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  • Author or Editor: Junko Matsuyama x
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Brian Willis, Vijayakumar Javalkar, Prasad Vannemreddy, Gloria Caldito, Junko Matsuyama, Bharat Guthikonda, Papireddy Bollam and Anil Nanda


The aim of the study was to analyze the outcome of surgical treatment for posthemorrhagic hydrocephalus in premature infants.


From 1990 to 2006, 32 premature infants underwent surgical treatment for posthemorrhagic hydrocephalus, and their charts were retrospectively reviewed to analyze the complications and outcome with respect to shunt revisions. Multivariate analysis and time series were used to identify factors that influence the outcome in terms of shunt revisions.


The mean gestational age was 27 ± 3.3 weeks, and mean birth weight was 1192 ± 660 g. Temporary reservoir placement was performed in 15 patients, while 17 underwent permanent CSF diversion with a ventriculoperitoneal (VP) shunt. In 2 patients, reservoir tapping alone was sufficient to halt the progression of hydrocephalus; 29 patients received VP shunts. The mean follow-up period was 37.3 months. The neonates who received VP shunts first were significantly older (p = 0.02) and heavier (p = 0.04) than those who initially underwent reservoir placement. Shunts were revised in 14 patients; 42% of patients in the reservoir group had their shunts revised, while 53% of infants who had initially received a VP shunt required a revision. The revision rate per patient in the reservoir group was half that in the direct VP shunt group (p = 0.027). No patient in the reservoir group had > 2 revisions. Shunt infections developed in 3 patients (10.3%), and 2 patients in the reservoir group died of nonneurological issues related to prematurity.


Birth weight and age are useful parameters in decision making. Preterm neonates with low birth weights benefit from initial CSF drainage procedures followed by permanent CSF diversion with respect to the number of shunt revisions.

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Sumito Okuyama, Shinjitsu Nishimura, Yoshiharu Takahashi, Keiichi Kubota, Takayuki Hirano, Ken Kazama, Masato Tomii, Junko Matsuyama, Junichi Mizuno, Tadao Matsushima, Masataka Sato and Kazuo Watanabe


Hypoperfusion during carotid artery cross-clamping (CC) for carotid endarterectomy (CEA) may result in the major complication of perioperative stroke. Median nerve somatosensory evoked potential (MNSSEP) monitoring, which is an established method for the prediction of cerebral ischemia, has low sensitivity in detecting such hypoperfusion. In this study the authors sought to explore the limitations of MNSSEP monitoring compared to tibial nerve somatosensory evoked potential (TNSSEP) monitoring for the detection of CC-related hypoperfusion.


The authors retrospectively analyzed data from patients who underwent unilateral CEA with routine shunt use. All patients underwent preoperative magnetic resonance angiography and were monitored for intraoperative cerebral ischemia by using MNSSEP, TNSSEP, and carotid stump pressure during CC. First, the frequency of MNSSEP and TNSSEP changes during CC were analyzed. Subsequently, variables related to stump pressure were determined by using linear analysis and those related to each of the somatosensory evoked potential (SSEP) changes were determined by using logistic regression analysis.


A total of 94 patients (mean age 74 years) were included in the study. TNSSEP identified a greater number of SSEP changes during CC than MNSSEP (20.2% vs 11.7%; p < 0.05). Linear regression analysis demonstrated that hypoplasia of the contralateral proximal segment of the anterior cerebral artery (A1 hypoplasia) (p < 0.01) and hypoplasia of the ipsilateral precommunicating segment of the posterior cerebral artery (P1 hypoplasia) (p = 0.02) independently and negatively correlated with stump pressure. Both contralateral A1 hypoplasia (OR 26.25, 95% CI 4.52–152.51) and ipsilateral P1 hypoplasia (OR 8.75, 95% CI 1.83–41.94) were independently related to the TNSSEP changes. However, only ipsilateral P1 hypoplasia (OR 8.76, 95% CI 1.61–47.67) was independently related to MNSSEP changes.


TNSSEP monitoring appears to be superior to MNSSEP in detecting CC-related hypoperfusion. Correlation with stump pressure and SSEP changes indicates that TNSSEP, and not MNSSEP monitoring, is a reliable indicator of cerebral ischemia in the territory of the anterior cerebral artery.