Christiaan Plets

Variable effects of explosive or gradual increase of intracranial pressure on myocardial structure and function.

BackgroundStudies done in potential donors for heart transplantation and in experimental animals have suggested that brain death can have major histopathological and functional effects on the myocardium. Methods and ResultsWe developed experimental models of brain death using dogs to study the hemodynamic and catecholamine changes, the extent of myocardial structural damage, and the recovery potential of donor hearts obtained from brain-dead donors. Brain death was caused by increasing the intracranial pressure (ICP) suddenly or gradually by injecting saline in an epidural Foley catheter. In a first series of experiments, dogs given a sudden rise in ICP (n=5) showed a hyperdynamic response and a 1,000-fold increase in the level of epinephrine after brain death. Histology revealed 93±2% of the myocardium to be severely ischemic. Dogs given a gradual rise in ICP (n=6) showed a lesser hyperdynamic response, almost 200-fold increase in the level of epinephrine after brain death, and mild ischemic damage to the myocardium (23±1%). In a second series, hearts obtained from brain-dead and non-brain-dead donors were transplanted in recipients, and the weaning and recovery potential were studied. All four recipients with hearts from non-brain-dead donors were weaned with good functional recovery. Also, all four recipients with hearts from brain-dead dogs given a gradual rise in ICP were weaned with only moderate functional recovery. However, only two of four recipients with hearts from donors given a sudden rise in ICP were weaned and showed poor functional recovery. ConclusionsOur results indicate that a sudden rise in ICP can cause irreversible myocardial damage.

CT and MRI of ruptured intracranial dermoids

SummaryTwo patients with ruptured intracranial dermoids, examined with both CT and MRI are reported. Clinical presentation was transient cerebral ischemia in one patient and acute meningeal signs in the other. CT scan showed typical fat density of the tumor and the subarachnoid space. On MRI both the tumor and the subarachnoid fat, were strongly hyperintense on T1-weighted images.

Natural history of petroclival meningiomas.

OBJECTIVEFor evaluation of the natural history of petroclival meningiomas, a cooperative retrospective study of 21 conservatively treated patients is reported. METHODSAll patients had petroclival meningiomas that were observed for at least 4 years, with regular clinical and radiological control examinations. The follow-up periods ranged from 48 to 120 months (mean, 82 mo; median, 85 mo). Functional evaluations were performed by using the Karnofsky index. Individual growth curves and rates were defined. RESULTSAge and sex distributions and presenting symptoms were comparable to those of other studies. During follow-up monitoring, radiological tumor growth was observed in 76% of the cases. With 63% of the growing tumors, there was functional deterioration. We performed statistical analyses of demographic features, radiological findings, and functional deterioration. Severe functional deterioration was observed to be statistically significantly associated with infratentorial growth and increased growth rates. A change in the growth pattern often preceded functional deterioration. CONCLUSIONThis study provides a better understanding of the natural course of petroclival meningiomas. The growth patterns of these tumors are unpredictable and variable. The exact factors influencing growth remain unclear. This study can contribute to the optimization of individual management of these tumors.

Bicycle-related head injury: a study of 86 cases

Within the framework of a bicycle helmet research program, we have set up a database of bicycle accident victims, containing both accident and clinical data. The database consists of a consecutive series of 86 victims of bicycle accidents who underwent a neurosurgical intervention in our hospital between 1990 and 2000. Data were obtained from police files, medical records, computed tomography head scans and a patient questionnaire. In only three victims, the wearing of a helmet was documented. In this study, the head injuries are analysed and the relation between the different types of head injuries and outcome is assessed. Forty-four accidents were collisions with a motor vehicle and 42 accidents were falls. Most impacts occurred at the side (57%) or at the front (27%) of the head. The most frequent injuries were skull fractures (86%) and cerebral contusions (73%). Age was negatively correlated with outcome (P = 0.0002 ) and positively correlated with the number (P = 0.00002) and volume (P = 0.00005) of contusions and the presence of subdural haematomas (P = 0.000001). The injuries with the strongest negative effect on outcome were: subarachnoid haemorrhage (P = 0.000001), multiple (P = 0.000005) or large ( P 0.0007) contusions, subdural haematoma (P = 0.001) and brain swelling (P = 0.002). A significant coexistence of these four injuries was found. We hypothesise that in many patients the contusions may have been the primary injuries of this complex and should therefore be considered as a main injury determining outcome in this study. We believe that such findings may support a rational approach to optimising pedal cyclist head protection.

Synovial Cyst at the C1-C2 Junction

Intraspinal synovial or ganglion cysts of the cervical spine are rare. We present the third reported case of a degenerative articular cyst of the upper cervical spine, involving the quadrate ligament of the odontoid process. Magnetic resonance examination reveals typical images. A new, more general terminology is proposed.

Gadolinium-enhanced MR imaging of cerebral venous angiomas with emphasis on their drainage

Gadolinium-enhanced MR was performed in 28 patients with 17 supratentorial and 11 cerebellar venous angiomas. The use of gadolinium allowed detection of 9 of 28 venous angiomas (32%) that were not visible before gadolinium or which were only recognized in retrospect. Before gadolinium the peripheral medullary veins that are typical for these venous malformations were only visualized in 4 of 17 (23%) supratentorial and in 5 of 11 (45%) cerebellar lesions, for a total of 9 of 28 (32%) venous angiomas. After intravenous administration of gadolinium these veins were seen in 27 of 28 (96%) venous angiomas. Extension of the lesions to the wall of the ventricles was seen in 24 of the 28, 16 of 17 supratentorial and 8 of 11 cerebellar, lesions after gadolinium. This information was missed on plain MR in 6 of these lesions. The type of venous drainage, either superficial or deep, could be determined by gadolinium-enhanced MR in all cases where angiography was available for comparison. Before gadolinium this information was not available in eight patients. The intravenous administration of gadolinium adds significant information in the MR study of venous angioma.

Craniofacial resection for anterior skull base tumours

SummaryThis study presents a series of 10 patients with anterior skull base tumours, treated by a team of neurosurgeons and head- and neck surgeons. The series included 7 malignant tumours of the nose and paranasal sinuses and 1 retinoblastoma, all with intracranial extension through the lamina cribrosa. There were also 2 patients with an anterior base meningioma, growing into the ethmoid sinus and the nasal cavity.8 tumours were resected by a combined bifrontal craniotomy and uni- or bilateral rhinotomy. In 2 cases a bifrontal craniotomy alone without facial incision sufficed. The skull base was closed with a pediculated pericranial flap and a split-thickness free skin graft underneath.There were no postoperative problems of wound infection, CSF-leakage or meningitis. Recurrent tumour growth or systemic metastasis occurred in 5 out of 7 patients with malignant tumours, 6 months to 2 years postoperatively.The related literature and especially questions of operative indications and technique, including different possibilities of closure and reconstruction of the skull base, are discussed.

Epidermoid tumours associated with lumbar punctures performed in early neonatal life

Three children (ages 5,7, and 12 years) with epidermoid tumours in the spinal canal, all of whom had a lumbar puncture during the early neonatal period, are reported. A considerable delay occurred from the first symptoms until the diagnosis was made. MRI of the lumbar spine was the method of choice in the diagnostic work‐up. All three cases were successfully surgically treated. The link between lumbar punctures and epidermoid tumours and the possible risk factors involved are explored. Because of the variable clinical presentation, the possibility of the existence of these tumours should be considered in the differential diagnosis.

Arterial hypertension in neurosurgical emergencies

The Cushing, or ischemic response, is a useful mechanism in intracranial hypertension because it restores normal cerebral perfusion pressure and cerebral circulation. In patients with acute intracranial hypertension due to mass-expanding lesions such as brain edema, hydrocephalus or brain tumor, cerebral perfusion pressure decreases and plateau waves occur. In experimental animals, spontaneous or induced arterial hypertension can compensate for the reduction of cerebral perfusion pressure. The interrelation between arterial pressure, intracranial pressure and cerebral perfusion pressure in an experimental model of hydrocephalus in dogs was investigated. Plateau waves were preceded by a decrease in cerebral perfusion pressure and a Cushing response was seen 5 to 15 seconds before abolition of the wave. Arterial hypertension, induced by intravenous infusion of Aramin, restored cerebral perfusion pressure and intracranial pressure became normal. Arterial hypertension appears to be an efficient stimulus to abort plateau waves. Hypertensive patients in whom subarachnoid bleeding develops from ruptured aneurysm are at high risk of bleeding again and need antihypertensive treatment together with drainage of cerebrospinal fluid. Induced arterial hypertension is the most effective treatment of vasospasm but increases the danger of aneurysmal rebleeding and can only be safe after clipping of the aneurysm. This is one of the strongest arguments for early operation on cerebral aneurysms.

Intraspinal juxta-facet cysts : a case of bilateral ganglion cysts

Juxta-facet cysts are relatively uncommon intraspinal lesions, causing radiculopathy, neurogenic claudication or myelopathy. To the best of our knowledge, only 4 cases of bilateral synovial or ganglioncysts were described. We report the 5th case of bilateral ganglioncysts of the lumbar spine. Generally, juxta-facet cysts should be differentiated from other intraspinal lesions, such as herniated discs, meningiomas and neurinomas. Correct preoperative diagnosis is necessary for adequate treatment, namely the (microscopic) resection of the cyst. After adequate treatment, complete recovery may be expected.