The Effect of Protein and Blood Cells on the Flow-pressure Characteristics of Shunts

Abstract

It has long been assumed that a high cerebrospinal fluid protein concentration adversely affects the performance of shunts. There is little experimental evidence to support this viewpoint, however, and the few reports that have been published can be criticized for poor experimental design or presentation of results. A flow-dependent shunt perfusion model was constructed. PS Medical Flow Control valves (PS Medical Corporation, Goleta, CA) and Cordis-Hakim valves (Cordis Corporates, Miami, FL) were perfused with saline-plasma solutions in concentrations from 0 to 9 g/L of protein. Blood suspensions in dilutions from 0.25 to 1% were also studied. The opening and closing pressures of the valves were measured with a simple manometer, and the physical properties of the solutions were studied. The results indicated that the valves performed within the ranges specified by their manufacturers, even with markedly increased protein concentrations in the perfusate. Furthermore, the valve opening and closing pressures were lower with the protein-containing solutions than with the control solutions. Thus, the protein did not impair shunt function and we conclude that shunts can be inserted into patients who have elevated cerebrospinal fluid protein contents. However, blood cells did adversely affect performance and, therefore, patients with hemorrhagic cerebrospinal fluid should not receive shunts.

Limited Efficacy of Endoscopic Third Ventriculostomy for Hydrocephalus Following Aneurysmal Subarachnoid Hemorrhage

“…16) We also believe that a washout period of red blood cells in CSF, which can cause shunt failure, is also desirable. 1,2) External drainage placement after aneurysmal surgery is often prolonged in our institute, which may induce bacterial colonization, 9) although we did not confirm any cases of meningitis in our study. It is advantageous to wait as long as possible for bacterial elimination before VP shunt implantation.…”

Management of ruptured intracranial aneurysms in the post-ISAT era: outcome of surgical clipping versus endovascular coiling in a Singapore tertiary institution

“…(17) Such blood products can cause physical obstruction within the ventricular system and may lead to microscopic obstruction of the arachnoid granulations, thereby giving rise to hydrocephalus. (18,19) In summary, patients with good-grade aneurysmal SAH undergoing surgical clipping were 1.5 times more likely to have poor outcomes compared to those undergoing endovascular coiling, with an absolute difference of 5.2%. This group of patients was also 1.8 times more likely to require a VP shunt at the end of their six-month follow-up.…”

Nonprogrammable and programmable cerebrospinal fluid shunt valves: a 5-year study

“…Other studies mention biofilm or proteinaceous debris on the valve surface upon removal. 5,6,9,10,17 However, other studies analyzing protein counts in the CSF both in vitro and after complication have shown no significant correlation with shunt failure. 5,6,19 The increased technological Fig.…”

“…15,19 Authors have reported that protein level has no direct relationship to valve failure. [5][6][7]15,19 Using scanning electron microscopy, Brydon et al 5,6 reported that 13% of their 102 explanted valves studied after shunt failure were coated by white, red, or degenerating cells. Most were coated with protein, but the thin coating was not thought to be the cause of shunt failure.…”