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Holmlund P, Støverud KH, Eklund A. Mathematical modelling of the CSF system: effects of microstructures and posture on optic nerve subarachnoid space dynamics. Fluids Barriers CNS 2022; 19:67. [PMID: 36042452 PMCID: PMC9426285 DOI: 10.1186/s12987-022-00366-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/18/2022] [Indexed: 11/21/2022] Open
Abstract
Background The pressure difference between the eye and brain in upright postures may be affected by compartmentalization of the optic nerve subarachnoid space (ONSAS). Both pressure and deformation will depend on the microstructures of the ONSAS, and most likely also on ocular glymphatic clearance. Studying these factors could yield important knowledge regarding the translaminar pressure difference, which is suspected to play a role in normal-tension glaucoma. Methods A compartment model coupling the ONSAS with the craniospinal CSF system was used to investigate the effects of microstructures on the pressure transfer through the ONSAS during a posture change from supine to upright body postures. ONSAS distensibility was based on MRI measurements. We also included ocular glymphatic flow to investigate how local pressure gradients alter this flow with changes in posture. Results A compartmentalization of the ONSAS occurred in the upright posture, with ONSAS porosity (degree of microstructural content) affecting the ONSAS pressure (varying the supine/baseline porosity from 1.0 to 0.75 yielded pressures between − 5.3 and − 2 mmHg). Restricting the minimum computed porosity (occurring in upright postures) to 0.3 prevented compartmentalization, and the ONSAS pressure could equilibrate with subarachnoid space pressure (− 6.5 mmHg) in \documentclass[12pt]{minimal}
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\begin{document}$$\le$$\end{document}≤ 1 h. The ocular glymphatics analysis predicted that substantial intraocular-CSF flows could occur without substantial changes in the ONSAS pressure. The flow entering the ONSAS in supine position (both from the intraocular system and from the cranial subarachnoid space) exited the ONSAS through the optic nerve sheath, while in upright postures the flow through the ONSAS was redirected towards the cranial subarachnoid space. Conclusions Microstructures affect pressure transmission along the ONSAS, potentially contributing to ONSAS compartmentalization in upright postures. Different pathways for ocular glymphatic flow were predicted for different postures.
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Affiliation(s)
- Petter Holmlund
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, 901 87, Umeå, Sweden.
| | - Karen-Helene Støverud
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, 901 87, Umeå, Sweden.,Department of Health Research, SINTEF Digital, Trondheim, Norway
| | - Anders Eklund
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, 901 87, Umeå, Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, 901 87, Umeå, Sweden
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Hou Y, Liang H, Fan C, Liu R, Feng Y. Association of intraocular pressure and postoperative nausea and vomiting after microvascular decompression - a prospective cohort study. BMC Anesthesiol 2022; 22:132. [PMID: 35490219 PMCID: PMC9055703 DOI: 10.1186/s12871-022-01665-x] [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: 08/04/2021] [Accepted: 04/18/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Postoperative nausea and vomiting is common in patients receiving microvascular decompression. In the current study, we examined whether postoperative nausea and vomiting is associated with reduced intraocular pressure (IOP) after microvascular decompression, a measure that reflects intracranial pressure. METHODS This is a prospective cohort study. Adult patients scheduled for microvascular decompression surgery for hemifacial spasm between January 2020 and August 2020 were eligible. IOP was measured immediately before anesthesia induction and 30 min after patients regained complete consciousness using non-contact tonometry. IOP reduction was defined by at least 1 mmHg decrease vs. preoperative baseline. The primary outcome was vomiting on postoperative day 1. RESULTS A total of 103 subjects were enrolled. IOP was reduced in 56 (54.4%) subjects. A significantly greater proportion of patients with IOP reduction had vomiting on postoperative day 1 (51.8% (29/56) vs. 23.4% (11/47) in those without IOP reduction; p = 0.003). In the multivariate regression analysis, vomiting on postoperative day 1 was associated with female sex [odds ratio = 7.87, 95% CI: 2.35-26.32, p = 0.001] and IOP reduction [odds ratio = 2.93, 95% CI: 1.13-7.58, p = 0.027]. CONCLUSIONS In patients undergoing microvascular decompression surgery, postoperative IOP reduction is associated with postoperative vomiting. TRIAL REGISTRATION Chinese Clinical Trial Registry: ChiCTR2000029083 . Registered 13 January 2020.
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Affiliation(s)
- Yuantao Hou
- Department of Anesthesiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
| | - Hansheng Liang
- Department of Anesthesiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
| | - Cungang Fan
- Department of Neurosurgery, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China
| | - Ruen Liu
- Department of Neurosurgery, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China.
| | - Yi Feng
- Department of Anesthesiology, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, China.
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Holmlund P, Støverud KH, Wåhlin A, Wiklund U, Malm J, Jóhannesson G, Eklund A. Posture-Dependent Collapse of the Optic Nerve Subarachnoid Space: A Combined MRI and Modeling Study. Invest Ophthalmol Vis Sci 2021; 62:26. [PMID: 33877263 PMCID: PMC8083083 DOI: 10.1167/iovs.62.4.26] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We hypothesize that a collapse of the optic nerve subarachnoid space (ONSAS) in the upright posture may protect the eyes from large translamina cribrosa pressure differences (TLCPD) believed to play a role in various optic nerve diseases (e.g., glaucoma). In this study, we combined magnetic resonance imaging (MRI) and mathematical modeling to investigate this potential ONSAS collapse and its effects on the TLCPD. Methods First, we performed MRI on six healthy volunteers in 6° head-down tilt (HDT) and 13° head-up tilt (HUT) to assess changes in ONSAS volume (measured from the eye to the optic canal) with changes in posture. The volume change reflects optic nerve sheath (ONS) distensibility. Second, we used the MRI data and mathematical modeling to simulate ONSAS pressure and the potential ONSAS collapse in a 90° upright posture. Results The MRI showed a 33% decrease in ONSAS volume from the HDT to HUT (P < 0.001). In the upright posture, the simulations predicted an ONSAS collapse 25 mm behind lamina cribrosa, disrupting the pressure communication between the ONSAS and the intracranial subarachnoid space. The collapse reduced the simulated postural increase in TLCPD by roughly 1 mm Hg, although this reduction was highly sensitive to ONS distensibility, varying between 0 and 4.8 mm Hg when varying the distensibility by ± 1 SD. Conclusions The ONSAS volume along the optic nerve is posture dependent. The simulations supported the hypothesized ONSAS collapse in the upright posture and showed that even small changes in ONS stiffness/distensibility may affect the TLCPD.
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Affiliation(s)
- Petter Holmlund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | | | - Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Urban Wiklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| | - Gauti Jóhannesson
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden.,Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
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Guidoboni G, Sacco R, Szopos M, Sala L, Verticchio Vercellin AC, Siesky B, Harris A. Neurodegenerative Disorders of the Eye and of the Brain: A Perspective on Their Fluid-Dynamical Connections and the Potential of Mechanism-Driven Modeling. Front Neurosci 2020; 14:566428. [PMID: 33281543 PMCID: PMC7689058 DOI: 10.3389/fnins.2020.566428] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/19/2020] [Indexed: 01/22/2023] Open
Abstract
Neurodegenerative disorders (NDD) such as Alzheimer's and Parkinson's diseases are significant causes of morbidity and mortality worldwide. The pathophysiology of NDD is still debated, and there is an urgent need to understand the mechanisms behind the onset and progression of these heterogenous diseases. The eye represents a unique window to the brain that can be easily assessed via non-invasive ocular imaging. As such, ocular measurements have been recently considered as potential sources of biomarkers for the early detection and management of NDD. However, the current use of ocular biomarkers in the clinical management of NDD patients is particularly challenging. Specifically, many ocular biomarkers are influenced by local and systemic factors that exhibit significant variation among individuals. In addition, there is a lack of methodology available for interpreting the outcomes of ocular examinations in NDD. Recently, mathematical modeling has emerged as an important tool capable of shedding light on the pathophysiology of multifactorial diseases and enhancing analysis and interpretation of clinical results. In this article, we review and discuss the clinical evidence of the relationship between NDD in the brain and in the eye and explore the potential use of mathematical modeling to facilitate NDD diagnosis and management based upon ocular biomarkers.
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Affiliation(s)
- Giovanna Guidoboni
- Department of Electrical Engineering and Computer Science, Department of Mathematics, University of Missouri, Columbia, MO, United States
| | - Riccardo Sacco
- Department of Mathematics, Politecnico di Milano, Milan, Italy
| | | | | | - Alice Chandra Verticchio Vercellin
- IRCCS - Fondazione Bietti, Rome, Italy.,Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Ophthalmology, University of Pavia, Pavia, Italy
| | - Brent Siesky
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Alon Harris
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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The Influence of Translaminar Pressure Gradient and Intracranial Pressure in Glaucoma: A Review. J Glaucoma 2019; 29:141-146. [DOI: 10.1097/ijg.0000000000001421] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Fleischman D, Kaskar O, Shams R, Zhang X, Olson D, Zdanski C, Thorp BD, Kuznetsov AV, Grace L, Lee YZ. A Novel Porcine Model for the Study of Cerebrospinal Fluid Dynamics: Development and Preliminary Results. Front Neurol 2019; 10:1137. [PMID: 31708863 PMCID: PMC6819502 DOI: 10.3389/fneur.2019.01137] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/10/2019] [Indexed: 12/02/2022] Open
Abstract
Idiopathic intracranial hypertension, space-flight associated neuro-ocular syndrome (SANS), and glaucoma are conditions that are among a spectrum of cerebrospinal fluid (CSF)-related ophthalmologic disease. This implies that local CSF pressures at the level of the optic nerve are involved to variable extent in these disease processes. However, CSF pressure measurements are problematic due to invasiveness and interpretation. The pressure measured by a lumbar puncture is likely not the same as the orbital CSF pressure. It is believed this is at least in part due to the flow restrictive properties of the optic canal. To investigate CSF flow within the orbit, a model for CSF dynamics was created using three medium-sized pigs. Contrast was administered through a lumbar subarachnoid space access. The contrast front was imaged with repeated computed tomographic (CT) imaging. Once contrast entered the orbit, rapid, sequential CT imaging was performed until the contrast reached the posterior globe. Head tilting was performed to highlight the role of gravitational dependence within the subarachnoid space.
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Affiliation(s)
- David Fleischman
- Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Omkar Kaskar
- Department of Mechanical and Aerospace Engineering, NC State University, Raleigh, NC, United States
| | - Rayad Shams
- Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Xinxin Zhang
- Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Daniel Olson
- Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Carlton Zdanski
- Department of Otolaryngology, Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Brian D Thorp
- Department of Otolaryngology, Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Andrey V Kuznetsov
- Department of Mechanical and Aerospace Engineering, NC State University, Raleigh, NC, United States
| | - Landon Grace
- Department of Mechanical and Aerospace Engineering, NC State University, Raleigh, NC, United States
| | - Yueh Z Lee
- Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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