Development and testing of an endoscopic pseudo-viewpoint alternating system

Purpose

   An endoscopic system is needed that presents informative images irrespective of the surgical situation and the number of degrees of freedom in endoscopic manipulation. This goal may be achieved with a virtual reality view for a region of interest from an arbitrary viewpoint. An endoscopic pseudo-viewpoint alternation system for this purpose was developed and tested.

Method

   Surgical experts and trainees from an endoscopic surgery training course at the minimally invasive surgery training center of Kyushu University were enrolled in a trial of a virtual reality system. The initial viewpoint was positioned to approximate the horizontal view often seen in laparoscopic surgery, with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$20^{\circ }$$\end{document}20∘ between the optical axis of the endoscope and the task surface. A right-to-left suturing task with right hand, based on a task from the endoscopic surgery training course, was selected for testing. We compared task outcomes with and without use of a new virtual reality-viewing system.

Result

   There was a 0.37 mm reduction in total error (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p = 0.02$$\end{document}p=0.02) with use of the proposed system. Error reduction was composed of 0.1 mm reduction on the y-axis and 0.27 mm reduction on the x-axis. Experts benefited more than novices from use of the proposed system. Most subjects worked at a pseudo-viewpoint of around 34\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ $$\end{document}∘.

Discussion

   Suturing performance improved with the new virtual reality endoscopic display system. Viewpoint alternation resulted in an overview that improved depth perception and allowed subjects to better aim the marker. This suggests the proposed method offers users better visualization and control in endoscopic surgery.

Association between the HER2 expression and histological differentiation in Wilms tumor

Human epidermal growth factor receptors (HER) play a critical role in the branching morphogenesis of renal tubules. In the current study, we analyzed the expression of HER2 in Wilms tumor and assessed the role of this gene in the tumorgenesis of Wilms tumor. During the period from 1960 to 2005, 40 patients with Wilms tumor were treated in our department. Twenty-four of those patients (except those with clear cell sarcoma of the kidney and malignant rhabdoid tumor of the kidney) were collected and assessed. The histological component of each Wilms tumor was divided into three categories (epithelial, blastemal, and mesenchymal) and the extent of HER2 protein expression was analyzed immunohistochemically. The normal kidney tissue accompanied with 12 cases of Wilms tumor was also examined. In the normal kidney, HER2 showed a strong immunoreactivity in the cell membranes of the collecting tubules and in the endothelial cells. Of 24 cases, 15 cases showed an epithelial component, while 24 cases had a blastemal component and 21 cases had a mesenchymal component, respectively. Among the 15 specimens with epithelial cell differentiation, eight (53.3%) showed HER2 immunoreactive epithelial cells. HER2 immunoreactive blastemal cells were present in 11 (45.8%) of 24 specimens with blastemal cells. On the other hand, only 3 (14.3%) of 21 specimens containing mesenchymal cells showed HER2 immunoreactivity. These results suggest that the extent of HER2 expression is associated with epithelial differentiation in Wilms tumor. These histological findings may therefore help to explain the development of Wilms tumor from the standpoint of histological differentiation.