Search PubMed⌕ Search

Biomedical subjects

V Seifert

Publications and source records attributed to V Seifert.

At least 127 records · Page 7Linked to original sources
PubMed1989

[Clinical use of a new method in microsurgical transplantation of peripheral nerves].

Due to its biophysical properties the CO2-laser has been mainly used for atraumatic incision of neural tissue or for ablative procedures like vaporisation of poorly vascularized tumors of the CNS. The possibility to use the thermal effect of laser energy to bond organic tissue, especially when a low energy CO2 laser working in the milliwatt range is employed, has emerged from recent experimental studies. The concept of laser assisted reconstructive procedures like anastomosis of vessels and nerves has been summarized under the concept of tissue welding. After extensive experimental studies incorporating peripheral and cranial nerves the technique of laser nerve welding has been used in a patient with a traumatically sectioned median nerve. A sural nerve graft consisting of 5 fasciles was used for interposition. Each fascicle was microsurgically welded to the distal and proximal median nerve stump using low power energy of 75 to 100 milliwatt in the continuous application mode. The postoperative course was uneventful. Electrophysiological as well as clinical examination at follow up 6 months post surgery revealed already satisfactory nerve regeneration with nerve conduction velocities measurable across the anastomotic side and positive Hoffmann-Tinel sign. It is suggested that laser assisted nerve anastomosis using the CO2 milliwattlaser might be a promising technique for microsurgical reconstruction of sectioned nerves.

Adult↗
PubMed1989

Efficacy of single intracisternal bolus injection of recombinant tissue plasminogen activator to prevent delayed cerebral vasospasm after experimental subarachnoid hemorrhage.

Premature lysis of subarachnoid blood clots by thrombolytic substances such as urokinase and plasmin has been shown to be efficacious in preventing cerebral vasospasm in clinical and experimental investigations. Recently, tissue plasminogen activator (rtPA) derived from recombinant deoxyribonucleic (DNA) technology has been introduced as a new thrombolytic substance. With its high affinity for fibrin-bound plasminogen and low affinity for circulating plasminogen by which a clot-selective fibrinolysis can be achieved without the danger of inducing systemic fibrinogenolysis, rtPA might be the ideal substance for the postoperative lysis of cisternal blood accumulations after subarachnoid hemorrhage. The efficacy of rtPA in preventing delayed cerebral vasospasm after experimental subarachnoid hemorrhage using a single intracisternal bolus injection of this agent was investigated. With a single injection of 25 micrograms of rtPA into the cisterna magna 48 hours after the first and 6 hours after the second injection of blood in the two-hemorrhage model of cerebral vasospasm, angiographic spasm of the basilar artery was completely prevented in all animals so treated whereas in the control group severe vasospasm occurred. Autopsy studies of the experimental animals demonstrated that the subarachnoid blood clots were almost completely removed by intracisternal rtPA application. Additionally the pathomorphological signs of proliferative vasculopathy present in all animals of the control group were not demonstrable in the rtPA group. As intracisternal bolus injection of rtPA is highly efficacious in preventing angiographic as well as pathomorphological vasospasm, it is concluded that use of this thrombolytic substance might be a promising approach for pharmacological blood clot removal.

Animals↗
PubMed1989

Laser-assisted microsurgical extirpation of a brain stem cavernoma: case report.

A 43-year-old woman presented with progressing signs of a space-occupying brain stem lesion. A computed tomographic scan revealed a hyperdense process located in the pons. Magnetic resonance imaging confirmed the lesion, which had a reticulated core of increased and decreased signal intensity. Vertebral angiography did not show any vascular supply of the process. The patient was operated upon in the lateral park bench position. The lesion, being located close to the exit zone of the trigeminal nerve, could be removed totally with incision of the brain stem and atraumatic vaporization of the tumor tissue with the CO2 laser. Despite the fact that the histopathological examination revealed a cavernous angioma the application of laser energy was judged to be extremely valuable for the surgical procedure. It was concluded that with proper selection of application mode and wattage the CO2 laser may be used for extirpation of vascularized lesions also especially when situated in or close to deep lying vital structures of the brain.

Adult↗
PubMed1989

Intra- and postoperative complications in lumbar disc surgery.

In a prospective study, 412 primary and 69 reoperations for herniated lumbar disc were observed and intra- and postoperative complications compiled. Only surgeons with the experience of more than 100 surgical procedures on lumbar discs entered this study. The complication rates of the micro- and macrosurgical techniques are compared. Intraoperative complications range from 7.8% in the microdiskectomies and 13.7% in the macrodiskectomies to 27.5% in the reoperations. Postoperative complications range from 1.4% in reoperation, 3.9% in the microdiskectomies up to 4.2% in the macrodiskectomies. The risk of complications correlates with the age of the patient and the operating time.

Adult↗
PubMed1989

Cavernous angiomas of the supratentorial compartment.

In a retrospective study the clinical data of ten consecutive patients with a cavernous angioma (cavernoma) confined to the supratentorial compartment are presented. The lesions were almost equally distributed among the cerebral cortex with three cavernomas each in the parietal and temporal region and two lesions each being located in the frontal and occipital lobes. The predominant clinical symptoms were either focal or generalized seizures which occurred in 8 patients. One patient became symptomatic due to an intracerebral bleeding from the cavernous angioma, one patient developed a visual field defect from an occipitally localized cavernoma. In 7 patients the neurological status on admission was normal, two patients had signs of a slowly progressing psychosyndroma, one patient had a homonymous hemianopia. The time interval from onset of symptoms to final diagnosis showed a considerable variability ranging from one months to 33 years. Only in half of the patients this interval was less than 6 months. CT-scan was the most important radiological procedure for the diagnosis of these malformations, while MRI may be even more sensible in detecting these lesions in the future. The treatment of choice for these tumorous vascular malformations is microneurosurgical extirpation. This can be accomplished with neglectible morbidity leading to a significant decrease of the preoperative incidence and severity of epileptic seizures.

Adolescent↗
PubMed1989

[The postoperative treatment of hypertension with urapidil in patients with cerebrovascular aneurysms].

In 10 patients with subarachnoidal haemorrhage and an identified aneurysm the blood pressure was reduced intraoperatively by means of sodium nitroprusside. Arterial and intracranial pressures were continuously recorded in all patients. In 9 patients a rebound phenomenon occurred as manifested by an increase in blood pressure during the postoperative phase after sodium nitroprusside infusion. Rapid reduction of blood pressure was achieved in all patients by a bolus injection of initially 25 mg Urapidil. Undesirably low blood pressure values were seen in a patient. The continuously recorded intracranial pressure remained in the normal range in all patients. Blood pressure reduction by means of Urapidil does not exercise any influence on intracranial pressure, in contrast to blood pressure reduction via nitroglycerin, sodium nitroprusside, dihydroalacin and diazoxide.

Adult↗
PubMed1989

Laser-assisted reconstruction of the oculomotor nerve: experimental study on the feasibility of cranial nerve repair.

In this experimental study the feasibility of microsurgical laser-assisted repair of the oculomotor nerve in the cat was investigated. The 3rd cranial nerve was explored after a temporobasal craniectomy from its exit at the brain stem to its entrance into the cavernous sinus and transected. The cut nerve ends were loosely reapproximated and welded together with a CO2 milliwatt laser using a power setting of 80 to 90 mW and a spot size of 150 mu. Regeneration of the oculomotor nerve within an observation period of 12 months as assessed by weekly examination of the pupil diameter was excellent in 4 animals and satisfactory in 2. In the two control groups consisting of 6 animals in which the nerve reconstruction had been performed with fibrin glue or by simple nerve reapproximation minimal nerve regeneration could be observed only in one animal. The histomorphological examinations revealed good regeneration across the laser anastomosis including new formation of a perineural sheath without any significant scarring effect or constriction at the anastomotic site. It is concluded that the CO2 milliwatt laser might be a useful tool for the microsurgical repair of cranial nerves and should possibly be incorporated into the neurosurgical armamentarium of reconstructive cranial nerve surgery.

Animals↗
PubMed1988

Timing of aneurysm surgery. Comparison of results of early and delayed surgical intervention.

In a retrospective study covering a period of 8 years and 403 surgically treated patients the results of microsurgical aneurysm treatment were compared between two groups. One group received surgical treatment within 72 h and the second were treated surgically after this time interval. The data indicated that patients receiving delayed surgery had a better outcome at 6 months as compared to patients receiving immediate surgical intervention. The location of the aneurysm and the preoperative neurological status imparted the most significant impact on the subsequent outcome and on the incidence of rebleeding. High risk patients with poor neurological status on admission seemed to have a considerable chance of gaining satisfactory functional recovery, especially with a more delayed surgical approach. Despite its superior results delayed surgery was burdened with a rebleeding rate and an incidence of ischemic deficits due to cerebral vasospasm twice as high as in patients receiving early surgery. The implications of these results on surgical timing are discussed and it is concluded that despite the fact that late surgery yields better results than early surgery, the considerable reduction of recurrent hemorrhage and additional possibility of aggressive treatment of incipient vasospasm makes early surgery a promising alternative for the treatment of patients with aneurysmal subarachnoid hemorrhage.

Carotid Artery Diseases↗
PubMed1988

Intraspinal lipomas in infancy and childhood causing a tethered cord syndrome.

The authors report on a series of 26 children with spina bifida occulta in combination with intraspinal lipoma and clinical signs of tethered cord syndrome. The age of the children at presentation ranged from 1 month to 12 years. The typical signs and symptoms consisted of skin lesions in the lumbar-sacral region, neurogenic foot deformities, and bladder and bowel disturbances. The diagnosis was confirmed by neuroradiological investigations including lumbar myelography, computerized tomography, and only recently magnetic resonance imaging. Indications for surgery were based on the radiological evidence of intraspinal lipoma and tethered cord and especially on the clinical signs of neurological deterioration. The results of the operative treatment are presented and the role of surgery before onset of symptoms as well as during the symptom-free interval is discussed.

Child↗
PubMed1988

[Intraspinal lipoma with tethered cord syndrome in childhood].

In this article the authors report on a series of 26 children with spina bifida occulta in combination with intraspinal lipoma and clinical signs of tethered cord syndrome. The age of the children at presentation ranged from 1 month to 12 years. The typical signs and symptoms of the patients consisted of dermatological changes in the lumbosacral region, neurogenic foot deformities and genitourinary tract anomalies with disturbed bladder function. The diagnosis was confirmed by neuroradiological studies including lumbal myelography, spinal computerized tomography and only recently magnetic resonance imaging. Indications for surgery were based on the radiological evidence of intraspinal lipoma and tethered cord and especially on the clinical signs of neurological deterioration. The results of the operative treatment are presented and the role of surgery before onset of symptoms as well as during the symptom-free interval are discussed.

Child↗
PubMed1988

[Postoperative lumbar intervertebral discitis. A review of a 15-year period and 7,493 operations].

The incidence of postoperative discitis in a series of almost 7500 surgical interventions covering a period of 15 years is reported. Ninety patients (1.2%) were found to be suffering from typical symptoms, which are described and discussed. It is pointed out that above all radicular pain diminished, while on the other hand severe pain occurred in the lumbar spine, caused by movement and vibration, accompanied by a usually sharp rise in ESR, up to values of 100/200 mm. It is pointed out that conventional tomography is the diagnostic tool of choice, diagnosis being possible as of approx. three weeks postoperatively. The social implications of this important complication are pointed out, in particular the fact that only 50% of patients were able to return to full-time work in their old occupations, while the rest had to retire or accept a less strenuous job.

Adult↗
PubMed1988

[Early or late operation on the ruptured aneurysm? An analysis based on 356 cases].

From January 1979 to December 1985 356 patients underwent microsurgery for a ruptured intracranial aneurysm. 150 patients (42%) were operated on early, i.e. within 72 hours after subarachnoidal haemorrhage. 206 (58%) were operated on after this period. Both groups of patients were compared with one another in respect of preoperative staging (Hunt and Hess), localisation of the aneurysm, postoperative recovery (Glasgow-Outcome-Scale) and frequency of recurrent haemorrhages. 48% of the patients who were operated on early were preoperatively in stages I and II, 32% in stage III and 20% in stages IV and V. In the group of patients who were operated on late, 64.6% were in stages I and II, 17.5% in stage III and 17.9% in stages IV and V. 72.5% of the patients receiving early surgery in stages I to II showed a positive postoperative result (grades I and II of the Glasgow-Outcome-Scale = GOS) compared against 80.5% of those undergoing late surgery. 9.2% or 3.5% survived with considerable neurological deficits (GOS III). 18.3% or 15.4%, respectively, remained in the vegetative stage or died (GOS IV and V). A satisfactory postoperative result was obtained even in patients subjected to surgery in stages IV and V, in the following proportions: 40% if operated on early, and 48.6% if operated on late (GOS I and II). Aneurysms of the anterior communicating artery were most frequent, followed by aneurysms of the internal carotid artery and the middle cerebral artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Damage, Chronic↗
PubMed1988

Influence of blood volume on cerebrospinal fluid levels of arachidonic acid metabolites after subarachnoid hemorrhage: experimental study on the pathogenesis of cerebral vasospasm.

Based on accumulating data indicating the important role of arachidonic acid metabolites in the pathogenesis of cerebral vasospasm, we examined the influence of alterations in blood volume on the cerebrospinal fluid (CSF) level of the subarachnoid hemorrhage (SAH). Three separate injections of autologous blood into the cisterna magna of dogs within subarachnoid hemorrhage (SAH). Three separate injections of autologous blood into the cisterna magna of dogs within 72 hours were performed. Three experimental groups were formed, with an overall injected blood volume of 6, 9, and 12 ml. Arterial spasm was verified by comparison of the angiographic diameter of the basilar artery on Day 8 vs. Day 1. Additionally, light microscopic, scanning and transmission electron microscopic, and freeze cracking technique examinations of the basilar artery demonstrated the typical morphological features of proliferative vasculopathy. Increasing the volume of experimental SAH led to a linear decrease of the mean vessel diameter from 45% to 53% and finally to 75% of normal. Parallel to the reduction of angiographic vessel lumen, a volume-dependent significant increase of all three eicosanoids was demonstrated. A deficiency of prostacyclin concentration during the course of the experiment was not observed. Despite highly elevated CSF levels of vasodilating prostacyclin, however, severe angiographic constriction of the basilar artery occurred in the presence of high concentrations of TXA2 and PGE2. It is concluded that increasing volumes of SAH led to a concomitant release of arachidonic acid metabolites during posthemorrhagic clot lysis. From our data, it seems questionable whether a prostacyclin deficiency is an important underlying factor for the development of cerebral spasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Arachidonic acid metabolism following aneurysm rupture. Evaluation of cerebrospinal fluid and serum concentration of 6-keto-prostaglandin F1 alpha and thromboxane B2 in patients with subarachnoid hemorrhage.

Experimental investigations have suggested an important role of arachidonic acid metabolites in the genesis of cerebral vasospasm following subarachnoid hemorrhage. In this clinical study the cerebrospinal fluid (CSF) and serum levels of the two main arachidonic acid metabolites prostacyclin and thromboxane A2 are evaluated by measuring their stable degradation products 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TXB2) using radioimmunoassay methods during the pre- and postoperative course in patients after aneurysm rupture. Although the serum levels of both substances do not seem to be important for the clinical course of the patients, the CSF concentrations of 6-keto-PGF1 alpha and TXB2 provide important data. A close correlation between the initial TXB2 level of the individual patient and the amount of blood in the basal cisterns as detected by computed tomography scan can be demonstrated. The predictive value of this additional information for the occurrence of cerebral angiospasm is discussed. Comparing the CSF levels of both metabolites the slight preoperative elevation of 6-keto-PGF1 alpha is significantly surmounted by an extraordinary rise in TXB2 concentration. Postoperatively, after cleavage of the basal cisterns there is a decline in the CSF levels of both substances. The pre- and postoperative clinical course in comparison to the CSF levels of 6-keto-PGF1 alpha and TXB2 is demonstrated in four patients. A nearly normal course of TXB2 and 6-keto-PGF1 alpha seems to be associated with an uneventful clinical course, whereas a high TXB2 level--whether occurring preoperatively or, even more important, as a secondary postoperative rise--seems to be associated with ischemic complications and neurological deterioration. It is suggested that pre- and postoperative monitoring of CSF levels of 6-keto-PGF1 alpha and especially TXB2 may serve as a possible indicator for the detection of patients at risk of developing cerebral vasospasm.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

[Arachidonic acid metabolism following aneurysm rupture].

Imbalance between the two arachidonic acid metabolites, prostacyclin (PGI2) and thromboxane A2 (TXA2), is thought to be at least in part responsible for the development of cerebral vasospasm following aneurysm rupture. In 12 patients with subarachnoid hemorrhage the pre- and postoperative serum and CSF levels of PGI2 and TXA2 were measured as a function of their stable hydrolysis products, 6-Keto-PGF1 alpha (PGI2) and thromboxane B2 (TXA2), with a highly specific radioimmunoassay. Serum levels of both metabolites were elevated in half of the patients, but no correlation to the clinical course could be found. However, TXB2 concentration in the CSF was significantly increased preoperatively with close correlation to the amount of intracisternal blood, as detected by CT scan. Furthermore, it could be demonstrated that the postoperative course of the TXB2 concentrations in the CSF reflects the clinical course in such a way that a characteristic secondary rise of TXB2, concentration postoperatively is closely related to the occurrence of cerebral vasospasm and clinical deterioration. The conclusion is drawn that measurement of arachidonic acid metabolites in the CSF may provide important information concerning the pathophysiological events following subarachnoid hemorrhage, especially with regard to incipient cerebral vasospasm.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

[Modification of intracranial pressure by urapidil following experimental cold lesions in the cat].

The action of the antihypertensive agent Urapidil was investigated in an experimental animal model of vasogenic brain oedema. Animals with normal or raised intracranial pressure received Urapidil as a bolus injection (0.25 mg/kg body weight) followed by a continuous infusion of Urapidil (1 mg/kg body weight). The bolus injection of the drug was followed by a sharp fall in systemic blood pressure, paralleled by a rise in intracranial pressure, resulting in a shortlasting decline of cerebral perfusion pressure. During continuous infusion of Urapidil in both groups with normal or elevated ICP there was a long-lasting significant fall in the systemic blood pressure without any significant alteration of the intracranial pressure.

Animals↗