Yoshiteru Shose

Effect of clot removal and surgical manipulation on regional cerebral blood flow and delayed vasospasm in early aneurysm surgery for subarachnoid hemorrhage

BACKGROUND Effect of clot removal and surgical manipulation on cerebral blood flow (CBF) and delayed vasospasm was studied in early aneurysm surgery for subarachnoid hemorrhage (SAH). METHODS Thirty-two patients in this study fulfilled the following criteria: ruptured anterior communicating aneurysms, computed tomography (CT) within 2 days and unilateral pterional approach within 3 days after the ictus, bilaterally symmetrical clots without intracerebral hematoma, no postoperative complication, and CBF studies with single photon emission computed tomography (SPECT) with 123I-IMP. RESULTS Postoperative regional hypoperfusion due to brain retraction was frequently recognized on 123I-IMP-SPECT without infarction. The regional CBF (rCBF) showed a continuous fall during the first 4 weeks after the ictus, followed by improvement. The rCBF in the vicinity of the surgical route was significantly lower, especially in the acute stage (Day 3-7). A significant association between decrease of cisternal blood after surgery and the degree of local vasospasm and local CBF values during spasm stage was observed in the interhemispheric cisterns, A2 and medial frontal cortex, but not in the sylvian fissure or insular cisterns, M1 or M2, and frontal watershed and temporal cortex. CONCLUSIONS The present study provides evidence for the effectiveness of direct clot removal by early surgery for SAH on local vasospasm and CBF reduction. However, a potential improvement in local CBF with clot removal could be masked by brain retraction, which was demonstrated to affect rCBF adversely. Therefore, it is critical to perform brain retraction as gently as possible.

Saccular Aneurysms of the Proximal (M1) Segment of the Middle Cerebral Artery

We report A series of 20 consecutive patients with 21 saccular aneurysms of the proximal (M1) segment of the middle cerebral artery. The incidence of M1 aneurysms was 3.0% among 660 patients with intracranial aneurysms and 12.9% among 155 patients with middle cerebral artery aneurysms in our center. Of the 20 patients, 2 were men and 18 were women. The aneurysms were classified into two types: the superior wall type (9 cases), arising at the origin of the lenticulostriate or fronto-orbital artery, and the inferior wall type (12 cases), arising at the origin of the early temporal branches. Twelve (60%) patients had ruptured M1 aneurysms. The incidence of multiple aneurysms was high (nine patients, 45%), and M1 aneurysms were responsible for subarachnoid hemorrhage in four patients. Of 14 M1 aneurysms greater than 5 mm in diameter, 11 (78.6%) ruptured. In contrast, only one (14.3%) of seven small (< or = 5 mm) aneurysms ruptured. In 12 patients with ruptured M1 aneurysms, intracerebral hematomas were recognized in 6 (50%). Intracerebral hematomas by the superior wall M1 aneurysms were located in the frontal lobe, and those by the inferior wall M1 aneurysms were in the temporal lobe. Fifteen patients (75%) made a useful recovery 6 months after surgery. Four patients (20%), who were in poor grade condition preoperatively, remained severely disabled. One patient died of sepsis 2 months after she recovered well from the operation. Special attention to the lenticulostriate arteries to avoid injury is critical for successful surgical treatment.

Influence of degree of carotid artery stenosis and collateral pathways and effect of carotid endarterectomy on cerebral vasoreactivity.

OBJECTIVE The goal was to determine the influence of the degree of internal carotid artery (ICA) stenosis and collateral pathways on cerebral vasoreactivity (CVR). The effect of carotid endarterectomy on CVR is also presented. METHODS For 36 patients with unilateral ICA stenosis of at least 70%, regional cerebral blood flow (rCBF) and regional CVR (rCVR) were investigated before and after carotid endarterectomy, with resting and acetazolamide-challenge single photon emission computed tomographic scans. The degree of ICA stenosis and the status of the collateral pathways (sizes of the A1 segment and the posterior communicating artery) were evaluated by angiography. RESULTS Thirteen patients were classified as Type N/N (normal rCBF and normal rCVR), 5 as Type R/N (reduced rCBF and normal rCVR), 6 as Type N/R (normal rCBF and reduced rCVR), and 12 as Type R/R (reduced rCBF and reduced rCVR). The degree of ICA stenosis correlated with rCVR status. The size of the A1 segment was a second-rank factor and was less effective in affecting rCVR. The size of the posterior communicating artery was not associated with rCVR. The predictive value of reduced rCVR for postoperative improvement (100%) was significantly higher than that of reduced rCBF (50%). CONCLUSION The present results indicate that the degree of ICA stenosis is a more significant determinant of CVR than are the collateral pathways in patients with carotid artery stenosis. The high predictive rate of reduced rCVR for postoperative improvement implies that acetazolamide-challenge single photon emission computed tomographic scanning might be useful in selecting patients with asymptomatic ICA stenosis who might benefit from carotid endarterectomy.

Intragastric Migration of a Ventriculoperitoneal Shunt Catheter

A child developed bacterial meningitis and shunt dysfunction 2 years after the insertion of a ventriculoperitoneal shunt for posttraumatic hydrocephalus. The distal end of the shunt catheter had penetrated the gastric wall. We found no other report of intragastric shunt catheter migration with successful treatment.

Blade-deviated fenestrated clips for anterior communicating artery aneurysms

Blade-deviated fenestrated clips developed by one of the authors were applied very successfully in 15 cases of A Com A aneurysms which corresponded to 32% of the aneurysms upon which were operated. Of the 15, 13 cases were projected superiorly, which is the most difficult and hazardous type if ruptured at the neck. The characteristic feature of the clip is the lateral deviation of occluding blades. The superiorly projecting type A Com A aneurysm is located posterolateral to the A Com A in the operative field, and the clips were extremely useful in the aneurysms in providing safer and more exact occlusion via parallel closure of the A Com A or the aneurysm neck.

Post-Shunt Isolated Compartments in Hydrocephalus: Proposal for a New Classification and Experimental Proof of the Pathophysiology

The clinical features and pathophysiology of specific forms of postshunt isolated compartments were analyzed. The possible pathogenesis of the individual clinical entity was discussed on the basis of various experimental studies, which included morphological evaluation and pressure monitoring in a canine slit-ventricle model a silicon ventricular system simulation model for post-shunt ICP dynamics analysis, and so forth. A clinically applicable classification was used to evaluate the progression of hydrocephalus (Stage I–IV), and to define the compartment isolation after shunting in previously communicating cerebral ventricles and the central canal of the spinal cord (Type I–IV).

CSF Dynamics in Children: A quantitative analysis of the relativity of major and minor pathways of cerebro-spinal fluid dynamics

Cerebrospinal fluid (CSF) dynamics in infants and children is still obscure. This paper aims to analyze the characteristics of CSF dynamics in the younger age group and to clarify the changes both in the acute/chronic hydrocephalic status and in the post-shunt condition on the basis of our experience with 118 cases of metrizamide CT cisternography. In order to pursue the CSF passive movements, the exact regional CT numbers were obtained by means of the ROI method in each case at 3, 6, and 24 hours after metrizamide injection. The results revealed that, in the normal CSF dynamics in both the major and minor pathways in children, it took more than 24 hours until the regional metrizamide was completely cleared up.