Biomedical subjects

V Seifert

Publications and source records attributed to V Seifert.

At least 55 records · Page 3Linked to original sources

PubMed2001

Open MRI-guided microsurgery of intracranial tumours in or near eloquent brain areas.

OBJECTIVES: Preservation of brain function while maximizing resection is the main aim of brain tumour surgery. The purpose of this study was to evaluate the efficacy of intra-operative magnetic resonance imaging to preserve brain function in patients with tumours in or near eloquent brain areas. METHODS AND MATERIAL: Between August 1997 and January 1999 fifty-eight craniotomies for intracranial tumours or vascular malformations have been performed at the University of Leipzig using a 0.5 T superconducting MR system "SIGNA SP" (General Electric Medical Systems, USA). In 32 of these patients (15 male/17 female) with intracranial tumours, located in or near eloquent brain areas (sensorimotor cortex/speech center), 34 craniotomies were performed using the image guidance of the interventional MRI. RESULTS: Using intra-operative MRI criteria, complete tumour removal could be achieved in 28 (82%) of 34 procedures. In 3 patients only subtotal tumour removal was possible, because the residual tumour was not visible on the intra-operative MR images, but could be identified on early diagnostic follow-up MR-scans. In 3 patients, incomplete tumour resection was performed in order to avoid neurological impairment. In these patients intra-operative MR-images revealed residual tissue abnormalities involving or encroaching on deep brain structures or motor/language cortex. Pre-operative neurological status was unchanged in 24 patients (70%), worsened in 4 patients (12%) and improved in 6 patients (18%). CONCLUSIONS: Intra-operative MRI is helpful for navigation as well as to demonstrate the tumour margins to achieve a complete and safe resection of intracranial lesions located in or near eloquent brain areas. It enables an image based functional monitoring of the brain which is critical for motor, sensory or language function. Complications related to the surgical procedure are reduced and the risk of neurological deterioration due to tumour removal and postoperative complications is minimized.

Adult↗

PubMed2001

Management-related morbidity and mortality in unselected aneurysms of the basilar trunk and vertebrobasilar junction.

OBJECTS: To analyze the management-related morbidity and mortality in unselected aneurysms of the basilar trunk and vertebrobasilar junction. The secondary objective was to investigate the factors associated with favourable or unfavourable surgical outcome in order to define subgroups for surgical and endovascular treatment. METHODS: 24 consecutive patients with aneurysms of the basilar trunk and vertebrobasilar junction were included in this study. They comprised 2.7% of all aneurysms treated during the study period between 1990 and 1997. 22 patients presented with acute subarachnoid hemorrhage (SAH) and 2 patients with symptoms of brainstem compresssion. All patients were managed using a standard protocol including surgery at the earliest possible moment, aggressive tripe-H therapy in patients with symptomatic vasospasm and mandatory follow-up angiography. 23 patients underwent surgical clipping and one patient endovascular coiling of the aneurysm. 12 patients had an excellent outcome. 6 patients had a good outcome, resulting in a total of satisfactory outcomes in 18 patients (75%). 4 patients (17%) had moderate to severe deficits. Two patients died (8%). Both patients had fusiform basilar trunk aneurysms. Good or excellent outcome was observed in 7 of 8 patients with aneurysms of the vertebrobasilar junction, 13 of 14 patients with moderate or minor SAH or without SAH (Fisher grade 0 to 2) and all patients with small sized aneurysm (n = 6). Factors mostly associated with poor outcome or death after surgical treatment were aneurysm location at the basilar trunk, large aneurysm size or fusiforme aneurysm type and severe SAH. CONCLUSIONS: Location, aneurysm size and the severity of SAH may help to predict the subgroup which highly benefits from surgical clipping of these rare vascular lesions.

Adult↗

PubMed2001

The risk of haemorrhage associated with early postoperative heparin administration after intracranial surgery.

BACKGROUND: To analyse the rate of postoperative haemorrhage during a 4-year period of early postoperative administration (< 24 hours) of fractionated heparin plus compression stockings in a large cohort of patients undergoing intracranial surgery. METHOD: A total of 1564 patients who underwent intracranial surgery at our institution were included in our study. 1197 of the 1564 patients (77%) had major intracranial surgery (group 1). Group 2 was made up of 367 patients in whom ventriculoperitoneal shunting or external ventriculostomy was performed (minor intracranial procedures). All patients were investigated retrospectively for the occurrence of major postoperative haemorrhage confirmed by CT scanning and requiring surgical evacuation. The protocol for prophylaxis of thrombo-embolic events included early (< 24 hours) postoperative fractionated low-dose heparin (3 x 5000 IE subcutaneously) until discharge plus intra- and postoperative compression stockings. FINDINGS: Major postoperative haemorrhages were observed in 31 of the 1564 patients (2.0%). In three patients, the haemorrhage occurred on the day of surgery before the administration of heparin. The haemorrhage rate of patients receiving heparin was 1.8% (28/1564). All haemorrhages occurred in patients undergoing major intracranial procedures (group 1; 31/1197; 2.6%). There was no haemorrhage in minor intracranial procedures (group 2; 0/367; 0%). INTERPRETATION: Although retrospective, this is to date the largest study supporting the concept of postoperative pharmacological thrombo-embolic propylaxis in patients undergoing intracranial surgery. The question as to whether pharmacological prophylaxis is beneficial for a given patient can only be answered by weighing the risk reduction of thrombo-embolic events against the risk increase of postoperative haemorrhage associated with different surgical procedures and heparin protocols.

Adolescent↗

PubMed2001

Intervertebral disc calcification in childhood--a case report and review of the literature.

The authors report the case of a 10-year-old girl with intervertebral disc calcifications from the levels C6/C7 to Th1/Th2, presenting with a herniated calcified intervertebral disc at the C7/Th1 level, causing spinal cord compression with subsequent progressive paresis and sensory loss of her left leg. After anterior cervical discectomy and fusion the neurological deficits completely resolved within 2 weeks. It can be concluded that calcification of an intervertebral disc is a rare syndrome in childhood, causing progressive neurological deficit only in a few reported cases. Although the treatment of choice is conservative, surgery is required in patients who develop progressive neurological deficit.

Calcinosis↗

PubMed2001

Rivet-like titanium clamp fixation of cranial bone flaps during open magnetic resonance-guided neurosurgery.

A new implant technique for bone flap fixation after magnetic resonance image-guided neurosurgical procedures in the first vertical open 0.5T MRI scanner is described. Between May 1998 and December 1998 cranial bone flap refixation was performed in 20 patients using rivet-like titanium cranial bone flap fixation clamps. In all cases, a safe and solid refixation of the bone flap was achieved. Intraoperative and postoperative MRI quality was not influenced. Rivet-like titanium clamp bone fixation is a safe procedure which can be easily performed under the special circumstances during neurosurgical operations with interventional MRI.

Humans↗

PubMed2001

Inhibition of endothelin-converting enzyme activity in the rabbit basilar artery.

OBJECTIVE: Endothelin (ET)-1 may be involved in the regulation of cerebrovascular resistance under pathological conditions, most notably during the development of vasospasm after subarachnoid hemorrhage. Blocking ET-converting enzyme activity may be a promising approach to the prevention of cerebral vasospasm after subarachnoid hemorrhage. METHODS: In this study, the effects of several putative ET-converting enzyme inhibitors were investigated after intracisternal application in rabbits, to inhibit basilar artery contractions induced by big ET-1 (2 x 10(-6) mol/L). RESULTS: In the group pretreated with [D-Val22]big ET-1[16-38] (2 x 10(-5) mol/L) (n = 8), the angiographically measured diameter of the basilar artery changed from 0.63 +/- 0.12 mm to 0.66 +/- 0.12 mm. In the control group (n = 8), the diameter of the basilar artery decreased from 0.71 +/- 0.13 mm to 0.57 +/- 0.15 mm. These results corresponded to an increase in vessel diameter of 5 +/- 10% in the treatment group and a decrease in vessel diameter of 20 +/- 16% in the control group (P = 0.014). In the group pretreated with captopril (2 x 10(-4) mol/L) (n = 8), the angiographically measured diameter of the basilar artery changed from 0.64 +/- 0.11 mm to 0.71 +/- 0.10 mm. These results corresponded to an increase in vessel diameter of 14 +/- 19% in the treatment group, compared with a decrease in vessel diameter of 20 +/- 16% in the control group (P = 0.014). CONCLUSION: These results demonstrate that [D-Val22]big ET-1[16-38] and captopril act as highly potent ET-converting enzyme inhibitors, affecting big ET-1-induced contraction of the rabbit basilar artery.

Animals↗

PubMed2001

Magnetic resonance imaging--guided biopsies of the petrous apex and petroclival region.

OBJECTIVE: To analyze the advantages in safety and precision of biopsies of the petrous apex and petroclival region using open magnetic resonance imaging (MRI). SETTING: The University of Leipzig Medical Center. PATIENTS: Biopsies were taken in 13 patients with tumors of the petrous apex and petroclival region. INTERVENTION: With the patient in the 0.5-T intraoperative MRI system (Signa SP; General Electric Medical Systems, Boston, MA, U.S.A.), biopsies were taken from the petrous apex and the petroclival region under imaging control by transseptal, transsphenoidal access. The region of interest was approached with a virtual pointer (Flashpoint Position Encoder; Image Guided Technologies, U.S.A.) and marked with a gadolinium-filled pointer. RESULTS: In all patients, the authors obtained enough tissue for histologic study, which also proved to be the suspected tumor. One patient had a bone cyst, another had a malignant lymphoma, and another two a cholesterol granuloma originating from the petrous apex. Three other patients had metastases (carcinoma of the breast, bronchial carcinoma, and unknown origin). Three patients had a meningioma, and another three a chordoma. The authors did not see any postoperative complications. CONCLUSIONS: In the authors' experience, the transsphenoidal access is favorable for approaching and sampling lesions of the petrous apex and the petroclival region. This route, however, is disadvantageous because the course of the internal carotid artery and the brainstem narrow the surgical space to the petrous apex. Open MRI in these cases is very useful because it allows a safe approach to the tumor by navigation and by visualizing the anatomic structures in real-time imaging.

Adult↗

PubMed2001

Median nerve compression caused by a venous aneurysm. Case report.

A rare case of peripheral-nerve compression in the upper arm caused by a spontaneous venous aneurysm is reported. The apparent dysfunction of the median nerve led to various vain surgical explorations of the nerve at different levels. The real localization of nerve entrapment was identified by a thorough clinical examination, and sonography yielded a correct diagnosis. Surgical resection of the venous aneurysm resulted in complete relief of pain. To the authors' knowledge, this is the first report of a spontaneous venous malformation in the upper arm causing focal neuropathy.

Adult↗

PubMed2001

Acute posttraumatic spinal cord herniation. Case report and review of the literature.

Transdural herniations of the spinal cord are rare, and those occurring acutely after a spinal cord injury (SCI) are particularly unusual. In this report, the authors present the case of acute posttraumatic spinal cord herniation in a patient who sustained severe polytraumatic injuries. The clinical manifestations were acute flaccid paralysis of the right leg and rapidly progressive sensorimotor deficits of the contralateral leg. The herniation was surgically reduced. Postoperatively left leg paralysis was completely resolved. The authors review the pertinent literature, and suggest that, with regard to another underlying pathophysiological mechanism, cases of acute posttraumatic spinal cord herniation should be differentiated from those "posttraumatic" cases in which herniation of the spinal cord occurs years or even decades after the traumatic event. To the best of the authors' knowledge, only one similar case has been previously reported. They conclude that acute posttraumatic spinal cord herniation should be included in the differential diagnosis of acute neurological deterioration after SCI.

Adult↗

PubMed2001

Gross-total surgery of supratentorial low-grade gliomas under intraoperative MR guidance.

BACKGROUND AND PURPOSE: Length of survival of patients with low-grade glioma correlates with the extent of tumor resection. These tumors, however, are difficult to distinguish intraoperatively from normal brain tissue, often leading to incomplete resection. Our goal was to evaluate the effectiveness of intraoperative MR guidance in achieving gross-total resection. METHODS: We studied 12 patients with low-grade glioma who underwent surgery within a vertically open 0.5-T MR system. During surgery, localization of residual tumor tissue was guided by interactive, near real-time imaging. The amount of residual tumor tissue on MR images was evaluated at the point of the operation at which the neurosurgeon would have terminated the procedure under conventional conditions (first control) and again before closing the craniotomy. RESULTS: Significant residual tumor (more than 10% of original tumor volume) was shown in eight patients at the first control condition. The percentage of resection varied from 26% to 100% (mean, 68%) at this time. Twelve tissue samples from seven patients were obtained in areas identified as residual tumor on MR images. In 10 cases, the neuropathologic investigation confirmed the presence of residual low-grade glioma; in two cases, the borderzone of tumor was identified. In evaluating the final sets of images, we found total resection in six cases, over 90% resection in five cases, and 85% resection in one case (mean, 96%). CONCLUSION: Surgical treatment of low-grade gliomas under intraoperative MR guidance provides improved resection results with maximal patient safety.

Adult↗

PubMed2000

Protein S-100B as a serum marker of brain damage in severe head injury: preliminary results.

The objective of our study was to investigate S-100B protein as a serum marker of brain cell damage after severe head injury. Eighty-three patients with severe head injury (Glasgow Coma Scale < or =8) were included in this prospective study. Venous blood samples for S-100B protein were taken after admission and every 24 h for a maximum of 10 consecutive days. Outcome was assessed at 6 months using the Glasgow Outcome Scale. In this study, we analysed the preliminary results from the outcomes of 25 patients at 6 months. Levels of S-100B were significantly higher in patients with unfavourable outcome compared to those with favourable outcome. In patients with favourable outcome, slightly increased initial levels of S-100B returned to normal within 3 to 4 days. In patients with unfavourable outcome, initial levels were markedly increased, with a tendency to decrease from day 1 to day 6. After day 6, there was a secondary increase in serum S-100B, indicating secondary brain cell damage. Our preliminary results suggest that serum S-100B protein might be a promising biochemical marker which may provide additional information on the extent of primary injury to the brain and the prediction of outcome after severe head injury.

Adolescent↗

PubMed2000

Open MRI-guided microsurgery of intracranial tumours. Preliminary experience using a vertical open MRI-scanner.

OBJECTIVES: A number of different image-guided surgical techniques have been developed during the past decade. None of these methods can provide the surgeon with information about the dynamic changes that occur intra-operatively. The development of open configurated MRI-scanners leads to new perspectives in the intra-operative management and resection control of intracranial tumours. MATERIAL AND METHOD: Using a vertical open 0.5 T MRI-scanner for intra-operative MR image guided neurosurgery, forty-four patients (20 female/24 male) with different intracranial tumours have been operated on since August 1997. The patients ranged in age from 20 to 70 years (mean +/- standard deviation = 47.2 +/- 15.9 ys). RESULTS: In 36 (82%) of 44 patients the tumours were completely removed with the aid of MR image-guidance. In 8 cases (18%) complete removal was not achieved. Postoperatively 6 (14%) of 44 patients developed neurological deficits which were transient in 5 cases (paresis, dysphasia). In these patients the tumours were located in or near eloquent brain areas (sensorimotor cortex/speech center). CONCLUSION: Intra-operative MRI is helpful for navigation as well as determining of tumour margins to achieve a complete and safe resection of intracranial lesions. Complications related to the surgical procedure are reduced and the risk of neurological deterioration due to tumour removal and postoperative complications is minimized. It can be concluded that the intra-operative application of interventional MRI technology may represent a major step foreward in the field of neurosurgery.

Adult↗

PubMed2000

Informed consent in neurosurgery: patients' recall of preoperative discussion.

OBJECTIVE: Informed consent (IC) is an important principle of modern medicine and the quality of the process is likely to receive increasing attention in future due to complex surgical procedures and a development of social mistrust for medical treatment. Medico-legal action is also becoming an important influence on IC, in particular the extent of warning to be given about the degree of risk. Evaluation of IC, however, encounters various problems. One key element of a knowledgeable decision is an analysis based on the disclosed risks. METHODS: In a prospective study, 104 consecutive patients were asked to write down as many items of the list of risks as possible two hours after consent interview. The sample included adults (mean age: 52 years) without any significant neuropsychological impairment who underwent elective intracranial (52%) or spinal (48%) surgery. Consent interview based on the proposals of the Deutsche Gesellschaft für Neurochirurgie and the Berufsverband Deutscher Neurochirurgen 1998. The average number of disclosed risks was 32 in intracranial and 25 in spinal surgery. According to the results in the literature 6 'typical major risks' of the proposed treatment were selected. RESULTS: The median value of the total of recalled risks was 4 in the spinal group and 5 in the intracranial group. The mean score of general information retention was 18%. 65% of the patients did not recall more than 2 of 6 'typical major risks'. No significant correlation between recall performance and age or education was found. CONCLUSION: The general principles of memory apply and have implications in states of emotional arousal. Whereas education and age, unlike in previous reports, did not appear to influence recall, thus indicating that we had succeeded in tailoring IC to the individual, recall rate was low in most cases. Physicians should highlight the discrepancy and conflict between the requirements for the defence of medical practice in the law courts and the actual interests of patients. They should promote research to establish what really is 'appropriately informed consent'.

Adult↗

PubMed2000

[Institutionalization of skull base surgery. Development, concept and initial experiences of the interdisciplinary center for skull base surgery of the Leipzig University].

The treatment of complex tumorous, inflammatory, traumatic, vascular processes, or developmental disorders of the skull base increasingly needs the interdisciplinary cooperation of specialties involved in diagnostics or treatment. Due to this inevitable cooperation of different hospital specialties, institutionalization of skull base surgery, organized as a center or working group, seems recommendable. Moreover, such a center may have additional effects on the external representation of skull base surgery, which is also important. On the initiative of 11 departments and institutes of the university hospital of Leipzing, the Interdisciplinary Center of Skull Base Surgery (IZSL) was founded in March 1997. The following aims were proclaimed: improvement of the interdisciplinary clinical treatment of patients with skull base diseases, evaluation of the patient's data, advancement of clinical and experimental research on the field of skull base surgery, as well as the organization of meetings for training and teaching and scientific meetings. Structure, concept, and first experiences of the interdisciplinary center of skull base surgery are discussed.

Germany↗

PubMed2000

Factor XIII deficiency and postoperative hemorrhage after neurosurgical procedures.

BACKGROUND: Factor XIII is of physiological importance for hemostasis, especially in patients undergoing surgery. It catalyzes the enzymatic cross-linking of fibrin monomers into stable polymers and protects polymers from plasmatic and nonspecific degradation. Postoperative hemorrhage in patients with congenital and acquired Factor XIII deficiencies has been described in various surgical fields. However, there are no data about the incidence and clinical relevance of decreased Factor XIII after neurosurgical procedures. The objective of our study was to investigate the association between Factor XIII deficiency and postoperative hemorrhage after intracranial surgery. METHODS: A total of 1264 patients who underwent intracranial operations were reviewed retrospectively. Standard coagulation parameters were monitored during the perioperative course in all patients. Factor XIII testing was performed postoperatively in 34 patients in whom coagulopathies were suspected despite normal platelets, fibrinogen, prothrombin, and partial thromboplastin time. Data were analyzed to evaluate the association of Factor XIII deficiency and major postoperative hemorrhage. RESULTS: In this series of 1264 patients, a total of 20 patients (1. 6%) suffered from a major postoperative hemorrhage. Of the 34 patients with suspected coagulopathies and postoperative Factor XIII testing, 11 had a major postoperative hemorrhage. Normal levels of Factor XIII, defined as more than 60%, were found in 26 of the 34 patients. Factor XIII deficiency, defined as less than 60%, was found in eight patients. All patients with Factor XIII deficiency (n = 8) had a major postoperative hemorrhage. Of the remaining 26 patients with normal Factor XIII levels only three had a postoperative hemorrhage (p < 0.00001, Fisher's exact test). CONCLUSIONS: Decreased Factor XIII activity may be associated with an increased risk of postoperative hemorrhage after intracranial surgery.

Adult↗

PubMed2000

[Practice of perioperative thromboembolic prophylaxis in neurosurgery: results of a German survey].

Many neurosurgical patients are at high risk of developing thromboembolic disease. Although recent data support the benefit of pharmacological thromboembolic prophylaxis, the optimal starting point for the different neurosurgical procedures remains unclear because the potentially devastating consequences of intracranial or intraspinal haemorrhage could easily offset the reduction in thromboembolic morbidity and mortality resulting from pharmacological thromboembolic prophylaxis. The objective of our study was to assess the use of pharmacological methods of thromboembolic prophylaxis in contemporary German neurosurgery using a postal survey in 34 neurosurgical departments. Low-dose heparin or low molecular weight heparin (LMWH) were used in 88% to 97% of neurosurgical units participating in our survey. In craniotomies, in 2 units (6%) heparin or LMWH was routinely started before surgery, in 10 units (29%) < 8 hours after surgery, in 15 units (44%) < 24 hours after surgery, in one unit at the second day and in 5 units at the third day after surgery. Data for burr hole craniotomy or spinal surgery were similar. In our survey a high rate of perioperative use of pharmacological thromboembolic prophylaxis was found. However, given the data from the literature, the optimum protocol remains unclear.

Anticoagulants↗

PubMed2000

Dynamic examination of the lumbar spine by using vertical, open magnetic resonance imaging.

OBJECT: The aim of this study was to determine the relationship of different structures of the lower lumbar spine during interventional movement examination. METHODS: Clinically healthy volunteers and patients suffering from degenerative disorders of the lumbar spine underwent vertical, open magnetic resonance (MR) imaging (0.5 tesla). Three functional patterns of lumbar spine motion were identified in 50 healthy volunteers (average age 25 years). The authors identified characteristic angles of the facet joints, as measured in the frontal plane. In 50 patients with degenerative disorders of the lumbar spine (41 with disc herniation, five with osteogenic spinal stenosis, and four with degenerative spondylolisthesis) the range of rotation was increased in the relevant spinal segments. Signs of neural compression were increased under motion. CONCLUSIONS: Dynamic examination in which vertical, open MR imaging is used demonstrated that the extent of neural compression as well as the increasing range of rotation are important signs of segmental instability.

Adult↗

PubMed1999

Spinal markers: A new method for increasing accuracy in spinal navigation.

Spinal navigation opens up a completely new dimension in the planning and realization of neurosurgical and orthopedic procedures, and offers the possibility of simulating the operation preoperatively. There is currently only limited experience with spinal navigation, and despite the development of advanced software, intraoperative difficulties include identification of characteristic and reproducible anatomical landmarks, localization of these points in the surgical field, referencing, and intraoperative control. We report the use of a new kind of implantable fiducial marker in a case of a 58-year-old female patient with spondylolisthesis. Percutaneously applied spinal markers were used as prominent anatomical landmarks and permitted much easier intraoperative handling. In our opinion, in the hands of an experienced neurosurgeon or orthopedist, the additional preoperative time required for placement of such spinal markers is negligible.

Bone Nails↗