No abstract

Background?Minimized frontal and frontolateral approaches have been proposed for the clipping of aneurysms and for removal of deep-seated supra- and parasellar lesions. To avoid postoperative facial nerve palsy, anatomical studies have been conducted; however, only one electrophysiological investigation has been reported. We studied the course of the facial nerve in the temporal region and identify the optimal pterional keyhole craniotomy from the perspective of facial nerve protection. Materials and Methods?We stimulated the temporal branch of the facial nerve in nine healthy volunteers and identified its course electrophysiologically. Electromyographic (EMG) responses were recorded from the superior orbicularis oculi, corrugator, and frontal muscles. The course of the temporal branch of the facial nerve was identified by tracking the stimulation points that elicited the best EMG responses. Results and Conclusion?The distances from the tragus to the canthus, the tragus to the point where the facial nerve crosses over the zygomatic arch, the tragus to the first nerve bifurcation, the tragus to the second nerve bifurcation, and from the orbit to the middle rami were 80.8???1.8?mm, 40.2???1.6?mm, 58.1???2.8?mm, 79.1???3.4?mm, and 16.4???0.9?mm, respectively. We found that the temporal branch of the facial nerve innervates each muscle in posterior-anterior direction. Based on these results, we prefer the pterional keyhole approach and incise the skin at a site posterior to the temporal branch of the facial nerve.

ABSTRACT-Kabatana takedai (Microspora) is known as an enzootic pathogen of salmonids in limited water systems such as the Chitose River in Hokkaido, northern Japan. In this study, susceptibility to K. takedai was compared among masu salmon Oncorhynchus masou originating from the Chitose River, Shiribetsu River and Shari River, and rainbow trout O. mykiss from Shizuoka Prefecture, Japan. After exposure of fish to the Chitose River water, cysts of K. takedai in the heart and trunk muscle were examined by microscopy. Prevalence and intensity of infection were not considerably different among the three populations of masu salmon, whereas rainbow trout was more susceptible to K. takedai than masu salmon, particularly in the heart. A newly developed PCR test showed the higher percentage of fish with pre-cyst stage of K. takedai in the heart of rainbow trout than in masu salmon, suggesting that K. takedai established the cardiac infection at early stages more in rainbow trout than in masu salmon. A histopathological observation indicated that K. takedai infection in the heart caused granulomatous inflammation characterized by fibrinoid degeneration, but there was no difference in the progress of the inflammation between the two fish species.