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Podgoršak A, Flürenbrock F, Trimmel NE, Korn L, Oertel MF, Stieglitz L, Fernandes Dias S, Hierweger MM, Zeilinger M, Weisskopf M, Schmid Daners M. Toward the "Perfect" Shunt: Historical Vignette, Current Efforts, and Future Directions. Adv Tech Stand Neurosurg 2024; 50:1-30. [PMID: 38592526 DOI: 10.1007/978-3-031-53578-9_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
As a concept, drainage of excess fluid volume in the cranium has been around for more than 1000 years. Starting with the original decompression-trepanation of Abulcasis to modern programmable shunt systems, to other nonshunt-based treatments such as endoscopic third ventriculostomy and choroid plexus cauterization, we have come far as a field. However, there are still fundamental limitations that shunts have yet to overcome: namely posture-induced over- and underdrainage, the continual need for valve opening pressure especially in pediatric cases, and the failure to reinstall physiologic intracranial pressure dynamics. However, there are groups worldwide, in the clinic, in industry, and in academia, that are trying to ameliorate the current state of the technology within hydrocephalus treatment. This chapter aims to provide a historical overview of hydrocephalus, current challenges in shunt design, what members of the community have done and continue to do to address these challenges, and finally, a definition of the "perfect" shunt is provided and how the authors are working toward it.
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Affiliation(s)
- Anthony Podgoršak
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Fabian Flürenbrock
- Institute for Dynamic Systems and Control, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Nina Eva Trimmel
- Center for Preclinical Development, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Leonie Korn
- Institute for Dynamic Systems and Control, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Markus Florian Oertel
- Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Lennart Stieglitz
- Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Sandra Fernandes Dias
- Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Melanie Michaela Hierweger
- Center for Preclinical Development, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Melanie Zeilinger
- Institute for Dynamic Systems and Control, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Miriam Weisskopf
- Center for Preclinical Development, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Marianne Schmid Daners
- Institute for Dynamic Systems and Control, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland.
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Keadwut K, Lewchalermwong P, Inpithuk N, Choochalermporn P, Pongpradit A, Koatsang N, Suwanna N. Evaluation of Overshunting between Low and Medium Pressure Ventriculoperitoneal Shunts in Dogs with Severe Hydrocephalus Using Frameless Stereotactic Ventricular Shunt Placement. Animals (Basel) 2023; 13:1890. [PMID: 37370401 DOI: 10.3390/ani13121890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/29/2023] Open
Abstract
Hydrocephalus is a neurological disorder characterized by an abnormal accumulation of cerebrospinal fluid (CSF) within the ventricular system of the brain, leading to cerebral ventricular dilation, brain parenchyma compression, and neuronal cell loss. Surgery is an effective method of draining excessive amounts of CSF. Ventriculoperitoneal shunt (VPS) allows excess CSF to divert into the abdomen; this device is the most commonly used in the treatment of hydrocephalus both in veterinary and human patients. This study aims to describe the application of two types of VPS, low-pressure valve and medium-pressure valve, using a frameless stereotactic neuronavigational system in eight severe hydrocephalus in dogs and, in particular, analyze the prevalence of postoperative overshunting. Non-communicating hydrocephalus was found in seven dogs, whereas the rest of them had communicating hydrocephalus caused by traumatic brain injury with a skull fracture. The criteria for pressure valve selection depended on the intraoperative intraventricular pressure (IVP) that was determined by the adaptive manometer, according to the human protocol. Low-pressure valve placement was performed in five dogs, and the others received medium-pressure valve placement. The follow-up period was 2 weeks, 4-12 weeks, and 12 weeks to 12 months. Pre- and postoperative information including neurological signs, CT-Scan or MRI, medical treatment, complications, and ventricular volume were compared in all dogs. Seven dogs showed neurological improvement within 2 weeks after surgery. Overshunting was seen in four dogs who received low-pressure valve placement. Three of them had shunt infections within 4 to 6 weeks after surgery. One dog underwent shunt revision from a low-pressure valve to a medium-pressure valve caused by severe overshunting and progressive neurological signs. In addition, cognitive and learning improvements were evaluated based on the owners' feedback, and neurological signs were examined during the follow-up period in two dogs that received low-pressure valve placement. We conclude that a medium-pressure valve is recommended for overshunting prevention. However, low-pressure valve placement seems to improve cognitive function and learning ability, which is related to an increase in the brain parenchyma observed during long-term monitoring. Moreover, we also report our experience and surgical procedure for frameless stereotactic ventricular shunt placement (FSVSP) in VPS surgery in dogs affected by hydrocephalus.
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Affiliation(s)
- Kanokwan Keadwut
- Kasetsart University Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Pakthorn Lewchalermwong
- Kasetsart University Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Nathanat Inpithuk
- Kasetsart University Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Piyathip Choochalermporn
- Kasetsart University Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Ananya Pongpradit
- Kasetsart University Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Nattika Koatsang
- Kasetsart University Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
| | - Nirut Suwanna
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand
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Trimmel NE, Podgoršak A, Oertel MF, Jucker S, Arras M, Schmid Daners M, Weisskopf M. The Sheep as a Comprehensive Animal Model to Investigate Interdependent Physiological Pressure Propagation and Multiparameter Influence on Cerebrospinal Fluid Dynamics. Front Neurosci 2022; 16:868567. [PMID: 35431780 PMCID: PMC9008349 DOI: 10.3389/fnins.2022.868567] [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: 02/02/2022] [Accepted: 03/09/2022] [Indexed: 11/18/2022] Open
Abstract
The present study aims to develop a suitable animal model for evaluating the physiological interactions between cerebrospinal fluid (CSF) dynamics, hemodynamics, and abdominal compartment pressures. We seek to contribute to the enhanced recognition of the pathophysiology of CSF-dependent neurological disorders like hydrocephalus and the improvement of available treatment options. To date, no comprehensive animal model of CSF dynamics exists, and establishing an accurate model will advance our understanding of complex CSF physiology. Persisting knowledge gaps surrounding the communication and pressure propagation between the cerebrospinal space and adjacent anatomical compartments exacerbate the development of novel therapies for neurological diseases. Hence, the need for further investigation of the interactions of vascular, craniospinal, and abdominal pressures remains beyond dispute. Moreover, the results of this animal study support the optimization of in vitro test benches for medical device development, e.g., ventriculoperitoneal shunts. Six female white alpine sheep were surgically equipped with pressure sensors to investigate the physiological values of intracranial, intrathecal, arterial, central venous, jugular venous, vesical pressure, and four differently located abdominal pressures. These values were measured simultaneously during the acute animal trial with sheep under general anesthesia. Both carotid and femoral arterial blood pressure indicate a reliable and comparable representation of the systematic blood pressure. However, the jugular venous pressure and the central venous pressure in sheep in dorsal recumbency do not correlate well under general anesthesia. Furthermore, there is a trend for possible comparability of lateral intraventricular and lumbar intrathecal pressure. Nevertheless, animal body position during measurements must be considered since different body constitutions can alter the horizontal line between the cerebral ventricles and the lumbar subarachnoid space. While intra-abdominal pressure measurement in the four different abdominal quadrants yielded greater inter-individual variability, intra-vesical pressure measurements in our setting delivered comparable values for all sheep. We established a novel and comprehensive ovine animal model to investigate interdependent physiologic pressure propagation and multiparameter influences on CSF dynamics. The results of this study will contribute to further in vitro bench testing, the derivation of novel quantitative models, and the development of a pathologic ovine hydrocephalus model.
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Affiliation(s)
- Nina Eva Trimmel
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Anthony Podgoršak
- Department of Mechanical and Process Engineering, ETH Zürich, Zurich, Switzerland
| | - Markus Florian Oertel
- Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Simone Jucker
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Margarete Arras
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | - Miriam Weisskopf
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Iyer RR, Gorelick N, Carroll K, Blitz AM, Beck S, Garrett CM, Monroe A, Tyler B, Zuckerman ST, Capadona JR, von Recum HA, Luciano MG. Evaluation of an in vivo model for ventricular shunt infection: a pilot study using a novel antimicrobial-loaded polymer. J Neurosurg 2019; 131:587-595. [PMID: 30074457 PMCID: PMC6677638 DOI: 10.3171/2018.1.jns172523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/15/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Ventricular shunt infection remains an issue leading to high patient morbidity and cost, warranting further investigation. The authors sought to create an animal model of shunt infection that could be used to evaluate possible catheter modifications and innovations. METHODS Three dogs underwent bilateral ventricular catheter implantation and inoculation with methicillin-sensitive Staphylococcus aureus (S. aureus). In 2 experimental animals, the catheters were modified with a polymer containing chemical "pockets" loaded with vancomycin. In 1 control animal, the catheters were polymer coated but without antibiotics. Animals were monitored for 9 to 11 days, after which the shunts were explanted. MRI was performed after shunt implantation and prior to catheter harvest. The catheters were sonicated prior to microbiological culture and also evaluated by electron microscopy. The animals' brains were evaluated for histopathology. RESULTS All animals underwent successful catheter implantation. The animals developed superficial wound infections, but no neurological deficits. Imaging demonstrated ventriculitis and cerebral edema. Harvested catheters from the control animal demonstrated > 104 colony-forming units (CFUs) of S. aureus. In the first experimental animal, one shunt demonstrated > 104 CFUs of S. aureus, but the other demonstrated no growth. In the second experimental animal, one catheter demonstrated no growth, and the other grew trace S. aureus. Brain histopathology revealed acute inflammation and ventriculitis in all animals, which was more severe in the control. CONCLUSIONS The authors evaluated an animal model of ventricular shunting and reliably induced features of shunt infection that could be microbiologically quantified. With this model, investigation of pathophysiological and imaging correlates of infection and potentially beneficial shunt catheter modifications is possible.
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Affiliation(s)
- Rajiv R. Iyer
- Departments of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Noah Gorelick
- Departments of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Karen Carroll
- Departments of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ari M. Blitz
- Departments of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sarah Beck
- Departments of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Caroline M. Garrett
- Departments of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Audrey Monroe
- Departments of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Betty Tyler
- Departments of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sean T. Zuckerman
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland
| | - Jeffrey R. Capadona
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland
- Departments Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio
| | - Horst A. von Recum
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland
| | - Mark G. Luciano
- Departments of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Hazer DB, Mut M, Dinçer N, Saribas Z, Hazer B, Ozgen T. The efficacy of silver-embedded polypropylene-grafted polyethylene glycol-coated ventricular catheters on prevention of shunt catheter infection in rats. Childs Nerv Syst 2012; 28:839-46. [PMID: 22373811 DOI: 10.1007/s00381-012-1729-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Accepted: 02/15/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE Catheter-related infection is a major complication of ventriculoperitoneal shunt in children. The aim of this study is to determine inflammatory response and the efficacy of polypropylene-grafted polyethylene glycol (PP-g-PEG) copolymer and silver nanoparticle-embedded PP-g-PEG (Ag-PP-g-PEG) polymer-coated ventricular catheters on the prevention of catheter-related infections on a new experimental model of ventriculoperitoneal shunt in rats. METHODS Thirty six Wistar albino rats were divided into six groups: group 1, unprocessed sterile silicone catheter-embedded group; group 2, sterile PP-g-PEG-coated catheter group; group 3, sterile Ag-PP-g-PEG-coated catheter group; group 4, infected unprocessed catheter group; group 5, infected PP-g-PEG-coated catheter group; and group 6, infected Ag-PP-g-PEG-coated catheter group, respectively. In all groups, 1-cm piece of designated catheters were placed into the cisterna magna. In groups 4, 5, and 6, all rats were infected with 0.2 mL of 10 × 10(6) colony forming units (CFU)/mL Staphylococcus epidermidis colonies before the catheters were placed. Thirty days after implantation, bacterial colonization in cerebrospinal fluid and on catheter pieces with inflammatory reaction in the brain parenchyma was analyzed quantitatively. RESULTS Sterile and infected Ag-PP-g-PEG-covered groups revealed significantly lower bacteria colony count on the catheter surface (ANOVA, 0 ± 0, p < 0.001; 1.08 ± 0.18, p < 0.05, respectively). There was moderate inflammatory response in the parenchyma in group 4, but in groups 5 and 6, it was similar to that of the sterile group (ANOVA, 16.33 ± 3.02, p < 0.001; 4.00 ± 0.68, p < 0.001, respectively). CONCLUSIONS The PP-g-PEG, especially Ag-PP-g-PEG polymer-coated ventricular catheters are more effective in preventing the catheter-related infection and created the least inflammatory reaction in the periventricular parenchyma.
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Affiliation(s)
- Derya Burcu Hazer
- Department of Neurosurgery, Muğla University Faculty of Medicine, Muğla, Turkey.
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Kobayashi H, Oethinger M, Tuohy MJ, Hall GS, Bauer TW. Distinction between intact and antibiotic-inactivated bacteria by real-time PCR after treatment with propidium monoazide. J Orthop Res 2010; 28:1245-51. [PMID: 20186836 DOI: 10.1002/jor.21108] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
One limitation to the use of the polymerase chain reaction (PCR) to identify orthopedic infections has been apparent false-positive results, possibly due to the detection of dead bacteria. We recently showed that the use of DNA-binding agent propidium monoazide (PMA) could distinguish viable from heat-inactivated bacteria, and, in this study, we investigated whether the same technique can be applied to bacteria killed by two antibiotics with distinctly different mechanisms of action, a test of greater clinical relevance than thermal inactivation. Staphylococcus aureus and S. epidermidis were inactivated by vancomycin and gentamicin and treated with PMA or left untreated before DNA extraction. The threshold cycle difference of antibiotic-treated bacteria with and without PMA pretreatment was investigated with PCR primers for the 16S rDNA and tuf genes. Our results indicated that PMA effectively inhibited detection by PCR of bacteria, which had been inactivated by either vancomycin or gentamicin. The effect was statistically significant at 24 h after treatment (C(t) difference consistently >3; p < 0.05) and after 10 days of treatment (C(t) difference >4; p < 0.01), when compared to viable cells (C(t) difference 1-2). Vancomycin had a stronger effect on the C(t) value than gentamicin, reflecting the different mechanism of action of each antibiotic. Techniques of this type may help reduce clinically false-positive PCR results caused by the detection of dead bacteria, and may be especially useful in patients who have received antibiotics, such as patients undergoing the second stage of a two-stage revision for infected arthroplasty.
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Affiliation(s)
- Hideo Kobayashi
- Department of Anatomic Pathology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio, USA
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Park EH, Dombrowski S, Luciano M, Zurakowski D, Madsen JR. Alterations of pulsation absorber characteristics in experimental hydrocephalus. J Neurosurg Pediatr 2010; 6:159-70. [PMID: 20672938 DOI: 10.3171/2010.5.peds09142] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Analysis of waveform data in previous studies suggests that the pulsatile movement of CSF may play a role in attenuating strong arterial pulsations entering the cranium, and its effectiveness in attenuating these pulsations may be altered by changes in intracranial pressure (ICP). These findings were obtained in studies performed in canines with normal anatomy of the CSF spaces. How then would pulsation absorbance respond to changes in CSF movement under obstructive conditions such as the development of hydrocephalus? In the present study, chronic obstructive hydrocephalus was induced by the injection of cyanoacrylate gel into the fourth ventricle of canines, and pulsation absorbance was compared before and after hydrocephalus induction. METHODS Five animals were evaluated with simultaneous recordings of ICP and arterial blood pressure (ABP) before and at 4 and 12 weeks after fourth ventricle obstruction by cyanoacrylate. To assess how the intracranial system responds to the arterial pulsatile component, ABP and ICP waveforms recorded in a time domain had to be analyzed in a frequency domain. In an earlier study the authors introduced a particular technique that allows characterization of the intracranial system in the frequency domain with sufficient accuracy and efficiency. This same method was used to analyze the relationship between ABP and ICP waveforms recorded during several acute states including hyperventilation as well as CSF withdrawal and infusion under conditions before and after inducing chronic obstructive hydrocephalus. Such a relationship is reflected in terms of a gain, which is a function of frequency. The cardiac pulsation absorbance (CPA) index, which is simply derived from a gain evaluated at the cardiac frequency, was used to quantitatively evaluate the changes in pulsation absorber function associated with the development of hydrocephalus within each of the animals, which did become hydrocephalic. To account for normal and hydrocephalic conditions within the same animal and at multiple time points, statistical analysis was performed by repeated-measures ANOVA. RESULTS The performance of the pulsation absorber as assessed by CPA significantly deteriorated after the development of chronic hydrocephalus. In these animals the decrement in CPA was far more significant than other anticipated changes including those in ICP, compliance, or ICP pulse amplitude. CONCLUSIONS To the extent that the free CSF movement acts as a buffer of arterial pulsation input to flow in microvessels, alterations in the pulsation absorber may play a pathophysiological role. One measure of alterations in the way the brain deals with pulsatile input-the CPA measurement-changes dramatically with the imposition of hydrocephalus. Results in the present study suggest that CPA may serve as a complementary metric to the conventional static measure of intracranial compliance in other experimental and clinical studies.
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Affiliation(s)
- Eun-Hyoung Park
- Department of Neurosurgery, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts 02115, USA
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