Telemetrische Messung des intrakraniellen Drucks in der pädiatrischen Neurochirurgie

Introduction: Telemetric intracranial pressure measurement (tICPM) enables the measurement of intracranial pressure (ICP) in different conditions, such as body posture and activity. Neurovent-P-Tel (P-Tel, Raumedic, Helmbrechts, Germany) and sensor reservoir (SR, Miethke, Potsdam, Germany) are among the most used systems, and their employment influences the management of patients with cerebrospinal fluid (CSF) circulation disturbances. The SR has added several advantages in the follow-up of patients. The aim of this work is to assess the in vitro and in vivo performance of tICPM devices and to describe new achievements in maneuver measurements in pediatric neurosurgery. Materials and methods: Six SRs were tested and compared to standard invasive ICP measurement methods in an experimental setting. In vivo data from 21 patients in a mixed P-Tel and SR population (8 with a P-Tel and 13 with an SR) was retrospectively evaluated. Additionally, a specific measurement protocol, combining different body positions, ventilation patterns and jugular compression, was developed and applied in 17 SR-implanted patients. Results: In vitro testing showed a significant similarity between SRs and invasive pressure measuring systems. The in vivo dataset contained measurements from a total of 21 patients (median age 16.5 years, range 10–39.5 years). A maneuver protocol was applied in one population with a ventriculoperitoneal shunt system, and in another with a stand-alone SR for diagnostic purposes only. There were 13 shunted patients (median age 15.8 years, range 4.0–35.2 years), and 6 were non-shunted (median age 11.9 years, range 3.6–17.7 years). A total of 480 measurements were performed. tICPM-guided shunt adjustments led to clinical improvements in 7 P-Tel (75%) and 6 SR (76.9%) patients, with shunt survival rates of 44.4% at 77.9 months and 83.3% at 42 months, respectively. Three secondary shunt implantations were indicated in the stand-alone population. Comparative analysis in intracranial pressure and amplitude among stand-alone and shunted SR patients showed differences in the changes of these two parameters: in the shunted group, intracranial pressure showed more significant variations, while the non-shunted population showed a more drastic change in amplitude. Conclusions: SRs were confirmed to have a good reliability in vitro. tICPM is well-established and helpful in clinical practice – especially in complex shunt-dependent patients with chronic symptomatology. The introduction of an analysis tool improved the throughput of the data analysis, but data processing remains cumbersome. Future improvements will focus on the elaboration of relevant parameters and performing tests.Fragestellung: Die telemetrische intrakranielle Druckmessung (tICPM) ermöglicht die Messung des intrakraniellen Drucks (ICP) unter verschiedenen Bedingungen (Körperhaltung, Aktivität). Neurovent-P-Tel (P-Tel, Raumedic, Helmbrechts, Deutschland) und Sensor-Reservoir (SR, Miethke, Potsdam, Deutschland) gehören zu den am häufigsten verwendeten Systemen, und ihr Einsatz hat Einfluss auf das Management von Patienten mit Liquorzirkulationsstörungen. Das SR hat mehrere Vorteile in der Patientenbehandlung gebracht. Ziel dieser Arbeit ist es, die In-vitro- und In-vivo-Leistung von tICPM-Geräten zu bewerten und neue Perspektiven bei Manövermessungen in der pädiatrischen Neurochirurgie zu beschreiben. Materialien und Methoden: Sechs SR wurden experimentell getestet und mit invasiven Standardmethoden zur ICP-Messung verglichen. In-vivo-Daten von 21 Patienten aus einer gemischten P-Tel- und SR-Population (8 P-Tel und 13 SR) wurden retrospektiv ausgewertet. Darüber hinaus wurde ein spezifisches Messprotokoll entwickelt, das verschiedene Körperpositionen, Beatmungsmuster und Jugularkompression kombiniert und bei 17 SR-implantierten Patienten angewendet wurde. Ergebnisse: In-vitro-Tests zeigten eine signifikante Ähnlichkeit zwischen SRs und invasiven Druckmesssystemen. Der In-vivo-Datensatz enthielt Messungen von 21 Patienten (mittleres Alter 16.5 Jahre, Range 10-39.5 Jahre). Ein Manöverprotokoll wurde bei einer Population mit einem Shuntsystem und bei einer mit „stand-alone“ SR zu rein diagnostischen Zwecken angewendet. An 13 Shunt-Patienten (medianes Alter 15.8 Jahre, Range 4.0-35.2 Jahre) und 6 Nicht-Shunt-Patienten (medianes Alter 11.9 Jahre, Range 3.6-17.7 Jahre) wurden 480 Messungen durchgeführt. Die tICPM-gesteuerten Shuntanpassungen führten bei 7 P-Tel- (75 %) und 6 SR-Patienten (76.9 %) zu klinischen Verbesserungen, mit Shunt-Überlebensraten von 44.4 % nach 77.9 Monaten bzw. 83.3 % nach 42 Monaten. Drei sekundäre Shunt-Implantationen waren in der Stand-alone-Population indiziert. Eine Vergleichsanalyse des intrakraniellen Drucks und der Amplitude zwischen „stand-alone“- und Shunt-SR-Patienten zeigte Unterschiede in den Veränderungen dieser beiden Parameter: In der Shunt-Gruppe wies der intrakranielle Druck deutlichere Veränderungen auf, während die nicht geshuntete Population eine drastischere Veränderung der Amplitude zeigte. Schlussfolgerungen: Es wurde bestätigt, dass die SRs in vitro eine gute Zuverlässigkeit aufweisen. tICPM ist in der klinischen Praxis gut etabliert und hilfreich - insbesondere bei komplexen shuntabhängigen Patienten mit chronischer Symptomatik. Die Einführung eines Analysetools verbesserte den Durchsatz der Datenanalyse, aber die Datenverarbeitung ist umständlich. Künftige Verbesserungen werden sich auf die Ausarbeitung der relevanten Parameter und die Durchführung von Tests konzentrieren

An Implantable Low Pressure, Low Drift, Dual BioPressure Sensor and In-Vivo Calibration Methods Thereof

The human body’s intracranial pressure (ICP) is a critical component in sustaining healthy blood flow to the brain while allowing adequate volume for brain tissue within the rigid structures of the cranium. Disruptions in the body’s autoregulation of intracranial pressure are often caused by hemorrhage, tumors, edema, or excess cerebral spinal fluid resulting in treatments that are estimated to globally cost up to approximately five billion dollars annually. A critical element in the contemporary management of acute head injury, intracranial hemorrhage, stroke, or other conditions resulting in intracranial hypertension, is the real-time monitoring of ICP. Currently, such mainstream clinical monitoring can only take place short-term within an acute care hospital. The monitoring is prone to measurement drift and is comprised of externally tethered pressure sensors that are temporarily implanted into the brain, thus carrying a significant risk of infection. To date, reliable, low drift, completely internalized, long-term ICP monitoring devices remain elusive. The successful development of such a device would not only be safer and more reliable in the short-term but would expand the use of ICP monitoring for the management of chronic intracranial hypertension and enable further clinical research into these disorders. The research herein reviews the current challenges of existing ICP monitoring systems, develops a new novel sensing technology, and evaluates the same for potentially facilitating long-term implantable ICP sensing. Based upon the findings of this research, this dissertation proposes and evaluates a dual matched-die piezo-resistive strain sensing device, with a novel in-vivo calibration system and method thereof, for application to long-term implantable ICP sensing

Applications of aerospace technology in biology and medicine

Utilization of National Aeronautics and Space Administration (NASA) technology in medicine is discussed. The objective is best obtained by stimulation of the introduction of new or improved commercially available medical products incorporating aerospace technology. A bipolar donor/recipient model of medical technology transfer is presented to provide a basis for the team's methodology. That methodology is designed to: (1) identify medical problems and NASA technology that, in combination, constitute opportunities for successful medical products; (2) obtain the early participation of industry in the transfer process; and (3) obtain acceptance by the medical community of new medical products based on NASA technology. Two commercial transfers were completed: the Stowaway, a lightweight wheelchair that provides mobility for the disabled and elderly in the cabin of commercial aircraft, and Micromed, a portable medication infusion pump for the reliable, continuous infusion of medications such as heparin or insulin. The marketing and manufacturing factors critical to the commercialization of the lightweight walker incorporating composite materials were studied. Progress was made in the development and commercialization of each of the 18 currently active projects

Outdated Ventriculoperitoneal Shunts and their Effects on Quality of Life: An Interdisciplinary Study

Though many people in the medical field are aware of patients having a low quality of life from ventriculoperitoneal shunts not having updated material and technology, many choose to look at the problem through only one disciplinary perspective. In light of this issue, the sole purpose of this study was to use an interdisciplinary perspective on how outdated ventriculoperitoneal shunts affect quality of life as well as express technology advancement recommendations through this type of analysis. This study involved extensive interdisciplinary work on the causes and symptoms of intracranial pressure, types and advancements of shunt valves, and surgery outcomes and lasting effects. The research in these areas of study identified why ventriculoperitoneal shunts are out of date, as well as the affects on quality of life in a patient from multidisciplinary perspectives. The literature review included previously established biopsychology, physiology, and technology discipline analysis to better understand the issue. This study reviewed these three disciplines and used an interdisciplinary approach to expand and organize their individual perspectives to properly analyze how outdated ventriculoperitoneal shunts affect quality of life. Through interdisciplinary analysis, the information developed in the research of multiple disciplines produced the proposal of adding biopsychology to improve overall treatment plans, and enhance the manufacture of technological advancements for ventriculoperitoneal shunts and, most importantly, create a better quality of life for patient with hydrocephalus.https://openprairie.sdstate.edu/honors_isp/1012/thumbnail.jp

Intracranial Pressure Monitoring in Cerebrospinal Fluid Dynamics Disturbances

There are numerous gaps in the knowledge of Intracranial Pressure (ICP) physiology and Cerebrospinal Fluid (CSF) dynamics. This PhD answers some of the research questions posed by these gaps, through the use of invasive ICP monitoring in patients with suspected CSF dynamics disturbances. Research on CSF dynamics disturbances has mainly focused on conditions that cause high ICP, whilst only sparse attention has been centred on low CSF pressure/volume states. Chapter 3 and chapter 4 of this thesis are focused on Spontaneous Intracranial Hypotension (SIH). Chapter 3 is a comprehensive systematic review and meta-analysis of the clinical presentation, investigation findings and treatment outcomes of this disease. Chapter 4 is an observational study that investigated the utility of invasive ICP monitoring when there is diagnostic uncertainty for SIH. This study demonstrates that, in selected cases, ICP monitoring can be useful and confirm a low-pressure state in 8% of the patients and identify a paradoxical clinical presentation with an underlying high-pressure state in 16% of the patients. Chapters 5 and 6 provide evidence on the way that ICP and brain compliance respond to external variables, such as changes in posture and shunt setting adjustments. Chapter 5 is a retrospective observational study that describes the changes of ICP and pulse amplitude with different postures. Chapter 6 is a retrospective observational study investigating the effect of valve setting adjustments on ICP. This study demonstrates that paradoxical changes in ICP following differential pressure valves setting changes can occur. Chapters 7 and 8 investigate the possibility of replacing invasive ICP monitoring with non-invasive biomarkers of raised ICP. Chapter 7 demonstrated the association between higher ICP measurements and the absence of spontaneous retinal venous pulsations detected with infrared video recordings. Chapter 8 demonstrates the utility of integrating ophthalmic and imaging biomarkers to predict raised ICP

Diagnostic and Therapeutic MEMS (Micro-Electro-Mechanical Systems) Devices for the Identification and Treatment of Human Disease

abstract: Early detection and treatment of disease is paramount for improving human health and wellness. Micro-scale devices promote new opportunities for the rapid, cost-effective, and accurate identification of altered biological states indicative of disease early-onset; these devices function at a scale more sensitive to numerous biological processes. The application of Micro-Electro-Mechanical Systems (MEMS) in biomedical settings has recently emerged and flourished over course of the last two decades, requiring a deep understanding of material biocompatibility, biosensing sensitively/selectively, biological constraints for artificial tissue/organ replacement, and the regulations in place to ensure device safety. Capitalizing on the inherent physical differences between cancerous and healthy cells, our ultra-thin silicone membrane enables earlier identification of bladder cancer—with a 70% recurrence rate. Building on this breakthrough, we have devised an array to multiplex this sample-analysis in real-time as well as expanding beyond bladder cancer. The introduction of new materials—with novel properties—to augment current and create innovative medical implants requires the careful analysis of material impact on cellular toxicity, mutagenicity, reactivity, and stability. Finally, the achievement of replacing defective biological systems with implanted artificial equivalents that must function within the same biological constraints, have consistent reliability, and ultimately show the promise of improving human health as demonstrated by our hydrogel check valve. The ongoing proliferation, expanding prevalence, and persistent improvement in MEMS devices through greater sensitivity, specificity, and integration with biological processes will undoubtedly bolster medical science with novel MEMS-based diagnostics and therapeutics.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

The best marker for guiding the clinical management of patients with raised intracranial pressure: the RAP index or the mean pulse amplitude?

Raised intracranial pressure is a common problem in a variety of neurosurgical conditions including traumatic brain injury, hydrocephalus and intracranial haemorrhage. The clinical management of these patients is guided by a variety of haemodynamic, biochemical and clinical factors. However to date there is no single parameter that is used to guide clinical management of patients with raised intracranial pressure (ICP). However, the role of ICP indices, specifically the mean pulse amplitude (AMP) and RAP index [correlation coefficient (R) between AMP amplitude (A) and mean ICP pressure (P); index of compensatory reserve], as an indicator of true ICP has been investigated. Whilst the RAP index has been used both as a descriptor of neurological deterioration in TBI patients and as a way of characterising the compensatory reserve in hydrocephalus, more recent studies have highlighted the limitation of the RAP index due to the influence that baseline effect errors have on the mean ICP, which is used in the calculation of the RAP index. These studies have suggested that the ICP mean pulse amplitude may be a more accurate marker of true intracranial pressure due to the fact that it is uninfluenced by the mean ICP and, therefore, the AMP may be a more reliable marker than the RAP index for guiding the clinical management of patients with raised ICP. Although further investigation needs to be undertaken in order to fully assess the role of ICP indices in guiding the clinical management of patients with raised ICP, the studies undertaken to date provide an insight into the potential role of ICP indices to treat raised ICP proactively rather than reactively and therefore help prevent or minimise secondary brain injury