Discussion on operative skills in the embolization of hydrosalpinx by hysteroscopic placement of a microcoil.

This study aims to discuss the operative skills of hysteroscopic tubal embolization and reduce the occurrence of complications.Ninety-four patients were divided into group A and group B. The main surgical technique in group A: when the inner sleeve is sent to the fallopian tube and no longer accessible (but no >3 cm), remove the guide wire and put into the microcoil. But in group B, there are four major surgical techniques. First, the depth at which the guide wire enters the tube was controlled at 2 cm. Second, the inner diameter of the fallopian tube must be explored to determine the type and shape of the coils. Third, saline should be used to separate the catheter. Fourth, it is to control the release speed of the coils. The superiority of the improved operation method was confirmed by comparing the surgical failure rate, incidence of complications, and cost of surgery before and after the procedure.The reoperation rate of group A was 10% (3/30), while that of group B was 2.68% (3/112). The ectopic microcoils rate of group A was 6.67% (2/30), while that of group B was 0.89% (1/112). The microcoil damages rate of group 23.33% (7/30), while that of group B was 8.04% (9/112). All P values were <.01, and the difference was statistically significant.Hysteroscopic tubal embolization is currently a new surgical procedure to block the fallopian tubes and prevent the reverse flow of fluid in the fallopian tubes into the uterine cavity. After we improved surgical techniques, the surgical failure rate, complication rate, and operation cost of fallopian tube embolization were significantly lower than before the improved method was applied. The improved techniques led to a higher success rate.

Statistical inference of risk difference in K correlated 2 x 2 tables with structural zero.

K correlated 2 x 2 tables with structural zero are commonly encountered in infectious disease studies. A hypothesis test for risk difference is considered in K independent 2 x 2 tables with structural zero in this paper. Score statistic, likelihood ratio statistic and Wald-type statistic are proposed to test the hypothesis on the basis of stratified data and pooled data. Sample size formulae are derived for controlling a pre-specified power or a pre-determined confidence interval width. Our empirical results show that score statistic and likelihood ratio statistic behave better than Wald-type statistic in terms of type I error rate and coverage probability, sample sizes based on stratified test are smaller than those based on the pooled test in the same design. A real example is used to illustrate the proposed methodologies.

Sample size determination for matched-pair equivalence trials using rate ratio.

In this article, we compare Wald-type, logarithmic transformation, and Fieller-type statistics for the classical 2-sided equivalence testing of the rate ratio under matched-pair designs with a binary end point. These statistics can be implemented through sample-based, constrained least squares estimation and constrained maximum likelihood (CML) estimation methods. Sample size formulae based on the CML estimation method are developed. We consider formulae that control a prespecified power or confidence width. Our simulation studies show that statistics based on the CML estimation method generally outperform other statistics and methods with respect to actual type I error rate and average width of confidence intervals. Also, the corresponding sample size formulae are valid asymptotically in the sense that the exact power and actual coverage probability for the estimated sample size are generally close to their prespecified values. The methods are illustrated with a real example from a clinical laboratory study.