{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T05:45:46Z","timestamp":1782452746220,"version":"3.54.5"},"reference-count":45,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2026,6,18]],"date-time":"2026-06-18T00:00:00Z","timestamp":1781740800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Introduction: Decompressive craniectomy (DC) is often required to stabilize the intracranial pressure (ICP) in patients with traumatic brain injury (TBI). Both sinking flap syndrome (SFS) and hydrocephalus are known complications of DC. The pathophysiology of each is unknown. Case Report: We report on a patient who underwent DC for TBI who suffered both SFS and low-pressure hydrocephalus. We measured the changes in volumes of each hemisphere and the ventricles with CT and the cerebral blood flow (CBF) and aqueduct flow with phase-contrast MRI during different stages of the disease process. Discussion: The SFS in this patient was associated with a reduction in volume of both supratentorial cavities. There was a significant reduction in CBF bilaterally, which increased by an average of 26% following cranioplasty. During the low-pressure hydrocephalus phase of the patient\u2019s illness, there was reversed CSF flow directed toward the ventricles. Once the ventricles returned to normal size, this reversed flow was lost. Conclusions: Lumped parameter modelling of the patients\u2019 CSF and vascular systems suggested a new hypothesis, i.e., that the reduction in blood flow was due to reversible constriction of the arterioles secondary to a reset of the autoregulation rather than compression of the venous structures. We suggest there is an increase in CSF absorption efficiency despite the known CSF-absorption mechanisms being unlikely to function at such a low ICP. A hypothesis is put forward that CSF absorption occurs via the brain capillary bed in these diseases.<\/jats:p>","DOI":"10.3390\/jcm15124753","type":"journal-article","created":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T13:04:04Z","timestamp":1781874244000},"page":"4753","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The Pathophysiology of Sinking Flap Syndrome Associated with Low-Pressure Hydrocephalus: A Case Study Suggests a New Hypothesis"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3095-9047","authenticated-orcid":false,"given":"Grant A.","family":"Bateman","sequence":"first","affiliation":[{"name":"Department of Medical Imaging, John Hunter Hospital, Newcastle, NSW 2310, Australia"},{"name":"School of Medicine and Public Health, College of Health, Medicine and Wellbeing, University of Newcastle, Callaghan, NSW 2308, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6090-5344","authenticated-orcid":false,"given":"Alexander R.","family":"Bateman","sequence":"additional","affiliation":[{"name":"Discipline of Aerospace, Mechanical and Mechatronics Engineering, School of Engineering, College of Engineering, Science and Environment, University of Newcastle, Callaghan, NSW 2308, Australia"},{"name":"Brain Health Research Program, Hunter Medical Research Institute, Newcastle, NSW 2310, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1493","DOI":"10.1056\/NEJMoa1102077","article-title":"Decompressive craniectomy in diffuse traumatic brain injury","volume":"364","author":"Cooper","year":"2011","journal-title":"N. Engl. J. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"100589","DOI":"10.1016\/j.wnsx.2026.100589","article-title":"Analysis of persistent sunken brain after cranioplasty as a cause of extracerebral fluid collection","volume":"30","author":"Nomura","year":"2026","journal-title":"World Neurosurg. X"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"43","DOI":"10.2176\/nmc.17pt1.43","article-title":"Neurological deficits in the presence of the sinking skin flap following decompressive craniectomy","volume":"17","author":"Yamaura","year":"1977","journal-title":"Neurol. Med. Chir."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1486","DOI":"10.1097\/PRS.0000000000006836","article-title":"Syndrome of the Trephined: Quantitative Functional Improvement after Large Cranial Vault Reconstruction","volume":"145","author":"Tarr","year":"2020","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"124789","DOI":"10.1016\/j.wneu.2026.124789","article-title":"Management of Low\/Negative Pressure Hydrocephalus: A Systematic Review of Etiology, Pathophysiology, and Treatment","volume":"207","author":"Bakmeedeniya","year":"2026","journal-title":"World Neurosurg."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1056\/NEJM196507152730301","article-title":"Symptomatic Occult Hydrocephalus with \u201cNormal\u201d Cerebrospinal-Fluid Pressure. A Treatable Syndrome","volume":"273","author":"Adams","year":"1965","journal-title":"N. Engl. J. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"643","DOI":"10.1227\/00006123-199410000-00010","article-title":"Low-pressure hydrocephalic state and viscoelastic alterations in the brain","volume":"35","author":"Pang","year":"1994","journal-title":"Neurosurgery"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1007\/s12028-015-0144-7","article-title":"Complications Associated with Decompressive Craniectomy: A Systematic Review","volume":"23","author":"Kurland","year":"2015","journal-title":"Neurocrit. Care"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"128","DOI":"10.13004\/kjnt.2023.19.e24","article-title":"Recent Updates on Controversies in Decompressive Craniectomy and Cranioplasty: Physiological Effect, Indication, Complication, and Management","volume":"19","author":"Kim","year":"2023","journal-title":"Korean J. Neurotrauma"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Bouma, G.J., Muizelaar, J.P., Schuurman, R., Fatouros, P., and Marmarou, A. (1993). Cerebral Blood Volume in Acute Head Injury: Relationship to CBF and ICP, Springer.","DOI":"10.1007\/978-3-642-77789-9_115"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1186\/s12987-024-00532-w","article-title":"Regulation of brain fluid volumes and pressures: Basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus","volume":"21","author":"Hladky","year":"2024","journal-title":"Fluids Barriers CNS"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1007\/s10143-004-0326-9","article-title":"Radiological assessment of hydrocephalus: New theories and implications for therapy","volume":"27","author":"Greitz","year":"2004","journal-title":"Neurosurg. Rev."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"204","DOI":"10.1093\/neuros\/nyx054","article-title":"Effects of Cranioplasty on Cerebral Blood Flow Following Decompressive Craniectomy: A Systematic Review of the Literature","volume":"81","author":"Halani","year":"2017","journal-title":"Neurosurgery"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1548","DOI":"10.3171\/2019.7.JNS191077","article-title":"Intracranial pressure before and after cranioplasty: Insights into intracranial physiology","volume":"133","author":"Andresen","year":"2020","journal-title":"J. Neurosurg."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"e2837","DOI":"10.1097\/MD.0000000000002837","article-title":"Paradoxical Herniation After Unilateral Decompressive Craniectomy Predicts Better Patient Survival: A Retrospective Analysis of 429 Cases","volume":"95","author":"Chen","year":"2016","journal-title":"Medicine"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1007\/BF01406039","article-title":"Effect of cranioplasty on cerebrospinal fluid hydrodynamics in patients with the syndrome of the trephined","volume":"70","author":"Fodstad","year":"1984","journal-title":"Acta Neurochir."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"44","DOI":"10.3325\/cmj.2026.67.44","article-title":"Craniospinal cerebrospinal fluid volume changes after extreme bilateral frontotemporoparietal craniectomy and cranioplasty: A volumetric magnetic resonance imaging case report","volume":"67","author":"Marasanov","year":"2026","journal-title":"Croat. Med. J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3555","DOI":"10.1007\/s00234-025-03830-8","article-title":"Data-Driven differentiation of idiopathic Normal-Pressure hydrocephalus and progressive supranuclear palsy via automated volumetric analysis","volume":"67","author":"Yun","year":"2025","journal-title":"Neuroradiology"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"e510","DOI":"10.1016\/j.wneu.2018.12.123","article-title":"Diagnosis and Management for Secondary Low- or Negative-Pressure Hydrocephalus and a New Hydrocephalus Classification Based on Ventricular Pressure","volume":"124","author":"Wu","year":"2019","journal-title":"World Neurosurg."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"e002657","DOI":"10.1161\/JAHA.115.002657","article-title":"Age-Related Changes of Normal Cerebral and Cardiac Blood Flow in Children and Adults Aged 7 Months to 61 Years","volume":"5","author":"Wu","year":"2016","journal-title":"J. Am. Heart Assoc."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"667","DOI":"10.1148\/radiology.209.3.9844657","article-title":"Effect of age on cerebral blood flow: Measurement with ungated two-dimensional phase-contrast MR angiography in 250 adults","volume":"209","author":"Buijs","year":"1998","journal-title":"Radiology"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1586","DOI":"10.1089\/neu.2015.4261","article-title":"The Effect of Cranioplasty on Cerebral Hemodynamics as Measured by Perfusion Computed Tomography and Doppler Ultrasonography","volume":"33","author":"Paredes","year":"2016","journal-title":"J. Neurotrauma"},{"key":"ref_23","first-page":"695","article-title":"Comprehensive cognitive and cerebral hemodynamic evaluation after cranioplasty","volume":"10","author":"Coelho","year":"2014","journal-title":"Neuropsychiatr. Dis. Treat."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"269","DOI":"10.3390\/brainsci15030269","article-title":"Brain Ischemia in Alzheimer\u2019s Disease May Partly Counteract the Disruption of the Blood\u2013Brain Barrier","volume":"15","author":"Bateman","year":"2025","journal-title":"Brain Sci."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Bateman, G.A., and Bateman, A.R. (2025). A Lumped Parameter Modelling Study of Idiopathic Intracranial Hypertension Suggests the CSF Formation Rate Varies with the Capillary Transmural Pressure. Brain Sci., 15.","DOI":"10.3390\/brainsci15050527"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"24373","DOI":"10.1038\/s41598-024-75214-6","article-title":"A lumped parameter modelling study of cerebral autoregulation in normal pressure hydrocephalus suggests the brain chooses to be ischemic","volume":"14","author":"Bateman","year":"2024","journal-title":"Sci. Rep."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Bateman, G.A., and Bateman, A.R. (2024). A Lumped Parameter Model Suggests That Infusion Studies Overestimate the Cerebrospinal Fluid Outflow Resistance in Normal Pressure Hydrocephalus. Brain Sci., 14.","DOI":"10.20944\/preprints202411.1975.v1"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Bateman, G.A., and Bateman, A.R. (2025). A Lumped Parameter Modelling Study of Leukoaraiosis Suggests Its Vascular Pathophysiology May Be Similar to Normal-Pressure Hydrocephalus. Brain Sci., 15.","DOI":"10.20944\/preprints202508.0063.v1"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1186\/s12987-017-0066-1","article-title":"Comparison of the sagittal sinus cross-sectional area between patients with multiple sclerosis, hydrocephalus, intracranial hypertension and spontaneous intracranial hypotension: A surrogate marker of venous transmural pressure?","volume":"14","author":"Bateman","year":"2017","journal-title":"Fluids Barriers CNS"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"tkad033","DOI":"10.1093\/burnst\/tkad033","article-title":"Cellular and molecular mechanisms in vascular repair after traumatic brain injury: A narrative review","volume":"11","author":"Zhao","year":"2023","journal-title":"Burns Trauma"},{"key":"ref_31","first-page":"623","article-title":"Cerebral venous pressure, sinus pressure and intracranial pressure","volume":"20","author":"Benabid","year":"1974","journal-title":"Neurochirurgie"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"R909","DOI":"10.1152\/ajpregu.2001.281.3.R909","article-title":"Spinal and cranial contributions to total cerebrospinal fluid transport","volume":"281","author":"Mollanji","year":"2001","journal-title":"Am. J. Physiol. Regul. Integr. Comp. Physiol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"e5159","DOI":"10.1002\/nbm.5159","article-title":"Human brain clearance imaging: Pathways taken by magnetic resonance imaging contrast agents after administration in cerebrospinal fluid and blood","volume":"37","author":"Wahlin","year":"2024","journal-title":"NMR Biomed."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2433","DOI":"10.1152\/jappl.1987.63.6.2433","article-title":"Central venous pressure in humans during short periods of weightlessness","volume":"63","author":"Norsk","year":"1987","journal-title":"J. Appl. Physiol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"851","DOI":"10.1016\/j.neuroscience.2004.07.033","article-title":"Water homeostasis in the brain: Basic concepts","volume":"129","author":"Kimelberg","year":"2004","journal-title":"Neuroscience"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"106159","DOI":"10.1016\/j.nbd.2023.106159","article-title":"Mechanisms of cerebrospinal fluid and brain interstitial fluid production","volume":"183","author":"Xiang","year":"2023","journal-title":"Neurobiol. Dis."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Lee, M.J., Kim, Y.E., Chang, H.J., An, J.H., Pyo, C.H., Jeong, J., Kim, T., Chang, J., Oh, E., and Chung, W. (J. Adv. Res., 2026). Brain Barriers in Normal Pressure Hydrocephalus: Mechanisms and Therapeutic Perspectives, J. Adv. Res., in press.","DOI":"10.1016\/j.jare.2026.04.026"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"e70106","DOI":"10.1111\/jon.70106","article-title":"Cerebral Perfusion and Blood-Brain Barrier Changes After Cranioplasty: A Diffusion-Prepared Arterial Spin Labeling Study","volume":"35","author":"Ojogho","year":"2025","journal-title":"J. Neuroimaging"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Wilhelmy, F., Krause, M., Schob, S., Merkenschlager, A., Wachowiak, R., Hartig, W., Meixensberger, J., Gburek-Augustat, J., and Wende, T. (2023). Cerebrospinal Fluid Protein Concentrations in Hydrocephalus. Children, 10.","DOI":"10.3390\/children10040644"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/j.exger.2018.01.027","article-title":"Changes of cerebrospinal fluid protein concentrations and gait patterns in geriatric normal pressure hydrocephalus patients after ventriculoperitoneal shunting surgery","volume":"106","author":"Chen","year":"2018","journal-title":"Exp. Gerontol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/j.mayocp.2022.10.012","article-title":"Population-Based Evaluation of Total Protein in Cerebrospinal Fluid","volume":"98","author":"Fautsch","year":"2023","journal-title":"Mayo Clin. Proc."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1111\/j.1528-1167.2012.03472.x","article-title":"Are you in or out? Leukocyte, ion, and neurotransmitter permeability across the epileptic blood-brain barrier","volume":"53","author":"Janigro","year":"2012","journal-title":"Epilepsia"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1161\/01.RES.49.3.557","article-title":"Capillary fluid filtration. Starling forces and lymph flow","volume":"49","author":"Taylor","year":"1981","journal-title":"Circ. Res."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1002\/jmri.1880030213","article-title":"Accuracy of phase-contrast flow measurements in the presence of partial-volume effects","volume":"3","author":"Tang","year":"1993","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1850","DOI":"10.3171\/2015.6.JNS15496","article-title":"Phase-contrast magnetic resonance imaging reveals net retrograde aqueductal flow in idiopathic normal pressure hydrocephalus","volume":"124","author":"Ringstad","year":"2016","journal-title":"J. Neurosurg."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/12\/4753\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T04:48:23Z","timestamp":1782449303000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/12\/4753"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,18]]},"references-count":45,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["jcm15124753"],"URL":"https:\/\/doi.org\/10.3390\/jcm15124753","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,18]]}}}