Features of the Sinushunt and its influence on the cerebrospinal fluid system.

OBJECTIVES A new cerebrospinal fluid (CSF) shunt system, Sinushunt, has recently been introduced. CSF is shunted from the ventricles to the transverse sinus. The Sinushunt is not a classical differential pressure shunt; instead, it opens as soon as there is a positive pressure over the shunt and the flow is dependent on the resistance of the system, which is high compared with traditional CSF shunts. The objective of this study was to characterise the features of the Sinushunt and to evaluate its influence on the CSF system. METHODS Five brand new Sinushunts with distal catheters were tested. An automated, computerised experimental apparatus based on regulation of pressure, built into an incubator at 37 degrees C, was used. Opening pressure, resistance, and anti-reflux properties were determined. RESULTS The mean (SD) opening pressure was highly dependent on the pressure in the sinus: P(open) = 1.3 (0.6) mm Hg with Psinus = 0.0 mm Hg, and Popen = 7.5 (0.6) mm Hg for Psinus = 6.5 mm Hg. The mean (SD) resistance of the shunts was 7.9 (0.3) mm Hg/ml/min and not clinically significantly affected by the sinus pressure. In one shunt there was reflux, and in another two shunts there was a very small, but similar, tendency. CONCLUSIONS This study confirms that the resistance of the Sinushunt is comparable to the physiological values in humans. However, the optimal post-operative resistance for different hydrocephalus types is unknown, and randomised clinical trials are needed to confirm improved outcome and reduced complication rate for the Sinushunt compared with traditional low resistance ventriculoperitoneal shunts. A weakness of the anti-reflux system of the Sinushunt must be suspected and has to be further investigated.