Tohru Hoshida

Surgery for dural arteriovenous fistula in superior sagittal sinus and transverse sigmoid sinus

The aim of this study was to evaluate the outcome of surgically treated dural arteriovenous fistula (DAVF). The authors performed surgical removal of DAVF in 12 patients. The locations of DAVF were the transverse sigmoid sinus in seven patients and superior sagittal sinus in five patients. These 12 patients had undergone endovascular embolisation prior to removal. Among them, six patients were completely cured, according to angiography immediately after embolisation, but these six patients showed the recurrence of DAVF within 1 year. The other six patients showed a decrease of feeding vessels. Therefore, all 12 patients underwent surgical removal of DAVF. The surgical strategies were as follows. The feeding vessels and the cortical veins with retrograde filling were occluded and cut. The affected sinus was skeletonised, and if it was occluded or almost occluded, the sinus was removed. Postoperatively, transient aphasia was seen in one patient. There was no surgical morbidity or mortality. During the follow-up period (mean 2.9 years), no recurrence of DAVF was seen. Surgical treatment is a safe and effective treatment manoeuvre for DAVF around the transverse sigmoid sinus and superior sagittal sinus.

Extensive cervical laminoplasty for patients with long segment OPLL in the cervical spine : An alternative to the anterior approach

We investigated treatment of long segment cervical OPLL by posterior decompression using a laminoplasty technique. Our aim was to both decompress the spinal cord and also to preserve neck motion. There were 38 patients treated by this posterior approach. Twenty-eight patients underwent C1-C7 expanding laminoplasty, 4 patients underwent C1-T1 expanding laminoplasty, and 6 patients C2-C7 expanding laminoplasty. The transverse width of the open-door laminoplasty was sufficient to achieve decompression of not only the spinal cord but also the nerve root outlets at each laminoplasty level. There were no complications related to this surgical technique, nor late deterioration in the mean follow up period of 4. 5 years. We propose expanding laminoplasty as an important option for the treatment of long segment cervical OPLL.

Accuracy and Availability of the Computed Assisted Neurosurgery Navigation System during Epilepsy Surgery

The magnetic-force-based Computed Assisted Neurosurgery System was used for epilepsy surgery to localize targets accurately in the operative field. The correlation between X components of target coordinates in the axial plane and the coronal plane for the same target was strong in all cases. Concerning Y components, there were statistically significant differences in 2 cases. There was a case that showed statistically significant differences only in the Z dimension. The interdisk distance by data sets of coordinates obtained from neuronavigation was calculated to quantify localization error, and the measuring error ranged from –5 to 13.3 mm (1.3 ± 3.2 mm). The magnitude of the application errors in this study tended to be large in the frontal and vertex regions.

Usefulness of the Dipole Tracing Method with a Scalp-Skull-Brain Head Model: Relationship between the Epileptic Focus and Equivalent Current Dipole Locations

Purpose: We examined whether the dipole tracing (DT) method with a realistic three-shell head model and inhomogeneous electric conductivity is useful to estimate the epileptic focus from interictal spikes. Method: This study included 17 temporal lobe epilepsy (TLE) cases, classified into three types as type A (unilateral), type B (intermediate) and type C (bilateral) and 5 extratemporal epilepsy (XTLE) cases. The epileptic areas were determined by noninvasive and/or invasive examinations. Selected interictal spikes were analyzed and the calculated equivalent current dipoles (ECDs) of dipolarity greater than 0.98 were superimposed over the realistic head model in each patient. We evaluated the ECD concentration within and around the epileptic area. Results: In TLE cases, types A showed better ECD concentration (87%) within the epileptic area than other types (type B: 68%; type C: 74%). XTLE exhibited variable ECD distribution within and around the epileptic area. Conclusion: The DT method with a realistic head model and inhomogeneous electric conductivity can be useful to estimate the epileptic area from interictal spikes, especially in unilateral TLE cases.

Functional brain mapping detected by cortical stimulation using chronically implanted electrodes

Abstract Purpose: The goal of epilepsy surgery is to determine as accurately as possible the epileptogenic zone and eloquent areas preoperatively. We studied functional brain mapping using chronically intracranial electrode stimulation in 37 cases of partial epilepsy. Methods: The mean age was 28 (2–67) years. The average number of implanted electrodes was 88. Alternating electric currents with 1–10-s duration were used. Results: The mean distance from the cross-point of the Sylvian fissure and central sulcus to the temporal tip was 58 (41–79) mm. The most inferior end of the hand area was 37 (17–54) mm superior to the cross-point. Negative motor areas (NMAs) were demonstrated between the anterior language areas (ALAs) and tongue motor areas in 40% of the 17 cases. Half of the anterior language areas (Brocas area) were not demonstrated just above the Sylvian fissure. The anterior end of the posterior language areas (PLAs) (Wernickes area) was found to be, on the average, 48 mm posterior to the temporal tip. If we evaluate the language areas by spontaneous speech (SS) and picture naming (PN) tasks, we underestimate 20% of the language areas. Conclusions: Eloquent areas can be identified in individual patients using cortical stimulation. We can recognize and differentiate definite and non-definite language areas.

A case of early-onset benign occipital seizure susceptibility syndrome: decreased cerebral blood flow in the occipital region detected by interictal single photon emission computed tomography, corresponding to the epileptogenic focus

Early-onset benign childhood occipital seizure susceptibility syndrome (EBOSS) recently described by Panayiotopoulos, is an early-onset variant of benign childhood epilepsy with occipital paroxysms. EBOSS is characterized by partial seizures that are predominantly manifested at night and associated with deviation of the eyes, vomiting and impairment of consciousness, but without ictal visual symptoms or postictal headache. The clinical features of our case were consistent with those of EBOSS, and we therefore diagnosed the patient as having a typical form of EBOSS. Neuroimaging by CT, MRI and MR angiography did not reveal a focal lesion. Interictal single photon emission computed tomography (SPECT) revealed decreased cerebral blood flow in the right occipital region corresponding to the epileptogenic focus shown on EEG. It remains unclear whether our finding on SPECT reflects secondary hypoperfusion due to minor morphological abnormality or immediate functional hypoperfusion. No reference to SPECT in a case of EBOSS has appeared in the literature to date. This report provides a better understanding of benign childhood epileptic syndromes with occipital spikes.

Manual and digitizer measurements of amygdalohippocampal volume: Reliability in comparison to computer-based measurement

Volumetric magnetic resonance imaging (MRI) studies of amygdala and hippocampus (AH) are useful for lateralization in surgical candidates evaluated because of intractable temporal lobe epilepsy.-6 The MRI-based lateralization was highly concordant with the side of epileptogenic focus localized by EEG.1-476 Computer-assisted volumetry is well known, but it requires special equipment and trained personnel. 1-4,6 Manual measurement directly on MRI films5 and measurement using a digitizer with magnification were tested, and reliability and repeatability of these two methods were compared with those of computer-based volumetry.

Intractable epilepsy: Expression of substance P in cortical dysplastic neurons

Pediatr. 2006; 149: 336–41. 9 Yoshikawa H, Nomura Y, Masuda K et al. Four cases of Kawasaki syndrome complicated with myocarditis. Circ. J. 2006; 70: 202– 5. 10 Omland T, Aakvaag A, Bonarjee VV et al. Plasma brain natriuretic peptide as an indicator of left ventricular systolic function and long-term survival after acute myocardial infarction. Comparison with plasma atrial natriuretic peptide and N-terminal proatrial natriuretic peptide. Circulation 1996; 93: 1963–9.

Estimation of the Epileptic Focus in Temporal Lobe Epilepsy‐ Investigation with Dipole Tracing Using a Realistic Three‐Shell Head Model

Purpose: The location of the electrical generator in the brain can be estimated with dipole tracing. We estimated the equivalent current dipole with scalp electroencephalogram (EEG) in patients with temporal lobe epilepsy by using dipole tracing, and compared the results with the epileptogenic focus identified by long‐term subdural EEG recording.