Ventricular Catheter Obstruction Research Articles

Ventricular catheter tissue obstruction and shunt malfunction in 9 hydrocephalus etiologies.

Hydrocephalus is a neurological disorder with an incidence of 80-125 per 100,000 births in the United States. The most common treatment, ventricular shunting, has a failure rate of up to 85% within 10 years of placement. The authors aimed to analyze the association between ventricular catheter (VC) tissue obstructions and shunt malfunction for each hydrocephalus etiology. Patient information was collected from 5 hospitals and entered into a REDCap (Research Electronic Data Capture) database by hydrocephalus etiology. The hardware samples were fixed, and each VC tip drainage hole was classified by tissue obstruction after macroscopic analysis. Shunt malfunction data, including shunt revision rate, time to failure, and age at surgery, were correlated with the degree of tissue obstruction in VCs for each etiology. Posthemorrhagic hydrocephalus was the most common etiology (48.9% of total cases). Proximal catheter obstruction was the most frequent cause of hardware removal (90.4%). Myelomeningocele (44% ± 29%), other congenital etiologies (48% ± 40%), hydrocephalus with brain tumors (45% ± 35%), and posthemorrhagic hydrocephalus (41% ± 35%) showed tissue aggregates in more than 40% of the VC holes. A total of 76.8% of samples removed because of symptoms of obstruction showed cellular or tissue aggregates. No conclusive etiological associations were detected when correlating the percentage of holes with tissue for each VC and age at surgery, shunt revision rates, or time between shunt implantation and removal. The proximal VC obstruction was accompanied by tissue aggregates in 76.8% of cases. However, the presence of tissue in the VC did not seem to be associated with hydrocephalus etiology.

Reduction of cell surface attachment in experimental hydrocephalus using a novel ventricular catheter with modified tethered liquid perfluorocarbon.

Ventriculoperitoneal shunting, the most common treatment for the neurological disorder hydrocephalus, has a failure rate of up to 98% within 10 years of placement, mainly because of proximal obstruction of the ventricular catheter (VC). The authors developed a new VC design modified with tethered liquid perfluorocarbon (TLP) and tested it in a porcine model of hydrocephalus. In this study, they aimed to determine if their TLP VC design reduced cell surface attachment and consequent shunt obstruction in the pig model. TLP VCs were designed to reduce drainage hole obstruction using modified TLP and slightly enlarged draining holes, but their number and placement remained very similar to standard VCs. First, the authors tested the device in nonhydrocephalic rats to assess biocompatibility. After confirming safety, they implanted the VCs in hydrocephalic pigs. Hydrocephalus was induced by intracisternal kaolin injections in 30-day-old domestic juvenile pigs. Surgical implantation of the ventriculoperitoneal shunt (clinical control or TLP) was performed 10-14 days postinduction and maintained up to 30 days posttreatment. MRI was performed to measure ventricular volume before treatment and 10 and 30 days after treatment. Histological and immunohistochemical analyses of brain tissue and explanted VCs, intracranial pressure measurement, and clinical scoring were performed when the animals were euthanized. TLP VCs showed a similar surgical feel, kink resistance, and stiffness to control VCs. In rats (biocompatibility assessment), TLP VCs did not show brain inflammatory reactions after 30 or 60 days of implantation. In pigs, TLP VCs demonstrated increased survival time, improved clinical outcome scores, and significantly reduced total attached cells on the VCs compared with standard clinical control VCs. TLP VCs exhibited similar, but not worse, results related to ventriculomegaly, intracranial pressure, and the local tissue response around the cortical shunt track in pigs. TLP VCs may be a strong candidate to reduce proximal VC obstruction and improve hydrocephalus treatment.

Use of a Prophylactic Retrograde-Flushing Device in High-Risk Pediatric Patients with Ventriculoperitoneal Shunts: A Technical Note

Introduction: Ventriculoperitoneal shunt (VPS) malfunction rates are as high as 40% in the first year with posthemorrhagic hydrocephalus (PHH) patients having the highest proximal occlusion risk. Debris, protein, and cellular ingrowth most commonly obstruct the proximal ventricular catheter and/or valve. Historically, no preventative methods have demonstrated efficacy. We present a technical note and case series describing the use of a retrograde proximal flushing device and prophylactic flushing protocol to maintain ventricular catheter patency and reduce proximal shunt occlusions. Methods: We present our 2.8–4-year follow-up data on the first 9 pediatric cases of ReFlow (Anuncia Inc, Scottsdale, AZ) device implantation combined with routine prophylactic flushing. Rationale for device implantation, patient selection, surgical procedure details, postoperative follow-up, and prophylactic flushing protocol are discussed as well as pre- and postimplantation ventricular catheter obstruction rates. We include a technical note on the device setup and prophylactic flushing protocol. Results: Patient average age was 5.6 years and all patients had PHH. Minimal follow-up was 2.8 years (range 2.8–4 years). Prophylactic flushing was initiated between 2 and 14 days after ReFlow implantation and has continued as of the last follow-up. In 7 patients, ReFlow implantation occurred during the revision of an existing shunt and in two, implantation was coincident with initial VPS placement. In the 2 years preceding ReFlow and prophylactic flushing, 14 proximal shunt failures occurred in the 7 patients with existing VPS. This was reduced to only one proximal shunt failure in all 9 patients during the full follow-up period after ReFlow and prophylactic flushing. Conclusion: Pediatric VPS placement carries high rates of proximal catheter occlusion, often leading to emergency surgery, morbidity, or even death. The ReFlow device along with routine prophylactic flushing may reduce proximal obstruction and need for revision surgery. Higher patient numbers and longer follow-up periods are necessary to further elucidate the safety and effect of such a device on longer term shunt failures and revision surgery.

Long-Term Complications and Treatment in Patients with Ventriculo-Peritoneal Shunt Surgery

The purpose of treatment hydrocephalus is to maintain intracranial pressure, as well as to create a favorable psychomotor developmental environment, particularly in pediatric cases. Various complications associated with shunt surgery require long-term care. When a shunt is performed for neonates and infants with hydrocephalus, proper management is required thereafter during whole their life. The most common complication that can occur as a result of shunt surgery is obstruction of the ventricular catheter. Ventricular catheter obstruction can be avoided by placing that the tip of the catheter is placed in an appropriate position. A further measure would include preventing the ventricular catheter from being pulled out as the skull expands. The next common complication is obstruction of the peritoneal catheter. The risk of occlusion can be reduced by making that the tip of the peritoneal catheter is open-ended as opposed to having side slits. Isolated ventricles and slit ventricle syndrome are peculiar shunt-related conditions that are difficult to treat. When shunt dysfunction occurs, hydrocephalus can progress slowly, but in many cases the patient's condition deteriorates rapidly and requires immediate medical intervention. Recently, neuroendoscopic surgery has been actively performed for cases of shunt dysfunction and prophylactic replacement of peritoneal catheters, and attempts have been made to remove the shunt device. Shunt infection is another troublesome complication in the management of hydrocephalus and has not yet been resolved. However, if all staff involved in shunt surgery have a common understanding and adopt fixed protocols related to preoperative, intraoperative, and postoperative management, the incidence of infection can be significantly reduced. Furthermore, the development of new and improved catheters may also contribute to a reduction in shunt infection. Neurosurgeons should be cognizant that a delay in the diagnosis and treatment of shunt-related complications in patients with hydrocephalus could result in death. Shunt surgery for the treatment of pediatric hydrocephalus is merely the beginning, as neurosurgeons must be responsible for management until the child reaches adulthood.

Fluidic Considerations of Measuring Intracranial Pressure Using an Open External Ventricular Drain.

Measurement of intracranial pressure (ICP) during cerebrospinal fluid (CSF) drainage with an external ventricular drain (EVD) typically requires stopping the flow during measurement. However, there may be benefits to simultaneous ICP measurement and CSF drainage. Several studies have evaluated whether accurate ICP measurements can be obtained while the EVD is open. They report differing outcomes when it comes to error, and hypothesize several sources of error. This study presents an investigation into the fluidic sources of error for ICP measurement with concurrent drainage in an EVD.Our experiments and analytical model both show that the error in pressure measurement increases linearly with flow rate and is not clinically significant, regardless of drip chamber height. At physiologically relevant flow rates (40 mL/hr) and ICP set points (13.6 - 31.3 cmH2O or 10 - 23 mmHg), our model predicts an underestimation of 0.767 cmH2O (0.56 mmHg) with no observed data point showing error greater than 1.09 cmH2O (0.8 mmHg) in our experiment. We extrapolate our model to predict a realistic worst-case clinical scenario where we expect to see a mean maximum error of 1.06 cmH2O (0.78 mmHg) arising from fluidic effects within the drainage system for the most resistive catheter.Compared to other sources of error in current ICP monitoring, error in pressure measurement due to drainage flow is small and does not prohibit clinical use. However, other effects such as ventricular collapse or catheter obstruction could affect ICP measurement under continuous drainage and are not investigated in this study.

Shunt malfunction and endoscopy

Objective: 
 Hydrocephalus is the most common neurological disease in pediatric neurosurgery.(1) The CSF shunts remains as the most common treatment choice for nonobstructive hydrocephalus worldwide, but shunt complications still the most common neurosurgical problem, especially in pediatric neurosurgery. Endoscopy and shunts are the way to treat hydrocephalus. Especially third ventriculostomy is the most effective treatment to obstructive hydrocephalus but shunt still the most important way to treat.(2, 3) Shunt malfunction is frequent and after so many years this is very important problem to the patients. Ventricular problem due to obstruction is responsible up to 72% of shunt problems.(4) The Shunt Trial Study showed that the overall shunt survival was 62% at 1 year, 52% at 2 years, 46% at 3 years, 41% at 4 years. The survival curves for the 3 differents valves were similar to those from the original trial and did not show a survival advantage for any particular valve.(5, 6) We still don´t have one perfect solution to hydrocephalus and shunt malfunction.
 The major author described his experience in use endoscopy to evaluate and treat shunt malfunction and one new approach and way to evaluate this problem.
 
 Results/Discussion:
 The literature review was performed, and we found 84 articles when we used the keywords. Endoscopy has been one important way to treat and solve shunt problems. In obstructive hydrocephalus third ventriculostomy is the best way to treat these patients.(1-3)
 The major author first described goals of endoscopy. First goal is safe catheter removal in surgical review, avoiding bleeding when removing catheter addressing all the adhesions on catheter. Second goal is put in optimal position the new catheter with pure endoscopy view or using neuronavigation systems that could help the endoscope system.(7, 8) 
 Optimal new catheter placement and optimal long-term catheter survival are especially important because most of the problems are due to ventricular problems. These good placements could avoid loculations and ventricular collapse with ependymal problems. Avoid new catheter malpositiitioning, you can use the endoscope to follow the old tract to insert the new catheter in one good position avoiding choroid plexus. Another situation is when you have small ventricles especially in slit ventricle syndrome.
 
 The major author has been studied some causes to ventricular catheter obstruction. He noticed after some surgical reviews some ventricular ependymal inside catheter. Ventricular ependymal protrusions inside the catheter could cause intermittent occlusion.(8) Some endoscope views showed these protrusion and ependymal changes after intermittent increase and decrease of ventricular pressure. These protrusions correspond to catheter holes a secondary to suction. These protrusions could stuck in the holes in chronicle suction.(8) The major author reported one endoscopic evidence of overdrainage-related ventricular tissue protrusions that cause partial or complete obstruction of the ventricular catheter. He did a retrospective review in fifty patients underwent 83 endoscopic shunt revision procedures that revealed in-growth of ventricular wall tissue into the catheter tip orifices (ependymal bands), producing partial, complete, or intermittent shunt obstructions. Endoscopic ventricular explorations revealed ependymal bands at various stages of development, which appear to form secondarily to siphoning.(8)
 How to minimize this overshunting? Anti siphon systems could help and decrease proximal shunt malfunction in some complex patients. The other problem is ventricular bleeding. The use of endoscope has been important tool to remove ventricular catheters, when you could see the adhesions.(9)
 The use the endoscope could be particularly important to open loculations and cysts avoiding ventricular entrapment. Patients with ventricular cysts could need more than one catheter. The use of endoscopy to fenestrate the cyst could keep the patient with one catheter or without any shunt system.(10, 11)
 
 Conclusion:
 Shunt malfunction has a lot of possible causes, but a probably ventricular catheter problem is the most common situation. Choose appropriate endoscope rigid or flexible for each case could help to treat and avoid some of ventricular. Endoscopy could be one important tool to help the surgeon to understand and solve this dangerous situation to the patient. Ventricular wall protrusions are a significant cause of proximal shunt obstruction, and they appear to be caused by siphoning of surrounding tissue into the ventricular catheter orifices.

A 12-year single-center retrospective analysis of antisiphon devices to prevent proximal ventricular shunt obstruction for hydrocephalus.

Recent evidence points to gravity-dependent chronic shunt overdrainage as a significant, if not leading, cause of proximal shunt failure. Yet, shunt overdrainage or siphoning persists despite innovations in valve technology. The authors examined the effectiveness of adding resistance to flow in shunt systems via antisiphon devices (ASDs) in preventing proximal shunt obstruction. A retrospective observational cohort study was completed on patients who had an ASD (or additional valve) added to their shunt system between 2004 and 2016. Detailed clinical, radiographic, and surgical findings were examined. Shunt failure rates were compared before and after ASD addition. Seventy-eight patients with shunted hydrocephalus were treated with placement of an ASD several centimeters distal to the primary valve. The records of 12 of these patients were analyzed separately due to a complex shunt revision history (i.e., > 10 lifetime shunt revisions). The authors found that adding an ASD decreased the 1-year ventricular catheter obstruction rates in the "simple" and "complex" groups by 67.3% and 75.8%, respectively, and the 5-year rates by 43.3% and 65.6%, respectively. The main long-term ASD complication was ASD removal for presumed valve pressure intolerance in 5 patients. Using an ASD may result in significant reductions in ventricular catheter shunt obstruction rates. If confirmed with prospective studies, this observation would lend further evidence that chronic shunt overdrainage is a central cause of shunt malfunction, and provide pilot data to establish clinical and laboratory studies that assess optimal ASD type, number, and position, and eventually develop shunt valve systems that are altogether resistant to siphoning.

Endoluminal Shuntscope-Guided Ventricular Catheter Placement: Early Experience.

Background:Placement of ventricular catheter (VC) in an optimal position is the most important factor in determining the outcome of shunt surgery. VC obstruction due to shunt tube placement in brain parenchyma, across the septa, tangled in the choroid plexuses and clogging of VC due to brain matter or other debris are common reasons resulting in shunt complete or partial dysfunction. To resolve these hurdles, many technical advancements have been made including navigation, stereotaxy, sonography, and ventriculoscope-guided VC placement.Objective:To report early experience, technique, and result of placing VC with shuntscope.Methods:We are publishing our experience of shuntscope-guided ventriculoperitoneal shunt in 9 cases done from June 2015 to April 2016. Shuntscope is a 1 mm outer diameter semi-rigid scope from Karl Storz with 10000 pixel of magnification. It has a fiber optic lens system with camera and light source attachment away from the scope to make it light weight and easily maneuverable.Results:In all cases, VC was placed in the ipsilateral frontal horn away from choroid plexuses, septae, or membranes. Septum pellucidum perforation and placement to opposite side of ventricle was identified with shunt scope assistance and corrected.Conclusion:Although our initial results are encouraging, larger case series would be helpful. Complications and cost due to shunt dysfunction can thus be reduced to a great extent with shuntscope.

Overdrainage-related ependymal bands: a postulated cause of proximal shunt obstruction.

OBJECTIVEVentricular shunts have an unacceptably high failure rate, which approaches 50% of patients at 2 years. Most shunt failures are related to ventricular catheter obstruction. The literature suggests that obstructions are caused by in-growth of choroid plexus and/or reactive cellular aggregation. The authors report endoscopic evidence of overdrainage-related ventricular tissue protrusions ("ependymal bands") that cause partial or complete obstruction of the ventricular catheter.METHODSA retrospective review was completed on patients undergoing shunt revision surgery between 2008 and 2015, identifying all cases in which the senior author reported endoscopic evidence of ependymal tissue in-growth into ventricular catheters. Detailed clinical, radiological, and surgical findings are described.RESULTSFifty patients underwent 83 endoscopic shunt revision procedures that revealed in-growth of ventricular wall tissue into the catheter tip orifices (ependymal bands), producing partial, complete, or intermittent shunt obstructions. Endoscopic ventricular explorations revealed ependymal bands at various stages of development, which appear to form secondarily to siphoning. Ependymal bands are associated with small ventricles when the shunt is functional, but may dilate at the time of obstruction.CONCLUSIONSVentricular wall protrusions are a significant cause of proximal shunt obstruction, and they appear to be caused by siphoning of surrounding tissue into the ventricular catheter orifices.

Ultrasound-guided placement of ventricular catheters in first-time pediatric VP shunt surgery.

Ventriculo-peritoneal (VP) shunts are effective for treatment of hydrocephalus in all age groups; however, they are associated with complications, a common one being ventricular catheter (VC) obstruction. VC position is likely to influence VC survival; however, most VCs are positioned freehand without guidance. This paper describes the accuracy of ultrasound guidance for VC placement and the impact of tip location on VC occlusion rate. This is a retrospective cohort study of hydrocephalic children with first-time VP shunt and ultrasound-guided VC placement. Data recorded were age, sex, cause of hydrocephalus, side (left or right) and location (frontal or occipital) of VC, and exact postoperative position within the ventricle on first postoperative imaging: middle of ventricle (optimal position), near or touching the medial or lateral ventricle wall, within the third ventricle, and at the contralateral side. Of the 128 screened patients, 85 had a first postoperative imaging that clearly defined the VC position and were included. The follow-up was at least 12months. Seventy-three percent of VCs were placed on the right and 71% via a frontal burhole. Eighty-three of 85 VC tips (95%) were in the intended ventricle, 61% at optimal position. Nine of 85 VCs (10%) obstructed within the first 12months. Seven of nine (78%) obstructed VCs were located in a nonoptimal position (p = 0.016). Two of nine (22%) obstructed VCs entered through a frontal and seven of nine (78%) through an occipital burrhole (p = 0.016). Ultrasound-guided VC placement is as precise as frameless navigated placement. The optimal VC position was associated to a significant lower VC obstruction rate. The frontal position was superior to the occipital. Intraoperative US guidance is fast with almost no extra time and no extra cost. US-guided VC placement should become standard of care in VP shunt surgery.

Shunt-dependent hydrocephalus: management style among members of the American Society of Pediatric Neurosurgeons.

OBJECTIVE The authors conducted a survey to evaluate differences in the understanding and management of shunt-dependent hydrocephalus among members of the American Society of Pediatric Neurosurgeons (ASPN). METHODS Surveys were sent to all 204 active ASPN members in September 2014. One hundred thirty responses were received, representing a 64% response rate. Respondents were asked 13 multiple-choice and free-response questions regarding 4 fundamental problems encountered in shunted-hydrocephalus management: shunt malfunction, chronic cerebrospinal fluid (CSF) overdrainage, chronic headaches, and slit ventricle syndrome (SVS). RESULTS Respondents agreed that shunt malfunction occurs most often as the result of ventricular catheter obstruction. Despite contrary evidence in the literature, most respondents (66%) also believed that choroid plexus is the tissue most often found in obstructed proximal catheters. However, free-text responses revealed that the respondents' understanding of the underlying pathophysiology of shunt obstruction was highly variable and included growth, migration, or adherence of choroid plexus, CSF debris, catheter position, inflammatory processes, and CSF overdrainage. Most respondents considered chronic CSF overdrainage to be a rare complication of shunting in their practice and reported wide variation in treatment protocols. Moreover, despite a lack of evidence in the literature, most respondents attributed chronic headaches in shunt patients to medical reasons (for example, migraines, tension). Accordingly, most respondents managed headaches with reassurance and/or referral to pain clinics. Lastly, there were variable opinions on the etiology of slit ventricle syndrome (SVS), which included early shunting, chronic overdrainage, and/or loss of brain compliance. Beyond shunt revision, respondents reported divergent SVS treatment preferences. CONCLUSIONS The survey shows that there is wide variability in the understanding and management of shunt-dependent hydrocephalus and its complications. Such discrepancies appear to be derived partly from inconsistent familiarity with existing literature but especially from a paucity of high-quality publications.

Toward a better understanding of the cellular basis for cerebrospinal fluid shunt obstruction: report on the construction of a bank of explanted hydrocephalus devices.

OBJECTIVE Shunt obstruction by cells and/or tissue is the most common cause of shunt failure. Ventricular catheter obstruction alone accounts for more than 50% of shunt failures in pediatric patients. The authors sought to systematically collect explanted ventricular catheters from the Seattle Children's Hospital with a focus on elucidating the cellular mechanisms underlying obstruction. METHODS In the operating room, explanted hardware was placed in 4% paraformaldehyde. Weekly, samples were transferred to buffer solution and stored at 4°C. After consent was obtained for their use, catheters were labeled using cell-specific markers for astrocytes (glial fibrillary acidic protein), microglia (ionized calcium-binding adapter molecule 1), and choroid plexus (transthyretin) in conjunction with a nuclear stain (Hoechst). Catheters were mounted in custom polycarbonate imaging chambers. Three-dimensional, multispectral, spinning-disk confocal microscopy was used to image catheter cerebrospinal fluid-intake holes (10× objective, 499.2-μm-thick z-stack, 2.4-μm step size, Olympus IX81 inverted microscope with motorized stage and charge-coupled device camera). Values are reported as the mean ± standard error of the mean and were compared using a 2-tailed Mann-Whitney U-test. Significance was defined at p < 0.05. RESULTS Thirty-six ventricular catheters have been imaged to date, resulting in the following observations: 1) Astrocytes and microglia are the dominant cell types bound directly to catheter surfaces; 2) cellular binding to catheters is ubiquitous even if no grossly visible tissue is apparent; and 3) immunohistochemical techniques are of limited utility when a catheter has been exposed to Bugbee wire electrocautery. Statistical analysis of 24 catheters was performed, after excluding 7 catheters exposed to Bugbee wire cautery, 3 that were poorly fixed, and 2 that demonstrated pronounced autofluorescence. This analysis revealed that catheters with a microglia-dominant cellular response tended to be implanted for shorter durations (24.7 ± 6.7 days) than those with an astrocyte-dominant response (1183 ± 642 days; p = 0.027). CONCLUSIONS Ventricular catheter occlusion remains a significant source of shunt morbidity in the pediatric population, and given their ability to intimately associate with catheter surfaces, astrocytes and microglia appear to be critical to this pathophysiology. Microglia tend to be the dominant cell type on catheters implanted for less than 2 months, while astrocytes tend to be the most prevalent cell type on catheters implanted for longer time courses and are noted to serve as an interface for the secondary attachment of ependymal cells and choroid plexus.

Ventricular catheter development: past, present, and future.

Cerebrospinal fluid diversion via ventricular shunting is the prevailing contemporary treatment for hydrocephalus. The CSF shunt appeared in its current form in the 1950s, and modern CSF shunts are the result of 6 decades of significant progress in neurosurgery and biomedical engineering. However, despite revolutionary advances in material science, computational design optimization, manufacturing, and sensors, the ventricular catheter (VC) component of CSF shunts today remains largely unchanged in its functionality and capabilities from its original design, even though VC obstruction remains a primary cause of shunt failure. The objective of this paper is to investigate the history of VCs, including successful and failed alterations in mechanical design and material composition, to better understand the challenges that hinder development of a more effective design.

Hidrocefalijos revizinių operacijų priežastys

Darbo tikslasNustatyti pacientų, sergančių hidrocefalija, pakartotinių operacijų dažnį ir priežastis. Įvertinti šunto revizijos poreikio bei vožtuvo gedimo dažnio priklausomybę nuo hidrocefalijos etiologijos, likvoro priešoperacinio slėgio, implantuoto vožtuvo gamintojo bei drenuoto smegenų skilvelio rago.Ligoniai ir metodaiRetrospektyviai išanalizuoti operacijų protokolai bei epikrizės visų 130 pacientų, kuriems nuo 2007 m. vasario 1 d. iki 2014 m. sausio 31 d. VšĮ Respublikinės Vilniaus universitetinės ligoninės (RVUL) Neurochirurgijos skyriuje atlikta 214 ventrikuloperitoneostomijos (VPS) operacijų dėl hidrocefalijos (HC). Rinkti duomenys: HC etiologija, likvoro slėgis prieš operaciją, operacijų skaičius, pakartotinių operacijų priežastys, drenuotas ragas, implantuotas vožtuvas bei nustatytas vožtuvo atsidarymo slėgis. Tarpusavyje lyginant pacientus pagal implantuotus skirtingų gamintojų vožtuvus, HC priežastis ir likvoro slėgį prieš operaciją, ieškota statistiškai patikimų koreliacijų su vožtuvo gedimo ir revizijos poreikio dažniu. Duomenys statistiškai apdoroti SPSS 22.0 programa.RezultataiPasiskirstymas pagal lytį: 49 % vyrų, 51 % moterų. Amžius svyravo nuo 20 iki 83 metų, amžiaus vidurkis 55±15,0 metų. 55 metų amžiaus arba jaunesni buvo 61 (46,9 %) pacientas, vyresni nei 55 metų – 69 (53,1 %) pacientai. Aptariamuoju laikotarpiu atlikta 214 VPS operacijų. Vieną kartą operuoti 84 (64,6 %) pacientai, pakartotinai – 46 (35,4 %) pacientai, kai kurie po keletą kartų. Nustatytos pakartotinės operacijos priežastys – galvinio kateterio užsikimšimas konstatuotas 2,17 % atvejų, vožtuvo gedimas – 30,43 % atvejų, pilvinio kateterio užsikimšimas – 10,87 %, mišrus šunto sistemos blokas – 23,92 %, šunto migracija – 10,87 %, sistemos šalinimas dėl infekcijos – 19,57 %, tiksli priežastis nenustatyta – 2,17 %. Dažniausia pakartotinės operacijos priežastis – vožtuvo gedimas. Tarpusavyje lyginant implantuotų skirtingų gamintojų vožtuvų – „Codman“, „Sophysa“, „Medtronic“ – gedimo dažnį, statistiškai reikšmingo skirtumo nerasta (p&gt;0,05). Taip pat vožtuvo gedimo dažnis nesiskyrė drenavus priekinį ar užpakalinį ragą (p&gt;0,05). Tačiau 55 metų amžiaus ir jaunesniems pacientams šunto revizijos reikėjo dažniau nei vyresniems (p=0,047). Be to, vožtuvas gedo gerokai dažniau, kai likvoro slėgis prieš operaciją buvo žemas, palyginti su vidutiniu (p=0,035) ir aukštu (p=0,036) likvoro slėgiu prieš operaciją. Nustatyta patikima atvirkštinė koreliacija – likvoro takų stenozės atveju vožtuvas genda daug rečiau nei esant kitoms HC priežastims (p=0,012).IšvadosPakartotinės VPS operacijos prireikė 35,4 % pacientų. Dažniausia pakartotinės operacijos priežastis – vožtuvo gedimas. Pacientų amžius pirmosios operacijos metu, HC etiologija, likvoro slėgis prieš operaciją reikšmingai susiję su vožtuvo gedimo dažniu ir revizijos poreikio dažniu. Vožtuvo gedimo dažnis ir šunto revizijos poreikis nepriklauso nuo implantuoto šunto gamintojo ir drenuoto rago.

Towards a better understanding of the cellular basis for cerebrospinal fluid shunt obstruction: report on construction of a bank of explanted hydrocephalus devices

OBJECTIVE Shunt obstruction by cells and/or tissue is the most common cause of shunt failure. Ventricular catheter obstruction alone accounts for more than 50% of shunt failures in pediatric patients. The authors sought to systematically collect explanted ventricular catheters from the Seattle Children's Hospital with a focus on elucidating the cellular mechanisms underlying obstruction. METHODS In the operating room, explanted hardware was placed in 4% paraformaldehyde. Weekly, samples were transferred to buffer solution and stored at 4°C. After consent was obtained for their use, catheters were labeled using cell-specific markers for astrocytes (glial fibrillary acidic protein), microglia (ionized calcium-binding adapter molecule 1), and choroid plexus (transthyretin) in conjunction with a nuclear stain (Hoechst). Catheters were mounted in custom polycarbonate imaging chambers. Three-dimensional, multispectral, spinning-disk confocal microscopy was used to image catheter cerebrospinal fluid–intake holes...

Computational fluid dynamics of ventricular catheters used for the treatment of hydrocephalus: a 3D analysis

The most common treatment for hydrocephalus remains the ventriculoperitoneal shunt. Yet, the most frequent complication is ventricular catheter obstruction, which may account for 50-80% of newly inserted shunts. Although many factors contribute to this, the main one is related to flow characteristics of the catheter within the hydrocephalic brain. A landmark study by Lin et al. addressed the problem of fluid characteristics in ventricular catheters using a two-dimensional simulation program of computational fluid dynamics (CFD). The authors have studied five current commercially available ventricular catheter designs using CFD in three-dimensional automated designs. The general procedure for the development of a CFD model involves incorporating the physical dimensions of the system to be studied into a virtual wire-frame model. The shape and features of the actual physical model are transformed into coordinates for the virtual space of the computer and a CFD computational grid (mesh) is generated. The fluid properties and motion are calculated at each of these grid points. After grid generation, flow field boundary conditions are applied, and the fluid's thermodynamic and transport properties are included. At the end, a system of strongly coupled, nonlinear, partial differential conservation equations governing the motion of the flow field are numerically solved. This numerical solution describes the fluid motion and properties. The authors calculated that most of the total fluid mass flows into the catheter's most proximal holes. Fifty to 75% flows into the two most proximal sets of inlets of current commercially available 12-32-hole catheters. Some flow uniformity was disclosed in Rivulet-type catheter. Most commercially available ventricular catheters have an abnormally increase flow distribution pattern. New catheter designs with variable hole diameters along the catheter tip will allow the fluid to enter the catheter more uniformly along its length, thereby reducing the probability of its becoming occluded.

Shunt survival after failed endoscopic treatment of hydrocephalus

It is not known whether previous endoscopic third ventriculostomy (ETV) affects the risk of shunt failure. Different epochs of hydrocephalus treatment at the CURE Children's Hospital of Uganda (CCHU)-initially placing CSF shunts in all patients, then attempting ETV in all patients, and finally attempting ETV combined with choroid plexus cauterization (CPC) in all patients-provided the opportunity to assess whether prior endoscopic surgery affected shunt survival. With appropriate institutional approvals, the authors reviewed the CCHU clinical database to identify 2329 patients treated for hydrocephalus from December 2000 to May 2007. Initial ventriculoperitoneal (VP) shunt placement was performed in 900 patients under one of three circumstances: 1) primary nonselective VP shunt placement with no endoscopy (255 patients); 2) VP shunt placement at the time of abandoned ETV attempt (with or without CPC) (370 patients); 3) VP shunt placement subsequent to a completed but failed ETV (with or without CPC) (275 patients). We analyzed time to shunt failure using the Kaplan-Meier method to construct survival curves, Cox proportional hazards regression modeling, and risk-adjusted analyses to account for possible confounding differences among these groups. Shunt failure occurred in 299 patients, and the mean duration of follow-up for the remaining 601 was 28.7 months (median 18.8, interquartile range 4.1-46.3). There was no significant difference in operative mortality (p = 0.07 by log-rank and p = 0.14 by Cox regression adjusted for age and hydrocephalus etiology) or shunt infection (p = 0.94, log-rank) among the 3 groups. There was no difference in shunt survival between patients treated with primary shunt placement and those who underwent shunt placement at the time of an abandoned ETV attempt (adjusted hazard ratio [HR] 1.14, 95% CI 0.86-1.51, p = 0.35). Those who underwent shunt placement after a completed but failed ETV (with or without CPC) had a lower risk of shunt failure (p = 0.008, log-rank), with a hazard ratio (adjusted for age at shunting and etiology) of 0.72 (95% CI 0.53-0.98), p = 0.03, compared with those who underwent primary shunt placement without endoscopy; but this was observed only in patients with postinfectious hydrocephalus (PIH) (adjusted HR 0.55, 95% CI 0.36-0.85, p = 0.007), and no effect was apparent for hydrocephalus of noninfectious etiologies (adjusted HR 0.98, 95% CI 0.64-1.50, p = 0.92). Improved shunt survival after failed ETV in the PIH group may be an artifact of selection arising from the inherent heterogeneity of ventricular damage within that group, or a consequence of the timing of shunt placement. The anticipated benefit of CPC in preventing future ventricular catheter obstruction was not observed. A paradigm for infant hydrocephalus involving intention to treat by ETV with or without CPC had no adverse effect on mortality or on subsequent shunt survival or infection risk. This study failed to demonstrate a positive effect of prior ETV or CPC on shunt survival.

What We Should Know About the Cellular and Tissue Response Causing Catheter Obstruction in the Treatment of Hydrocephalus

The treatment of hydrocephalus by cerebrospinal fluid shunting is plagued by ventricular catheter obstruction. Shunts can become obstructed by cells originating from tissue normal to the brain or by pathological cells in the cerebrospinal fluid for a variety of reasons. In this review, the authors examine ventricular catheter obstruction and identify some of the modifications to the ventricular catheter that may alter the mechanical and chemical cues involved in obstruction, including alterations to the surgical strategy, modifications to the chemical surface of the catheter, and changes to the catheter architecture. It is likely a combination of catheter modifications that will improve the treatment of hydrocephalus by prolonging the life of ventricular catheters to improve patient outcome.

Ventricular catheter exchange using a peel-away outer catheter

Ventricular catheter replacement can be challenging, especially in patients with small ventricles. Shunt malfunction due to ventricular catheter obstruction can occur without ventricular enlargement, such as in the setting of slit-ventricle syndrome or benign intracranial hypertension. The authors describe a simple technique for ventricular catheter exchange using a peel-away catheter. In the limited initial experience of the senior author (G.S.C.), this technique appears to be safe and effective. To the authors' knowledge, this method has not been described in the neurosurgical literature before.

Can using a peel-away sheath in shunt implantation prevent ventricular catheter obstruction?

Shunt obstruction is the most common shunt complication. In 2003, Kehler et al. used peel-away sheath while implanting the ventricular catheter in 20 patients. They found less revision rate in the peel-away sheath group. We aimed to test the efficacy of this technique in cadavers. We used 100 fresh brains obtained from medicolegal autopsies. Posterior parietal and frontal approaches were used to puncture the lateral ventricle in each cerebral hemisphere. The ventricle is punctured with a peel-away sheath system. After the ventricle is reached, the mandarin is retracted and the ventricular catheter is introduced through the opening. The ventricular catheter was removed from the ventricle, the opening at the tip of the ventricular catheter was checked out for obstruction, and the number of patent and plugged openings was recorded. This procedure was repeated four times for each location with and without using peel-away sheath. The control group consisted of the procedures done without using peel-away sheath. The number of the plugged openings in the peel-away sheath group was significantly smaller than the control group. There was no significant difference between the two groups in terms of gender and left and right cerebral hemispheres. The obstruction rate was significantly lower in the posterior parietal approach. Pearson's correlation showed that increasing age was associated with less obstruction rate. Peel-away sheath decreases the number of plugged openings of the ventricular catheter. A clinical cooperative study is needed to prove that a peel-away sheath should be included in the ventricular shunt systems in the market.