Jcy Cheng

Generalized low areal and volumetric bone mineral density in adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) may be associated with generalized low bone mineral status. The bone mineral density (BMD) of 75 girls of 12–14 years of age and diagnosed as having AIS were compared with 94 age‐matched female control subjects. Areal BMD (aBMD) of the lumbar spine (L2‐L4) and the bilateral proximal femur were measured using ‐energy X‐ray absorptiometry (DEXA), and volumetric BMD (vBMD) of the nondominant distal radius and bilateral distal tibias was measured with peripheral quantitative computer tomography (pQCT). Relevant anthropometric parameters and the severity of the spinal deformity (Cobbs angle) also were evaluated and correlated with the BMD measurements. Results revealed the presence of a generalized lower bone mineral status in AIS patients. Detailed analysis showed that the aBMD and vBMD measured at the bilateral lower extremities were significantly lower in AIS patients when compared with the same in the normal controls. The most significant effect was seen in the trabecular BMD (tBMD) of the distal tibias. Of all the AIS girls, 38% of the aBMD and 36% of the vBMD were below −1 SD of the normal. BMD was found to correlate better with “years since menarche” (YSM) than with chronological age. When the BMD was evaluated for the 3 YSM groups, aBMD of the proximal femur and tBMD of distal tibias were found to be significantly lower in the AIS patients. Neither the aBMD nor the vBMD of AIS patients was found to be associated with the severity of spinal deformity. In addition, anthropometric measurements showed significantly longer arm span and lower extremities in the AIS girls. We concluded that the AIS girls had generalized lower aBMDs and vBMDs.

Volume-Based Morphometry of Brain MR Images in Adolescent Idiopathic Scoliosis and Healthy Control Subjects

BACKGROUND AND PURPOSE: Adolescent idiopathic scoliosis (AIS) is a spinal deformity with unknown cause. Previous studies have suggested that subclinical neurologic abnormalities are associated with AIS. The objective of this prospective study was to characterize systematically neuroanatomic changes in patients with left thoracic AIS vs right thoracic AIS and healthy control subjects by using volume-based morphometry. MATERIALS AND METHODS: Our current study involved 9 girls with left thoracic AIS and 20 girls with right thoracic AIS vs 11 and 17 matched female control subjects, respectively. Voxel-based morphometry (VBM), deformation-based morphometry (DBM), and tensor-based morphometry (TBM) were used to analyze the MR images aligned with a specific brain template of local adolescent girls. The statistical t test was used in VBM and TBM, and the Hotelling T2 test was applied in DBM. RESULTS: Using VBM, we found statistically significant differences (P < .05) in the white matter attenuation of the genu of the corpus callosum and left internal capsule (left thoracic AIS < control subjects). In contrast, no significant differences were observed between patients with right thoracic AIS and control subjects. CONCLUSIONS: White matter attenuation in the corpus callosum and left internal capsule, responsible for interhemispheric communication and conduit of the corticothalamic projectional fibers, respectively, were found to be significantly lower in left thoracic AIS compared with control subjects; however, this was not the case in right thoracic AIS. Confirmation of the findings is required in future research, which needs to evaluate the relationship of white matter abnormality to curve laterality, pathogenesis, and prognosis in patients with AIS, with biologic significance and possible therapeutic correction.

Variation in Anisotropy and Diffusivity along the Medulla Oblongata and the Whole Spinal Cord in Adolescent Idiopathic Scoliosis: A Pilot Study Using Diffusion Tensor Imaging

BACKGROUND AND PURPOSE: Disturbed somatosensory evoked potentials have been demonstrated in patients with adolescent idiopathic scoliosis (but this functional delay was found to originate above the C5–6 level, while the lower cord level was unaffected). Together with MR imaging observation of tonsillar ectopia and a relatively tethered cord, we hypothesized that there is disturbed mean diffusivity integrity along the spinal cord. In this study, advanced DTI was used to evaluate whether there was underlying decreased WM integrity within the brain stem and spinal cord in adolescent idiopathic scoliosis and any relationship to cerebellar tonsillar ectopia. Clinical impact on balance testing was also correlated. MATERIALS AND METHODS: Thirteen girls with adolescent idiopathic scoliosis with right thoracic curves were compared with 13 age-matched healthy girls. DTI of the brain and whole spinal cord was performed. ROIs were manually defined for the medulla oblongata and along each intervertebral segment of the cord. Mean values of fractional anisotropy and mean diffusivity were computed at the defined regions. Between-group comparisons were performed by 1-way ANOVA. RESULTS: Significantly decreased fractional anisotropy values and increased mean diffusivity values were found at the medulla oblongata and C1–2, C2–3, C3–4, and C4–5 segments in patients with adolescent idiopathic scoliosis compared with healthy subjects. No significant difference was found in the lower cord levels. Significant correlation was found between the tonsillar level and fractional anisotropy value at the C4–5 level in patients with adolescent idiopathic scoliosis only. CONCLUSIONS: The findings from this study are in agreement with previous findings showing abnormal somatosensory evoked potential readings occurring only above the C5–6 level in patients with adolescent idiopathic scoliosis; these findings might partially explain the pathophysiology of the neural pathway involved.

Contact force ratio: A new parameter to assess foot arch function

Static footprint parameters have been used to quantify arch height with conflicting results. This could be caused by the inherent inaccuracy and variations of the methodology used. Since the foot is a dynamic structure that undergoes changes during a step, it is more desirable to capture and analyse the dynamic footprint at an instant during the gait cycle that can most closely reflect the weight-bearing foot function. Forty (40) volunteer subjects were recruited for the reliability test of a new parameter, the Contact Force Ratio (CFR), derived from dynamic footprint. This is a measure of midfoot loading during gait. The mid-gait dynamic footprints were collected using a pressure sensing mat. Results of ICC tests showed that the CFR had good intratester (0.918) and intertester (0.909) reliability. The validity of the method was examined by correlating the parameter to the functional change in arch height, i.e. the Navicular Drop between the non-weight-bearing and weight-bearing conditions.

A new alignment jig for quantification and prescription of three-dimensional alignment for the patellar-tendon-bearing trans-tibial prosthesis.

Clinically, it is hard to achieve and reproduce prosthesis alignment at will during daily prosthesis fitting. A new alignment jig was designed and developed to facilitate quantification and prescription of prosthesis alignment for patellar-tendon-bearing (PTB) trans-tibial prostheses. The alignment jig provided instantaneous readings of the three-dimensional orientation and position of the socket relative to the prosthetic foot in standardised units. The inter- and intra-tester errors of the alignment jig in measuring prosthesis alignment were evaluated and demonstrated to have good reliability. The alignment jig was recommended to be used clinically after the conventional dynamic alignment procedure to document the prosthesis alignment. Further application of the alignment jig for systematic evaluation of the effects of prosthesis alignment on gait for trans-tibial amputees is suggested.

Lifelong bound feet in China: a quantitative ultrasound and lifestyle questionnaire study in postmenopausal women

Objective The phenomenon of foot binding, also known as ‘lotus feet’, has an enduring and influential history in China. To achieve a man-made smaller foot size, lifelong foot binding may have had adverse effects on the skeleton. We investigated bone properties in postmenopausal women with bound feet, which may provide new information for developing countermeasures for prevention of fragility fractures. Design Population-based cohort study. Participants This study involved 254 postmenopausal women aged 65–80, including 172 with bound feet and 82 age- and gender-matched control subjects, living in a remote region of China. Outcomes Anthropometric, SF-36 Lifestyle Questionnaire and heel quantitative ultrasound (QUS) data were collected for the whole study population. A small subset of two cases was also invited for assessment of bone mineral density and microarchitecture at the distal tibia using high-resolution peripheral quantitative CT (HR-pQCT) and gait and balance tests. Results Women with bound feet had significantly lower QUS values than age-matched women with normal feet; this was supported by HR-pQCT data. However, SF-36 Questionnaire results did not reveal any statistically significant differences in any categorical responses, including physical functioning, general health vitality and physical component summary score, and number of previous fractures. No impairment of body balance was found in the small subset. Conclusions The man-made changes caused by foot binding led to reduced physical activity, making the subjects prone to osteoporosis. Women with bound feet and osteoporosis did not have a higher incidence of fragility fractures than controls. This might be explained by compensation in physical activity to improve body balance, implying the importance of improving or maintaining body balance in overall prevention strategies against fragility fractures.

Curve correction effect of rigid spinal orthosis in different recumbent positions in adolescent idiopathic scoliosis (AIS): A pilot MRI study

In this pilot cross-sectional study, the effectiveness of rigid spinal orthoses in the correction of spinal curvature of 14 patients with moderate adolescent idiopathic scoliosis (AIS) at different recumbent positions (supine, prone, right and left decubitus) was investigated. Using magnetic resonance (MR) imaging and multi-planar reconstruction technique, evaluation of the scoliotic spine in the coronal, sagittal and axial planes and the effect of spinal orthosis on AIS at different recumbent positions was studied. There was significant reduction of coronal Cobbs angle (p < 0.05) with bracing at all four recumbent positions and the maximal reduction was found in the prone position (18% reduction). The sagittal Cobbs angle was only significantly reduced at the supine position while the axial rotation did not change significantly in all positions.

Involvement of CGRP-Positive Nerve Fibers in Consolidation Stage of Distraction Osteogenesis

To investigate the temporal and spatial distribution of calcitonin gene-related peptide (CGRP) positive nerve fibers during the consolidation stage of distraction osteogenesis (DO), twenty New Zealand white rabbits were used for unilateral DO. Distraction started at the 7 th day after osteotomy with 1 mm of length per day. The lengthening lasted for 10 days. Four rabbits were sacrificed at each of the following time point at 7-day, 14-day, 21-day, 28-day and 42-day post-distraction. The entire distraction callus and 2 mm of neighboring cortical bone on the proximal and distal sides was removed en bloc for assessments. The results showed that CGRP-positive nerve fibers were observed in the periosteal, intercortical and endocortical regions at 7-day post-distraction. After that, CGRP-positive nerve fibers were mainly found in the fibrous tissue of periosteal region and bone marrow of bony callus. Moreover, the density of CGRP innervations was significantly higher at 21-day post-distraction than that of other time point. In conclusion, the observed spatial and temporal distribution of CGRP-positive nerve fibers during consolidation stage of DO suggested CGRP innervation is associated with DO.