Development of fetal growth charts in twins stratified by chorionicity and mode of conception: a retrospective cohort study in China / 中华医学杂志(英文版)

BACKGROUND@#Twin pregnancies continue to increase worldwide; however, the current clinical prenatal evaluation for the intrauterine growth of twins still relies on the growth standards of singletons. We attempted to establish a set of fetal biometric references for Chinese twin pregnancies, stratified by chorionicity and conception mode as spontaneously conceived monochorionic diamniotic (SC-MCDA), spontaneously conceived dichorionic diamniotic (SC-DCDA), and assisted reproductive technology dichorionic diamniotic (ART-DCDA) twins.@*METHODS@#From 2016 to 2019, the ultrasonographic fetal biometric measurements were longitudinally collected in pregnant women, including fetal weight, biparietal diameter, head circumference, abdominal circumference, femur length, and humerus length. The linear mixed models were used to test the difference of growth patterns between groups, and the growth curve of each biometric parameter was modeled by a generalized additive model for location scale and shape.@*RESULTS@#A total of 929 twin pregnant women and 2019 singleton pregnant women, met the inclusion criteria. Among twin pregnancies, 148 were SC-MCDA, 215 were SC-DCDA, and 566 were ART-DCDA twins. Overall, SC-DCDA twins grew faster than SC-MCDA twins, while slower than ART-DCDA twins (all P < 0.05), and all of the three groups showed significant differences comparing with singletons, especially during the third trimester. Hence, the customized fetal growth charts of each fetal biometric parameter were, respectively, constructed for SC-MCDA, SC-DCDA, and ART-DCDA twins.@*CONCLUSIONS@#The fetal biometric trajectories demonstrated characteristic patterns according to chorionicity and conception mode. To fill the gap, we modeled fetal biometric parameters for Chinese SC-MCDA, SC-DCDA, and ART-DCDA twin pregnancies, hoping to provide a reference for the further establishment of fetal growth reference values for Chinese twin fetuses.

Biomechanical comparisons between a new avascular necrosis of femaral head stem based on Chinese patients with avascular necrosis and two other designs / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>There is a relatively high failure rate of the femoral component in patients with avascular necrosis at the intermediate-term follow-up. Improving the geometrical fit of the femoral stem against the medullary canal may help to provide long-term survivorship of the hip replacement for patients with avascular necrosis.</p><p><b>METHODS</b>We designed a specific stem, based on morphometric studies of proximal femoral canals in Chinese avascular necrosis patients and evaluated the stem by finite element analyses, comparing the novel stem with two commercially available and commonly used stems.</p><p><b>RESULTS</b>The morphometric data from avascular necrosis patients showed specific geometric differences in the proximal femoral canal, including profile curves in both the sagittal and coronary planes than the patients with femoral neck fracture. The shorter stemmed prostheses (Fitmore(®) and our stem) performed better than the longer stemmed prosthesis (VerSys(®)).</p><p><b>CONCLUSIONS</b>This is the first study to investigate the femoral geometries of Chinese avascular necrosis patients. Our stem provides better stability and is theoretically beneficial to bone ingrowth, which may increase the long-term stability and fixation of the implant.</p>

Bifocal pain in nummular headache: A clinical analysis and literature review

Background: Nummular headache is a new category of primary headache disorder characterized by consistent location, size, and shape of painful areas. The pathogenesis is uncertain. Bifocal painful areas are rare manifestations but may expand the clinical diversity of nummular headache. Methods: The clinical characteristics of 5 bifocal nummular headache patients were reported and those of 11 patients in previous studies were reviewed. Bifocal nummular headache was classifi ed into two types. Type I was defi ned as a simultaneous activation of two painful areas while type II was defi ned as two painful areas occurring in different times. Results: All 16 patients were female, with mean age of onset and initial presentation of 54.7 years and 58.2 years, respectively. There were seven type I and nine type II patients. The parietal area, especially the tuber parietale, was the leading site of involvement in both types of patients. The shape and size of painful areas were also similar between these two groups. There was an equal frequency of ipsilateral and contralateral painful areas. The pain intensity was similar in both types of patients but was milder in new painful areas than in previous painful areas in type II patients. Conclusions: Bifocal nummular headache suggests a central role of nummular headache but does not debunk the peripheral theory of nummular headache. The accumulated fi ndings in bifocal NH patients do not support a generalization of pain occurrence or a reproduction of local process of epicranial neuralgia at multiple sites in nummular headache.