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Biomedical subjects

A Harders

Publications and source records attributed to A Harders.

At least 55 records · Page 3Linked to original sources
PubMed1993

Large thoracocervical intraspinal neuroma: unusual clinical and neuroradiological findings.

The clinical and radiological findings of a giant cystic intraspinal cervical tumour are presented. Symptoms and signs suggesting a polyneuropathy were misleading. On myelography the tumour appeared as a solid mass, but its size was distinctly underestimated. MRI demonstrated the true extent (from C4 to T4) and the cystic structure of the tumour. The histo-pathological diagnosis was fibrillary neuroma (WHO grade I).

Aged↗
PubMed1993

Frameless stereotactic drainage of intracranial abscesses.

Our preliminary experience is presented in the use of the Aachen Computer-Assisted Surgery device for frameless stereotactic puncture and drainage of intracranial abscesses through a 2.1-mm twist-drill hole. The apparatus and technique are described, along with the results of its use in 2 patients. Intraoperatively the semiactive system presents a schematic display of the drainage probe projected into a 3D model of the situs on the monitor screen corresponding to the instrument's position. As the surgeon directs the probe into the abscess the corresponding section is displayed. Thereby drainage is easily achieved under visual control.

Adult↗
PubMed1993

Correlation between clinical, angiographic and transcranial Doppler sonographic findings in patients with moyamoya disease.

Nine patients with Moyamoya disease were followed by the authors between 1982 and 1991. The patients were investigated with transcranial Doppler sonography (TCD), angiography and clinically. Two patients were treated conservatively. Bilateral extra-intracranial (EC-IC) anastomosis was performed in 4 patients; in 2 patients bypass surgery was performed unilaterally. One patient with an aneurysm of the carotid artery presented a subarachnoidal haemorrhage. There was a good correlation between TCD and angiographical findings in all patients. In four patients indication for bypass surgery was established by TCD. All patients who underwent EC-IC bypass surgery improved clinically; the symptoms disappeared in three patients and improved markedly in two patients. Transcranial Doppler sonography is proven to be a reliable atraumatic tool in diagnosis, indication for treatment and postoperative follow-up in patients with moyamoya disease.

Adult↗
PubMed1993

[Nosocomial infections in a neurosurgical intensive care unit].

The occurrence of nosocomial infections in 1017 consecutive patients seen in a neurosurgical intensive care unit (ICU), over a period of 18 months is reported. The frequency of infections is low, which may possibly be due partly to the short stay in the ICU. Close interdisciplinary cooperation is stressed as an important factor in limiting infections. BACKGROUND. The aim of this study was to analyse the nosocomial infections in a neurosurgical intensive care unit over a period of 18 months, emphasizing localization and cause of infection, in order to adapt treatment and to take preventive measures. From 15% to 27% of patients treated in ICUs acquire nosocomial infections. In Germany this means 500,000-800,000 patients a year, and the annual costs related to nosocomial infections are estimated at 1.7 billion Deutschmarks. PATIENTS AND METHODS. In all, 1017 consecutive patients were evaluated. The patients were divided into two groups, depending on the duration of treatment in the ICU: Patients who remained for less than 48 h (1017 patients) Patients who were treated for a period exceeding 48 h (314 patients) The evaluation was performed retrospectively from the medical documentation. Criteria for registration are those of the Centers for Disease Control (Atlanta 1988). When more than one infection was diagnosed, each was considered as a new infection, regardless of the bacteria involved. Among the 314 patients who were in the ICU for more than 48 h a total of 114 nosocomial infections were recorded. The frequency of infection referred to all patients treated during that time (n = 1017) was 11.2%, while the frequency among those who were treated for longer than 48 h was 36.3%. Most infections (38.6%) affected the respiratory tract, followed by infections of the urinary tract. Of the bacteria determined 56.7% were gram-negative. In this group E. coli was the most frequently found (29.8%). In the group of gram-positive bacteria, S. aureus was diagnosed in 56.3% of cases. Twelve (16%) of the infected patients died and lethality referred to all patients was 8.6%. DISCUSSION. Compared with other studies, this study revealed a low the infection rate, at 11.2%. This can be explained partly by the short stay in this ICU (mean 3.7 days) and partly by the retrospective method of registration and the particular medical characteristics of neurosurgical patients. The well-known general risk factors for infection, such as age, mechanical ventilation, continuous catheterization of the bladder, and long duration of stay, are also found in neurosurgical ICUs. It is quite difficult to determine to what extent nosocomial infections prolong the treatment necessitated by the primary neurosurgical disease. We were not able to extrapolate the influence of immunosuppressant treatment on the appearance of nosocomial infections, as almost all patients in this study were receiving steroids. This study underlines the necessity of interdisciplinary cooperation between neurosurgeons, anaesthesiologists, microbiologists and nurses in neurosurgical ICUs, where most patients staying longer than 48 h are immunosuppressed and ventilated and thereby particularly at risk of nosocomial infections.

Costs and Cost Analysis↗
PubMed1992

Experience with the infratentorial supracerebellar approach in lesions of the quadrigeminal region, posterior third ventricle, culmen cerebelli, and cerebellar peduncle.

We report about our experience with the infratentorial supracerebellar approach in 23 patients operated on for lesions located in the posterior part of the third ventricle, quadrigeminal plate, culmen cerebelli and cerebellar peduncle. Three patients had transient worsening of their deficits immediately after surgery. Three patients developed haemorrhages postoperatively requiring surgical evacuation. One of them died. None of the patients developed specific complications which could without any doubt be attributed to the approach. We concluded that in combination with intra-operative CSF drainage and the sitting position the infratentorial supracerebellar approach allows safe access to lesions situated in an area limited by the posterior part of the third ventricle, the fastigium level and both cerebellar peduncles.

Adolescent↗
PubMed1992

Computer assisted localizer for planning of surgery and intra-operative orientation.

There is discrepancy between the exact representation of anatomical structures and tumours in the CT or MRI scan and the more or less accurate intra-operative localisation methods based mostly upon landmarks of the skull and extracerebral space and visible abnormalities of the cerebral surface. To overcome these problems of exact intra-operative localisation a Computer Assisted Localizer (CAL) is presented which allows precise intra-operative orientation without these aids. It consists of a mechanically articulated arm with six degrees of freedom with a high precision digital incremental and an image processor for 3 D data of the head. MRI and/or CT investigation is done pre-operatively with four reference markers fixed on the patient's head. They are visible on the CT or MRI slices and are used as reference points during surgery for adjustment of the device. The co-ordinates of the digitalizer arm tip are projected into the corresponding axial, sagittal and coronal CT slices so that the system simultaneously presents three orthogonal multiplanar CT reconstructions with a reticule indicating the position of the tip of the arm. As the surgeon directs the arm to the region of interest the corresponding CT slices are displayed on the monitor at a rate of 20 slices/sec determined by the motion of the arm. The accuracy of measurement of the device itself lies within 1 mm. The accuracy is somewhat reduced however by the thickness of CT or MRI slices (routinely 2 mm slices were taken) and by deviations of the reference markers on the skin surface which amount up to 3 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Limits of the transoral approach in craniospinal malformations.

Over a 15-year period, 15 patients with craniospinal malformations were operated on using the transoral route. Ten patients had basilar impression and five had atlantoaxial dislocation; nine patients had associated lesions. Patients treated with reposition and dorsal fusion recovered well without ventral decompression. We found that transoral odontoidectomy is suitable as a primary decompressing measure only in ventral compression or nondislocated atlantoaxial conditions.

Journal Article↗
PubMed1991

Successful treatment of a haemangioblastoma in a 95 year-old patient. Case report.

Haemangioblastomas located in the posterior fossa have rarely been described in patients older than 60 years of age. The authors report a case of a 95 year-old man who presented with an obstructive hydrocephalus secondary to a posterior fossa tumour. Computed tomography and angiography suggested intracerebellar metastasis. Despite the advanced age of the patient and his poor general condition, surgery was performed with the patient in a supine position. A haemiangioblastoma was found and completely removed. The postoperative course was without complications. This case demonstrates that the combination of modern anaesthesia, supine operating position, and the use of microsurgical techniques allow successful operations on the posterior fossa even in very old patients.

Aged↗
PubMed1991

Clinical significance of computed tomography in early aneurysm surgery.

The significance of computer tomographic findings for the analysis of complications or the course and prognosis after early aneurysm surgery was analyzed on the basis of 100 patients consecutively operated on for ruptured cerebral aneurysms. Intracerebral or extended intraventricular hematomas were a poor prognostic sign. An acute hydrocephalus had a negative effect only on the early course but not on the final results. Nearly all (94) of the patients presented postoperatively with a cerebral volume increase either by CSF release, edema, and/or vasoparalysis. A correlation with the final result could not be observed. Twenty-two patients presented with ischemic infarction in the postoperative CT scan, one had hemorrhagic infarction. In 19 of the 22 cases the cause of the infarction could be related to the surgical trauma. In 10 cases it remained asymptomatic. In only one case vasospasm was responsible for a symptomatic infarction. The findings show that early surgical repair of a ruptured cerebral aneurysm is an effective method to prevent rebleeding and ischemic infarction by vasospasm. The hemorrhage and the operation, however, are followed by a large number of visible morphological lesions in the CT scan.

Adult↗
PubMed1989

Transient stenoses and occlusions of main cerebral arteries in children--diagnosis and control of therapy by transcranial Doppler sonography.

Flow disturbances in main cerebral arteries may cause severe neurological symptoms. Using transcranial Doppler sonography (TCD) the blood flow velocities in the basal cerebral arteries (BCA) can be recorded at any age. Transient stenoses or occlusions of main cerebral arteries were detected in 11 children by this method and confirmed by other techniques. Vasospasm produced a marked increase in flow velocities in the affected arteries which was reduced by nimodipine, the calcium channel blocker. Vasospasm also occurred in severe bacterial meningitis. In acute hemiplegia due to cerebral arterial obstruction no flow velocities could be recorded at the corresponding site. If distal branches were obstructed reduced flow velocities were found proximally. Increased flow velocities or reversed flow in anastomoses indicated the collateralization. The transient nature of the occlusions was shown by repeated recordings. TCD is a reliable, noninvasive and rapidly available technique for diagnosing or excluding transient flow disturbances in the main cerebral arteries as the cause of neurological symptoms in children. It indicates the necessity and most advantageous stage for therapy.

Adolescent↗
PubMed1988

The microvascular Doppler--an intraoperative tool for the treatment of large and giant aneurysms.

One of the problems especially associated with large and giant aneurysms is the control of the patency of the parent artery and the exclusion of the aneurysm. While the exclusion can be tested by puncture (which may sometimes be problematic), the patency can only be controlled by intraoperative angiography or recently, by microvascular intraoperative Doppler. The device we use has a high resolution and is equipped with probes as small as 0.3 mm with which all visible vessels with diameters of more than 0.1 mm can be investigated. Local stenoses above a diameter reduction of 40% can be easily detected by localized accelerations and changes in the pulse curves. Our recent experience with 11 giant and 13 large aneurysms has revealed marked discrepancies between an apparently well placed clip and an obviously open vessel on the one hand, and the haemodynamic reality revealed by the Doppler on the other. We were able to decide whether the flow was undisturbed, or whether there was an haemodynamically non-effective lumen reduction due to a tight clip, or if there was severe stenosis or a total occlusion. In five cases with severely disturbed flow after clipping, we had to change our strategy: we resected the aneurysms and sutured the neck, performed an end-to-end anastomosis, coated the aneurysm, or repositioned the clips. In cases in which we did not have full view of the neck, the Doppler guided us to a proper clip position. We conclude that especially for large and giant aneurysms, the microvascular interoperative Doppler is a valuable tool.

Adult↗
PubMed1988

Haemodynamic effectiveness of nimodipine on spastic brain vessels after subarachnoid haemorrhage evaluated by the transcranial Doppler method. A review of clinical studies.

The authors review the literature reports and own results of a double-blind study of the effectiveness of nimodipine on prevention or treatment of spasm of cerebral arteries following subarachnoid haemorrhage (SAH). Spasm has been evaluated using the transcranial Doppler method (TCD). The patients were divided into two groups which received 2 resp. 3 mg/h nimodipine. The clinical outcome and also the incidence of spasm of both of the groups were not different, but spasm was less severe in the 3 mg/h group.

Blood Flow Velocity↗
PubMed1988

Haemodynamic changes in arteriovenous malformations induced by superselective embolization: transcranial Doppler evaluation.

To reduce the intraoperative and postoperative complications in patients who suffer intracerebral arteriovenous malformations (AVM's), the slow reduction of the shunt flow to a brain perfusion flow has been tried by the use of several methods: microsurgical techniques, selective and superselective embolization, intraoperative embolization, staged operation. The risk of re-bleeding and intraoperative oedema increases in AVM's with two or more feeders. Our policy was to exclude such AVM's by primary superselective embolization. If there was only a small residual angioma, we tried to remove this by microsurgical techniques. The haemodynamics in AVM's could be examined by measuring the blood flow velocities in the feeding arteries and in the other parts of the circle of Willis by transcranial Doppler sonography (TCD). Signs of haemodynamic effective embolization could be measured by the reduction of flow velocities. After exclusion of an AVM the velocities in the brain and feeding arteries decreased to below normal values in the first days after the operation. In the feeding arteries this was due to the fact that the arteries were enlarged so that the velocity must be decreased when there was normal volume flow. The combination of superselective angiography and microsurgical resection of the residual angioma seemed to be the best way to treat AVM's which are fed by more than two arteries and which are 3 or more cm in diameter. TCD investigations were used to measure the haemodynamic changes before and after angioma superselective embolization and microsurgical operation.

Cerebral Angiography↗
PubMed1986

Nimodipine and early aneurysm operation in good condition SAH patients.

A prospective open multicenter study on the preventive effect of nimodipine on symptomatic vascular spasm was performed in 120 (consecutive) patients with aneurysmal subarachnoid haemorrhage (SAH). All patients underwent early surgery (i.e. within 72 hours post SAH) and were in neurological grades I-III in Hunt and Hess. Grade IV and V as well as patients with significant intracerebral haematoma are not included. On preoperative CT, SAH was mild in 28 cases, moderate in 56 and severe in 36 cases. 25 patients (21%) were in grade I, 63 patients (53%) in grade II and 32 patients (26%) in grade III. The ruptured aneurysm was located on the anterior cerebral artery complex in 57 patients, on the internal carotid artery complex in 35, on the middle cerebral artery in 24 patients and on the basilar artery in 4 patients. After occlusion of the ruptured aneurysm, the lipophilic calcium channel blocker nimodipine was administered in the following manner: Intraoperative, topical irrigation of the exposed arteries. Intravenous infusion until day 7-14 after SAH followed by peroral medication for another week. Nimodipine was well tolerated and neither significant hypotension nor any other adverse reaction attributable to the drug was observed. Ischaemic cerebral dysfunction of delayed onset with permanent neurological deficit occurred in 2 patients (2%). Another 8 patients showed transient ischaemic symptoms. At 6 months follow-up, 93% of the patients were classified as having made a full recovery, 16% as being minimally disabled, 5% as being moderately disabled and 3% as being severely disabled. Three patients had died. The present study supports the concept that preventive nimodipine treatment may reduce delayed ischaemic deficit in early aneurysm surgery.

Administration, Topical↗
PubMed1986

Intracerebral cavernous angiomas in magnetic resonance imaging.

The findings obtained by magnetic resonance imaging (MRI) in 8 cases of surgically and histologically confirmed intracerebral cavernomas are reported. Six of the malformations were located temporally, one was located on the floor of the fourth ventricle, and one in the parietal lobe. All of the 8 cavernomas could be clearly demarcated, both in the T2 weighted image and in the spin density image. They are demonstrated as inhomogeneous zones with high or no signals. The tumors had irregular contours, which were clearly set off from the surrounding parenchyma. In 2 cases, the hemorrhage later detected surgically could already be assumed from the MR image. In 3 cases, zones with weak signals were found in the tumor, which were considered to be calcifications. One case of a vein with laminar flow could be established.

Adult↗
PubMed1985

Supratentorial space occupying lesions following infratentorial surgery early diagnosis and treatment.

Supratentorial complications of infratentorial surgery are rare. In the last 3 years we have operated on 187 patients with infratentorial lesions and have observed an incidence of 3.7% of supratentorial haemorrhages. Postoperative intracranial air, as shown by early postoperative CT control, was encountered mainly in a subdural frontal location and within the interhemispheric fissure. We performed no surgical decompression of the air accumulation because of the lack of clinical symptoms. Predisposing factors for the development of supratentorial complications remote from the surgical area are hypertonia, female sex, brain atrophy and preoperative shunting procedures. Measures to avoid these complications are discussed.

Adult↗
PubMed1985

Early aneurysm operation and vasospasm. Intracranial Doppler findings.

Modern ultrasonic Doppler systems enable us for the first time to carry out intraoperative and pre- and postoperative investigations of the circle of Willis. The application of Doppler in acute aneurysm surgery provided the following information: During the first 3 days following subarachnoid bleeding from a cerebral aneurysm, no signs of vasospastic reaction were found by Doppler sonography. Thereafter, 90% of all patients operated on in the acute stage demonstrated localized acceleration as a sign of vasospasm, despite prophylactic nimodipine treatment. Thirty-eight percent of the patients developed delayed ischemic deficits, which, however, were only transient. These results may indicate that early surgery and nimodipine prophylaxis may not prevent vasospasm but do reduce its consequences.

Adult↗