The effect of symptoms of carpal tunnel syndrome on ultrasonographic median nerve measures before and after wheelchair propulsion.

OBJECTIVE: To quantify median nerve characteristics before and after strenuous wheelchair propulsion and relate them to symptoms of carpal tunnel syndrome (CTS). We hypothesized that persons with and without symptoms of CTS would have significantly different nerve characteristics at baseline and after propulsion. DESIGN: A repeated-measures design was used to obtain ultrasound images of the median nerve at 3 levels of the wrist (radius, pisiform, and hamate) before and after wheelchair propulsion. Investigators were blinded to subject history related to CTS. SETTING: The 2007 and 2008 National Veterans Wheelchair Games and the Human Engineering Research Laboratories. PARTICIPANTS: Fifty-four participants between the ages of 18 and 65 years with a nonprogressive disability who used a manual wheelchair as their primary means of mobility completed this study. METHODS: Participants completed questionnaires regarding demographics and the presence and severity of symptoms of CTS. Ultrasound images of the median nerve were obtained before and after a 15-minute strenuous wheelchair-propulsion task. MAIN OUTCOME MEASUREMENTS: Baseline values and post-propulsion changes were determined for median nerve cross-sectional area, flattening ratio, and swelling ratio. Differences in median nerve variables between symptomatic and asymptomatic groups were assessed. RESULTS: No significant differences between symptom groups were identified at baseline; however, persons with symptoms of CTS showed a significantly different percent change from baseline compared with the asymptomatic participants for cross-sectional area at pisiform (P = .014) and flattening ratio at hamate (P = .022), and they showed a strong trend toward a difference in swelling ratio (P = .0502). For each of these variables, the change in the symptomatic group was in the opposite direction of the change in the asymptomatic group. CONCLUSIONS: We found several median nerve responses to wheelchair propulsion associated with symptoms of CTS. These responses occurred even though no baseline ultrasound difference was found based on symptoms. Future research is necessary to determine how propulsion characteristics (ie, force, repetition, and posture) affect the median nerve response.

Effects of computer keyboarding on ultrasonographic measures of the median nerve.

BACKGROUND: Keyboarding is a highly repetitive daily task and has been linked to musculoskeletal disorders of the upper extremity. However, the effect of keyboarding on median nerve injuries is not well understood. The purpose of this study was to use ultrasonographic measurements to determine whether continuous keyboarding can cause acute changes in the median nerve. METHODS: Ultrasound images of the median nerve from 21 volunteers were captured at the levels of the pisiform and distal radius prior to and following a prolonged keyboarding task (i.e., 1 hr of continuous keyboarding). Images were analyzed by a blinded investigator to quantify the median nerve characteristics. Changes in the median nerve ultrasonographic measures as a result of continuous keyboarding task were evaluated. RESULTS: Cross-sectional areas at the pisiform level were significantly larger in both dominant (P = 0.004) and non-dominant (P = 0.001) hands following the keyboarding task. Swelling ratio was significantly greater in the dominant hand (P = 0.020) after 60 min of keyboarding when compared to the baseline measures. Flattening ratios were not significantly different in either hand as a result of keyboarding. CONCLUSION: We were able to detect an acute increase in the area of the median nerve following 1 hr of keyboarding with a computer keyboard. This suggests that keyboarding has an impact on the median nerve. Further studies are required to understand this relationship, which would provide insight into the pathophysiology of median neuropathies such as carpal tunnel syndrome.

Effect of an intense wheelchair propulsion task on quantitative ultrasound of shoulder tendons.

OBJECTIVE: To investigate acute ultrasound changes of biceps and supraspinatus tendon appearance after an intense wheelchair propulsion task, and how these changes relate to demographic and biomechanical risk factors. DESIGN: A survey. SETTING: Research laboratory and research space at the National Veterans Wheelchair Games. PARTICIPANTS: A convenience sample of 60 manual wheelchair users were recruited through research registries and rehabilitation clinics as well as from participants at the 2007 and 2008 National Veterans Wheelchair Games. The subjects were between 18 and 65 years of age at least 1 year after injury and did not have progressive disabilities. MAIN OUTCOME MEASURES: Quantitative ultrasound (QUS) measures of biceps and supraspinatus tendon appearance, stroke frequency, resultant force, tendinopathy score, and duration of wheelchair use. RESULTS: Biceps tendon appearance after an intense propulsion task was significantly related to chronic biceps tendinopathy, duration of wheelchair use, stroke frequency, and resultant force. The subjects with a higher stroke frequency or resultant force tended to have a brighter, more organized tendon appearance compared with the prepropulsion imaging session (baseline). The subjects with tendinopathy or a longer duration of wheelchair use were more likely to have a darker, diffuse tendon appearance immediately after the propulsion task. Supraspinatus tendon appearance after propulsion was only significantly predicted by baseline QUS measures. CONCLUSIONS: QUS has proven to be sensitive to risk factors for tendon pathology. Future studies can apply grayscale-based QUS to study the development and prevention of repetitive strain injuries, particularly on an individual basis.

Repeatability of ultrasonographic median nerve measures.

In this study we investigated the reliability of ultrasound in measuring median nerve characteristics including cross-sectional area (CSA), flattening ratio (FR), swelling ratio (SR), and mean grayscale. Generalizability theory was used to assess inter- and intrarater reliability using the dependability coefficient (phi), normalized standard error of measurement, and normalized minimum detectable change (MDC(NORM)) for multiple study design protocols. Interrater reliability was generally moderate. Intrarater reliability was mostly good (phi > 0.876) when using a single image, captured on one occasion, and being read once. Intrarater MDC(NORM) ranged from 3.8% to 6.2% for all CSA measures and SR. Using multiple images and/or readings at multiple occasions did not appreciably improve reliability measures. Ultrasound is a reliable tool for measuring median nerve characteristics. We recommend that a single evaluator capture all images for protocols aimed at quantifying median nerve ultrasound measures. We believe an appropriately designed protocol can utilize ultrasound to accurately assess changes in median nerve characteristics after activity.

Validation of grayscale-based quantitative ultrasound in manual wheelchair users: relationship to established clinical measures of shoulder pathology.

OBJECTIVE: The primary aim of this study is to establish the validity of grayscale-based quantitative ultrasound (QUS) measures of the biceps and supraspinatus tendons. DESIGN: Nine QUS measures of the biceps and supraspinatus tendons were computed from ultrasound images collected from 67 manual wheelchair users. Shoulder pathology was measured using questionnaires, physical examination maneuvers, and a clinical ultrasound grading scale. RESULTS: Increased age, duration of wheelchair use, and body mass correlated with a darker and more homogenous tendon appearance. Subjects with pain during physical examination tests for biceps tenderness and acromioclavicular joint tenderness exhibited significantly different supraspinatus QUS values. Even when controlling for tendon depth, QUS measures of the biceps tendon differed significantly between subjects with healthy tendons, mild tendinosis, and severe tendinosis. Clinical grading of supraspinatus tendon health was correlated with QUS measures of the supraspinatus tendon. CONCLUSIONS: QUS is valid method to quantify tendinopathy and may allow for early detection of tendinosis. Manual wheelchair users are at a high risk for developing shoulder tendon pathology and may benefit from QUS-based research that focuses on identifying interventions designed to reduce this risk.

Ultrasonographic median nerve changes after a wheelchair sporting event.

OBJECTIVES: To investigate the acute median nerve response to intense wheelchair propulsion by using ultrasonography and to examine the relationship between carpal tunnel syndrome (CTS) signs and symptoms and the acute median nerve response. DESIGN: Case series. SETTING: Research room at the National Veterans Wheelchair Games. PARTICIPANTS: Manual wheelchair users (N=28) competing in wheelchair basketball. INTERVENTION: Ultrasound images collected before and after a wheelchair basketball game. MAIN OUTCOME MEASURES: Median nerve cross-sectional area, flattening ratio, and swelling ratio and changes in these after activity. Comparison of median nerve characteristics and patient characteristics between participants with and without positive physical examination findings and with and without symptoms of CTS. RESULTS: Significant changes in median nerve ultrasound characteristics were noted after activity. The group as a whole showed a significant decrease in cross-sectional area at the radius of 4.05% (P=.023). Participants with positive physical examinations showed significantly different (P=.029) and opposite changes in swelling ratio compared with the normal group. Subjects with CTS symptoms had a significantly (P=.022) greater duration of wheelchair use (17.1 y) compared with the asymptomatic participants (9 y). CONCLUSIONS: Manual wheelchair propulsion induces acute changes in median nerve characteristics that can be visualized by using ultrasound. Studying the acute median nerve response may be useful for optimizing various interventions, such as wheelchair set up or propulsion training, to decrease both acute and chronic median nerve damage and the likelihood of developing CTS.

Reliability of quantitative ultrasound measures of the biceps and supraspinatus tendons.

RATIONALE AND OBJECTIVES: Ultrasound is a proven method for examining soft tissue structures, including tendons, and recently quantitative ultrasound has become more prevalent in research settings. However, limited reliability data have been published for these new quantitative ultrasound measures. The main objective of this study was to quantify the reliability and measurement error of multiple quantitative ultrasound imaging protocols for the biceps and supraspinatus tendons. MATERIALS AND METHODS: Two examiners captured ultrasound images of the non-dominant long head of the biceps tendon and supraspinatus tendon from 15 able-bodied participants and five manual wheelchair users. Each examiner captured two images per subject under two different preparations, which included subject positioning and reference marker placement. Image processing (reading) was performed twice to compute nine quantitative ultrasound measures of grayscale tendon appearance using first-order statistics and texture analysis. Generalizability theory was applied to compute interrater and intrarater reliability using the coefficient of dependability (Phi) for multiple study design protocols. RESULTS: Interrater reliability was generally low (0.26 < Phi < 0.82), and it is recommended that a single evaluator capture all images for quantitative ultrasound protocols. Most of the quantitative ultrasound measures (n = 14 of 18) exhibited at least moderate (Phi > 0.50) intrarater reliability for a single image captured under one preparation and read once. CONCLUSION: By following a protocol designed to minimize measurement error, one can increase the reliability of quantitative ultrasound measures. An appropriately designed protocol will allow quantitative ultrasound to be used as an outcome measure to identify structural changes within tendons.

Shoulder ultrasound abnormalities, physical examination findings, and pain in manual wheelchair users with spinal cord injury.

OBJECTIVES: To investigate the presence of ultrasound (US) abnormalities in manual wheelchair users with spinal cord injury (SCI) using a quantitative Ultrasound Shoulder Pathology Rating Scale (USPRS). To investigate physical examination (PE) findings using a quantitative Physical Examination of the Shoulder Scale (PESS), and to obtain data about pain and other subject characteristics such as age, years with SCI, and weight. DESIGN: Case series. SETTING: National Veterans' Wheelchair Games 2005 and 2006. PARTICIPANTS: Volunteer sample of manual wheelchair users with SCI participating in the National Veterans' Wheelchair Games. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Presence of relationships between US findings, PE findings, pain, and subject characteristics. RESULTS: The USPRS correlated with age, duration of SCI, and weight (all P<.01), and showed a positive trend with the total Wheelchair User's Shoulder Pain Index (WUSPI) score (r=.258, P=.073). Several US findings related to presence of PE findings for specific structures. The PESS score correlated with the WUSPI (r=.679, P<.001) and duration of SCI (P<.05). The presence of untreated shoulder pain that curtailed activity was noted in 24.5% of subjects, and this was related to increased WUSPI scores (P=.002). CONCLUSIONS: PE and US abnormalities are common in manual wheelchair users with SCI. The USPRS and PESS demonstrated evidence for external validity and hold promise as research tools. Untreated shoulder pain is common in manual wheelchair users with SCI, and further investigation of this pain is indicated.

Ultrasound imaging of acute biceps tendon changes after wheelchair sports.

OBJECTIVES: To investigate acute changes in the biceps tendon after a high-intensity wheelchair propulsion activity and to determine whether these changes are related to subject characteristics. DESIGN: The biceps tendon was imaged with ultrasound before and after wheelchair basketball or quad rugby. The average diameter of the tendon was calculated as well as the echogenicity ratio (the pixel intensity ratio of the biceps tendon to a reference just superficial to the tendon sheath). SETTING: National Veterans Wheelchair Games in 2004 and 2005. PARTICIPANTS: Forty-two subjects who participated in wheelchair basketball or quad rugby at the Veterans Games. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Biceps tendon diameter and biceps echogenicity. RESULTS: The echogenicity ratio of the tendon significantly decreased from 1.97 to 1.73 after the event (P=.038). The diameter of the biceps tendon increased from 4.60 to 4.82 mm (P=.178). Also, it was found that the change in tendon diameter positively correlated with the time of play (P=.004). CONCLUSIONS: Acute changes in biceps tendon properties after exercise were found and likely represent edema, a first sign of overuse injury. The significance of continuous activity was shown by the fact that subjects who had more playing time showed a larger increase in tendon diameter.

A kinetic analysis of manual wheelchair propulsion during start-up on select indoor and outdoor surfaces.

The objective of this study was to conduct a kinetic analysis of manual wheelchair propulsion during start-up on select indoor and outdoor surfaces. Eleven manual wheelchairs were fitted with a SMART(Wheel) and their users were asked to push on a course consisting of high- and low-pile carpet, indoor tile, interlocking concrete pavers, smooth level concrete, grass, hardwood flooring, and a sidewalk with a 5-degree grade. Peak resultant force, wheel torque, mechanical effective force, and maximum resultant force rate of rise were analyzed during start-up for each surface and normalized relative to their steady-state values on the smooth level concrete. Additional variables included peak velocity, distance traveled, and number of strokes in the first 5 s of the trial. We compared biomechanical data between surfaces using repeated-measures mixed models and paired comparisons with a Bonferroni adjustment. Applied resultant force (p = 0.0154), wheel torque (p < 0.0001), and mechanical effective force (p = 0.0047) were significantly different between surfaces. The kinetic values for grass, interlocking pavers, and ramp ascent were typically higher compared with tile, wood, smooth level concrete, and high- and low-pile carpet. Users were found to travel shorter distances up the ramp and across grass (p < 0.0025) and had a higher stroke count on the ramp (p = 0.0124). While peak velocity was not statistically different, average velocity was slower for the ramp and grass, which indicates greater wheelchair/user deceleration between strokes. The differences noted between surfaces highlight the importance of evaluating wheelchair propulsion ability over a range of surfaces.

Relation between median and ulnar nerve function and wrist kinematics during wheelchair propulsion.

OBJECTIVE: To investigate the relation between median and ulnar nerve health and wrist kinematics in wheelchair users. DESIGN: Case series. SETTING: Biomechanics laboratory and electrodiagnostic laboratory at a Veterans Health Administration medical center and a university hospital, respectively. PARTICIPANTS: Thirty-five people with spinal cord injury who use manual wheelchairs. INTERVENTION: Subjects propelled their own wheelchair on a dynamometer at 0.9 and 1.8m/s. Bilateral biomechanic data were obtained by using force and moment sensing pushrims and a kinematic system. Bilateral median and ulnar nerve conduction studies were also completed. MAIN OUTCOME MEASURES: Wrist flexion, extension, radial and ulnar deviation peaks, and ranges of motion (ROMs) as related to median and ulnar motor and sensory amplitudes. A secondary analysis included peak pushrim forces and moments and stroke frequency. RESULTS: There was a significant, positive correlation between flexion and extension ROM and both ulnar motor amplitude (r=.383, P<.05) and median motor amplitude (r=.361, P<.05). CONCLUSIONS: Contrary to our hypothesis, subjects using a greater ROM showed better nerve function than subjects propelling with a smaller ROM. Subjects using a larger ROM used less force and fewer strokes to propel their wheelchairs at a given speed. It is possible that long, smooth strokes may benefit nerve health in manual wheelchair users.