Gian Franco Rossi

Surgical indications in normotensive hydrocephalus. A retrospective analysis of the relations of some diagnostic findings to the results of surgical treatment

SummaryTwenty two of fifty five patients initially suspected of suffering from normotensive hydrocephalus were surgically treated (CSF ventriculoatrial shunt). The results of surgery were related to the findings of the different diagnostic examinations (pneumoencephalography, isotope cisternography, transfer from CSF to blood of isotope labelled serum albumin, constant infusion manometric test, long lasting intraventricular pressure recording).1.Pneumoencephalography, intraventricular pressure recording, and, above all, isotope cisternography provided the most reliable data for diagnosis and surgical prognosis.2.The combined use of pneumoencephalography and isotope cisternography was sufficient for a correct diagnosis and surgical prognosis in about 50% of the patients examined.3.When the diagnostic information given by the combined results of the two above examinations was not sufficient, intraventricular pressure recording proved to be the most useful examination to supplement it.4.The relation of the results of the study of transfer of isotope labelled serum albumin from CSF to blood and of the constant infusion manometric test to the surgical outcome was uncertain.

Anatomo-clinical correlations in normotensive hydrocephalus. Reports on three cases.

The brains of 3 adult subjects suffering from normotensive hydrocephalus have been examined pathologically. The diagnosis of normotensive hydrocephalus was based on clinical symptoms, pneumoencephalography and isotope cisternography, in 1 case integrated with the results of the constant-infusion manometric test. Part of the neuropathological findings were common to the 3 patients: leptomeningeal non-obstructive fibrosis, ventricular ependymal disruption, subependymal glial reaction, periventricular demyelination and spongiosis. Other neuropathological abnormalities were peculiar to each patient: leptomeningeal signs of previous subarachnoid haemorrhage; arteriosclerosis and multiple brain cystic infarcts; Alzheimers plaques in the gray matter. The possible pathogenetic significance of the neuropathological findings summarized above in relation to the development of normotensive hydrocephalus is discussed.

An Experimental Study of the Structures Mediating Bilateral Synchrony of Epileptic Discharges of Cortical Origin

In acute experiments performed in cats under ethyl urethane anaesthesia, bilateral epileptic foci were created on the sigmoid gyri of both cerebral hemispheres. Confirming previous observations, the 2 foci were found to discharge synchronously. Bilateral synchronization was present as well between the epileptic discharges propagated to the intralaminar thalamic nuclei and midbrain reticular formation. Splitting of the corpus callosum and hippocampal commissure disrupted bilateral synchrony of epileptic discharges. The latter could be restored by increasing the intensity of epileptic activity. Additional split of the diencephalon (anterior commissure, massa intermedia and hypothalamus) again disrupted epileptic bilateral synchrony. The latter could still reappear following further increase of epileptic activity. Finally, split of midbrain tectum and tegmentum eradicated bilateral synchrony of epileptic potentials.

Spinal cord stimulation affects the central mechanisms of regulation of heart rate.

The effect of spinal cord stimulation (SCS) on heart rate (HR) was studied in 25 patients without cardiological symptoms, who were undergoing SCS for various reasons. HR at rest significantly decreased during SCS. Physiological and pharmacological maneuvers of sympathetic and parasympathetic activation or blockade before and during SCS indicate that SCS interferes with the central mechanisms of regulation of HR mainly by inducing a functional sympathectomy, and that such an effect is mediated by an action on spinal cord ascending fibers.

Interstitial brachytherapy for low-grade cerebral gliomas: analysis of results in a series of 36 cases.

SummaryThe results obtained with interstitial brachytherapy in thirty-six low-grade cerebral gliomas (2 pilocytic astrocytomas, 23 astrocytomas and 11 oligodendrogliomas) are reported (mean follow-up: 75 months, range 37–159). All tumours were situated in locations which did not call for surgical removal as the treatment of choice. Their volume ranged from 4 to 82 cc (m=32); the Karnofsky performance status (KPS) of the treated patients lay between 0.60 and 0.90.The sources utilized (Iridium-192 in 32 cases and Iodine-125 in 4) were implanted permanently in 22 patients and temporarily in 14, using the Talairach stereotactic apparatus. The mean peripheral dose was 89.7 Gy for the permanent implants and and 42.8 Gy with a rate of 32.05 cGy/h for the temporary implants. External beam irradiation was added for tumour volumes greater than 35 cc (19 cases) on a second target volume extending 2 cm beyond the tumoural borders treated with interstitial irradiation.The survival estimates for the entire group showed a probability of 82.9% at 60 months, of 56.8% at 96, 39.4% at 120 (m.s.t.: 112 months). The quality of life in the treated patients was satisfactory, KPS never falling below a mean score of 0.70. The extent of the target volume turned out to be the most significant factor influencing survival at the multivariate analysis. Severe neurological impairment due to radionecrosis occurred in 4 patients (11%), three of them requiring surgical decompression. Target volume and radiation dose showed a direct correlation with the risk of radionecrosis at the regression analysis, the critical values being 35 cc and 100 Gy (permanent implants) or 50 Gy (42 cGy/h, temporary implants) respectively. The analysis of the results indicates that, even though many questions still remain open, brachytherapy can represent a valid alternative to surgery for tumours not suitable for surgical removal.

BONE METASTASIS ASSOCIATED WITH SHUNT-RELATED PERITONEAL DEPOSITS FROM A PINEAL GERMINOMA : CASE REPORT AND REVIEW OF THE LITERATURE

SummaryThe case of a 15-year-old boy with a pineal germinoma is reported. The patient first underwent a ventriculoperitoneal (VP) shunt followed by a stereotactic biopsy, then, because of the rapidly deteriorating neurological status, an emergency craniotomy with subtotal removal of the tumour was performed. Two months after surgery, a left femoral metastasis and extensive peritoneal lesions became evident; they were regarded as due to haematogenous and VP shunt spread of the germinoma. At that time, extremely high serum levels of placental alkaline phosphatase were detected. The patient died 6 months after the inital diagnosis. The occurrence of extraneural metastases as well as of shunt related peritoneal deposits from primary intracranial germinoma is discussed. As far as we know this is the first reported case of a combination of haematogenous as well as VP shunt spread of a pineal germinoma.

Factors of surgical outcome in tumoural epilepsy.

Summary Objectives. The purposes of the study were the assessment of the role of surgery in the suppression of epilepsy due to low-grade primitive cerebral tumours and the search for factors relevant to the surgical outcome. Patients and Methods. Forty-eight patients with epilepsy due to low-grade supratentorial cerebral tumours were considered. They presented drug-resistant daily to monthly seizures since for least one year (mean 7 yrs). Twenty-four patients underwent a combined tumour and epileptogenic zone resection (“epilepsy surgery”) and 24 tumour resection alone (“lesionectomy”). The surgical outcome was evaluated two years after surgery. Several variables related to the characteristics of the epilepsy, the tumour and surgery, were considered for a possible association with the outcome. Statistical analyses were performed. Results. Seizure freedom, including aura, was obtained in 35 patients (72.9%). Mild permanent complications occurred in 6 cases. Seizure suppression was significantly associated with complete tumour resection (post-surgical CT or MRI) and relatively low presurgical seizure frequency; it was also related, though not significantly, to small tumour size and histological grade I. The surgical outcome was only slightly better following “epilepsy surgery” than “lesionectomy”. However: i) the extent of tumour resection was not relevant regarding the “epilepsy surgery” outcome, while significantly influencing the outcome after “lesionectomy”; ii) the presurgical frequency of seizures and, to a less extent, the tumour size, had a higher influence on the outcome after “lesionectomy”. Conclusion. Long-lasting and drug-resistant epilepsy due to cerebral tumours can be suppressed surgically in the majority of cases. The extent of tumour resection and the frequency of the seizures are the most relevant prognostic factors. Both “epilepsy surgery” and “lesionectomy” can provide good results. However, the two approaches should not be regarded as interchangeable: a choice of the approach based on the characteristics of seizures and of the tumour appears relevant to improve the surgical prognosis.

Resection surgery for partial epilepsy. Relation of surgical outcome with some aspects of the epileptogenic process and surgical approach

SummaryIn spite of the progressive improvement of the results of resective surgery for epilepsy, the number of not significantly benefited patients remains high. An attempt was made to find out a relation between outcome and some aspects of the pathophysiological organization of the epileptogenic process and of the surgical procedure. Chi-square and logistic regression statistic analyses were utilized. The study was retrospectively performed on 138 surgically treated patients having a minimum follow-up of three years. Three classes of surgical outcome were considered: completely seizure free (including aura; 86 cases, 62.3%), significant seizure reduction (31 cases, 22.5%), and no significant improvement (21 cases, 15.2%). What follows was brought into evidence by the study. 1) On the diagnostic side, the spatial arrangement (focal, unilateral, multifocal) of both the interictal and the ictal epileptic electrocerebral activities are significantly associated with the surgical outcome. Their relative impact on outcome is related to the presence of a structural lesion: when a lesion is documented, the interictal activity has the higher value; vice versa, when no lesion is apparent, the role of the ictal activity is prevalent. However, the presence, as well as the nature of the lesion, per se, are not significantly associated with outcome. 2) On the surgical side, the extent of resection of both the structural lesion and of the epileptogenic zone are highly associated with the surgical result; the extent of lesion resection prevails on that of the epileptogenic zone. The type of surgical approach (hemispherectomy: 17 cases; temporal lobectomy: 67 cases; extratemporal resection: 54 cases) has no significant relation to the outcome. The value and the limits of the results obtained are discussed.

Epidural spinal cord stimulation for the treatment of neurogenic bladder

SummaryThe effect of percutaneous epidural spinal cord stimulation on neurogenic bladder has been evaluated on the basis of objective clinical and urodynamic criteria. Seven patients suffering from stable bladder and sphincter dysfunction due to spinal cord diseases of different causes of non-evolutive nature were examined. In some of them chronic pain or spasticity, or both, were also present.Spinal cord stimulation substantially improved micturition in six out of seven patients. Complete or almost complete relief of bladder spasticity, marked increase of bladder capacity, and reduction or abolition of residual urine were recorded. The beneficial effect on bladder and sphincter function is strictly dependent on the stimulation, though it can outlast it. It requires some weeks to reach its maximum. It is still obtained after 22 months of treatment (longest present follow-up).No changes of striatal activity and detrusor reflex were produced by spinal cord stimulation in two additional patients, treated for chronic pain but having intact bladder function.

Interaction of epileptic activities of bilateral deep temporal origin. An experimental study.

The interaction of epileptic activities obtained with electrical or chemical (penicillin) stimulation of the amygdaloid nuclear complexes of the two sides was studied in acute experiments on the rabbit. Several findings indicate that reciprocal influences between the two epileptogenic amygdalae can occur. Inhibitory as well as facilitatory interactive phenomena were observed. The occurrence of interaction and its sign seem related to the level of epileptic activity.