Yasushi Shin

Spinal dural arteriovenous fistula with perimesencephalic subarachnoid haemorrhage

A case is reported of a 66 year old woman presenting with perimesencephalic subarachnoid haemorrhage (SAH) which was caused by a spinal dural arteriovenous fistula at the C1 level. The fistula drained into the venous system of the posterior cranial fossa through a perimedullary vein. The bleeding was thought to result from venous hypertension induced by the fistula. This case may support the hypothesis that perimesencephalic non-aneurysmal SAH can be ascribed to venous bleeding and that venous hypertension is the key to its pathology.

Clinical features of postoperative cerebral venous infarction

SummaryThere is a potential risk of sacrificing the cortical vein during neurosurgical operations, particularly in the interhemispheric or subtemporal approach. An impaired cortical vein might cause cerebral venous circulatory disturbances (CVCDs) resulting in venous infarction. In this article, we have reviewed the management and results of eight cases with symptomatic postoperative venous infarction.We have encountered eight cases with symptomatic postoperative venous infarction (0.3%) during the past 5 years. The series is composed of 3 males and 5 females, with ages that ranged from 43 to 76 years (mean age of 58.1 years), and consisted of five brain tumors, one cavernoma, one dural AVF, and one trigeminal neuralgia. Initial symptoms occurred intra-operatively in two, on 0 day after the operation in one, 1 day in three, 3 days in one, and 4 days in one case. The symptoms were intra-operative brain edema in two cases, disorientation in one, cerebellar signs in one, hemiparesis in one, aphasia in two, and headache in one case. Two cases required surgical intervention. The results were a good outcome in 6 and a fair outcome in 2 cases.In conclusion, there are two types of postoperative venous infarction; severe onset (severe type) and gradual onset (mild type). The former needs immediate treatment from the intra-operative period onward, and the prevention of the ongoing venous thrombosis is essential in the latter.

Expression of angiogenic growth factor in the rat DAVF model.

Abstract Objective: The precise mechanisms responsible for the development and growth of dural arteriovenous fistula (DAVF) remain unclear, but it has been hypothesized that vascular endothelial growth factor (VEGF) might be involved in the pathogenesis. The aim of this study was to examine the expression of VEGF in the rat DAVF model. Methods: Forty-five Sprague–Dawley rats were used in two experiments. In Experiment 1 (n = 20, including sham-operated controls), VEGF expression was analysed by Western blots in three different rat DAVF models: model I: common carotid artery–external jugular vein (CCA–EJV) anastomosis (n = 5); model II: sagittal sinus thrombosis and bipolar coagulation of the vein draining the transverse sinus (n = 5); model III: CCA–EJV anastomosis and bipolar coagulation of the vein draining the transverse sinus and sagittal sinus thrombosis to induce venous hypertension (n = 5). Based on the results of Experiment 1, Western blots were performed at weekly intervals 1, 2 and 3 weeks in Experiment 2 following induction of venous hypertension in model III (n = 5 at each time point and n = 5 sham controls); in addition, VEGF expression was immunohistochemically examined in the dura and the brain near the occluded sinus in five model III animals after 1 week. Results: In Experiment 1, Western blot analysis showed barely detectable bands with molecular weights of 45 kD, corresponding to VEGF, in the sham group, but the highest level of VEGF was induced in model III, followed by models I and II (model III>model I>model II). In Experiment 2, the expression of VEGF peaked 1 week after induction of venous hypertension in model III, decreasing in a linear fashion over 2 and 3 weeks (week 1>weeks 2 and 3). The expression of immunoreactive VEGF was restricted in the connective tissue and the endothelial layer of the dura matter, cerebral cortical tissue and neurons of the basal ganglia. Conclusion: Our results strongly suggest a possible contribution of an angiogenic factor to the growth of DAVF. Venous ischemia by venous hypertension might be a mechanism for inducing up-regulation of angiogenic factor expression.

The use of ultrasonic bone curettes in spinal surgery

SummaryObject. The author describes a clinical applications, procedure, and efficacy of ultrasonic bone curette (UBC) (bone-removal bar) in spinal surgery.Methods. From July 2003 to March 2005, we operated on 98 consecutive spinal disorders by using UBC, Sonopet UST-2001; Chiari type-1 malformation (6 cases), cervical disorders (64 cases), thoracic disorders (5 cases), and lumbar disorders (23 cases). The instrument was devoid of any spinning parts, and the risk of grabbing cotton pledgets and damaging normal tissue was thereby avoided. Support from assistants for irrigation and suction was not required.Findings. In this series, there were no iatrogenically induced injuries for example, direct or heat damage to surrounding soft tissues, including nerves, vessels, spinal cord, and dura matter. Considering potential complications of mechanical injuries by ultrasonic technique, intermittent usage and cotton protection during use under an operating microscope are recommended. We found that the ultrasonic device is easy to handle; however, it is time consuming for removing a large amount of bone and ossified lesions. Therefore, we recommend the combined use of this method with standard drilling.Conclusions. This system appears to be versatile, safe, and efficient in spinal surgery and could be improved by the development of a better handpiece.

Wall imaging of cerebral aneurysms with a modified surface-rendering technique of spiral CT.

Summary¶ Background. There has been no detailed documentation of the advantages of three-dimensional (3D) wall imaging of cerebral aneurysms. The usefulness of such endoscopic images obtained with modified spiral computed tomography angiography (CTA) was therefore examined in comparison with conventional spiral CTA and digital subtraction angiography (DSA). Methods. Fifteen of 45 patients who underwent conventional spiral CTA in our department in the past 4 years, were further studied with a technical modification of surface-rendering reconstruction in spiral CT. Endoscopic images were obtained by regulating the lower and higher thresholds of spiral CT scans in processing. Digital subtraction angiography was also performed for 14 of the 15 patients. The 3D wall images of the cerebral aneurysms were assessed in comparison with findings from conventional CTA and DSA. Findings. The true orifice of the aneurysms could be visualized with the endoscopic mode in all of the 15 cases. In paraclinoid aneurysms, particularly below the anterior clinoid process, the relationships to associated vessels and bone structures were more clearly disclosed with this mode. The endoscopic images of aneurysms with rigid clots or neighboring distended veins were not as adversely affected as conventional CTA. In 4 of the 15 the wall imaging precisely located the branches arising from the dome of aneurysms which DSA could not. Interpretation. Wall imaging of complex or small cerebral aneurysms provided valuable information on their relationships to associated arteries and surrounding bony structures. The endoscopic mode, a simple modification of surface rendering, is easily available in commercial CT processing packages.

Value of 3D CTA in association with accessory anterior cerebral artery with ruptured anterior communicating artery aneurysm.

An accessory anterior cerebral artery (ACA) sometimes makes it di‰cult to identify the structure of the anterior communicating artery (ACoA) complex, only with digital subtraction angiography (DSA) can it be clearly demonstrated. We report a case of a 67-yearold woman with subarachnoid haemorrhage due to ruptured ACoA aneurysm associated with an accessory ACA, which was found clearly in images of three dimensional computerized tomographic angiography (3D CTA). The images of 3D CTA for an accessory ACA have never been previously described.

Intradural Disk Herniation Mimicking a Spinal Tumor: Radiologic Imaging, Pathogenesis, and Operative Management

Intradural disk herniation (IDH) is a rare condition, occurring more often at the L4-5 level. We examined a case of an IDH at the L1-2 level mimicking an intradural spinal tumor. A 71-year-old woman with a long history of backache and pain radiating down the left leg was admitted to our hospital with the worsening of these symptoms. Magnetic resonance imaging and computed tomographic myelography demonstrated an intradural mass at the L1-2 level. Given the radiologic findings and the location of the mass, the preoperative differential diagnosis centered on intradural spinal tumors. Dural incision was performed using a surgical microscope to resect the mass. Contrary to our expectation, the diagnosis made during the surgery was IDH. Despite advances in imaging techniques, IDH could not be definitively diagnosed preoperatively. The pathogenesis of IDH remains unclear. In our patient, the ventral dural defect was smooth and round, and the dural tissue around the defect was thickened. These intraoperative findings suggested that the patients IDH resulted not from an acute new event but from a chronic process. We recommend dural incision using a surgical microscope for treating IDH because it provides a clear visual field.

Course of the Hemorrhagic Type Moyamoya Disease: Based on the Data of Re-hemorrhage and Collateral Circulation

We analyzed the effect of superficial temporal to middle cerebral artery (STA-MCA) bypass to prevent future strokes based on the data of the clinical course and the course of the collateral circulation. Thirty-five patients with hemorrhagic type moyamoya disease were examined during the follow-up period with a mean of 6.3 years after the initial intracranial hemorrhage. Eighteen patients were conservatively managed, 12 patients underwent STA-MCA bypass, and the last 5 patients underwent encephaloduroarteriosynangiosis (EDAS). The ophthalmic artery flow was examined as the collateral circulation using the color Doppler flow imaging (CDFI). During the follow-up period, 13 patients (43%, 5.86%/patient/year) experienced a cerebral event such as ischemia or rebleeding. The incidence of a future stroke event in the patients treated with STA-MCA bypass (ppp Clinical symptoms and ophthalmic artery CDFI findings confirmed that STA-MCA bypass in patients with hemorrhagic type moyamoya disease prevents future strokes.

Early Decompressive Surgery for Spinal Cord Injury: Rationale Based on Experimental Study

The use of hypothermia to treat patients with severe TBI was first reported by Fay in 1943, and Sedzimir in the 1950’s [1,2]. These clinicians thought that cooling patients to as low as 27°C for 1–5 days after injury led to better than expected outcomes in some patients. Lundberg reported that hypothermia was as effective as osmotic diuretics for reducing elevated ICP, and had a more prolonged effect than hyperventilation [3]. James et al found that hypothermia caused a reduction of ICP in at least half of 40 patients with severe TBI they studied, and that the average decrease associated with hypothermia treatment was 41% [4]. However, concerns about