Keisuke Onoda

PREOPERATIVE SIMULATION FOR MICROVASCULAR DECOMPRESSION IN PATIENTS WITH IDIOPATHIC TRIGEMINAL NEURALGIA: VISUALIZATION WITH THREE-DIMENSIONAL MAGNETIC RESONANCE CISTERNOGRAM AND ANGIOGRAM FUSION IMAGING

OBJECTIVEPrecise assessment of the complex nerve-vessel relationship at the root entry zone of the trigeminal nerve is useful for planning microvascular decompression in patients with idiopathic trigeminal neuralgia. We have applied a fusion imaging technique of three-dimensional (3-D) magnetic resonance cisternography and co-registered 3-D magnetic resonance angiography (MRA) that allows virtual reality for the preoperative simulation of the neurovascular conflict at the trigeminal nerve root entry zone. METHODSFusion images of 3-D magnetic resonance cisternograms and angiograms were reconstructed by a perspective volume-rendering algorithm from the volumetric data sets of magnetic resonance cisternography, obtained by a T2-weighted 3-D fast spin echo sequence, and co-registered MRA, by a 3-D time-of-flight sequence. Consecutive series of 12 patients with idiopathic trigeminal neuralgia were studied with fusion 3-D magnetic resonance cisternogram and MRA in the preoperative assessment for the microvascular decompression of the affected trigeminal nerve. RESULTSThe complex anatomical relationship of the offending vessels to the trigeminal nerve root entry zone was depicted on the fusion 3-D magnetic resonance cisternogram and MRA. The presence of offending vessels and compressive site of neurovascular conflict was assessed from the various viewpoints within the cistern and was presumed by the preoperative simulation through the surgical access (surgeons-eye view). The blinded surgical trajectory was discerned by the virtual image through the opposite direction projected from above (birds-eye view). The 3-D visualization of the nerve-vessel relationship with fusion images was consistent with the intraoperative trajectory and findings. CONCLUSIONFusion imaging of 3-D magnetic resonance cisternogram and MRA may prove a useful adjunct for the diagnosis and decision-making process to execute the microvascular decompression in patients with idiopathic trigeminal neuralgia.

Antivasospastic and antiinflammatory effects of caspase inhibitor in experimental subarachnoid hemorrhage

OBJECT Inflammation in the subarachnoid space and apoptosis of arterial endothelial cells have been implicated in the development of delayed cerebral vasospasm after subarachnoid hemorrhage (SAH). The authors investigated mechanisms of possible antivasospastic effects of N-benzyl-oxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK), a caspase inhibitor that can inhibit both inflammatory and apoptotic systems, in animal models of SAH. METHODS Rabbits were assigned to three groups of eight animals each and were subjected to SAH by injection of blood into the cisterna magna. The experiments were performed in the following groups: SA only, SAH + vehicle, and SAH + Z-VAD-FMK. The Z-VAD-FMK (1 mg) or vehicle (5% dimethyl sulfoxide) was intrathecally administered before SAH induction. Diameters of the basilar artery (BA) were measured on angiograms obtained before and 2 days after SAH. The BA diameter on Day 2 was expressed as a percentage of that before SAH. Interleukin (IL)-1 in the cerebrospinal fluid (CSF) was examined using Western blotting, and brains were immunohistochemically examined for caspase-1 and IL-1beta. In a separate experiment, 20 rats were subjected to SAH and their brains were immunohistochemically assessed for caspase-1, IL-1beta, and macrophages. RESULTS. In rabbits, Z-VAD-FMK significantly attenuated cerebral vasospasm (the BA diameter on Day 2 in SAH-only, SAH + vehicle, and SAH + Z-VAD-FMK groups was 66.6 +/- 3.2%, 66.3 +/- 3.7%, and 82.6 +/- 4.9% of baseline, respectively), and suppressed IL-1beta release into the CSF and also suppressed immunoreactivities of caspase-1 and IL-1P in macrophages infiltrating into the subarachnoid space. Immunoreactivities for caspase-1 and IL-1P were observed in immunohistochemically proven infiltrating macrophages in rats. CONCLUSIONS These results indicate that caspase activation may be involved in the development of SAH-induced vasospasm through inflammatory reaction.

Role of Extracellular Matrix in Experimental Vasospasm Inhibitory Effect of Antisense Oligonucleotide on Collagen Induction

BACKGROUND AND PURPOSE Although it has been suggested that collagen plays a role in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage, there has been no constructive research to prove it directly. In this study we stopped the transcription of the procollagen type I gene by introducing antisense oligonucleotides for its mRNA in a rat femoral artery model of vasospasm induced by blood and assayed the changes in the vasoconstrictive activity of the vessel and expression of the procollagen mRNA. METHODS We applied antisense, sense, or missense oligonucleotides, located at the carboxyl propeptide region for alpha 1(I) procollagen mRNA, onto the femoral artery in a rat femoral artery model of vasospasm. The diameter of the artery was measured by angiography. The transcription level of the procollagen gene in the arterial tissue was assayed by use of reverse transcription-polymerase chain reaction. Morphological change in the artery was observed with aldehyde-fuchsin-Masson-Goldner staining. RESULTS In the model, when the artery was exposed to antisense oligonucleotides in pluronic gel for 5 days to prevent arterial contraction, the contraction was inhibited at a significant level (76.0% +/- 5.6) when compared with that in control experiments using sense oligonucleotides (64.0% +/- 2.4), missense oligonucleotides (63.5% +/- 3.5), or gel alone (62.1% +/- 5.8). The application of antisense oligonucleotide resulted in a marked decrease in alpha 1(I) procollagen mRNA expression as determined by polymerase chain reaction, indicating that the collagen reduction by antisense oligonucleotides occurred at the transcription level. Histological staining suggested that collagen accumulation at the site in the artery where antisense oligonucleotide had been administered was indeed less than that in the control artery. CONCLUSIONS The results indicate that the induction of procollagen type 1 could cause pathogenesis of the arterial contraction induced by blood in a rat femoral vasospasm model.

Severity Analysis of Neurovascular Contact in Patients with Trigeminal Neuralgia: Assessment with the Inner View of the 3D MR Cisternogram and Angiogram Fusion Imaging

BACKGROUND AND PURPOSE: Neurovascular contact (NVC) of the trigeminal nerve is not only detected at the affected trigeminal nerve in patients with trigeminal neuralgia (TN) but is also observed at the asymptomatic nerves on the side contralateral to the TN as well as in normal nerves in control subjects. The frequency and severity of the NVC among the affected, contralateral, and normal trigeminal nerves were analyzed by 3D MR cisternogram and angiogram fusion imaging in relation to the cause of TN. MATERIALS AND METHODS: The inner view of the fusion MR imaging projected from inside the trigeminal nerve was used. The severity of the NVC was classified as none, simple, moderate, or severe, according to the nerve circumference in contact with the vessel. The NVC was analyzed in the affected nerves (n = 66) and the contralateral nerves (n = 66). Forty patients underwent microvascular decompression surgery, and 26 were treated medically. The NVC at the normal trigeminal nerves (n = 78) was studied in 39 control subjects without symptoms of TN. RESULTS: The NVC in the affected trigeminal nerve was observed more frequently and much more severely than that at the contralateral and normal trigeminal nerves in controls (P < .01). Additionally, the NVC in the surgical patients was more severe than that in the medically treated patients (P < .01). CONCLUSIONS: Severity analysis of the NVC with the inner view of the fusion MR imaging may provide useful information in the diagnosis of TN and can be a helpful adjunct in treatment planning for patients with TN.

Time course of the diameter of the major cerebral arteries after subarachnoid hemorrhage using corrosion cast technique

Abstract In this report, we examined whether corrosion cast method is also applicable for the measurement and estimation of the rat major arteries in which subarachnoid hemorrhage (SAH) is produced. Additionally, we have examined the diameters of the rat major arteries following SAH. A total of 0.3 ml autologous blood was injected into the cisterna magna of male Sprague-Dawley rats for the SAH model. A perfusion of a semi-polymerized casting medium was performed, 10 min, 30 min, 1 h, 4 h, 8 h, 1 day, 2 days, 3 days, 5 days, and 7 days after SAH. The brains were corroded in a 10% NaOH solution. The BA and the other major arteries were then measured using scanning electron microscopy (SEM). Macroscopic observation and hematoxylin-eosin (HE) staining were also performed. Using the corrosion cast method, the biphasic contractile response was observed in the BA; 8.3% and 11.6% contractions were observed 30 min and 1 day after SAH, respectively. In addition, there was almost no smooth muscle or adventitial thickening in the chronic stage. In contrast, the dilative response was observed in the internal carotid artery and middle cerebral artery 10 min after SAH. Macroscopic findings and HE staining revealed that the extensive basal subarachnoid hematoma had almost disappeared by day 2. These results indicate that in this model, the minimal spasm, which occurs one day after SAH, can be explained by the small capacity of the rat subarachnoid space and the rapid cerebrospinal fluid washout around major vessels at the cerebral base. Moreover, the present data also show the compensatory dilatation in the ICA and MCA in the early stage after SAH.

Endovascular treatment for elderly patients with ruptured aneurysm.

We report our results of endovascular treatment for elderly patients with ruptured aneurysm and discuss the indication for treatment. One hundred and thirty four consecutive patients with ruptured aneurysm treated in our institute during the last 4 years were retrospectively evaluated. Fifty eight patients were included in group A (over 70 years old), and 76 patients in group B (under 69 years old). In both groups, the outcome was strongly related to the preoperative Hunt & Kosnik grade. However, significant risk factors (i.e. pneumonia, rupture of extracranial aneurysm) which make prognosis poor were more common in group A. Group A showed poor outcome in grade III patients, although there were no outcome differences between the two groups in patients of other grades. Endovascular treatment for elderly patients with ruptured aneurysms seemed to be useful. Their outcome was strongly related to their preoperative condition. General risk factors should be evaluated before treatment, especially in elderly patients. Patients with low Hunt & Kosnik grade seem to be most suitable for endovascular treatment. On the other hand, outcome of patients with poor preoperative grade was worse despite the less invasive nature of endovascular treatment. An improvement of outcome in grade III patients is desirable.

Fatal glioblastoma after Gamma Knife radiosurgery for arteriovenous malformation in a child

We describe a fatal case of glioblastoma multiforme that was induced by Gamma Knife radiosurgery (GKS; Elekta AB, Stockholm, Sweden) for an arteriovenous malformation (AVM). A 4-year-old girl presented with repeated convulsions. Imaging studies revealed an AVM located in the right thalamus. One year after initial symptoms, GKS was performed to obliterate the nidus. The maximum and marginal radiation doses were 32 and 16Gy, respectively. Seventy months after GKS, the patient represented with severe headache. MRI showed a poorly demarcated tumor with heterogeneous gadolinium enhancement in the right thalamus and adjacent to the white matter of the temporal lobe. After a generalised convulsion, the patient deteriorated into a deep coma. CT scans showed severe brain swelling with intratumoral hemorrhage. An emergency craniotomy was performed, and the hematoma was removed. During this surgery, a tumor mass, which was found adjacent to the hematoma, was resected. Microscopic examination revealed glioblastoma multiforme. Despite intensive treatment, the patient died 1month after surgery. A GKS-induced secondary tumor is a rare but serious complication. It is important to be aware of the adverse effects of GKS, including secondary neoplasms, before its clinical application, especially in young patients.

Novel Protein Transduction Method by Using 11R. An Effective New Drug Delivery System for the Treatment of Cerebrovascular Diseases

Background and Purpose— A motif of 11 consecutive arginines (11R) is reported to be one of the most effective protein transduction domains for introducing proteins into the cell membrane. We therefore examined the transduction efficiency of 11R in cerebral arteries. Methods— Basilar arteries (BAs) obtained from rats were incubated with either 11R-enhanced green fluorescent protein (11R-EGFP) or EGFP without 11R. After incubation, expression of 11R-EGFP or EGFP in BA serial sections was observed by fluorescence microscope. In an additional in vivo experiment, 11R-EGFP or EGFP was injected into the cisterna magna with or without subarachnoid hemorrhage. The 11R-EGFP or EGFP was injected just after the autologous blood injection, and then the expression of 11R-EGFP or EGFP in BA sections was also observed by fluorescence microscope. Results— The 11R-EGFP signal was much stronger than that of EGFP in all layers of the rat BA, in both in vivo and ex vivo experiments. Moreover, the 11R-EGFP was transduced into the BA immediately (2 hours after the injection). Interestingly, 11R-fused fluorescent protein was transduced especially into the tunica media of the BA. Conclusions— The 11R-fused fluorescent protein effectively penetrates into all layers of the rat BA, especially into the tunica media. This is the first study to our knowledge to demonstrate the successful transduction of a protein transduction domain fused protein into the cerebral arteries.

Triple-catheter technique in the transvenous coil embolization of an isolated sinus dural arteriovenous fistula

OBJECTIVE Dural arteriovenous fistulae involving the transverse-sigmoid sinus, which is occluded at its proximal and distal ends (i.e., an isolated sinus), carry a high risk of intracranial hemorrhage or progressive neurological deficits. Although transvenous coil embolization is a useful and safe treatment for such lesions, it is often difficult to reach into the isolated sinus through the occluded sinus using the percutaneous catheter approach. METHODS We report the successful treatment of two patients with transverse-sigmoid dural arteriovenous fistulae with isolated sinus using the percutaneous transvenous triple-catheter technique. A 6-French guiding catheter was placed at the internal jugular vein followed by a second 4-French catheter positioned at the end of the occluded sinus. A third microcatheter was then navigated into the isolated sinus with support of the second catheter. RESULTS Although initial attempts to reach into the isolated sinus without the second catheter failed, insertion of the second catheter resulted in successful navigation of the third microcatheter into the affected sinus in both cases. Complete cure was obtained in both cases by coil packing of the affected sinus. CONCLUSION Although careful maneuvering is required, this triple-catheter technique is useful for treatment of dural arteriovenous fistulae with isolated sinus.

Continuous evaluation of regional oxygen saturation in cerebral vasospasm after subarachnoid haemorrhage using INVOS®, portable near infrared spectrography

Background Although several tools are available for the detection of cerebral vasospasm after subarachnoid haemorrhage, it has remained difficult to identify vasospasm timely and accurately. INVOS® monitoring measures the oxygen saturation by using near infrared spectroscopy, and in this study we examined the usefulness of this system for the detection of vasospasm.