No abstract

For the experimental study of neural tube defect (NTD), a surgical model has advantages over other models in a few aspects. It causes less functional derangement of cells and the NTDs can be made selectively by surgery. The authors planned to use the surgical model for the experimental study of NTD. As the first step for the studies, the chronological changes of morphology during the early postoperative period were investigated using postincubation 3-day chick embryos. The objectives of this study are (1) the morphological evaluation of the surgical model as a method for studies of open NTD, and (2) the observation of morphological changes for the first 24 hours after surgery which include 'overgrowth' appearance and the continuity between the surface ectoderm and the neuroectoderm. The morphological changes were observed by light microscope and scanning electron microscope. Immediately after surgery, typical open NTDs were observed. Morphologically they were very similar to the appearance of spontaneous (non-surgical) open NTDs. The opened neural tubes were everted progressively and they looked rather flat at 24 hours after surgery. Cellular hyperplasia ('overgrowth' appearance) was noted within 24 hours after surgery and became more prominent during the 24 hours. There was increasing continuity between the surface ectoderm and the neural tissue until 24 hours after surgery when the continuity looked almost complete. In conclusion, surgically induced NTDs are morphologically very similar to spontaneous NTDs.(ABSTRACT TRUNCATED AT 250 WORDS)

No abstract

Magnetic resonance imaging offers better visualization for tumors present in the delicate parts of the human body. A pituitary tumor is one of the common types of brain-related tumors located underside the brain. It can be accessed through the nostrils and visualized better using magnetic resonance imaging (MRI). In this work, we present a 6-degree-of-freedom (DOF) robotic system for pituitary tumor resection via a transsphenoidal approach designed specifically for a commercially available 3T MRI scanner. The robotic system is designed to follow the anatomical and surgical constraints and to work inside the bore of the MRI to allow image acquisition during the surgical procedure. It has a 6-DOF manipulator consisting of a concentric tube and a tendon-driven bendable section. Both mechanisms are merged to have stiffness changing capability, and payload capacity to aid the surgical task. The manipulator is attached to a flexure shaft to bend it at the desired surgical angles. The materials used for development are analyzed in MRI and exhibit signal-noise ratio (SNR) reduction of less than 10%. The experimental results show that the stiffness can be changed more than ten times for safe navigation to the surgical site without damaging the surrounding tissues. Also, it can provide a maximum lifting force of more than 2N. The presented system is the preliminary version of the pituitary tumor resection system under development and shows the feasibility to be used in a real surgical environment.