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Biomedical subjects

H R Eggert

Publications and source records attributed to H R Eggert.

At least 19 recordsLinked to original sources
PubMed1992

Central nervous system lesions in von Hippel-Lindau syndrome.

CNS manifestations were studied in 97 gene carriers of von Hippel-Lindau syndrome (HLS). Haemangioblastomas of the CNS were found in 43 patients (44%), 23 females and 20 males. The mean age at diagnosis was 39 years (12-73 years). A total of 93 haemangioblastomas were detected of which 74% were intracranial and 26% were located in the spinal cord; 75% were predominantly cystic and 25% presented as solid lesions. Multiple lesions were found in 42% of HLS-associated haemangioblastomas, but in none of 51 patients with CNS haemangioblastoma without HLS. Haemangioblastoma was the cause of death in 82% of patients with HLS. Although microsurgery has considerably improved post-operative results, multifocal tumour development and recurrence remain a serious problem in the clinical management of HLS gene carriers.

Adolescent↗
PubMed1991

Microsurgery of deep-seated cavernous angiomas: report of 26 cases.

The authors review 26 patients with deep-seated cavernous angiomas which were removed by microsurgery. Ten of the angiomas were located in the insula and basal ganglia, 2 in the thalamus, 5 in the midbrain, 8 in the pons, and 1 in the brachium pontis. The patients were among 73 consecutive cases operated on between August 1983 and December 1989 for symptomatic cavernous angiomas in various locations. In 11 cases total excision of the cavernoma was achieved without producing additional neurological deficits. Postoperative neurological recovery was delayed in 7 patients. In the remaining 8, the complicated postoperative course was caused by bleeding from residual parts of the malformation or damage to long-tract pathways in two cases, respectively, vascular injury during dissection in three cases, and paradoxical air embolism in one case. In order to achieve a satisfactory surgical result, it is stressed that particular attention has to be paid to the operative approach, to careful dissection and complete removal of the malformation, to perforating arteries, and to anomalous venous drainage.

Adolescent↗
PubMed1990

Mesenchymal chondrosarcoma of the craniocervical junction.

Mesenchymal chondrosarcomas are found with equal low frequency in bone and soft tissue. The CNS is the most commonly reported site of extraosseous origin of mesenchymal chondrosarcomas. This report concerns the CT, MRI, and pathologic findings as well as the operative management of a mesenchymal chondrosarcoma of the craniocervical junction.

Adult↗
PubMed1990

Cerebrovascular and metabolic effects on the rat brain of focal Nd:YAG laser irradiation.

To investigate the effects of focal neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation (lambda = 1060 nm) on regional cerebral blood flow, cerebral protein synthesis, and blood-brain barrier permeability, the parietal brain surface of 44 rats was irradiated with a focused laser beam at a constant output energy of 30 J. Survival times ranged from 5 minutes to 48 hours. Laser irradiation immediately caused well-defined cortical coagulation necrosis. Within 5 minutes after unilateral irradiation, 14C-iodoantipyrine autoradiographs demonstrated severely reduced blood flow to the irradiation site and perilesional neocortex, but a distinct reactive hyperemia in all other areas of the forebrain. Apart from a persistent ischemic focus in the vicinity of the cortical coagulation necrosis, blood flow alterations in remote areas of the brain subsided within 3 hours after irradiation. Autoradiographic assessment of 3H-tyrosine incorporation into brain proteins revealed rapid onset and prolonged duration of protein synthesis inhibition in perifocal morphologically intact cortical and subcortical structures. Impairment of amino acid incorporation proved to be completely reversible within 48 hours. Immunoautoradiographic visualization of extravasated plasma proteins using 3H-labeled rabbit anti-rat immunoglobulins-showed that, up to 1 hour after irradiation, immunoreactive proteins were confined to the neocortex at the irradiation site. At 4 hours, vasogenic edema was present in the vicinity of the irradiation site and the subcortical white matter, and, at later stages (16 to 36 hours), also extended into the contralateral hemisphere. Although this was followed by a gradual decrease in labeling intensity, resolution of edema was still not complete after 48 hours. Analysis of sequential functional changes in conjunction with morphological alterations indicates that the evolution of morphological damage after laser irradiation does not correlate with the time course and spatial distribution of protein synthesis inhibition or vasogenic edema. Although the central coagulation necrosis represents a direct effect of radiation, the final size of the laser-induced lesion is determined by a delayed colliquation necrosis due to persistent perifocal ischemia. Extent and severity of ischemia in a zone with initial preservation of neuroglial cells can be explained by the optical properties of the Nd:YAG laser; extensive scattering of light within brain parenchyma associated with a high blood-to-brain absorption ratio selectively affects blood vessels outside the irradiation focus.

Amino Acids↗
PubMed1989

Microsurgical unilateral approaches for spinal tumour surgery: eight years' experience in 256 primary operated patients.

A series of 256 consecutive patients suffering from spinal tumours was studied with respect to the value of bilateral or unilateral surgical approaches. The case material included 152 extradural, 87 intradural, extramedullary and 17 intramedullary tumours. The cervical spinal cord was involved in 43, the thoracic in 152 and the lumbosacral region in 61 cases. Hemilaminectomy was chosen mainly for juxtamedullary tumours, while laminectomy was used for intramedullary tumours. No remarkable difference regarding the choice of approaches was found in extradural tumours. More than 60% of cervical or lumbosacral tumours were managed using unilateral procedures. A higher rate of surgical radicality but fewer complications, shorter stay in hospital and better early results were achieved using hemilaminectomy especially in patients with juxtamedullary tumours. From the observations it may be concluded that the results do not depend on the type of surgical approach but are closely related to the histology and location of tumours. Under the prerequisite of exact pre-operative definition of tumour location, unilateral approaches are advantageous for all kinds of spinal tumours especially for juxtamedullary benign tumours.

Adolescent↗
PubMed1989

Complications of anterior cervical discectomy without fusion in 450 consecutive patients.

The complications of anterior discectomy without fusion were analyzed on the basis of 450 consecutive cases treated surgically for degenerative disc disease. There was no death related to the procedure. The most common complication was a worsening of the pre-existing myelopathy. This occurred in 3.3%, including one case with severe medullary contusion. Wound infection developed in 1.6%. Additional radicular symptoms and wound haematoma, respectively, occurred in 1.3%; recurrent nerve palsy, Horner's syndrome, and respiratory insufficiency, respectively, in 1.1% of the cases. Epidural haematoma and instability of the cervical spine, respectively, occurred in 0.9%, nerve root lesion and aseptic spondylodiscitis, respectively, in 0.4%. There was one case each (0.2%) with a pharyngeal lesion, meningitis due to dural perforation, transient additional myelopathy, and epidural abscess. The results and the management of complications are discussed in relation to numerous previously published reports, including posterior procedures and anterior fusion techniques. Precise knowledge of all potential accidents and pitfalls related to the surgical procedure and of their aetiology may contribute to preventing failures. The rate of complications in this series has been reduced in the past years by better patient selection, by paying more attention to correct positioning of the patient during the operation, and by meticulous removal of all offending structures. Discectomy without interbody fusion is now considered to be a reasonably safe procedure with an acceptable operative morbidity and lack of mortality.

Adult↗
PubMed1989

Intracranial chondroma. Case report.

We present a rare case of intracranial chondroma originating from the falx cerebri. Diagnostic procedures and surgical management are discussed, with special reference to computed tomography, magnetic resonance imaging, and pathologic findings.

Adult↗
PubMed1989

Hemangioblastomas of the central nervous system. A 10-year study with special reference to von Hippel-Lindau syndrome.

The findings of a 10-year study (1976 to 1986) conducted in southwest Germany on hemangioblastomas (HBL's) of the central nervous system (CNS) are presented. During that period, 47 HBL's were diagnosed and surgically removed in 44 patients, with a good postoperative survival rate and prognosis. The majority (83%) of these tumors were located in the cerebellum. By thorough clinical examination of the patients and careful evaluation of their family background, it was found that 23% of the HBL patients were afflicted with von Hippel-Lindau syndrome. In addition to the CNS tumors, 14 neoplastic or similar lesions were detected in other tissues. These included angiomatosis of the retinae, pheochromocytomas, pancreatic cysts, renal cysts, and renal carcinoma. The diagnosis of von Hippel-Lindau syndrome was thus established in seven families. The authors suggest the need for a screening program for patients with HBL of the CNS which is designed to confirm or exclude ocular or visceral lesions associated with von Hippel-Lindau syndrome.

Adolescent↗
PubMed1988

Early aneurysm surgery: a 7 year clinical practice report.

One hundred and fifty patients with intracranial aneurysms, operated on consecutively in the early stage in our department, were re-evaluated retrospectively. Seven surgeons operated on 159 aneurysms in 150 patients. Seventy-nine percent of the patients were in grades I-III (scale of Hunt and Hess), 21% in grades IV-V. Seventy-one percent had a severe haemorrhage (classification of Fisher et al.), 21% had an intracerebral haematoma. Intraoperative CSF drainage was an almost indispensable tool while postoperative external drainage did not prove to be helpful in preventing vasospasm and/or hydrocephalus. Induced hypotension was abandoned in favour of temporary clipping. Thirteen percent of the patients suffered a permanent or fatal immediate postoperative deterioration, while 11% developed delayed neurological deficits. Five percent were related to vasospasms alone, they were all transient. Five percent had vasospasm combined with other complications. One of them had permanent and the other one fatal deficits. One percent deteriorated due to embolism or occluded vessels. The results improved with the introduction of the calcium channel blocker nimodipine, induced hypertension and transcranial Doppler sonographic control of the vasospasm. Patients in good preoperative condition had a good early outcome in 69%. The result was fair in 21% and poor in 4%, while 6% of the patients died. In the poor condition group 22% of the patients made a good, 13% a fair, and 59% a poor recovery, 16% of whom died.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Angiography↗
PubMed1988

Clinical long-term results of anterior discectomy without fusion for treatment of cervical radiculopathy and myelopathy. A follow-up of 164 cases.

Between 1976 and 1983, 251 patients underwent surgery for the treatment of cervical degenerative disc disease. Anterior microsurgical discectomy at one or more cervical segments without interbody fusion was performed in each case. 109 patients with radiculopathy and 55 patients with myelopathy were followed up clinically 1 to 8 years postoperatively. A soft disc lesion was found in 72, a hard disc lesion in 92 patients. Of all radicular symptoms and signs, brachialgia and motor deficits of the upper extremities showed the highest improvement rates. The medullary complaints were improved in 80%, the progression of the disease was arrested in 93% of myelopathic cases. An excellent or good long-term result was achieved in 82% of patients with radiculopathy and 55% of those with myelopathy. The outcome was best in cases with soft disc lesions, with monosegmental disease, in individuals under 50 years of age, and in patients with a sudden onset and a short duration of symptoms. These results are comparable with those obtained by other surgical methods.

Adult↗
PubMed1988

Haemodynamic changes in arteriovenous malformations induced by superselective embolization: transcranial Doppler evaluation.

To reduce the intraoperative and postoperative complications in patients who suffer intracerebral arteriovenous malformations (AVM's), the slow reduction of the shunt flow to a brain perfusion flow has been tried by the use of several methods: microsurgical techniques, selective and superselective embolization, intraoperative embolization, staged operation. The risk of re-bleeding and intraoperative oedema increases in AVM's with two or more feeders. Our policy was to exclude such AVM's by primary superselective embolization. If there was only a small residual angioma, we tried to remove this by microsurgical techniques. The haemodynamics in AVM's could be examined by measuring the blood flow velocities in the feeding arteries and in the other parts of the circle of Willis by transcranial Doppler sonography (TCD). Signs of haemodynamic effective embolization could be measured by the reduction of flow velocities. After exclusion of an AVM the velocities in the brain and feeding arteries decreased to below normal values in the first days after the operation. In the feeding arteries this was due to the fact that the arteries were enlarged so that the velocity must be decreased when there was normal volume flow. The combination of superselective angiography and microsurgical resection of the residual angioma seemed to be the best way to treat AVM's which are fed by more than two arteries and which are 3 or more cm in diameter. TCD investigations were used to measure the haemodynamic changes before and after angioma superselective embolization and microsurgical operation.

Cerebral Angiography↗
PubMed1987

Optical properties of human brain tissue, meninges, and brain tumors in the spectral range of 200 to 900 nm.

Considering the increasing use of lasers in neurosurgery and the increasing number of wavelengths of laser light becoming available, we evaluated optical properties between 200 and 900 nm of meninges, normal human brain tissue, and brain tumors. We used a two-beam spectral photometer with an integrating sphere as the measuring instrument. The material consisted of 13 brains and 1 specimen each of dura mater, falx, and arachnoid obtained at autopsy and 30 samples of brain tumors removed during operation. In tissue samples more than 5 mm thick, the relative levels of absorption and scattering were estimated from the relative level of reflection measured according to the Kubelka-Munk theory. In thin tissue slices, penetration depth was calculated according to Beer's law from measurements of reflection and transmission. Generally, in all tissues there was an increase of reflection, scattering, and penetration depth and a decrease of absorption from the ultraviolet up to the near infrared spectral range interrupted by the absorption bands of hemoglobin. Within the ultraviolet spectral range, no major differences of optical properties were observed. Within the visible and near infrared spectral range, white matter reflected most of the incident power and showed the lowest level of absorption and the shortest penetration depth. Low grade gliomas revealed optical properties similar to those of gray matter. In comparison with normal brain tissue, meningiomas and glioblastomas showed significantly higher levels of absorption calculated according to the Kubelka-Munk theory from reflection measurements in thick tissue samples, but also deeper penetration obtained from measurements of reflection and transmission in thin slices, especially within the near infrared spectral range.

Aged↗
PubMed1985

Possibilities and limits of the midline interhemispheric approach.

Based on experience in 17 children operated upon between 1978 and 1984, the possibilities and limitations of the interhemispheric parafalx approach to lesions of the anterior and posterior lateral ventricles and the third ventricle are described. The interhemispheric approach seems more advantageous than transcortical approaches since additional cortical and white matter lesions can be avoided. The limitations of visibility are the same as in transcortical approaches.

Adolescent↗
PubMed1985

Extradural and intradural microsurgical approaches to lesions of the optic canal and the superior orbital fissure.

Within 3 years, 34 patients with lesions of the posterior part of the orbit, the optic canal, and the superior orbital fissure were operated using different surgical approaches. The results on the functional and cosmetic outcomes were compiled. The pterional approach was shown to be the most useful one. It can be used in intradural as well as in extradural and combined operations. It allows an excellent view of basal cerebral structures as well as the frontal base of the skull. The operative results are dependent on the type and the location of the lesion, and, especially in meningiomas, on their relationship to the cavernous sinus.

Adult↗