Assessment of pain in sedated and mechanically ventilated patients: an observational study

Critically ill patients often undergo unpleasant procedures. We quantified the effects of an unpleasant stimulus on physiological and behavioral parameters and evaluated how they are modified by sedation and analgesia.

[Assessment of musculoskeletal pain]

The rationale for a successful treatment of musculoskeletal pain is an adequate initial assessment. Standardized questionnaires, modern imaging modalities such as computed tomography, magnetic resonance imaging and musculoskeletal ultrasound or electrophysiology have enriched our armamentarium in the last decades. Pain inducing pathologies can often be identified and treated in a targeted way due to these procedures. But none of these techniques allows an adequate judgment of the acquired findings. Supplementary tests have to be indicated and interpreted in the context of the patient's entire history and the clinical findings. These two remain to be the cornerstones of the assessment of painful musculoskeletal disorders.

A pain assessment scale for population-based studies: Development and validation of the Pain Module of the Standard Evaluation Questionnaire

The objectives of this study were to develop and validate a tool for assessing pain in population-based observational studies and to develop three subscales for back/neck, upper extremity and lower extremity pain. Based on a literature review, items were extracted from validated questionnaires and reviewed by an expert panel. The initial questionnaire consisted of a pain manikin and 34 items relating to (i) intensity of pain in different body regions (7 items), (ii) pain during activities of daily living (18 items) and (iii) various pain modalities (9 items). Psychometric validation of the initial questionnaire was performed in a random sample of the German-speaking Swiss population. Analyses included tests for reliability, correlation analysis, principal components factor analysis, tests for internal consistency and validity. Overall, 16,634 of 23,763 eligible individuals participated (70%). Test-retest reliability coefficients ranged from 0.32 to 0.97, but only three coefficients were below 0.60. Subscales were constructed combining four items for each of the subscales. Item-total coefficients ranged from 0.76 to 0.86 and Cronbach's alpha were 0.75 or higher for all subscales. Correlation coefficients between subscales and three validated instruments (WOMAC, SPADI and Oswestry) ranged from 0.62 to 0.79. The final Pain Standard Evaluation Questionnaire (SEQ Pain) included 28 items and the pain manikin and accounted for the multidimensionality of pain by assessing pain location and intensity, pain during activity, triggers and time of onset of pain and frequency of pain medication. It was found to be reliable and valid for the assessment of pain in population-based observational studies.

In vivo assessment of HCN channel current (I(h)) in human motor axons

The "Trond" protocol of nerve excitability tests has been used widely to assess axonal function in peripheral nerve. In this study, the routine Trond protocol was expanded to refine assessment of cAMP-dependent, hyperpolarization-activated current (I(h)) activity. I(h) activity is generated by hyperpolarization-activated, cyclic nucleotide-modulated (HCN) channels in response to hyperpolarization. It limits activity-dependent hyperpolarization, contributes to neuronal automaticity, and is implicated in chronic pain states. Published data regarding I(h) activity in motor nerve are scant. We used additional strong, prolonged hyperpolarizing conditioning stimuli in the threshold electrotonus component of the Trond protocol to demonstrate the time-course of activation of I(h) in motor axons. Fifteen healthy volunteers were tested on four occasions during 1 week. I(h) action was revealed in the threshold electrotonus by the limiting and often reversal, after about 100 ms, of the threshold increase caused by strong hyperpolarizing currents. Statistical analysis by repeated-measures analysis of variance enabled confidence limits to be established for variation between subjects and within subjects. The results demonstrate that, of all the excitability parameters, those dependent on I(h) were the most characteristic of an individual, because variance between subjects was more than four times the variance within subjects. This study demonstrates a reliable method for in vivo assessment of I(h,) and also serves to document the normal variability in nerve excitability properties within subjects.

Quantitative assessment of physiological and behavioural parameters in healthy dairy cows evoked by transcutaneous electrical nerve stimulation of the udder

The pain and distress associated with transcutaneous electrical nerve stimulation (TENS) of the udder was evaluated by treating 20 healthy dairy cows with an electrical udder stimulator. This generated a sequence of pulses (frequency: 160+/-10% impulses per second, duration 250 mus) and provided voltage ranges from 0 to 10 volts (+/-10%). Trials took place on three consecutive days, twice daily after morning and evening milking. Daily sessions were divided into two periods: (1) control (sham treatment) and (2) treatment (real treatment). Physiological (heart rate, respiratory rate, and plasma cortisol concentration) as well as ethological parameters (kicking, weight shifting, and looking backwards to udder) were defined as pain-indicating parameters and observed. Evaluation of data showed that only one parameter (kicking) was significantly increased during real treatment compared to sham treatment. It is concluded that the TENS therapy tested in this study can evoke changes in behaviour (increased kicking) consistent with an experience of pain in some cows.

Clinical and radiographic assessment of various predictors for healing outcome 1 year after periapical surgery

This clinical study prospectively evaluated the influence of various predictors on healing outcome 1 year after periapical surgery. The study cohort included 194 teeth in an equal number of patients. Three teeth were lost for the follow-up (1.5% drop-out rate). Clinical and radiographic measures were used to determine the healing outcome. For statistical analysis, results were dichotomized (healed versus nonhealed). The overall success rate was 83.8% (healed cases). The only individual predictors to prove significant for the outcome were pain at initial examination (p=0.030) and other clinical signs or symptoms at initial examination (p=0.042), meaning that such teeth had lower healing rates 1 year after periapical surgery compared with teeth without such signs or symptoms. Logistic regression revealed that pain at initial examination (odds ratio=2.59, confidence interval=1.2-5.6, p=0.04) was the only predictor reaching significance. Several predictors almost reached statistical significance: lesion size (p=0.06), retrofilling material (p=0.06), and postoperative healing course (p=0.06).

The self-administered 24-item geriatric pain measure (GPM-24-SA): psychometric properties in three European populations of community-dwelling older adults

OBJECTIVE: To explore the feasibility and psychometric properties of a self-administered version of the 24-item Geriatric Pain Measure (GPM-24-SA). DESIGN: Secondary analysis of baseline data from the Prevention in Older People-Assessment in Generalists' practices trial, an international multi-center study of a health-risk appraisal system. PARTICIPANTS: One thousand seventy-two community dwelling nondisabled older adults self-reporting pain from London, UK; Hamburg, Germany; and Solothurn, Switzerland. OUTCOME MEASURES: GPM-24-SA as part of a multidimensional Health Risk Appraisal Questionnaire including self-reported demographic and health-related information. RESULTS: Among the 1,072 subjects, 655 had complete GPM-24-SA data, 404 had 30% missing GPM-24-SA data. In psychometric analyses across the three European populations with complete GPM-24-SA data, the measure exhibited stable internal consistency, good convergent, divergent and discriminant validity, and produced stable pain measurements. However, factor analysis indicated differences in the GPM-24-SA across sites with discrepancies mainly related to items of a single subscale that failed to load appropriately. Analyses including imputation for subjects with assessment of pain in community dwelling older adults. However, because of incomplete response and uncertainty in factor structure, further refinement and psychometric evaluation of the GPM-24-SA is needed before it could be recommended for widespread use.

Assessment of osteoarthritis in hips with femoroacetabular impingement using delayed gadolinium enhanced MRI of cartilage

PURPOSE: To determine the feasibility of assessing early osteoarthritis (OA) in hips with femoroacetabular impingement (FAI) using delayed Gadolinium enhanced MRI of Cartilage (dGEMRIC). MATERIALS AND METHODS: Thirty-seven hips in 30 patients who had a dGEMRIC scan and radiographic evidence of FAI were identified. Clinical symptoms were assessed. Radiographic measurements were performed to determine acetabular and femoral morphology. The severity of radiographic OA was determined using Tönnis grade and minimum joint space width (JSW). On MRI, the alpha angle was measured on the sagittal oblique slices. Correlations between dGEMRIC index, patient symptoms, morphologic measurements, radiographic OA, and age were determined. RESULTS: Significant correlations were observed between dGEMRIC index, pain (P < 0.05), and alpha angle (P < 0.05). The correlation of dGEMRIC with alpha angle suggests that hips with more femoral deformity show signs of early OA. CONCLUSION: The results of osteoplasty for FAI depend on the amount of pre-existing OA in the joint. dGEMRIC may be a useful technique for diagnosis and staging of early osteoarthritis in hips with impingement.

SWISSspine: a nationwide registry for health technology assessment of lumbar disc prostheses

SWISSspine is a so-called pragmatic trial for assessment of safety and efficiency of total disc arthroplasty (TDA). It follows the new health technology assessment (HTA) principle of "coverage with evidence development". It is the first mandatory HTA registry of its kind in the history of Swiss orthopaedic surgery. Its goal is the generation of evidence for a decision by the Swiss federal office of health about reimbursement of the concerned technologies and treatments by the basic health insurance of Switzerland. During the time between March 2005 and 2008, 427 interventions with implantation of 497 lumbar total disc arthroplasties have been documented. Data was collected in a prospective, observational multicenter mode. The preliminary timeframe for the registry was 3 years and has already been extended. Data collection happens pre- and perioperatively, at the 3 months and 1-year follow-up and annually thereafter. Surgery, implant and follow-up case report forms are administered by spinal surgeons. Comorbidity questionnaires, NASS and EQ-5D forms are completed by the patients. Significant and clinically relevant reduction of low back pain VAS (70.3-29.4 points preop to 1-year postop, p < 0.0001) leg pain VAS (55.5-19.1 points preop to 1-year postop, p < 0.001), improvement of quality of life (EQ-5D, 0.32-0.73 points preop to 1-year postop, p < 0.001) and reduction of pain killer consumption was revealed at the 1-year follow-up. There were 14 (3.9%) complications and 7 (2.0%) revisions within the same hospitalization reported for monosegmental TDA; there were 6 (8.6%) complications and 8 (11.4%) revisions for bisegmental surgery. There were 35 patients (9.8%) with complications during followup in monosegmental and 9 (12.9%) in bisegmental surgery and 11 (3.1%) revisions with 1 [corrected] new hospitalization in monosegmental and 1 (1.4%) in bisegmental surgery. Regression analysis suggested a preoperative VAS "threshold value" of about 44 points for increased likelihood of a minimum clinically relevant back pain improvement. In a short-term perspective, lumbar TDA appears as a relatively safe and efficient procedure concerning pain reduction and improvement of quality of life. Nevertheless, no prediction about the long-term goals of TDA can be made yet. The SWISSspine registry proofs to be an excellent tool for collection of observational data in a nationwide framework whereby advantages and deficits of its design must be considered. It can act as a model for similar projects in other health-care domains.

Comparison of pain-resilient working individuals to population-based case controls with/without momentary low back pain

Background: Few studies have examined the 20% of individuals who never experience an episode of low back pain (LBP). To date, no investigation has been undertaken that examines a group who claim to have never experienced LBP in their lifetime in comparison to two population-based case–control groups with and without momentary LBP. This study investigates whether LBP-resilient workers between 50 and 65 years had better general health, demonstrated more positive health behaviour and were better able to achieve routine activities compared with both case–control groups. Methods: Forty-two LBP-resilient participants completed the same pain assessment questionnaire as a population-based LBP sample from a nationwide, large-scale cross-sectional survey in Switzerland. The LBP-resilient participants were pairwise compared to the propensity score-matched case controls by exploring differences in demographic and work characteristics, and by calculating odds ratios (ORs) and effect sizes. A discriminant analysis explored group differences, while the multiple logistic regression analysis specified single indicators which accounted for group differences. Results: LBP-resilient participants were healthier than the case controls with momentary LBP and achieved routine activities more easily. Compared to controls without momentary LBP, LBP-resilient participants had a higher vitality, a lower workload, a healthier attitude towards health and behaved more healthily by drinking less alcohol. Conclusions: By demonstrating a difference between LBP-resilient participants and controls without momentary LBP, the question that arises is what additional knowledge can be attained. Three underlying traits seem to be relevant about LBP-resilient participants: personality, favourable work conditions and subjective attitudes/attributions towards health. These rationales have to be considered with respect to LBP prevention.

Image-based biomechanical assessment of vertebral body and intervertebral disc in the human lumbar spine

Life expectancy continuously increases but our society faces age-related conditions. Among musculoskeletal diseases, osteoporosis associated with risk of vertebral fracture and degenerative intervertebral disc (IVD) are painful pathologies responsible for tremendous healthcare costs. Hence, reliable diagnostic tools are necessary to plan a treatment or follow up its efficacy. Yet, radiographic and MRI techniques, respectively clinical standards for evaluation of bone strength and IVD degeneration, are unspecific and not objective. Increasingly used in biomedical engineering, CT-based finite element (FE) models constitute the state-of-art for vertebral strength prediction. However, as non-invasive biomechanical evaluation and personalised FE models of the IVD are not available, rigid boundary conditions (BCs) are applied on the FE models to avoid uncertainties of disc degeneration that might bias the predictions. Moreover, considering the impact of low back pain, the biomechanical status of the IVD is needed as a criterion for early disc degeneration. Thus, the first FE study focuses on two rigid BCs applied on the vertebral bodies during compression test of cadaver vertebral bodies, vertebral sections and PMMA embedding. The second FE study highlights the large influence of the intervertebral disc’s compliance on the vertebral strength, damage distribution and its initiation. The third study introduces a new protocol for normalisation of the IVD stiffness in compression, torsion and bending using MRI-based data to account for its morphology. In the last study, a new criterion (Otsu threshold) for disc degeneration based on quantitative MRI data (axial T2 map) is proposed. The results show that vertebral strength and damage distribution computed with rigid BCs are identical. Yet, large discrepancies in strength and damage localisation were observed when the vertebral bodies were loaded via IVDs. The normalisation protocol attenuated the effect of geometry on the IVD stiffnesses without complete suppression. Finally, the Otsu threshold computed in the posterior part of annulus fibrosus was related to the disc biomechanics and meet objectivity and simplicity required for a clinical application. In conclusion, the stiffness normalisation protocol necessary for consistent IVD comparisons and the relation found between degeneration, mechanical response of the IVD and Otsu threshold lead the way for non-invasive evaluation biomechanical status of the IVD. As the FE prediction of vertebral strength is largely influenced by the IVD conditions, this data could also improve the future FE models of osteoporotic vertebra.

Consensus on the Need for a Hierarchical List of Patient-reported Pain Outcomes for Metaanalyses of Knee Osteoarthritis Trials: An OMERACT Objective.

OBJECTIVE Although protocol registration for systematic reviews is still not mandatory, reviewers should be strongly encouraged to register the protocol to identify the methodological approach, including all outcomes of interest. This will minimize the likelihood of biased decisions in reviews, such as selective outcome reporting. A group of international experts convened to address issues regarding the need to develop hierarchical lists of outcome measurement instruments for a particular outcome for metaanalyses. METHODS Multiple outcome measurement instruments exist to measure the same outcome. Metaanalysis of knee osteoarthritis (OA) trials, and the assessment of pain as an outcome, was used as an exemplar to assess how Outcome Measures in Rheumatology (OMERACT), the Cochrane Collaboration, and other international initiatives might contribute in this area. The meeting began with formal presentations of background topics, empirical evidence from the literature, and a brief introduction to 2 existing hierarchical lists of pain outcome measurement instruments recommended for metaanalyses of knee OA trials. RESULTS After discussions, most participants agreed that there is a need to develop a methodology for generation of hierarchical lists of outcome measurement instruments to guide metaanalyses. Tools that could be used to steer development of such a prioritized list are the COSMIN checklist (Consensus-based Standards for the selection of health status Measurement Instruments) and the OMERACT Filter 2.0. CONCLUSION We list meta-epidemiological research agenda items that address the frequency of reported outcomes in trials, as well as methodologies to assess the best measurement properties (i.e., truth, discrimination, and feasibility).

Assessment of Intrathecal Pressure in Chondrodystrophic Dogs With Acute Thoracolumbar Disk Disease

OBJECTIVES To assess intrathecal pressure (ITP) in chondrodystrophic dogs with thoracolumbar disk extrusion. STUDY DESIGN Prospective cohort study. ANIMALS Group 1: 11 chondrodystrophic dogs with thoracolumbar disk extrusion and present deep pain sensation. Group 2 (control): 3 healthy chondrodystrophic laboratory dogs without spinal disease. METHODS Diagnosis was based on neurologic signs, magnetic resonance imaging (MRI) findings, and surgical confirmation. Blood pressure was maintained within physiologic range during anesthesia. A standardized surgical procedure was applied to minimize factors that could influence measurement readings. An extended hemilaminectomy was performed and ITP was measured with a fiber optic catheter. The catheter was inserted in the subarachnoid space 1 spinal segment caudal to the level of herniation and its tip was advanced to the site of compression. RESULTS Significantly higher ITP occurred in chondrodystrophic dogs with acute thoracolumbar disk disease compared with controls. ITP was not associated with duration of clinical signs, neurologic status, outcome, degree of spinal cord compression, or signal intensity changes as assessed by MRI. CONCLUSION Acute thoracolumbar disk disease leads to elevated ITP in chondrodystrophic dogs, which may contribute to increased compression of spinal cord parenchyma.

The potential role of endometrial nerve fibers in the pathogenesis of pain during endometrial biopsy at office hysteroscopy

We aimed to evaluate whether nerve fibers are present in the endometrial layer of patients submitted to office hysteroscopy and their potential contribution to the pathogenesis of pain during that procedure. Through a prospective case-control study performed in tertiary centers for women's health, endometrium samples were collected during operative office hysteroscopy from 198 cycling women who previously underwent laparoscopy and/or magnetic resonance imaging investigation for infertility assessment. Samples were classified according to the degree of the pain patients experienced and scored from values ranging from 0 (absence of discomfort/pain) to 10 (intolerable pain) on a 10-cm visual analog scale (VAS). The presence of nerve fiber markers (S100, NSE, SP, VIP, NPY, NKA, NKB, NKR1, NKR2, and NKR3) in the endometrium was also evaluated by morphologic and immunohistochemical analyses. We found that S-100, NSE, NKR1, NK-A, NK-B, VIP, and NPY, were immunolocalized in samples of endometrium, in significantly (P < .01, for all) higher levels in samples collected from patients with VAS score > 5 (group A) than ≤ 5 (group B) and significantly (P < .0001 for all) positively correlated with VAS levels. A statistically significant (P = .018) higher prevalence of endometriosis and/or adenomyosis was depicted in patients of group A than group B. Data from the present study led us to conclude that nerve fibers are expressed at the level of the functional layer of the endometrium and may contribute to pain generation during office hysteroscopy, mainly in women affected by endometriosis and adenomyosis.