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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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Kheram N, Boraschi A, Pfender N, Spiegelberg A, Kurtcuoglu V, Curt A, Schubert M, Zipser CM. Queckenstedt's test repurposed for the quantitative assessment of the cerebrospinal fluid pulsatility curve. Acta Neurochir (Wien) 2023; 165:1533-1543. [PMID: 37079108 DOI: 10.1007/s00701-023-05583-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 03/16/2023] [Indexed: 04/21/2023]
Abstract
PURPOSE Before the era of spinal imaging, presence of a spinal canal block was tested through gross changes in cerebrospinal fluid pressure (CSFP) provoked by manual compression of the jugular veins (referred to as Queckenstedt's test; QT). Beyond these provoked gross changes, cardiac-driven CSFP peak-to-valley amplitudes (CSFPp) can be recorded during CSFP registration. This is the first study to assess whether the QT can be repurposed to derive descriptors of the CSF pulsatility curve, focusing on feasibility and repeatability. METHOD Lumbar puncture was performed in lateral recumbent position in fourteen elderly patients (59.7±9.3 years, 6F) (NCT02170155) without stenosis of the spinal canal. CSFP was recorded during resting state and QT. A surrogate for the relative pulse pressure coefficient was computed from repeated QTs (i.e., RPPC-Q). RESULTS Resting state mean CSFP was 12.3 mmHg (IQR 3.2) and CSFPp was 1.0 mmHg (0.5). Mean CSFP rise during QT was 12.5 mmHg (7.3). CSFPp showed an average 3-fold increase at peak QT compared to the resting state. Median RPPC-Q was 0.18 (0.04). There was no systematic error in the computed metrics between the first and second QT. CONCLUSION This technical note describes a method to reliably derive, beyond gross CSFP increments, metrics related to cardiac-driven amplitudes during QT (i.e., RPPC-Q). A study comparing these metrics as obtained by established procedures (i.e., infusion testing) and by QT is warranted.
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Affiliation(s)
- Najmeh Kheram
- Department of Neurology and Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Andrea Boraschi
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Nikolai Pfender
- Department of Neurology and Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
| | - Andreas Spiegelberg
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Vartan Kurtcuoglu
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Armin Curt
- Department of Neurology and Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Schubert
- Department of Neurology and Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
| | - Carl Moritz Zipser
- Department of Neurology and Neurophysiology, Balgrist University Hospital, Zurich, Switzerland.
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Kheram N, Boraschi A, Pfender N, Friedl S, Rasenack M, Fritz B, Kurtcuoglu V, Schubert M, Curt A, Zipser CM. Cerebrospinal Fluid Pressure Dynamics as a Bedside Test in Traumatic Spinal Cord Injury to Assess Surgical Spinal Cord Decompression: Safety, Feasibility, and Proof-of-Concept. Neurorehabil Neural Repair 2023; 37:171-182. [PMID: 36919616 PMCID: PMC10152574 DOI: 10.1177/15459683231159662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
BACKGROUND Sufficient and timely spinal cord decompression is a critical surgical objective for neurological recovery in spinal cord injury (SCI). Residual cord compression may be associated with disturbed cerebrospinal fluid pressure (CSFP) dynamics. OBJECTIVES This study aims to assess whether intrathecal CSFP dynamics in SCI following surgical decompression are feasible and safe, and to explore the diagnostic utility. METHODS Prospective cohort study. Bedside lumbar CSFP dynamics and cervical MRI were obtained following surgical decompression in N = 9 with mostly cervical acute-subacute SCI and N = 2 patients with non-traumatic SCI. CSFP measurements included mean CSFP, cardiac-driven CSFP peak-to-valley amplitudes (CSFPp), Valsalva maneuver, and Queckenstedt's test (firm pressure on jugular veins, QT). From QT, proxies for cerebrospinal fluid pulsatility curve were calculated (ie, relative pulse pressure coefficient; RPPC-Q). CSFP metrics were compared to spine-healthy patients. computer tomography (CT)-myelography was done in 3/8 simultaneous to CSFP measurements. RESULTS Mean age was 45 ± 9 years (range 17-67; 3F), SCI was complete (AIS A, N = 5) or incomplete (AIS B-D, N = 6). No adverse events related to CSFP assessments. CSFP rise during QT was induced in all patients [range 9.6-26.6 mmHg]. However, CSFPp was reduced in 3/11 (0.1-0.3 mmHg), and in 3/11 RPPC-Q was abnormal (0.01-0.05). Valsalva response was reduced in 8/11 (2.6-23.4 mmHg). CSFP dynamics corresponded to CT-myelography. CONCLUSIONS Comprehensive bedside lumbar CSFP dynamics in SCI following decompression are safe, feasible, and can reveal distinct patterns of residual spinal cord compression. Longitudinal studies are required to define critical thresholds of impaired CSFP dynamics that may impact neurological recovery and requiring surgical revisions.
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Affiliation(s)
- Najmeh Kheram
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland.,Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Andrea Boraschi
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Nikolai Pfender
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Susanne Friedl
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Maria Rasenack
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Benjamin Fritz
- Department of Radiology, Balgrist University Hospital, Zurich, Switzerland
| | | | - Martin Schubert
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Carl M Zipser
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
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Karimi F, Neufeld E, Fallahi A, Boraschi A, Zwanenburg JJM, Spiegelberg A, Kurtcuoglu V, Kuster N. Theory for a non-invasive diagnostic biomarker for craniospinal diseases. Neuroimage Clin 2023; 37:103280. [PMID: 36508887 PMCID: PMC9763738 DOI: 10.1016/j.nicl.2022.103280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022]
Abstract
Monitoring intracranial pressure (ICP) and craniospinal compliance (CC) is frequently required in the treatment of patients suffering from craniospinal diseases. However, current approaches are invasive and cannot provide continuous monitoring of CC. Dynamic exchange of blood and cerebrospinal fluid (CSF) between cranial and spinal compartments due to cardiac action transiently modulates the geometry and dielectric properties of the brain. The resulting impedance changes can be measured and might be usable as a non-invasive CC surrogate. A numerically robust and computationally efficient approach based on the reciprocity theorem was developed to compute dynamic impedance changes resulting from small geometry and material property changes. The approach was successfully verified against semi-analytical benchmarks, before being combined with experimental brain pulsation data to study the information content of the impedance variation. The results indicate that the measurable signal is dominated by the pulsatile displacement of the cortical brain surface, with minor contributions from the ventricular surfaces and from changes in brain perfusion. Different electrode setups result in complementary information. The information content from the investigated three electrode pairs was employed to successfully infer subject-specific brain pulsation and motion features. This suggests that non-invasive CC surrogates based on impedance monitoring could be established.
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Affiliation(s)
- Fariba Karimi
- Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland; Department of Information Technology and Electrical Engineering, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland.
| | - Esra Neufeld
- Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland
| | - Arya Fallahi
- Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland; Department of Information Technology and Electrical Engineering, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Andrea Boraschi
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Jaco J M Zwanenburg
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Andreas Spiegelberg
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Vartan Kurtcuoglu
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Niels Kuster
- Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland; Department of Information Technology and Electrical Engineering, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
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Lalou AD, Czosnyka M, Placek MM, Smielewski P, Nabbanja E, Czosnyka Z. CSF Dynamics for Shunt Prognostication and Revision in Normal Pressure Hydrocephalus. J Clin Med 2021; 10:jcm10081711. [PMID: 33921142 PMCID: PMC8071572 DOI: 10.3390/jcm10081711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Despite the quantitative information derived from testing of the CSF circulation, there is still no consensus on what the best approach could be in defining criteria for shunting and predicting response to CSF diversion in normal pressure hydrocephalus (NPH). OBJECTIVE We aimed to review the lessons learned from assessment of CSF dynamics in our center and summarize our findings to date. We have focused on reporting the objective perspective of CSF dynamics testing, without further inferences to individual patient management. DISCUSSION No single parameter from the CSF infusion study has so far been able to serve as an unquestionable outcome predictor. Resistance to CSF outflow (Rout) is an important biological marker of CSF circulation. It should not, however, be used as a single predictor for improvement after shunting. Testing of CSF dynamics provides information on hydrodynamic properties of the cerebrospinal compartment: the system which is being modified by a shunt. Our experience of nearly 30 years of studying CSF dynamics in patients requiring shunting and/or shunt revision, combined with all the recent progress made in producing evidence on the clinical utility of CSF dynamics, has led to reconsidering the relationship between CSF circulation testing and clinical improvement. CONCLUSIONS Despite many open questions and limitations, testing of CSF dynamics provides unique perspectives for the clinician. We have found value in understanding shunt function and potentially shunt response through shunt testing in vivo. In the absence of infusion tests, further methods that provide a clear description of the pre and post-shunting CSF circulation, and potentially cerebral blood flow, should be developed and adapted to the bed-space.
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Affiliation(s)
- Afroditi Despina Lalou
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
- Correspondence: ; Tel.: +44-774-3567-585
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
- Institute of Electronic Systems, Faculty of Electronics and Information Sciences, Warsaw University of Technology, 00-661 Warsaw, Poland
| | - Michal M. Placek
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
| | - Peter Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
| | - Eva Nabbanja
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
| | - Zofia Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK; (M.C.); (M.M.P.); (P.S.); (E.N.); (Z.C.)
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Isaacs AM, Williams MA, Hamilton MG. Current Update on Treatment Strategies for Idiopathic Normal Pressure Hydrocephalus. Curr Treat Options Neurol 2019; 21:65. [PMID: 31792620 DOI: 10.1007/s11940-019-0604-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Idiopathic normal pressure hydrocephalus (iNPH) is a surgically treatable neurological disorder of the elderly population that is characterized by abnormal ventricular enlargement due to cerebrospinal fluid (CSF) accumulation and gait disturbance, cognitive impairment, or urinary incontinence. The objective of this review is to present the current diagnostic and treatment approaches for iNPH and to discuss some of the postoperative modalities that complement positive surgical outcomes. RECENT FINDINGS Although historically reported patient outcomes following iNPH surgery were dismal and highly variable, recent advances in terms of better understanding of the iNPH disease process, better standardization of iNPH diagnostic and treatment processes arising from the adoption of clinical guidelines for diagnosis, treatment and in research methodologies, and availability of long-term follow-up data, have helped reduce the variations to a much improved 73 to 96% reported good outcomes. With careful evaluation, good patient selection, and advanced surgical techniques, iNPH can be surgically treated to return patients close to their pre-iNPH functional status. Institution of an interdisciplinary effort to rehabilitate patients following surgery may help augment their recovery.
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Affiliation(s)
- Albert M Isaacs
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA.,Division of Neurosurgery, Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Michael A Williams
- Adult and Transitional Hydrocephalus and CSF Disorders, Departments of Neurology and Neurological Surgery, University of Washington School of Medicine, Seattle, WA, USA
| | - Mark G Hamilton
- Division of Neurosurgery, Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada. .,Adult Hydrocephalus Program, Department of Clinical Neuroscience, University of Calgary, Foothills Medical Centre - 12th Floor, Neurosurgery, 1403 - 29 Street NW, Calgary, Alberta, T2N 2T9, Canada.
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Virhammar J, Laurell K, Cesarini KG, Larsson EM. Increase in callosal angle and decrease in ventricular volume after shunt surgery in patients with idiopathic normal pressure hydrocephalus. J Neurosurg 2018; 130:130-135. [DOI: 10.3171/2017.8.jns17547] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 08/01/2017] [Indexed: 11/06/2022]
Abstract
OBJECTIVEPostoperative decrease in ventricle size is usually not detectable either by visual assessment or by measuring the Evans index in patients with idiopathic normal pressure hydrocephalus (iNPH). The aim of the present study was to investigate whether the angle between the lateral ventricles (the callosal angle [CA]) increases and ventricular volume decreases after shunt surgery in patients with iNPH.METHODSMagnetic resonance imaging of the brain was performed before and 3 months after shunt surgery in 18 patients with iNPH. The CA and Evans index were measured on T1-weighted 3D MR images, and ventricular volume contralateral to the shunt valve was measured with quantitative MRI.RESULTSThe CA was larger postoperatively (mean 78°, 95% CI 69°–87°) than preoperatively (mean 67°, 95% CI 60°–73°; p < 0.001). The volume of the lateral ventricle contralateral to the shunt valve decreased from 73 ml (95% CI 66–80 ml) preoperatively to 63 ml (95% CI 54–72 ml) postoperatively (p < 0.001). The Evans index was 0.365 (95% CI 0.35–0.38) preoperatively and 0.358 (95% CI 0.34–0.38) postoperatively (p < 0.05). Postoperative change of CA showed a negative correlation with change of ventricular volume (r = −0.76, p < 0.01).CONCLUSIONSIn this sample of patients with iNPH, the CA increased and ventricular volume decreased after shunt surgery. The relative difference was most pronounced for the CA, indicating that this accessible, noninvasive radiological marker should be evaluated further as an indirect method to determine shunt function in patients with iNPH.
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Affiliation(s)
| | - Katarina Laurell
- 2Department of Pharmacology and Clinical Neuroscience, Unit of Neurology, Umeå University, Umeå, Sweden
| | | | - Elna-Marie Larsson
- 4Department of Surgical Sciences, Radiology, Uppsala University, Uppsala; and
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Lindén C, Qvarlander S, Jóhannesson G, Johansson E, Östlund F, Malm J, Eklund A. Normal-Tension Glaucoma Has Normal Intracranial Pressure: A Prospective Study of Intracranial Pressure and Intraocular Pressure in Different Body Positions. Ophthalmology 2017; 125:361-368. [PMID: 29096996 DOI: 10.1016/j.ophtha.2017.09.022] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/14/2017] [Accepted: 09/19/2017] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To test the hypothesis that normal-tension glaucoma (NTG) is caused by an increased pressure difference across the lamina cribrosa (LC) related to a low intracranial pressure (ICP). DESIGN Prospective case-control study. PARTICIPANTS Thirteen NTG patients (9 women; median 71 [range: 56-83] years) were recruited for investigation with the same protocol as 11 healthy volunteers (8 women; 47 [30-59] years). A larger control group (n = 51; 30 women; 68 [30-81] years) was used only for ICP comparison in supine position. METHODS ICP and intraocular pressure (IOP) were simultaneously measured in supine, sitting, and 9° head-down tilt (HDT) positions. Trans-lamina cribrosa pressure difference (TLCPD) was calculated using ICP and IOP together with geometric distances estimated from magnetic resonance imaging to adjust for hydrostatic effects. MAIN OUTCOME MEASURES ICP, IOP, and TLCPD in different body positions. RESULTS Between NTG patients and healthy volunteers, there were no differences in ICP, IOP, or TLCPD in supine, sitting, or HDT (P ≥ 0.11), except for IOP in HDT (P = 0.04). There was no correlation between visual field defect and TLCPD, IOP, or ICP and in any body position (P ≥ 0.39). Mean ICP in supine was 10.3 mmHg (SD = 2.7) in the NTG group (n = 13) and 11.3 (2.2) mmHg in the larger control group (n = 51) (P = 0.24). CONCLUSIONS There was no evidence of reduced ICP in NTG patients as compared with healthy controls, either in supine or in upright position. Consequently, the hypothesis that NTG is caused by an elevated TLCPD from low ICP was not supported.
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Affiliation(s)
- Christina Lindén
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden.
| | - Sara Qvarlander
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Gauti Jóhannesson
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| | - Elias Johansson
- Department of Pharmacology and Clinical Neuroscience, Neurology, Umeå University, Umeå, Sweden
| | - Fanny Östlund
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Pharmacology and Clinical Neuroscience, Neurology, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
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Abstract
PURPOSE OF REVIEW This article provides neurologists with a pragmatic approach to the diagnosis and treatment of idiopathic normal pressure hydrocephalus (iNPH), including an overview of: (1) key symptoms and examination and radiologic findings; (2) use of appropriate tests to determine the patient's likelihood of shunt responsiveness; (3) appropriate referral to tertiary centers with expertise in complex iNPH; and (4) the contribution of neurologists to the care of patients with iNPH following shunt surgery. RECENT FINDINGS The prevalence of iNPH is higher than previously estimated; however, only a fraction of persons with the disorder receive shunt surgery. iNPH should be considered as a diagnosis for patients with unexplained symmetric gait disturbance, a frontal-subcortical pattern of cognitive impairment, and urinary urge incontinence, whose MRI scans show enlarged ventricles and whose comorbidities are not sufficient to explain their symptoms. Physiologically based tests, such as the tap test (large-volume lumbar puncture) or temporary spinal catheter insertion for external lumbar drainage with gait testing before and after CSF removal, or CSF infusion testing for measurement of CSF outflow resistance, can reliably identify patients who are likely to respond to shunt surgery. Properly selected patients have an 80% to 90% chance of responding to shunt surgery, and all symptoms can improve following shunt surgery. Longitudinal care involves investigating the differential diagnosis of any symptoms that either fail to respond to shunt surgery or that worsen after initial improvement from shunt surgery. SUMMARY Neurologists play an important role in the identification of patients who should be evaluated for possible iNPH. With contemporary diagnostic tests and treatment with programmable shunts, the benefit-to-risk ratio of shunt surgery is highly favorable. For more complex patients, tertiary centers with expertise in complex iNPH are available throughout the world.
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Can intracranial pressure be measured non-invasively bedside using a two-depth Doppler-technique? J Clin Monit Comput 2016; 31:459-467. [DOI: 10.1007/s10877-016-9862-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 03/08/2016] [Indexed: 10/22/2022]
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CSF dynamic analysis of a predictive pulsatility-based infusion test for normal pressure hydrocephalus. Med Biol Eng Comput 2013; 52:75-85. [DOI: 10.1007/s11517-013-1110-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 09/01/2013] [Indexed: 10/26/2022]
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Andersson K, Manchester IR, Laurell K, Cesarini KG, Malm J, Eklund A. Measurement of CSF dynamics with oscillating pressure infusion. Acta Neurol Scand 2013; 128:17-23. [PMID: 23278837 DOI: 10.1111/ane.12063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2012] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Infusion tests are used to diagnose and select patients with idiopathic normal pressure hydrocephalus (INPH) for shunt surgery. The test characterizes cerebrospinal fluid dynamics and estimates parameters of the cerebrospinal fluid system, the pressure-volume index (PVI) and the outflow conductance (Cout). The Oscillating Pressure Infusion (OPI) method was developed to improve the test and reduce the investigation time. The aim of this study was to evaluate the new OPI method by comparing it with an established reference method. METHODS Forty-seven patients (age 71.2 ± 8.9 years) with communicating hydrocephalus underwent a preoperative lumbar infusion investigation with two consecutive infusion protocols, reference (42 min) and new (20 min), that is, 94 infusion tests in total. The OPI method estimated Cout and PVI simultaneously. A real-time analysis of reliability was applied to investigate the possibility of infusion time reduction. RESULTS The difference in Cout between the methods was 1.2 ± 1.8 μl/s/kPa (ΔRout = -0.8 ± 3.5 mmHg/ml/min), P < 0.05, n = 47. With the reliability analysis, the preset 20 min of active infusion could have been even further reduced for 19 patients to between 10 and 19 min. PVI was estimated to 16.1 ± 6.9 ml, n = 47. CONCLUSIONS The novel Oscillating Pressure Infusion method produced real-time estimates of Cout including estimates of reliability that was in good agreement with the reference method and allows for a reduced and individualized investigation time.
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Affiliation(s)
- K. Andersson
- Department of Radiation Sciences; Biomedical Engineering, Umeå University; Umeå; Sweden
| | - I. R. Manchester
- Computer Science and Artificial Intelligence Laboratory; Massachusetts Institute of Technology; Cambridge; MA; USA
| | | | | | - J. Malm
- Department of Clinical Neuroscience; Umeå University; Umeå; Sweden
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Eklund A, Koskinen LOD, Williams MA, Luciano MG, Dombrowski SM, Malm J. Hydrodynamics of the Certas™ programmable valve for the treatment of hydrocephalus. Fluids Barriers CNS 2012; 9:12. [PMID: 22643114 PMCID: PMC3386893 DOI: 10.1186/2045-8118-9-12] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 05/29/2012] [Indexed: 11/30/2022] Open
Abstract
Background The new Certas™ shunt for the treatment of hydrocephalus has seven standard pressure settings that according to the manufacturer range from 36 to 238 mmH2O, and an additional “Virtual Off” setting with an opening pressure >400 mmH2O. Information on actual pressure response and reliability of shunt performance is important in clinical application, especially the “Virtual Off” setting as a non-surgical replacement for shunt ligation. The objective of this study was to evaluate the in-vitro hydrodynamic performance of the Certas™ shunt. Methods Six new Certas™ shunts with proximal and distal catheters were tested with an automated, computerized test system that raised the pressure from zero to a maximum pressure and back to zero at each valve setting. Opening pressure and flow resistance were determined. Results For settings 1–7 the measured opening pressure range was 26 to 247 mmH2O, and the mean change in opening pressure for a one-step adjustment was between 33 and 38 mmH2O. For setting 8 (“Virtual Off”) the measured mean opening pressure was 494 ± 34 mmH2O (range 451 to 556 mmH2O). The mean outflow resistance was 7.0 mmHg/ml/min (outflow conductance 17.9 μl/s/kPa). Conclusions The six shunts had similar characteristics and closely matched the manufacturer’s specifications for opening pressure at settings 1–7. The opening pressure for the “Virtual Off” setting was nearly 500 mmH2O, which is 100 mmH2O higher than the manufacturer’s specification of “>400” and should be functionally off for most patients with communicating hydrocephalus. Clinical studies are needed to evaluate if the CSF dynamic profile persists after implantation in patients.
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Affiliation(s)
- Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, S-901 85, Sweden.
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