Demonstrating the utility of Instrumented Gait Analysis in the treatment of children with cerebral palsy.

BACKGROUND: Instrumented gait analysis (IGA) has been around for a long time but has never been shown to be useful for improving patient outcomes. In this study we demonstrate the potential utility of IGA by showing that machine learning models are better able to estimate treatment outcomes when they include both IGA and clinical (CLI) features compared to when they include CLI features alone. DESIGN: We carried out a retrospective analysis of data from ambulatory children diagnosed with cerebral palsy who were seen at least twice at our gait analysis center. Individuals underwent a variety of treatments (including no treatment) between sequential gait analyses. We fit Bayesian Additive Regression Tree (BART) models that estimated outcomes for mean stance foot progression to demonstrate the approach. We built two models: one using CLI features only, and one using CLI and IGA features. We then compared the models' performance in detail. We performed similar, but less detailed, analyses for a number of other outcomes. All results were based on independent test data from a 70%/30% training/testing split. RESULTS: The IGA model was more accurate than the CLI model for mean stance-phase foot progression outcomes (RMSEIGA = 11∘, RMSECLI = 13∘) and explained more than 1.5 × as much of the variance (R2IGA = .45, R2CLI = .28). The IGA model outperformed the CLI model for every level of treatment complexity, as measured by number of simultaneous surgeries. The IGA model also exhibited superior performance for estimating outcomes of mean stance-phase knee flexion, mean stance-phase ankle dorsiflexion, maximum swing-phase knee flexion, gait deviation index (GDI), and dimensionless speed. INTERPRETATION: The results show that IGA has the potential to be useful in the treatment planning process for ambulatory children diagnosed with cerebral palsy. We propose that the results of machine learning outcome estimators-including estimates of uncertainty-become the primary IGA tool utilized in the clinical process, complementing the standard medical practice of conducting a through patient history and physical exam, eliciting patient goals, reviewing relevant imaging data, and so on.

Comparison of five different methodologies for evaluating ankle-foot orthosis stiffness.

BACKGROUND: The mechanical properties of an ankle-foot orthosis (AFO) play an important role in the gait mechanics of the end user. However, testing methodologies for evaluating these mechanical properties are not standardized. The purpose of this study was to compare five different evaluation frameworks to assess AFO stiffness. METHOD: The same 13 carbon composite AFOs were tested with five different methods. Four previously reported custom test fixtures (the BRUCE, KST, SMApp, and EMPIRE) rotated an AFO into dorsiflexion about a defined axis in the sagittal plane. The fifth method involved quasi-static deflection of AFOs into dorsiflexion by hanging weights (HW) from the footplate. AFO rotational stiffness was calculated as the linear fit of the AFO resistive torque and angular deflection. Differences between methods were assessed using descriptive statistics and a repeated measures Friedman with post-hoc Bonferroni-Holm adjusted Wilcoxon signed-rank tests. RESULTS: There were significant differences in measured AFO stiffnesses between test methods. Specifically, the BRUCE and HW methods measured lower stiffness than both the EMPIRE and the KST. Stiffnesses measured by the SMApp were not significantly different than any test method. Stiffnesses were lowest in the HW method, where motion was not constrained to a single plane. The median difference in absolute AFO stiffness across methods was 1.03 Nm/deg with a range of [0.40 to 2.35] Nm/deg. The median relative percent difference, measured as the range of measured stiffness from the five methods over the average measured stiffness was 62% [range 13% to 156%]. When the HW method was excluded, the four previously reported test fixtures produced a median difference in absolute AFO stiffness of 0.52 [range 0.38 to 2.17] Nm/deg with a relative percent difference between the methods of 27% [range 13% to 89%]. CONCLUSIONS: This study demonstrates the importance of developing mechanical testing standards, similar to those that exist for lower limb prosthetics. Lacking standardization, differences in methodology can result in large differences in measured stiffness, particularly for different constraints on motion. Non-uniform measurement practices may limit the clinical utility of AFO stiffness as a metric in AFO prescription and future research.

Interobserver reliability of biplanar radiography is unaffected by clinical factors relevant to individuals at risk of pathological lower limb torsion.

BACKGROUND: Assessments of lower limb torsion are ubiquitous in clinical gait analysis practice as pathologic lower limb rotational deformity may contribute to gait abnormalities, anterior knee pain, as well as other debilitating conditions. Understandably, the overall utility of any torsional assessment is dependent on the measurement method's intrinsic accuracy, precision, and robustness to clinical interference factors. Recently, biplanar radiography (BPR) measurements of torsion have been shown to be both accurate and precise, but the robustness of BPR to potential interference factors is unknown. RESEARCH QUESTION: How robust are BPR lower limb torsional assessments to six potential interference factors: amount of torsion, skeletal maturity, radiograph quality, prior osteotomy, presence of implants, and observer training background and experience? METHODS: In this retrospective cohort study, four observers of diverse backgrounds and experience generated digital 3D reconstructions of 44 lower limbs using BPR images obtained during standard of care visits (age range 7-35 years). From each reconstruction, four lower limb torsional parameters were computed: femoral torsion, femorotibial rotation, tibial torsion, and transmalleolar axis equivalent. The mean absolute deviation (MAD) of each torsional parameter - calculated across the four observers - was used as the measure of reliability and tested against all interference factors. RESULTS: Results demonstrated that the average MAD was 2.1 degrees for femoral torsion, 3.0 degrees for transmalleolar axis equivalent, 3.8 degrees for femorotibial rotation, and 4.7 degrees for tibial torsion. None of the six potential interference factors were found to systematically influence BPR reliability across all four torsional parameters. Of the factors found to statistically influence one or more torsional parameter, none affected MAD values to a clinically meaningful extent. SIGNIFICANCE: In addition to being accurate and precise, BPR appears to be robust to several clinical factors relevant to children and young adults with or at risk for pathological lower limb torsion.

A model for understanding the causes and consequences of walking impairments.

Walking is an important skill with positive impacts on health, function, and well-being. Many disorders impair walking and its positive impacts through a variety of complex and interrelated mechanisms. Any attempt to understand walking impairments, or the effects of interventions intended to treat these impairments, must respect this complexity. Therefore, our main objectives in conducting this study were to (1) propose a comprehensive model for quantifying the causes and consequences of walking impairments and (2) demonstrate the potential utility of the model for supporting clinical care and addressing basic scientific questions related to walking. To achieve these goals, we introduced a model, described by a directed acyclic graph, consisting of 10 nodes and 23 primary causal paths. We gave detailed descriptions of each node and path based on domain knowledge. We then demonstrated the model's utility using a large sample of gait data (N = 9504) acquired as part of routine care at a regional referral center. We analyzed five relevant examples that involved many of the model's nodes and paths. We computed causal effect magnitudes as Shapley values and displayed the overall importance of variables (mean absolute Shapley value), the variation of Shapley values with respect to underlying variables, and Shapley values for individual observations (case studies). We showed that the model was plausible, captured some well-known cause-effect relationships, provided new insights into others, and generated novel hypotheses requiring further testing through simulation or experiment. To aid in transparency, reproducibility, and future enhancements we have included an extensively commented Rmarkdown file and a deidentified data set.

Quantifying alignment bias during the fabrication and fitting of ankle-foot orthoses: A single center study.

BACKGROUND: The sagittal plane alignment of ankle-foot orthoses (AFO) and AFO footwear combinations (AFO-FC) has been shown to influence gait outcomes. As such, clinicians often target a particular alignment during the fabricating and fitting of an AFO to maximize outcomes. RESEARCH QUESTION: How does the alignment of an AFO change during the fabrication and fitting process with respect to the intended, benchmark sagittal plane alignment identified by the consulting orthotist? STUDY DESIGN: Prospective METHODS: The assessment of AFO alignment was performed using a convenience sample of 125 custom molded AFOs from 68 individuals fabricated at our center (57 bilateral AFOs, 11 unilateral AFOs). The alignment of each AFO was measured at 5 distinct steps during the fabrication and fitting process using a recently validated method to measure AFO neutral angle using differential inclinometers. RESULTS: Prior to fabrication, the intended, benchmark alignment set by the consulting orthotist was 90 degrees for 92% of AFOs, was between 1 and 7 degrees of dorsiflexion for 7% of AFOs and was 5 degrees of plantarflexion for 1% of AFOs. Repeated measures ANOVA showed that AFO alignment changed between all fabrication and fitting steps. Overall, paired t-tests confirmed that AFO alignment was consistently 2-5 degrees more dorsiflexed than the benchmark alignment. Prior to fitting shoes, 55% of fabricated AFOs measured more than 2 degrees from the benchmark alignment. After fitting shoes, nearly 87% of AFO-FCs were more than 2 degrees from the benchmark alignment. SIGNIFICANCE: The finding of systematic dorsiflexion bias and changes in AFO alignment throughout the fabrication and fitting process indicates the need to improve AFO fabrication precision. The neutral angle measurement methodology - using differential inclinometers - provides a means to improve this precision by enabling orthotists to precisely quantify and make appropriate adjustments to AFO alignment throughout the entire fabrication and fitting process.

Short-term causal effects of common treatments in ambulatory children and young adults with cerebral palsy: three machine learning estimates.

Orthopedic and neurological impairments (e.g., muscle contractures, spasticity) are often treated in children and young adults with cerebral palsy (CP). Due to challenges arising from combinatorics, research funding priorities, and medical practicalities, and despite extensive study, the evidence base is weak. Our goal was to estimate the short-term effectiveness of 13 common orthopedic and neurological treatments at four different levels of outcome in children and young adults diagnosed with CP. The outcome levels considered were body structures, specific gait kinematic deviations, overall gait kinematic deviations, and functional mobility. We used three well-establish causal inference approaches (direct matching, virtual twins, and Bayesian causal forests) and a large clinical gait analysis database to estimate the average treatment effect on the treated (ATT). We then examined the effectiveness across treatments, methods, and outcome levels. The dataset consisted of 2851 limbs from 933 individuals (some individuals underwent multiple treatment episodes). Current treatments have medium effects on body structures, but modest to minimal effects on gait and functional mobility. The median ATT of 13 common treatments in children and young adults with CP, measured as Cohen's D, bordered on medium at the body structures level (median [IQR] = 0.42 [0.05, 0.60]) and became smaller as we moved along the causal chain through specific kinematic deviations (0.21 [0.01, 0.33]), overall kinematic deviations (0.09 [0.03, 0.19]), and functional mobility (-0.01 [-0.06, 0.13]). Further work is needed to understand the source of heterogeneous treatment effects, which are large in this patient population. Replication or refutation of these findings by other centers will be valuable to establish the generalizability of these results and for benchmarking of best practices.

Validation of the Brazilian Portuguese version of the University of California San Diego Shortness of Breath Questionnaire in patients with interstitial lung disease.

OBJECTIVE: To investigate the reliability, internal consistency and validity of the Brazilian Portuguese version of the University of California San Diego Shortness of Breath Questionnaire (UCSD SOBQ) in patients with interstitial lung disease (ILD). METHODS: Patients with ILD completed the questionnaire at three different time points, one week apart, with the assistance of two independent assessors. Intra- and inter-rater reliability were analysed via the intraclass correlation coefficient (ICC). Internal consistency was assessed with the Cronbach's alpha coefficient. For the validity analysis, associations between variables were assessed with Spearman's or Pearson's correlation coefficient. RESULTS: Thirty patients with ILD (idiopathic pulmonary fibrosis, connective tissue disease-associated pulmonary fibrosis, sarcoidosis, asbestosis or non-specific interstitial pneumonia) were included (15 men; mean age, 59 ± 10 years; DLCO: 46 [33-64] % predicted). UCSD SOBQ scores showed excellent agreement and internal consistency in the intra-rater analysis (ICC: 0.93 [0.85-0.97]; Cronbach alpha: 0.95) and in the inter-rater analysis (ICC: 0.95 [0.89-0.97]; Cronbach alpha: 0.95), as well as correlating significantly with dyspnoea (as assessed by the Medical Research Council scale; r = 0.56); Medical Outcomes Study 36-item Short-Form Health Survey domains bodily pain, general health, vitality and physical functioning (-0.40 ≤ r ≤ -0.74); six-minute walk distance (r = -0.38); and quadriceps muscle strength (r = -0.41). CONCLUSIONS: The Brazilian Portuguese version of the UCSD SOBQ is valid, is reliable and has internal consistency in patients with ILD in Brazil.

Alternative methods for measuring ankle-foot orthosis alignment in clinical care.

BACKGROUND: Changes in gait due to an ankle foot orthosis (AFO) have been shown to be impacted by the sagittal plane alignment of the AFO, but there is variability in practice and lack of consensus as to how this alignment should be measured. The neutral angle is a measure of AFO alignment that has the potential to be used by various specialties that prescribe, provide, and analyze AFOs. Currently, a lack of validated measurement methods prevents the neutral angle from being used in various clinical settings. Two experimental neutral angle measurement methods are proposed to address this shortcoming: a portable low-cost method for use during AFO fabrication and fitting, and a laboratory-based method for use during dynamic three-dimensional gait analysis (3DGA). RESEARCH QUESTION: What is the concurrent validity of the two experimental neutral angle measurement methods against the gold standard? METHODS: The gold standard neutral angle measurement (NAGOLD) was prospectively collected during a static 3DGA trial for 19 pediatric AFOs from 10 individuals. While NAGOLD was being collected, the neutral angle was simultaneously measured using digital differential inclinometers (NAINCL). Within the same 3DGA session, the neutral angle was also measured during the swing phase of gait (NASWING). The NAINCL and NASWING measurements were compared to NAGOLD using repeated measures ANOVA, ICC, and bootstrapped errors-in-variables regressions. RESULTS: Repeated measures ANOVA indicated no differences between measurement methods (p = 0.43) and ICC analysis indicated good absolute agreement (ICC(A-1) = 0.85). Mean absolute deviations between the NAINCL and NASWING with NAGOLD measurements were 2.4 ° and 1.9 °, with standard deviations of 2.9 ° and 2.7 °, respectively. Maximum observed differences were less than 7 °. The NAINCL and NASWING methods explained 74 % and 81 % of the variance in NAGOLD, respectively. SIGNIFICANCE: The concurrent validity of two new neutral angle measurement methods provides alternative means to assess AFO alignment in the clinic.

A patella marker to improve hip and knee kinematics for models with functionally defined joint axes.

BACKGROUND: The clinical utility of motion capture modeling relies on the accurate tracking of segment motions. Soft tissue artefact presents a particular challenge for modeling hip rotation, knee rotation, and knee varus-valgus motions. The integration of a patella marker has been shown to significantly improve hip rotation tracking for models that utilize anatomical definitions of joint axes (e.g. anatomical models). However, these modeling improvements have not been extended to models that use functional segment motion to define joint axes (e.g. functional models). RESEARCH QUESTION: How does the positioning of a patella marker influence functional model performance? METHODS: A patella functional model (PFM) was created by integrating a patella marker into the functional model (FM) used at our center. Nine distinct versions of the PFM were created using a 3 × 3 grid of markers placed across the patella. Ten typically developing participants performed controlled hip rotation, controlled knee flexion-extension, and free speed walking trials to assess FM and PFM performance differences. RESULTS: The top performing PFM modeled 98 ± 8 % of the reference hip rotation range of motion compared to 71 ± 9 % for the FM. This PFM had low sensitivity to knee flexion-extension motion, 5 ± 10 %. For walking kinematics, this top performing PFM reported 14 % greater hip rotation ROM during stance, 46 % less knee rotation ROM over the entire gait cycle, and 32 % less knee varus-valgus during swing compared to the FM. The differences in modeling are nearly identical to those reported between skin mounted marker and fluoroscopy-based models, indicating that utilization of the patella marker leads to improvements in tracking accuracy. SIGNIFICANCE: Utilization of a precisely placed patella marker led to substantial improvements in modeled hip rotation, knee rotation, and knee varus-valgus. These improvements have the potential to positively impact those specialties that rely on motion capture modeling for clinical decision-making, such as orthopedic surgery.

Examining the Need to Standardize Implanted Stimulator Connectors: NANS Survey Results.

INTRODUCTION: Connectors between implanted stimulator electrodes and pulse generators allow revisions, including battery changes or generator upgrades, to proceed without disturbing uninvolved components, such as the electrode. As new devices are introduced, however, connector incompatibility, even with updated hardware from the same manufacturer, can lead to additional procedures, expense, and morbidity. MATERIALS AND METHODS: Following the example of the cardiac pacemaker/defibrillator industry, the Institute of Neuromodulation (IoN) met to explore the possibility of creating connector standards for implanted neurostimulation devices. At a subsequent meeting of the Association for the Advancement of Medical Instrumentation, which coordinates the development of such standards, industry representatives asked for data defining the need for a new standard. Accordingly, IoN prepared an online survey to be sent to the North American Neuromodulation Society mailing list regarding experience with the connectivity of spinal cord stimulation (SCS) generators and electrodes. RESULTS: The 87 respondents of 9657 surveyed included 77 clinicians, who reported a total of 42,572 SCS implants and revisions. More than a quarter of revisions (2741 of 9935) required the interconnection of devices made by separate manufacturers, in most cases (n = 1528) to take advantage of a new feature (e.g., rechargeability, new waveform) or because an original component could not be replaced (n = 642). Connector adapters provided by manufacturers were used in less than half (n = 1246) of these cases. Nearly all (94%) of the clinicians agreed that standardized connectors should be developed for SCS, and 86% opined that standardized connectors should be developed for other neurostimulation therapies. CONCLUSION: Those who responded to our survey support the development of standard connectors for implanted stimulators, with voluntary compliance by manufacturers, to mitigate the need for adapters and facilitate interchanging components when appropriate. Other advantages to patients and manufacturers might accrue from the adoption of standards, as technology evolves and diversifies.

Rectus femoris transfer in children with cerebral palsy: comparing a propensity score-matched observational study to a randomized controlled trial.

AIM: To test whether an observational study employing propensity score matching could accurately estimate the causal treatment effects of rectus femoris transfer (RFT) as part of single-event multilevel surgery (SEMLS) in ambulatory children with cerebral palsy. METHOD: We used a large clinical database to derive a propensity score for treatment assignment (SEMLS±RFT) and used this score to generate a matched patient cohort. We compared the causal treatment effects estimated from this matched cohort with a previously published randomized controlled trial (RCT). RESULTS: The treated arms of the observational study and RCT were well matched. There were 129 limbs (81 males) with a mean age of 10 years 7 months (4y 7mo) in the treated arm of the observational study, and 129 limbs (68 males) with a mean age of 10 years 2 months (3y 9mo) in the control arm of the observational study. Differences between the observational study and RCT cohorts were clinically meaningless for knee flexion kinematics (1-4°), timing of knee angle extrema (<3% gait cycle), and speed (<5mm/s). Postoperative changes in the observational study matched those from the RCT. All but one of the observational study confidence intervals were completely contained within the corresponding RCT confidence interval; there were no meaningful differences in magnitude or sign of key outcomes related to stiff knee gait. INTERPRETATION: Propensity score matching is an accurate method for estimating the causal treatment effects of RFT as part of an SEMLS. It seems reasonable to extend this approach to other common components of SEMLS treatment in this population. WHAT THIS PAPER ADDS: Propensity score matching is an accurate method for estimating the causal treatment effects of rectus femoris transfer (RFT) in ambulatory children with cerebral palsy (CP). The causal treatment effects for RFT surgery in ambulatory children diagnosed with CP were validated.

Reliability of the modified lateral pillar classification for Legg Calvé Perthes disease performed by a large group of international paediatric orthopaedic surgeons.

PURPOSE: The modified lateral pillar classification (mLPC) is used for prognostication in the fragmentation stage of Legg Calvé Perthes disease. Previous reliability assessments of mLPC range from fair to good agreement when evaluated by a small number of observers with pre-selected radiographs. The purpose of this study was to determine the inter-observer and intra-observer reliability of mLPC performed by a group of international paediatric orthopaedic surgeons. Surgeons self-selected the radiograph for mLPC assessment, as would be done clinically. METHODS: In total, 40 Perthes cases with serial radiographs were selected. For each case, 26 surgeons independently selected a radiograph and assigned mLPC and 21 raters re-evaluated the same 40 cases to establish intra-observer reliability. Rater performance was determined through surgeon consensus using the mode mLPC as 'gold standard'. Inter-observer and intra-observer reliability data were analysed using weighted kappa statistics. RESULTS: The weighted kappa for inter-observer correlation for mLPC was 0.64 (95% confidence interval: 0.55 to 0.74) and was 0.82 (range: 0.35 to 0.99) for intra-observer correlation. Individual surgeon's overall performance varied from 48% to 88% agreement. Surgeon mLPC performance was not influenced by years of experience (p = 0.51). Radiograph selection did not influence gold standard assignment of mLPC. There was greater agreement on cases of mild B hips and severe C hips. CONCLUSIONS: mLPC has low good inter-observer agreement when performed by a large number of surgeons with varied experience. Surgeons frequently chose different radiographs, with no impact on mLPC agreement. Further refinement is needed to help differentiate hips on the border of group B and C. LEVEL OF EVIDENCE: III.

Thinking inside the box: Custom pacemaker improves device longevity in a congenital heart patient.

Patients with congenital heart disease have unique pacing challenges and often require epicardial systems. High pacing threshold is one of the major factors that decrease these systems' durability. Sometimes surgical reintervention or lead replacement is difficult or prohibitive in these patients due to repeated surgeries and extensive epicardial scar. We present a case report of a patient with Fontan physiology and chronically high epicardial lead pacing thresholds requiring frequent generator changes and a unique solution focusing on improving generator longevity.

Medical Director Responsibilities for Outpatient Pulmonary Rehabilitation Programs in the United States: 2019: A STATEMENT FOR HEALTH CARE PROFESSIONALS FROM THE AMERICAN ASSOCIATION OF CARDIOVASCULAR AND PULMONARY REHABILITATION (AACVPR).

Clinical guidelines have been developed recognizing pulmonary rehabilitation (PR) as a key component in the management of patients with chronic lung disease. The medical director of a PR program is a key player in every program and is a requirement for operation of the program. The medical director must be a licensed physician who has experience in respiratory physiology management. The purpose of this document is to provide an update regarding the clinical, programmatic, legislative, and regulatory issues that impact PR medical directors in North America. It describes the clinical rationale for physician involvement, relevant legislative and regulatory requirements, and resources available that the medical director can utilize to promote evidence-based and cost-effective PR services. All pulmonary rehabilitation (PR) programs must include a medical director. There are many clinical, programmatic, legislative, and regulatory issues that impact the PR medical director. The purpose of this document is to concentrate on the unique roles and responsibilities of the PR medical director.

Effects of curative-intent lung cancer therapy on functional exercise capacity and patient-reported outcomes.

PURPOSE: Lung cancer treatment can lead to negative health consequences. We analyzed the effects of curative-intent lung cancer treatment on functional exercise capacity (EC) and patient-reported outcomes (PROs). METHODS: We performed a prospective, observational cohort study of consecutive patients with stage I-IIIA lung cancer undergoing curative-intent therapy and assessed functional EC (primary outcome, six-minute walk distance (6MWD)), cancer-specific quality of life (QoL) (secondary outcome, European Organization for Research and Treatment of Cancer QoL Questionnaire Core 30 (EORTC-QLQ-C30) summary score), and exploratory outcomes including dyspnea (University of California San Diego Shortness of Breath Questionnaire (UCSD SOBQ)) and fatigue Brief Fatigue Inventory (BFI)) symptoms before and at 1 to 3 months post-treatment. We analyzed the time effect of treatment on outcomes using multivariable generalized estimating equations. RESULTS: In 35 enrolled participants, treatment was associated with a clinically meaningful and borderline-significant decline in functional EC ((mean change, 95% CI) 6MWD = - 25.4 m (- 55.3, + 4.47), p = 0.10), clinically meaningful and statistically significant higher dyspnea (UCSD SOBQ = + 13.1 (+ 5.7, + 20.6), p = 0.001) and fatigue (BFI = + 10.0 (+ 2.9, + 17.0), p = 0.006), but no clinically meaningful or statistically significant change in cancer-specific QoL (EORTC-QLQ-C30 summary score = - 3.4 (- 9.8, + 3.0), p = 0.30). CONCLUSIONS: Among the first prospective analysis of the effect of curative-intent lung cancer treatment on functional EC and PROs, we observed worsening dyspnea and fatigue, and possibly a decline in functional EC but not cancer-specific QoL at 1 to 3 months post-treatment. Interventions to reduce treatment-related morbidities and improve lung cancer survivorship may need to focus on reducing dyspnea, fatigue, and/or improving functional EC.

A Model-Based Cost-Effectiveness Analysis of an Exercise Program for Lung Cancer Survivors After Curative-Intent Treatment.

OBJECTIVE: The cost-effectiveness of exercise interventions in lung cancer survivors is unknown. We performed a model-based cost-effectiveness analysis of an exercise intervention in lung cancer survivors. DESIGN: We used Markov modeling to simulate the impact of the Lifestyle Interventions and Independence for Elders exercise intervention compared with usual care for stage I-IIIA lung cancer survivors after curative-intent treatment. We calculated and considered incremental cost-effectiveness ratios of less than US $100,000/quality-adjusted life-year as cost-effective and assessed model uncertainty using sensitivity analyses. RESULTS: The base-case model showed that the Lifestyle Interventions and Independence for Elders exercise program would increase overall cost by US $4740 and effectiveness by 0.06 quality-adjusted life-years compared with usual care and have an incremental cost-effectiveness ratio of US $79,504/quality-adjusted life-year. The model was most sensitive to the cost of the exercise program, probability of increasing exercise, and utility benefit related to exercise. At a willingness-to-pay threshold of US $100,000/quality-adjusted life-year, Lifestyle Interventions and Independence for Elders had a 71% probability of being cost-effective compared with 27% for usual care. When we included opportunity costs, Lifestyle Interventions and Independence for Elders had an incremental cost-effectiveness ratio of US $179,774/quality-adjusted life-year, exceeding the cost-effectiveness threshold. CONCLUSIONS: A simulation of the Lifestyle Interventions and Independence for Elders exercise intervention in lung cancer survivors demonstrates cost-effectiveness from an organization but not societal perspective. A similar exercise program for lung cancer survivors may be cost-effective.

Characterization of Dyspnea in Veteran Lung Cancer Survivors Following Curative-Intent Therapy.

PURPOSE: Dyspnea is highly prevalent in lung cancer survivors following curative-intent therapy. We aimed to identify clinical predictors or determinants of dyspnea and characterize its relationship with functional exercise capacity (EC). METHODS: In an analysis of data from a cross-sectional study of lung cancer survivors at the VA San Diego Healthcare System who completed curative-intent therapy for stage I-IIIA disease ≥1 mo previously, we tested a thorough list of comorbidities, lung function, and lung cancer characteristics. We assessed dyspnea using the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire Lung Cancer Module 13 (LC13) and functional EC using the 6-minute walk. We replicated results with the University of California San Diego Shortness of Breath Questionnaire. RESULTS: In 75 participants at a median of 12 mo since treatment completion, the mean ± SD LC13-Dyspnea score was 35.3 ± 26.2; 60% had abnormally high dyspnea. In multivariable linear regression analyses, significant clinical predictors or determinants of dyspnea were (ß [95% CI]) psychiatric illness (-20.8 [-32.4 to -9.09]), heart failure with reduced ejection fraction (-15.5 [-28.0 to -2.97]), and forced expiratory volume in the first second of expiration (-0.28 [-0.49 to -0.06]). Dyspnea was an independent predictor of functional EC (-1.54 [-2.43 to -0.64]). These results were similar with the University of California San Diego Shortness of Breath Questionnaire. CONCLUSION: We identified clinical predictors or determinants of dyspnea that have pathophysiological bases. Dyspnea was independently associated with functional EC. These results have implications in efforts to reduce dyspnea and improve exercise behavior and functional EC in lung cancer survivors following curative-intent therapy.

Heart rate variability and heart rate recovery in lung cancer survivors eligible for long-term cure.

Lung cancer survivors are at risk for physical fitness and autonomic function impairments. In a cross-sectional study of consecutive lung cancer survivors post-curative intent therapy, we assessed and identified predictors of resting heart rate variability (HRV) and heart rate recovery (HRR), defined as standard deviation of normal-to-normal-R-to-R intervals (SDNN) and root-mean-square-of-successive-differences (rMSSD) from routine outpatient single 10-s electrocardiographs (ECGs) and difference in heart rate (HR) at 1-minute following and the end of the six-minute-walk-test (6MWT), respectively. In 69 participants, the mean (SD) HRR was -10.6 (6.7) beats. Significant independent predictors of HRR were age and HR change associated with the 6MWT. In a subset of 41 participants with available ECGs, the mean (SD) SDNN and rMSSD were 19.1 (15.6) and rMSSD 18.2 (14.6) ms, respectively. Significant independent predictors of HRV were supine HR, HRR, and total lung capacity. HRV/HRR may be useful physiological measures in studies aimed at improving physical fitness and/or autonomic function in lung cancer survivors.

Interobserver reliability in the interpretation of three-dimensional gait analysis in children with gait disorders.

AIM: To assess interobserver reliability in the interpretation of three-dimensional gait analysis (3DGA) of children with gait disorders within a single institution. METHOD: Seven experienced interpreters in our institution participated in a quality-assurance program reviewing one unique patient's 3DGA data every 3 months. Between 2014 and 2017, 15 patients' data were interpreted (14 with spastic cerebral palsy, 1 with myelodysplasia). Interpreters were asked to select 'yes', 'no', or 'indeterminate' from a list of problems and treatment recommendations. Kappa and percent agreement calculations were performed to evaluate consistency. RESULTS: Average percentage agreement in problem identification and treatment recommendation was greater than 84 percent and 90 percent for all interpreters respectively. Average kappa for the 10 most consistently identified problems and recommended treatments were 0.69 and 0.59 respectively. Interpreter consistency was moderate or better for the most commonly performed operations at our institution (0.44-0.59). Sagittal plane abnormalities of the hip and knee had the highest consistency. INTERPRETATION: When institutional differences in data collection and regional variations in management philosophies are removed, interobserver consistency in 3DGA interpretation is moderate to substantial for many commonly selected items. Identification of areas with poor consistency may help address underlying causes and improve data processes. WHAT THIS PAPER ADDS: Consistency in three-dimensional gait analysis interpretation and treatment recommendation is high within a single institution. There is moderate or better consistency for most commonly identified problems and recommended treatments. Sagittal plane problem identification of the hip and knee have the highest consistency. Lower consistency is seen in areas with poor objective measures, such as dystonia and balance.

FIABILIDAD INTEREVALUADOR EN LA INTERPRETACIÓN DEL ANÁLISIS TRIDIMENSIONAL DE LA MARCHA EN NIÑOS CON TRASTORNOS DE LA MARCHA: OBJETIVO: Evaluar la fiabilidad interevaluador en la interpretación del análisis tridimensional de la marcha de niños con trastornos de la marcha, pertenecientes a una institución. MÉTODO: Siete evaluadores de la institución con experiencia participaron en un programa de aseguramiento de calidad, revisando los datos del análisis tridimensional de la marcha de un único paciente cada 3 meses. Entre 2014 y 2017, se interpretaron los datos de 15 pacientes (14 con parálisis cerebral espástica, 1 con mielodisplasia). Se solicitó a los intérpretes seleccionar "sí", "no", o "indeterminado" frente a una lista de problemas y recomendaciones de tratamiento. Se calculó el coeficiente de Kappa y el porcentaje de acuerdo, para evaluar la consistencia. RESULTADOS: El porcentaje de acuerdo promedio en la identificación de problemas y recomendaciones de tratamiento fue mayor que 8% y 90% para todos los intérpretes, respectivamente. El coeficiente de Kappa promedio para los 10 problemas y recomendaciones de tratamiento más identificados fue 0,69 y 0,59, respectivamente. La consistencia de intérpretes fue moderada o mejor para las operaciones más frecuentemente realizadas en nuestra institución (0,44-0,59). Los defectos en el plano sagital de la cadera y rodilla tuvieron la mayor consistencia. INTERPRETACIÓN: Cuando se elimina las diferencias en la recolección de datos y en las variaciones regionales de filosofías de manejo, la consistencia interobservador en la interpretación del análisis tridimensional de la marcha es moderada a buena, para las categorías seleccionadas más frecuentes. La identificación de áreas con baja consistencia podría ayudar a abordar causas subyacentes y mejorar el procesamiento de los datos.

CONFIABILIDADE INTER-EXAMINADORES NA INTERPRETAÇÃO DE ANÁLISE TRIDIMENSIONAL DA MARCHA EM CRIANÇAS COM DESORDENS DA MARCHA: OBJETIVO: Avaliar a confiabilidade inter-examinadores na interpretação de análise tridimensional da marcha (A3DM) em crianças com desordens de marcha de um único instituto. MÉTODO: Sete intérpretes experientes de nossa instituição participaram de um programa de avaliação de qualidade revisando os dados de A3DM de um único paciente a cada 3 meses. Entre 2014 e 2017, os dados de 15 pacientes foram intepretados (14 com paralisia cerebral espástica, 1 com mielodisplasia). Os intérpretes foram solicitados a selecionar "sim", "não", ou "indeterminado" a partir de uma lista de problemas e recomendações de tratamento. Cálculos de concordância kappa e porcentagens foram realizados para avaliar a consistência. RESULTADOS: A porcentagem média de concordância na identificação de um problema e recomendação de tratamento foi maior do que 84% e 90% para todos os intérpretes, respectivamente. O kappa médio para os 10 problemas mais consistentemente identificados e tratamentos mais recomendados foi 0,69 e 0,59, respectivamente. A consistência dos intérpretes foi moderada ou melhor para as operações mais comumente realizadas em nossa instituição (0,44-0,59). Anormalidades no plano sagital do quadril e joelho tiveram a maior consistência. INTERPRETAÇÃO: Quando diferenças institucionais na coleta de dados, e variações regionais em filosofias de manejo são removidas, a consistência inter-examinadores da interpretação da A3DM é de moderada a substancial para muitos dos itens comumente selecionados. A identificação de áreas com pobre consistência pode ajudar a abordar causas e melhorar processos de dados.