PubMed Health⌕ Search

Biomedical subjects

Shizuo Oi

Publications and source records attributed to Shizuo Oi.

13 recordsLinked to original sources
PubMed2005

Huge arachnoid cyst incorporating choroid plexus.

BACKGROUND: We report a rare case of arachnoid cyst incorporating choroid plexus. This 7-month-old girl presented with macrocrania. Magnetic resonance (MR) imaging disclosed a cystic lesion arising from the left prepontine cistern extending to the left middle cranial fossa. METHODS: First, we performed resection of the membrane microscopically and obtained an adequate reduction of the cystic size. However, 4 months after the first operation, the cyst was enlarged again, and bulging of the portion of the craniotomy was noted. Thus, we performed neuroendoscopic transcortical ventriculo-cyst-cysternostomy and confirmed the choroid plexus inside of the arachnoid cyst. DISCUSSION: Postoperative course was uneventful. This is the first reported case of choroid plexus within an arachnoid cyst, determined neuroendoscopically.

Arachnoid Cysts↗
PubMed2005

Endoscopic biopsy interpretation difficulties in a congenital diffuse intracranial teratoma.

INTRODUCTION: Congenital brain tumours are a rare entity that is nowadays often already recognised during pregnancy by ultrasound (US) and magnetic resonance (MR). Even though the definitive diagnosis is usually achieved by means of histological studies, in some cases the diagnosis may remain uncertain because of the malformative origin of this type of tumour. CASE REPORT: We describe a patient with a diffuse congenital intracranial mass diagnosed by intrauterine US and foetal MR performed to further evaluate the lesion and the associated foetal hydrocephalus. After delivery by caesarean section, an endoscopic biopsy was performed. Several specimens were obtained and resulted in the diagnosis of primitive neuroectodermal tumour (PNET). Despite polychemotherapy, the tumour continued to enlarge and the patient died at 2 months of age. Post-mortem histological examination of the intracranial mass showed a diffuse intracranial teratoma. CONCLUSION: Endoscopic biopsy specimen examination resulted in a diagnosis that was not confirmed by post-mortem findings. The scarce differentiation of teratoma components and their high variability in histomorphology as well as the huge size of the tumoral mass may limit the interpretation of endoscopic biopsy specimens, even when multiple and obtained from different areas.

Biopsy↗
PubMed2005

Fetal hydrocephalus, intrauterine diagnosis and therapy considerations: an experimental rat model.

MATERIALS AND METHODS: Fetal hydrocephalus is induced by a single intraperitoneal injection of 8 mg/kg 6-aminonikotinamide (6-AN), a niacinamide antagonist, in Sprague-Dawley rats on day 13 of gestation. Laparotomy was carried out in some rats 3, 6, 7 and 8 days after the intraperitoneal injection. The fetuses were collected by uterotomy and fixed in a formalin solution after measuring head circumference and body length for further histological investigations. The ventricular areas and volumes of the lateral ventricles were measured using a computer morphometric technique after all fetuses were serially sectioned sagittally or coronally. Furthermore, 8 maternal rats (4 treated with 6-AN and 4 controls) were used for ultrasound investigation. The fetal ventricular system and the central canal were demonstrated and compared by transabdominal ultrasound in the 6-AN and control groups. On day 19 of gestation the cerebrospinal fluid (CSF) was drained in some fetuses for 18 h through a thin micro-catheter, which was inserted into the lateral ventricle. In some other fetuses the intracranial pressure (ICP) and the intra-amniotic pressure (IAP) were measured after Doppler sonography of the cerebral blood flow (CBF). These measurements were carried out using a transuterine approach following the laparotomy. RESULTS: Hydrocephalus was produced due to the closure of all outlets of the fourth ventricle. Macrocephalus was clear on day 17 (4 days after 6-AN injection). The entire ventricular system was dilated, including the aqueduct and foramen of Monro, and cerebellar hypoplasia was revealed. CONCLUSION: Increased ICP in 6-AN fetuses was associated with decreasing CBF. The cerebral mantel was better developed after CSF drainage. The intra-amniotic pressure was increased in all pregnant rats and was either similar to or higher than ICP.

6-Aminonicotinamide↗
PubMed2005

RNA expression analysis of a congenital intracranial teratoma.

Congenital intracranial tumors are extremely rare and account only for 0.5%-1.5% of brain tumors in children. We report a large intrauterine congenital teratoma in a female fetus at gestation weeks 37, which was diagnosed by detecting the tumor and associated craniomegaly with ultrasonography (US) and magnetic resonance (MR) imaging. The tumor had replaced the cerebral hemispheres and produced prenatal manifestations. Pathologic examination showed an immature teratoma, which was differentiated from all three germ layers. Microarray analysis revealed upregulation of ten genes and downregulation of three genes, as well as upregulation of 41 genes of ribosomal proteins in teratoma cells, compared to normal brain tissue of the patient. The data from the microarray analysis offer not only the potential to help define disease pathogenesis but may also provide clues to identify potential molecular therapeutic targets.

Adult↗
PubMed2004

A case of progressive myelopathy with atlas hypoplasia in an infant: controversy in the surgical strategy.

CASE REPORT: The authors report a case of isolated atlas hypoplasia in an 18-month-old infant who experienced delayed motor development confined to the lower extremities, in the absence of other clinical features. Nonetheless, MRI revealed the upper cervical cord to be highly compressed with a high signal intensity lesion apparent at the craniovertebral junction. The patient underwent atlas laminectomy in addition to occipital decompression, resulting in a good neurological recovery. DISCUSSION: We speculate on the significance of this unique clinical presentation and discuss surgical strategies for this condition.

Cranial Fossa, Posterior↗
PubMed2004

Indication for and surgical outcomes of the distraction method in various types of craniosynostosis. Advantages, disadvantages, and current concepts for surgical strategy in the treatment of craniosynostosis.

BACKGROUND: Various surgical techniques for the treatment of craniosynostosis using distraction devices have been described over the last few years and we have applied these procedures in seven patients with varying types of craniosynostosis. The aim of this report is to clarify the advantages and disadvantages of these surgical methods and to discuss current concepts for the surgical strategy in the treatment of craniosynostosis. MATERIAL AND METHODS: From January 2001 to March 2003, 25 patients with craniosynostosis were examined. Among them, 7 patients, 5 with Apert syndrome, 1 with Crouzon disease, and 1 with multiple-synostosis, underwent surgical treatment using the distraction method with internal distraction devices, according to our treatment strategy for craniosynostosis. All patients underwent preoperative and postoperative evaluations, which included the patient's neurological state, developmental quotient (DQ), and three-dimensional CT (3D-CT). RESULTS: The timing of the procedures undertaken was between the ages of 1 year 5 months and 12 years 6 months (mean age 4 years 11 months). Five patients had received previous treatment and this procedure was used as a secondary operation. Postoperative distraction distances varied from 7 to 20.5 mm (mean distraction distance: 14 mm). Satisfactory cranial volume expansion and aesthetically pleasing morphological states were achieved in all cases. Regarding complications, one patient required re-operation because of dislocation of the device and skin erosion caused by infection around the penetrated wound. Finally, in a second patient a distortion of the device occurred, but no re-operation was needed. CONCLUSION: The advantage of the distraction method is its applicability for Toddler or Elder Children Calvarial Reconstruction to correct cosmetic and functional problems. One disadvantage is the difficulty in using it for Infantile Calvarial Normalization because of thin calvarial bones and the necessity for re-operation to remove the device, which may result in it becoming a "fixation procedure," essentially contraindicated for the fast-developing brain and calvarias. However, the efficacy of this procedure is that the many advantages outweigh the disadvantages as sufficient calvarial expansion and good results using the distraction method, especially in toddler and elder children age groups, can be achieved.

Age Factors↗
PubMed2004

Loculated ventricles and isolated compartments in hydrocephalus: their pathophysiology and the efficacy of neuroendoscopic surgery.

The neuroendoscopic procedures applied inpatients with isolated compartments, including IUH, LV, IFV, IRF, and multiloculated ventricles were foramen of Monro reconstruction, septostomy, septal wall removal, cyst wall fenestration, fourth ventriculostomy, and endoscopic shunt placement. It was found that the operative goal, creating a state of arrested hydrocephalus, could be achieved by communicating the trapped space to the rest of the ventricular system, opening the ventricular isolation. The associated hydrocephalus could not always be managed endoscopically, however, and shunting of the ventricular system was frequently required, especially in infants. This may be because of the immaturity of the subarachnoid CSF dynamics in infants. What does seem to be logical is to continue to consider managing these conditions with the assistance of the endoscope.

Cerebral Ventricles↗
PubMed2003

"Hydrocephalus-parkinsonism complex": progressive hydrocephalus as a factor affecting extrapyramidal tract disorder-an experimental study.

OBJECTIVE: To experimentally clarify the symptomatological and pathophysiological aspects of a newly proposed clinical entity, we produced an experimental rat "hydrocephalus-parkinsonism complex" model. METHODS: A total of 60 male Sprague-Dawley rats were used. Twenty rats were treated with only kaolin as controls. Hemiparkinsonism was induced in the other 40 rats by stereotactic injection of 6-hydroxydopamine (6-OHDA) directly into the right substantia nigra. Twenty of these 40 rats were then treated with an injection of kaolin into the cisterna magna 3 days after the induction of parkinsonism. Neurological features were assessed weekly for 1 to 6 weeks after 6-OHDA injection by an apomorphine-induced turning test. RESULTS: The mortality rate was 25% in the rats injected with kaolin and 10% in those with the 6-OHDA injection. The frequency of the induction of parkinsonism-like signs was minimal in the first 2 weeks and reached a maximum point 4 weeks after the 6-OHDA injection. In contrast, the rats injected with both 6-OHDA and kaolin developed hemiparkinsonism-like signs in the early stage of the progression of hydrocephalus, and the peak incidence was reached in the 2nd week after induction ( p<0.05 compared with the 6-OHDA group). The severity of the neurological disturbance was also significantly more prominent in the latter group. CONCLUSION: These results suggest that the hydrodynamic effect in the early period of ventriculomegaly is the mechanism for signs of parkinsonism in 6-OHDA-treated rats. It could be concluded that the hydrocephalic state aggravates parkinsonism, if any as the associated condition, and it may be a new clinical entity of hydrocephalus symptomatology with a specific pathophysiology.

Animals↗
PubMed2003

Diagnosis, outcome, and management of fetal abnormalities: fetal hydrocephalus.

INTRODUCTION: It has been recognized that the morphological fetal CNS findings detected in early development are not always the final features: occasionally they may not be determined in diagnosis and may change developmentally or chronologically during the fetal life in utero. DISCUSSION: Certain factors of the fetal chronology of CNS anomalies can cause irreversible changes during fetal life. These include: significant delay in the neuronal maturation process in fetal hydrocephalus developed in clinico-embryological stage II of the Perspective Classification of Congenital Hydrocephalus (PCCH), secondary neural injury in the intactly developing spinal cord above the neural placode in fetuses with spina bifida aperta (myeloschisis), histological "evolution" of tumors or dysgenetic CNS, and deformity of the normally developed intracranial or intraspinal CNS structures. Considering the current status of fetal surgery in general and technical advances promising improved outcomes, fetal neurosurgery can also be applied to the above-mentioned progressive pathology or pathophysiology in the fetal CNS. However, since the failure of the first trial of fetal neurosurgery in the 1980s, the prerequisites have still not been clarified. In order to use advanced neurosurgery techniques in the management of fetal CNS anomalies, these prerequisites have to be established.

Animals↗
PubMed2003

Current status of prenatal management of fetal spina bifida in the world: worldwide cooperative survey on the medico-ethical issue.

INTRODUCTION: The management of congenital CNS anomalies differs among countries. This paper reports on a worldwide survey of individual experience and regimens for treating spina bifida (SB) in different patient populations and cultural backgrounds. Ten representative members of the International Society for Pediatric Neurosurgery (ISPN) in individual countries registered their experience, prenatal management, and care system for SB. The information collected contained the following major items: intrauterine diagnosis, prophylaxis, and legal termination in prenatal management. DISCUSSION: The prenatal diagnosis of SB is extensively performed throughout the world, but the marker alpha-fetoprotein is not widely accepted in Asia, nor is the prophylactic administration of folic acid, which is not part of the routine care in Asia. Morphological analyses by neuroimaging, especially using an advanced technique of magnetic resonance imaging (MRI), are well developed in Asian countries, e.g., Japan and Korea. The prenatal management of SB fetuses differed depending upon the region, i.e., more support for aggressive and intensive treatment in Asia than in Europe and North America. The regional and racial difference in management of and care for spina bifida fetuses will be discussed further based on the data analysis.

Child, Preschool↗
PubMed2002

Neuroendoscopic placement of Ommaya reservoir into a cystic craniopharyngioma.

INTRODUCTION: Total removal of the tumor is the most acceptable therapeutic modality in the management of craniopharyngioma; however, there are innumerable factors that can upset treatment plans. Unresectable lesions are often treated with gamma knife surgery (GKS). Reduction of the cystic volume is necessary, to decrease the area to be treated with GKS. An Ommaya reservoir system is usually placed during open surgery or by stereotactic access. MATERIALS AND METHODS: The authors use a neuroendoscope for safer and less invasive placement of the Ommaya reservoir into deep-seated cystic lesions. The cystic component is aspirated, and the Ommaya reservoir tube is precisely guided and placed into the cyst cavity under neuroendoscopic control with a newly developed two-burr-hole technique. This neuroendoscopic procedure could make it easier to reduce cystic volume prior to GKS as the final procedure. This technique may also be used for instillation of chemotherapeutic agents and for repeat aspirations, making the achievement of cystic control more likely. This type of neuroendoscopic management is a safe and effective procedure and could be considered as an alternative management technique for some stubborn cystic craniopharyngiomas.

Catheterization↗
PubMed2002

Endoscopic third ventriculostomy in patients with cerebrospinal fluid infection and/or hemorrhage.

OBJECT: In this study the authors evaluate the safety, efficacy, and indications for endoscopic third ventriculostomy (ETV) in patients with a history of subarachnoid hemorrhage or intraventricular hemorrhage (IVH) and/or cerebrospinal fluid (CSF) infection. METHODS: The charts of 101 patients from seven international medical centers were retrospectively reviewed; 46 patients had a history of hemorrhage, 42 had a history of CSF infection, and 13 had a history of both disorders. All patients experienced third ventricular hydrocephalus before endoscopy. The success rate for treatment in these three groups was 60.9, 64.3, and 23.1%, respectively. The follow-up period in successfully treated patients ranged from 0.6 to 10 years. Relatively minor complications were observed in 15 patients (14.9%), and there were no deaths. A higher rate of treatment failure was associated with three factors: classification in the combined infection/hemorrhage group, premature birth in the posthemorrhage group, and younger age in the postinfection group. A higher success rate was associated with a history of ventriculoperitoneal (VP) shunt placement before ETV in the posthemorrhage group, even among those who had been born prematurely, who were otherwise more prone to treatment failure. The 13 premature infants who had suffered an IVH and who had undergone VP shunt placement before ETV had a 100% success rate. The procedure was also successful in nine of 10 patients with primary aqueductal stenosis. CONCLUSIONS: Patients with obstructive hydrocephalus and a history of either hemorrhage or infection may be good candidates for ETV, with safety and success rates comparable with those in more general series of patients. Patients who have sustained both hemorrhage and infection are poor candidates for ETV, except in selected cases and as a treatment of last resort. In patients who have previously undergone shunt placement posthemorrhage, ETV is highly successful. It is also highly successful in patients with primary aqueductal stenosis, even in those with a history of hemorrhage or CSF infection.

Adolescent↗