Cochlear Implants and Auditory Brainstem Implants
R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne in Scott-Brown's Essential Otorhinolaryngology, 2022
Complications of CI surgery include standard complications of mastoid surgery (see Chapter 10). In addition, patients must be warned of the risk of device failure and of meningitis. For the latter reason, patients should have the 23-valent polysaccharide pneumococcal vaccination (given after the age of 2) in addition to the childhood meningitis immunisation programme. Intraoperative cerebrospinal fluid (CSF) leak can occur when making the cochleostomy or RW opening in patients with inner ear malformations but can be managed by raising the head of the bed and inserting the electrode with a soft tissue seal around it; lumbar drainage is rarely required. Occasionally the electrode cannot be inserted fully due to cochlear fibrosis/ossification, e.g. due to meningitis or otosclerosis. In some cases, it is necessary to drill out the basal turn of the cochlea or even insert a split electrode for which an additional channel is drilled into the middle turn of the cochlea. Tip folds over of the electrode in the cochlea and facial nerve stimulation from the CI are complications that can usually be managed by altering the stimulation settings for the CI. Some patients also experience chronic pain following surgery, which rarely necessitates device explantation. There is a risk of magnet displacement with MRI and the make of implant should always be checked and appropriate precautions taken prior to such imaging.
Disorders of Circulation of the Cerebrospinal Fluid
Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw in Hankey's Clinical Neurology, 2020
Cerebrospinal fluid (CSF) has an estimated total volume of approximately 150 mL, and the CSF volume is larger in men than women. CSF column is also increased in older individuals than younger individuals due to an increase in ventricular size that compensates for tissue loss with age within an unchanging bony cranium. Approximately two-thirds or 100 mL of the CSF is located intracranially within the ventricles and extra-axial spaces. One-third of the CSF volume or 50 mL is located in the spinal compartment. These compartments communicate with one another in a predictable pattern. In the recumbent position, CSF pressure is equalized between the ventricles and the brain and spinal subarachnoid spaces. In the erect position, a pressure gradient forms with lower pressures at the vertex (sometimes negative) and higher pressures in the lumbar subarachnoid space.
Spine surgery wound and drain management
Michael Y. Wang, Andrea L. Strayer, Odette A. Harris, Cathy M. Rosenberg, Praveen V. Mummaneni in Handbook of Neurosurgery, Neurology, and Spinal Medicine for Nurses and Advanced Practice Health Professionals, 2017
Intraoperatively, most dural tears are identified and repaired. The onset of cerebrospinal fluid (CSF) leak symptoms may be delayed. In addition to postural headache, CSF leak symptoms include photophobia, nausea, and vomiting. Rule out etiologies such as orthostatic hypotension, dehydration, migraine, and caffeine withdrawal.Evaluate labs, medications, and drain output trends.Consider testing drain fluid for beta-2 transferrin to differentiate CSF leak.Consider MRI evaluation of CSF leak.Use initial conservative treatment including hydration, caffeine, and bed rest. A lumbar subarachnoid drain may be inserted to divert CSF (Khazim et al., 2015).
Decline of stress resilience in aging rats: Focus on choroid plexus-cerebrospinal fluid-hippocampus
Published in The World Journal of Biological Psychiatry, 2023
Kaige Liu, Huizhen Li, Ningxi Zeng, Wenjun Lu, Xiaofeng Wu, Hanfang Xu, Can Yan, Lili Wu
Choroid plexus (CP), a highly vascularised tissue, is the major site of cerebrospinal fluid (CSF) production. Stress and ageing can both result in morphologic changes in CP, including volume reduction, cellular atrophy, microvilli shortening, thickening of the basement membrane, and so on (Kaur et al. 2016; Kratzer et al. 2020). Low expression of receptors and transporters on CP may induce transport dysregulation, and thus affect CSF constituents (Wu et al. 2020). During normal ageing, CSF exhibits reduced production and increased circulation resistance, with downregulated neurotrophins (Lugert et al. 2017). Physiologically, hippocampus is adjacent to the lateral ventricles. CSF composition can act directly on hippocampus, proceeding to changes in hippocampal structure and function, such as regulating neurogenesis, neuronal survival, and synaptic plasticity (Ziegler et al. 2015).
Posterior reversible encephalopathy syndrome during convalescence from COVID-19
Published in International Journal of Neuroscience, 2023
Anaclara Michel-Chávez, Miguel García-Grimshaw, Oswaldo Alan Chávez-Martínez, Carlos Cantú-Brito, Griselda Teresa Romero-Sánchez, Fernando Daniel Flores-Silva, Francisco Javier Merayo-Chalico, Francisco Manuel Martínez-Carrillo, Ana Barrera-Vargas, Sergio Iván Valdés-Ferrer
A head CT revealed bilateral hypodense lesions on the parietal and occipital lobes posterior regions suggestive of PRES. We started her on levetiracetam with a complete resolution of seizures. An electroencephalogram performed one hour after the second episode revealed generalized slow background rhythm within theta range without epileptiform activity. Cerebrospinal fluid (CSF) analysis was normal; protein content: 40 mg/dL (normal range: 15–45); white blood cell count: 0 cells/μL (normal range: 0–10); glucose: 72 mg/dL (normal range: 40–70); and CSF/serum glucose ratio of 0.64. Gram stain, cultures, testing for herpes simplex viruses 1 and 2, Epstein-Barr virus, varicella-zoster virus, and SARS-CoV-2 by RT-PCR were negative. Other inflammatory biomarkers in the CSF were not investigated.
Dural venous sinus stenting in patients with idiopathic intracranial hypertension: report of outcomes from a single-center prospective database and literature review
Published in Expert Review of Ophthalmology, 2022
Matthew J Kole, Juan Carlos Martinez-Gutierrez, Francisio Sanchez, Rosa Tang, Peng Roc Chen
Cerebrospinal fluid (CSF) is produced in the choroid plexus within the ventricles of the brain at a steady rate. After circulating the subarachnoid space, it is then cleared by reabsorption through arachnoid granulations into the venous sinuses [8]. Although the precise mechanistic underpinnings of IIH are not known, an overabundance of CSF is believed to be a cause of increased intracranial pressure. It is unclear if IIH arises from an enhanced production or poor clearance of CSF but its removal results in resolution of IIH [9]. Given the role of the cerebral venous sinuses in CSF clearance, it is possible that their disruption can contribute to IIH. Cerebral venous sinus stenosis (VSS) is observed in 93% of patients with IIH [10]. However, debate about the order in which VSS and IIH appear remains. Illustrative cases have demonstrated that after CSF diversion, VSS can resolve, pointing to VSS being a secondary event from intracranial pressure external compression [11]. Others have demonstrated persistence of VSS despite CSF diversion pointing toward VSS being the primary etiology [12]. The final common pathway of either of the proposed mechanisms could result in a feed-forward loop of elevated intracranial pressure causing venous sinus compression, which in turn causes a further increase in intracranial pressure. As we discuss in the following sections, mounting evidence exists for enhancing CSF clearance by VSS stenting normalizing intracranial pressure.