Development and temporal validation of clinical prediction models for 1-year disability and pain after lumbar decompressive surgery. The Norwich Lumbar Surgery Predictor (development version).

PURPOSE: To identify clinical predictors and build prediction models for 1-year patient-reported outcomes measures (PROMs) after lumbar decompressive surgery for disc herniation or spinal stenosis. METHODS: The study included 1835 cases, with or without additional single-level fusion, from a single centre from 2008 through 2020. General linear models imputed with 37 clinical variables identified 18 significant 1-year PROM predictors for retention in development models. Interaction of surgical indication with each predictor was tested. Temporal validation was conducted at the same centre on cases through 2021. R2 was used to measure goodness-of-fit, and area under curve (AUC) used to measure classification to a satisfactory symptom state (Oswestry Disability Index (ODI) ≤ 22; back or leg pain ≤ 30 out of 100). RESULTS: A total 1228 (67%) had complete data for inclusion in model development. Predictors of ODI were baseline PROMs (ODI, back pain, leg pain), work status, condition duration, previous lumbar operation, multiple-joint osteoarthritis, female, diabetes, current smoker, rheumatic disorder, lower limb arthroplasty, mobility aided, provider status, facet cyst, scoliosis, and age, with BMI significantly associated with stenosis. Temporal validation (n = 188) found the ODI model R2 was 0.29 (95% confidence intervals (CI) 0.18-0.40) and AUC was 0.74 (95% CI 0.67-0.81). Back and leg pain models had lower R2 (0.12-0.14) and AUC (0.68-0.69) values. CONCLUSION: Important PROM predictors are baseline PROMs, specific co-morbidities, work status, condition duration, previous lumbar operation, female, and smoking status. The ODI model predicted the likelihood of achieving a satisfactory state of both disability and pain.

Incidence and risk factors for five-year recurrent disc herniation after primary single-level lumbar discectomy.

To identify the incidence and risk factors for five-year same-site recurrent disc herniation (sRDH) after primary single-level lumbar discectomy. Secondary outcome was the incidence and risk factors for five-year sRDH reoperation. A retrospective study was conducted using prospectively collected data and patient-reported outcome measures, including the Oswestry Disability Index (ODI), between 2008 and 2019. Postoperative sRDH was identified from clinical notes and the centre's MRI database, with all imaging providers in the region checked for missing events. The Kaplan-Meier method was used to calculate five-year sRDH incidence. Cox proportional hazards model was used to identify independent variables predictive of sRDH, with any variable not significant at the p < 0.1 level removed. Hazard ratios (HRs) were calculated with 95% confidence intervals (CIs). Complete baseline data capture was available for 733 of 754 (97.2%) consecutive patients. Median follow-up time for censored patients was 2.2 years (interquartile range (IQR) 1.0 to 5.0). sRDH occurred in 63 patients at a median 0.8 years (IQR 0.5 to 1.7) after surgery. The five-year Kaplan-Meier estimate for sRDH was 12.1% (95% CI 9.5 to 15.4), sRDH reoperation was 7.5% (95% CI 5.5 to 10.2), and any-procedure reoperation was 14.1% (95% CI 11.1 to 17.5). Current smoker (HR 2.12 (95% CI 1.26 to 3.56)) and higher preoperative ODI (HR 1.02 (95% CI 1.00 to 1.03)) were independent risk factors associated with sRDH. Current smoker (HR 2.15 (95% CI 1.12 to 4.09)) was an independent risk factor for sRDH reoperation. This is one of the largest series to date which has identified current smoker and higher preoperative disability as independent risk factors for sRDH. Current smoker was an independent risk factor for sRDH reoperation. These findings are important for spinal surgeons and rehabilitation specialists in risk assessment, consenting patients, and perioperative management.

Instantaneous VO2 from a wearable device.

We present a method for calculating instantaneous oxygen uptake (VO2) through the use of a non-invasive and non-obtrusive (i.e. without a face mask) wearable device, together with its clinical evaluation against a standard technique based upon expired gas calorimetry. This method can be integrated with existing wearable devices, we implemented it in the "Device for Reliable Energy Expenditure Monitoring" (DREEM). The DREEM comprises a single lead electrocardiogram (ECG) device combined with a tri-axial accelerometer and is worn around the waist. Our clinical evaluation tests the developed method against a gold standard for VO2, expired gas calorimetry, using an ethically approved protocol comprising active exercise and sedentary periods. The study was performed on 42 participants from a wide sample population including healthy people, athletes and an at-risk health group including persons affected by obesity. We developed an algorithm combining heart rate (HR) and the integral of absolute acceleration (IAA), with results showing a correlation of r = 0.93 for instantaneous VO2, and r = 0.97 for 3 min mean VO2, this is a considerably improved estimation of VO2 in comparison to methods utilising HR and IAA independently.

Development of a pictorial scale for assessing functional interference with chronic pain: the Pictorial Pain Interference Questionnaire.

BACKGROUND: Assessment of function and functional interference is an important component of chronic pain assessment and treatment and is commonly based on self-report questionnaires. Existing questionnaires for assessing functional interference are language dependent, which can limit their utility for patients across cultures with literacy, fluency, or cognitive restrictions. OBJECTIVE: The objectives of this study were to create a tool with minimal language dependence and literacy requirement for measuring functional interference due to chronic pain and evaluate the psychometric properties and usability of this new assessment scale, the Pictorial Pain Interference Questionnaire (PPIQ), in a clinical sample of participants with chronic pain. DESIGN: The study employed a prospective, cross-sectional design in a clinical chronic pain setting. PARTICIPANTS AND METHODS: A total of 113 participants with chronic non-cancer pain were recruited from a private chronic pain clinic. A pictorial scale was developed and tested via psychometric procedures, including comparisons with validated measures of functional interference and related chronic pain constructs. RESULTS: Excellent internal consistency reliability (a=0.91), good construct validity (total score: r=0.72-0.81), and adequate-to-good convergent and discriminant validities were demonstrated through comparative analyses with existing self-report questionnaires. A scoring metric for classifying low, moderate, and high levels of interference was found to have good construct validity. Evaluation of satisfaction revealed adequate understanding of the PPIQ among most users. CONCLUSION: Initial support for the PPIQ as an alternative to language-based questionnaires for assessing functional interference from chronic pain was found. Subsequent research will help to clarify psychometric properties of the PPIQ and user response among various chronic pain subgroups.

Correlations between watershed and reservoir characteristics, and algal blooms in subtropical reservoirs.

This study examined the correlations between watershed and reservoir characteristics, and water quality parameters related to algal blooms in seven subtropical reservoirs. Analysis of the dissimilarity of physico-chemical parameters resulted in separation of the reservoirs into three main groups: four reservoirs with the highest proportion of agriculture and/or urban land use in their watersheds; two reservoirs with a high proportion of forest cover; and one small reservoir with a relatively pristine watershed intermediate between the other two groups. All reservoirs were dominated by cyanobacteria, and at times, had species capable of producing toxins. However, the three reservoirs with the lowest percentage forest cover ( approximately 50%) had the highest frequency and magnitude of toxic species, principally Cylindrospermopsis raciborskii. Analysis of dissimilarity of algal species composition resulted in three reservoir groups similar to that for the physico-chemical parameters, with the exception of the reservoir with the highest percentage urban land use being an outlier. Across all reservoirs, percentage forest cover in the watershed, watershed area and reservoir volume were all significantly correlated with algal cell concentrations and total nitrogen (TN), but not with chlorophyll a concentrations. Total phosphorus (TP) was only correlated with the proportion forest cover in the watershed, suggesting that reservoir volume and depth were of less importance for TP than for algal cell concentrations or TN. These results suggest that watershed pattern and reservoir characteristics, such as water volume and depth, have a measurable effect on the type of algal blooms in reservoirs.

The fear-avoidance model of chronic pain: validation and age analysis using structural equation modeling.

The cognitive-behavioral, fear-avoidance (FA) model of chronic pain (Vlaeyen JWS, Kole-Snijders AMJ, Boeren RGB, van Eek H. Fear of movement/(re)injury in chronic low back pain and its relation to behavioral performance. Pain 1995a;62:363-72) has found broad empirical support, but its multivariate, predictive relationships have not been uniformly validated. Applicability of the model across age groups of chronic pain patients has also not been tested. Goals of this study were to validate the predictive relationships of the multivariate FA model using structural equation modeling and to evaluate the factor structure of the Tampa Scale of Kinesiophobia (TSK), levels of pain-related fear, and fit of the FA model across three age groups: young (< or =40), middle-aged (41-54), and older (> or =55) adults. A heterogeneous sample of 469 chronic pain patients provided ratings of catastrophizing, pain-related fear, depression, perceived disability, and pain severity. Using a confirmatory approach, a 2-factor, 13-item structure of the TSK provided the best fit and was invariant across age groups. Older participants were found to have lower TSK fear scores than middle-aged participants for both factors (FA, Harm). A modified version of the Vlaeyen JWS, Kole-Snijders AMJ, Boeren RGB, van Eek H (Fear of movement/(re)injury in chronic low back pain and its relation to behavioral performance. Pain 1995a;62:363-72.) FA model provided a close fit to the data (chi(2)(29)=42.0, p>0.05, GFI=0.98, AGFI=0.97, CFI=0.99, RMSEA=0.031 (90% CI 0.000-0.050), p close fit=0.95). Multigroup analyses revealed significant differences in structural weights for older vs. middle-aged participants. For older chronic pain patients, a stronger mediating role for pain-related fear was supported. Results are consistent with a FA model of chronic pain, while indicating some important age group differences in this model and in levels of pain-related fear. Longitudinal testing of the multivariate model is recommended.

The cognitive risk profile for pain: development of a self-report inventory for identifying beliefs and attitudes that interfere with pain management.

OBJECTIVES: An extensive body of research suggests that maladaptive beliefs about chronic pain can have a negative impact on patient adherence and treatment response. A series of studies to develop and validate a clinically-based, self-report instrument for pain beliefs, the Cognitive Risk Profile for Pain (CRPP), was undertaken. We sought to expand the existing body of knowledge for pain beliefs by development of an instrument with a somewhat different content and format than prior pain belief measures, and a primary focus on clinical risk assessment for treatment planning. METHODS: Test development and evaluation procedures were applied in the initial stages of CRPP development. We report here on a series of studies to evaluate and refine the structure and content of the CRPP, and to establish its internal reliability, concurrent, and criterion validities. A 68-item version of the CRPP was evaluated, including a total risk score and 9 scale scores: philosophic beliefs about pain (PB), denial that mood affects pain (MP), denial that pain affects mood (PM), perception of blame (BL), inadequate support (IS), disability entitlement (DE), desire for medical breakthrough (MB), skepticism of multidisciplinary approach (SM), and conviction of hopelessness (CH). The CRPP was administered to two large samples of chronic pain outpatients (n=499; 125) in conjunction with other self-report scales for pain and associated beliefs, behaviors, and psychopathology. In a final study, treatment outcome measures were obtained for a subsample of chronic pain patients (n=91) to evaluate criterion validity. RESULTS: Confirmatory factor analyses showed improved fit for the CRPP scale structure after elimination of 15 items. The resulting 53-item CRPP was found to have good internal consistency for the full score (alpha=0.82) and 7 of 9 scales, with moderate consistency for scales BL and MB. Low to moderate scale intercorrelations were found. Correlations with pain and psychosocial measures suggested good construct validity for the majority of individual scales and total score. Results were inconsistent for scale MP. Multivariate analyses of variances (MANOVAs) based on tertile split of total risk scores showed significant main effects across pain, mood, productivity, and sleep ratings at 3 and 6-month treatment follow-ups. Analyses of clinically significant treatment changes (ie, 2 points on a 11-point Numerical Rating Scales) showed significantly higher prevalence of treatment "failures" at 6 months among CRPP high-risk patients, but no significant differences at 3 months. DISCUSSION: Results provide initial support for the CRPP as a reliable, valid, and useful measure of general cognitive risk for pain management. Results were supportive of the content and reliabilities of the majority of scale scores. Scales for denial of mood impact on pain, perception of blame, and desire for medical breakthrough will require further evaluation. Data indicate an association of CRPP total risk with multidimensional outcome from medical treatment of chronic pain, supporting relevance to treatment planning. The unique content and format of the CRPP may be useful in some clinical pain settings. Possible applications of the CRPP for risk assessment and treatment planning for chronic pain are discussed.

Native Oxide Transport and Removal During Atomic Layer Deposition of TiO2 Films on GaAs(100) Surfaces.

In this work, we studied the evolution and transport of the native oxides during the atomic layer deposition (ALD) of TiO2 on GaAs(100) from tetrakis dimethyl amino titanium and H2O. Arsenic oxide transport through the TiO2 film and removal during the ALD process was investigated using transmission Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Experiments were designed to decouple these processes by utilizing their temperature dependence. A 4 nm TiO2 layer was initially deposited on a native oxide surface at 100 °C. Ex situ XPS confirmed that this step disturbed the interface minimally. An additional 3 nm TiO2 film was subsequently deposited at 150 to 250 °C with and without an intermediate thermal treatment step at 250 °C. Arsenic and gallium oxide removal was confirmed during this second deposition, leading to the inevitable conclusion that these oxides traversed at least 4 nm of film so as to react with the precursor and its surface reaction/decomposition byproducts. XPS measurements confirmed the relocation of both arsenic and gallium oxides from the interface to the bulk of the TiO2 film under normal processing conditions. These results explain the continuous native oxide removal observed for alkyl-amine precursor-based ALD processes on III-V surfaces and provide further insight into the mechanisms of film growth.

Cervicogenic headache in patients with presumed migraine: missed diagnosis or misdiagnosis?

UNLABELLED: The differential diagnosis of headache is often challenging, with significant clinical and socioeconomic consequences of incomplete or inaccurate diagnosis. Overlapping symptoms contribute to the diagnostic challenge. Four female patients, ages 26 to 69 with standing diagnoses of migraine, were evaluated and treated for complaints of chronic, severe headaches. All had obtained limited relief from migraine therapies. On physical examination, all had occipital nerve tenderness or positive Tinel sign over the occipital nerve. All responded well to occipital nerve blocks with local anesthetic, achieving complete or substantial pain relief lasting up to 2 months. We conclude that accurate diagnosis of occipital neuralgia or cervicogenic headache as contributing factors can lead to substantial headache relief through occipital nerve blocks in patients with coexisting or misdiagnosed migraine. PERSPECTIVE: The pathophysiology of many types of chronic headaches is not well understood. Mixed mechanisms such as neurovascular, neuropathic, myofascial, and cervicogenic may all contribute. Our four patients with chronic headaches responded well to occipital nerve blocks. The neuroanatomical relationship between the trigeminocervical nucleus and occipital nerve may serve as the basis of efficacy for these blocks.

A novel method for non-invasive respiration monitoring.

In this paper we present an atypical method for measuring respiration volume. We infer heart rate variability (HRV) from an electrocardiogram (ECG) and present results from a pilot study of 6 participants to validate measuring respiration volume from HRV in comparison to the Cosmed K4b(2). We show a qualitative correlation and trend between the known respiration volume as measured by the Cosmed K4b(2) and the new method for measuring lung volume. From these results, we propose guidelines for an in-depth study of measuring respiration volumes from heart rate variability.

Considerations for return to work following traumatic brain injury.

Population-based studies have demonstrated that a history positive for traumatic brain injury (TBI) can result in cognitive impairment, behavioral alterations, and pain. These outcomes can and do influence occupational function, can affect others in the workplace, and raise concerns about workplace safety upon re-entry to the workplace. Risk for long-term impairment and disability can in some cases be mitigated by assessment of capabilities relative to job duties, conservative return-to-work schedules, and, in some cases, interventions to support that return. For those in occupations at high risk for brain injury, including first responders, soldiers, and construction workers, the long-term risk of brain injury as a risk factor for neurodegenerative disease must and should inform increased concern for those with repeated injuries to the brain over the course of their lifetime and career. This chapter reviews the risks of TBI, considers factors that optimize functional recovery, and discusses potential interventions and factors that aid in return to the workplace.

Chronic pain acceptance incrementally predicts disability in polytrauma-exposed veterans at baseline and 1-year follow-up.

War veterans are at increased risk for chronic pain and co-occurring neurobehavioral problems, including posttraumatic stress disorder (PTSD), depression, alcohol-related problems, and mild traumatic brain injury (mTBI). Each condition is associated with disability, particularly when co-occurring. Pain acceptance is a strong predictor of lower levels of disability in chronic pain. This study examined whether acceptance of pain predicted current and future disability beyond the effects of these co-occurring conditions in war veterans. Eighty trauma-exposed veterans with chronic pain completed a PTSD diagnostic interview, clinician-administered mTBI screening, and self-report measures of disability, pain acceptance, depression, and alcohol use. Hierarchical regression models showed pain acceptance to be incrementally associated with disability after accounting for symptoms of PTSD, depression, alcohol-related problems, and mTBI (total adjusted R(2) = .57, p < .001, ΔR(2) = .03, p = .02). At 1-year follow-up, the total variance in disability accounted for by the model decreased (total adjusted R(2) = .29, p < .001), whereas the unique contribution of pain acceptance increased (ΔR(2) = .07, p = .008). Pain acceptance remained significantly associated with 1-year disability when pain severity was included in the model. Future research should evaluate treatments that address chronic pain acceptance and co-occurring conditions to promote functional recovery in the context of polytrauma in war veterans.

Electronic pain questionnaires: a randomized, crossover comparison with paper questionnaires for chronic pain assessment.

Electronic questionnaires for pain assessment are becoming increasingly popular. There have been no published reports to establish the equivalence or psychometric properties of common pain questionnaires administered via desktop computers. This study compared responses to paper (P) and touch screen electronic (E) versions of the Short-Form McGill Pain Questionnaire (SF-MPQ) and Pain Disability Index (PDI), while examining the role of computer anxiety and experience, and evaluating patient acceptance. In a randomized, crossover design 189 chronic pain patients completed P and E versions of the SF-MPQ and PDI, and self-ratings of anxiety, experience, relative ease and preference. Psychometric properties were highly similar for P and E questionnaires. For the SF-MPQ, 60% or more of subjects gave equivalent responses on individual descriptors and PPI scale, with 80% rating within +/-1 point for an 11-point VAS. Correlations for the SF-MPQ scales ranged from 0.68 to 0.84. For the PDI, 60% or more of subjects responded within +/-1 point on individual questions, and the total score correlation was 0.67. Comparison of mean difference scores revealed no significant differences between modes for any of the questionnaire items or scores. Anxiety and experience scores showed no significant associations through correlations and high/low comparisons. Although nearly half of subjects reported no computer training, anxiety ratings were low, and considerably more subjects rated the E questionnaires as easier and preferred. Findings are consistent with test-retest reliability data, and support the validity and acceptance of electronic versions of the SF-MPQ and PDI.

Application of the pressure-state-response framework to perceptions reporting of the state of the New Zealand environment.

The Pressure-State-Response framework for environmental reporting was used as a basis to develop a long-term study of people's perceptions of the state of the New Zealand environment. A postal survey of 2000 people, randomly drawn from the New Zealand electoral roll was used to gather data--an effective response rate of 48% was achieved. A range of different resource sectors was examined. We report on New Zealand's air, native animals and plants, and marine fisheries, as well as New Zealand compared to other developed countries. Respondents generally considered that in terms of pressures, states and responses, New Zealand was performing better than other developed countries and that for the resources examined here overall performance was in the adequate to good range, except for marine fisheries. The survey appears to be a useful tool for linking perceptions data into State of the Environment reporting. It also helps identify policy issues where perceptions do not match other scientific evidence or management initiatives. Such findings can be important for the successful implementation of policy measures.