Flow characteristics of cerebrospinal fluid shunt tubing

2012 ◽  
Vol 9 (2) ◽  
pp. 191-197 ◽  
Author(s):  
Joseph T. Cheatle ◽  
Alexis N. Bowder ◽  
Sandeep K. Agrawal ◽  
Michael D. Sather ◽  
Leslie C. Hellbusch
Keyword(s):  
Cerebrospinal Fluid ◽  
Flow Characteristics ◽  
Hydrodynamic Resistance ◽  
Csf Shunt ◽  
Effective Diameter ◽  
Cerebrospinal Fluid Shunt ◽  
Shunt System ◽  
Shunt Valve ◽  
Cross Sectional ◽  
Distal Catheter

Object Cerebrospinal fluid shunt systems malfunction for a multitude of reasons, including malpostitioning, obstruction of the ventricular or distal catheter, obstruction of the shunt valve, and catheter disruptions or disconnections. The goal of this study was to examine the hydrodynamic resistance and flow in new and explanted catheters and also in catheters with 1 or 2 straight connectors. Methods Explanted catheters of multiple lengths, 2-piece catheters, 3-piece catheters, and new catheters were attached to a proximal and distal manometer. A flask with artificial CSF attached to the proximal end provided flow. The flow was allowed to stabilize over 1 hour; then the change in pressure between the proximal and distal end of the catheter was measured. Results The resistance to flow was calculated for new, never-implanted catheters and compared with the resistance of explanted distal shunt catheters. The resistance of the new catheters was examined after the addition of 1 and 2 straight connectors. Explanted catheters exhibited a slight increase in the resistance to flow of artificial CSF compared with new catheters. Two-piece and 3-piece catheters had a significant increase in resistance to flow compared with new catheters. For all catheters, resistance to flow increased as length increased (new, p = 0.01; explanted, p = 0.009; 1 connector, p = 0.01; 2 connectors, p = 0.03). In this paper, effective diameter is defined as the available cross-sectional area of catheter contacted by the artificial CSF. For new and explanted catheters, a decrease in the effective diameter of the catheter was associated with an increase in the resistance to flow of artificial CSF (new, p = 0.1083; explanted, p = 0.0091). However, after the addition of 1 or 2 connectors, an inverse trend was observed: resistance to flow increased with effective diameter. Conclusions There appears to be some increase in resistance of CSF shunt catheters as they age, altering flow dynamics. In addition, the use of straight connectors within a CSF shunt system increases the resistance to flow of artificial CSF within the shunt system. The increase in resistance appears to be related to the duration of implantation and the length of the catheter and inversely related to the diameter of the catheter. This increase in resistance may be related to sterile shunt malfunction. The addition of straight connectors is associated with a significant increase in resistance in comparison with catheters without connectors (p = 0.005).

scholarly journals Survival and failure trends of cerebrospinal fluid shunts with distal slit valves: comparative study and literature review

2020 ◽  
Vol 25 (3) ◽  
pp. 209-216
Author(s):  
Jeremy S. Wetzel ◽  
Alex D. Waldman ◽  
Pavlos Texakalidis ◽  
Bryan Buster ◽  
Sheila R. Eshraghi ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Failure Rate ◽  
Csf Shunt ◽  
Time To Failure ◽  
Survival Curves ◽  
Mean Time To Failure ◽  
Distal Catheter ◽  
Catheter Obstruction ◽  
Shunt Survival ◽  
Mean Time

OBJECTIVEThe malfunction rates of and trends in various cerebrospinal fluid (CSF) shunt designs have been widely studied, but one area that has received little attention is the comparison of the peritoneal distal slit valve (DSV) shunt to other conventional valve (CV) type shunts. The literature that does exist comes from older case series that provide only indirect comparisons, and the conclusions are mixed. Here, the authors provide a direct comparison of the overall survival and failure trends of DSV shunts to those of other valve type shunts.METHODSThree hundred seventy-two new CSF shunts were placed in pediatric patients at the authors’ institution between January 2011 and December 2015. Only ventriculoperitoneal (VP) shunts were eligible for study inclusion. Ventriculoatrial, lumboperitoneal, cystoperitoneal, subdural-peritoneal, and spinal shunts were all excluded. Rates and patterns of shunt malfunction were compared, and survival curves were generated. Patterns of failure were categorized as proximal failure, distal failure, simultaneous proximal and distal (proximal+distal) failure, removal for infection, externalization for abdominal pseudocyst, and addition of a ventricular catheter for loculated hydrocephalus.RESULTSA total of 232 VP shunts were included in the final analysis, 115 DSV shunts and 117 CV shunts. There was no difference in the overall failure rate or time to failure between the two groups, and the follow-up period was statistically similar between the groups. The DSV group had a failure rate of 54% and a mean time to failure of 17.8 months. The CV group had a failure rate of 50% (p = 0.50) and a mean time to failure of 18.5 months (p = 0.56). The overall shunt survival curves for these two groups were similar; however, the location of failure was significantly different between the two groups. Shunts with DSVs had proportionately more distal failures than the CV group (34% vs 14%, respectively, p = 0.009). DSV shunts were also found to have proximal+distal catheter occlusions more frequently than CV shunts (23% vs 5%, respectively, p = 0.005). CV shunts were found to have significantly more proximal failures than the DSV shunts (53% vs 27%, p = 0.028). However, the only failure type that carried a statistically significant adjusted hazard ratio in a multivariate analysis was proximal+distal catheter obstruction (CV vs DSV shunt: HR 0.21, 95% CI 0.05–0.81).CONCLUSIONSThere appears to be a difference in the location of catheter obstruction leading to the malfunction of shunts with DSVs compared to shunts with CVs; however, overall shunt survival is similar between the two. These failure types are also affected by other factors such etiology of hydrocephalus and endoscope use. The implications of these findings are unclear, and this topic warrants further investigation.

Stretching and breaking characteristics of cerebrospinal fluid shunt tubing

2003 ◽  
Vol 98 (3) ◽  
pp. 578-583 ◽  
Author(s):  
Daniel J. Tomes ◽  
Leslie C. Hellbusch ◽  
L. Russell Alberts
Keyword(s):  
Cerebrospinal Fluid ◽  
Applied Stress ◽  
Revision Surgery ◽  
Csf Shunt ◽  
Stress And Strain ◽  
Sectional Area ◽  
Cross Sectional ◽  
Content Type ◽  
Shunt Tubing ◽  
Fine Print

Object. Cerebrospinal fluid (CSF) shunt system malfunction due to silastic tubing fracture necessitates revision surgery in shunt-dependent individuals. The goal of this study was to examine the mechanical stretching and breaking characteristics of new and used CSF shunt tubing catheters to determine if any inherent physical properties predispose the tubing to fracture. Methods. Fifty-millimeter segments of new and retrieved (used) CSF shunt tubing were stretched to 120 mm in a hydraulic press to determine modulus values (modulus = stress/strain) and to measure permanent tubing deformation imparted by the applied stress and strain. Similar 50-mm tubing segments were also stretched in an electromechanical material testing system until fracture occurred; the force and strain needed to break the tubing was recorded at the time of failure. The results demonstrate that shunt tubing with a greater cross-sectional area requires greater force to fracture, and that catheters become weaker the longer they are implanted. Barium-impregnated shunt tubing, compared with translucent tubing, appears to require less applied stress and strain to break and may fracture more easily in vivo. The variety of modulus values obtained for the new catheters tested indicates that the various companies may be using materials of different quality in tubing manufacture. Conclusions. A CSF shunt catheter design that incorporates tubing with a greater cross-sectional area may lead to fewer fractures of indwelling catheters and a reduction in shunt revision surgery.

Determination of cerebrospinal fluid shunt function with water-soluble contrast medium

1978 ◽  
Vol 49 (3) ◽  
pp. 398-407 ◽  
Author(s):  
Mario Savoiardo ◽  
Carlo L. Solero ◽  
Angelo Passerini ◽  
Franco Migliavacca
Keyword(s):  
Cerebrospinal Fluid ◽  
Contrast Medium ◽  
Water Soluble ◽  
Ventricular Catheter ◽  
Cerebrospinal Fluid Shunt ◽  
Distal Catheter ◽  
Content Type ◽  
Water Soluble Contrast ◽  
Water Soluble Contrast Medium

✓ Determination of cerebrospinal fluid shunt patency with water-soluble contrast medium is a simple, rapid, reliable, and safe technique. Since September, 1974, the authors performed 113 examinations. With the Spitz-Holter valve, only the atrial catheter can be studied, but, with the Pudenz valve and with the shunting devices that have a double-dome reservoir, both the proximal and the distal catheter can be visualized. Through the ventricular catheter a full ventriculographic study can be made, demonstrating ventricular size, malposition of the catheter, and the lesion that caused the hydrocephalus, or its evolution. The problem of collapsed ventricles, in which clinical and “manual” evaluation of the flushing device can give misleading findings, is emphasized. The injection of the atrial or peritoneal catheter in the pathological cases demonstrated its blockage, level of disconnection, malposition, sleeve, or cyst formation. Computerized tomography has only slightly decreased the number of these studies: when the ventricles are large, the examination with water-soluble contrast medium is still needed to demonstrate the exact level of malfunction. This demonstration has decreased the number of the total revisions or complete changes of shunting systems, eliminating some unnecessary changes of normally functioning catheters.

scholarly journals Modular Redundancy for Cerebrospinal Fluid Shunts: Reducing Incidence of Failure due to Catheter Obstruction

2019 ◽  
Author(s):  
Tom Viker ◽  
Jim Stice
Keyword(s):  
Cerebrospinal Fluid ◽  
Low Cost ◽  
Shunt Revision ◽  
Csf Shunt ◽  
Cerebrospinal Fluid Shunts ◽  
Distal Catheter ◽  
Catheter Occlusion ◽  
Single Lumen ◽  
Catheter Obstruction ◽  
Lumen Catheter

Cerebrospinal fluid shunts for the treatment of hydrocephalus fail at a rate of 40% within the first year. The importance of this problem is supported by one institution’s analysis of neurosurgical 30-day readmissions with CSF shunt failure only second to brain tumor readmissions. Hospital shunt related costs have been estimated at $1.4 to $2 billion annually. The majority of these costs are attributable to shunt failures based on the number of revisions out of the total numbers of annual shunt procedures. The technical innovation of this project is a low cost, low risk and easy to implement CSF shunt design change compatible with current protocols. The proposed product is an innovative distal catheter to minimize the need for revision surgery due to obstruction (also referred to as occlusion). This is accomplished with a dual lumen catheter (current distal catheters are single lumen) consisting of a primary lumen and a secondary lumen providing redundant functionality in the event ofprimary lumen occlusion thereby eliminating the need for surgical shunt revision. 40% of shunts fail within the year after implant and distal catheter obstruction accounts for up to 24% of failures. Though less prevalent than proximal catheter occlusion, incidence of distal catheter occlusion is significant and improved reliability would reduce costs and improve patient outcomes by lowering the number of revisions.

A flow-regulating device to control differential pressure in CSF shunt systems

1982 ◽  
Vol 57 (4) ◽  
pp. 570-573 ◽  
Author(s):  
Hiroshi Yamada
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Csf Shunt ◽  
Csf Flow ◽  
Csf Shunts ◽  
Shunt System ◽  
Distal Catheter ◽  
Content Type ◽  
Teflon Tube ◽  
Fine Print

✓ A method of regulating flow rate through cerebrospinal fluid (CSF) shunts with the addition of a flow-regulating device (FRD) is reported. The FRD consists of a small-caliber (0.4 mm) Teflon tube placed in the usual connector. This device has the advantage of converting the original shunt valves to valves for higher-resistance flow without replacing the entire distal catheter. An experimental study revealed that this device reduced the CSF flow rate in the shunt system by approximately 30%. The author has found it reliable in 32 patients, without causing CSF obstruction. The device is easily installed and removed.

Role of endoscopic third ventriculostomy at infected cerebrospinal fluid shunt removal

2012 ◽  
Vol 9 (3) ◽  
pp. 320-326 ◽  
Author(s):  
Tomohisa Shimizu ◽  
Mark G. Luciano ◽  
Toru Fukuhara
Keyword(s):  
Risk Factors ◽  
Cerebrospinal Fluid ◽  
Endoscopic Third Ventriculostomy ◽  
Shunt Infection ◽  
Secondary Outcome ◽  
Csf Shunt ◽  
Third Ventriculostomy ◽  
Cerebrospinal Fluid Shunt ◽  
Csf Shunts ◽  
Shunt Removal

Object Cerebrospinal fluid shunt infection is distressing, especially in the pediatric population. Usually, infected CSF shunts are removed, and after temporary external CSF drainage, reinsertion of the CSF shunt is necessary. Unfortunately, it is not rare to encounter CSF reinfection after shunt renewal, and furthermore, the reinserted CSF shunt is at a considerable risk of malfunction. Endoscopic third ventriculostomy (ETV) is a potent option in managing CSF shunt infection, although ETV failure may occur more frequently when it is used to remove an infected shunt. The authors retrospectively evaluated CSF reinfection after using ETV during removal of infected CSF shunts; then the longevity of ETV and of successive reinserted ventriculoperitoneal shunts (VPSs) after ETV failure were also examined. Methods Children with shunted hydrocephalus were retrospectively reviewed, and data on their initial CSF shunt infections were extracted. Thirty-six children underwent VPS reinsertion (the VPS group), and 9 underwent ETV after removal of the infected CSF shunt (the ETV group). As the primary outcome, ETV efficacy against CSF reinfection within 6 months was analyzed by comparing the reinfection rates, and the risk factors for CSF reinfection were analyzed by logistic regression. The longevity of the reinserted shunt in the VPS group was calculated using the Kaplan-Meier method, which was compared with ETV longevity as the secondary outcome, and also with the longevity of reinserted VPSs in the ETV group after ETV failure as the tertiary outcome. Results Reinfection of CSF was seen in 27.8% of children in the VPS group. Among 9 children in the ETV group, only 1 (11.1%) had CSF reinfection. However, logistic regression analysis failed to show that performing ETV was a significant factor protecting against CSF reinfection: the significant risk factors were younger age at reinsertion of VPS or ETV (p = 0.037) and a history of shunt revisions (p = 0.011). The longevity of reinserted VPSs in the VPS group was calculated to be 658 ± 166.3 days (mean ± SE). Longevity of ETV was compared in the analysis of the secondary outcome, which was 929.2 ± 511.1 days, and there were no significant differences between these durations. Only 2 ETVs stayed patent, and a VPS was eventually implanted in the other 7 children. The longevity of this reinserted VPS in the ETV group, calculated based on these 7 children, was 2011.1 ± 540.7 days, which was confirmed to be longer than that in the VPS group (p = 0.031). Conclusions Although the protective effect of using ETV during removal of an infected CSF shunt on reinfection is marginal, the ETV longevity can be considered equivalent to that of reinserted VPSs. Even if ETV failure occurs, the reinserted VPS has significantly better longevity than a VPS reinserted without using ETV, and use of ETV during infected CSF shunt removal can be considered a potent alternative or at least an adjunct to VPS reinsertion.

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