Biplane fluoroscopy-guided percutaneous spinal cord stimulation

OBJECTIVE

Fluoroscopy is useful for spinal cord stimulation (SCS) lead placement. We employed biplane fluoroscopy for SCS lead placement. In this study, we sought to confirm the validity of using biplane fluoroscopy for SCS lead placement and to establish whether biplane fluoroscopy safely reduces the duration of surgery.

METHODS

Clinical data were retrospectively collected from the medical records of patients who underwent SCS lead placement under local anesthesia from 2015 to 2022. The duration of the surgical phase and the total radiation exposure time per case were recorded.

RESULTS

Forty-six patients underwent percutaneous SCS lead implantation. Recording was completed in 41 cases: one lead was placed in 13 cases and two leads were placed in 28 cases. Monoplane and biplane fluoroscopy was used in 15 and 26 patients, respectively. Although the type of fluoroscopy did not significantly affect the mean duration of the surgical phase in patients in which one lead was placed, biplane fluoroscopy was associated with a significant reduction in the mean duration of the surgical phase in patients that underwent placement of two leads (P=0.002). No significant differences in the total radiation exposure time were observed between patients in the monoplane and biplane fluoroscopy groups that were implanted with one (P=0.21) or two leads (P=0.62).

CONCLUSIONS

The use of biplane fluoroscopy reduced the duration of surgery necessary for the placement of two SCS leads. Biplane fluoroscopy represents a practical and safe adjustment to the current practice of SCS lead implantation.

Symptomatic epidural haematoma after cervical laminoplasty: a report of three cases

Symptomatic epidural haematoma after cervical laminoplasty is rare. We report 3 patients who required emergency evacuation of an epidural haematoma. Timely diagnosis and removal of the haematoma is important to prevent neurological deficits. The causative factors in these patients were preoperative coagulopathy, hypertension, and the malfunction of a closed-suction drain.

Usefulness of intraoperative magnetic resonance imaging for glioma surgery

BACKGROUND

Radical resection of gliomas can increase patient's survival. There is known concern, however, that aggressive tumour removal can result in neurological morbidity. The objective of the present study was to evaluate the usefulness of low magnetic field strength (0.3 Tesla) open intraoperative magnetic resonance imaging (iMRI) for complete resection of glioma with emphasis on functional outcome.

METHODS

From 2000 to 2004, 96 patients with intracranial gliomas underwent tumour resection with the use of iMRI in Tokyo Women's Medical University. There were 50 men and 46 women; mean age was 39 years. Tumour volume varied from 1.2 ml to 198 ml (median: 36.5 mL). Resection rate and postoperative neurological status were compared between control group (46 cases, operated on during the initial period after installation of iMRI), and study group (50 most recent cases, in whom surgery was done using established treatment algorithm and improved image quality).

FINDINGS

Overall, mean resection rate was 93%, and medial residual tumour volume was 0.17 ml. Total tumour removal was achieved in 44 cases (46%). Compared to control group, resection rate in the study group was significantly higher (91%, vs. 95%; P < 0.05), whereas residual tumour volume was significantly smaller (1.7 mL vs. 0.025 mL; P < 0.001). Nine patients in the control group (20%) and 24 in the study group (48%) experienced temporary postoperative neurological deterioration (P < 0.01), however, the rate of permanent morbidity evaluated 3 months after surgery did not differ significantly between the groups investigated (13% vs. 14%).

CONCLUSIONS

Use of iMRI during surgery for intracranial gliomas permits to attain aggressive tumour resection with good functional outcome. Nevertheless, surgical experience with the iMRI system, establishment of treatment algorithm, and improvement of image quality are of paramount importance for optimal results.

Bone cancer increases transient receptor potential vanilloid subfamily 1 expression within distinct subpopulations of dorsal root ganglion neurons

Bone cancer pain has a strong impact on the quality of life of patients but is difficult to treat. Therefore, the mechanisms of bone cancer pain require elucidation for the purpose of development of new therapeutics. A recent study showed that activation of transient receptor potential vanilloid subfamily 1 (TRPV1) was involved in bone cancer pain. In this study, we re-evaluated the analgesic effects of pharmacological blockade of TRPV1 using the potent TRPV1 antagonist 5-iodoresiniferatoxin (I-RTX) and examined whether bone cancer can change TRPV1 expression and distribution in the primary sensory neurons in a mouse model of bone cancer pain. Implantation of osteosarcoma into the femur induced ongoing and movement-evoked bone cancer-related pain behaviors. These behaviors were significantly reduced by i.p. administration of I-RTX, compared with vehicle. Western blot and reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that TRPV1 level was significantly increased in dorsal root ganglions (DRGs) ipsilateral to sarcoma implantation. Immunohistochemical analysis showed that implantation of osteosarcoma induced not only an increase in the percentage of TRPV1-positive neurons among DRG neurons (24.3+/-1.3% in sham mice and 31.2+/-1.3% in mice with osteosarcoma implantation, P<0.05) but also an overall shift in the distribution of area of profiles to the right. Colocalization study showed that the percentages of colocalization of TRPV1 with neurofilament 200 kD (NF200) and calcitonin gene-related peptide (CGRP) but not isolectin B4 (IB4) among DRG neurons in mice with osteosarcoma implantation were increased compared with those in sham mice (from 0.8+/-0.1% to 2.1+/-0.3% for TRPV1 and NF200 and from 21.1+/-1.3% to 26.5+/-0.2% for TRPV1 and CGRP). In conclusion, TRPV1 activation plays a critical role in the generation of bone cancer pain, and bone cancer increases TRPV1 expression within distinct subpopulation of DRG neurons. These findings may lead to novel strategies for the treatment of bone cancer pain.

Immunohistochemical analysis of acid-sensing ion channel 2 expression in rat dorsal root ganglion and effects of axotomy

Several studies have suggested that acid-sensing ion channel 2 (ASIC2) plays a role in mechanoperception and acid sensing in the peripheral nervous system. We examined the expression and distribution of ASIC2 in the rat dorsal root ganglion, the co-localization of ASIC2 with tropomyosin-related kinase (trk) receptors, and the effects of axotomy on ASIC2 expression. ASIC2 immunoreactivity was observed in both neurons and satellite cells. ASIC2-positive neurons accounted for 16.5 +/- 2.4% of the total neurons in normal dorsal root ganglion. Most ASIC2-positive neurons were medium-to-large neurons and were labeled with neurofilament 200 kD (NF200). Within these neurons, ASIC2 was not evenly distributed throughout the cytoplasm, but rather was accumulated prominently in the cytoplasm adjacent to the axon hillock and axonal process. We next examined the co-localization of ASIC2 with trk receptors. trkA was expressed in few ASIC2-positive neurons, and trkB and trkC were observed in 85.2% and 53.4% of ASIC2-positive neurons, respectively, while only 6.9% of ASIC2-positive neurons were co-localized with trkC alone. Peripheral axotomy markedly reduced ASIC2 expression in the axotomized dorsal root ganglion neurons. On the other hand, intense ASIC2 staining was observed in satellite cells. These results show that ASIC2 is expressed in the distinct neurochemical population of sensory neurons as well as satellite cells, and that peripheral axotomy induced marked reductions in ASIC2 in neurons.

Acute hemispheric swelling associated with thin subdural hematomas: pathophysiology of repetitive head injury in sports

INTRODUCTION

The most common head injury in sports is concussion, and repeated concussions occurring within a short period occasionally can be fatal. Acute subdural hematoma is the most common severe head injury and can be associated with severe neurologic disability and death in sports. We investigated severe brain damage resulting from repetitive head injury in sports, and evaluated the pathophysiology of sports-related repetitive injury.

METHODS

We reviewed the literature containing detailed descriptions of repetitive severe sports-related head injury. In total, 18 cases were analyzed with regard to age, gender, type of sports, symptoms before second injury, and pathology of brain CT scans.

RESULTS

The majority of cases involved young males aged 16 to 23 years old, who sustained a second head injury before symptoms from the first head injury had resolved. Ten of 15 cases did not suffer loss of consciousness at insult. Eight cases were confirmed on brain CT scans after the second injury, and all 8 cases revealed brain swelling associated with a thin subdural hematoma.

CONCLUSIONS

Second impact syndrome is thought to occur because of loss of autoregulation of cerebral blood flow, leading to vascular engorgement, increased intracranial pressure, and eventual herniation. Our investigation suggests that the existence of subdural hematoma is a major cause of brain swelling following sports-related, repetitive head injury.

Matrix metalloproteinase-9 is associated with blood-brain barrier opening and brain edema formation after cortical contusion in rats

Matrix metalloproteinases (MMPs) are associated with blood-brain opening and may be involved in the pathophysiology of acute brain injury. Previous research demonstrated that knockout mice deficient in MMP-9 subjected to transient focal cerebral ischemia had reduced blood-brain barrier (BBB) disruption and attenuated cerebral infarction. In this study, we examined MMP-9 up-regulation, BBB disruption, and brain edema formation after cortical impact injury in rats. Cortical contusion was induced by controlled cortical impact. Animals were sacrificed at intervals after injury. MMP up-regulation was assessed by gelatin zymography, and BBB integrity was evaluated using Evans blue dye with a spectrophotometric assay. Brain water content was measured by comparing wet and dry weights of each hemisphere as an indicator of brain edema. Zymograms showed elevated MMP-9 as early as at 3 hours after injury, reaching a maximum at 18 hours. Peak levels of BBB disruption occurred 6 hours after injury. Brain edema became progressively more severe, peaking 24 hours after injury. Compared to control group, treatment with MMP-inhibitor GM6001 significantly reduced BBB disruption 6 hours and brain water content (85.9 +/- 0.5% vs. 82.6 +/- 0.3%; p < 0.05) 24 hours after injury. These findings suggest that MMP-9 may contribute to BBB disturbance and subsequent brain edema after traumatic brain injury.

Surgical management of early massive edema caused by cerebral contusion in head trauma patients

Early massive edema caused by severe cerebral contusion results in elevation of intracranial pressure (ICP) and clinical deterioration within 24-72 hours post-trauma. Previous studies indicate that cells in the central area of the contusion undergo shrinkage, disintegration, and homogenization, whereas cellular swelling is predominant in the peripheral area, suggesting that early massive edema is attributable to high osmolality within necrotic brain tissue and may generate an osmotic potential across central and peripheral areas. We analyzed the effects of surgical excision of necrotic brain tissue in 182 patients with cerebral contusion registered with Japan Neurotrauma Data Bank; 121 patients (66%; Group I) were treated conservatively, and 61 (34%; Group II) were treated surgically. Most Group II cases (90%) underwent complete excision of necrotic brain tissue and evacuation of clots. Group I demonstrated higher mortality at 6 months post-trauma compared to Group II (48%) vs. 23%; p = 0.0001; n = 182). Striking differences were observed in patients scoring 9 or more on Glasgow Coma Scale at admission (56% vs. 17%); p = 0.017; n = 45) and demonstrated "talk-and-deteriorate" (64% vs. 22%: p = 0.026; n = 29), supporting our hypothesis that early massive edema is caused by cerebral contusion accompanied by necrotic brain tissue, indicating that surgical excision of necrotic brain tissue provides satisfactory control of progressive elevation in ICP and clinical deterioration in many cases.

Endothelin-1 enhances capsaicin-evoked intracellular Ca2+ response via activation of endothelin a receptor in a protein kinase Cε-dependent manner in dorsal root ganglion neurons

Increasing evidence indicates that endothelin-1 has a role for peripheral nociceptive signaling in animals and humans. However, the mechanisms of the nociceptive effects of endothelin-1 have not been fully understood. The current study investigated the effects of endothelin-1 on the capsaicin-evoked intracellular Ca2+ response of cultured adult mice dorsal root ganglion neurons. Dorsal root ganglia were harvested from adult male C57B6N mice and were cultured. With a digital image analysis system, we detected the [Ca2+]i image of cultured dorsal root ganglion cells after loading with Fura-2 acetoxymethyl. In addition, co-localization of protein kinase Cepsilon with transient receptor potential V1 and the translocation of protein kinase Cepsilon were investigated using immunohistochemical methods. Endothelin-1 (10 nM) enhanced an increase in [Ca2+]i by capsaicin (10 nM) from 87.6+/-11.6 nM to 414.8+/-62.3 nM (71 of 156 neurons). The inhibition of endothelin A receptor (BQ-123) significantly suppressed the enhancing effect of endothelin-1. In addition, a nonselective protein kinase C inhibitor (bisindolylmaleimide I) significantly suppressed the enhancing effect of endothelin-1. A myristoyl-tagged membrane-permeant-protein kinase Cepsilon V1-2 inhibitory peptide also significantly suppressed the enhancing effect of endothelin-1. In the immunocytochemical study, protein kinase Cepsilon immunoreactivity was found in most of transient receptor potential V1-positive neurons. After endothelin-1 application, protein kinase Cepsilon immunoreactivity was observed to be translocated from the cytosol to the cell membrane in transient receptor potential V1-positive neurons. Our results indicate that endothelin-1 enhances the response of dorsal root ganglion neurons to capsaicin in a protein kinase Cepsilon-dependent manner. Our findings may lead to a new strategy to treat pain associated with endothelin-1.

Experimental model for investigating hyponatremia after subarachnoid hemorrhage in rats

Hyponatremia is a common complication in patients with aneurysmal subarachnoid hemorrhage (SAH). Such patient demonstrates excessive natriuresis and an increased risk of symptomatic cerebral vasospasm. However, the precise mechanisms underlying SAH induced hyponatremia remain unclear. In the present study, in order to establish an experimental model of hyponatremia following SAH, we induced SAH in rats, and evaluated the serum sodium (Na) levels, Na excretion and physiological parameters. Twenty-four male Wistar rats were used. SAH was induced by an endovascular puncture method. The mean arterial pressure (MAP), intracranial pressure (ICP), and cerebral blood flow (CBF) were monitored continuously. The urine was collected cumulatively for 12 hours after SAH, and the urine Na concentration was determined with a spectrophotometer. The serum Na levels were measured at 12 hrs, 2 and 4 days following the SAH induction. The mean (+/- standard deviation) baseline ICP was 3.5 +/- 2.6 mmHg, and increased to 67.4 +/- 17.6 mmHg immediately following induction of SAH. CBF decreased rapidly, and then gradually recovered to 70-80% of baseline. The urine volume and total Na excretion were significantly increased in comparison to those of the sham (P < 0.05). The serum Na level was significantly decreased at 4 days following SAH (P < 0.05). The present results demonstrated for the first time that rats with SAH exhibited excessive natriuresis. The endovascular puncture model is suitable for investigating hyponatremia that occurs concomitantly with natriuresis and diuresis after SAH.

Extravascular application of an intravascular ultrasound (IVUS) catheter during carotid endarterectomy to verify distal ends of stenotic lesions

BACKGROUND

Intravascular ultrasound (IVUS) has been developed initially for intravascular imaging of coronary arteries to investigate vascular structures. We applied the IVUS catheter extravascularly to the cervical carotid arteries to obtain intra-operative ultrasound images during carotid endarterectomy (CEA). Intra-operative assessments of the distal ends of the stenotic lesions as well as pathological vascular structures are important, not only for exposing the lesions sufficiently but also for placing the shunt system safely.

METHOD

An IVUS catheter (3.2 French/30 MHz) was intra-operatively applied close to the outer surface of the cervical carotid arteries during CEA. Ultrasound transection vascular images were obtained in 33 consecutive patients (30 males and 3 females) with a mean age of 66.5 years.

FINDINGS

In 32 of 33 cases, extravascular application of IVUS catheter before making arteriotomies correctly depicted the distal ends of the internal carotid artery (ICA) stenotic lesions as a thin layer of vascular wall [0.64 +/- 0.16 mm (mean +/- SD) compared with 1.66 +/- 0.42 mm for carotid plaque] with intravascular blood flow. Based on the IVUS findings, we were able to adequately expose the normal ICA portion distal to the stenotic lesion before making the arteriotomy even in cases with stenotic lesions at very high positions, and to insert shunts safely. Furthermore, the properties of lesions and blood flow were also verified. However, it was difficult to examine the far vascular wall.

CONCLUSIONS

Extravascular application of IVUS catheter is efficient for intra-operative evaluation of the distal end of the stenotic lesion especially in cases with stenotic lesions at very high positions and cases in whom pre-operative angiograms did not clearly demonstrate the distal end. The findings also demonstrate the properties of lesions and completeness of CEA.

Metabolic derangements in interstitial brain edema with preserved blood flow: selective vulnerability of the hippocampal CA3 region in rat hydrocephalus

Hydrocephalus induces interstitial brain edema, which causes neurological deficits, even if the intracranial pressure is maintained within the normal range, and the cerebral blood flow (CBF) does not decline to an ischemic level. The precise mechanisms underlying such edema-induced neuronal dysfunction remain unclear. In the present study, in an attempt to elucidate the metabolic derangements in brain tissue with interstitial edema, we evaluated the changes in CBF and oxidative/glucose metabolism using a rat model of kaolin-induced hydrocephalus. Hydrocephalus was produced in male Wistar rats by intrathecal injection of 0.1 ml aluminum silicate suspension (200 mg/ml) via the cisterna magna. CBF was determined by 14[C]-iodoantipyrine autoradiography. Oxidative metabolism was evaluated by cytochrome oxidase (CYO) histochemistry, and glucose metabolism by hexokinase (HK) histochemistry. CBF declined with the development of hydrocephalus, but did not reach an ischemic level. The CYO activity was diffusely depressed in both the cortex and hippocampus. The HK activity was preserved at the early stage of hydrocephalus. At the advanced stage, the HK activity was reduced in the hippocampal CA3 region first, and diffusely thereafter. In conclusion, interstitial brain edema impairs oxidative metabolism even at the early stage of hydrocephalus, and shifts the metabolism to anaerobic glycolysis despite a preserved CBF. Impairment of glucose metabolism was first observed in the CA3 region, suggesting that the CA3 is metabolically vulnerable, and CA3 dysfunction may contribute to the memory deficits seen in hydrocephalus.

Pneumocephalus following an epidural blood patch

Pneumocephalus is a rare complication of epidural block. We report a case of pneumocephalus complicating an epidural blood patch performed 3 days after unintentional dural puncture. Pneumocephalus may occur during an epidural blood patch procedure, even if the epidural needle tip is within the epidural space.

Mechanisms of the mass effect of cerebral contusion: ICP monitoring and diffusion MRI study

OBJECTIVE

Cerebral contusion is sometimes associated with a non-hemorrhagic mass effect which progresses rapidly within 12-48 hours post-trauma. In order to determine the mechanisms underlying such a mass effect, we analyzed data obtained from ICP monitoring and diffusion MRI in a total of 38 patients with cerebral contusion.

METHODS

Diffusion imaging and ADC mapping were performed employing 1.5 T echo planar MRI. ADC values were expressed as a ratio relative to the values of intact brain areas.

RESULTS

In 6 patients, ICP became uncontrollable medically and surgical resection of the contused brain tissue was eventually performed. Within 24 hours post-trauma, diffusion images revealed a low intensity core and a high intensity rim in the contusion. The ADC ratio increased in the central area (1.13 +/- 0.21) and decreased in the peripheral area (0.67 +/- 0.14). A crescent-shaped zone of very high ADC ratio (1.45 +/- 0.14) was observed at the border between these two areas during the period of 24-48 hours.

CONCLUSIONS

It appears that the capacitance of edema fluid accumulation is elevated by cellular disintegration in the central area, whereas the resistance to edema fluid propagation is elevated by cellular swelling in the peripheral area. We suggest that such events facilitate extracellular edema fluid accumulation within contused brain tissue and contribute, together with cellular swelling itself, to the non-hemorrhagic mass effect of cerebral contusion.

Edema fluid accumulation within necrotic brain tissue as a cause of the mass effect of cerebral contusion in head trauma patients

The early massive edema caused by severe cerebral contusion results in progressive intracranial pressure (ICP) elevation and clinical deterioration within 24-72 hours post-trauma. Surgical excision of the necrotic brain tissue represents the only therapy, which can provide satisfactory control of the elevated ICP and clinical deterioration. In order to elucidate the mechanisms underlying the early massive edema, we have carried out a series of detailed clinical studies. Diffusion magnetic resonance (MR) imaging and apparent diffusion co-efficient (ADC) mapping suggest that cells in the central area of contusion undergo shrinkage, disintegration and homogenization, whereas cellular swelling is predominant in the peripheral area during the period of 24-72 hours post-trauma. The ADC values in the central and peripheral areas are maximally dissociated during this period. A large amount of edema fluid accumulates within the necrotic brain tissue of the central area beginning at approximately 24 hours post-trauma. We have found that fluid-blood interface formation within the central area does not represent an uncommon finding in various neuroimaging examinations of cerebral contusions, indicating layering of red blood cells within the necrotic brain tissue accumulating voluminous edema fluid. Intravenous slow infusion of gadolinium-DTPA and delayed MR imaging revealed that the central area of contusion can be enhanced at 24-48 hours post-trauma. implying that water supply from the blood vessels is not completely interrupted. Necrotic brain tissue sampled from the central area of contusion during surgery demonstrates a very high osmolality. It appears that the capacitance for edema fluid accumulation increases in the central area, whereas cellular swelling in the peripheral area elevates the resistance for edema fluid propagation. Combination of these circumstances may facilitate edema fluid accumulation in the central area. We also suggest that the dissociation of ADC values and high osmolality within the necrotic brain tissue may generate an osmotic potential across the central and peripheral areas and contribute to the early massive edema caused by cerebral contusion.

Ultra-early study of edema formation in cerebral contusion using diffusion MRI and ADC mapping

OBJECTIVE

Our previous studies have reported that heterogeneous mechanisms exist in early edema formation in cerebral contusion, and cytotoxic edema plays an important role within 48 hours post-trauma. It is remains unclear, when edema begins to develop following injury. In order to determine the time course of edema development, diffusion imaging and ADC (apparent diffusion co-efficient) mapping was performed in 10 patients within 24 hours post-trauma with cerebral contusion.

METHODS

Diffusion imaging and ADC mapping were performed employing 1.0 T echo planar MRI. ADC values were indicated as a ration relative to the values of intact brain areas.

RESULTS

Within 3 hours post-trauma, diffusion MRI showed no remarkable changes, and the ADC values were within normal limit (ADC ratio (=contused/normal brain) = 1.00 +/- 0.21, (mean +/- SD)). At 6 hours post-trauma, diffusion images demonstrated a low intensity core in the contusion proper and a high intensity rim in the peripheral area of contusion. The ADC value increased in the contusion proper (ADC ratio = 1.26 +/- 0.13) and decreased in the peripheral area (ADC ratio = 0.58 +/- 0.19).

CONCLUSIONS

These findings indicated that early cellular swelling in the peripheral area of contusion begins within 6 hours following injury. This delayed occurrence of contusion-induced cellular swelling suggests that the CBF does not decrease to ischemic level immediately following injury.

Flexible endoscope-assisted endonasal transsphenoidal surgery for pituitary tumors

We have performed rigid endoscope-assisted endonasal transsphenoidal microsurgeries for pituitary tumors in 230 patients. Recently, we further introduced the use of a flexible endoscope to inspect the tumor bed and suprasellar structures more extensively. We report our experience with the flexible endoscope in endonasal transsphenoidal surgery for pituitary tumors. The endoscopes were used to complement the microscope in visualization. The flexible endoscopes were used in 34 recent cases with suprasellar and/or lateral tumor extension. During or after removal of the main tumor bulk, the flexible endoscope together with a rigid endoscope was used to inspect the tumor cavity, especially at the blind spot of the microscope. Despite limited resolving power, in all the 34 cases the flexible endoscope was a highly efficient tool permitting extensive visualization of almost the whole surgical area, even in narrow surgical fields and spaces not visible with an operating microscope or a rigid endoscope, and allowing continuous change of viewing angle. The residual tumor situated laterally or in the suprasellar areas that could not be reached and was impossible to remove by a rigid endoscope could be dissected and extirpated under a flexible endoscope using grasping forceps in 5 patients with pituitary adenoma and all the craniopharyngioma cases. The flexible endoscope may be more efficient in the lateral and suprasellar areas than the rigid endoscope in compensating for the narrow surgical field in endonasal pituitary surgery, despite its limited resolving power. Surgeons should make the best use of the advantages of each instrument.

New possibilities for stereotaxis. Information-guided stereotaxis

Information-guided stereotaxis, assisted by visualization of medical information, will become the next generation of neurosurgical systems. We performed 76 open MRI surgeries at Tokyo Women's Medical University between March 3, 2000 and April 12, 2001. Of them, comparisons of pre- and post-operative MR images for malignant gliomas in 21 cases revealed an average resection rate of 90.3% (the maximum 100%, the minimum 55%). In this article we describe real time updated navigation, augmented reality navigation, three-dimensional navigation, chemical navigation, information-guided navigation system (High definition visual Computer Aided Surgery System: HivisCAS), and open MRI-guided surgery that we are developing.

Ectopic clival craniopharyngioma

Ectopic craniopharyngioma is a rare entity. The authors present a very rare case of an ectopic clival craniopharyngioma completely separate from the sella turcica.A 44-year old woman presented with abducens palsy. A MR imaging study and a CT scan revealed a cystic clival lesion separate from the sella turcica. Surgical resection was performed successfully with flexible endoscope-assisted procedure using an endonasal transsphenoidal approach. No evidence of involvement of the sellar region was found according to radiological, intra-operative, and clinical findings.A review of the literature revealed no other such cases. The discussion includes the formation of craniopharyngioma from the ectopic Rathke's pouch remnants and the surgical approach for clival lesions. We believe that our approach provides good results with minimal invasiveness for some clival lesions.

Deep brain stimulation therapy for a persistent vegetative state

Twenty cases of a persistent vegetative state (PVS) caused by various kinds of brain damage were neurologically and electrophysiologically evaluated at 3 months after persistence of the PVS, and were treated by deep brain stimulation (DBS) therapy. The stimulation sites were the mesencephalic reticular formation (2 cases) and CM-pf complex (18 cases). Seven of the patients emerged from the PVS, and became able to obey verbal commands. However, they remained in a bedridden state. These 7 cases revealed a desynchronization or slight desynchronization pattern on continuous EEG frequency analysis. The Vth wave of ABR and N20 of SEP could be recorded even with a prolonged latency, and the pain-related P250 was recorded with an amplitude of over 7 microV. We conclude that chronic DBS therapy may be useful for allowing the patient to emerge from a PVS, if the candidates are selected according to the neurophysiological criteria. In view of the severely disabled state of the patients who emerged from the PVS, a special rehabilitation program which includes neurostimulation therapy may be necessary for treatment of the PVS.

Control of post-stroke movement disorders using chronic motor cortex stimulation

The effects of motor cortex (MC) stimulation on post-stroke movement disorders were analyzed in 50 patients. These individuals either underwent MC stimulation primarily for the purpose of controlling their post-stroke involuntary movements (n = 8) or underwent MC stimulation for the purpose of controlling their post-stroke central pain (n = 42). In the latter patients, the effects of MC stimulation on co-existent involuntary or voluntary movement disorders were analyzed retrospectively. Good control of involuntary movements was observed in 2 of 3 patients with hemichoreo-athetosis, 2 of 2 patients with distal resting or action tremor, and 1 of 3 patients with proximal postural tremor. Subjective improvements in motor performance were reported by 8 patients who had mild motor weakness, and the effects appeared to be attributable to attenuation of rigidity. We consider that these findings justify further clinical studies on MC stimulation for the control of post-stroke movement disorders.

Infantile gliosarcoma: a case and a review of the literature

INTRODUCTION

Gliosarcoma in infant is a very rare entity.

CASE REPORT

The authors present a case of gliosarcoma in a 23-month-old boy. The patient was admitted to our hospital with persistent headache and frequent vomiting. MR imaging demonstrated a large frontal well-circumscribed lesion with a heterogeneous gadolinium enhancement. Although macroscopically the tumor was totally extirpated, the boy died of rapid tumor regrowth 2 months after surgery. The surgical specimens obtained from the tumor showed an admixture of two distinctive neoplastic tissues. One was a malignant mesenchymal feature. Its fibrosarcomatous nature was characterized by spindle-shaped cells with fine fibers that were deeply stained in silver preparations for reticulin. The other was gliomatous tissue forming islands surrounded by the sarcomatous tissues. Its glioblastomatous nature was obvious, as it was characterized by endothelial proliferation and perinecrotic pseudopalisading. Both tissues were histologically malignant, as evidenced by mitotic figure, high cellularity, atypical features, and variability.

DISCUSSION

The literature concerning gliosarcomatous tumors is reviewed, and pathological and clinical features of the tumor are briefly discussed.

Expression of cyclin kinase inhibitor p21/WAF1 protein in pituitary adenomas: correlations with endocrine activity, but not cell proliferation

p21/WAF1 blocks cell cycle progression through inhibition of cyclin/cyclin-dependent kinases (cdks) complexes and, simultaneously, has been associated with cell cycle exit and the process of differentiation. In this series, the expression of p21/WAF1 was assessed immunohistochemically in 47 cases of pituitary adenomas in relation to endocrine activity and cell proliferation. To evaluate cell proliferation, a monoclonal antibody, MIB-1, against Ki-67 antigen was used in all of the available cases. The study revealed positive p21/WAF1 staining in 24 cases of 26 functioning parenchymas, whereas 14 cases of 21 non-functioning parenchymas stained negative. The MIB-1 index ranged from less than 1% to 5.1% (mean: less than 1.7%) in functioning adenomas, and from less than 1% to 3.6% (mean: less than 1.6%) in non-functioning adenomas. Regardless of endocrine activity, p21/WAF1 positivity did not correlate with the MIB-1 index. Double staining techniques revealed the co-expression of p21/WAF1/GH or p21/WAF1/PRL in functioning adenomas. In 22 cases of p21/WAF1-positive functioning adenomas, p21/WAF1 immunoreactivity was seen in the cytoplasma as well as nuclei. These results indicate that in pituitary adenomas, p21/WAF1 expression is associated with endocrine activity, but not with cell proliferation. Taken together with recent findings demonstrating that cytoplasmic p21/WAF1 acts as an inhibitor of apoptosis, it is possible that pituitary adenomas expressing cytoplasmic p21/WAF1 have resistance against DNA-damaging agents such as ionizing radiation.

Involvement of capsaicin-sensitive fibers in spinal NMDA-induced glutamate release

The activation of spinal NMDA receptors can evoke glutamate release through the production of nitric oxide (NO) within the spinal cord, resulting in pain-relating behavior. In this study, we investigated the involvement of capsaicin-sensitive primary afferents in this phenomenon using in vivo intrathecal microdialysis. Intrathecal NMDA perfusion evoked increases in the concentrations of NO metabolises and glutamate and in pain-related behavior in both neonatal capsaicin and vehicle-treated rats. Although the degrees of increase in NO metabolises in capsaicin- and vehicle-treated rats were not significantly different, capsaicin-treated rats showed significantly smaller increases in glutamate concentration and pain-related behavior than did vehicle-treated rats. Our results showed that glutamate release from capsaicin-sensitive primary afferent terminals is involved in spinal NMDA-induced pain.

Peripheral nitric oxide in carrageenan-induced inflammation

Recent studies have suggested that nitric oxide (NO) peripherally produced by different nitric oxide synthase (NOS) isoforms contributes to edema formation and development of hyperalgesia. The present study was designed to examine the effects of NOS isoforms on NO release in carrageenan-induced inflammation at various time points. A microdialysis probe was implanted subcutaneously into the glabrous skin of hindpaws of Sprague-Dawley rats under pentobarbital anesthesia. After sample collection to obtain the basal level of the total amount of nitrite and nitrate (NO2-/NO3-), modified Ringer solution, a non-selective NOS inhibitor, NG monomethyl-L-arginine acetate (L-NMMA), or an iNOS inhibitor, aminoguanidine hemisulfate (AG) was perfused through the microdialysis probe. 2 mg of carrageenan was injected into the plantar surface of the probe-implanted hindpaw. Carrageenan was also injected in rats that had undergone sciatic nerve sectioning. Carrageenan significantly increased the dialysate concentrations of NO2-/NO3- for more than 8 h. L-NMMA suppressed the carrageenan-induced increase in NO2-/NO3- concentration. Although AG did not suppress the increase in NO2-/NO3- for the first 2 h after carrageenan injection, significant suppression of the increase in NO2-/NO3- was observed from 2.5 h after carrageenan injection. In the rats in which the sciatic nerves had been denervated, the increases in concentrations of NO2-/NO3- were completely suppressed up to 3 h and partially suppressed 4.5-8 h after carrageenan injection. The results of the current study show that carrageenan induces peripheral release of NO, the production of which is mediated by nNOS in the early phase and by both nNOS and iNOS in the late phase of carrageenan-induced inflammation.

Heterogeneous mechanisms of early edema formation in cerebral contusion: diffusion MRI and ADC mapping study

Severe cerebral contusion is sometimes associated with early edema formation within 24-48 hours post-trauma, and this frequently results in progressive ICP elevation and clinical deterioration. To investigate the underlying mechanisms of such severe contusion edema, diffusion imaging and ADC mapping were performed in 20 patients with cerebral contusion, employing 1.5 T echo planar MRI. Within 24 hours post-trauma, the diffusion images demonstrated a low intensity core in the central area and a high intensity rim in the peripheral area of contusion. The ADC value increased in the central area (ADC ratio (contusion/normal brain) = 1.13 +/- 0.13) and decreased in the peripheral area (ADC ratio = 0.83 +/- 0.13). This suggested that intra- and extracellular components underwent disintegration and homogenization within the central area, whereas cellular swelling was predominant in the peripheral area. A crescent-shaped zone of very high ADC value (ADC ratio = 1.38-1.61) was observed at the border between these two areas during the period of 24-48 hours post-trauma in some cases, apparently indicating that edema fluid was accumulated within a space formed by homogenization. The ADC values in the peripheral area shifted to an increase after 48-72 hours post-trauma. These findings imply that multiple mechanisms operate in early edema formation in cerebral contusion. It appears that the capacity for edema fluid accumulation increases in the central area and resistance for edema fluid propagation is elevated by cellular swelling in the peripheral area. We suggest that a combination of such events facilitates edema fluid accumulation in the central area and contributes, together with the cellular swelling in the peripheral area, to the mass effect of contusion edema. Diffusion MRI and ADC mapping represent powerful tools for investigating spatially as well as temporally heterogeneous mechanisms of contusion edema.

Microglial signaling by amyloid beta protein through mitogen-activated protein kinase mediating phosphorylation of MARCKS

Myristoylated alanine-rich C kinase substrate (MARCKS), an acidic protein associated with cell motility and phagocytosis, is activated upon phosphorylation by protein kinase C (PKC) and proline-directed protein kinases. In Alzheimer disease (AD), activated microglia expressing MARCKS migrates around senile plaques. We reported that amyloid beta protein (A beta), a major component of senile plaques, activated MARCKS through a tyrosine kinase and PKC-delta. We have now identified another A beta signaling pathway through a mitogen-activated protein kinase (MAPK) involved in the phosphorylation of MARCKS and analysed cross-talk between PKC and MAPK pathways in primary cultured rat microglia. A selective inhibitor for MAPK kinase, PD098059, significantly inhibited the phosphorylation of MARCKS induced by A beta. Extracellulary regulated kinases, the activities of which were induced by A beta, directly phosphorylated a recombinant MARCKS in vitro. The MAPK pathway was sensitive to wortmannin, but not to a PKC inhibitor or to tyrosine kinase inhibitors. The activation of PKC by A beta was not sensitive to wortmannin. Our findings suggest involvement of the MAPK pathway through phosphoinositol 3-kinase in the phosphorylation of MARCKS in rat cultured microglia, an event may be associated with mechanisms activating microglia in AD.

Injuries to the posterolateral aspect of the knee accompanied by compression fracture of the anterior part of the medial tibial plateau

We present 12 cases of patients with injury to the posterolateral aspect of the knee accompanied by a compression fracture of the anterior part of the medial tibial plateau. There were 11 male patients and 1 female patient with an average age of 26 years (range, 17 to 44 years). There were 4 cases of posterolateral rotatory instability and 8 cases of straight lateral instability of the knee. The size of the compression fracture was classified into 2 types, small (8 cases) and large (4 cases). Although the mechanism of injury was considered to be hyperextension and varus force, the pattern of cruciate ligament injuries varied from case to case. The following 3 questions should be considered to determine which cruciate ligament is damaged: (1) Was the ipsilateral foot fixed to the ground? (2) Was forward inertia involved? (3) Was there a direct blow to the anteromedial aspect of the tibia or to the femur? Accompanied fractures of the medial tibial plateau were considered to have been compressed by the medial femoral condyle. The size of the accompanying compression fracture varied; 7 of 8 cases with a small-type fracture had posterior cruciate ligament injuries and 3 of 4 cases with a large-type fracture had anterior cruciate ligament injuries. The size of the fracture is determined by which point of the medial tibial plateau touched the medial femoral condyle. We propose that a compression fracture of the anterior part of the medial tibial plateau indicates a coexistent posterolateral aspect injury, and that especially a small compression fracture strongly suggests an accompanying posterior cruciate ligament injury, as well.

Patent foramen ovale as a possible risk factor for cryptogenic brain abscess: report of two cases

OBJECTIVE AND IMPORTANCE

Patent foramen ovale (PFO) has been suggested as a potential source of paradoxical embolism. A higher prevalence of PFO in ischemic stroke of unexplained cause has been recognized. Brain abscesses are commonly associated with a contiguous focus of infection, hematogenous spread from a distant focus, or cranial trauma. However, no predisposing factors, including a distant focus with unknown cause, are identified in approximately 15 to 30% of reported cases.

CLINICAL PRESENTATION

We encountered two patients with brain abscess presumably caused by dental infections. Both patients displayed PFO, through which right-to-left atrial contrast shunting was revealed by transesophageal echocardiography. Although the radiological location of the abscesses suggested hematogenous spread as a cause, the patients had no arteriovenous shunting other than the PFO, despite exhaustive investigations for a potential infectious route. The patients displayed no definite focal orofacial inflammatory signs during the postoperative course despite diagnosis of pyorrhea alveolaris or periodontitis.

INTERVENTION

In Patient 1, the abscess was aspirated stereotactically, and in Patient 2, the abscess disappeared radiologically after high-dose antibiotic treatment.

CONCLUSION

The mechanism of brain abscess formation putatively related to PFO should be different from that related to common dental sepsis. Analysis of these cases suggested that infectious embolism from a latent or even identifiable focus through the PFO may be an underrecognized cause of brain abscess, in contrast to simple seeding of the brain via transit of the infecting bacteria through the valveless emissary veins.

Time courses of increased expression of signaling transduction molecules induced by basic fibroblast growth factor in PC12 cells

We previously demonstrated that basic fibroblast growth factor (bFGF) protected neuronal injury in in vivo experimental cerebral ischemia. The precise molecular mechanisms of the neuroprotective effect of bFGF, however, remains unsolved. We investigated time courses of up-regulated molecules involved in intracellular signaling transduction pathways induced by bFGF in PC12 cells to explore the possible neuroprotective mechanism of bFGF action. In Western blot analysis, bFGF increased expression of Ras mainly in the early stage up to 24h, returning to the baseline level at 48 h. Expression of phosphatidylinositol 3-kinase (PI 3-kinase) was enhanced throughout the early and later stages, and was more up-regulated at 48 h compared to 24 h. The present findings suggest that bFGF might promote cell survival or proliferation mainly via Ras, and PI 3-kinase might be involved in cell survival and differentiation in PC12 cells.

Radial displacement of the medial meniscus in varus osteoarthritis of the knee

The macroscopic and histologic findings for 31 medial menisci and medial tibial plateaus obtained during total knee arthroplasty were examined to clarify the etiology and progression of varus osteoarthritis. Medial menisci were preserved fairly well in cases of severe osteoarthritis in which the medial joint space had already disappeared. The anterior segment was preserved in 26 (84%) menisci and the posterior segment was preserved in 11 (35%). The medial meniscus may have been preserved because of its radial displacement. Exposure of subchondral bone of the medial tibial plateau occurred in all 31 knees. The exposure of subchondral bone was centered in the anterior, middle, and posterior in nine, 10, and 12 medial tibial plateaus, respectively. There was a mechanical inconsistency between the pattern of preservation of the medial menisci and the location of exposure of subchondral bone on the medial tibial plateaus. The inconsistency reflects that the segment of the medial meniscus on which the excessive load was considered to exist was preserved fairly well. The authors' hypothesis for explaining this inconsistency is that radial displacement of the medial meniscus precedes narrowing of the medial joint space during progression of varus osteoarthritis, so that the displaced meniscus is saved from severe degeneration or attrition.

Amyloid beta protein activates PKC-delta and induces translocation of myristoylated alanine-rich C kinase substrate (MARCKS) in microglia

The increased accumulation of activated microglia containing amyloid beta protein (Abeta) around senile plaques is a common pathological feature in subjects with Alzheimer's disease (AD). Much less is known, however, of intracellular signal transduction pathways for microglial activation in response to Abeta. We investigated intracellular signaling in response to Abeta stimulation in primary cultured rat microglia. We found that the kinase activity of PKC-delta but not that of PKC-alpha or -epsilon is increased by stimulation of microglia with Abeta, with a striking tyrosine phosphorylation of PKC-delta. In microglia stimulated with Abeta, tyrosine phosphorylation of PKC-delta was evident at the membrane fraction without an overt translocation of PKC-delta. PKC-delta co-immunoprecipitated with MARCKS from microglia stimulated with Abeta. Abeta induced translocation of MARCKS from the membrane fraction to the cytosolic fraction. Immunocytochemical analysis revealed that phosphorylated MARCKS accumulated in the cytoplasm, particularly at the perinuclear region in microglia treated with Abeta. Taken together with our previous observations that Abeta-induced phosphorylation of MARCKS and chemotaxis of microglia are inhibited by either tyrosine kinase or PKC inhibitors, our results provide evidence that Abeta induces phosphorylation and translocation of MARCKS through the tyrosine kinase-PKC-delta signaling pathway in microglia.

Surgical treatment of falcotentorial meningioma

Meningiomas arising from the falcotentorial junction are rare. Among our surgical experience of 375 meningiomas, only 4 cases of so-called falcotentorial meningiomas were encountered. We present these four surgical cases. An occipital transtentorial approach was used in three cases, and a combined midline occipital and suboccipital approach in one case. Total tumour excision was impossible in two cases because of engulfing deep venous structures including the great vein of Galen. Postoperative Gamma knife radiosurgery was performed in these two cases. On the other hand, a posteriorly located tumour was relatively easy to remove, and macroscopic total removal was accomplished. In conclusion, precise microvascular anatomical knowledge is indispensable to satisfactorily excise meningiomas in the falcotentorial area without significant morbidity.

[Anesthetic management of a patient with Crow-Fukase syndrome complicated with severe heart failure]

A 31-year-old man with Crow-Fukase syndrome was scheduled for orthopedic surgery of the right lower limb. Preoperative examination revealed severe heart failure due to cardiomyopathy. Anesthesia was maintained with sevoflurane and nitrous oxide in oxygen, and supplemental fentanyl combined with continuous epidural block. During surgery, we evaluated cardiac function using transesophageal echocardiography. To maintain his cardiac function, intravenous dopamine and dobtamine were administered continuously, and the surgery was performed successfully. We must take care of cardiac function during anesthetic management of a patient with this syndrome.

Acute respiratory and metabolic acidosis induced by excessive muscle contraction during spinal evoked stimulation

Spinal somatosensory evoked potentials (SSEPs) have been used to monitor spinal cord function during corrective scoliosis surgery. We report three cases in which direct epidural stimulation for measurement of SSEPs produced paraspinal muscle contraction, resulting in respiratory and metabolic acidosis. In two of the cases, SSEP-induced acidosis was observed even when only the first twitch of the train-of-four response was detectable after a second dose of muscle relaxant. In one of these two cases, the acidosis was abolished after a sufficient dose of vecuronium to ablate the twitch response. To prevent SSEP-induced respiratory and metabolic acidosis, we recommend that SSEPs should be measured only when profound neuromuscular blockade has been obtained.

Phosphorylation of tau is regulated by PKN

For the phosphorylation state of microtubule-associated protein, tau plays a pivotal role in regulating microtubule networks in neurons. Tau promotes the assembly and stabilization of microtubules. The potential for tau to bind to microtubules is down-regulated after local phosphorylation. When we investigated the effects of PKN activation on tau phosphorylation, we found that PKN triggers disruption of the microtubule array both in vitro and in vivo and predominantly phosphorylates tau in microtubule binding domains (MBDs). PKN has a catalytic domain highly homologous to protein kinase C (PKC), a kinase that phosphorylates Ser-313 (= Ser-324, the number used in this study) in MBDs. Thus, we identified the phosphorylation sites of PKN and PKC subtypes (PKC-alpha, -betaI, -betaII, -gamma, -delta, -epsilon, -zeta, and -lambda) in MBDs. PKN phosphorylates Ser-258, Ser-320, and Ser-352, although all PKC subtypes phosphorylate Ser-258, Ser-293, Ser-324, and Ser-352. There is a PKN-specific phosphorylation site, Ser-320, in MBDs. HIA3, a novel phosphorylation-dependent antibody recognizing phosphorylated tau at Ser-320, showed immunoreactivity in Chinese hamster ovary cells expressing tau and the active form of PKN, but not in Chinese hamster ovary cells expressing tau and the inactive form of PKN. The immunoreactivity for phosphorylated tau at Ser-320 increased in the presence of a phosphatase inhibitor, FK506 treatment, which means that calcineurin (protein phosphatase 2B) may be involved in dephosphorylating tau at Ser-320 site. We also noted that PKN reduces the phosphorylation recognized by the phosphorylation-dependent antibodies AT8, AT180, and AT270 in vivo. Thus PKN serves as a regulator of microtubules by specific phosphorylation of tau, which leads to disruption of tubulin assembly.