Assessment of Median Nerve Mobility by Ultrasound Dynamic Imaging for Diagnosing Carpal Tunnel Syndrome.

Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy and is characterized by median nerve entrapment at the wrist and the resulting median nerve dysfunction. CTS is diagnosed clinically as the gold standard and confirmed with nerve conduction studies (NCS). Complementing NCS, ultrasound imaging could provide additional anatomical information on pathological and motion changes of the median nerve. The purpose of this study was to estimate the transverse sliding patterns of the median nerve during finger movements by analyzing ultrasound dynamic images to distinguish between normal subjects and CTS patients. Transverse ultrasound images were acquired, and a speckle-tracking algorithm was used to determine the lateral displacements of the median nerve in radial-ulnar plane in B-mode images utilizing the multilevel block-sum pyramid algorithm and averaging. All of the averaged lateral displacements at separate acquisition times within a single flexion-extension cycle were accumulated to obtain the cumulative lateral displacements, which were curve-fitted with a second-order polynomial function. The fitted curve was regarded as the transverse sliding pattern of the median nerve. The R2 value, curvature, and amplitude of the fitted curves were computed to evaluate the goodness, variation and maximum value of the fit, respectively. Box plots, the receiver operating characteristic (ROC) curve, and a fuzzy c-means clustering algorithm were utilized for statistical analysis. The transverse sliding of the median nerve during finger movements was greater and had a steeper fitted curve in the normal subjects than in the patients with mild or severe CTS. The temporal changes in transverse sliding of the median nerve within the carpal tunnel were found to be correlated with the presence of CTS and its severity. The representative transverse sliding patterns of the median nerve during finger movements were demonstrated to be useful for quantitatively estimating median nerve dysfunction in CTS patients.

Comparison of Barefoot Walking and Shod Walking Between Children with and Without Flat Feet.

BACKGROUND: We sought to investigate the effect of wearing shoes on joint range of motion, ground reaction force (GRF), and muscle activity (electromyography) in children with flat and normal feet during walking. METHODS: Nine children with flat feet and 12 children with normal feet aged 5 to 11 years were recruited. Each child was instructed to walk on a walkway in the barefoot and shod conditions. Joint range of motion, GRF, and electromyographic data within one gait cycle were collected simultaneously. Two-way analysis of variance was performed to evaluate the effects of foot type and shoe condition on the response measures. RESULTS: Children with flat feet had greater joint motion and higher muscle activities in the lower extremity, as well as lower vertical GRF and longer duration of the first peak forces in vertical and mediolateral GRFs than children with normal feet while walking. Compared with the barefoot condition, shoe wearing in both groups of children showed an increase in ankle dorsiflexion at heel strike, a decrease in anteroposterior GRF and its duration, and an increase in leg muscle electromyographic activities. Pelvic tilt range of motion was affected by the interaction of foot type and shoe condition. CONCLUSIONS: Gait performance in pelvic tilt, hip flexion, and ankle dorsiflexion were different between the two groups of children. Wearing shoes increased the muscle activities of the shin. This finding can provide important information for clinical assessment of and shoe design for children with flat feet.

Association between the volume of inpatient rehabilitation therapy and the risk of all-cause and cardiovascular mortality in patients with ischemic stroke.

OBJECTIVE: To investigate the relationship between the volume of inpatient rehabilitation therapy and mortality among patients with acute ischemic stroke, as well as to assess whether the association varies with respect to stroke severity. DESIGN: A retrospective study with a cohort of consecutive patients who had acute ischemic stroke between January 1, 2008, and June 30, 2009. SETTING: Referral medical center. PARTICIPANTS: Adults with acute ischemic stroke (N=1277) who were admitted to a tertiary hospital. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Stroke-related mortality. RESULTS: During the median follow-up period of 12.3 months (ranging from January 1, 2008, to December 31, 2009), 163 deaths occurred. Greater volume of rehabilitation therapy was associated with a reduced risk of all-cause and cardiovascular mortality (P for trend <.001 for both). Compared with the first tertile, the third tertile of rehabilitation volume was associated with a 55% lower risk of all-cause mortality (hazard ratio [HR]=.45; 95% confidence interval [CI], .30-.65) and a 50% lower risk of cardiovascular mortality (HR=.50; 95% CI, .31-.82). The association did not vary with respect to stroke severity (P for interaction = .45 and .73 for all-cause and cardiovascular mortality, respectively). CONCLUSIONS: The volume of inpatient rehabilitation therapy and mortality were significantly inversely related in the patients with ischemic stroke. Thus, further programs aimed at promoting greater use of rehabilitation services are warranted.

Carpal tunnel syndrome diagnosis by a self-normalization process and ultrasound compound imaging.

PURPOSE: Carpal tunnel syndrome (CTS) is the common entrapment neuropathy that occurs due to compression of the median nerve at the wrist. Ultrasound images have been used to highlight anatomical variants of the median nerve, and CTS is thought to be associated to enlargement of the cross-sectional area (CSA) of the median nerve. However, there remains controversy regarding the most appropriate cutoff values of the computer measurements including the CSA, flattening ratio, and palmar bowing of median nerve, especially given that they can be influenced by image artifacts and factors that differ between individual patients. This study proposed a modified ultrasound compound imaging technique by moving fingers to reduce image artifacts, and the estimates of the normalized CSA [i.e., CSA at the wrist (CSAw) to CSA at the midforearm] with the aim of reducing discrepancies in CSA estimates and improving the ability of CTS discrimination. METHODS: The subjects were examined with their arms supine and while they were making repetitive movements of their fingers (from an open palm into a clenched fist) within 3 s. By a commercial ultrasound scanner with a 10-MHz linear array transducer, a total of 70 images were acquired in each subject. The frame rate of ultrasound system was 25 fps. Nine frames in the acquisition sequence that had produced partial speckle decorrelation were incoherently added to form a compound image, and the inplane motion of them was corrected using the multilevel block-sum pyramid algorithm. The manual contours outlined by ten experimenters and three physicians were used to test the performance in determining the boundary of the median nerve. The receiver operating characteristic (ROC) curve was used to evaluate the usefulness of the estimates in distinguishing healthy volunteers from CTS patients. RESULTS: The manual contours of the median nerve in the compound images had an average area overlap exceeding 90% and relatively small area errors. The areas under the ROC curve obtained using the CSAw estimates for the original and compound images were 0.60 ± 0.09 (mean ± standard error) and 0.80 ± 0.05, respectively; that using normalized CSA estimates for the original and compound images were 0.76 ± 0.04 and 0.89 ± 0.04, respectively. The results show that variations in the CSAw values of compound images for healthy overweight and obese subjects can adversely influence CTS diagnosis, but that this can be overcome using the normalized CSA estimate of compound images. CONCLUSIONS: Compound imaging provides images of superior quality for determining the location of the median nerve boundary. Using the normalized CSA estimate would assist in eliminating problems associated with variability between populations, since the subject becomes his or her own internal control, thereby improving the ultrasound-based diagnosis of CTS.

Flatfoot prevalence and foot dimensions of 5- to 13-year-old children in Taiwan.

BACKGROUND: The prevalence of flatfeet in normal and obese children has not been studied well in the past. The prevalence of flatfoot and foot dimensions of school children in Taiwan were investigated in this study. MATERIALS AND METHODS: One thousand twenty-four school children (549 boys and 475 girls) aged 5 to 13 years participated in this study. Fifteen foot dimensions were measured using a 3D coordinate measuring probe, digital tape measure and Harris mat imprint. Two-way ANOVA was conducted to evaluate the flatfoot and obesity effects on foot dimensions as well as on the change in foot size between weightbearing and nonweightbearing conditions. RESULTS: The prevalence of flatfoot for 5- to 13-year-old children was 28% with a decreasing trend with age. Boys had a significantly higher frequency for flatfoot than girls (chi-square = 26.3; p < 0.001). The prevalence of flatfoot was 35% in boys and 20% in girls. The percent of overweight and obese children was 20%. A significant difference in the prevalence of flatfoot occurred between normal-weight (27%), overweight (31%), and obese (56%) children (chi-square = 18.0; p < 0.001). The obesity effect was significant (p < 0.01) for most foot dimensions. However, the flatfoot effect was only significant (p < 0.05) on foot height for both genders. CONCLUSION: Obese children have a higher frequency of flatfoot, greater foot dimensions, and less change in foot width with weightbearing than normal weight children. Children with flatfeet have a lower foot height and greater foot length change than children with normal feet with weightbearing.