Biomedical subjects
Publications and source records attributed to G Fries.
A one-pot reaction affords unsymmetrical 1,2-bis(phosphanyl)ethanes 2 and 1,2-arsanyl(phosphanyl)ethanes 3 from the cyclic sulfate 1 in high yield. Similarly, chiral 1,2-bis(phosphanyl)ethanes and 1,3-bis(phosphanyl)propanes could be obtained in enantiomerically pure form. R, R'=alkyl, phenyl.
Since 1910, when Lespinasse [73] in Chicago was the first surgeon to use an endoscopic device for the treatment of a neurologic disease, various methods of endoscopy have evolved into accepted diagnostic and therapeutic adjuncts of modern neurosurgery. Nevertheless, until recently technical shortcomings of the available endoscopes have prevented the widespread use of neuroendoscopy. However, now, at the end of the 20th century, endoscopes can be regarded as some of the most important instruments for the development of microneurosurgery into the 3rd millennium. The aim of this review of intracranial endoscopy in neurosurgery, which admittedly might not be completely objective in the authors' personal assessment of various endoscopic techniques, is first to depict the historical evolution of neuroendoscopy, second to describe the technical equipment used in intracranial endoscopic neurosurgery, third to characterize the most frequent endoscopic methods in brain surgery, and fourth to indicate how neuroendoscopy might develop in the near future. It will be shown that this ongoing evolutionary process in neuroendoscopy was only possible with the mutual influence of improved diagnostic techniques, increased microanatomical knowledge, refined neurosurgical instrumentation--especially the introduction of the surgical microscope, and endoscopic diagnostic and therapeutic strategies.
OBJECTIVE: Endoscopic third ventriculostomy (ETV) has been shown to be a sufficient alternative in the surgical treatment of occlusive hydrocephalus. To elucidate the ongoing discussion of timing, indication, and surgical technique, a retrospective analysis of 100 consecutive ETVs was conducted. METHODS: One hundred ETVs were performed in 95 patients (43 female and 52 male patients). Their age ranged from 3 weeks to 77 years (mean age, 36 yr). Hydrocephalus was caused by aqueductal stenosis in 40 patients, space-occupying lesions in 42, and intraventricular or subarachnoid hemorrhage in 8. One patient had postinflammatory hydrocephalus, and four patients had occlusive hydrocephalus of unknown origin. In 33 cases, surgery was performed using stereotactic guidance. RESULTS: ETV was accomplished in 98 of 100 cases. The overall success rate was 76%. Patients with benign space-occupying lesions and nontumorous aqueductal stenosis had the highest success rates, which were 95 and 83%, respectively. Complications were arterial bleeding in one case, venous bleeding in three cases, intracerebral bleeding in one case, and infection in one case. There were no permanent morbidities or mortalities. CONCLUSION: ETV is most effective in treating uncomplicated occlusive hydrocephalus caused by aqueductal stenosis and space-occupying lesions. ETV is still effective in two-thirds of the patients with previous infections or intraventricular bleeding. Patients who have previously undergone shunting and who have occlusive hydrocephalus should undergo ETV at the time of shunt failure, with immediate ligation or removal of the shunt device. In selected cases of distorted anatomy or impaired visual conditions, stereotactic guidance is helpful.
We report the case of a patient who developed a large brain abscess after neurosurgery. Cerebrospinal fluid from the abscess drainage yielded Abiotrophia adiacens-specific PCR products and microorganisms that were identified by conventional microbiological methods and by 16S ribosomal DNA analysis as Abiotrophia adiacens, which was formerly classified as a member of nutritionally variant streptococci.
L-tryptophan is produced at the AMINO GmbH (Frellstedt, FRG) via biocatalytical condensation of the amino acid L-serine with indole. As a biocatalyst, tryptophan synthetase is used which is produced in high activities by a natural mutant Escherichia coli strain. The enzyme mechanism and specificity and the individual process-parameters for the biotransformation procedure are explained as well as the purification process of educts and products. This includes a detailed description of the quality control of educts, intermediates and final product. The active ingredient L-tryptophan is subsequently used by AMINO's subsidiary company esparma GmbH to produce and distribute the pharmaceutical Lyphan. The quality management system and the production procedure for Lyphan are described and discussed.
In 72 patients with acute subarachnoid haemorrhage (SAH) the relationship between the amount of subarachnoid blood clots detected by initial cranial computed tomography (CCT) up to 48 hours after bleeding and the later development of vasospasm, established by blood flow velocity measurement with transcranial Doppler ultrasound (TCD) was investigated. The serial Doppler examinations started within the first 72 hours after SAH and were carried out every second day up to three weeks. Each Doppler recording was accompanied by a neurological examination. Patients classified as Hunt and Hess grade V were excluded from the study. All patients with remarkable brain oedema in CCT or with intracranial pressure above 25 mmHg were also excluded. Because of the well known age-dependence of vasospasm after SAH, two age groups were formed. A statistically significant correlation (p > 0.05) between blood flow velocities and blood load after SAH was not found. The mean age of the investigated 72 individuals was 48.9 years (14 up to 76 years). 47 patients were younger than 56 years. Linear regression analysis indicated a correlation with a quite low significance level (r = 0.350, p < 0.025) between TCD blood flow velocities and blood load in CCT in these younger subjects. No significant correlation (p > 0.05) between these two variables could be established in the 25 patients older than 55 years. In a second step an intra-individual comparison of side-to-side differences in TCD and CCT was made. There were no significant differences in blood flow velocities between subjects with or without side-to-side differences in cisternal blood load. It is concluded that the amount of blood visible on initial CCT after SAH is not a powerful predictor of cerebral blood flow velocities measured by TCD.
BACKGROUND: Anterior surgical approaches to the base of the brain have always required relatively large craniotomies, most larger than the lesion itself. Especially in aneurysm surgery, the size of the lesion is not always proportionate to the extent of brain exposure. The improvement of surgical techniques and diagnostic imaging, as well as the introduction of neuroendoscopy and new surgical instruments, enable us now to treat various intracranial lesions through small keyholes. In particular, cerebral aneurysms, because of their anatomic characteristics, are apt to be treated by the keyhole approach. The supraorbital keyhole approach has the broadest field of indications, although its technical aspects have not yet been evaluated. METHODS: The concept and technique of the supraorbital keyhole approach are presented in detail. We conducted a retrospective study in which we evaluated the technical aspects of the supraorbital keyhole approach considering the indications, limitations, and complications of this approach as well as new instrumentation in surgery of supratentorial aneurysms. RESULTS: The use of 139 supraorbital keyhole approaches for 197 aneurysms is described. Multiple aneurysms have been treated by one approach in 38 patients. Clipping of the aneurysm was performed in 94% and wrapping in 6% of patients. Eighteen aneurysms were contralateral to the approach. In four patients, intraoperative accidental aneurysm rupture occurred. There were no approach-related complications. CONCLUSIONS: The supraorbital keyhole approach offers equal surgical possibilities with less intraoperative accidental rupture and less approach-related morbidity as conventional approaches in the treatment of supratentorial aneurysms.
RATIONALE: The evolution of neurosurgical techniques indicates the effort to reduce surgery-related traumatization of patients. The reduction of traumatization contributes to better postoperative outcomes. The improvement of diagnostic imaging techniques facilitates not only the precise localization of lesions but also the accurate determination of topographical relations of specific lesions to individual anatomic variations of intracranial structures. This precision of diagnostic imaging should be used to perform individual surgical procedures through so-called keyhole approaches. Keyhole craniotomies are afflicted with a reduction of light intensity in the depth of the operating field, and they provide rather narrow viewing angles. Thus, objects located directly opposite the approach entrance are more visible than those in the shadow of the microscope beam. These two deficiencies of keyhole craniotomies can be compensated for by the intraoperative use of rigid rod lens endoscopes, the shaft of which remains easily controllable through the surgical microscope. CONCEPT: Endoscope-assisted microsurgery, like all routine microsurgical procedures, is performed with both hands; the endoscope is fixed in its desired position via a mechanical arm to the headholder. Because of their superior optical quality and maneuverability, only rigid lens scopes are used for endoscope-assisted brain microsurgery. There are five ways of observing the endoscopic and microscopic images at the same time: 1) observation of the microscopic image through the oculars of the microscope and observation of the endoscopic image on a video screen placed in front of the surgeon, 2) observation of the microscopic image through the oculars of the microscope and display of the endoscopic image on a head-mounted LCD screen, 3) projection of both microscopic and endoscopic images on one screen in a picture-in-picture mode, 4) projection of both microscopic and endoscopic images into specially designed microscope oculars, and 5) transmission of both microscopic and endoscopic images into a head-mounted LCD screen. DISCUSSION: With the knowledge of almost all individual anatomic and pathoanatomic details of a specific patient, it is possible to target the individual lesion through a keyhole approach using the particular anatomic windows. As the light intensity and the depiction of important anatomic details are improved by the intraoperative use of lens scopes, endoscope-assisted microsurgery during keyhole approaches may provide maximum efficiency to remove the lesion, maximum safety for the patient, and minimum invasiveness.
OBJECTIVES: Microsurgical techniques and instruments that help to reduce intraoperative retraction of normal intracranial neuronal and vascular structures contribute to improved postoperative results. To achieve sufficient control of the operating field without retraction of neurovascular components, the resection of dura and bone edges is frequently required, which, on the other hand, increases operating time and operation-related trauma. The use of endoscopes may help to reduce retraction and, at the same time, may help to avoid additional dura and bone resection. The aim of this study is to describe the principles on which the technique of endoscope-assisted brain surgery is based, to give an impression of possible indications for endoscope-assisted microsurgical procedures, and, with illustrative cases, to delineate the advantages of endoscopes used as surgical instruments during microsurgical approaches to intracranial lesions. METHODS: During a period of 4.5 years, 380 microsurgical procedures were performed as endoscope-assisted microneurosurgical operations. This surgical series was analyzed for time of surgery, usefulness of intraoperative endoscopy, and complication rates. Lens scopes with viewing angles of 0 to 110 degrees and with diameters of 2.0 to 5.0 mm as well as newly designed "viewing dissectors" (curved, rigid fiberscopes) with diameters of 1.0 to 1.5 mm connected to a video unit were used as microsurgical instruments. The positioning of the endoscopes was achieved by retractor arms fixed to the Mayfield headholder. Thus, the surgeon was able to perform customary microsurgical manipulations with both hands under simultaneous endoscopic and microscopic control. RESULTS: The lesions treated with endoscope-assisted microsurgery comprised 205 tumors, 53 aneurysms, 86 cysts, and 36 neurovascular compression syndromes. Eighty-nine of these lesions were localized in the ventricular system, 242 in the subarachnoid space or intracerebral, and 49 in the sella. Endoscope-assisted microsurgery was advantageous to reduce the size and the operation-related tissue trauma of approaches to lesions within the ventricular system, in the brain tissue as well as in the subarachnoid space at the base of the brain. Using less retraction during tumor removal, the visual control of retrosellar, endosellar, retroclival, and infratentorial structures was improved. Video-endoscope instrumentation was especially helpful during procedures in the posterior cranial fossa and at the craniocervical junction. It allowed for inspection of channels and hidden structures (e.g., the internal auditory meatus, the ventral surface of the brain stem, the ventral aspect of root entry zones of cranial nerves, the content of the foramen magnum, and the upper cervical canal), both without retraction and without resection of dura and bone edges. Endoscope instrumentation during surgery for large or giant aneurysms was useful to dissect perforators on the back side of the aneurysms and to control the completeness of clipping. CONCLUSION: Although the results reported herein cannot be compared directly with those of exclusive microsurgical procedures performed during the same period of time, videoendoscope-assisted microsurgery can be recommended as a time-saving, trauma-reducing procedure apt to improve postoperative outcomes.
OBJECTIVE: The vicinity of carotid-ophthalmic aneurysms to the roof of the cavernous sinus, to the anterior clinoid process, and to the optic nerve or the optic chiasm requires well-defined surgical techniques. Although microsurgical techniques with ipsilateral direct approaches to these aneurysms have been described in detail, studies about contralateral strategies for the microsurgical treatment of carotid-ophthalmic aneurysms are rare and are mainly confined to case reports. The aim of this study is to describe how to decide on the ipsilateral and contralateral microsurgical approaches to such aneurysms and to demonstrate the surgical techniques for the ipsilateral and contralateral exposure of carotid-ophthalmic aneurysms. METHODS: In a series of 51 patients with 58 aneurysms of the ophthalmic segment of the internal carotid artery, nine patients with 10 aneurysms (4 large aneurysms, 6 small aneurysms) were treated via a contralateral microsurgical approach after careful preoperative planning. Preoperative planning was based on the analysis of clinical and radiographic data, including cranial computed tomography, magnetic resonance imaging, magnetic resonance angiography, and conventional cerebral angiography. RESULTS: The postoperative results were good in 38 (75%) of the patients, fair in 2 (4%), and poor in 3 (6%); 8 (15%) of the patients died after surgery. The postoperative follow-up was 4 months to 10 years. Postoperatively, 15 of 19 patients with uni- or bilateral visual deficits or visual field defects improved, 3 of the 19 patients experienced postoperative impairment of visual function, and 1 of the 19 patients had an unchanged visual field deficit. Visual impairment or unchanged visual function was observed in patients who underwent ipsilateral approaches, which was possibly caused by inappropriate intraoperative retraction of the optic nerve or chiasm. In all patients presenting with preoperative visual deficits who were treated via contralateral approaches, visual function improved in the postoperative course. CONCLUSION: Giant carotid-ophthalmic aneurysms that are eligible for surgical treatment as well as small and large aneurysms dislocating the optic nerve or the chiasm superomedially or medially should be approached via ipsilateral craniotomies. It is recommended that small and large aneurysms of the carotid-ophthalmic segment originating medially, superomedially, or superiorly, displacing the optic nerve or the chiasm superiorly, superolaterally, or laterally, be approached via contralateral craniotomies.
50 meningohypophyseal trunks of the intracavernous internal carotid artery were studied in 25 human cadavers. Special attention was given to the main variations of branching patterns of this trunk. The dorsal meningeal arteries were found in all cases and three typical variations were observed in their origins and courses: a prominent medial branch (52%), a bifurcating type (38%) or a single lateral branch was present (10%). The tentorial artery of Bernasconi-Cassinari arised as a single branch in 64% of the cases, while in 36% two or more branches took a direct origin from the main trunk. The inferior hypophyseal artery was prominent in 82% of the cases. The inferolateral trunk had a common origin with the meningohypophyseal trunk in 8% of our dissections. A large number of anastomoses between these vessels was observed. As a number of tumorous and vascular pathologies, which can be treated with microsurgical techniques, take their origin from the cavernous sinus, the knowledge of the smaller vessels arising from the intracavernous internal carotid artery as well as their main variations is important.
A preclinical cadaver study was performed to develop the technique of biportal neuroendoscopic dissection in the subarachnoid space of the basal cisterns and to test the feasibility, utility, and safety of this new technique. In 23 fresh post-mortem adult human cadavers and 2 formalin-fixed adult human head specimen a total of 33 biportal endomicrosurgical dissections into and within the basal cisterns were carried out. Following suction of cerebrospinal fluid from the subarachnoid space 0 degree-, 30 degrees-, and 70 degrees-lens-scopes (Aesculap AG, Tuttlingen, Germany) with outer diameters of 4.2 mm and trochars with outer diameters of 5 to 6.5 mm were introduced into the surgical field. 6 different endoscopic routes to the basal cisterns and a total of 10 different combinations of these approaches for biportal endoneurosurgery could be described, but it was found that not all of them were useful and safe. The transventricular approach to the prepontine cisterns through the foramen of Monro and the floor of the third ventricle, biportally combined with a subfrontal or a subtemporal approach, turned out to be not safe enough as it was accompanied by traumatization of the fornix at the interventricular foramen and of the hypothalamus at the level of the tuber cinereum due to relaxation and caudal shift of the brain following suction of cerebrospinal fluid to clear the basal cisterns for the subfrontal or subtemporal approaches. Useful and safe endomicrosurgical approaches to the basal cisterns were: 1st subfrontal, either epidural or intradural, 2nd subtemporal, either anterior or posterior, and 3rd frontal interhemispheric. Various biportal combinations of these approaches are estimated to be feasible, useful, and safe enough to be performed during microsurgical procedures in the operating room. The biportal endomicrosurgical strategy allows for effective and safe dissections within the subarachnoid spaces of the basal cisterns. The tip of the microinstruments as well as the neighboring anatomical structures can be nicely controlled at angles of about 60 degrees to 180 degrees depending on the viewing angles of the scopes used and depending on the individual shape of the head. A variety of microsurgical instruments has been tested. A number of these will have to be redesigned for this new technique. Regions suitable for biportal neuroendoscopic subarachnoid preparations are the olfactory groove, the prechiasmatic cistern, the region of the optic chiasm, the entire suprasellar area, parts of the parasellar area, the pre- and perimesencephalic cisterns, and the prepontine cistern.
The osteofibrous space underneath the dura mater of the dorsoclival area was studied with respect to the arterial branches arising from the internal carotid artery at this level. Special attention was given to the main variations of branching and anastomosing patterns found in this area. Our results indicate that the meningohypophyseal trunk is the main supplier of the dorsoclival area. The dorsal meningeal artery was present in all cases. In the course of this vessel three main variations were observed. The inferior hypophyseal and the tentorial artery also contributed to the arterial supply of this region. A large number of anastomoses between the internal and external carotid artery was present as well. Because of the refinement of microsurgical and interventional techniques pathological lesions like tumors and vascular malformations of the dorsoclival area are frequently accessible. The knowledge of the microvascular anatomy of the clivus and the dorsum sellae is important as the rich collateral network found in this area may contribute to the arterial supply of pathological lesions arising here.
During the years 1985 to 1992, we encountered 59 patients with meningiomas involving the space of the cavernous sinus. In 29 of these patients, meningiomas were primarily located within the space of the cavernous sinus and were operated on without mortality and with low morbidity. A small subtemporal surgical approach was favored, which allowed initial tumor resection from the posterior aspect, where the Parkinson's triangle is wide, thus avoiding the additional morbidity of large-scale approaches. According to the relationships of the all-important cranial nerves passing within the lateral wall of the cavernous sinus, we divided the primary intracavernous meningiomas into four types, which reflected not only the preoperative cranial nerve deficit but also the feasibility of surgical resection. Cranial nerve function deteriorated after operations in 14% of oculomotor nerves, in one abducent nerve, in 58% of trochlear nerves, and in 21% of trigeminal nerves. We encountered improvement of function in 43% of oculomotor nerves, in 50% of abducent nerves, and in approximately 30% of the second and third but in only 7% of the first branches of trigeminal nerves. There was no improvement in trochlear nerve function. Improvement of oculomotor nerve function was observed only in moderately impaired nerves, which indicates that surgery should be undertaken early to preserve or improve oculomotor nerve function.
Monocytes/macrophages frequently infiltrate malignant gliomas and play a central role in the tumor-associated immune response as they process tumor antigen and present it to T-lymphocytes. Findings have accumulated that peripheral blood monocytes leaving the cerebral circulation become microglial cells and vice versa and that monocytes/macrophages may stimulate malignant tumor growth by some unknown mechanism. Most malignant gliomas express growth factor receptors, for example epidermal growth factor receptor (EGFR). The aim of this study was to determine whether peripheral blood monocytes of glioma patients release EGF, the appropriate ligand of gliomacell membrane-bound EGFR. Long-term cultured peripheral blood monocytes from 14 patients with malignant gliomas were compared to those from 12 controls (seven with nontumorous disease and five healthy individuals). Using an enzyme-linked immunosorbent assay for EGF, the EGF content of cell culture supernatants was determined at Days 7, 21, and 100 of culture. The EGF content (mean +/- standard error) of supernatants was 5.9 +/- 0.2 pg/ml/10(3) glioma monocytes versus 1.3 +/- 0.1 pg/ml/10(3) control monocytes at Day 7 of culture, 22.9 +/- 0.8 pg/ml/10(3) glioma monocytes versus 1.8 +/- 0.9 pg/ml/10(3) control monocytes at Day 21 of culture, and 23.4 +/- 0.7 pg/ml/10(3) glioma monocytes, and below detection levels for control monocytes at Day 100 of culture. Steroid treatment of glioma patients did not influence the EGF release of cultured monocytes. These data indicate that glioblastoma-associated peripheral blood monocytes may be distinct from those of healthy individuals. Moreover, this study indicates that subtypes of glioma-associated peripheral blood monocytes may support immunosuppression and promote growth of malignant glioma by releasing unusually high amounts of EGF.
When operating on deep-seated cerebral aneurysms, the surgeon's visual control of clip application may be impaired by the clip holder unless adjacent structures are retracted. To improve visual control and reduce the necessity for retraction, the senior author (A.P.) developed a new concept: an aneurysm clip with an inverted-spring mechanism. The clip has two jaws that point away from the clip blades. The jaws of the clip holder articulate with the inner side of the clip jaws. By distending the jaws of the clip holder the blades of the clip are opened and vice versa. Thus the visual field increases while the clip application is proceeding. This instrumentation is useful, especially in cases of deep-seated aneurysms arising from the posterior circulation and in multiple aneurysms. In these latter cases even lesions located contralaterally could be reached with good visual control.
A retrospective analysis was undertaken to determine whether cerebral vasospasm following subarachnoid haemorrhage (SAH) correlates with the age of patients. For at least 3 weeks after bleeding 80 subjects underwent very close follow-up with clinical examination and transcranial Doppler records of the blood velocities within the basal cerebral arteries. Firstly a correlation between measured maximal mean blood flow velocities and age was made. Secondly, according to their age and the maximum of recorded mean velocities (v), the patients were divided into groups as follows: age 55 years or less, age more than 55 years; and maximum velocity v1 < 90 cm/s, 90 cm/s < v2 < 120 cm/s, 120 cm/s < v3 < 160 cm/s, v4 > 160 cm/s. There was a significant correlation of the measured maximum mean velocities and the age of the patients (r = -0.525, p < 0.01). With regard to the velocity groups there was a significant (chi-squared statistic for contingency tables, p < 0.01) difference between both age-groups: 32% (n = 18) of the younger fell into group v4 with maximum mean velocities of more than 160 cm/s, but none of the older had such. Vice versa, 63% (n = 15) of the older compared with only 14% (n = 8) of the younger fell into group v1 with maximum mean velocities of less than 90 cm/s. Clinical follow-up also depicted differences between both age groups. 13 of 18 younger patients with maximum mean velocities > 160 cm/s exhibited symptomatic vasospasm with a delayed neurological deficit. This typical course did not occur in the older age group.(ABSTRACT TRUNCATED AT 250 WORDS)
Interleukin-1 (IL-1) plays a controversial role in the immune response. Besides its activation of immune cells and juvenile central nervous system cells, monocyte-derived IL-1 may be able to stimulate the malignant transformation and proliferation of glial brain tumor cells expressing IL-1 receptors. The aim of this study was to determine the growth pattern and the IL-1 beta release of long-term cultured peripheral blood monocytes of glioma patients. At 6- to 7-day intervals, the vital monocytes, characterized by CD14 immunophenotyping, were counted. By the use of a specific IL-1 beta enzyme-linked immunosorbent assay, the IL-1 beta content of monocyte culture supernatants derived from 13 subjects with glioma and from 12 controls were compared at Days 7, 21, and 100 of culture. Cell clusters of monocytes derived from glioblastoma patients survived more than 250 days in culture, whereas control monocytes survived only up to 114 days. The IL-1 beta release of glioma-associated peripheral blood monocyte cultures was about 50 times higher as compared with control monocyte cultures. Dexamethasone treatment at the time of blood sampling and recurrences of the gliomas did not influence the increase in the IL-1 beta expression of glioma monocytes. It seemed that at least subsets of glioma-associated blood monocytes, although they had been removed from the circulation, remained activated for a long period of time. We conclude that increased IL-1 beta production of glioma-associated peripheral blood monocytes and their longevity in vitro may be features of aberrant immune cell subsets. In future studies, the exact phenotyping of monocyte subsets will be mandatory.