-discharge, were collected. RESULTS: Some significant differences in psychosocial self-report data were found, but most of the effect sizes were small, so caution should be made when interpreting the data. Compared to the PE group, the GE group reported more depressive symptoms and disability at admission, but demonstrated a larger decrease in depressive symptoms and disability and increase in self-reported quality of life at discharge. The PE group had lower rates of work return and retention 1-year after discharge, even after controlling for other factors such as length of disability and admission work status. CONCLUSIONS: CDOMD patients who completed an FRP in a PE year were less likely to return to, or retain, work 1-year after discharge, demonstrating that a PE can be an additional barrier to post-discharge work outcomes. A difference in State unemployment rates of <3% (7 vs. 5%) had a disproportionate effect on patients' failure to return to (19 vs. 6%) or retain (28 vs. 15%) work.

The clinical utility of the Multidimensional Pain Inventory (MPI) in characterizing chronic disabling occupational musculoskeletal disorders.

PURPOSE: The Multidimensional Pain Inventory (MPI) was designed to help capture unique characteristics of chronic pain patients. The present study examined the proportion of subgroups classified by the MPI in a chronic disabling occupational musculoskeletal disorder (CDOMD) patient cohort, and described characteristics of MPI profile groups in terms of other psychosocial variables. METHODS: A cohort of 1,270 CDOMD patients undergoing an interdisciplinary functional restoration program was studied. Before the start of the program, all patients received a standard psychosocial assessment battery. A MPI computer program scored and identified pre-defined MPI subgroups: Adaptive Coper (AC); Interpersonally Distressed (ID); and Dysfunctional (DYS). RESULTS: The distribution of MPI profiles for CDOMD patients was similar with those of highly disabled patients, with the largest proportion of patients having the DYS profile (44 %), followed by AC (33 %) and ID (23 %). The DYS profile group showed the highest level of pain severity, and psychosocial distress; the ID group had a moderate level; and the AC profile group had the lowest level. Higher rates of psychiatric disorders were also found in the DYS and ID groups. The DYS profile group was less likely to complete the treatment program. CONCLUSION: The present study further demonstrated the clinical utility of the MPI classification in a large cohort of CDOMD patients, indicating that the MPI profiles successfully distinguish among patients who may require extra psychosocial attention to achieve successful treatment gains and program completion.

Prediction of failure to retain work 1 year after interdisciplinary functional restoration in occupational injuries.

OBJECTIVE: To identify risk factors for work retention (a patients' ability to both obtain and retain employment) at 1 year after treatment for a chronic disabling occupational musculoskeletal disorder (CDOMD). DESIGN: Prospective cohort study. SETTING: Consecutive patients undergoing interdisciplinary functional restoration treatment in a regional rehabilitation referral center. PARTICIPANTS: A sample of 1850 consecutive CDOMD patients, who were admitted to and completed a functional restoration program, were subsequently classified as work retention or nonwork retention at a 1-year posttreatment evaluation. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Measures, including medical evaluations, demographic and occupational data, psychosocial diagnostic evaluation, and validated measures of pain, disability, and depressive symptoms, were obtained at admission to, and discharge from, the program. RESULTS: Using a multivariate logistic regression analysis, the following variables were found to be significant predictors of failure to retain work: older age (odds ratio [OR]=1.84; 95% confidence interval [CI], 1.33-2.54), female sex (OR=1.46; 95% CI, 1.09-1.94), nonworking status at discharge (OR=1.65; 95% CI, 1.11-2.45), extreme disability at admission (OR=1.46; 95% CI, 1.06-2.00), antisocial personality disorder (OR=2.11; 95% CI, 1.09-4.08), receipt of government disability benefits at admission (OR=2.28; 95% CI, 1.06-4.89), and dependence on opiate pain medications (OR=1.43; 95% CI, 1.02-2.00). The final model improved prediction by 75% over assigning all patients to the larger (work retention) group. CONCLUSIONS: This study identified demographic, psychosocial, and occupational factors that were predictive of failure to retain work. These risk factors may be used to individualize treatment plans for CDOMD patients in order to provide optimal functional restoration.

The development and psychometric validation of the central sensitization inventory.

Central sensitization (CS) has been proposed as a common pathophysiological mechanism to explain related syndromes for which no specific organic cause can be found. The term "central sensitivity syndrome (CSS)" has been proposed to describe these poorly understood disorders related to CS. The goal of this investigation was to develop the Central Sensitization Inventory (CSI), which identifies key symptoms associated with CSSs and quantifies the degree of these symptoms. The utility of the CSI, to differentiate among different types of chronic pain patients who presumably have different levels of CS impairment, was then evaluated. Study 1 demonstrated strong psychometric properties (test-retest reliability = 0.817; Cronbach's alpha = 0.879) of the CSI in a cohort of normative subjects. A factor analysis (including both normative and chronic pain subjects) yielded 4 major factors (all related to somatic and emotional symptoms), accounting for 53.4% of the variance in the dataset. In Study 2, the CSI was administered to 4 groups: fibromyalgia (FM); chronic widespread pain without FM; work-related regional chronic low back pain (CLBP); and normative control group. Analyses revealed that the patients with FM reported the highest CSI scores and the normative population the lowest (P < 0.05). Analyses also demonstrated that the prevalence of previously diagnosed CSSs and related disorders was highest in the FM group and lowest in the normative group (P < 0.001). Taken together, these 2 studies demonstrate the psychometric strength, clinical utility, and the initial construct validity of the CSI in evaluating CS-related clinical symptoms in chronic pain populations.

Time to drink: Activating lateral hypothalamic area neurotensin neurons promotes intake of fluid over food in a time-dependent manner.

The lateral hypothalamic area (LHA) is essential for ingestive behavior but has primarily been studied in modulating feeding, with comparatively scant attention on drinking. This is partly because most LHA neurons simultaneously promote feeding and drinking, suggesting that ingestive behaviors track together. A notable exception are LHA neurons expressing neurotensin (LHANts neurons): activating these neurons promotes water intake but modestly restrains feeding. Here we investigated the connectivity of LHANts neurons, their necessity and sufficiency for drinking and feeding, and how timing and resource availability influence their modulation of these behaviors. LHANts neurons project broadly throughout the brain, including to the lateral preoptic area (LPO), a brain region implicated in modulating drinking behavior. LHANts neurons also receive inputs from brain regions implicated in sensing hydration and energy status. While activation of LHANts neurons is not required to maintain homeostatic water or food intake, it selectively promotes drinking during the light cycle, when ingestive drive is low. Activating LHANts neurons during this period also increases willingness to work for water or palatable fluids, regardless of their caloric content. By contrast, LHANts neuronal activation during the dark cycle does not promote drinking, but suppresses feeding during this time. Finally, we demonstrate that the activation of the LHANts â†’ LPO projection is sufficient to mediate drinking behavior, but does not suppress feeding as observed after generally activating all LHANts neurons. Overall, our work suggests how and when LHANts neurons oppositely modulate ingestive behaviors.

The Pain Anxiety Symptoms Scale fails to discriminate pain or anxiety in a chronic disabling occupational musculoskeletal disorder population.

BACKGROUND: The Pain Anxiety Symptoms Scale (PASS) was developed to measure fear and anxiety responses to pain. Many studies have found associations between PASS scores and self-report measures of pain, anxiety, and disability as well as among inhibited movement patterns and activity avoidance behaviors (eg, kinesophobia). This study aimed to identify clinically meaningful cut-off points to identify high or low levels of pain anxiety and to determine if the PASS provides additional useful information in a functional restoration (FR) treatment program for chronic disabling occupational musculoskeletal disorder (CDOMD) patients. METHODS: A consecutive cohort of 551 patients with CDOMD, who entered and completed a FR program, was administered a battery of psychosocial assessments, including the PASS, at admission and discharge. Socioeconomic outcomes were collected 1 year after discharge. After identifying clinical ranges for mild, moderate, and severe pain anxiety, the three groups were compared on self-report measures of psychosocial distress, clinical diagnoses of psychosocial disorders, and 1-year socioeconomic outcomes. RESULTS: Correlations between the PASS and all measures of pain, anxiety, and disability were statistically significant. However, only the Pain Disability Questionnaire showed a large correlation coefficient (r > 0.5). Patients with the highest PASS scores were more likely to be diagnosed with a number of Axis I (depression, opioid dependence) or Axis II (Borderline Personality) psychiatric disorders. They were more likely to display treatment-seeking behavior at 1 year after discharge. However, the PASS failed to differentiate between any other 1-year outcomes. CONCLUSIONS: The PASS is elevated when other measures of psychosocial distress are also elevated. However, the PASS fails to discriminate between different indices of depression and anxiety and it is not highly related to 1-year outcomes in a CDOMD cohort. If time and resources are limited, a different measure of psychosocial distress that does relate to socioeconomic outcomes might be a better option in a CDOMD evaluation process.

Invasive Treatments for Low Back Disorders.

OBJECTIVE: This abbreviated version of the American College of Occupational and Environmental Medicine's Low Back Disorders guideline reviews the evidence and recommendations developed for invasive treatments used to manage low back disorders. METHODS: Comprehensive systematic literature reviews were accomplished with article abstraction, critiquing, grading, evidence table compilation, and guideline finalization by a multidisciplinary expert panel and extensive peer-review to develop evidence-based guidance. Consensus recommendations were formulated when evidence was lacking and often relied on analogy to other disorders for which evidence exists. A total of 47 high-quality and 321 moderate-quality trials were identified for invasive management of low back disorders. RESULTS: Guidance has been developed for the invasive management of acute, subacute, and chronic low back disorders and rehabilitation. This includes 49 specific recommendations. CONCLUSION: Quality evidence should guide invasive treatment for all phases of managing low back disorders.

Non-Invasive and Minimally Invasive Management of Low Back Disorders.

OBJECTIVE: This abbreviated version of the American College of Occupational and Environmental Medicine's (ACOEM) Low Back Disorders Guideline reviews the evidence and recommendations developed for non-invasive and minimally invasive management of low back disorders. METHODS: Systematic literature reviews were accomplished with article abstraction, critiquing, grading, evidence table compilation, and guideline finalization by a multidisciplinary expert panel and extensive peer-review to develop evidence-based guidance. Consensus recommendations were formulated when evidence was lacking. A total of 70 high-quality and 564 moderate-quality trials were identified for non-invasive low back disorders. Detailed algorithms were developed. RESULTS: Guidance has been developed for the management of acute, subacute, and chronic low back disorders and rehabilitation. This includes 121 specific recommendations. CONCLUSION: Quality evidence should guide treatment for all phases of managing low back disorders.

Patients with chronic disabling occupational musculoskeletal disorder failing to complete functional restoration: analysis of treatment-resistant personality characteristics.

OBJECTIVE: To identify the risk factors for noncompletion of a functional restoration program for patients with chronic disabling occupational musculoskeletal disorders. DESIGN: Prospective cohort study. SETTING: Consecutive patients undergoing functional restoration treatment in a regional rehabilitation referral center. PARTICIPANTS: A sample of 3052 consecutive patients, classified as either completers (n=2367) or noncompleters (n=685), who entered a functional restoration program. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The measures used included medical evaluations, demographic data, Diagnostic and Statistical Manual of Mental Disorders psychiatric diagnoses, the Minnesota Multiphasic Personality Inventory, and validated questionnaires evaluating pain, depression, and occupational factors. RESULTS: The findings revealed that patients who did not complete the program had a longer duration of total disability between injury and admission to treatment (completers=20mo vs noncompleters=13mo; P<.001). Furthermore, patients who were opioid-dependent were 1.5 times more likely to drop out of rehabilitation, and patients diagnosed with a socially problematic Cluster B Personality Disorder were 1.6 times more likely to drop out. CONCLUSIONS: Although some risk factors associated with program noncompletion may be addressed in treatment, socially maladaptive personality disorders, long-neglected disability, and chronic opioid dependence are the major barriers to successful treatment completion. The patients identified with personality disorders may display resistance to treatment and may be difficult for the treatment staff to deal with. Early recognition of these treatment-resistant personality characteristics in the functional restoration process may assist the treatment team in developing more effective strategies to help this dysfunctional group.

Differential expression of nicotine withdrawal as a function of developmental age in the rat.

Cigarette smoking and resultant nicotine dependence remain major public health problems. Most smokers begin before the age of 18, yet preclinical models have insufficiently characterized the development of nicotine dependence in adolescence. To categorize the short-term effects of chronic nicotine administration throughout adolescence and adulthood, we exposed male Sprague Dawley rats to 14 days of continuously delivered nicotine (0, 1.2 or 4.8 mg/kg/d) using a subcutaneous osmotic minipump, starting between postnatal day 33 (p33) and p96. Next, to explore the effects of extended exposure to chronic nicotine, we exposed male Sprague Dawley rats to 42 days of continuous nicotine starting in adolescence (p33) or early adulthood (p68). Somatic and affective signs of precipitated withdrawal (PW) were observed after a mecamylamine (1.5 mg/kg, i.p.) challenge as compared to a saline injection. Short term nicotine exposure starting at p96, well within the adult period, elicited a significant increase in somatic PW as measured by a composite behavioral score. In contrast, adolescent exposure to nicotine elicited a unique behavioral profile, dependent on the starting age of exposure. Late adolescence exposure was characterized by scratching while adult exposure was characterized by facial tremors and yawns. Extended exposure to nicotine resulted in age specific characteristic nicotine withdrawal behaviors, including scratches, ptosis and locomotion, distinct from the short-term exposure. Thus, nicotine dependence severity, based on the expression of total somatic PW behaviors, is not observed until the adult period, and differences between adolescents and adults are observed using a more nuanced behavioral scoring approach. We conclude that age of nicotine initiation affects somatic withdrawal signs and their magnitude. These data serve as a foundation for understanding the underlying brain mechanisms of nicotine dependence and their development over adolescence and early adulthood.

Diagnostic Tests for Low Back Disorders.

OBJECTIVE: The aim of this study was to summarize evidence-based diagnostic guidelines for low back disorders. METHODS: A comprehensive literature review was conducted. A total of 101 articles of high or moderate quality addressing low back disorders diagnostic evaluation met the inclusion criteria. Evidence-based recommendations were developed and graded from (A) to (C) in favor and against the specific diagnostic test, with (A) level having the highest quality body of literature. Expert consensus was employed for insufficient evidence (I) to develop consensus guidance. RESULTS: Recommendations are given for these diagnostic tests: functional capacity evaluations, roentgenograms (x-rays), magnetic resonance imaging (MRI), computerized tomography, myelography, bone scans, single proton emission computed tomography, electromyography, surface electromyography, ultrasound, thermography, fluoroscopy, videofluoroscopy, lumbar discography, MRI discography, and myeloscopy. CONCLUSION: Diagnostic testing is not indicated for the majority of patients with low back pain.

Evidence-informed management of chronic low back pain with functional restoration.

The management of chronic low back pain (CLBP) has proven to be very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing amongst available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence-Informed Management of Chronic Low Back Pain Without Surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.

Psychological evaluation of the spine patient.

The biopsychosocial perspective focuses on the interaction among biologic, psychological, and medicolegal variables of patients coping with a persistent medical condition. It is considered the most comprehensive and heuristic approach to psychological evaluation in the spine patient. Assessment proceeds in three steps, from global indices of emotional distress to evaluation of more specific diagnoses of psychopathology. Step 1, the initial screening, uses psychometrically sound instruments to determine the level of patient distress. Step 2, the psychosocial interview, indicates whether additional psychological testing is needed. Step 3, the presurgical evaluation, assesses patients being considered for a surgical procedure. This stepwise assessment approach significantly aids in yielding evidence-based outcomes as well as in identifying the patient who may be most recalcitrant to treatment intervention.

Dimensionality and Reliability of the Central Sensitization Inventory in a Pooled Multicountry Sample.

Central sensitization (CS) involves the amplification of neural signaling within the central nervous system, which evokes pain hypersensitivity. The Central Sensitization Inventory (CSI) assesses 25 overlapping health-related symptom dimensions that have been reported to be associated with CS-related disorders. Previous studies have reported satisfactory test-retest reliability and internal consistency, but factor analyses have exhibited conflicting results in different language versions. The purpose of this cross-sectional study was to thoroughly examine the dimensionality and reliability of the CSI, with pooled data from 1,987 individuals, collected in several countries. The principal component analysis suggested that 1 general factor of CS best described the structure. A subsequent confirmatory factor analysis revealed that a bifactor model, which accounted for the covariance among CSI items, with regard to 1 general factor and 4 orthogonal factors, fit the CSI structure better than the unidimensional and the 4-factor models. Additional analyses indicated substantial reliability for the general factor (ie, Cronbach α = .92; ω = .95; and ω hierarchical = .89). Reliability results for the 4 specific factors were considered too low to be used for subscales. The results of this study clearly suggest that only total CSI scores should be used and reported. PERSPECTIVE: As far as we know, this is the first study that has examined the factor structure and reliability of the CSI in a large multicountry sample. The CSI is currently considered the leading self-report measure of CS-related symptoms worldwide.