Enlargement of sacral subcutaneous meningocele associated with retained medullary cord.

BACKGROUND: A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac. Four cases of RMC extending down to the base of an associated subcutaneous meningocele at the sacral level have been reported. CLINICAL PRESENTATION: We report an additional case of RMC, in whom serial MRI examination revealed an enlargement of the meningocele associated with RMC over a 3-month period between 8 and 11 months of age, when he began to stand. At the age of 12 months, untethering of the cord was performed. Histologically, the presence of ependyma-lined central canals in the dense neuroglial cores was noted in all cord-like structures in the intradural and intrameningocele sacs and at the attachment to the meningocele. CONCLUSION: It is conceivable that the hydrodynamic pressure with standing position and the check valve phenomenon were involved in meningocele enlargement. We should be mindful of these potential morphological changes.

Neurosurgical pathology of limited dorsal myeloschisis.

PURPOSE: The term limited dorsal myeloschisis (LDM) was used by Pang et al. (2010) to describe a distinct clinicopathological entity. LDMs are characterized by two invariable features: a focal-closed neural tube defect and a fibroneural stalk that links the skin lesion to the underlying spinal cord. METHODS: We retrospectively analyzed the neurosurgical pathologic findings of four LDM patients. RESULTS: Case 1 had a saccular skin lesion with nonterminal abortive myelocystocele at T11-12. Cases 2, 3, and 4 had a non-saccular (flat) skin lesion in the lumbosacral region. The morphologic features of the lesion in case 2 were those of meningocele manque. Cases 3 and 4 had accompanying non-LDM anomalies, caudal-type lipoma and type II split-cord malformation with neurenteric cyst, respectively. At preoperative diagnosis of the LDM stalk, magnetic resonance imaging, including 3D heavily T2-weighted image was useful; however, minute findings were often missed in the complicated cases 3 and 4. All patients had a favorable outcome following untethering of the stalk from the cord. The central histopathological feature of the LDM stalk is neuroglial tissue in the fibrocollagenous band; however, the stalk in cases 2 and 4 did not have glial fibrillary acidic protein-immunopositive neuroglial tissues. CONCLUSIONS: Therefore, the diagnosis of LDM should be made based on comprehensive evaluation of histologic and clinical findings.

Ependyma-Lined Canal with Surrounding Neuroglial Tissues in Lumbosacral Lipomatous Malformations: Relationship with Retained Medullary Cord.

BACKGROUND: An ependyma-lined canal with surrounding neuroglial tissues can be present in lumbosacral lipomatous malformations; however, the precise embryological significance is still unclear. METHOD: Six out of 50 patients with lipomatous malformations had ependymal structures. We retrospectively analyzed the clinical, neuroradiological, and histological findings of these patients to demonstrate the relationship with the embryological background of the retained medullary cord (RMC), which normally regresses, but was retained here because of late arrest of secondary neurulation. RESULTS: Five (13.9%) of 36 patients with filar and caudal types and 1 of 3 lipomyelomeningoceles had ependymal structures, while none with dorsal and transitional types had these tissues. Histologically, the ependymal structures surrounded by neuroglial tissue and containing various amounts of adipose tissue bear a striking resemblance to the ependymal structures in RMC. CONCLUSION: The 13.9% incidence of association between the ependymal structures and filar and caudal types is thought to be because of second ary neurulation failure with the same embryological background as that of RMC. Dorsal and transitional types, resulting from primary neurulation failure, therefore, did not have ependymal structures.

A Presenile Patient with Filar Lipoma Who Developed Tethered Spinal Cord Syndrome Triggered by Lumbar Canal Stenosis.

Lumbar canal stenosis (LCS) has been reported as a precipitating factor by which a tethered spinal cord, which is asymptomatic during childhood, develops into tethered cord syndrome (TCS) in adulthood. However, only a few reports on surgical strategies for such cases are available. A 64-year-old woman presented with unbearable pain in the left buttock and dorsal aspect of the thigh approximately 1 year ago. Magnetic resonance imaging showed cord tethering with a filar-type spinal lipoma and LCS due to the thickening of the ligamentum flavum at the L4-5 vertebral level. Five months after the decompressive laminectomy for the treatment of LCS, an untethering surgery was performed at the dural cul-de-sac at the S4 level. The severed end of the filum was elevated rostrally by 7 mm, and the pain subsided postoperatively. This case study shows that surgeries for both lesions should be indicated for adult-onset TCS triggered by LCS.

Lessons Learned from Mechanical Thrombectomy of an Acute Occlusion of a Duplicated Middle Cerebral Artery: A Case Report.

Objective: Detection of acute arterial occlusion in an anomalous middle cerebral artery (MCA) is challenging in an emergency setting because of its rarity. Case Presentation: We report an 81-year-old woman who presented with acute occlusion of a duplicated middle cerebral artery (DMCA). Although the absence of the superior trunk of the left MCA was identified on preoperative imaging, initial angiography showed no typical sign of the occluded vessel. Repeated angiography eventually revealed retrograde arterial flow parallel to the other visible MCA trunk, which raised the possibility of a DMCA. The occlusion occurred at the origin of the DMCA originating from the internal carotid artery terminus, which obscured its presence. Mechanical thrombectomy was performed and achieved complete recanalization. The DMCA had two trunks of approximately equal size. The patient completely recovered within 90 days. Conclusion: Comprehensive knowledge of cerebrovascular anomalies is essential to identify the occluded branch faster and accurately and to avoid thrombectomy-related complications in endovascular recanalization therapy. Relevant DMCA anatomy and tips for identifying an occluded DMCA are discussed.

[A case of petrous ridge meningioma manifested as pneumocephalus followed by Eustachian tube insufflation].

A 50-year-old female, who had a headache after Eustachian tube insufflation for her ear congestion, came to our hospital. CT and MRI revealed pneumocephalus and petrous ridge meningioma which destroyed petrous bone and air cells. Eustachian tube insufflation was considered to make the air coming into the middle ear, mastoid air cell and then into the intracranial space destroying the tumor. At surgery, there was subdural hematoma around the tumor. Total removal of the tumor and the hematoma membrane was performed. Histologically, the tumor was transitional meningioma and the cluster of meningioma cells were noted in the subdural hematoma membrane.

[Four cases of direct surgery for anterior inferior cerebellar artery aneurysms].

Anterior inferior cerebellar artery (AICA) aneurysms are very rare. We carried out four direct operations for AICA aneurysms including two distal AICA aneurysms using lateral suboccipital retrosigmoid approaches (LSRA). We successfully performed the clipping by LSRA. but hearing loss occurred except in one of our cases which involved a chronic term operation in in our cases, In a 72 years old female with a ruptured dissecting aneurysm of the AICA anterior pontine segment, we performed the OA-PICA anastomosis first because of its being an AICA-PICA type, and then we continued to carry out the trapping operation of dissecting artery on day 0. She left our hospital cheerfully but hearing loss persisted on the operated side. Four examples of the dissecting aneurysm of AICA anterior pontine segment have been reported, but only our case involved the trapping with revascularization in acute stage. At the moment, there is no clinical or useful classification for distal AICA aneurysm because it is extremely rare. We will now propose a new classification. This classification is divided into two groups, (1) P (pons) -group and (2) C (cerebellum) -group. The P-group consists of pA (AICA anterior pontine segment). pL (lateral branch on the pons to the meatal loop) and pM (medial branch on the pons). C-group consists of m-loop (meatal loop), cL (lateral branch post meatal loop) and cM (medial branch on the cerebellum). From results of case reports (75 distal AICA aneurysms), we found that pA: 5 (6.7%), pL: 2 (2.8%), pM: 0, m-loop: 54 (72%), cL: 8 (11%), cM: 6 (8.3%). The followings factors were also found. (1) Occlusion of the parent artery of P-group without revascularization of peripheral circulation may entail the risk of death. (2) On the other hand, as for the C-group, the parent artery was able to be occluded without severe consequences, but hearing loss and/or cerebellar infarction occurred. We believe that this classification is simple and very useful for therapeutic strategies in both direct surgery and intravascular treatments for distal AICA aneurysms.

[Seven cases of posterior cerebral artery aneurysms].

In a period of ten years, since January 1996, we have encountered seven cases of posterior cerebral artery aneurysms (0.58% of surgically treated 1027 aneurysms in our hospital). Six of these cases were females (from 39 years old to 73 years old, average 54.5 years old). In five of the cases, neck clippings were performed, using the pterional approach for one P1 and one P2a aneurysm, the remaining three were clipping using the subtemporal approach for one P2a and two P2p aneurysms. In one case diagnosed as "unknown SAH" by typical findings of the CT scan and normal four-vessel study at the time of admission. The second vertebral angiography (two weeks later) revealed a P2a aneurysm. Such a case attracted our interest in the clinic, because many similar cases might have been diagnosed as "unknown SAH". In the case of a 42-year-old male with intracerebral hematoma, four-vessel study made a definite diagnosis as moyamoya disease and revealed a P2a aneurysm, which we cured by embolization of GDC for the preservation of anastomosis networks which had already been formed. Intravascular embolization is very effective, but sufficient studies are required before applying it in the cases of large and/or thrombosed aneurysms. We described surgical approaches about pterional, subtemporal and transchoroidal approaches and discussed some of the differences in the classification methods of Pia, Yasargil, Zear & Rhoton and Seoane. In particular, attention is necessary because we have confused Yasargil's classification with Zeal & Rhoton's classifications by using of the same notation, "Pn".

Impaired intracellular signal transduction via cyclic AMP contributes to cerebral vasospasm in rats with subarachnoid hemorrhage.

No drug can completely prevent vasospasm after subarachnoid hemorrhage. Impaired intracellular signal transduction by cyclic nucleotides might be involved. We investigated effects of intravenous isoproterenol and NKH477 on cerebral blood flow in rats with or without intracisternal injection of autologous blood one week previously. In controls without hemorrhage, isoproterenol at 0.01, 0.1, 1, and 10 mg kg(-1) min(-1) increased cerebral blood flow by 1.2%+/-9.5%, 19.7%+/-12.8%, 46.8%+/-23.5%, and 63.8%+/-32.9% respectively; 10mg kg(-1) min(-1) of isoproterenol increased systemic blood pressure by 66.6%+/-58.1%, while other doses decreased blood pressure. In the subarachnoid hemorrhage group, isoproterenol increased cerebral blood flow by -20.0%+/-6.5%, -7.6%+/-8.7%, 8.2%+/-8.8%, and 35.9%+/-83.1% respectively; 10 mg kg(-1) min(-1) of isoproterenol increased systemic blood pressure by 68.8%+/-79.5%, while other doses decreased blood pressure. In controls, NKH477 at 3, 10, and 30 mg kg(-1) increased cerebral blood flow by 2.3%+/-3.6%, 14.4%+/-7.0%, and 50.7%+/-14.6%, respectively; in the subarachnoid hemorrhage group, NKH477 changed cerebral blood flow by -1.3%+/-2.4%, 4.6%+/-2.8%, and -12.6%+/-10.8% (not significant difference from controls). NKH477 at 30 mg kg(-1) min(-1) decreased systemic blood pressure in both groups, but the effect in the hemorrhage group was greater. Either isoproterenol or NKH477 at appropriate doses can increase cerebral blood flow in vasospasm following subarachnoid hemorrhage without decreasing blood pressure.

Type V phosphodiesterase expression in cerebral arteries with vasospasm after subarachnoid hemorrhage in a canine model.

Cyclic GMP (cGMP) mediates smooth muscle relaxation in the central nervous system. In subarachnoid hemorrhage (SAH), decreases in intrinsic nitric oxide (NO) cause cerebral vasospasms due to the regulation of cGMP formation by NO-mediated pathways. As phosphodiesterase type V (PDE V) selectively hydrolyzes cGMP, we hypothesized that PDE V may function in the initiation of vasospasm. This study sought to identify the altered PDE V expression and activity in the vasospastic artery in a canine SAH model. We also used this system to examine possible therapeutic strategies to prevent vasospasm. Using a canine model of SAH, we induced cerebral vasospasm in the basilar artery (BA). Following angiographic confirmation of vasospasm on day 7, PDE V expression was immunohistochemically identified in smooth muscle cells of the vasospastic BA but not in cells of a control artery. The isolation of PDE enzymes using a sepharose column confirmed increased PDE V activity in the vasospastic artery only through both inhibition studies, using the highly selective PDE V inhibitor, sildenafil citrate, and Western blotting. Preliminary in vivo experiment using an oral PDE V inhibitor at 0.83 mg kg(-1) demonstrated partial relaxation of the spastic BA. PDE V activity was increased from control levels within the BA seven days after SAH. PDE V expression was most prominent in smooth muscle cells following SAH. These results suggest that clinical administration of a PDE V inhibitor may be a useful therapeutic tool in the prevention of vasospasm following SAH.

Effects of single low dose irradiation on subventricular zone cells in juvenile rat brain.

Although the juvenile human brain is relatively radioresistant, irradiation can result in brain growth retardation, progressive mental disturbance, and neurologic abnormalities. As neural stem cells or progenitor cells may be a target of radiation injury and may play an important role in the brain's functional recovery, we examined the effects of whole brain irradiation on these cells in juvenile rat. Six-week-old Wistar rats, where the brain is still growing, were irradiated with single doses of 1, 2, or 3 Gy X-ray. We measured their body and brain weights at 30 or 60 days after irradiation. The chronological changes of the subventricular zone (SVZ) were examined at 6 h, 2, 7, 14, 30, or 60 days after irradiation by immunohistochemistry, specifically looking at the neural stem cells or progenitor cells using anti-nestin antibodies specific for these cells. The rate of brain weight gain of irradiated rats significantly decreased in comparison to controls, although that of body weight gain was similar among them. Multiple apoptotic cells appeared in the SVZ at 6 h after irradiation with simultaneous reduction in nestin-positive cells (69% of the control). The cell levels recovered within a week, with the nestin-positive cells reaching maximal numbers (182%) on Day 14. Nestin-positive cells returned to baseline levels within 30 days (96%) and remained unchanged for the subsequent 60 days. The X-ray dosage did not affect these findings. Our findings revealed that single low dose X-ray administration reversibly affected the levels of neural stem and progenitor cells in the SVZ region. These results suggest that continuous multiple administrations of X-rays in clinical treatment may affect irreversible changes on neural stem or progenitor cells, causing brain growth retardation, or dysfunction.

Occurrence of subdural hematoma and resolution of gait disturbance in a patient treated with shunting for normal pressure hydrocephalus.

A 66-year-old man with gait disturbance was diagnosed with normal pressure hydrocephalus (NPH) and treated with ventriculoperitoneal shunting using a programmable valve. The valve ultimately set at a pressure of 40 mm H(2)O after higher settings no longer relieved symptoms. However, this pressure setting was excessively low and was associated with occurrence of bilateral subdural hematomas. Paradoxically, this event was associated with stable improvement of gait. Our patient's gait disturbance was unassociated with muscle weakness, spasticity, cerebellar ataxia, or Romberg's sign, and, therefore, was consistent with a frontal gait disorder. Cerebral cortical blood flow as measured after shunting by single photon emission computed tomography (SPECT) was slightly increased from the value before shunting, possibly because of intracranial hypotension related to the valve setting. Lasting improvement of gait in our case may be a result of increased blood flow in the supplementary motor area (SMA).

Decreased thalamic metabolism without thalamic magnetic resonance imaging abnormalities following shearing injury to the substantia nigra.

A 36-year-old man had fallen about 8 metres. Radiographs showed a mandibular fracture, indicating rotatory force applied to the head. Fluid-attenuated inversion recovery (FLAIR) imaging showed hyperintensity in both medial temporal lobes, left medial midbrain, right midbrain including cerebral peduncle, left pulvinar, left external capsule, fornix, splenium of corpus callosum, and deep white matter of both frontal lobes. Quantitative [(18)F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) indicated markedly suppressed glucose metabolism in the left thalamus but not markedly in the striatum. At that time the neurologic examination demonstrated complete left hemiparesis, severe rigidity of the right upper extremity, and inability to move the right hand and fingers. Levodopa at 300-600 mg/day improved movement of the fingers, decreased the rigidity in the extremity, and lessened the metabolic abnormality. Diminished metabolism in the left thalamus may have contributed to symptoms. The case illustrates the usefulness of PET in disclosing symptom causing abnormalities not detected by magnetic resonance imaging.

Gait disturbance in patients with low pressure hydrocephalus.

Using criteria of the classification recently described by Nutt et al., we examined gait disorder in five patients with normal pressure hydrocephalus (NPH). Their cerebrospinal fluid (CSF) pressures were in the normal range, and trials of CSF removal produced temporary improvement of symptoms. Surgical procedures to relieve hydrocephalus improved gait disorders in all patients. No patient showed spasticity, sensory ataxia, cerebellar ataxia, extrapyramidal signs, or limb apraxia. All walked slowly with a wide base and a short stride. The arm swing normally associated with walking was preserved. In standing, patients were unsteady and fell easily when pushed. Four patients showed hesitation in initiating walking and in turning. These clinical features fit Nutt's criteria for frontal gait disorder and frontal disequilibrium. Unlike findings in Parkinson's disease, where similar gait disorders may occur, other extrapyramidal signs, Myerson's sign, and upper limb dysfunction were absent in NPH, and arm swing while walking was preserved. We suspect that ventricular dilatation disturbs neuronal connections between the supplementary motor area and the globus pallidus in NPH patients.

Magnetic resonance imaging in cases with encephalopathy secondary to immunosuppressive agents.

The neurotoxic effects of immunosuppressive agents used after transplantation are well known. In most cases a decrease in drug dosage results in resolution of the neurotoxicity. At early stages in the post-transplantation clinical course, neurotoxicity and other complications such as infectious disease, encephalopathy and seizures are sometimes difficult to diagnose with neuroimaging. Recently, diffusion weighted imaging (DWI) has been used in patients with ischemic disease, mitochondrial myopathy, encephalopathy and demyelinating disease. We examined the magnetic resonance images (MRI), including DWI and fluid attenuated inversion recovery image (FLAIR), in three cases of post-transplantation neurological complication: two cases of neurotoxicity and a case of acute disseminated encephalomyelitis (ADEM). Hyper-intense lesions representing neurotoxicity were seen on FLAIR but not on DWI in two cases with neurotoxicity induced by an immunosuppressive agent. In ADEM, hyper-intense lesions were seen on both FLAIR and DWI. Neurotoxicity due to the immunosuppressive agent showed a favorable outcome, although the hyper-intense lesions temporally presented on FLAIR. In the state after transplantation, hyper-intense lesions on FLAIR and DWI represented in the brain from the initial stage, we might be care of other severe complications but for neurotoxicity.

Intradural, extramedullary spinal Ewing's sarcoma in childhood.

We describe an 11 year old girl with progressive paraparesis from a spinal tumour. Magnetic resonance imaging showed an intradural, extramedullary mass extending from the C7 level to T1. Neither osteolytic nor osteosclerotic changes were seen in the vertebral bodies. Extraskeletal Ewing's sarcoma was diagnosed histopathologically.

[A case of pineoblastoma primary presenting a pineal hemorrhage causing obstructive hydrocephalus].

A 9-year-old female suddenly developed headache and nausea. Computed tomography (CT) revealed pineal mass lesion and obstructive hydrocephalus. One week after the onset, hydrocephalus spontaneously resolved. Magnetic resonance imaging (MRI) revealed that the mass was a subacute hematoma and that hydrocephalus had improved. Sequential MRI 4 months later revealed an enhanced lesion in the pineal region. Total removal of the tumor by the occipital transtentorial approach established the histopathological diagnosis of pineoblastoma.

[A case of traumatic sinus pericranii].

Sinus pericranii is a rare vascular anomaly involving an abnormal communication between the extracranial and intracranial circulations. A 33-year-old woman presented with a soft tissue mass at the left frontal region. It was associated with head trauma when she was 12-year-old. The mass had gradually grown and become painful for 20 years. She underwent surgical resection of the mass successfully. This report discusses traumatic sinus pericranii.

[A lesion diagnosed by MRI in a case of transient global amnesia].

Transient global amnesia(TGA) had been recognized as a disease without abnormal findings on neuroimaging before magnetic resonance(MRI) imaging was practicable. Recently, abnormal findings on MRI reported in cases of TGA. We here reported a case of TGA showing a transient abnormal intensity in left hippocampus on MRI diffusion-weighted image. A 52-year-old man suddenly became to unable to keep his recent memory without histories of trauma or epilepsy. He showed no abnormal neurologic findings excepting for the recent memory. MRI performed within an hour after onset demonstrated no abnormality on T1- and T2-weighted images. Diffusion-weighted image (b = 1,000) showed hyperintensity in the left medial temporal lobe, and the apparent diffusion coefficient(ADC) in this region was lower(72.8 cm2/s) than that in the contralateral region(94.4 cm2/s). TGA was completely resolved 17 hours after onset.