U T Eysel

Ruhr-Universität Bochum, Bochum, North Rhine-Westphalia, Germany

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Publications (9)5.95 Total impact

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    ABSTRACT: Optic nerve sheath fenestration (ONSF) is a surgical procedure that is sometimes performed in patients with optic disc edema from increased intracranial pressure. The objective of this study was to assess the consequence of ONSF on optic nerve axons, retinal ganglion cells (RGCs), and retinal amacrine cells. The optic nerves of 22 male Wistar rats were assigned to one of three groups. In Group 1 (n = 12), the rats underwent unilateral ONSF. In Group 2 (n = 10), the rat optic nerves were unilaterally exposed but were not operated on. Group 3 (n = 22) consisted of the optic nerves of Group 1 and Group 2 rats that were neither operated on nor exposed. Thirty days later, a cresyl violet staining method was used to assess the number and sizes of RGCs and amacrine cells. Optic nerve axons were assessed by means of glial fibrillary acidic protein (GFAP) immunoreactivity. ONSF was associated with a significant reduction (P < 0.05) in the number and size of RGCs and amacrine cells. Optic nerve axons were undisturbed. Although ONSF does not apparently injure the optic nerve axons, loss and shrinkage of RGCs is a caution when considering ONSF as a treatment.
    Journal of neuro-ophthalmology: the official journal of the North American Neuro-Ophthalmology Society 12/2009; 29(4):275-80. · 1.09 Impact Factor
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    ABSTRACT: Afferent disorders of the visual system are a potential consequence following orbital trauma. The aim of this study was to investigate the tolerance of neurons in the retinal ganglion cell layer to acute expanding retrobulbar lesions. In 42 male albino rats, intraorbital haemorrhage was simulated by transconjunctival insertion of a retrobulbar micro-balloon (filling volume 0.2-0.5 ml, duration of lesion 60 or 90 min). Neurodegeneration in the retinal ganglion cell layer was investigated by measuring the mean total neuron number and the mean neuron size. Increased retrobulbar volumes of 0.3 ml for 60 min led to a decrease in a number of neurons by 14.5% and in size of the neurons by 1.7%. Prolongation of the trauma to 90 min resulted in a decrease in number of neurons by 48.3% and in reduction of size of neurons by 22.1%. In contrast, a retrobulbar filling volume of 0.5 ml for 60 min resulted in a decrease in number of neurons by 11.4% and in size of neurons by 6.7%. The duration of a retrobulbar lesion leading to subsequent retinal ischaemia seems to be more important for neuron survival than the exerted pressure (once it is greater than a critical point for producing retinal ischaemia). The results strengthen the need for emergency treatment in cases of retrobulbar haemorrhage.
    Journal of Cranio-Maxillofacial Surgery 09/2002; 30(4):230-6. · 1.61 Impact Factor
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    ABSTRACT: Traumatic optic nerve lesions (TONL) are probable but unpredictable consequence after severe midface or skull base trauma. Based on a previously described rat model, the authors developed a new model in order to simulate optic nerve crush during trauma on the optic canal. To achieve a calibrated TONL, a microinjuring device was designed that made it possible to assess the correlation between a defined trauma and the neuronal degeneration in the rat retinal ganglion cell (RGC) layer. This device is based on a small dynamometer mounted onto a conventional micromanipulator. The supraorbital approach was chosen to expose the extracranial optic nerve. In this rat model (n=100, Wistar strain) the parameters of "force" and "time" could be precisely monitored during the experiment. The decrease in the mean number of retinal neurons (N) according to the pressure exerted (2-30 cN x mm(-2)) on the optic nerve was linear for 1, 6, and 15 minutes of injuring time; the decrease in N for varying injuring forces also appears to be nearly linear. The results show that this model provides a reliable method for studying quantitatively the anatomical effects of TONL on the RGC layer and the optic nerve itself, and may allow the design of treatment strategies following TONL.
    British Journal of Ophthalmology 03/2002; 86(2):233-7. · 2.73 Impact Factor
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    ABSTRACT: Traumatic optic nerve lesions (TONL) still pose a large clinical problem concerning early detection and treatment. Neuro-ophthalmology provides reliable tests to detect afferent lesions but these methods are limited to just 30% of the severely injured patients. Especially in the patient with multiple injuries, optic nerve injuries are hardly predictable. In the latter group we established well-known neurophysiological methods for early detection of afferent disorders of the visual pathway, i.e. flash-VEP ERG. Apart from these diagnostic problems of TONL, controversy still surrounds the appropriate treatment of TONL--whether conservative or surgical or even combined treatment should be advocated. Our aim was to establish a reliable diagnostic schedule, based on the combination of neuro-ophthalmological, spiral-CT and clinical findings, and a treatment plan, so that in any patient there is a distinct guideline as to whether there is a need for early treatment of the peripheral visual pathway or not. In 52 patients who were assessed by the above-mentioned schedule, we could detect any of the 20 afferent disorders of the peripheral visual pathway. Although it is difficult to prove therapeutic effects on the injured optic nerve, immediate combined conservative treatment plus optic nerve decompression helped in three patients, who reported unilaterally no light-perception at admission, to regain at least partial recovery of afferent function of the visual pathway. Most of the trauma units still handle the problem of optic nerve trauma with a 'wait and see' policy. This is not regarded as an up-to-date option, since there are alternatives, and these will be outlined.
    Mund- Kiefer- und Gesichtschirurgie 06/1998; 2 Suppl 1:S107-12.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Traumatic optic nerve lesions (TONL) still pose a large clinical problem concerning early detection and treatment. Neuro-ophthalmology provides reliable tests to detect afferent lesions but these methods are limited to just 30% of the severely injured patients. Especially in the patient with multiple injuries, optic nerve injuries are hardly predictable. In the latter group we established well-known neurophysiological methods for early detection of afferent disorders of the visual pathway, i.e. flash-VEP ERG. Apart from these diagnostic problems of TONL, controversy still surrounds the appropriate treatment of TONL - whether conservative or surgical or even combined treatment should be advocated. Our aim was to establish a reliable diagnostic schedule, based on the combination of neuro-ophthalmological, spiral-CT and clinical findings, and a treatment plan, so that in any patient there is a distinct guideline as to whether there is a need for early treatment of the peripheral visual pathway or not. In 52 patients who were assessed by the above-mentioned schedule, we could detect any of the 20 afferent disorders of the peripheral visual pathway. Although it is difficult to prove therapeutic effects on the injured optic nerve, immediate combined conservative treatment plus optic nerve decompression helped in three patients, who reported unilaterally no light-perception at admission, to regain at least partial recovery of afferent function of the visual pathway. Most of the trauma units still handle the problem of optic nerve trauma with a 'wait and see' policy. This is not regarded as an up-to-date option, since there are alternatives, and these will be outlined.
    Mund- Kiefer- und Gesichtschirurgie 05/1998; 2(Suppl 1):S107-12.
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    ABSTRACT: Traumatische Sehnervenschäden stellen eine klinische Herausforderung dar, da ihre Früherkennung und Behandlung nicht systematisiert sind. Neuroophthalmologische Tests sind prinzipiell sichere Verfahren zur Feststellung eines Sehbahnschadens, jedoch können sie lediglich in ca. 30% der schwer kopfverletzten Patienten erfolgreich angewendet werden; besonders bei polytraumatisierten Patienten sind Sehnervenschäden schwer zu erheben. Wir haben mit Hilfe der bekannten Blitz-VEP ERG-Untersuchung ein sicheres diagnostisches Element zur Früherkennung traumatischer Sehnervenschäden unabhängig vom Bewußtseinsgrad des Verletzten erarbeitet. Neben dem Problem der Früherkennung besteht Unsicherheit im Hinblick auf eine klare therapeutische Richtlinie für Patienten mit traumatischen Sehnervenschäden – konservative vs. chirurgische Therapie. Ziel dieser Arbeit war es, unabhängig von der Kooperationsfähigkeit des Patienten einen verläßlichen Plan zur interdisziplinären Früherkennung und Therapie traumatischer Sehnervenschäden auf der Basis von neuroophthalmologischen, Spiral-CT- und neurophysiologischen Befunden zu erstellen, so daß für jeden Patienten eine klare Richtlinie für oder gegen eine Therapie vorliegt. Insgesamt wurden 52 Patienten mit Hilfe dieses diagnostischen Stufenplans untersucht; hiervon konnten bei insgesamt 20 Patienten posttraumatische afferente Sehbahnschäden diagnostiziert werden. Obwohl der Beweis für einen Therapieerfolg nur schwer zu erbringen ist, konnte aus der Gruppe der kooperativen Patienten bei 3 einseitig amaurotischen Patienten nach unmittelbarer Einleitung der kombinierten konservativen und operativen Behandlung eine partielle Restitution der geschädigten Sehbahnfunktion erzielt werden. In den meisten Kliniken wird nach wie vor das Problem der traumatischen Sehnervenschädigung nach dem Wait-and-see-Prinzip angegangen. Wir halten ein solches Vorgehen für nicht gerechtfertigt, da es klare Alternativen gibt, die im folgenden vorgestellt werden sollen.
    Mund- Kiefer- und Gesichtschirurgie 01/1998; 2(7).
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    ABSTRACT: Traumatic optic nerve lesions (TONL) range from temporary affection of vision to avulsion of the optic nerve; often they are associated with more complex injuries. Usually Tonl are not regarded as an emergency. Up to now, we lack knowledge on the dependency of strength and duration of optic nerve lesions and the point of no return for afferent disorders of the visual pathway. We performed a prospective study on 50 patients with severe midface and skullbase fractures in order to find characteristic ophthalmological, computer tomographic und electrophysiological findings as indicators of TONL, independent of patient cooperation. We used an animal model (Wistar rats; n = 117) to study calibrated optic nerve lesions and the resulting neurodegeneration in the retinal ganglion cell (RGC) layer quantitatively. The electrophysiological investigation of the visual system (flash VEP/ERG) proved to be highly specific (0.97) and sensitive (1.0) for detecting TONL (n = 18). In the rat model, we could demonstrate a linear relationship between total neuron number reduction and strength and duration of calibrated optic nerve lesion. Experimental results indicate that optic nerve decompression is useful only within the first hours after TONL to reduce secondary optic nerve lesion. Indication for optic nerve decompression requires early detection of TONL, which is made possible by the combination of flash VEP/ERG.
    Der Ophthalmologe 12/1997; 94(11):807-14. · 0.53 Impact Factor
  • N C Gellrich, U T Eysel, E Machtens
    Fortschritte der Kiefer- und Gesichts-Chirurgie 02/1996; 41:1-6.
  • British Journal of Oral & Maxillofacial Surgery - BRIT J ORAL MAXILLOFAC SURG. 01/1996; 34(3):269-269.

Publication Stats

40 Citations
5.95 Total Impact Points

Institutions

  • 2002
    • Ruhr-Universität Bochum
      Bochum, North Rhine-Westphalia, Germany
    • Universitätsklinikum Freiburg
      • Oral and Maxillofacial Surgery Clinic
      Freiburg, Lower Saxony, Germany
  • 1998–2002
    • University of Freiburg
      Freiburg, Baden-Württemberg, Germany
  • 1997–1998
    • Deutsche Gesellschaft für Mund-, Kiefer- und Gesichtschirurgie e.V.
      Freiburg, Baden-Württemberg, Germany