Estimation of sample size and testing power (Part 7)

Hu, Lianxi; Bao, Xiao-lei; Guan, Xue

doi:10.3736/jcim20120405

Cited by 2 publications

(1 citation statement)

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“…Differences in the measured properties among different groups were analyzed by two‐way non‐parametric analysis of variance (ANOVA), Scheirer‐Ray‐Hare test using SPSS Version 19.0 (SPSS GmbH, Munich, Germany). In order to assess the probability of a Type II error (false negative, known as β ), retrospective statistical power analysis was performed for each variable based on a sample size of 5, at a significance α level of 0.05, actual difference observed in our study according to the method described by Hu et al Furthermore, if there were significant differences among the different groups, a pairwise t ‐test was used to compare similar variables between groups at each time point and Bonferroni adjustment was used to reduce the probability of Type I error (false positive) of multiple comparisons. After Bonferroni adjustment procedure, the significance value for individual tests was set at p < 0.017 ( α adj = α / m , where m is the number of tests).…”

Section: Methodsmentioning

confidence: 99%

Locally injection of cell sheet fragments enhances new bone formation in mandibular distraction osteogenesis: A rabbit model

Liu

Yao

et al. 2013

Journal Orthopaedic Research

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Effective methods to shorten the treatment period of distraction osteogenesis (DO) are needed. To investigate whether injections of osteogenic bone marrow stromal cell (BMSC) sheet fragments could be used to facilitate new bone formation during DO, 30 rabbits underwent bilateral mandibular osteotomy and their mandibles were lengthened at a rate of 0.75 mm/12 h for 6 days after a 5-day latency period. There were three treatment groups (n ¼ 10 for each group): Serum-free medium, dissociated BMSCs, and BMSC sheet fragments. A local injection was conducted with a needle directly into the distracted areas immediately after distraction. Rabbits were sacrificed for examination at 3 and 6 weeks after injection. Gross examination, radiographic evaluation, and micro-CT scanning indicated a significant increase in bony union in the BMSC sheet fragment group, compared with the medium group and the dissociated cell group. The histomorphometric analysis showed more intensive bone formation in the sheet fragment group than the other two groups at each time point. Additionally, the peak load was significantly higher in the fragment group than those in the others. The results show that injection of BMSC sheet fragments promotes bone formation in DO and indicate a promising approach to shorten the treatment period of osteodistraction. #

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Section: Methodsmentioning

confidence: 99%