Dr. Quigley's remarks are accurate. In our study (1), the aim of the clinical research was not to conduct a confirmatory study, but, rather, an exploratory one, with regard to the possibility of assessment from simple clinical findings.
The percentages of ruptured cases were Type-B, 69%; Type-C, 40%; and Type-A, 28%; consequently, the 3×2 χ2 yields a P value of 0.0365, as mentioned by Dr. Quigley. We avoided drawing a definitive conclusion about comparisons in each group because of the small numbers in our study; for example, there were only 5 cases in Type-C.
As a result of the χ2 comparisons, Type-A versus Type-B, Type-A versus Type-C, and Type-B versus Type-C had P values of 0.025, 1.000, and 0.530, respectively. There was no statistical significance with a Bonferroni correction, but the results suggested the possibility of different risks of rupture, between Type-A and Type-B in particular. As a next step, we are considering confirmatory research to obtain clinically “significant” data.
1. Ohshima T, Miyachi S, Hattori K, Takahashi I, Ishii K, Izumi T, Yoshida J: Risk of aneurysmal rupture: The importance of neck orifice positioning—Assessment using computational flow simulation. Neurosurgery 62:767–775, 2008.