Biomedical subjects

Robert Behr

Publications and source records attributed to Robert Behr.

4 recordsLinked to original sources

PubMed2004

Accuracy and stability of temperature probes for intracranial application.

Intracranial temperature measurement may play a pivotal role for prognosis and treatment of neurological and neurosurgical patients. For reliable clinical application, accurate temperature readings are therefore necessary. We present an independent in vitro study investigating the accuracy and stability of three temperature probes. Eight Neurovent-P Temp (RN), eight Licox temperature sensors (LT) and eight Neurotrend sensors (NT) were placed into a water bath. The temperature was increased in 3 degrees C increments from 30 to 42 degrees C before (accuracy test day 0) and after (accuracy test day 5) a long-term stability test run at 37 +/- 0.2 degrees C. The accuracy tests revealed deviations of <0.25, <0.2 and >0.4 degrees C for the RN, NT and LT probes, respectively, when compared to the reference measurement by a precision Pt100 temperature measuring instrument. All sensor types showed stable readings over the course of 120 h. The high variability of LT probes was due to a malfunctioning Licox monitor. Excluding these values reduced deviation below 0.21 degrees C the standard deviation at each temperature step was below +/-0.08 (RN, NT) and +/-0.12 (LT), laying within the range provided by the manufacturer (RN, NT: +/-0.1; LT: +/-0.2). In general, RN, NT and LT temperature measurement is reliable, but malfunctioning parts may lead to false interpretation of temperature readings. Therefore, validation of temperature probes to a reference temperature prior to clinical use is recommended.

Body Temperature↗

PubMed2003

Transluminal balloon angioplasty improves brain tissue oxygenation and metabolism in severe vasospasm after aneurysmal subarachnoid hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: The effect of transluminal balloon angioplasty on cerebral biochemical monitoring during treatment of severe cerebral vasospasm after subarachnoid hemorrhage (SAH) was investigated. CLINICAL PRESENTATION: In a 36-year-old man, an anterior communicating artery aneurysm caused an SAH (Hunt and Hess Grade IV, Fisher Grade III). After clipping, intraparenchymal monitoring (intracranial pressure, brain tissue oxygen tension [P(ti)O(2)], and microdialysis sampling of extracellular glucose, lactate, pyruvate, and glutamate) was initiated. Flow velocities obtained by transcranial Doppler sonography increased in the internal carotid artery (ICA)/middle cerebral artery bilaterally. INTERVENTION: After a decrease of P(ti)O(2) to less than 2 mm Hg and an increase of the lactate-to-pyruvate ratio to 44 in the territorial region of the left ICA, angiography demonstrated a 70 to 80% stenosis of the left ICA, which was dilated by a temporary occlusion balloon. This maneuver normalized the ICA diameter, P(ti)O(2) increased immediately from 1.5 to 40 mm Hg, the lactate-to-pyruvate ratio decreased from 44 to 30, and extracellular glucose increased from 0.4 to 0.9 mmol/L. No major changes in glutamate or intracranial pressure were seen. In the clinical follow-up, the patient showed a good recovery 6 months after SAH. CONCLUSION: Transluminal balloon angioplasty led to a continuous and effective resolution of cerebral vasospasm observed by sustained, improved cerebral biochemical parameters. Both P(ti)O(2) and lactate-to-pyruvate ratio might provide an early diagnosis of severe cerebral vasospasm after SAH and continuous surveillance of threatened tissue regions after transluminal balloon angioplasty.

Adult↗

PubMed2002

An auditory brainstem implant system.

Neurofibromastosis type II (NF2) is a condition that may result in bilateral acoustic neuromas. The tumors and their removal may cause profound bilateral deafness. Because the auditory nerve is compromised, people with NF2 are unable to receive a cochlear implant to restore a sensation of hearing. Electrical stimulation of the auditory pathway can provide hearing in such people. This is possible by means of an auditory brainstem implant (ABI). This article focuses on the MED-EL high-rate multichannel ABI system. The system consists of the implanted and external components. Appropriate placement of the ABI is dependent on electrical auditory brainstem response testing performed intra-operatively. Data on a group of European patients implanted with the MED-EL ABI are presented. Results are promising and include some open-set speech ability.

Acoustic Stimulation↗

PubMed2001

The fronto-orbital osteotomy as plastic-reconstructive approach to the anterior and middle skull base.

Introduction: A combined extra-intracranial access for the operative exploration of tumours of the anterior and middle skull base is indicated when the tumour extends intracranially and simultaneously into the nasal cavity, the paranasal sinuses or the orbit. Methods: Two standardized modifications of the fronto-orbital osteotomy, the fronto-orbito-nasal and the fronto-orbito-zygomatic osteotomy, allow safe removal of skull base tumours in these locations. In extensive skull base tumours, a modified bilateral fronto-orbital-zygomatic osteotomy can be used. Results: Between February 1993 and July 2000 skull base tumours in 111 patients were resected using the presented methods. The most frequent tumour type was meningioma in 29 cases. Complications were encountered in 13 cases (11.7%). Conclusion: The advantages over other approaches are good extra- and intracranial overview and minimal cerebral trauma. Additional transfacial incisions are not usually necessary. Exact repositioning of the fronto-orbital segments leads to optimal aesthetic results. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.

Journal Article↗