Esa Heikkinen

Relief of Epilepsy by Radiosurgery of Cerebral Arteriovenous Malformations

129 patients with inoperable cerebral arteriovenous malformations (AVM) were treated by stereotactic proton beam irradiation. Symptomatic epilepsy was present in 29 patients (22.5%) before the treatment. It was markedly relieved by the radiosurgery leading to cessation of the seizures in 16 patients, the persisting seizure-free follow-up period ranging from 2 to 8 years (mean 4.5 years). In no case was the epilepsy worsened by radiosurgery. The positive effect on epilepsy was not strictly dependent on the angiographic result, suggesting that the ionizing radiation by itself could lead to inhibition of epileptic activity around the AVM.

Epilepsy after operative treatment of ruptured cerebral aneurysms

SummaryA retrospective analysis of 183 consecutive patients operated on for ruptured cerebral aneurysms and surviving at least one year revealed appearance of postoperative epilepsy in 14 cases (8 per cent) on an average of 10 months (range 0–23 months) after the operation. Factors associated with the development of secondary epilepsy were localization of the aneurysm on the middle cerebral artery, temporary clipping intraoperatively, wrapping technique to treat the aneurysm, and vasospasm seen on the postoperative control angiogram. Intraoperative and/or postoperative ischaemia seems to be the crucial phenomenon favouring the development of epilepsy. Identification of the risk factors may help to focus the anti-epileptic prophylaxis in cases prone to develop seizures.

Classification and management of the slit ventricle syndrome

A total of 32 patients with overdrainage of CSF, fulfilling the radiological and clinical criteria for collapsed ventricles (“slit ventricles”), were classified into acute, subacute and chronic forms. The basis of classification into these categories was neurologic symptomatology. The majority (29 patients) originally had a ventriculoatrial shunt and 3 had ventriculoperitoneal shunts. Operative correction was performed in 23 patients (insertion of a high pressure valve in 18 and an antisiphon device in 5). Of these, 5 had acute, 10 subacute, and 6 chronic symptoms. Two patients without symptoms were operated on also. During the follow-up period, which varied from 2 to 11 months, no patient has shown recurrence of the original symptoms of the slit ventricle syndrome; two patients developed subacute signs and an antisiphon device was inserted in addition to the high-resistance valve. On the basis of this series, it is concluded that the slit ventricle syndrome can also develop in patients with an atrioventricular shunt and can be treated by preventing further overdrainage of CSF. Though the results are acceptable by present methods, the need for a servo-regulated shunt persists. The surgical correction should preferably be performed before the acute phase. A flowchart is presented for management of a child with suspected slit ventricles.

Cardiac autonomic control in patients with refractory epilepsy before and during vagus nerve stimulation treatment: a one-year follow-up study.

Summary:  Purpose: To elucidate possible effect of vagus nerve stimulation (VNS) therapy on interictal heart rate (HR) variability in patients with refractory epilepsy before and after 1‐year VNS treatment.

Stereotactic radiotherapy instead of conventional epilepsy surgery. A case report.

SummaryA case report is made on a 29 year old male suffering from drug resistant epilepsy with a left temporal focus and normal neuroradiological findings. Instead of the conventional partial temporal resection, the focus was stereotactically irradiated in five fractions using a standard linear accelerator (6 MeV), to a total dose equivalent of 10 Gy in a single shot. Two months after the treatment the frequency of seizures decreased and the patient has been free of attacks since the seventh postirradiation month, up to 27 months by now, and in excellent condition. Noninvasive Stereotactic radiotherapy may turn out to be a rational way to eliminate an epileptic focus.

Increase of collagen synthesis and deposition in the arachnoid and the dura following subarachnoid hemorrhage in the rat.

Arachnoidal fibrosis following subarachnoid hemorrhage (SAH) has been suggested to play a pathogenic role in the development of late post-hemorrhagic hydrocephalus in humans. The purpose of this study was to investigate the rate of collagen synthesis in the arachnoid and the dura in the rat under normal conditions and to study the time schedule and the localization of the increased collagen synthesis following an experimental SAH. We found that the activity of prolyl 4-hydroxylase, a key enzyme in collagen synthesis, was 3-fold higher in the dura than that in the arachnoid and was similar to the activity in the skin. We then induced SAH in rats by injecting autologous arterial blood into cisterna magna. After SAH, we observed an increase in prolyl 4-hydroxylase activity of the arachnoid and the dura at 1 week. At this time point the enzyme activity in both tissues was 1.7-1.8-fold compared to that in the controls and after this time point the activities declined but remained slightly elevated at least till week 4. The rate of collagen synthesis was measured in vitro by labeling the tissues with [(3)H]proline. The rate increased to be 1.7-fold at 1 to 2 weeks after the SAH in both of the tissues. Immunohistochemically we observed a deposition of type I collagen in the meninges at 3 weeks after the SAH. SAH is followed by a transient increase in the rate of collagen synthesis in the arachnoid and, surprisingly, also the dura. Increased synthesis also resulted in an accumulation of type I collagen in the meningeal tissue, suggesting that the meninges are a potential site for fibrosis. The time schedule of these biochemical and histological events suggest that meningeal fibrosis may be involved in the pathogenesis of late post-hemorrhagic hydrocephalus.

Evaluation of successive collections of cisternal cerebrospinal fluid in rats, rabbits, and cats ☆

Abstract The occurrence of blood contamination in cerebrospinal fluid samples obtained by percutaneous cisternal puncture, and the reproducibility of this collection method were studied in anesthetized rats, rabbits, and cats. In all species, the collection procedure was easily reproducible, and in less than one-third of the samples the erythrocyte count exceeded 2000 × 10 3 /ml. When the cerebrospinal fluid samples with erythrocyte count up to 10,000 × 10 3 /ml were included, the erythrocyte count correlated well to the protein concentration in specimens, thus reflecting the contamination degree of samples also by plasma constituents. Therefore, the purity of each cerebrospinal fluid sample obtained by the percutaneous cisternal puncture should be controlled when cerebrospinal fluid constituents with high blood to cerebrospinal fluid ratio are measured.

Transient increase in procollagen propeptides in the CSF after subarachnoid hemorrhage

Background: Meningeal fibrosis following subarachnoid hemorrhage (SAH) has been verified histologically in experimental animals and in human autopsy samples, but the clinical course of the intrathecal fibroproliferative reaction is unknown. The authors therefore studied time-related changes in the CSF concentrations of type I (PICP) and type III (PIIINP) procollagen propeptides in patients with recent SAH. Method:— Fifty-two CSF samples were obtained from 39 patients with SAH treated surgically and eight samples from eight patients with SAH who were not surgically treated. The samples were analyzed for PICP and PIIINP by using radioimmunoassays. Results: The authors found a time-dependent increase in PICP and PIIINP in the CSF of the patients with SAH. Two weeks after the hemorrhage, concentrations were four times higher in patients with SAH than the concentrations in the control subjects. Concentrations in patients with SAH then declined steadily, but remained slightly but significantly elevated even at 10 weeks. PICP and PIIINP did not correlate with the age or sex of the patient or the amount of blood in the initial CT scan. Four patients developed late posthemorrhagic hydrocephalus; their PICP and PIIINP levels were higher than in matched patients with SAH without hydrocephalus. Conclusions: Time-dependent changes in CSF concentrations of PICP and PIIINP suggest a transient fibroproliferative reaction in the meninges after SAH. The considerable magnitude and extended time course of the changes make the measurement of PICP and PIIINP practicable for the diagnosis of a fibroproliferative state in patients with recent meningeal disease. Furthermore, the results suggest a role for meningeal fibrosis in the development of late posthemorrhagic hydrocephalus.

Shunting procedures in the management of intracranial cerebrospinal fluid cysts in infancy and childhood

SummaryWidely diverging opinions on the optimal therapy for intracranial cerebrospinal fluid cysts (CSF), mainly arachnoid cysts and the Dandy-Walker cysts, exist. Excision of the cyst walls in the treatment of the Dandy-Walker cyst has been replaced by shunting procedures, but the recommended method for primary treatment of arachnoid cysts in childhood is still cyst wall excision. Membrane excision is, however, often complicated by recurrence, subsequently requiring shunting-procedures. In a series of 19 cases primary shunting of intracranial CSF cysts proved to be a reliable method. In those cases where hydrocephalus (ventricular dilatation) is present at the time of the primary operation the ventricles should be shunted as well as the cyst. The catheter from the ventricle and that from the cyst should be connected to the same valve, otherwise an increased risk of intracranial herniation exists. The prognosis for infants and children suffering from intracranial CSF cysts is in general good; in 17 out of 19 cases mental development was normal and in 15 out of 19 motor development was normal. The risk of permanent motor damage seems to be particularly high when an arachnoid cyst is located on the quadrigeminal plate.

Rapid Induction of Meningeal Collagen Synthesis in the Cerebral Cisternal and Ventricular Compartments after Subarachnoid Hemorrhage

Summary.Procollagen propeptides in the lumbar CSF increase after subarachnoid hemorrhage (SAH), and elevated concentrations have been detected as early as on day 8. We studied here the timing and localization of the induction of meningeal collagen synthesis during the first week after SAH by analysing cisternal and ventricular CSF samples. We obtained 29 cisternal and 10 ventricular CSF samples at operation from patients with SAH between days 1 and 9 after onset. The carboxyterminal propeptide of type I procollagen (PICP) and the aminoterminal propeptide of type III procollagen (PIIINP) were measured using radio-immunoassays. The concentrations of PICP and PIIINP in the cisternal CSF were elevated as early as on day 2 after SAH. PICP increased in a sigmoidal fashion (R2=0.39, p<0.001), while PIIINP increased linearly (R2=0.28, p=0.003) and was approximately 3-fold higher on day 9 than initially. PICP was twice as high (p=0.02) in the cisternal than in the ventricular CSF after SAH and PIIINP was 4-times higher (p=0.007). Interestingly, the concentrations were similar in a patient with intraventricular bleeding. The cisternal compartment contributed to the propeptides in the CSF more than did the ventricular compartment, but the latter also appeared to have a definite potential for fibroproliferative reaction. Meningeal collagen synthesis was induced rapidly within the first few days after SAH suggesting that therapeutic attempts to inhibit the fibroproliferative reaction should be started as early as possible.