José Píndaro Pereira Plese

Transient mutism following a posterior fossa approach to cerebellar tumors in children: a critical review of the literature

Transient mutism has been known as a rare complication following a posterior fossa approach to cerebellar tumors and its cause has not been clearly elucidated. The cerebellar mutism is not accompanied by cranial nerve deficits and disorders of consciousness. Since 1985 only 23 cases of mutism following removal of a cerebellar tumor in children have been reported in the literature. Two additional cases have been operated upon in our department. Extensive injury to the vermian and paravermian cerebellar area, involving the hemispheric cortex, cerebellar peduncles, fibers from the dentato-thalamocortical pathway, and dentate and interpositum nuclei may be the most important anatomical substrate of mutism. The mechanism of such transient mutism seems to be a complex of two or more factors (vascular disturbances due to manipulation or retraction of the cerebellar region around the IV ventricle and emotional factors). On the basis of these 25 cases the major features of the cerebellar mutism are discussed.

Steroid receptors in intracranial tumors

Cytosolic estrogen (ER), progesterone (PR), androgen (AR), and glucocorticoid (GR) receptors were evaluated in 6 meningiomas and 12 gliomas (6 astrocytomas and 6 glioblastomas) using a dextran-coated charcoal method. Thirty-three percent (two) of the meningiomas and 17% (two) of the gliomas contained positive (≥ 10 fmol/mg protein) but low ER levels. On the other hand, positive PR, GR, and AR levels were detectable in 100% (six) of the meningiomas. PR was present in 50% (six), AR in 42% (five), and GR in 58% (seven) of the gliomas. PR, GR, and AR values were statistically higher in meningiomas than in neuroepithelial tumors.

Apert syndrome: factors involved in the cognitive development.

Apert syndrome is characterized by craniosynostosis, symmetric syndactyly and other systemic malformations, with mental retardation usually present. The objective of this study was to correlate brain malformations and timing for surgery with neuropsychological evaluation. We also tried to determine other relevant aspects involved in cognitive development of these patients such as social classification of families and parents education. Eighteen patients with Apert syndrome were studied, whose ages were between 14 and 322 months. Brain abnormalities were observed in 55.6% of them. The intelligence quotient or developmental quotient values observed were between 45 and 108. Mental development was related to the quality of family environment and parents education. Mental development was not correlated to brain malformation or age at time of operation. In conclusion, quality of family environment was the most significant factor directly involved in mental development of patients with Apert syndrome.

Hydrocephalus due to diffuse villous hyperplasia of the choroid plexus: Case report and review of the literature

Diffuse villous hyperplasia of the choroid plexus (DVHCP) that causes hydrocephalus by overproduction of cerebrospinal fluid is a very rare lesion and difficult to diagnose initially. We present a male infant who was diagnosed with communicating hydrocephalus at 16 months of age and treated initially by ventriculoperitoneal shunt. In the postoperative course, he developed massive ascites. Magnetic resonance imaging obtained after the operation revealed DVHCP. Resection of the choroid plexus of the left lateral ventricle was performed, and postoperatively, his ascites was resolved. We review the literature and discuss the diagnosis and treatment of this rare entity.

Correlation between parameters of electrophysiological, histomorphometric and sciatic functional index evaluations after rat sciatic nerve repair

The rat sciatic nerve is a well-established model for the study of recovery from peripheral nerve injuries. Traditional methods of assessing nerve regeneration after nerve injury and repair, such as electrophysiology and histomorphometry, despite widely used in neural regeneration experiments, do not necessarily correlate with return of motor and sensory functions. The aim of this experimental study is to investigate the possible correlation between several parameters of peripheral nerve regeneration after repair of sectioned sciatic nerve in Wistar rat. A two-stage approach was used to obtain 17 parameters after electrophysiological, morphometric and sciatic functional index evaluations. Pearsons correlation analysis was performed between these results. Only two positives correlations between different classes of peripheral nerve assessments were noted, between sciatic functional index and proximal nerve fiber diameter (r=0.56, p<0.01) and between sciatic functional index and distal fiber diameter (r=0.50, p<0.01). The data presented in our study demonstrates that there is a poor correlation between the sciatic functional index and outcome measures of electrophysiological and morphometric evaluations.

Electrophysiologic assessment of regeneration in rat sciatic nerve repair using suture, fibrin glue or a combination of both techniques

We evaluated the repair of sectioned rat sciatic nerve by the comparison of electrophysiologic parameters. The repair was effected with suture (group A), fibrin glue (group B) or a combination of both techniques (group C). The amplitude, latency and conduction velocity of the motor and nerve action potentials were assessed before the nerve section and at reoperation after 24 weeks. There was no difference between the groups when the nerve action potential was evaluated. Rats of group B presented better results than those of group A (p<0.05) when latency and the nerve conduction velocity assessed at the reoperation, and the ratio between the conduction velocity at the reoperation and before the nerve section in the motor action potential evaluation were measured. Animals of group C presented better results than those of group A when the ratio between the conduction velocity of motor action potential at the reoperation and before the nerve division was considered (p<0.05). No difference between groups B and C was found. We conclude that repair using fibrin glue presented better results than suture following transection of sciatic nerve when the motor action potential was evaluated in the rat experimental model.

Leptomeningeal dissemination of pilocytic astrocytoma at diagnosis in childhood: two cases report

Pilocytic astrocytoma (PA) is a benign tumor that rarely spread along the neuraxis. At the moment there are no more than five cases of leptomeningeal dissemination (LD) from PA at diagnosis described in the literature. Different patterns of presentation or recurrence may be noted: local recurrence, malignant transformation, multicentric disease or metastatic disease. LD and multicentric disease can be distinct pathological entities. We report two cases and analyse literature, emphasizing leptomeningeal spread at presentation. Hydrocephalus, biopsy and parcial ressection are likely to be favorable factors to the occurrence of LD. Otherwise, LD may be part of natural history of PA, as evidenced by its ocurrence in non-treated cases.

Proliferation rate of intracranial meningiomas as defined by the monoclonal antibody MIB-1

Paraffin-embedded surgical specimens from 55 meningiomas were immunostained after microwave processing using the streptavidin/peroxidase method and the monoclonal antibody (moAb) MIB-1 to the Ki-67 antigen. The authors assessed proliferative labelling index (LI) from a series of surgically removed meningiomas using immunohistochemical methods and MIB-1, and they correlated this index with clinical, radiological, and histological factors. No relationship was found between LI, sex, age, resection and histological grades, or volume. Symptoms, location, and peritumoural oedema did have a significant relationship to the MIB-1 LI. The symptomatic patients, i.e. those with tumours at the base of the skull and with GR3 peritumoural oedema (grade 3), had a greater chance of higher MIB-1 LI. It was proven that the increase of one unit in peritumoural oedema classification gave an increased risk of 3.312 and an LI greater than 3%. The authors also discuss the different methods of evaluating LIs in meningiomas, based on the available literature.

CSF markers for diagnosis of bacterial meningitis in neurosurgical postoperative patients

OBJECTIVE To evaluate the diagnostic usefulness of cerebral spinal fluid (CSF) cellularity, protein, neutrophils, glucose and lactate for detection of postoperative bacterial meningitis. METHOD This prospective study was conducted in 28 postoperative neurosurgical patients from 2002 to 2005 at University of São Paulo. The CSF markers were plotted in a receiver operating characteristic (ROC) curve to evaluate their accuracy. RESULTS Based on the area under ROC curve CSF glucose, cellularity, and lactate were considered good tests. Polymorphonuclear and protein did not achieve enough accuracy to be used clinically. CONCLUSION The CSF glucose, lactate, and cellularity can be used for the diagnosis of bacterial meningitis. Moreover, it can be helpful to differentiate bacterial from aseptic meningitis.

Edema and malignancy in meningiomas

PURPOSE In recent years there have been many attempts to define a subset of aggressive malignant meningiomas based on histopathology and imaging technologies. The purpose of this study was to evaluate the level of peritumoral edema and its volume using the imaging technologies, computer tomography and magnetic resonance imaging, and correlate these results with the histological WHO classification. Reported causes of tumoral edema and its relationships to the histological characteristics were also reviewed. METHODS The cases of 55 patients with meningiomas who underwent surgery at the Hospital das Clinicas (Fac Med Univ Sao Paulo) between September 1993 and September 1997 were reviewed. The level of edema according to the classification of Ide et al. (1995) was compared to the histological WHO classification. RESULTS Classification of the degree of edema was: level 0 edema--28 cases ; level I edema--19 cases; level II edema--8 cases. Histological classification was: benign meningioma--43 cases; atypical meningiomas--11 cases; malignant meningioma--1 case. There was a significant (P=.0089) correlation between the degree of tumoral edema and the histological characteristics. CONCLUSIONS These results suggest that the degree of edema as revealed by computer tomography and magnetic resonance imaging can be an important clinical predictive factor for the histological grade of the meningioma.