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W J Bock

Publications and source records attributed to W J Bock.

At least 19 recordsLinked to original sources
PubMed1992

[Quality assurance--an important factor in the structure of medical management of the future].

Quality of medical practice has several prerequisites. A certain structural quality is essential to ensure good quality medical performance. Structural and performance quality both lead to result quality. Performance quality is dependent on well-working structures. With respect to neurosurgery a high level hospital organisation is required which allows equally qualified medical performance. Structure therefore has to attain a standard to stand up to quality assurance criteria. Next to hospital equipment structural quality requires sufficient staff capacity as well as unlimited neurosurgical access to technical equipment such as computerized tomography, MR, angiography and also intensive care under neurosurgical supervision. Quality assurance has been widely discussed in recent years. Measures to guarantee quality assurance, as required by federal law in Germany, are taking three different steps, first a model phase as a scientific study developing methods and observation, a second phase called study phase with wide effects and institution in various departments. In this phase the effectiveness of the procedure is tested and assured. In the third phase routine use is instituted. In quality assurance in neurosurgery phase two is presently tested, phase three is in preparation.

Clinical Competence↗
PubMed1991

[Total parenteral nutrition of neurosurgical patients following elective midline surgery].

The authors report on their results of total parenteral nutrition (TPN) which was performed in a group of 11 comatose patients following elective neuro-surgery of different midline lesions (e.g. tumours, aneurysms of the anterior communicating artery). Carbohydrates were administered from day 1 postoperatively in a dose of 18-24 kcal/kg BW/day. Amino acids were given as a commercially available 12.5% solution (1.4-1.83 g/kg BW/day). Daily routine laboratory values were measured as well as levels of total serum protein, albumin, prealbumin, and retinol-binding protein. Free amino acids in plasma were measured on the day of operation and on day 3, 5, and 7 postoperatively. Renal nitrogen loss was high with maximal values up to 30 gm/day. By TPN cumulative nitrogen balance remained positive until day 2 and was reduced to -61.8 g at the end of the study period. Short-lived serum proteins remained normal. Free FAA's in plasma increased steadily with their highest levels on day 5 and 7 (twice the normal range). Besides slight elevation of liver enzymes and mild hyperglycaemia, no severe changes were observed in routine laboratory parameters. The authors conclude that severe catabolism is a common feature in comatose patients after elective midline surgery and is comparable to catabolism following brain injuries. TPN is well indicated in this group as it preserves visceral protein levels and reduces nitrogen loss without severe side effects.

Adult↗
PubMed1991

Surgery of spinal tumours.

Otfrid Foerster's contribution to neurosurgery was the application of morphological and functional knowledge to the surgical therapy of neurological disease. Kuhlendahl coined the term of patho-biomechanics to explain and subsequently treat spinal pathology in a way still relevant to our surgery. The history of spinal surgery and its pioneers leads us from careful first indications to the classical problems of risks and benefit of tumour surgery in an around the spinal canal, extent of tumour resection and stability of the various spinal segments to modern techniques of intraoperative monitoring, microsurgery and stabilisation procedures. An overview of a multicentre study conducted by the Deutsche Gesellschaft für Neurochirurgie is presented. Some examples taken from our daily work are shown to illustrate the range of procedures in our spinal tumour patients.

Adult↗
PubMed1991

[MRT in syringomyelia--follow-up control after syringo-arachnoid shunt surgery with clinical correlation].

In 8 patients with syringomyelia, MR long-term follow-ups (observation period 25-46 months) were done after syringosubarachnoidal shunt operations. MR showed directly after surgery in 6 cases an extensive collapse of the syringomyelias and in 2 cases a lesser reduction of the diameter of the syrinx. During the subsequent course the size of the cavities increased again in 3 cases. The size of the syrinx visualised by MR did not correlate with the clinical status during the follow-up studies. This seems to point to an insufficient representation of the disease process by the morphological visualisation of the size of the syrinx.

Adult↗
PubMed1990

Continuous monitoring of cerebral tissue pressure in neurosurgical practice--experiences with 100 patients.

The authors present their experience with the use of continuous monitoring of cerebral tissue pressure (CTP) in a neurosurgical intensive care unit. The CTP was monitored in 100 patients with a variety of neurosurgical diseases. In 13 patients simultaneous recording of the ventricular fluid pressure (VFP) was carried out for up to 134 h. In 21 patients intrahemispheric gradients of CTP were recorded and in 66 patients CTP alone was recorded (59 supratentorial, 7 infratentorial). In general CTP monitoring gave excellent results with no additional risk to the patient and low costs for the monitoring system. The behaviour of CTP in various clinical conditions and the indications and limitations of CTP monitoring compared with VFP or epidural pressure monitoring are outlined. The authors recommend monitoring of VFP as the method of choice in ICP supervision. Continuous monitoring of CTP is the preferred method in the posterior fossa, after large craniectomies, for postoperative supervision following open surgery and in cases of narrowed ventricles.

Catheters, Indwelling↗
PubMed1989

Adjuvant intraarterial chemotherapy with nimustine in the management of World Health Organization Grade IV gliomas of the brain. Experience at the Department of Neurosurgery of Düsseldorf University.

A protocol with postoperative adjuvant intraarterial (ia) chemotherapy using nimustine (ACNU) was followed at the University of Düsseldorf (Federal Republic of Germany) after histologic confirmation of malignant glioma of the brain. The first iaACNU procedure was performed within 10 days of surgery, and immediately before postoperative irradiation. After radiotherapy further iaACNU courses were given. The study population consisted of 35 primarily treated malignant gliomas World Health Organization (WHO) Grade IV, i.e., glioblastomas (NIV). Of these tumors 11 showed early progressive disease (PD) (NIV primPD), whereas 24 had stable or responsive disease (NIV SD&RD). Seven patients with recurrent malignant gliomas WHO Grade IV (NIV recurrent) were also treated plus six patients with malignant gliomas WHO Grade III (NIII). Experience with 50 treated patients resulted from this study. The median survival time (MST) for the group NIV was 14.2 months; 41.0% of patients were long-term survivors. The MST for the group NIV primPD was 7.8 months; 9.1% of patients were long-term survivors. For the group NIV SD&RD a MST of 18.3 months and 66.7% of long-term survivors were determined. Patients with recurrent tumors on this treatment protocol had an additional MST of 6.1 months. The total MST after first surgery was 16.2 months. The incidence of complications was low. Systemic complications were infrequent or rare. Retinal disturbances were seen in two patients; leukoencephalopathy was not seen in our patients. In 10% of patients cerebral complications were found, which were irreversible in 2% of patients. Complications could not be assigned unequivocally to the nitrosourea. These results compare favorably with what is reported in the literature, demonstrate the potential value of iaACNU in the treatment of malignant gliomas WHO Grade IV, and should encourage the initiation of a randomized clinical trial of adjuvant iaACNU in the therapy of these tumors. The authors propose iaACNU as a valuable approach in the management of primarily diagnosed malignant gliomas WHO Grade IV, but cannot recommend the delay of iaACNU until the recurrence of a brain tumor.

Adult↗
PubMed1989

[Contrast medium enhanced MRT of tumors of the posterior fossa in children and adolescents].

The results of contrast-enhanced MR in 24 children and adolescents with tumours of the posterior cranial fossa are presented. During initial diagnosis, the majority of tumours showed intensive enhancement with improved demarcation from neighbouring structures. The solid component of a cystic tumour, even when small and not visible on the original scan, could be demonstrated in all cases by means of gadolinium-DTPA. Post-operatively, T2-weighted scans regularly showed areas of high signal strength at the margin of the resection; in the absence of a mass or demonstrable progression, the significance of this is uncertain. In these cases gadolinium-DTPA, because of the function of the blood-brain barrier, greatly increases accuracy in demonstrating residual or recurrent tumours.

Adolescent↗
PubMed1989

[MRT using gadolinium-DTPA in spinal intradural space-occupying lesions].

The results of contrast enhanced MRI in 36 patients with suspected spinal intradural tumours are described. All intramedullary tumors showed distinctive enhancement and solid tumors could be delineated clearly, even if they were not clearly visible on unenhanced scans. The differentiation between neoplasm and non-neoplastic syrinx was markedly improved. The sensitivity of MRI for demonstrating intradural extramedullary tumours was greatly improved by gadolinium DTPA and even small lesions or flat meningeal infiltrates could be visualised. In addition, gadolinium DTPA improved the delineation and localisation of larger lesions, even if they had already been seen on unenhanced images.

Adolescent↗
PubMed1989

Investigations of brain tumours with 99Tcm-HMPAO SPECT.

The cerebral uptake of 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) as measured with the use of single photon emission computed tomography (SPECT) was studied in 66 patients with various types of brain tumours and quantified by tumour-to-cerebellum ratios. The uptake of 99Tcm-HMPAO by gliomas and meningiomas showed wide ranges of values. There were no significant differences among primary malignant gliomas (0.75 +/- 0.27, n = 25), recurrent malignant gliomas (0.81 +/- 0.25, n = 14) and benign gliomas (0.77 +/- 0.21, n = 9). Compared to gliomas, meningiomas exhibited a significantly higher 99Tcm-HMPAO uptake (1.14 +/- 0.31, n = 13, p less than 0.001) while the remaining four patients with tumours of various histopathology showed a low 99Tcm-HMPAO uptake. Three of the 66 patients were scanned immediately and again 2 h after injection and they revealed a decrease in tumour activity. No changes in the pattern of uptake were observed in two patients with gliomas which were studied before and after intra-arterial chemotherapy, but a decrease in tumour uptake was found in the glioma patient who was studied before and after radiotherapy. The results obtained with 99Tcm-HMPAO SPECT are in agreement with those on regional cerebral blood flow (rCBF) in brain tumours reported in the literature.

Brain Neoplasms↗
PubMed1989

Early effects of intra-arterial chemotherapy in patients with brain tumours studied with PET: preliminary results.

In ten patients with malignant gliomas the regional cerebral metabolic rate for glucose (rCMRGlc) was studied with positron emission tomography (PET) using 2-18F-deoxyglucose (18FDG) before and within 1 to 7 days after intra-arterial chemotherapy with the nitrosourea derivative ACNU (iaACNU). Three patients were studied before and after two iaACNU courses and one patients before and after three iaACNU courses. The early effects of iaACNU on tumour rCMRGlc were highly variable and appeared to be more pronounced after the first course of iaACNU than in later iaACNU courses, i.e. more pronounced in untreated patients. Although there was no clear correlation between the change of rCMRGlc following the first course of iaACNU and the clinical outcome in this small group of patients, the patient with the most pronounced decrease of tumour metabolism (-16.5%) after the first course of iaACNU exhibited full tumour remission for 12 months, while the patient with the most pronounced increase of tumour metabolism (+65%) after the first course of iaACNU developed rapid tumour progression. The first results indicate that early effects of intra-arterial chemotherapy may be observed with 18FDG PET, especially following the first course of iACNU. Further studies are needed to evaluate the predictive value of such studies for therapy response.

Adult↗
PubMed1989

[Preoperative nutritional status of neurosurgery patients].

In a prospective trial anthropometric and biochemical data of 24 neurosurgical patients with primary intracranial tumors were measured to assess preoperative malnutrition in this special group of patients. In spite of starving because of invasive diagnostic procedures, high-dose dexamethasone therapy of peritumoral edema, and changes in food intake because of psychical alterations and repeated vomiting resulting from elevated intracranial pressure no abnormalities were found in the data measured. The authors conclude that in general preoperative malnutrition is absent in neurosurgical patients and preoperative nutrition to improve postoperative outcome is not indicated in this group.

Adult↗
PubMed1989

Principles of biological comparison.

The problems of comparative analyses in biology have been discussed, showing that a single comparative method does not exist. Several principles of comparison are elucidated, which include that comparisons do not have to possess a phylogenetic basis, can be horizontal or vertical, and can be genetic or nongenetic. Biological comparisons can be grouped roughly into historical and nonhistorical ones. Historical comparisons depend on the details of evolutionary theory, and include: (a) comparisons on which phylogenies and classifications are based; and (b) comparative studies using these phylogenies and classifications. Nonhistorical comparisons require pertinent nomological relationships between two or more variables, and include: (a) comparisons between variables used to elucidate these law-like relationships; and (b) comparisons in which unknown properties of one variable are deduced from the known properties of other variables - extrapolations made in biology.

Anatomy, Comparative↗
PubMed1988

Magnetic resonance (MR) imaging in the management of primary and secondary syringomyelic cavities, and of other cystic lesions of the spinal cord.

During the past three years 27 patients with medullary and/or brainstem cavities were examined with MRI at the Institute of Roentgenology, and we report the radiological MRI correlative findings. Five patients were operated: postoperative MRI examinations were compared with preoperative studies. Syringomyelia was present in 21 cases, syringobulbia in 2, and syringobulbomyelia in 4. Additional pathology such as the Arnold Chiari malformation or hydrocephalus was found at the craniospinal junction in 8 patients. Two instances of associated intraspinal tumours were noted too. In all cases the syringomyelic cavities involved the cervical cord and in most of them the lesion extended down to the thoracic or even lumbar level. Several patients were shown to have multilocular cavities. In the patients with syringomyelia a syringoarachnoidal shunting procedure was performed. This resulted in cyst collapse as proved by postoperative MRI examinations; neurological symptomatology was ameliorated too. Conventional radiological imaging with computed tomography (CT) and myelography was not as efficient as MRI in imaging syringomyelia. The extent of intramedullary cavities as well as the presence of associated pathology is best appreciated on sagittal MRI. The use of special surface coils clearly results in better image quality due to higher resolution. According to our experience MRI should be the primary examination in syringomyelia; myelography and CT are obsolete in the management of syringomyelia; the insertion of a syringoarachnoidal shunt is a convenient surgical procedure, resulting in clinical amelioration in most cases.

Adolescent↗
PubMed1988

Intrahemispheric gradients of brain tissue pressure in patients with brain tumours.

The authors report on 14 patients in whom cerebral tissue pressure was recorded after operation for brain tumours. Cerebral tissue pressure was recorded by a 5 French catheter with two microtransducers. The transducers were placed intraoperatively in the wall of the tumour cavity and in a distance of approximately 2.5 cm. Differences between both pressures from 4 to 28 mmHg were observed. They were higher in patients with glioblastomas and meningiomas than in patients with intracranial metastases. In 7 patients proximal tissue pressure was higher than distal. In 4 patients the contrary was observed. Discussing the literature the authors think intrahemispheric changes of brain water content, blood flow, and brain tissue elastance to be responsible for this phenomenon.

Adult↗
PubMed1988

Tomographic studies of rCBF with [99mTc]-HM-PAO SPECT in patients with brain tumors: comparison with C15O2 continuous inhalation technique and PET.

In 10 patients with malignant gliomas, the intracerebral distribution of [99mTc]-hexamethylpropylene-amine oxime [( 99mTc]-HM-PAO) was studied with single photon emission computed tomography (SPECT) in comparison with C15O2 steady-state inhalation technique to measure cerebral blood flow using positron emission tomography (PET). In all instances, the cerebral [99mTc]-HM-PAO distribution was comparable with the regional pattern of cerebral blood flow (rCBF) observed with PET. This was confirmed by a significant correlation of tumor to cortex and tumor to white matter ratios between these two experimental methods. However, the contrast between high and low activity regions in the SPECT scans was significantly less than that in the PET scans. Contrast enhancement of the SPECT scans was accomplished using a correction formula proposed by Lassen.

Brain Neoplasms↗
PubMed1988

[The energy consumption of patients with craniocerebral trauma and spontaneous intracranial hemorrhage in the early postoperative post-traumatic phase].

Indirect calorimetry was performed during the first five days after admission in 18 neurosurgical patients with isolated head - injuries (N = 7) and spontaneous intracranial hemorrhages (N = 11) to determine basal metabolic rates (BMR). In the study group each day BMR varied from 2143 +/- 636 kcal/day to 3371 +/- 1140 kcal/day. Most patients however showed BMR values between 2000 and 2500 kcal/day. Individually BMR values ranged from 60 to 340 percent of normal healthy individuals. Patients with isolated head - injuries showed significant higher metabolic rates than patients with spontaneous intracranial hemorrhages. The authors conclude that an caloric intake of 2000 to 2500 kcal/day is sufficient for parenteral nutrition and usually helps to avoid negative effects of hyperalimentation by overestimation of BMR in this special patient group.

Adult↗