Impact of lower muscle stiffness on ankle dorsiflexion restriction in children with cerebral palsy evaluated using ultrasound elastography.

BACKGROUND: Plantar flexor muscles always contribute to limiting the range of motion of ankle dorsiflexion in children with spastic cerebral palsy, but the individual contributions of these muscles are not well defined. This study aimed to identify which muscles' stiffness impacts the dorsiflexion range of motion in children with cerebral palsy. METHODS: Twenty-five children with cerebral palsy were included. The maximum passive dorsiflexion range of motion was measured in two positions: hip and knee joints in flexion, and both joints in full extension. Strain ratios indicating muscle stiffness were measured using strain elastography of the lateral and medial gastrocnemius, soleus, flexor hallucis longus, peroneus longus, peroneus brevis, and tibialis posterior muscles. To analyze which muscles impact the limitation of the dorsiflexion range, multiple regression analyses were conducted. The values of muscle stiffness were included as independent valuables, and the values of the dorsiflexion range were included as dependent valuables. A p-value <0.05 was considered statistically significant. FINDINGS: In the analyses, the soleus and flexor hallucis longus muscle stiffness were significant independent factors for the dorsiflexion range of motion of hip and knee flexion (adjusted R2: 0.50). The lateral gastrocnemius muscle stiffness was a significant independent factor for the dorsiflexion range of motion with both joints in full extension (adjusted R2: 0.61). INTERPRETATION: Flexor hallucis longus muscle stiffness, in addition to triceps surae muscle stiffness, was shown to impact dorsiflexion range; attention should be paid to muscle stiffness in children with cerebral palsy.

Gait velocity control using projection mapping for children with spastic diplegia cerebral palsy.

BACKGROUND: Gait characteristics in children with cerebral palsy vary according to their individual walking speed. As such, establishing methods to maintain a consistent gait velocity are necessary to evaluate specific intervention effects in this clinical population. Our study aim was to validate the accuracy of projection mapping for guiding gait velocity to a control gait velocity. METHODS: This was a cross-sectional study of 13 children with cerebral palsy (mean age [standard deviation] of 12.42 [2.31] years). The target velocity was calculated from the average speed obtained across three trials of self-selected walking speed. A virtual reality system with four projectors was used to project an image onto the floor to guide children to match two gait conditions: 100% and 125% velocity of the average speed. Participants completed three gait trials at each velocity under image guidance. Gait velocity was quantified using a 3-dimensional motion capture system. Bland-Altman plots were used to analyze systematic errors and the limits of agreement calculated. FINDINGS: The results indicated the limits of agreement were acceptable for 0.10 m/s for 100% velocity and 0.12 m/s for 125% velocity. Therefore, projection mapping was effective in guiding children to adjust their gait to the intended velocity. INTERPRETATION: Projection mapping is a novel method for guiding children with cerebral palsy to walk at a controlled target velocity that may improve the reliability of gait analysis.

Analysis of center of mass and center of pressure displacement in the transverse plane during gait termination in children with cerebral palsy.

BACKGROUND: While gait termination is challenging for children with spastic cerebral palsy (CCP), few studies have quantitatively assessed this issue. RESEARCH QUESTION: What are the characteristics of center of mass (COM) and center of pressure (COP) displacement during gait termination in CCP, and how do they compare with those in children with typical development (CTD)? METHODS: This cross-sectional study included 13 adults with typical development (19.85 ± 0.52 years), 12 CTD (10.41 ± 2.98 years), and 16 CCP (11.15 ± 2.71 years). Participants were instructed to immediately stop walking when a stop sign appeared on a screen, which was placed at the end of an 8-m walkway. COM and COP were determined via 3-dimensional motion analysis and force plate data. Differences between the groups were assessed using the two sample t-test or Wilcoxon rank sum test. The level of statistical significance was set at P < 0.05. RESULTS: The normalized time for stopping in CCP (4.556 ± 0.602) was higher than that in CTD (3.617 ± 0.545, P < 0.001). The normalized COP displacement (P < 0.001) and divergence between COM and COP (P < 0.001) in the mediolateral (ML) direction were significantly higher in CCP than CTD. However, the normalized divergence between COM and COP in the anteroposterior (AP) direction in CCP was lower than that in CTD (P = 0.034). SIGNIFICANCE: The more minor divergence between COM and COP in the AP direction and the more significant COP displacement in the ML direction cause difficulty to exert braking force during gait termination. Thus, CCP require a longer time for gait termination. This finding may facilitate the development of interventions for improving gait in CCP.

Pediatric spinal infection with epidural abscess: A report of two cases.

BACKGROUND: Pediatric spinal infections are rare and often accompanied by abscesses. Delayed diagnosis commonly leads to a poor neurological prognosis, emphasizing the need for early diagnosis and treatment. CASE DESCRIPTION: We report on two cases of spinal infection; one in a 5-year-old boy with a T8-11 epidural abscess and one in a 10-year-old boy with an L5-S1 epidural abscess. Both cases improved with conservative therapy. CONCLUSION: Early magnetic resonance imaging diagnosis and systemic treatment in collaboration with pediatricians are key factors in the successful management of children with spinal infections.

Relationship between walking efficiency and muscular strength of the lower limbs in children with cerebral palsy.

[Purpose] In children with cerebral palsy, despite increases in muscle strength after strengthening, improvements in walking efficiency are inconsistent in previous studies. The purpose of this study was to analyze the relationship between walking efficiency and muscle strength in children with cerebral palsy. [Participants and Methods] Twenty-six children with cerebral palsy participated in this study. Isometric muscle strength in the lower extremities and the Total Heart Beat Index were measured. Participants were divided into the high and low walking efficiency groups based on the median Total Heart Beat Index value (2.06 beats/m). [Results] For all participants, all isometric muscle strength values were significantly correlated with the Total Heart Beat Index. In the high walking efficiency group, there was no significant correlation. All isometric muscle strength values in the low walking efficiency group were significantly correlated with the Total Heart Beat Index, except for that of the hip extensors. [Conclusion] The influence of muscular strength on walking efficiency in children with cerebral palsy varied. Significant correlations were observed only for those in the low walking efficiency group. The walking efficiency level should be confirmed before planning muscle strength training to improve walking efficiency.

The association between the maximum step length test and the walking efficiency in children with cerebral palsy.

[Purpose] To improve walking efficiency could be useful for reducing fatigue and extending possible period of walking in children with cerebral palsy (CP). For this purpose, current study compared conventional parameters of gross motor performance, step length, and cadence in the evaluation of walking efficiency in children with CP. [Subjects and Methods] Thirty-one children with CP (21 boys, 10 girls; mean age, 12.3 ± 2.7 years) participated. Parameters of gross motor performance, including the maximum step length (MSL), maximum side step length, step number, lateral step up number, and single leg standing time, were measured in both dominant and non-dominant sides. Spatio-temporal parameters of walking, including speed, step length, and cadence, were calculated. Total heart beat index (THBI), a parameter of walking efficiency, was also calculated from heartbeats and walking distance in 10 minutes of walking. To analyze the relationships between these parameters and the THBI, the coefficients of determination were calculated using stepwise analysis. [Results] The MSL of the dominant side best accounted for the THBI (R2=0.759). [Conclusion] The MSL of the dominant side was the best explanatory parameter for walking efficiency in children with CP.

Crystal structure and characterization of pyrroloquinoline quinone disodium trihydrate.

BACKGROUND: Pyrroloquinoline quinone (PQQ), a tricarboxylic acid, has attracted attention as a growth factor, and its application to supplements and cosmetics is underway. The product used for these purposes is a water-soluble salt of PQQ disodium. Although in the past, PQQ disodiumpentahydrates with a high water concentration were used, currently, low hydration crystals of PQQ disodiumpentahydrates are preferred. RESULTS: We prepared a crystal of PQQ disodium trihydrate in a solution of ethanol and water, studied its structure, and analyzed its properties. In the prepared crystal, the sodium atom interacted with the oxygen atom of two carboxylic acids as well as two quinones of the PQQ disodium trihydrate. In addition, the hydration water of the prepared crystal was less than that of the conventional PQQ disodium crystal. From the results of this study, it was found that the color and the near-infrared (NIR) spectrum of the prepared crystal changed depending on the water content in the dried samples. CONCLUSIONS: The water content in the dried samples was restored to that in the trihydrate crystal by placing the samples in a humid environment. In addition, the results of X-ray diffraction (XRD) and X-ray diffraction-differential calorimetry (XRD-DSC) analyses show that the phase of the trihydrate crystal changed when the crystallization water was eliminated. The dried crystal has two crystalline forms that are restored to the original trihydrate crystals in 20% relative humidity (RH). This crystalline (PQQ disodium trihydrate) is stable under normal environment.

Osteosarcoma occurring in osteogenesis imperfecta.

We describe a case history of a 24-year-old male with osteogenesis imperfecta (OI) who developed osteosarcoma of the left thigh. High-dose ifosfamide therapy caused marked tumor regression of multiple lung metastases. Immunohistochemically, the tumor cells were diffusely positive for the p53 protein. Mutation of the p53 gene was not detected by direct genomic sequencing of exons 4-8. The radiographic characteristics, including irregularly distributed osteolytic lesions and cortical discontinuity, should not be confused with hyperplastic callus formation, a benign process. A biopsy is critical to establish the differential diagnosis between osteosarcoma and common hyperplastic callus formation in OI; however, it must be applied with great care.