Neuropsychological improvement after posterior fossa arachnoid cyst drainage.

PURPOSE: Posterior fossa arachnoid cysts (PFAC) are mostly considered as benign lesions of the cerebellum. Although many studies have shown the major role of the cerebellum in modulating movement, language, cognition, and social interaction, there are few studies on the cognitive impact and surgical decompression of PFAC. METHODS: We present the cases of two brothers successively diagnosed with PFAC and neuropsychological delay. After multidisciplinary discussion with the boys' parents, it was decided to drain these lesions. Clinical signs, cerebral images, and neuropsychological status were assessed on admission and then 1 and 3 years after surgery. RESULTS: At presentation, both children had mild cerebellar signs, associated with cognitive and visual-motor impairments and academic regression. CT scans revealed retrovermian cysts, which were shunted. Post-operatively, both brothers demonstrated improved visual-motor skills and behavior. At follow-up, we observed disappearance of dysarthria and academic delay and significant improvement in cognition especially at the intelligence scale and in language. Fine motor skills had improved but remained slower than the average and writing skills appeared limited. CONCLUSION: Except for PFAC which impair cerebrospinal fluid circulation or which are responsible for a significant mass effect, most PFAC are usually considered as "asymptomatic" and do not require surgical treatment. The two cases reported herein suggest that these lesions might be responsible for some associated but potentially reversible neuropsychological impairment. In the future, clinical assessment should include neuropsychological evaluation to help inform decision for surgical decompression in these children with PFAC.

Hemolytic differences among artificial cardiac valves used in a ventricular assist pump.

Ventricular assist devices (VADs) required for cardiac support may produce clinically significant hemolysis. VAD valves differ in both mechanics and hemodynamics. Therefore, we examined a ball valve, a modified tilting disc (MTD) valve, a polyurethane trileaflet valve, and a Björk-Shiley monostrut valve to determine their degrees of hemolysis. The valves were tested in a Pierce-Donachy VAD which pumped fresh bovine blood through a mock loop. Blood samples were analyzed for hematocrit and plasma hemoglobin, from which the indices of hemolysis were calculated. A one-way analysis of variance indicated significant differences between certain valves. The MTD was the most hemolytic. No significant hemolytic difference was found between the trileaflet and monostrut valves despite their different designs. The monostrut valve and the MTD valve were hemolytically very different despite their similar design. This study suggests that the valve type significantly affects the hemolysis produced by the VAD.