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Biomedical subjects

D Stolke

Publications and source records attributed to D Stolke.

At least 19 recordsLinked to original sources
PubMed1992

Single intracisternal bolus of recombinant tissue plasminogen activator in patients with aneurysmal subarachnoid hemorrhage: preliminary assessment of efficacy and safety in an open clinical study.

Intracisternal thrombolysis with recombinant tissue plasminogen activator (rtPA) was performed in 20 patients with aneurysmal subarachnoid hemorrhage. All patients had blood accumulations in the basal cisterns according to Fisher's Grade III, thus being at a high risk for the development of posthemorrhagic delayed ischemic deficits (DID). All patients underwent an operation within 72 hours after aneurysm rupture. After the aneurysm had been excluded from the cerebral circulation, a single bolus of 10 mg of rtPA was injected into the basal cisterns. Postoperatively, serial computed tomographic examinations demonstrated radical blood clot removal in all patients. Daily transcranial Doppler examinations revealed accelerated blood flow velocities in 16 of 20 patients. The postoperative results according to the Glasgow Outcome Scale were as follows: 16 patients were Grades I and II, 2 patients were Grade III. Two patients died postoperatively, 1 because of a bowel perforation, and 1 from DID attributable to the development of a cerebral vasospasm. No postoperative bleeding complications occurred. It is concluded that pharmacological removal of subarachnoid blood accumulations can be achieved in a safe and effective way by an intrathecal single bolus of 10 mg of rtPA instilled into the basal cisterns after aneurysm clipping. The acceleration of blood flow velocities in a number of patients indicated that posthemorrhagic arterial narrowing was not completely prevented by this treatment, but this remained asymptomatic in 19 of 20 patients. Although extensive blood clot removal can be achieved by a single bolus of rtPA, more radical or complete blood removal probably requires the use of higher drug concentrations or additional postoperative intracisternal or intraventricular rtPA injections, for which further studies are needed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Cervical intramedullary cavernous angioma with MRI-proven haemorrhages.

Two contrasting cases of cervical intramedullary cavernous angioma in young female patients are reported. One patient had a 3-year course of step-wise progressive tetraparesis; at each of the five events intramedullary bleeding from a cryptic vascular malformation at C6-7 level was diagnosed by MRI. The other patient presented with one episode which led to MRI diagnosis of a vascular malformation at the C2 level. Both patients eventually underwent complete surgical excision of the angioma with subsequent steady improvement of the neurological deficit.

Adult↗
PubMed1991

Cranio-cervical stabilization using contoured luque rectangles.

Cranio-cervical stabilization using preformed Luque rectangles supplemented by autologous bone grafts was performed in 18 patients. Stability at the cranio-cervical junction had been impaired by a number of diseases including rheumatoid arthritis in 12 patients. Metastatic tumour in 5 patients and post-operative swan neck deformity in one patient. In all patients immediate stabilization as well as long-term bony fusion could be achieved, paralleled by improvement of the preoperative neurological condition in differing degrees. Surgery related complications were rare, although, considering the patient population treated, medical and anaesthesiological complications as a result of accompanying diseases may pose serious problems. The technical details of the surgical procedure are described and its application for the treatment of cranio-cervical instability is discussed.

Adult↗
PubMed1991

Effect of intrathecal fibrinolysis on cerebrospinal fluid absorption after experimental subarachnoid hemorrhage.

The effect of intrathecal fibrinolysis on cerebrospinal fluid (CSF) absorption was investigated after experimental subarachnoid hemorrhage (SAH). In 11 cats, SAH was induced by intracisternal application of 1 to 4 ml of fresh autologous blood. Thirty minutes after the experimental SAH, the CSF outflow resistance was found to be elevated from a median of 77 mm Hg/ml/min (range 41.3 to 109 mm Hg/ml/min) to a median of 580 mm Hg/ml/min (range 104 to 7000 mm Hg/ml/min). A logarithmic relationship could be demonstrated between the volume of subarachnoid blood and the elevation of the CSF outflow resistance. The intrathecal application of 2 mg of recombinant tissue plasminogen activator (rt-PA), which is a fibrinolytic substance suitable for lysis of subarachnoid blood clots in man, resulted in an almost total restoration of CSF absorption after experimental SAH. The CSF outflow resistance after SAH was lowered by application of rt-PA from a median of 1028.05 mm Hg/ml/min (range 394 to 7000 mm Hg/ml/min) to 79 mm Hg/ml/min (range 56.7 to 223 mm Hg/ml/min). It is concluded that the impairment of CSF absorption after SAH may play an important role in the pathogenesis of post-hemorrhagic vasospasm.

Animals↗
PubMed1991

Multisegmental cervical spondylosis: treatment by spondylectomy, microsurgical decompression, and osteosynthesis.

Vertebral body replacement after spondylectomy, combined with microsurgical decompression and anterior plating, was performed in 22 patients as an aggressive therapeutic approach to multisegmental cervical spondylosis. The patients were 13 men and 9 women, ranging in age from 32 to 74 years. In 19 patients, the typical signs of cervical myelopathy were present. In three patients, pain was the major symptom, accompanied by moderate spastic paresis and hyperreflexia. Apart from cervical myelography and computed tomographic scanning, which was performed in 10 patients, magnetic resonance imaging was the radiological procedure of choice in 12 patients. During spondylectomy, one vertebra was removed in 14 patients, two vertebrae in seven patients, and three vertebrae in one patient. The time of postoperative follow-up ranged from 8 to 46 months, with an average interval of 21 months. In all 22 patients, satisfactory bony fusion was achieved as demonstrated by radiological control examinations. Seventeen patients (77%) were symptom free or had only minor residual symptoms. Three (14%) patients had intermittent nuchal or cervicobrachial pain, which responded well to analgesic medication or the application of a soft collar. Two (9%) patients still had myelopathic but not incapacitating symptoms. Of 15 patients who were employed before surgery, 13 returned to a full-time job. The only severe complication of surgery was a prevertebral abscess that healed without sequelae. It is concluded that aggressive surgical therapy of multisegmental cervical spondylosis by a combination of vertebrectomy, decompression (using the surgical microscope), bone grafting, and osteosynthesis is a straightforward and promising procedure for the treatment of this debilitating disease.

Adult↗
PubMed1990

Management morbidity and mortality in grade IV and V patients with aneurysmal subarachnoid haemorrhage.

In a retrospective study the clinical management of 74 patients with aneurysmal subarachnoid haemorrhage (SAH) admitted in grade IV and V Hunt and Hess was examined. 39 patients (53%) were admitted within 24 hours after SAH, 29 patients (39%) between 24 and 72 hours after SAH, and 6 patients 8%) later than this time interval. The ruptured aneurysms were located at the anterior communicating artery complex in 34 patients (46%), on the middle cerebral artery in 19 patients (26%), on the internal carotid artery in 12 patients (16%) and at the vertebro-basilar artery complex in 9 patients (12%). In 38 patients (51%) no surgical attack on the aneurysm was performed. 19 (50%) of these patients were in grade IV on admission and 19 (50%) in grade V. In 36 patients (49%) the aneurysm was clipped. Of these patients 29 (81%) were in grade IV and 7 (19%) in grade V. Of the 38 patients in whom no aneurysm surgery was done, 37 patients died, representing a mortality rate of 97%, one patient survived in grade III Glasgow Outcome Scale (GOS). Concerning the outcome in those patients with aneurysm clipping, of 19 patients in grade IV operated on early, 10 patients (53%) made a good recovery, 3 (16%) were left severely disabled and 6 patients (31%) remained in a vegetative state or died. Of the 10 patients in grade IV with delayed surgery 4 (40%) were in grade I and II postoperatively, 2 (20%) in grade III, and again 4 (40%) in grade IV and V GOS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Cerebral perfusion pressure in acute blood pressure decrease with hyperosmolar sorbitol in anesthesia conditions].

Osmotherapy with sorbitol during intracranial surgery caused a significant decrease in arterial blood pressure. It was shown that this sometimes very desirable reaction did not cause relevant decreases in cerebral perfusion pressure, but was on the contrary accompanied by an increase in cerebral perfusion pressure in patients with severely elevated ICP (greater than 30 mmHg). 8 patients were studied by measuring the arterial and intracranial pressure during intraoperative infusions of sorbitol 40% (3 ml/kg body weight). Our findings are explained by the simultaneous decrease in arterial and intracranial pressure. During intracranial surgery sorbitol can be used as the antihypertensive agent of choice for treating hypertensive dysregulation of arterial blood pressure in the initial phase of craniotomy before opening the dura.

Anesthesia, General↗
PubMed1990

[Microsurgery of spinal angioblastoma].

The treatment results of ten patients with spinal hemangioblastoma including clinical, radiological and surgical considerations are reported. Magnetic resonance imaging (MRI) is considered to be the radiological method of choice. With its superior imaging qualities MRI was able to clearly demonstrate the exact anatomical location of the tumor nidus as well as the extent and location of the accompanying space-occupying intramedullary cysts. The tumors could be completely removed in all ten patients using microsurgical techniques. The additional application of the CO2-laser has added significantly to the atraumatic and total tumor extirpation. In none of the patients postoperative worsening occurred. In two patients with long lasting symptoms the pre- and postoperative neurological status was unchanged. Minor sensory sequelae persisted in another two patients. In 6 patients the preoperative neurological deficits including significant motor and sensory disturbances resolved completely. It is concluded that microsurgical removal guided by MRI imaging and aided by the application of laser energy is the method of choice in the treatment of spinal hemangioblastomas.

Adolescent↗
PubMed1990

[Trans-sphenoid microsurgery of craniopharyngioma].

This paper presents the microsurgical transsphenoidal approach to intracranial craniopharygiomas. Essential prerequisites for this route are stressed: enlarged sella, growth into the sphenoid sinus, intact diaphragma sellae. The authors' own material is discussed. It is pointed out that even repeated transsphenoidal decompression of large cystic lesions is well tolerated in elderly patients.

Adult↗
PubMed1990

[Cerebrospinal fluid penetration of ofloxacin (Tarivid) in non-inflamed meninges].

In 9 patients, who underwent lumbar drainage after transsphenoidal surgery for pituitary adenoma, we collected 69 samples of CSF and plasma, respectively. The concentration of ofloxacin was measured bacteriologically. Considering the ofloxacin CSF and plasma levels related to time some aspects of pharmacokinetics are discussed. With maximum CSF concentrations coming up to 40% of plasma levels liquor penetrability is quite good. Ofloxacin seems to be able to prevent (postoperative) meningitis, even with grampositive Cocci.

Adenoma↗
PubMed1990

Acute changes in the dynamics of the cerebrospinal fluid system during experimental subarachnoid hemorrhage.

Early changes in intracranial pressure (ICP), ICP volume index, and resistance to absorption of cerebrospinal fluid induced by experimental subarachnoid hemorrhage were studied in cats. After SAH, the ICP was slightly elevated, and there was a decrease in the buffering capacity of the intracranial space and a sharp rise in outflow resistance. During infusion of blood into the cisterna magna with a constant infusion rate, an extensive increase in ICP could be demonstrated in contrast to the infusion of saline, which caused only slight elevation of ICP. Furthermore, during blood infusion, the ICP level did not reach a plateau phase of pressure, as was demonstrated during infusion of saline. It is suggested that the marked increase in ICP during blood infusion into the subarachnoid space is caused by intracranial volume loading and the simultaneous increase in cerebrospinal fluid outflow resistance. It is concluded that the reported relationship between increased cerebrospinal fluid outflow resistance and increased ICP supports the hypothesis of a strong increase in ICP during subarachnoid hemorrhage in human subjects.

Animals↗
PubMed1990

[Cerebrospinal fluid dynamics in experimental subarachnoid hemorrhage].

To investigate the acute effects on intracerebral pressure, intracranial reserve capacity and CSF absorption resistance, a subarachnoidal haemorrhage was induced experimentally in a cat by bolus injection or continuous infusion of autologous blood into the cisterna magna. Intracisternal bolus injection resulted in a brief steep increase in intracranial pressure. 30 or 60 minutes after the haemorrhage the median intracranial pressure is slightly increased, the reserve capacity markedly reduced and the CSF absorption resistance considerably enhanced. During intracisternal blood infusion there is a continuous intracerebral pressure rise that persists to the end of the infusion and decrease again within a short time. This intracranial pressure behaviour is due to the simultaneous reduction of intracranial reserve capacity and the increase in CSF absorption resistance during the blood infusion.

Animals↗
PubMed1990

[Microsurgery, laser-assisted cranial nerve anastomosis. An experimental study].

Recently the milliwatt-CO2-laser has been introduced into the armentarium of experimental microsurgery for performing coaptation in peripheral nerves using the thermal effect of laser energy in order to achieve an atraumatic and reliable tissue bond. Experimental studies have shown that laser-assisted nerve coaptation are equal if not superior to conventional techniques in the reduced incidence of neuroma formation as well as the regenerative capacity. In this experimental study we have investigated if the CO2-laser working in the milliwatt range can be successfully applied for performing anastomosis of cranial nerves. The right oculomotor nerve in cats was microsurgically explored along the lateral temporal fossa from its exit at the brain stem to its entrance into the rudimentary cavernous sinus. Following division of the nerve with microscissors the nerve ends were loosely approximated. Thereafter welding of the cut nerves was performed with the CO2-laser (Cooper Laser Sonics, Model 860) using a power of 80-90 milliwatts, a spot-size of 150 microns and single bursts of laser energy. Complete welding of the cut nerve ends took about one to two minutes after which the surgical wound was closed. All experimental animals were observed for a period of 12 weeks after which they were sacrificed and the welded oculomotor nerve was removed for histological examination. Functional recovery of the III. nerve during the observation period was demonstrated by examination of the resting diameter of the pupil as well as by its reaction to direct stimulation with light. Morphological regeneration of the operated nerves could be demonstrated by histological studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1989

Ultrastructural changes of the basilar artery following experimental subarachnoid haemorrhage. A morphological study on the pathogenesis of delayed cerebral vasospasm.

Recent experimental studies have shown, that the endothelium of cerebral vessels undergoes significant changes after subarachnoid haemorrhage which may lead to biochemical changes at the endothelial surface with disturbance of the delicate homeostasis of vasodilating and vasoconstricting mechanisms which are thought to be responsible for preservation of the tones of the cerebral vasculature. Ultrastructural studies incorporating different forms of microscopic observations of the endothelium after SAH representing a prerequisite for further investigations on the pathogenesis of cerebral vasospasm are scarce. The experimental study was performed in order to investigate and define more precisely the pathomorphological changes at the endothelial surface of the basilar artery of dogs after experimental SAH. Two separate injections of autologous blood into the cisterna magna within 72 hours resulted in extensive angiographic narrowing of the diameter of the basilar artery of all animals. Histological studies of the basilar artery including light microscopic, transmission electron microscopic, scanning electron microscopic and freeze cracking microscopic examinations demonstrated severe pathomorphological changes at the endothelial surface. These consisted mainly of infolding and corrugation of the endothelium, disorientation and desquamation of endothelial cells as well as of vacuolation and ingrowth of fibrous tissue between the endothelial and muscular layer. No pathomorphological changes could be observed in the muscular layer. As the described post-haemorrhagic ultrastructural changes of the endothelium cerebral vessels in spasm are likely to represent the morphological basis of the delayed form of cerebral vasospasm future research on its pathogenesis should primarily focus on the structural and biochemical taking place at the endothelial surface of the cerebral vasculature after SAH.

Animals↗
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↗
PubMed1979

The protective effect of steroid treatment on lysosomal enzymes after cold lesion of the cat brain.

The effect of posttraumatic steroid treatment (6-methylprednisolone) on the stability of lysosomal membranes in the cat brain is studied. The share of free activity of the lysosomal enzymes beta-glucuronidase and N-acetylhexosaminidase indicates the grade of membrane stability. The results demonstrate an increased stability of lysosomal membranes in grey as well as in white matter after posttraumatic steroid treatment. This regarded as an important aspect of the protective effects of steroid treatment in posttraumatic brain edema.

Animals↗