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Fernández Cornejo VJ, Elbabaa SK. Shunt technology for infants and a lifetime. Childs Nerv Syst 2021; 37:3475-3484. [PMID: 34240241 DOI: 10.1007/s00381-021-05132-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 03/15/2021] [Indexed: 11/24/2022]
Abstract
The use of cerebrospinal fluid (CSF) shunts remains a fundamental therapeutic modality in the management of hydrocephalus. Nowadays, neurosurgeons have an arsenal of different shunt technologies on their hands, with several companies producing many different configurations of them. The greatest difficulty of treating a child with hydrocephalus is to deal with a brain that will enormously change its size and hydrodynamic conditions and a body that will multiply its height and weight in a short time. Detailed knowledge of the hydrodynamic properties of shunts is mandatory for any neurosurgeon and much more for those taking care of pediatric patients. It is necessary to know that these properties of the valve may influence the evolution of the patient after shunting and it is recognized that a patient physiology-specific valve selection may yield better outcomes and decrease complications. This article provides a summary of the most common available CSF valves and overdrainage control devices, their technology, and possible combinations. The objective is to offer a quick overview of the armamentarium to facilitate the recognition of the implanted device and improve the selection of the most suitable valve for each patient.
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Affiliation(s)
- Víctor J Fernández Cornejo
- Sección de Neurocirugía Pediátrica. Servicio de Neurocirugia, Hospital General Universitario de Alicante, Alicante, Spain.
| | - Samer K Elbabaa
- Section of Pediatric and Fetal Neurosurgery, Orlando Health Arnold Palmer Hospital for Children, Orlando, FL, USA
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2
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Ros B, Iglesias S, Linares J, Cerro L, Casado J, Arráez MA. Shunt Overdrainage: Reappraisal of the Syndrome and Proposal for an Integrative Model. J Clin Med 2021; 10:jcm10163620. [PMID: 34441916 PMCID: PMC8396927 DOI: 10.3390/jcm10163620] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/05/2021] [Accepted: 08/12/2021] [Indexed: 11/16/2022] Open
Abstract
Although shunt overdrainage is a well-known complication in hydrocephalus management, the problem has been underestimated. Current literature suggests that the topic requires more examination. An insight into this condition is limited by a lack of universally agreed-upon diagnostic criteria, heterogeneity of published series, the multitude of different management options and misunderstanding of relationships among pathophysiological mechanisms involved. We carried out a review of the literature on clinical, radiological, intracranial pressure (ICP), pathophysiological and treatment concepts to finally propose an integrative model. Active prophylaxis and management are proposed according to this model based on determination of pathophysiological mechanisms and predisposing factors behind each individual case. As pathophysiology is progressively multifactorial, prevention of siphoning with gravitational valves or antisiphon devices is mandatory to avoid or minimize further complications. Shunt optimization or transferal and neuroendoscopy may be recommended when ventricular collapse and cerebrospinal fluid isolation appear. Cranial expansion may be useful in congenital or acquired craniocerebral disproportion and shunting the subarachnoid space in communicating venous hydrocephalus and idiopathic intracranial hypertension.
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Affiliation(s)
- Bienvenido Ros
- Pediatric Neurosurgery Division, Department of Neurosurgery, Regional University Hospital, Avda. Carlos Haya s/n, 29010 Malaga, Spain;
- Correspondence:
| | - Sara Iglesias
- Pediatric Neurosurgery Division, Department of Neurosurgery, Regional University Hospital, Avda. Carlos Haya s/n, 29010 Malaga, Spain;
| | - Jorge Linares
- Department of Neurosurgery, Regional University Hospital, Avda. Carlos Haya s/n, 29010 Malaga, Spain; (J.L.); (L.C.); (J.C.); (M.A.A.)
| | - Laura Cerro
- Department of Neurosurgery, Regional University Hospital, Avda. Carlos Haya s/n, 29010 Malaga, Spain; (J.L.); (L.C.); (J.C.); (M.A.A.)
| | - Julia Casado
- Department of Neurosurgery, Regional University Hospital, Avda. Carlos Haya s/n, 29010 Malaga, Spain; (J.L.); (L.C.); (J.C.); (M.A.A.)
| | - Miguel Angel Arráez
- Department of Neurosurgery, Regional University Hospital, Avda. Carlos Haya s/n, 29010 Malaga, Spain; (J.L.); (L.C.); (J.C.); (M.A.A.)
- Department of Surgery, Malaga University, 29010 Malaga, Spain
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Bettag C, von der Brelie C, Freimann FB, Thomale UW, Rohde V, Fiss I. In vitro testing of explanted shunt valves in hydrocephalic patients with suspected valve malfunction. Neurosurg Rev 2021; 45:571-583. [PMID: 34027574 PMCID: PMC8827297 DOI: 10.1007/s10143-021-01564-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 04/22/2021] [Accepted: 05/04/2021] [Indexed: 10/26/2022]
Abstract
Diagnosis of symptomatic valve malfunction in hydrocephalic patients treated with VP-Shunt (VPS) might be difficult. Clinical symptoms such as headache or nausea are nonspecific, hence cerebrospinal fluid (CSF) over- or underdrainage can only be suspected but not proven. Knowledge concerning valve malfunction is still limited. We aim to provide data on the flow characteristics of explanted shunt valves in patients with suspected valve malfunction. An in vitro shunt laboratory setup was used to analyze the explanted valves under conditions similar to those in an implanted VPS. The differential pressure (DP) of the valve was adjusted stepwise to 20, 10, 6, and 4 cmH2O. The flow rate of the explanted and the regular flow rate of an identical reference valve were evaluated at the respective DPs. Twelve valves of different types (Codman CertasPlus valve n = 3, Miethke Shuntassistant valve n = 4, Codman Hakim programmable valve n = 3, DP component of Miethke proGAV 2.0 valve n = 2) from eight hydrocephalic patients (four male), in whom valve malfunction was assumed between 2016 and 2017, were replaced with a new valve. Four patients suffered from idiopathic normal pressure (iNPH), three patients from malresorptive and one patient from obstructive hydrocephalus. Post-hoc analysis revealed a significant difference (p < 0.001) of the flow rate between each explanted valve and their corresponding reference valve, at each DP. In all patients, significant alterations of flow rates were demonstrated, verifying a valve malfunction, which could not be objectified by the diagnostic tools used in the clinical routine. In cases with obscure clinical VPS insufficiency, valve deficiency should be considered.
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Affiliation(s)
- Christoph Bettag
- Department of Neurosurgery, Georg-August-Universität Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany.
| | - Christian von der Brelie
- Department of Neurosurgery, Georg-August-Universität Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Florian Baptist Freimann
- Department of Neurosurgery, Georg-August-Universität Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Ulrich-Wilhelm Thomale
- Pediatric Neurosurgery, Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany
| | - Veit Rohde
- Department of Neurosurgery, Georg-August-Universität Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Ingo Fiss
- Department of Neurosurgery, Georg-August-Universität Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
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Sunderland GJ, Jenkinson MD, Conroy EJ, Gamble C, Mallucci CL. Neurosurgical CSF Diversion in Idiopathic Intracranial Hypertension: A Narrative Review. Life (Basel) 2021; 11:393. [PMID: 33925996 PMCID: PMC8146765 DOI: 10.3390/life11050393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 11/16/2022] Open
Abstract
The prevalence of idiopathic intracranial hypertension (IIH), a complex disorder, is increasing globally in association with obesity. The IIH syndrome occurs as the result of elevated intracranial pressure, which can cause permanent visual impairment and loss if not adequately managed. CSF diversion via ventriculoperitoneal and lumboperitoneal shunts is a well-established strategy to protect vision in medically refractory cases. Success of CSF diversion is compromised by high rates of complication; including over-drainage, obstruction, and infection. This review outlines currently used techniques and technologies in the management of IIH. Neurosurgical CSF diversion is a vital component of the multidisciplinary management of IIH.
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Affiliation(s)
- Geraint J. Sunderland
- Department of Paediatric Neurosurgery, Alder Hey Children’s Hospital NHS Foundation Trust, Liverpool L12 2AP, UK;
- Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool L9 7LJ, UK;
| | - Michael D. Jenkinson
- Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool L9 7LJ, UK;
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7BE, UK
| | - Elizabeth J. Conroy
- Liverpool Clinical Trials Centre, University of Liverpool, Liverpool, L69 3GL, UK; (E.J.C.); (C.G.)
| | - Carrol Gamble
- Liverpool Clinical Trials Centre, University of Liverpool, Liverpool, L69 3GL, UK; (E.J.C.); (C.G.)
| | - Conor L. Mallucci
- Department of Paediatric Neurosurgery, Alder Hey Children’s Hospital NHS Foundation Trust, Liverpool L12 2AP, UK;
- Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7TX, UK
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Gutowski P, Gölz L, Rot S, Lemcke J, Thomale UW. Gravitational shunt valves in hydrocephalus to challenge the sequelae of over-drainage. Expert Rev Med Devices 2020; 17:1155-1168. [PMID: 33176494 DOI: 10.1080/17434440.2020.1837622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION In hydrocephalus treatment, ventriculo-peritoneal shunts (VPS) have become the most relevant therapy for seven decades among other treatment options. Due to the hydrostatic pressure in vertical position, CSF diversion is somehow non-physiological. The integration of gravitational valves in VPS was established to counteract the hydrostatic draining force and to approach a physiological condition of the cerebrospinal diverting system. Numerous clinical studies have shown that gravitational valves are able to reduce secondary complications of VPS treatment. It remains a challenge for the treating neurosurgeon to select the correct valve resistance based on individual anatomies and different etiologies of hydrocephalus as well as varying levels of activity of the patient. AREAS COVERED This review covers the development of gravitational shunt valves from historical, theoretical and clinical aspects for pediatric and adult etiologies of hydrocephalus. We discuss the role of gravitational shunt valves in preventing over-drainage issues and present the state-of-the-art literature. Furthermore, ongoing prospective trials are presented. EXPERT OPINION Counteracting the hydrostatic force by selecting the correct valve in a VPS system to achieve physiological balance in CSF diversion during vertical and horizontal body changes has become the current standard for hydrocephalus management. Gravitational shunt valves reliably address this need to minimize over-drainage events in the vertical position without affecting the CSF flow in the horizontal position. The results of ongoing prospective studies on the safety and efficacy of adjustable gravitational valves are still pending. Due to the complexity of the CSF flow, lifelong follow-up care for patients with VPS is critical.
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Affiliation(s)
- Paweł Gutowski
- Department of Neurosurgery, Unfallkrankenhaus Berlin , Berlin, Germany.,Department of Neurosurgery, Bródno Mazovia Hospital , Warsaw, Poland
| | - Leonie Gölz
- Institute of Radiology and Neuroradiology, Unfallkrankenhaus , Berlin, Germany
| | - Sergej Rot
- Department of Neurosurgery, Unfallkrankenhaus Berlin , Berlin, Germany
| | - Johannes Lemcke
- Department of Neurosurgery, Unfallkrankenhaus Berlin , Berlin, Germany
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Fiss I, Röhrig P, Hore N, von der Brelie C, Bettag C, Freimann FB, Thomale UW, Rohde V, Brandner S. In vitro performance of six combinations of adjustable differential pressure valves and fixed anti-siphon devices with and without vertical motion. Acta Neurochir (Wien) 2020; 162:2421-2430. [PMID: 32779025 DOI: 10.1007/s00701-020-04519-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/30/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Adjustable differential pressure (DP) valves in combination with fixed anti-siphon devices are currently a popular combination in counteracting the effects of cerebrospinal fluid overdrainage following implantation of a ventriculoperitoneal shunt system. The study examined the flow performance of three DP valves in successive combination with an anti-siphon device in an in vitro shunt laboratory with and without vertical motion. METHODS We analyzed three DP valves (Codman Hakim Medos programmable valve [HM], Codman CertasPlus [CP], and Miethke proGAV [PG], in combination with either Codman SiphonGuard [SG] or Miethke ShuntAssistant [SA]), resulting in the evaluation of six different valve combinations. Defined DP conditions between 4 and 40 cm H2O within a simulated shunt system were generated and the specific flow characteristics were measured. In addition, combinations with SA, which is a gravity-dependent valve, were measured in defined spatial positions (90°, 60°). All device combinations were tested during vertical motion with movement frequencies of 2, 3, and 4 Hz. RESULTS All valve combinations effectively counteracted the siphon effect in relation to the chosen DP. Angulation-related flow changes were similar in the three combinations of DP valve and SA in the 60° and 90° position. In CP-SA and PG-SA, repeated vertical movement at 2, 3, and 4 Hz led to significant increase in flow, whereas in HM-SA, constant increase was seen at 4 Hz only (flow change at 4Hz, DP 40 cm H2O: PG (opening pressure 4 cm H2O) 90°: 0.95 ml/min, 60°: 0.71 ml/min; HM (opening pressure 4 cm H2O) 90°: 0.66 ml/min, 60°: 0.41 ml/min; CP (PL 2) 90°: 0.94 ml/min, 60°: 0.79 ml/min; p < 0.01); however, HM-SA showed relevant motion-induced flow already at low DPs (0.85 ml/min, DP 4 cm H2O). In combinations of DP valve with SG, increase of flow was far less pronounced and even led to significant reduction of flow in certain constellations. Maximum overall flow increase was 0.46 ± 0.04 ml/min with a HM (opening pressure 12 cm H2O) at 2 Hz and a DP of 10 cm H2O, whereas maximum flow decrease was 1.12 ± 0.08 with a PG (opening pressure 4 cm H2O) at 3 Hz and a DP of 10 cmH2O. CONCLUSION In an experimental setup, all valve combinations effectively counteracted the siphon effect in the vertical position according to their added resistance. Motion-induced increased flow was consistently demonstrated in combinations of DP valve and SA. The combination of HM and SA especially showed relevant motion-induced flow already at low DPs. In combinations of DP and SG, the pattern of the motion induced flow was more inconsistent and motion even led to significant flow reduction, predominantly at DPs of 10 and 20 cmH2O.
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Affiliation(s)
- I Fiss
- Department of Neurosurgery, University Hospital Göttingen, Göttingen, Germany.
- Department of Neurosurgery, Universitätsmedizin Göttingen, Georg-August University Göttingen, 37099, Göttingen, Germany.
| | - P Röhrig
- Department of Neurosurgery, University Hospital Göttingen, Göttingen, Germany
| | - N Hore
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
| | - C von der Brelie
- Department of Neurosurgery, University Hospital Göttingen, Göttingen, Germany
| | - C Bettag
- Department of Neurosurgery, University Hospital Göttingen, Göttingen, Germany
| | - F B Freimann
- Department of Neurosurgery, University Hospital Göttingen, Göttingen, Germany
| | - U-W Thomale
- Department of Paediatric Neurosurgery, Charité University Hospital, Berlin, Germany
| | - V Rohde
- Department of Neurosurgery, University Hospital Göttingen, Göttingen, Germany
| | - S Brandner
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
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Fiss I, Vanderheyden M, von der Brelie C, Bettag C, Hore N, Freimann F, Thomale UW, Rohde V, Brandner S. In vitro performance of combinations of anti-siphon devices with differential pressure valves in relation to the spatial position. Acta Neurochir (Wien) 2020; 162:1033-1040. [PMID: 31997071 DOI: 10.1007/s00701-020-04228-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/13/2020] [Indexed: 12/01/2022]
Abstract
BACKGROUND Programmable differential pressure (DP) valves combined with an anti-siphon device (ASD) represent the current standard of care in preemtping overdrainage associated with ventriculoperitoneal shunting for hydrocephalus. OBJECTIVE We aimed to provide comparative data of four combinations of two ASDs of different working principles in combination with two DP valves in an in vitro model in order to achieve a better understanding of the flow characteristics and potential clinical application. METHODS We analyzed the flow performance of four possible combinations of two DP valves (CHPV [HM]; proGAV 2.0[PG]) in combination with either a gravity-regulated (Shuntassistant [SA]) or a flow-regulated (SiphonGuard [SG]) ASD in an in vitro setup. A DP between 4 and 60 cmH2O was generated, and the specific flow characteristics were measured. In addition, the two combinations with gravity-regulated ASDs were measured in defined spatial positions. RESULTS Flow characteristics of the SA combinations corresponded to the DP in linear fashion and to the spatial position. Flow characteristics of the SG combinations were dependent upon the DP in a non-linear fashion and independent of the spatial position. Highest mean flow rate of the PG-SG- (HM-SG-) combination was 1.41 ± 0.24 ml/min (1.16 ± 0.06 ml/min). The mean flow rates sharply decreased with increasing inflow pressure and subsequently increased slowly up to 0.82 ± 0.26 ml/min (0.77 ± 0.08 ml/min). CONCLUSION All tested device combinations were able to control hydrostatic effect and prevent consecutive excessive flow, to varying degrees. However, significant differences in flow characteristics can be seen, which might be relevant for their clinical application.
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Affiliation(s)
- I Fiss
- Department of Neurosurgery, Universitätsmedizin Göttingen, Georg-August University Göttingen, 37099, Göttingen, Germany.
| | - M Vanderheyden
- Department of Neurosurgery, Universitätsmedizin Göttingen, Georg-August University Göttingen, 37099, Göttingen, Germany
| | - C von der Brelie
- Department of Neurosurgery, Universitätsmedizin Göttingen, Georg-August University Göttingen, 37099, Göttingen, Germany
| | - C Bettag
- Department of Neurosurgery, Universitätsmedizin Göttingen, Georg-August University Göttingen, 37099, Göttingen, Germany
| | - N Hore
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
| | - F Freimann
- Department of Neurosurgery, Universitätsmedizin Göttingen, Georg-August University Göttingen, 37099, Göttingen, Germany
| | - U-W Thomale
- Department of Paediatric Neurosurgery, Charité University Hospital, Berlin, Germany
| | - V Rohde
- Department of Neurosurgery, Universitätsmedizin Göttingen, Georg-August University Göttingen, 37099, Göttingen, Germany
| | - S Brandner
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
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Gehlen M, Eklund A, Kurtcuoglu V, Malm J, Schmid Daners M. Comparison of anti-siphon devices-how do they affect CSF dynamics in supine and upright posture? Acta Neurochir (Wien) 2017; 159:1389-1397. [PMID: 28660395 DOI: 10.1007/s00701-017-3249-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 06/07/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Three different types of anti-siphon devices (ASDs) have been developed to counteract siphoning-induced overdrainage in upright posture. However, it is not known how the different ASDs affect CSF dynamics under the complex pressure environment seen in clinic due to postural changes. We investigated which ASDs can avoid overdrainage in upright posture best without leading to CSF accumulation. METHODS Three shunts each of the types Codman Hakim with SiphonGuard (flow-regulated), Miethke miniNAV with proSA (gravitational), and Medtronic Delta (membrane controlled) were tested. The shunts were compared on a novel in vitro setup that actively emulates the physiology of a shunted patient. This testing method allows determining the CSF drainage rates, resulting CSF volume, and intracranial pressure in the supine, sitting, and standing posture. RESULTS The flow-regulated ASDs avoided increased drainage by closing their primary flow path when drainage exceeded 1.39 ± 0.42 mL/min. However, with intraperitoneal pressure increased in standing posture, we observed reopening of the ASD in 3 out of 18 experiment repetitions. The adjustable gravitational ASDs allow independent opening pressures in horizontal and vertical orientation, but they did not provide constant drainage in upright posture (0.37 ± 0.03 mL/min and 0.26 ± 0.03 mL/min in sitting and standing posture, respectively). Consequently, adaptation to the individual patient is critical. The membrane-controlled ASDs stopped drainage in upright posture. This eliminates the risk of overdrainage, but leads to CSF accumulation up to the volume observed without shunting when the patient is upright. CONCLUSIONS While all tested ASDs reduced overdrainage, their actual performance will depend on a patient's specific needs because of the large variation in the way the ASDs influence CSF dynamics: while the flow-regulated shunts provide continuous drainage in upright posture, the gravitational ASDs allow and require additional adaptation, and the membrane-controlled ASDs show robust siphon prevention by a total stop of drainage.
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Affiliation(s)
- Manuel Gehlen
- Institute for Dynamic Systems and Control, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Vartan Kurtcuoglu
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Jan Malm
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Marianne Schmid Daners
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, CLA G 21.1, 8092, Zürich, Switzerland.
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Moghtader D, Crawack HJ, Miethke C, Dörlemann Z, Shellock FG. Assessment of MRI issues for a new cerebral spinal fluid shunt, gravitational valve (GV). Magn Reson Imaging 2017; 44:8-14. [PMID: 28735732 DOI: 10.1016/j.mri.2017.07.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/13/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE A gravitational valve (GV) may be used to treat hydrocephalus, offering possible advantages that include avoidance of over drainage and long-term complications. Because a GV is made from metal, there are potential safety and other problems related to the use of MRI. The objective of this investigation was to evaluate MRI-related issues (i.e., magnetic field interactions, heating, and artifacts) for a newly developed, metallic GV. METHODS Tests were performed on the GV (GAV 2.0) using well-accepted techniques to assess magnetic field interactions (translational attraction and torque, 3-Tesla), MRI-related heating (1.5-T/64-MH and 3-T/128-MHz, whole body averaged SAR, 2.7-W/kg and 2.9-W/kg, respectively), artifacts (3-Tesla; gradient echo and T1-weighted, spin echo sequences), and possible functional changes related to exposures to different MRI conditions (exposing six samples each to eight different pulse sequences at 1.5-T/64-MHz and 3-T/128-MHz). RESULTS Magnetic field interactions were not substantial (deflection angle 2°, no torque) and heating was minor (highest temperature rise, ≥1.9°C, highest background temperature rise, ≥1.7°C). Artifacts on the gradient echo pulse sequence extended approximately 10mm from the size and shape of the GV. The different exposures to 1.5-T/64-MHz and 3-T/128-MHz conditions did not alter or damage the operational aspects of the GV samples. CONCLUSIONS The findings demonstrated that MRI can be safely used in patients with this GV and, thus, this metallic implant is deemed acceptable or "MR Conditional" (i.e., using current labeling terminology), according to the conditions used in this study.
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Affiliation(s)
- Daniel Moghtader
- Department of Chemistry and Biochemistry, Loyola Marymount University, 1 Loyola Marymount University Dr., Los Angeles, CA 90045, United States
| | | | - Christoph Miethke
- Christoph Miethke GmBH & Co. KG, Ulanenweg 2, D-14469 Potsdam, Germany.
| | - Zinah Dörlemann
- Christoph Miethke GmBH & Co. KG, Ulanenweg 2, D-14469 Potsdam, Germany.
| | - Frank G Shellock
- Department of Radiology, Keck School of Medicine, University of Southern California, 7751 Veragua Dr., Playa Del Rey, CA 90293, United States; Department of Medicine, Keck School of Medicine, University of Southern California, 7751 Veragua Dr., Playa Del Rey, CA 90293, United States.
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10
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Bozhkov Y, Roessler K, Hore N, Buchfelder M, Brandner S. Neurological outcome and frequency of overdrainage in normal pressure hydrocephalus directly correlates with implanted ventriculo-peritoneal shunt valve type. Neurol Res 2017; 39:601-605. [DOI: 10.1080/01616412.2017.1321300] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Yavor Bozhkov
- Department of Neurosurgery, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Karl Roessler
- Department of Neurosurgery, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Nirjhar Hore
- Department of Neurosurgery, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Michael Buchfelder
- Department of Neurosurgery, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
| | - Sebastian Brandner
- Department of Neurosurgery, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Erlangen, Germany
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11
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In vitro performance of the fixed and adjustable gravity-assisted unit with and without motion-evidence of motion-induced flow. Acta Neurochir (Wien) 2016; 158:2011-8. [PMID: 27553048 DOI: 10.1007/s00701-016-2912-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/27/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Anti-siphon devices and gravitational-assisted valves have been introduced to counteract the effects of overdrainage after implantation of a shunt system. The study examined the flow performance of two gravitational-assisted valves (shunt assistant - SA and programmable shunt assistant - proSA, Miethke & Co. KG, Potsdam, Germany) in an in vitro shunt laboratory with and without motion. METHODS An in vitro laboratory setup was used to model the cerebrospinal fluid (CSF) drainage conditions similar to a ventriculo-peritoneal shunt and to test the SA (resistance of +20 cmH2O in 90°) and proSA (adjustable resistance of 0 to +40 cmH2O in 90°). The differential pressure (DP) through the simulated shunt and tested valve was adjusted between 0 and 60 cmH2O by combinations of different inflow pressures (40, 30, 20, 10, and 0 cmH2O) and the hydrostatic negative outflow pressure (0, -20, and -40 cmH2O) in several differing device positions (0°, 30°, 60°, and 90°). In addition, the two devices were tested under vertical motion with movement frequencies of 2, 3, and 4 Hz. RESULTS Both gravity-assisted units effectively counteract the hydrostatic effect in relation to the chosen differential pressure. The setting the proSA resulted in flow reductions in the 90° position according to the chosen resistance of the device. Angulation-related flow changes were similar in the two devices in 30-90° position, however, in the 0-30° position, a higher flow is seen in the proSA. Repeated vertical movement significantly increased flow through both devices. While with the proSA a 2-Hz motion was not able to induce additional flow (0.006 ± 0.05 ml/min), 3- and 4-Hz motion significantly induced higher flow values (3 Hz: +0.56 ± 0.12 ml/min, 4 Hz: +0.54 ± 0.04 ml/min). The flow through the SA was not induced by vertical movements at a low DP of 10 cmH2O at all frequencies, but at DPs of 30 cmH2O and higher, all frequencies significantly induced higher flow values (2 Hz: +0.36 ± 0.14 ml/min, 3 Hz: +0.32 ± 0.08 ml/min, 4 Hz: +0.28 ± 0.09 ml/min). CONCLUSIONS In a static setup, both tested valves effectively counteracted the hydrostatic effect according to their adjusted or predefined resistance in vertical position. Motion-induced increased flow was demonstrated for both devices with different patterns of flow depending on applied DP and setting of the respective valve. The documented increased drainage should be considered when selecting appropriate valves and settings in very active patients.
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Diesner N, Freimann F, Clajus C, Kallenberg K, Rohde V, Stockhammer F. Female gender predisposes for cerebrospinal fluid overdrainage in ventriculoperitoneal shunting. Acta Neurochir (Wien) 2016; 158:1273-8. [PMID: 27177735 DOI: 10.1007/s00701-016-2827-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Gravitational valves (GVs) prevent overdrainage in ventriculoperitoneal shunting (VPS). However, there are no data available on the appropriate opening pressure in the shunt system when implementing a GV. We performed a retrospective analysis of hydrocephalic patients who were successfully treated with VPS which included one or more GV. METHOD In this retrospective study in adult VPS patients with GVs, we analysed all available data, including the most recent computed tomography (CT) scans, to determine the best adjustments for alleviating any symptoms of overdrainage and underdrainage. Vertical effective opening pressure (VEOP) of the entire shunt system, including the differential pressure valve, was determined. RESULTS One hundred and twenty-two patients were eligible for the study. Of these, female patients revealed a higher VEOP compared with males (mean, 35.6 cmH2O [SD ± 2.46] vs 28.9 cmH2O [SD ± 0.87], respectively, p = 0.0072, t-test). In patients older than 60 years, lower VEOPs, by a mean of 6.76 cmH2O ± 2.37 (p = 0.0051), were necessary. Mean VEOP was found to be high in idiopathic intracranial hypertension (IIH; 41.6 cmH2O) and malresorptive and congenital HC (35.9 and 36.3), but low in normal pressure HC (27.5, p = 0.0229; one-way ANOVA). In the total cohort, body mass index (BMI) and height did not correlate with VEOP. Twelve patients required a VEOP of more than 40 cmH2O, and in eight of these patients this was accomplished by using multiple GVs. All but one of these eight patients were of female gender, and none of the latter were treated for normal pressure hydrocephalus (NPH) (p = 0.0044 and p = 0.0032, Fisher's exact test). CONCLUSIONS In adult VPS patients, female gender increases the risk of overdrainage requiring higher VEOPs. Initial implantation of adjustable GV should be considered in female patients treated with VP shunts for pathology other than NPH.
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Gehlen M, Kurtcuoglu V, Daners MS. Patient Specific Hardware-in-the-Loop Testing of Cerebrospinal Fluid Shunt Systems. IEEE Trans Biomed Eng 2016. [DOI: 10.1109/tbme.2015.2457681] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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