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H J Reulen

Publications and source records attributed to H J Reulen.

At least 19 recordsLinked to original sources
PubMed1992

Are there typical localisations of lumbar disc herniations? A prospective study.

A prospective intra-operative analysis of the location of lumbar disc herniation was performed in 131 patients with verified 54% contained (incomplete) and 46% non-contained (complete) lumbar disc herniations. Bulging discs or protrusions are not included in this study. Complete disc herniations occurred more frequently in the upper lumbar spine. The localization of the lumbar disc herniations within its segment showed no correlation to the affected level. 64% of the disc herniations were located medio-laterally, 20% laterally, 12% within or lateral of the intervertebral compartment and 5% in the midline. Nearly one third of all herniations were found at the level of the disc space. Medio-lateral disc herniations were displaced more often in a caudal direction, lateral herniations were found displaced upwards and downwards with similar frequency while extraforminal herniations migrated significantly more often in a cranial direction. The pathomechanism and anatomical pathways of disc fragment migration are discussed on the basis of a new concept of the anterior extradural space.

Adult↗
PubMed1992

Subcortical topography and proportions of the pyramidal tract.

The pyramidal tract (PT) was dissected in 30 normal human hemispheres according to the method of Klingler. The various dimensions as well as the cerebral landmarks were studied. The pyramidal tract is built up like a fan in the white matter by a thin layer of fibers of 2.8-3.5 mm in thickness. The fibers converge toward the internal capsule to a solid fiber tract with a lateral and apdiameter of 7.8 +/- 1.6 mm and 17.5 +/- 2.1 mm, respectively. This configuration of the PT presents different possibilities of damage during surgery. The evaluation of the three-dimensional course of the PT is possible by using three cerebral landmarks, the precentral gyrus, the entrance into the internal capsule and the posterior limb of the internal capsule. Their topography is described. Additionally the pyramidal tract can be defined medially by the sulcus cinguli and the roof of the lateral ventricle and laterally by the superior sulcus circularis Insulae. The possible displacement of the PT by space occupying lesions and the intra-operative orientation is discussed.

Adult↗
PubMed1992

Safe surgery of lesions near the motor cortex using intra-operative mapping techniques: a report on 50 patients.

In 50 patients lesions located in or adjacent to the motor strip were microsurgically removed with the help of intra-operative electrophysiological mapping of the sensorimotor cortex. Mapping consisted of cortical stimulation and/or recording of somatosensory evoked potentials. Depending on the patient's pre-operative neurological status, surprisingly good results could be achieved: The surgery resulted in increased permanent sensorimotor deficit in only 4% of cases and in improved neurological status in 30% of cases. It is concluded that surgical removal of centrally located lesions using a microsurgical technique and intra-operative mapping of the motor cortex is safe and permits extensive or radical resection of lesions, even those in the motor cortex itself.

Adult↗
PubMed1992

The relationship of blood flow velocity fluctuations to intracranial pressure B waves.

Intracranial pressure (ICP) and continuous transcranial Doppler ultrasound signals were monitored in 20 head-injured patients and simultaneous synchronous fluctuations of middle cerebral artery (MCA) velocity and B waves of the ICP were observed. Continuous simultaneous monitoring of MCA velocity, ICP, arterial blood pressure, and expired CO2 revealed that both velocity waves and B waves occurred despite a constant CO2 concentration in ventilated patients and were usually not accompanied by fluctuations in the arterial blood pressure. Additional recordings from the extracranial carotid artery during the ICP B waves revealed similar synchronous fluctuations in the velocity of this artery, strongly supporting the hypothesis that blood flow fluctuations produce the velocity waves. The ratio between ICP wave amplitude and velocity wave amplitude was highly correlated to the ICP (r = 0.81, p less than 0.001). Velocity waves of similar characteristics and frequency, but usually of shorter duration, were observed in seven of 10 normal subjects in whom MCA velocity was recorded for 1 hour. The findings in this report strongly suggest that B waves in the ICP are a secondary effect of vasomotor waves, producing cerebral blood flow fluctuations that become amplified in the ICP tracing, in states of reduced intracranial compliance.

Adolescent↗
PubMed1992

[Neurosurgical treatment of lumbar stenosis. A review of the literature].

Low back pain and claudicatio spinalis are typical for spinal stenosis. Neuroradiological diagnosis is best accomplished by a myelogram. The operative results in patients with a lumbar spinal canal stenosis are successful in 85.5%. Radicular pain responds better than lumbar pain. Severe complications such as new persistent neurological deficits are rare. If the operation is performed early the results are usually better than with delayed surgery. The decompression should be adapted to the type and extent of the stenosis. Additional removal of the disc as well as severe damage to the facet joints increases the risk of postoperative instability.

Follow-Up Studies↗
PubMed1991

"Isthmic" spondylolisthesis--an analysis of the clinical and radiological presentation in relation to intraoperative findings and surgical results in 72 consecutive cases.

72 patients with isthmic spondylolisthesis have been analyzed prospectively with respect to their clinical presentation, radiological and intraoperative findings, operative techniques and surgical results. Excellent, good and satisfactory results have been obtained in 59 (82%), 10 (14%) and 3 patients (4%), respectively, by use of microsurgical techniques in combination with Louis-plate-fixation in Grade I and double arthrodesis/Cotrel-Dubousset-instrumentation in Grade II spondylolisthesis.

Adolescent↗
PubMed1991

"Standard" microsurgical lumbar discectomy vs. "conservative" microsurgical discectomy. A preliminary study.

The "conservative" microsurgical lumbar discectomy described by Williams for the treatment of herniated lumbar disc is compared in a retrospective study with the standard microsurgical technique of Caspar and Loew. In order to enable such a retrospective comparison, a special randomization had to be chosen. The data concerning outcome are based on a questionnaire, in which the patient can describe his actual health situation. The result in the group of 56 patients operated on by the Williams technique with a mean follow-up of 27 months is excellent or good in 89% vs. 74% in the standard technique group. Reoperations due to a recurrence were identical in both groups (3.6% and 3.9%).

Adult↗
PubMed1990

Fluid flow rates in human peritumoural oedema.

Five patients with various types of brain tumours were infused with x-ray contrast material in a schedule designed to maintain a constant plasma concentration of tracer over a period of 3 hours. CT scans from an equatorial section of the tumour were taken at frequent intervals the first hour; then at 2 and 3 hours, and when possible up to 14 hours. Two different mathematical models-1. simple diffusion, and 2. transport by bulk flow plus diffusion were used to analyze the changes in tracer amount along profiles placed radially from the tumour center into the oedematous white matter. We found that the simple diffusion model could not account for the spread of contrast material in 3 cases. Adding bulk flow transport gave a very good fit to the measurements, also for the late scans. This model gave bulk flow rates of 0.0005 to 0.005 ml cm-2 min-1 for the extratumoural tissue close to the tumour, and values from 0.25 to 0.55 for the extracellular space in this region. We conclude that the peritumoural tissue is "perfused" by oedema fluid at relatively high flow rates and that this flow transports tracer and other components of plasma into the extracellular space.

Body Fluids↗
PubMed1990

Early prognosis of supratentorial grade 2 astrocytomas in adult patients after resection or stereotactic biopsy. An analysis of 50 cases operated on between 1984 and 1988.

50 adult supratentorial low-grade astrocytomas operated upon between 1984 and 1988 were analysed retrospectively with respect to postoperative condition and progression-free survival. Pilocytic lesions were excluded. In 32 instances the tumour was macroscopically completely removed and partially in 4. In 14 cases a stereotactic biopsy was performed only. 10 patients received postoperative radiotherapy with 55 to 65 Gy. 1 patient died perioperatively from pulmonary embolism. 39 patients could resume their previous activities after discharge from the hospital, 10 were significantly disabled by neurological deficit, reduced neuropsychological performance or medically intractable epilepsy. Postoperatively, most patients required continuous anti-epileptic medication, 10 recurrences or tumour progressions of incompletely removed or merely biopsied lesions were observed within the mean follow-up period of 22 months. All recurrences after gross total removal, that were reoperated, had progressed to a malignant glioma. Of the prognostic tumour characteristics analysed, a histologically well-delineated tumour demarcation was most clearly associated with a favourable prognosis. Concerning treatment modalities, gross total resection was associated with a favourable prognosis. Radiotherapy was associated with an unfavourable outcome but this is probably due to selection of otherwise unfavourable cases.

Adolescent↗
PubMed1990

Early aneurysm surgery and preventive therapy with intravenously administered nimodipine: a multicenter, double-blind, dose-comparison study.

A European, multicenter, prospective, randomized, double-blind, dose-comparison study on preventive therapy with intravenously administered nimodipine was performed to evaluate the efficacy and tolerability of two different doses: 2 and 3 mg/h. Two hundred four patients fulfilled the criteria for enrollment in the study: surgery within 72 hours after the last subarachnoid hemorrhage, and age between 16 and 72 years. All patients who had Hunt and Hess grades of I to III were operated upon; patients who had poor Hunt and Hess grades (IV-V) were operated on according to the surgeon's choice. This treatment regimen was associated with a low incidence of delayed neurological dysfunction with no significant difference between the two dosage groups: three patients (1.5%) remained severely disabled and two (1%) moderately disabled due to vasospasm with or without additional complications. Among the patients with Hunt and Hess grades of IV or V, the long-term outcome was favorable (good-fair) for 40% and unfavorable for 60%. Among the patients with grades of I to III, the long-term outcome was favorable for 89% and unfavorable for 11%.

Dose-Response Relationship, Drug↗
PubMed1990

[Extreme lateral lumbar intervertebral disk displacement. Incidence, symptoms and therapy].

Upper lumbar nerve root compression or a femoralgia is often caused by extreme lateral lumbar disc herniation. This type of lumbar disc herniation compresses the nerve root inside or laterally to the intervertebral canal, while mediolateral disc herniations squeeze it in the lateral recess. Pain radiating obliquely over the thigh is the dominant clinical symptom. Bending the body to the ipsilateral side usually increases the pain. When neurologic signs are present, motor deficits tend to be more prominent than sensory and the deficits never affect more than one nerve root. Most frequently a weakness of knee extension occurs.

Humans↗
PubMed1990

A computed tomography study on formation, propagation, and resolution of edema fluid in metastatic brain tumors.

Propagation of contrast medium, which extravasated from small metastatic brain tumor, was imaged via CT. By maintaining a constant blood level of the contrast medium by prolonged infusion of 200 ml of 60% meglumine amidtrizoate for 3 hr and thus maintaining a constant passage of contrast labeled edema fluid into the peritumoral extracellular space, the spread of the newly formed edema fluid can be imaged by repeated CTs as a gradually expanding peritumoral circular enhancement into the neighboring white matter. Four patients with small metastatic brain tumor were investigated. CT scans were taken at identical levels 1.5, 3, 6, 9, and 12 hr after start of contrast infusion. After 4 to 7 days of dexamethasone treatment (0.15-0.25 mg/kg/day), the examination was repeated. The area of the expanding circular enhancement was planimetrically measured. From these values, the increase in radius per hour, respectively, in volume per hour were calculated assuming a spherical geometry. These data enabled a determination of the formation rate of edema fluid, of the speed of edema propagation, and of the resolution rate of edema fluid during tissue passage. The formation rate of edema fluid amounted to 0.6 to 3.2 ml/hr depending on tumor diameter and was reduced by about 30% after dexamethasone treatment. Edema fluid traveled 4.8 mm during the first 180 min and 1.9 mm during the consecutive 90 min. The resolution rate of edema fluid during tissue passage amounted to 0.05 ml/hr/cm3 white matter before dexamethasone treatment.

Brain Edema↗
PubMed1989

Radical resection of superior sagittal sinus meningioma with venous interposition graft and reimplantation of the rolandic veins. Case report.

A case of a 48 year old women is reported in whom a haemangiopericytic meningioma involving the middle third of the superior sagittal sinus was radically excised. The sinus was replaced by a saphenous vein graft and the Rolandic veins were reinserted. During clamping of the sinus the patient was heparinized and hypothermia, hypotension and barbiturates were used to prevent swelling of the brain. The postoperative course was uncomplicated and patency of the graft was demonstrated 2 weeks after the operation by Doppler sonography performed through a midline burr hole. The technical details of the operation and the pertinent physiology of cerebral venous flow are discussed.

Cranial Sinuses↗
PubMed1989

CT-observations of the intra- and extracanalicular disc herniation.

A retrospective analysis of 45 patients with intra- and extracanalicular lumbar disc herniations (ICDH, ECDH), collected over a 3 year period, is presented. When an intra- or extracanalicular DH was suspected, 1.5 mm axial cuts were made with a GE9800 from the cranial pedicle through the intervertebral canal to the pedicle of the lower vertebral body. Constructions were then made in coronal and paraxial planes to identify the pathology and its relation to the nerve root. 47% of all ICDH and ECDH were found at the level L4/5, 24% each at the levels L3/4 and L5/S1 respectively and 4% at the level L2/3. In 78% of our patients, the disc fragment was extruded and found well above the level of the disc space, in 22% at the level of the disc space. The coronal reformated views were in general better for demonstrating the course of the compressed nerve root at the levels L2/3-L4/5, while at L5/S1 the paraxial reformated view may yield better images. The distance from the midline of the spinal canal to the medial and lateral edge of the ECDH averages 16.4 +/- 3.4 and 33.3 +/- 3.6 mm and in some cases the lateral edge was found 39-44 mm from the midline. Pitfalls in the diagnosis of ECDH may be caused by scar tissue, sometimes by an upwardly displaced nerve root or ganglion and, very rarely, by a neurinoma. Pitfalls in therapy, i.g. false negative intraspinal exploration in cases of intra- or extracanalicular disc herniations or exploration of the wrong intervertebral canal, may result due to insufficient neuroradiological analysis or from insufficient consideration of the anatomical situation by the neurosurgeon.

Aged↗
PubMed1989

Growth of aneurysms can be understood as passive yield to blood pressure. An experimental study.

The strength of aneurysm walls obtained intraoperatively or at autopsy immediately after death was evaluated by measurements of the force response to one-directional stretch and compared to the walls of intracranial arteries. The maximum stress that aneurysm tissue could tolerate was found slightly lower than in arteries, which is most probably due to the amount of immature forms of collagen. The stress resistance of aneurysms and arterial tissue decayed over a period of several hours. The relaxation curve could be approximated by the sum of 2 exponential terms. The half decay times of these terms were found identical in aneurysms and arteries, they appear to be collagen characteristics. The strength measured in vitro was compared to the stress in vivo, which was calculated on the basis of blood pressure and aneurysm radius. The stress tolerated by aneurysm walls over a period of 24 hours was found to be in the range of the stress that is imposed in vivo by the mean blood pressure. Arteries resisted stresses corresponding to pressures 10 to 20 times higher than physiological values. The thickness of the aneurysm walls correlated with the aneurysm radius in a linear fashion. It is suggested that aneurysm growth can be understood as passive yield to blood pressure, and reactive healing and thickening of the wall with increasing aneurysm diameter.

Biomechanical Phenomena↗
PubMed1989

Meningoradiculoneuritis mimicking vertebral disc herniation. A "neurosurgical" complication of Lyme-borreliosis.

We report on 3 patients with meningoradiculoneuritis (MRN) due to Lyme-borreliosis (LB), which presented clinically as vertebral disc herniation. In 2 cases the underlying infection was discovered only after unsuccessful neurosurgical treatment. In the differential diagnosis between MRN and disc herniation the following criteria are suggestive of MRN and should raise suspicion of a non-discogenic aetiology: History of tick bite or erythema chronicum migrans, fever or general malaise, mono- or oligoradiculopathy with absent or insignificant lumbar pain and complaints of a burning character of the radiating pain. In suspicious cases we recommend blood investigations including antibody determination against borrelia burgdorferi and CSF investigations including cell count and cytology, protein and glucose determination, nephelometry and isoelectric focusing to exclude MRN and other conditions that may mimic disc herniation.

Aged↗
PubMed1989

Diagnostic approach in instability and irritative state of a "lumbar motion segment" following disc surgery--failed back surgery syndrome.

A diagnostic protocol for patients with suspected instability and irritative state of a "lumbar motion segment" following lumbar disc surgery is presented and the results of internal fixation are analyzed. In this group of patients the clinical picture and physical signs may be quite distinct and suggestive of instability and irritation of a "lumbar motion segment", however, in isolation, they do not allow to decide upon surgery. Radiological studies favour a decision for surgery only in cases with an obvious instability of a "motion segment". Anaesthethizing the articular nerves permits localization of the irritable segment and non-surgical therapeutic decisions (thermocoagulation) can only be taken in cases of an isolated facet-syndrome when instability has been ruled out. The trial plaster jacket holds the most important position with respect to the indication for internal fixation as demonstrated by the conformity of the results of the plaster jacket and the results of surgery. After internal stabilization excellent, good, satisfactory and moderate results were obtained in 20, 3, 1 and 1 patients, respectively.

Anesthesia, Spinal↗