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Biomedical subjects

G F Rossi

Publications and source records attributed to G F Rossi.

At least 19 recordsLinked to original sources

Factors of surgical outcome in tumoural epilepsy.

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.

Adolescent↗

Intraoperative motor evoked potentials monitoring in spinal neurosurgery.

Neurological damage may follow even a technically accurate spinal surgery. The intraoperative monitoring of neurological functions put at risk by the operation is a method utilized to correctly identify the topography of neural structures and to avoid surgical insults. SEPs monitoring is 20 year old, and only recently direct motor tract monitoring has become possible. Transcranial electrical motor cortex stimulation with single pulses or with short trains of stimuli and recording of the evoked responses from the spinal epidural space (D-waves) and from limb muscles is a reliable and safe technique for monitoring corticospinal tract activity even under general anesthesia. The method has a solid theoretical experimental background. Its clinical application has demonstrated high sensitivity and specificity. Intraoperative MEPs monitoring is nowadays considered indispensable during spinal neurosurgery.

Animals↗

[Physiopathology of non-traumatic subarachnoid hemorrhage: loss of consciousness].

The mechanisms underlying the loss of consciousness following the SAH can be only hypothesized at present time. The more convincing hypothesis appears to be the role of a cerebral circulatory insufficiency. Such an hypothesis stems from the following chain of events: 1) immediate increase of the intracranial pressure; 2) simultaneous constriction of the arteries of the poligone of Willis (early vasospasm); 3) decrease of the cerebral perfusion pressure; 4) cerebral ischemia. Different cerebral regions can be affected by the ischemia according to the prevalent location of the SAH, as for instance brain stem or telencephalon; consequently, different pathophysiological modalities can be responsible for the consciousness impairment. The entity of the SAH and of the consequent events responsible for the cerebral ischemia, influence the severity and reversibility of the loss of consciousness.

Brain Ischemia↗

Motonuclear changes after cranial nerve injury and regeneration.

Little is known about the mechanisms at play in nerve regeneration after nerve injury. Personal studies are reported regarding motonuclear changes after regeneration of injured cranial nerves, in particular of the facial and oculomotor nerves, as well as the influence that the natural molecule acetyl-L-carnitine (ALC) has on post-axotomy cranial nerve motoneuron degeneration after facial and vagus nerve lesions. Adult and newborn animal models were used. Massive motoneuron response after nerve section and reconstruction was observed in the motonuclei of all nerves studied. ALC showed to have significant neuroprotective effects on the degeneration of axotomized motoneurons. Complex quantitative, morphological and somatotopic nuclear changes occurred that sustain new hypotheses regarding the capacities of motoneurons to regenerate and the possibilities of new neuron proliferation. The particularities of such observations are described and discussed.

Acetylcarnitine↗

Callosotomy for severe epilepsies with generalized seizures: outcome and prognostic factors.

The purpose of the present study was to verify the effect of callosotomy on generalized seizures, to check the effect on other seizure types and to search for possible prognostic factors. Twenty patients with a minimum follow-up of one year (mean 3.5 years) were available for our analysis. In six of them the callosotomy was performed in two stages (total: 26 surgical procedures). Age ranged from 14 to 40 years (mean 23 years). Different aetiologies were known in 15 patients. Duration of epilepsy ranged from 6 to 23 years (mean 15 years). The frequency of seizures ranged between 19 and 750 per month. The most significant effect of surgery was the complete suppression of the generalized seizures associated with falling in 9/19 and their reduction of more than 80% in 7/19 patients (total "good results": 16/19). The generalized tonic-clonic seizures were less affected. The surgical effect on the partial seizures was very variable, the partial simple seizures being the most affected. A positive statistical association with the outcome of the generalized seizures with fall was found for a presurgical seizure frequency below 90 per month, a prevalent bilateral EEG epileptic activity and, to a less extent, the absence of cerebral structural lesions. The role of age, aetiology, duration of the disease, single or more seizure types, mental impairment and extent of callosotomy remains uncertain. Disconnection syndrome does not appear if the splenium is spared. The present findings confirm that the main indication for callosotomy is the occurrence of generalized seizures with fall. Surgery can be initially limited to the anterior 2/3 of the corpus callosum; further posterior section of the corpus, excluding the splenium, should be regarded as a second step, when necessary.

Adolescent↗

Prognostic factors in low grade (WHO grade II) gliomas of the cerebral hemispheres: the role of surgery.

OBJECTIVE: To assess the role of surgery on survival of patients with grade II gliomas of the cerebral hemispheres. METHODS: One hundred and thirty one low grade hemispheric gliomas surgically treated (biopsied patients excluded) between 1978 and 1989 were retrospectively reviewed. Thalamic, basal ganglia, callosal, or ventricular location were not considered. All tumours were World Health Organisation (WHO) grade II gliomas: 42 fibrillary and 11 gemistocytic astrocytomas, 49 oligodendrogliomas, and 29 oligoastrocytomas. Patients' ages ranged from 14 to 63 (mean 32.9, median 34) years, Karnofsky performance from 0.50 to 0.90 (mean 80.7, median 80), and postsurgical follow up of the living patients from 24 to 190 (mean 97.02, median 93) months. Postoperative external radiotherapy was performed in 49 cases. RESULTS: The overall survival probability at five years was 97.1%, at eight years 76.1%, and at 10 years 62.7% (median survival time 144 months). The impact on survival of the following variables was analysed: age (< 20, 21-40, and > 40 years), Karnofsky score (80-100, 70 < or = 70), histology, tumour extension (T1 < 3 cm, T2 3-5 cm, T3 > 5 cm maximum diameter), extent of surgical resection (S1 radical, S2 subtotal < 10% residual tumour, S3 partial-10%-50% residual tumour), and radiotherapy (either performed or not). A significant positive association with survival at univariate analysis was found for the age group < 20 years (P = 0.003), for total and subtotal surgical resections (S1 and S2; P < 0.001) and for the non-irradiated patients (P = 0.0049), whereas a shorter survival probability was noticed for gemistocytic astrocytomas (P < 0.001) and for tumour extension > 5 cm (T3; P = 0.0193). Karnofsky performance did not show any significant association with survival. The most relevant factor affecting survival at the multivariate analysis was the extent of surgical resection, which resulted as the only variable retaining a significant value (P = 0.001, risk factor = 2.20). CONCLUSIONS: The data strongly support the role of a surgical removal as extensive as possible in the treatment of these tumours.

Adolescent↗

Superior cervical ganglion regenerating axons through peripheral nerve grafts and reversal of behavioral deficits in hemiparkinsonian rats.

The superior cervical ganglion (SCG) has been grafted to the brain of adult rats in an attempt to reverse the parkinsonian syndrome that follows destruction of central dopamine systems. However, the main limitation to this approach is the massive cell death that occurs in the grafted SCG after direct transplantation into the brain. In adult rats, 6-hydroxydopamine (6-OHDA) was stereotactically injected into the right substantia nigra (SN). One month later, dopamine denervation was assessed using the apomorphine-induced rotational test. In rats with a positive test, an autologous peripheral nerve (PN) graft was tunneled from the right cervical region to the ipsilateral parietal cortex. One end of PN graft was sutured to the transected postganglionic branch of the SCG and the other end was inserted into a surgically created cortical cavity. The apomorphine test was repeated at 3 days and again at 1, 3, and 5 months after surgery. The brain, SCG, and PN graft were studied under light and electron microscopy and with the tyrosine hydroxylase immunohistochemical and horseradish peroxidase tracing methods. Three days after grafting, there were no significant differences on the apomorphine test as compared to the preoperative test. Conversely, 1,3, and 5 months after grafting, the number of rotations was reduced by 69% (+/-20.2), 66.6% (+/-17.1), and 72.5% (+/-11.3), respectively. Control rats that received a free PN graft to the brain and underwent section of the postganglionic branch of the SCG did not show significant changes on the apomorphine test after surgery. Histological examination revealed that the PN graft was mostly reinnervated by amyelinic axons of small caliber. Approximately 40% of the SCG neuronal population that normally projects to the postganglionic branch survived axotomy and regenerated the transected axons into the PN graft. Axons arising from the SCG elongated the whole length of the graft, crossed the graft-brain interface and extended into brain regions adjacent to the denervated striatum up to 2037 micrometer from the graft insertion site. This work shows that the ingrowth of catecholamine-regenerating axons from the SCG to dopamine-depleted brain parenchyma significantly reduces behavioral abnormalities in hemiparkinsonian rats. This effect cannot be ascribed either to the brain cavitation or to the PN tissue placement in the brain.

Animals↗

Surgical treatment of clival chordomas: the transsphenoidal approach revisited.

This is a report of 12 cases of clival chordomas that were surgically treated at the Catholic University Medical School, Rome, Italy, over a 7-year period. The study emphasizes the role of the transsphenoidal approach. The study group included seven men and five women whose ages ranged from 26 to 80 years (mean 49.8 years). Diplopia was the most common presenting symptom (eight cases). The tumor involved the upper and middle clivus in five cases, the middle clivus in five, and the lower clivus in two cases. One patient developed spinal metastasis. On histological examination, eight cases proved to be typical chordomas, three cases had a chondroid component, and one case of chordoma had atypical features. Immunohistological staining for vimentin and epithelial membrane antigen was positive in all cases. Follow-up periods ranged from 14 to 86 months (mean 40.2 months). The primary treatment consisted of surgery. Ten patients with chordomas of the upper and middle clivus underwent a total of 13 transsphenoidal procedures. Total tumor removal was achieved in seven cases, subtotal removal in two, and partial removal in one case. In the two cases of lower clival chordomas, total removal was accomplished in one and partial removal in the other. After total removal, no recurrence was noted at 14 to 86 months (mean 37.5 months). In the cases undergoing operation via a transsphenoidal approach, there was zero morbidity and one cerebrospinal fluid fistula that resolved without surgery. The tumor recurred in two patients after subtotal and partial removal, respectively. The authors opted to reoperate in cases of recurrence. Postoperative radiotherapy was administered in only two cases in which further surgery was not indicated because of medical reasons or because such a procedure was contrary to the patient's wishes. When mortality and morbidity rates of this group are compared to those of chordoma patients who were treated with extensive skull-base surgery, the results prompt a reappraisal of the transsphenoidal approach in the treatment of clival chordomas.

Adult↗

Callosotomy for intractable epilepsy from bihemispheric cortical dysplasias.

Four patients suffering for severe drug-resistant epilepsy from bihemispheric cortical dysplasias underwent anterior callosotomy. One of these patients also presented mental retardation of mild degree associated with the epileptic syndrome. There were no operative complications in this series. Clinical signs of interhemispheric disconnection were not detectable postoperatively. Twenty-eight to 53 months after surgery, the generalized seizures were completely suppressed in 2 cases, and were reduced by 89-97% in frequency in the other 2 cases. Partial seizures were less affected by callosotomy being reduced by 14-87%. In an additional fifth case of intractable epilepsy from bihemispheric cortical dysplasias with associated severe mental retardation operated upon elsewhere for callosotomy and followed at our institution, the outcome for seizures was completely unsatisfactory. Neurophysiological studies revealed that the interhemispheric transfer (IHT) of visuo-motor responses was functionally impaired after callosotomy only in one patient who harboured bilateral cortical dysplasias in the occipital lobes. This malformation might affect the pattern of axonal projection to the posterior portion of the corpus callosum which is considered of crucial importance for the integration of crossed visuo-motor responses. From this paper the following conclusions can be drawn: a) epileptic patients with severe drug-resistant epilepsy due to bihemispheric cortical dysplasias are good candidates for callosotomy, b) one-stage extensive anterior callosotomy sparing the splenium is the procedure of choice, c) associated severe mental retardation seems to contra-indicate callosotomy, d) the neurophysiological study of the IHT can yield information on the functional status of the corpus callosum.

Adult↗

Surgical treatment of craniopharyngiomas: an evaluation of the transsphenoidal and pterional approaches.

Fifty-seven patients with craniopharyngiomas underwent a total of 64 operations. Their clinical follow-up ranged from 2.5 to 15.5 years, with a mean follow-up of 6.5 years. A transsphenoidal approach was used in 35 patients (61%), whereas 22 (39%) were operated on using a pterional approach (in 16 patients, the tumor was found in the suprasellar cisterns, and in 6, the tumor was found in the third ventricle and was removed passing through the lamina terminalis). Total removal of the tumor was achieved in 43 patients (75%). In six patients (11%), fragments of the capsule remained attached to the hypothalamus (subtotal removal), and, in eight patients (14%), the tumor was partially removed. No recurrence occurred in those patients in whom removal was total. Regrowth was observed in two patients (33%) in whom removal was subtotal and in two (25%) in whom removal was partial. Three of them underwent subsequent operations, and a total removal with good clinical outcome was achieved. All patients except two had good postoperative recovery. Twenty patients (35%) required hormonal replacement therapy. When transsphenoidal surgery was used, a total removal of the tumors was achieved in 23 (66%) of the patients. Good clinical outcome was seen in all 35 patients. Six patients (17%) required hormonal replacement therapy. When the pterional approach was used for tumors in the suprasellar cisterns, we achieved total removal of tumors in 15 patients (94%). Good clinical outcome was seen in 20 patients (91%). Eleven patients (50%) required hormonal replacement therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Interhemispheric integration of simple visuomotor responses in patients with partial callosal defects.

Because of the organization of visual and motor pathways, simple manual responses to a light stimulus in the right or left visual hemifields are performed faster with uncrossed hand-field combinations than with crossed hand-field combinations. Uncrossed responses can be integrated within a single hemisphere, whereas crossed responses require a time-consuming interhemispheric transfer via the corpus callosum which is reflected in the difference between crossed and uncrossed reaction times. We investigated crossed-uncrossed differences (CUDs) in speed of simple visuomotor responses to lateralized flashes in seven subjects with an anterior section of the corpus callosum sparing the splenium and in one subject with an agenetic absence of the splenium due to a cerebrovascular malformation. There was no evidence of an abnormal prolongation of the CUDs in any of these subjects, in sharp contrast with the very long CUDs exhibited by an epileptic subject with a complete callosal section and two subjects with total callosal agenesis tested in the same experimental situation [1]. The normality of the CUDs in the subjects with partial callosal defects was not due to a postoperatory reorganization of interhemispheric communication, since there was no indication of an increased CUD in a patient tested as early as 5 days after the anterior callosotomy. These results are compatible with the assumption that both anterior and posterior callosal routes may subserve the integration of speeded manual responses to a visual stimulus directed to the hemisphere ipsilateral to the responding hand.

Adult↗

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

The 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.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

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

In 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.

Adolescent↗

[Surgical treatment of epileptogenic hemimegalencephaly].

Thirteen children affected by hemimegalencephaly were observed in the Pediatric Section of the Institute of Neurosurgery of the Catholic University of Rome in the last six years. Nine of them were operated because of an intractable epilepsy. Seven were males and 2 females; the age at operation ranged between 7 months and 11 years (mean: three years and five months); the follow-up period varied between 1 and 6 years (mean 3 years and 10 months). All the patients had a clinical history of daily epileptic seizures not responsive to medical treatment; all of them presented with severely delayed psychomotor development. At neurological examination, six children showed a motor deficit of variable severity contralateral to the affected hemisphere and two patients a severe tetraparesis. The remaining child did not present with motor deficit. In all the cases the diagnosis had been obtained by CT scan and MRI. One of the cerebral hemispheres was abnormally enlarged with associated dilation of the lateral cerebral ventricle. The cortical architecture was obviously deranged with several areas of heterotopia of the gray substance suggesting an alteration of the neuronal cell migration. All the children underwent an extrathalamocaudato hemispherectomy. A post-operative ventriculo-peritoneal shunt was required in two cases. There were neither operative, nor late deaths. A dramatic reduction in the frequency and severity of epileptic seizures was observed in all but one of the patients of the series.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗

Staging of supratentorial hemispheric glioma using tumour extension, histopathological grade and extent of surgical resection.

A 'TGS' classification for supratentorial brain glioma is proposed, based on three parameters: tumour extension (T), histopathological grade (G) and extent of surgical resection (S). Two groups of patients were analysed: the first (n = 137) had tumour submitted to stereotactic biopsy; the second (n = 60) had malignant glioma operated on by craniotomy and tumor resection. All three staging parameters significantly influenced survival. Histopathological grade was the most significant factor, and the only independent variable on multivariate analysis, followed by extent of tumour and then extent of surgical resection. The data support the applicability of the proposed parameters for a staging classification of hemispheric brain glioma.

Adolescent↗

Interstitial irradiation for newly diagnosed or recurrent malignant gliomas: preliminary results.

The preliminary results obtained in 19 patients treated with interstitial irradiation for malignant gliomas are reported. Three different groups are included in the study: I Newly diagnosed tumours not suitable for surgery: 13 cases (10 anaplastic astrocytomas (AA) and 3 glioblastomas (GBM), mean volume 46.56 cc, source Ir 192) were implanted permanently (n = 11, mean peripheral dose 93.54 Gy) or temporarily (n = 2, 50 Gy = 0.5 Gy/hr). External beam irradiation was additionally applied in all cases. II Residual or recurrent tumours: 5 patients (2 AA and 3 GBM, mean volume 7.2 cc, source Ir 192) received temporary implants (150 Gy peripheral dose = 1.5 Gy/hr) after surgery and conventional radiotherapy. III Newly diagnosed surgically removable tumours: only one patient with AA (15 cc volume, source Ir 192) received temporary implantation with the same dose regimen used in Group II before surgery and external beam irradiation. A median survival time of 26.75 mos (34.62 mos for AA, with 3 long-term survivors) was observed in the patients of Group I. Three patients of Group II are still alive after 8, 12 and 12 mos after brachytherapy, the other 2 (GBM) survived 7 and 12 mos. The single patient so far included in Group III is still alive after 6 mos. Although the study is still in progress, these preliminary data seem to indicate that interstitial radiotherapy can be effective in prolonging survival of patients with malignant gliomas.

Adult↗

Hemispheric control of unilateral and bilateral responses to lateralized light stimuli after callosotomy and in callosal agenesis.

Normally, simple digital or manual responses to a light stimulus in the right or left visual hemifields are performed faster with uncrossed hand-field combinations than with crossed hand-field combinations. Because of the organization of visual and motor pathways, the integration of uncrossed responses is assumed to occur within a single hemisphere, whereas a time-consuming interhemispheric transfer via the corpus callosum is considered to be necessary for the integration of crossed responses. However, callosal transfer may be dispensable for those crossed responses which can be controlled through ipsilaterally descending motor pathways by the hemisphere receiving the visual stimulus. We investigated crossed-uncrossed differences (CUDs) in speed of simple visuomotor responses to lateralized flashes in one subject with total section of the corpus callosum and two subjects with complete callosal agenesis. We recorded the reaction times as well as the premotor times, as indicated by the electromyographic latencies of the prime movers, of three types of responses: a distal response involving a thumb flexion, a proximal response chiefly involving a forearm flexion and an axial response involving a shoulder elevation. Further, the three types of responses to a single lateralised flash were performed both unilaterally and bilaterally. The three acallosal subjects showed CUDs greatly exceeding normal values on distal responses, either unilateral or bilateral, and on unilateral proximal responses. These abnormally long CUDs stood in sharp contrast to the insignificant CUDs exhibited by the same subjects on bilateral proximal responses and on unilateral and bilateral axial responses in agreement with correspondingly insignificant CUDs reported for normal subjects. These results confirm that a callosal contribution is important for the execution of fast distal and unilateral proximal responses to a visual stimulus directed to the hemisphere ipsilateral to the responding hand. By contrast, the other types of crossed responses appear to be efficiently coordinated across the midline without the aid of the corpus callosum. This is in keeping with the hypothesis that they are governed by a bilaterally distributed motor system which is preferentially activated for the execution of symmetrical bilateral movements, employing axial and proximal limb muscles.

Accidents, Traffic↗