Ventriculoperitoneal shunt of continuous flow vs valvular shunt for treatment of hydrocephalus in adults

The hydrokinetic parameters of shunts for hydrocephalus might be inadequate

“…This gradient develops as soon as the subject stands up or sits, moving the axis to its vertical position. [4357] These differences can be demonstrated when, in the same individual, a lumbar puncture is made either in the supine posture or while he is sitting. The gravity force greatly modifies the topographical pressure of the fluid inside the ventriculosubarachnoid space when the subject stands; in sharp contrast, the pressure is evenly distributed and identical anywhere inside the space when the subject lies horizontally [Figure 1].…”

“…[4041] Although in the upright position the ventricular pressure might be zero mm H 2 O or even negative, the suction force produced by the siphon effect opens the valve and drains CSF regardless of ventricular hydrokinetic pressure. Theoretically, in the absence of intraventricular pressure, the valve of the shunt should be closed; however, the intense siphon effect produced by the gravity force acting upon the ventriculoperitoneal catheter in the vertical position exerts a negative suction force of –550 mm H 2 O,[57] sufficient by far to open the valve, whose manufacture is usually settled to open at a positive pressure of around 100 mm H 2 O. Once the valve is opened by the suction effect, the CSF is pulled down, the ventricular cavity is emptied, and the ventricles might collapse, thus inducing intracranial hypotension in which the slit ventricle syndrome could develop.…”

“…[5657] This unique catheter was directly connected, in the traditional way, to a common ventricular catheter; no further mechanisms were introduced in this rather simple connection. Performance of this shunt in long-term studies in the experimental laboratory and in patients with hydrocephalus has been superior than in controls with valvular shunts.…”

“…Performance of this shunt in long-term studies in the experimental laboratory and in patients with hydrocephalus has been superior than in controls with valvular shunts. [3535457] Initial laboratory studies under hydrokinetic simulations of physiological conditions[525357] tested several variations of ID of the connecting catheter as unique mechanism for fluid resistance; the precise measure of 0.51 mm ID was shown to comply, under all physiological variations, with the desired drainage capacity. The connecting catheter of very thin ID instead of the usual catheters of wide ID showed in the laboratory to have a daily drainage capacity of approximately 500 ml under conditions that simulated common parameters of intraventricular pressure and siphon effect in humans.…”

Clinical Manifestations, Diagnosis, and Treatment of Neurocysticercosis

“…Nowadays, surgical interventions are restricted largely to the treatment of hydrocephalus by ventriculo-peritoneal shunting [38]. Most cases of viable cysticerci, even those with giant clumps of cysts, can be effectively treated by cysticidal therapy.…”