Mutism is an infrequent and transitory complication observed following posterior fossa surgery. Patients become mute in the immediate postoperative period, with restoration of speech within a few weeks in the absence of additional neurological alterations. The anatomical structures thought to be involved are the connections between the cerebellar dentate nucleus, the ventrolateral nucleus of the contralateral thalamus and the supplementary motor area. In an attempt to understand the pathophysiology of this syndrome, and to depict the perfusion of different brain areas semiquantitatively, in two children who had become mute after posterior fossa surgery we performed a Tc99M-HM-PAO SPECT study during the period of mutism and again when normal speech had returned. In one patient, who had a left cerebellar astrocytoma, the SPECT study showed a marked reduction of cerebral perfusion in the right fronto-parietal region, and in the other, who had a medulloblastoma, a left fronto-temporo-parietal perfusion alteration was observed. When the patients regained normal speech, the follow-up SPECT studies revealed normalization of the cerebral perfusion. This study demonstrates the occurrence of a focal dysfunction of cerebral perfusion in children with cerebellar mutism after posterior fossa surgery. These observations are useful in extending our understanding of the pathophysiology of this postoperative clinical syndrome.

Gram-negative bacterial infections of the central nervous system are generally associated with high morbidity and mortality rates. In patients with ventriculitis induced by gram-negative liquoral sepsis, a reduction in cerebrospinal fluid formation has been reported, suggesting that gram-negative ventriculitis is able per se to alter the normal functioning of the choroid plexus. The aim of the present study was to analyse, for the first time in the rat, the effects of acute ventriculitis on the ultrastructure of the choroid plexus. A simple and inexpensive experimental model of acute ventriculitis was developed: we injected into the cisterna magna of rats 10(3) CFU of live Escherichia coli, inducing septic ventriculitis without major neurological deficits. Histological examinations of rodent choroid plexus 24 h after the injection revealed patches of altered epithelium, with swollen and vacuolated ependymal cells associated with leukocyte infiltration. Electron microscopy demonstrated a reduced number of microvilli and flattening of the epithelial surface. These results (a) indicate that gram-negative septic ventriculitis is able to induce visible ultrastructural alterations of the choroid plexus which (b) are consistent with a picture of marked reduction of the functioning epithelial choroid plexus surface, and (c) highlight the potential usefulness of our rodent acute ventriculitis model for developing treatment modalities.

Several intracranial pressure monitoring devices have been developed in the past several years. We have recently adopted the Camino fiberoptic device that permits subdural, intraparenchymal, and intraventricular monitoring. In this report we compare experiences in monitoring a group of pediatric patients with severe craniocerebral trauma and coma, grouped according to severity of Glasgow Coma Scale score. Patient age ranged from 2 to 16 years. Twelve patients were monitored by a ventricular catheter and 37, treated more recently, by a Camino fiberoptic device. The study demonstrated that the fiberoptic device and the ventricular catheter have the same accuracy and reliability. The fiberoptic method correlates very closely with the ventriculostomy method, but the pressure values are always 3 +/- 2 mmHg lower than those obtained with the conventional pressure transducer system, especially in more critically ill patients. This new technique is also easier to implant, safer to use, has minimal drift, and is minimally invasive, which particularly speaks for its use in pediatric patients.

Osteoclastoma is a rare skeletal lesion, characterized by large multinucleated giant osteoclastic cells; this lesion usually affects young adults with a prevalence of 1 case/1 million population. We report the case of a 9-year-old girl with a right temporal tumescence: X-ray, CT and MRI revealed the presence of a right temporal hyperostotic ring-like area over the lambdoid suture, with irregular margins and calcareous deposits. The tumour was expanding mainly toward the endocranium involving both cranial tables and diploë, without infiltrating the brain parenchyma. The child underwent complete microsurgical removal of the lesion. Histopathological findings revealed the giant cell tumour osteoclastoma. Correct modern preoperative neuroimaging workup, coupled with microneurosurgical technique, allowed successful lesion removal with good outcome. A review of the more recent literature and of mechanisms of pathology together with neuroradiological protocol and results of treatment are discussed.

Symptomatic spinal cord compression caused by an epidural mass of extramedullary hematopoietic tissue in patients with β-thalassemia is a rare occurrence, that becomes exceptional in childhood and adolescence. The literature is not uniform about the optimal treatment of these patients and different modes of therapy have been proposed so far, including surgical excision or decompressing laminectomy followed by local irradiation and/or hypertransfusional regimens. We report the successful treatment of such a complication in an adolescent with homozygous β-thalassemia by surgery followed by repeated blood transfusions aimed at maintaining hematocrit at normal levels.