Trevor A. Dyson-Hudson

Pushrim biomechanics and injury prevention in spinal cord injury: Recommendations based on CULP-SCI investigations

Over 50 percent of manual wheelchair users with spinal cord injury (SCI) are likely to develop upper-limb pain and injury. The majority of studies related to pain have implicated wheelchair propulsion as a cause. This paper draws from a large multisite trial and a long-standing research program to make specific recommendations related to wheelchair propulsion that may decrease the risk of upper-limb injury. The studies include over 60 subjects over 1 yr after a traumatic SCI below the second thoracic level. Specific aspects of the propulsive stroke that may relate to injury include cadence, magnitude of force, and the pattern of the hand during the nonpropulsive part of the stroke. Lower peak forces, slower cadence, and a circular propulsive stroke in which the hand falls below the pushrim during recovery may help prevent injury. In addition, wheelchair users should use the lightest weight adjustable wheelchair possible. Future work should include interventional trials and larger studies that allow for more complex statistical models that can further detail the relationship between wheelchair propulsion, user characteristics, and upper-limb injuries.

Shoulder Pain In Chronic Spinal Cord Injury, Part 1: Epidemiology, Etiology, And Pathomechanics

Abstract Study Design: Review of the literature. Background/Objective: Shoulder pain is extremely common in individuals with chronic spinal cord injury (SCI) and is a source of morbidity and fundianal loss. The purpose of this review is to outline the present knowledge of the epidemiology, etiology, and pathomechanics of musculoskeletal shoulder pain inindividuals with chronic SCI. Methods: Review of the Iiterature using PubMed/ MEDLINE, EMBASE, and bibliographies of selected articles. Results: Shoulder pain is more common in individuals with tetraplegia and complete injuries and may occur more frequently in women. Musculoskeletal conditions, primarily injuries to the rotator cuff, are most common. Risk factors include the duration of injury, older age, higher body mass index, the use of a manual wheelchair, poor seated posture, decreased flexibility, and muscle imbalances in the rotator cuff and scapular stabilizing muscles. Conclusion: With a better understanding of the epidemiology, etiology, and basic pathomechanics of shoulder pain in SCI, physicians are in a better position to evaluate, treat, and prevent these disorders.

Dynamometry testing in spinal cord injury

Persons with a spinal cord injury (SCI) demonstrate strength deficits that can limit their functional ability to perform activities of daily living. For a specific lesion level, performance of functional activities is related to the level of muscle strength. Consequently, in clinical practice, we need reliable measures of muscle strength to determine mobility and self-care ability. Muscle-strength testing is used to document recovery or loss of motor function early in SCI, as well as measure improvements in strength in chronic SCI. We also need such measures for research purposes to determine the efficacy of clinical trials. Several methods are available for testing muscle strength of persons with SCI, such as handheld, handgrip, and isokinetic dynamometers. This article provides an overview of muscle-contraction definitions and testing methodologies and discusses the reliability of these testing methods and dynamometry devices.

Cut Point Determination in the Measurement of Pain and Its Relationship to Psychosocial and Functional Measures After Traumatic Spinal Cord Injury: A Retrospective Model Spinal Cord Injury System Analysis

OBJECTIVE To evaluate potential pain cutoff scores reflecting mild, moderate, and severe pain in the spinal cord injury (SCI) population and determine the relationship between the derived cutoff scores and both psychosocial and functional outcome measures. DESIGN Retrospective analysis. SETTING SCI Model Systems. PARTICIPANTS Persons (N=6096; age >18y) with traumatic SCI (American Spinal Injury Association Impairment Scale [AIS] grades A-D; injured in 1973-2008). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Numeric rating scale (NRS) of pain severity (11 points), NRS of pain interference (5 points), Satisfaction With Life Scale, Patient Health Questionnaire-9, Craig Handicap Assessment and Reporting Technique Short-Form (CHART-SF), motor component of the FIM (M-FIM), and employment. RESULTS The best set of pain severity cutoff points are 1 to 3, 4 to 6, and 7 to 10. This was validated by randomly assigning sample members to 2 groups and replicating. There were significant differences in all outcomes as a function of pain severity grouping, although they explained little of the variance in M-FIM and CHART-SF Physical Independence scale scores. Neurologic status differed significantly between pain groups, with incongruence between pain severity and interference in people in the AIS grade D group, who reported the greatest pain interference and least pain severity. CONCLUSION Pain severity can be categorized into groups that reflect pain interference. These groupings differentiate psychosocial well-being better than activity limitations. They do not provide a comprehensive pain assessment, for which pain type, location, and interference are likely to be necessary.

Carpal Tunnel Syndrome in Manual Wheelchair Users with Spinal Cord Injury: A Cross-Sectional Multicenter Study

Yang J, Boninger ML, Leath JD, Fitzgerald SG, Dyson-Hudson TA, Chang MW: Carpal tunnel syndrome in manual wheelchair users with spinal cord injury: A cross-sectional multicenter study. Objective:To investigate relationships between carpal tunnel syndrome, functional status, subject demographics, physical examination findings, and median nerve conduction study findings in manual wheelchair users with paraplegia. Design:Multicenter cross-sectional study. One hundred twenty-six manual wheelchair-using individuals with chronic paraplegia answered self-administered questionnaires on demographics, symptoms, and functional status. They underwent physical examination specific for carpal tunnel syndrome and upper-limb nerve conduction studies. Results:Fifty-seven percent of subjects had symptoms (72.2% bilateral); hand numbness was most common. Sixty percent of subjects had carpal tunnel syndrome physical examination findings (59.2% bilateral). Those with physical examination findings were more likely to have longer duration of injury (P = 0.003). Seventy-eight percent of subjects had electrophysiologic evidence of median mononeuropathy. Symptomatic subjects had significantly greater median-ulnar motor latency difference in the dominant hand (P = 0.02) and smaller compound muscle action potential amplitudes bilaterally (dominant hand, P = 0.01; nondominant hand, P = 0.04). Persons with carpal tunnel syndrome symptoms and physical examination findings had significantly worse functional status (symptoms, P < 0.001; physical examination, P = 0.02) and symptom severity scores (symptoms, P < 0.001; physical examination, P = 0.01), but a similar difference between subjects with and without median mononeuropathy was not seen. Logistic regression analysis revealed that the presence of symptoms was predicted by median-ulnar motor latency difference in the dominant hand (odds ratio, 4.38; 95% confidence interval 1.72–11.14) and sensory nerve action potential amplitude in the nondominant hand (odds ratio, 0.97; 95% confidence interval, 0.94–0.99). Conclusions:The interaction among symptoms, physical examination, and nerve conduction study findings is complex. Carpal tunnel syndrome and median mononeuropathy are highly prevalent and functionally significant. This study highlights the need for primary prevention and patient education for preserving upper-limb function.

Spinal cord injury-functional index: item banks to measure physical functioning in individuals with spinal cord injury.

OBJECTIVES To develop a comprehensive set of patient-reported items to assess multiple aspects of physical functioning relevant to the lives of people with spinal cord injury (SCI), and to evaluate the underlying structure of physical functioning. DESIGN Cross-sectional. SETTING Inpatient and community. PARTICIPANTS Item pools of physical functioning were developed, refined, and field tested in a large sample of individuals (N=855) with traumatic SCI stratified by diagnosis, severity, and time since injury. INTERVENTIONS None. MAIN OUTCOME MEASURE Spinal Cord Injury-Functional Index (SCI-FI) measurement system. RESULTS Confirmatory factor analysis (CFA) indicated that a 5-factor model, including basic mobility, ambulation, wheelchair mobility, self-care, and fine motor function, had the best model fit and was most closely aligned conceptually with feedback received from individuals with SCI and SCI clinicians. When just the items making up basic mobility were tested in CFA, the fit statistics indicated strong support for a unidimensional model. Similar results were demonstrated for each of the other 4 factors, indicating unidimensional models. CONCLUSIONS Though unidimensional or 2-factor (mobility and upper extremity) models of physical functioning make up outcomes measures in the general population, the underlying structure of physical function in SCI is more complex. A 5-factor solution allows for comprehensive assessment of key domain areas of physical functioning. These results informed the structure and development of the SCI-FI measurement system of physical functioning.

Development and initial evaluation of the spinal cord injury-functional index.

OBJECTIVES To describe the calibration of the Spinal Cord Injury-Functional Index (SCI-FI) and report on the initial psychometric evaluation of the SCI-FI scales in each content domain. DESIGN Cross-sectional survey followed by calibration data simulations. SETTING Inpatient and community settings. PARTICIPANTS A sample of participants (N=855) with traumatic spinal cord injury (SCI) recruited from 6 SCI Model Systems and stratified by diagnosis, severity, and time since injury. INTERVENTIONS None. MAIN OUTCOME MEASURE SCI-FI instrument. RESULTS Item response theory analyses confirmed the unidimensionality of 5 SCI-FI scales: basic mobility (54 items), fine motor function (36 items), self-care (90 items), ambulation (39 items), and wheelchair mobility (56 items). All SCI-FI scales revealed strong psychometric properties. High correlations of scores on simulated computer adaptive testing (CAT) with the overall SCI-FI domain scores indicated excellent potential for CAT to accurately characterize functional profiles of adults with SCI. Overall, there was very little loss of measurement reliability or precision using CAT compared with the full item bank; however, there was some loss of reliability and precision at the lower and upper ranges of each scale, corresponding to regions where there were few questions in the item banks. CONCLUSIONS Initial evaluation revealed that the SCI-FI achieved considerable breadth of coverage in each content domain and demonstrated acceptable psychometric properties. The use of CAT to administer the SCI-FI will minimize assessment burden, while allowing for the comprehensive assessment of the functional abilities of adults with SCI.

Evaluation of wheelchair tire rolling resistance using dynamometer- based coast-down tests

The objective of this study was to compare the rolling resistance of four common manual wheelchair tires (two pneumatic and two airless solid) and the solid tires used on a commercially available force- and moment-sensing wheel. Coast-down tests were performed with a wheelchair positioned on a two-drum dynamometer. Within each of three load conditions, tire type had a significant effect on rolling resistance (p < 0.001). The pneumatic tires had smaller rolling resistances and were less affected by load increases than the solid tires. Within the two tire types, higher air pressure or firmness and lower profile tread corresponded to less rolling resistance. Wheelchair users, clinicians, and researchers must consider the effect of tire type on wheelchair rolling resistance when selecting a manual wheelchair tire.

Safety, Tolerance, and Efficacy of Extended-Release Niacin Monotherapy for Treating Dyslipidemia Risks in Persons With Chronic Tetraplegia: A Randomized Multicenter Controlled Trial

OBJECTIVE To test the safety, tolerance, and efficacy of extended-release niacin monotherapy on dyslipidemia in persons with chronic tetraplegia. DESIGN Placebo-controlled, blinded, multicenter, randomized controlled trial. SETTING Three spinal cord injury research/rehabilitation centers. PARTICIPANTS Persons with chronic tetraplegia (N=54) and low plasma high-density lipoprotein cholesterol (HDL-C) levels. INTERVENTION Extended-release niacin monotherapy (48 weeks; n=31) on a dose-titration schedule versus matched placebo (n=23). MAIN OUTCOME MEASURES Safety was assessed by using percentages of treatment-emergent adverse events and increased levels of hepatic transaminases, uric acid, glycosylated hemoglobin, and fasting glucose. Tolerance was assessed by using participant reports for frequency and intensity of adverse effects of extended-release niacin. Primary effectiveness outcomes were fasting HDL-C level and plasma total cholesterol (TC)/HDL-C ratio. Secondary outcomes included plasma low-density lipoprotein cholesterol (LDL-C) and TC levels and LDL-C/HDL-C ratio. RESULTS Significant increases in fasting HDL-C levels (24.5%) were accompanied by decreases in TC/HDL-C and LDL-C/HDL-C ratios, LDL-C levels, and TC levels (all P<.05). No evidence of sustained hepatotoxicity or hyperglycemia was observed. Treatment-emergent withdrawals (12.9%) accompanied flushing (n=1), hypotension/presyncope (n=1), and diarrhea (n=2). One subject experienced transient hyperuricemia. Other drug-reported symptoms did not differ from those for placebo. CONCLUSIONS Extended-release niacin monotherapy is safe, tolerated, and effective for most persons with chronic tetraplegia. Special precautions for changes in bowel habits and postadministration hypotension should be observed.

Establishing a threshold to predict risk of cardiovascular disease from the serum triglyceride and high-density lipoprotein concentrations in persons with spinal cord injury

Study designRetrospective cohort.ObjectiveThis report identified the serum triglyceride (TG) concentrations in persons with spinal cord injury (SCI) and able-bodied (AB) individuals that the serum high-density lipoprotein cholesterol (HDL-C) equaled 40 mg/dl, a concentration below which is an independent risk factor for coronary artery disease.MethodsRetrospective analysis was performed on 578 participants: 223 with SCI at or proximal to the 4th thoracic vertebrae (↑T4), 178 with SCI at or distal to the 5th thoracic vertebrae (↓T5), and 177 AB. Different statistical modeling approaches identified the intersecting serum TG concentration with a serum HDL-C concentration equal to 40 mg/dl. Participants were dichotomized into subgroups by TG concentration exceeding (supra) or falling below (sub) the intersecting value and the TG/HDL-C ratios were compared.ResultsLinear regression analysis revealed that the serum TG concentration that intersects with serum HDL-C concentration at 40 mg/dl was 121 mg/dl in SCI ↑T4 and 137 mg/dl in SCI ↓T5 group. A ROC curve identified the optimal TG concentration as 115 mg/dl in SCI ↑T4 and 137 mg/dl in SCI ↓T5 group with the latter concentration being similar to the AB group (e.g., 137 mg/dl). The TG/HDL-C ratios in the respective ↑T4, ↓T5, and AB supra and subgroups were similar within each group.ConclusionsA lower TG concentration appears to be associated with dyslipidemia in persons with SCI than AB individuals. These findings should prompt clinicians to screen for and consider instituting lifestyle or pharmacological interventions at lower TG concentrations to reduce risk of CVD.