Divided visuo-spatial attention systems with total and anterior callosotomy.

The role of the corpus callosum in the inter-hemispheric integration of the visuo-spatial attention system, was investigated in patients with a total callosotomy or with an anterior callosal section. Subjects produced simple reaction times (RTs) to visual targets shown to the left or right visual hemifield. Preceding the target by an interval of 500 ms, arrow cues predicting the target location were shown left and right of the point of ocular fixation. For a majority of total and anterior callosotomy patients, results with valid focused cues (both arrows pointing to the target location) and with divided-attention cues (arrows pointing away from fixation) did not differ and both conditions produced shorter RTs than with neutral cues (equal signs). In contrast, neurologically intact subjects showed equal RTs with divided-attention and neutral cues, whereas valid focused cues produced reduced RTs relative to neutral cues. These results indicate that most split-brains, in contrast to normal observers, are capable of directing their attention to left and right visual field locations simultaneously, and therefore that each cerebral hemisphere controls its own visuo-spatial attention mechanism.

Callosal and cortical contribution to procedural learning.

Acallosal and callosotomized subjects usually show impairments on tasks requiring bilateral interdependent motor control. However, few studies have assessed the ability of these subjects to learn a skill that requires the simultaneous contribution of each hemisphere in its acquisition. The present study examined whether acallosal and callosotomized subjects could learn a visuomotor skill that involved a motor control from either both or a single hemisphere. Eleven adult patients, six acallosal and five callosotomized, participated in this study. Seven of these patients had epileptic foci located in the frontal and/or temporal areas and one of the acallosal patients showed bilateral prefrontal atrophy following surgical removal of an orbitofrontal cyst. The performance of the experimental subjects was compared with that of 11 matched control subjects, on a modified version of a serial reaction time task developed by Nissen and Bullemer (Cogn Psychol 1987; 19: 1-32). This skill acquisition task involved bimanual or unimanual key-pressing responses to a sequence of 10 visual stimuli that was repeated 160 times. A declarative memory task was then performed to assess explicit knowledge of the sequence. None of the experimental subjects learned the task in the bimanual condition. Patients with frontal epileptic foci or orbitofrontal damage also failed to learn the task in the unimanual condition when they were using the hand contralateral to the damaged hemisphere. All other subjects, including the acallosal and callosotomized patients with temporal foci, learned the visuomotor skill as well as their controls in the unimanual condition. In spite of the absence of transfer and interhemispheric integration of procedural learning, some of the acallosal and callosotomized patients were able to learn the sequence explicitly. These findings indicate that the corpus callosum and the frontal cortical areas are important for procedural learning of a visuomotor skill. They also confirm the dissociation described by Squire (Science 1986; 232: 1612-9 and J Cogn Neurosci 1992; 4: 232-43) between the declarative and procedural memory systems and extend this dissociation to processes involving simultaneous bihemispheric co-operation.

Tuberculous spondylitis: a retrospective study on a series of 12 patients operated on in a 25-year period.

BACKGROUND: The incidence of tuberculous spondylitis, which had declined steadily for over 40 years in our countries, started increasing again in the eighties, paralleling the resurgence of pulmonary tuberculosis. Therefore it has become a matter of discussion in contemporary literature, because it can be a diagnostic challenge and, in spite of its severe neurological complications, it is a potentially curable illness. METHODS: In this retrospective study the authors report their experience concerning 12 patients operated on in a 25-year period because of serious cord compression from thoracic (9 cases) and cervical (1 case) tuberculous spondylitis or from thoracic tubercular epidural lesion (2 cases). Surgical techniques were selected on the basis of the cause of cord compression. Fusion with autologous bone and metallic osteosynthesis was performed in the cervical case (1986); no other patient received spinal instrumentation, and this can be explained with the consideration that all but one cases of Pott's paraplegia were treated in the years 1968-1977. In all of these cases fusion was achieved by means of plaster jackets and prolonged bed rest. Prolonged chemotherapy was systematically administered. RESULTS: Follow-up data collected in 1995 show good and long-lasting results. CONCLUSIONS: They conclude that surgical treatment is required in case of cord compression and results can be excellent even in presence of severe neurological impairment; spinal instrumentation available in our era should be now considered in order to make rehabilitation earlier and morphologic results more satisfactory.

The role of corpus callosum in experimental epileptogenesis. A brief survey of literature.

The authors briefly summarize the experimental papers dealing with the role of corpus callosum in experimental epileptogenesis published over more than half a century. On the whole, the experimental work concerns more electro-encephalographic findings than epileptic manifestations in animals. The papers taken into account are classified in two main groups: I) positive findings supporting the efficacy of callosotomy in preventing generalization of initially localized seizures. II) papers failing to demonstrate any positive effect of commissurotomy on the generalization of discharges. On these grounds, experimental studies lack of homogeneity and cannot constitute a reliable basis for making surgical decision in clinical practice. However some remarks of practical use can be derived: a) the usefulness of the corpus callosum division for the management of secondarily generalized epilepsies appears to be sufficiently demonstrated in most studies; b) then is also evidence that the corpus callosum conveys inhibitory and/or suppressive stimuli as well, the practical value of which is still to be established; d) the corpus callosum is the most important but not the only anatomic structure for spreading seizures. Anterior and posterior commissures, thalamus, tegmentum tectum may play the same role.

Predictive factors of callosotomy in drug-resistant epileptic patients with a long follow-up.

Some possible factors to predict outcome after callosotomy were investigated in a personal series composed of 36 patients. Twenty-seven of them were submitted to anterior callosotomy, 1 to posterior callosotomy and the remaining 8 patients to two stage complete division of corpus callosum. All factors, either positive or negative, do not appear completely reliable; they can be envisaged only in relative terms and do not seem to be relevant to make surgical decision or to discard surgery. In author's series, dealing specifically with drop-attacks, it clearly appeared that abrupt falls to the ground unpreceded by other epileptic features did definitely better. This was the only statistically significant datum.

Modifications in morphology of epileptic seizures after callosotomy.

The callosotomy on drug-resistant epileptic seizures may abolish or reduce their frequency and may modified the morphology of different kind of seizures. Our series is composed of 36 patients. Drop-attacks and complex partial seizures (CP) were present in all patients, generalized tonic-clonic seizures (GTC) in 16 (44.4%) and simple partial seizures (SP) and myoclonic attacks (MY) in 6 patients each. We found two kinds of modifications: a) lateralization of hypotonia which becomes hemisomatic, with lateral bending to the hypotonic side; b) different way of falling, due not only to the lateralization of hypotonia but also to the gradual impairment of muscle tone. Modifications in CP mainly concerned automatisms, which disappeared in 39.1% of patients, while 34.8% of them had a significant reduction in automatisms; this reduction consisted in simplification of automatic movements and in shorter duration of seizures.

EEG Patterns after callosotomy.

In 36 patients with drug-resistant epilepsy submitted to anterior callosotomy (27 cases), to two-stage total callosotomy (8 cases) and to posterior callosotomy (1 case) the EEG variations concerning background activity, focal activity and sharp-waves (SW) bisynchronous activity were evaluated. EEG modifications observed after callosotomy are the following: background rhythm tends to be better organised as spectral analysis demonstrated, this finding usually coincide with reduction of bisynchronous discharges. It appears that improvement in background activity cannot be correlated with outcome, but it seems to be to some extent since at the same time cognitive functions also seem to improve; however, this last aspect need to be checked in much larger series. The number and location of EEG foci do not change, but they appear to be more active; this is likely to depend only on the concomitant reduction of bisynchronous activity. No correlation seems to exist between the number and the location of foci, which are generally multiple. Lateralization of bisynchronous discharges as well as the reduction of their frequency and duration were observed. However, the clinical course is quite different: in some patients we have achieved good clinical responses in others postoperative results were poor. Lateralization of bisynchronous discharges is never absolute, on the grounds that in prolonged recordings bisynchronous discharges are nearly always present. Bisynchronous discharges in some cases are alternatively predominant in both hemispheres even within minutes or seconds. It was observed that after certain time, generally some months, lateralized discharges tend to generalize again, confirming that corpus callosum is replaced in discharge diffusion by other structures (brain-stem, diencephalon).

Mutism in 36 patients who underwent callosotomy for drug-resistant epilepsy.

Thirty-six drug-resistant epileptic patients submitted to callosotomy were studied. Anterior callosotomy was performed in 27 patients, total two-stage callosotomy was performed in 8 patients and 1 patient had only posterior callosotomy. We found mutism in 10 patients (2 after complete callosotomy and 8 after anterior section). The patients did not speak, but the comprehension was present: they were able to carry out orders and to write. Their attitude to the environment was characterized by complete indifference. The mutism was always transient, lasting from 4 to 25 days (mean 7 days). Regression of mutism was always complete. We think that this complication should be chiefly attributed mainly to surgical manipulation, even if it is impossible to completely exclude a multi-factorial etiology.

[Chemofiltration for locally advanced cancer].

In chemofiltration a large dose of a cytotoxic drug is infused into an artery supplying a cancerous area, thus limiting systemic toxicity. The venous return from the area is pumped into a chemofiltration unit at 750 ml/min and the drug is filtered out of the blood, which is then returned to the systemic circulation. Of 22 patients with locally advanced cancer, systemic chemotherapy had failed in 63%. 9 of them underwent chemofiltration of the liver for advanced metastatic cancer of the colon (4 cases), rectum (2), breast (2) and ovaries (1); and 13 underwent chemofiltration of the pelvis for advanced cancer of the rectum (5), malignant melanoma (5), ovaries (1), cervix uteri (1) and vulva (1). The following drugs were used: 5-FU (750 mg/m2/10 min) and mitomycin-C (30 mg/m2/10 min) for colorectal, ovarian and breast carcinomas; melphelan (1 mg/kg/20 min) or cisplatinum (200 mg/m2/30 min) for malignant melanoma or ovarian carcinoma; mitomycin-C or bleomycin (50 mg/m2/10 min) for carcinoma of the cervix or vulva. 1 patient with extensive liver metastases died of respiratory failure 28 days after the procedure. Surgically related complications occurred in 16% and included wound hematoma (2 cases), infection (1) and venous thrombosis (1). Drug-related complications occurred in 50%, and included transient leukopenia (9), mild renal failure (1), hair loss (2) and prolonged paralytic ileus (1). Partial remission was observed in 10/20 patients who had measurable disease. Time to progression was 5.4 months (range: 4 weeks to 20 months). Stabilization of disease occurred in 7/20 (35%), while in 3 the disease progressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Marfan syndrome with aortic dissection and triple-barrel aorta.

A case of Marfan syndrome with spontaneously and subsequently developed dissections of the aorta, one in the form of triple-barrel aorta, three times corrected by grafts is described. The autopsy revealed "healed" and acute dissections in almost the entire aorta outside the grafts. "Healed" thoracoabdominal dissection had true lumen (with entry and re-entry intimal tears), and old false lumen and in addition in its distal portion of a triple-barrel aorta was formed (dissection of healed aortic dissection). Lethal adventitial rupture occurred in the portion with an old false lumen. Dissection of the left subclavian artery, the right common carotid artery, resulting in saccular aneurysm, and avulsion of the right renal artery were also found.

Monosialoganglioside in subarachnoid hemorrhage.

We studied 119 patients with disturbance of consciousness following subarachnoid hemorrhage, due mostly to verified aneurysm rupture, admitted to five Italian neurosurgical departments over 18 months. Level of consciousness as assessed by score on the Glasgow coma Scale ranged from 8 to 14 before the beginning of treatment; level of consciousness was assessed again 7, 14, and 21 days later. Patients were randomly allocated to treatment with monosialoganglioside or placebo according to a double-blind experimental design. The two treatment groups were homogeneous at entry with regard to the main clinical parameters. Both groups improved, but the rate and degree of improvement were greater in the monosialoganglioside-treated group. The difference was significant on days 14 (p = 0.04) and 21 (p = 0.02). Our results seem to confirm the hypothesis that monosialoganglioside reduces brain edema and provides nonspecific neuronal membrane protection.

Percutaneous twist-drill craniostomy for the treatment of chronic subdural haematoma.

A consecutive series of 65 adult patients with chronic subdural haematoma was reviewed to ascertain the efficacy of twist-drill craniostomy and closed-system catheter drainage. In all patients but two the percutaneous evacuation of the haematoma alone was enough to bring about their recovery. Infections or neurological complications were never observed. Pneumocephalus was likewise absent in all patients. Therefore this technique should be recommended as the "first intention" management of the disease, particularly in elderly patients.

Evolution of neuropsychological changes after partial callosotomy in intractable epilepsy.

Early neuropsychological changes following partial anterior callosotomy were evaluated in 15 patients with epilepsy (10 secondary generalized and 5 Lennox-Gastaut syndromes) by comparing their performances 1 month before surgery and then 15-20 and 90-100 days postoperatively without modifying the anticonvulsant treatment. The following neuropsychological and motor functions were tested: memory, attention, visuo-motor ability, posture, motor dexterity, language, praxis and gnosis. Social behaviour was also investigated. The main results are as follows: (i) most cognitive functions showed no significant variation; (ii) motor organization was still slightly impaired at the second check-up after the surgery; (iii) improvements in social behaviour and posture were frequently observed at the final evaluation. The analysis of individual cases highlights the influence of the extent of commissurotomy, lesions related to the surgical procedure and preoperative brain damage in determining the post-surgical profile. On this basis, the short-term neuropsychological cost of partial callosotomy appears to be low and seems to depend mostly on surgical parameters and brain conditions before the operation.

Callosotomy for the treatment of drug resistant generalized seizures.

Fifteen patients have been followed for more than one year following callosotomy having presented with long standing epilepsy, no well defined focus amenable to radical excision, and severely incapacitating atonic seizures that were refractory to anticonvulsant therapy. Atonic fits have been reduced by more than 80% in thirteen patients, with two patients suffering long term sequelae (slight dysarthria in one, and dyslexia with mild visuo-spatial disturbances in another). Anticonvulsant therapy was still required post-operatively.

Malignant glial tumours: prognostic value of quantitative microscopy.

Nuclear and cell density features have been measured in 22 cases of glioblastoma divided into two groups according to their survival periods, i.e. less than 12 months or more than 12. The results have demonstrated that the logarithmic transformation of the following features show up statistically significant differences (p less than 0.05): mean of the logarithm of nuclear area, standard deviation of the logarithm of perimeter and standard deviation of the logarithm of the roundness factor. The standard deviation of the roundness factor has been shown to be another parameter with statistically significant differences between the two groups. Forward stepwise discriminant analysis was adopted in order to identify the quantitative features which contributed most significantly to discriminating between the two groups. The results suggested a combination of two features, i.e. the standard deviation of the logarithm of the roundness factor and the mean of the logarithm of the roundness factor. The comparison between actual and predicted categories showed 68.18% agreement: 7 out of 22 cases were allocated incorrectly by the computer. However, when a classification probability threshold was adopted, the 7 incorrectly allocated cases assumed an "intermediate" position between the two groups, in agreement with their survival.

[Remarks on callosotomy in the treatment of drug-resistant epilepsy]. / Remarques sur la callosotomie dans le traitement de l'épilepsie pharmaco-résistante.

In this report 17 patients with long-standing non-focal epilepsy underwent callosotomy (this was total in two patients and performed in two stages, and anterior-subtotal in the remaining patients). In all patients the atonic-hypertonic seizures with sudden falls were the most disabling epileptic fits. Callosotomy proved efficient in controlling atonic fits in 10 out of 15 patients in whom surgical results are evaluated. In 3 additional patients the frequency of atonic fits was reduced by more than 50%. In the remaining two patients, no therapeutic effect was observed. Callosotomy was less effective on seizures which were not atonic. Therefore, this procedure appears to be indicated in patients in whom atonic fits are predominant. The main effect of callosotomy is to transform drug-resistant seizures into drug-sensitive ones. Neuropsychological sequels are insignificant unless the splenium is severed. However, considerable psychic and behavioral improvement was nearly always observed after surgery. Despite the fact that on a therapeutic level results were often satisfactory, a number of practical problems still remain. These concern the full spectrum of indications for callosotomy, the extent of corpus callosum section, choice of methods in severely mentally retarded patients and, finally, the age at which the operation should be carried out.

Functions of the corpus callosum: observations from callosotomy performed for intractable epilepsy.

The effects of complete and partial corpus callosotomy in 6 patients are reported. Only the 2 cases undergoing total callosotomy showed evidence of impaired interhemispheric sensory transfer, related to sectioning of the splenium. Only mild long-lasting neuropsychological deficits were detected. Post-commissurotomy mutism and akinesia appeared in 4 cases, 2 with total, and 2 with partial anterior callosotomy. The short-and long-term effects of corpus callosotomy appear to be related to the extent of the section the creation of lesions during the surgical procedure, and a peculiar organization of cognitive functions in chronic epileptic patients.

The surgical treatment of intracranial abscesses today.

The indications and the results of different surgical procedures for the management of intracranial abscesses are dealt in a cooperative study. Two series, amounting 68 patients altogether, collected in epidemiologically homogeneous areas with high percentage of rural population without adequate medical control, are appraised. Due to the high rate of chronic lesions, particularly in the pre-CT scan era (1968-1975), radical excision was required in 70.6% of cases. Overall postoperative mortality was 14.7%: 7.3% during the hospital stay, mostly due to pyrogenic ventriculitis in patients with large deep located abscesses, and 7.4% for different complications, both intra- and extracerebral, at home or other institutions several months after surgery. 29% of patients recovered completely and 45.6% have only minor disability, only 10.3% remained severely crippled and dependent. The results of the surgery, both in terms of operative mortality and functional recovery seem to depend on the neuropathological background rather than on the kind of therapeutic procedure implemented. Even though it must be acknowledged that at present conservative and minor surgical procedures are more often successfully used, radical excision still appears to keep far from negligible indications.

Callosotomy for the management of intractable non-focal epilepsy: a preliminary personal assessment.

After reviewing the data of the literature, the authors report their personal series composed of twelve cases. In evaluating the results of surgical treatment only the first ten patients are taken into account. As previously stressed in the literature, callosotomy (total in two cases and anterior in the remainder) has proved effective in abolishing or significantly reducing atonic seizures. Tonico-clonic seizures have also benefitted in some cases, while in complex partial and partial seizures the effects of callosotomy have been so far unpredictable, albeit in some patients all kinds of seizures have been abolished or definitely reduced. The most impressive EEG and neuropsychological features after callosotomy are briefly summarized. Anterior callosotomy seems to be a relatively safe procedure, its results appear to be, on the whole, gratifying even though in patients with severe mental retardation and Lennox-Gastaut syndromes remain controversial.

Neuropsychological changes after callosotomy in drug-resistant epilepsy: a study of the short-term evolution.

With the increasing interest in callosotomy as treatment for intractable epilepsy, it seems to be important to define the neuropsychological consequences of the related surgical operation. 8 patients suffering from drug-resistant seizures underwent section of the corpus callosum, 6 in the anterior part only and 2 undergoing complete two-stage commissurotomy including the posterior part. Before the callosotomy the patients were studied using a cognitive, affective and behavioural battery which was repeated 15 and 90-100 days after the operation. The patients with sufficient I.Q. were described in more detail using the cognitive parameters; the social and motor behaviour of Lennox-Gastaut subjects are accurately reported. No disconnection syndrome was ever observed after the partial commissurotomy while it occurred in one of the two complete callosotomies. The patients showed longer reaction times and a mild impairment of linguistic, praxic, memory and motor functions in the former evaluation (15 days), but there was consistent improvement in the latter check up. At the 90-100 day follow-up the Lennox-Gastaut patients responded more readily to the environmental stimulations and their postural, motor and behavioural functions were unchanged or improved, with respect to presurgical performances. The social and emotional behaviour of all the patients had always improved by the time the long-term evaluation (90 days) was performed. Finally, by limiting the callosotomy to the anterior part only, the neurological and psychological consequences seem to be limited.(ABSTRACT TRUNCATED AT 250 WORDS)