Biomedical subjects
Publications and source records attributed to F Heppner.
Intracranial malignant peripheral nerve sheath tumors (MPNST) and intrasellar schwannomas are rare tumors. We describe a case of an intrasellar schwannoma with progression to a MPNST, a finding that, although very rare, extends the differential diagnosis of intrasellar lesions.
Explore the source record for details and available documents.
This study identifies by microautoradiography activated microglia/macrophages as the main cell type expressing the peripheral benzodiazepine binding site (PBBS) at sites of active CNS pathology. Quantitative measurements of PBBS expression in vivo obtained by PET and [(11)C](R)-PK11195 are shown to correspond to animal experimental and human post-mortem data on the distribution pattern of activated microglia in inflammatory brain disease. Film autoradiography with [(3)H](R)-PK11195, a specific ligand for the PBBS, showed minimal binding in normal control CNS, whereas maximal binding to mononuclear cells was found in multiple sclerosis plaques. However, there was also significantly increased [(3)H](R)-PK11195 binding on activated microglia outside the histopathologically defined borders of multiple sclerosis plaques and in areas, such as the cerebral central grey matter, that are not normally reported as sites of pathology in multiple sclerosis. A similar pattern of [(3)H](R)-PK11195 binding in areas containing activated microglia was seen in the CNS of animals with experimental allergic encephalomyelitis (EAE). In areas without identifiable focal pathology, immunocytochemical staining combined with high-resolution emulsion autoradiography demonstrated that the cellular source of [(3)H](R)-PK11195 binding is activated microglia, which frequently retains a ramified morphology. Furthermore, in vitro radioligand binding studies confirmed that microglial activation leads to a rise in the number of PBBS and not a change in binding affinity. Quantitative [(11)C](R)-PK11195 PET in multiple sclerosis patients demonstrated increased PBBS expression in areas of focal pathology identified by T(1)- and T(2)-weighted MRI and, importantly, also in normal-appearing anatomical structures, including cerebral central grey matter. The additional binding frequently delineated neuronal projection areas, such as the lateral geniculate bodies in patients with a history of optic neuritis. In summary, [(11)C](R)-PK11195 PET provides a cellular marker of disease activity in vivo in the human brain.
Explore the source record for details and available documents.
Accompanied by Dante and Vergil the author compares persons and events of the "Divine Comedy" with those concerning the Austrian neurosurgery in the last 50 years. The burlesque description culminates in pointing out the wage rewarding the neurosurgeon at the end of the life for all troubles of his branch.
This paper describes an ultrasound-guided, laser-assisted, and TV-controlled endoscopic technique which has been used so far in 133 patients for a variety of intracranial lesions. Following CT or MRI image reconstruction, and a decision on the placement of a 1 cm or a 2 cm burrhole, a 1 cm 5.0 mHz or 7.5 mHz intraoperative ultrasound probe is used to direct the endoscope from the burrhole to the target area. A 22.5 cm long rigid endoscope tube with an outer diameter of 6 mm with an inbuilt suction irrigation system, Neodymium Yag laser with 600 micron Quartz glass-fibre and an inlet for various microinstruments is then introduced. The attachment of a TV camera to the ocular lens allows the operator to control further surgical steps in the target area via the TV screen and thus warrants sterility in the operating field. The technique has been used for evacuation of 77 spontaneous intracerebral haematomas (lobar, putaminal, thalamic), 8 traumatic intracerebral haematomas, 13 ventricular haematomas, 8 cerebellar haematomas and 1 brainstem haematoma. Total or subtotal evacuation was achieved in 33% of intracerebral haematomas, removal of more than 50% of the clot in 55%. Twenty-four brain tumours (12 ventricular, 12 cystic cerebral or cerebellar tumours) were operated on for biopsy, evacuation of cyst, resection or removal of the cyst wall and/or laser irradiation of solid tumour or the inner cyst wall of cystic tumours. The complication rate probably related to surgery was 1.6%, morbidity 1.6%, mortality 0%. This high-tec endoscopic technique with its minimal surgical trauma and short operation time can be recommended as a low-risk alternative to conventional neurosurgical techniques.
In glioblastoma multiforme and high-grade astrocytomas the following procedure has been implemented to try and prevent recurrence: after extirpation of the tumour its bed is lined with metal powder and the patient's head is exposed to a high-frequency magnetic field every 4 weeks. As a result the temperature is raised by induction to +45 degrees C at the boundary between metal and brain tissue. This ought to be sufficient to prevent tumour recurrence. Varied results were achieved using this technique in 103 patients.
Of a total of 580 patients suffering from expanding spinal disease, 15 cases of intramedullary lesions were dealt with by the use of the CO2 laser. Sharp cutting and precisely controlled depth effect are the advantages that make the CO2 laser very useful for surgery within the spinal cord. In tumors of tough consistency the neoplastic tissue is usually sharply demarcated, in which case the CO2 laser is used for dissection along this borderline, at an output energy of 15-20 W, infocus, continuous wave (CW). In tumors of soft consistency, characterized by a more-or-less diffuse zone of invasion--eg, glioblastomas-vaporization [20 W, out-of-focus, CW] and removal by ultrasound-microsuction is recommended. This procedure should advance layer by layer until normal looking tissue is reached. In this way intramedullary tumors may be removed with minimal side effects. The postoperative course involves less pain and less edematous reaction, and the rehabilitation time is shortened compared with conventional surgical treatment. In benign neoplasms long-term results are good; malignant cases require additional x-ray treatment and chemotherapy.
Explore the source record for details and available documents.
During a period of 34 years 1316 gliomas of the brain have been treated, among them 508 glioblastomas (= 39%). In addition to the operative removal and postoperative X-ray therapy of glioblastomas various attempts have been undertaken to prevent recurrences: Intracerebral application of Cobalt60 (6 patients); locally applied antimitotic agents (76 patients); bacterial liquefaction induced by intracarotid administration of Clostridium butyricum M 55 spores ("Oncolysis", 67 patients); circumscribed heating of the extirpation cavity with metal and high-frequency electromagnetic field (85 patients); vaporization of the tumour bed with the defocussed CO2- or Neodymium-YAG-Laser beam (177 patients). Permanent cure has been attained only in single cases so that the problem does not yet seem to be definitely solved by any of these methods. However, bacterial oncolysis in combination with the periodic postoperative generation of heat locally in the excision cavity of the tumour, might justify cautious optimism about future developments.
The introduction of lasers in neurosurgery in 1976 can be considered as a major contribution to gaining access to "untouchable" areas of the brain. This immaterial instrument provides for precise cutting at low penetration depth in surrounding tissues and may carbonize, and thus remove, layers not to be touched because of their highly sensitive vicinity. From a total of 794 patients experiencing the advantages of laser surgery (1976-1984), a series of 12 children with lower brainstem tumors is presented. Intraoperative instability of vital functions was absent throughout, leaving the patients without deterioration of their initial neurological condition. Given appropriate handling and adequate experience, the laser is a singularly helpful surgical tool for gaining access to areas hitherto barred to surgery.
A new endoscopic technique is presented, which allows burr hole evacuation of intracerebral hematomas under video control. Clot removal is achieved using a suction-irrigation system built in the 6-mm-diameter endoscope; in addition, an ultrasonic morcellement device has been developed for transendoscopic application. Small bleeding vessels in the hematoma cavity can be coagulated using a 1.5 mm Neodym YAG Laser microprobe introduced through the endoscope under visual control. A randomized prospective study has been started to raise again the question of indications for the surgical treatment of intracerebral hemorrhages, comparing medical treatment with the new surgical technique.
Explore the source record for details and available documents.
Flow property measurements were performed in a plexiglass model of six various types of end-to-side anastomosis (as clinically shown in extracranial to intracranial arterial bypass surgery). Three anastomoses were made without, another three anastomoses with a ringshaped stenosis restricting the lumen to between 25 and 46% of the cross-section as it occurs clinically by formation of thrombi out of the striching canals. A rectangular type and two of 45 degree oblique types--one directed centrally and one directed peripherally--were tested. Pressure head losses at the site of anastomosis were measured under various circumstances of different anastomoses and different flow speeds along the proximal portion of the middle cerebral artery and the superficial temporal artery. Flow resistance values originated by the different types of anastomoses were expressed in terms of additional recipient vessel length. Differences between different types of anastomoses with and without stenosis were very small and under no circumstances exceeded the equivalent of lengthening the recipient vessel by 2 cm. Theoretically, the optimal type of anastomosis is the oblique and centrally directed version; the worst type is the rectangular form. Practically, however, such differences are not relevant. The explanation for such unexpectedly small differences can rheologically be given by considering the dominating role of blood viscosity under the given circumstances, other variables such as short stenosis and angling of flow playing a secondary role.
New technical tools in surgery are only beneficial if they offer real improvements compared to the traditional techniques or if they open absolute new indications in surgery. Therefore we have tried to find absolute indications for the use of the indifferent laser system. Due to the specific wavelength the CO2-Laser is entirely absorbed at the surface. This specific performance allows one to use the CO2-Laser as the most precise cutting and as a completely new vaporizing instrument. It has become an irreplaceable tool in surgery of central lesions and brain stem tumours and also for spinal cord tumours. In addition the CO2-Laser is adaptable to the operating microscope. A gain of the same importance in the meantime is the Nd-YAG Laser, which works specially for coagulation, volume coagulation and endoscopic use. It is certain that laser surgery will evolve for beyond our imagination.
Explore the source record for details and available documents.
Explore the source record for details and available documents.