Chikayuki Ochiai

EFFICACY OF CLOSED-SYSTEM DRAINAGE IN TREATING CHRONIC SUBDURAL HEMATOMA :A PROSPECTIVE COMPARATIVE STUDY

The authors conducted a prospective comparative study on the recurrence rate of chronic subdural hematoma after the use of two different treatment modalities: burr-hole irrigation of the hematoma cavity with (Group A) and without closed-system drainage (Group B). Thirty-eight patients were studied. Patients were assigned to groups sequentially upon admission. There were no significant differences between the two groups for age, sex, preoperative hematoma volume, and density on computed tomographic scan. One patient in Group A (5%) suffered a recurrence as opposed to 6 in Group B (33%). The difference in recurrence rate between the two groups was statistically significant (P less than 0.05). The authors conclude that closed-system drainage after burr-hole irrigation reduces the recurrence rate of chronic subdural hematoma.

Simulation of and training for cerebral aneurysm clipping with 3-dimensional models.

OBJECTIVEWith improvements in endovascular techniques, fewer aneurysms are treated by surgical clipping, and those aneurysms targeted for open surgery are often complex and difficult to treat. We devised a hollow, 3-dimensional (3D) model of individual cerebral aneurysms for preoperative simulation and surgical training. The methods and initial experience with this model system are presented. METHODSThe 3D hollow aneurysm models of 3 retrospective and 8 prospective cases were made with a prototyping technique according to data from 3D computed tomographic angiograms of each patient. Commercially available titanium clips used in our routine surgery were applied, and the internal lumen was observed with an endoscope to confirm the patency of parent vessels. The actual surgery was performed later. RESULTSIn the 8 prospective cases, the clips were applied during surgery in the same direction and configuration as in the preoperative simulation. Fine adjustments were necessary in each case, and 2 patients needed additional clips to occlude the atherosclerotic aneurysmal wall. With these 3D models, it was easy for neurosurgical trainees to grasp the vascular configuration and the concept of neck occlusion. Practicing surgery with these models also improved their handling of the instruments used during aneurysm surgery, such as clips and appliers. CONCLUSIONUsing the hollow 3D models to simulate clipping preoperatively, we could treat the aneurysms confidently during live surgery. These models allow easy and concrete recognition of the 3D configuration of aneurysms and parent vessels.

Postoperative contrast enhancement in brain tumors and intracerebral hematomas: CT study.

Postcontrast cerebral CT was performed sequentially on days 3, 7, and 14 after surgery in 34 patients [11 with gliomas; 6 with metastatic tumors, and 17 with intracerebral hematomas (ICH)]. The purpose of this study was to investigate the natural course and mechanisms of postoperative contrast enhancement (CE) of the brain around the removed lesions. Contrast enhancement was noted on days 3-14 in 10 patients in whom the gliomas were partially or subtotally removed. The intensity of CE appeared to increase with time. Among the six patients in whom the metastatic tumors were totally removed, four showed no CE until day 14 after surgery. Contrast enhancement appeared on day 3 in one and on day 14 in another. In 12 patients with ICH, which had been evacuated during the first 5 days after hemorrhage, CE was not noted on day 3 but began to appear on day 7, and intensified on day 14 after surgery. Contrast enhancement was demonstrated on day 3 in four of the five patients in whom the ICH was removed later than 10 days after the hemorrhage. No CE was observed on days 3 through 14 in the one patient in whom the hematoma capsule was totally removed. The present study suggests that CE noted on day 3 after removal of gliomas and metastatic tumors seems to be caused by extravasation of contrast medium within the residual tumor, which is devoid of blood-brain barrier. Contrast enhancement noted in ICH cases and intensifying CE noted in tumors 7 days after surgery seems likely to be caused by neovascularization in the postoperative brain.

Reinforcement of pericranium as a dural substitute by fibrin sealant

BackgroundFor dural plasty, several kinds of substitute materials are used clinically. Among these materials, pericranium is often used as a dural substitute since it is autologous and easy to harvest. However, it is rather thin and fragile, which makes it difficult to suture onto peripheral dura mater, especially when the defect is large.ObjectiveWe present a simple method of reinforcing the pericranium with fibrin sealant, which facilitates easier handling and suturing of the pericranium.MethodsFifteen patients who underwent surgical removal of meningioma, metastatic brain tumor and glioma attached to the dura mater were included in this analysis. To close the defects, we use ‘fibrin-sealed pericranium’. Herein we describe the method we employed in these cases. First, a standard skin flap is made by dissecting the subgaleal layer, leaving the periosteum on the bone. Second, fibrin sealant is evenly applied to the pericranium. Finally, the pericranium is cut along the reinforced area and dissected from the bone. The harvested pericranium is then used for closure of the dural defect. Some of these patients received further treatment as needed according to each pathology. The fibrin-sealed pericranium was examined histopathologically.ResultsFibrin-sealing of pericranium made it durable enough to be handled and sutured easily. There were no significant complications or treatment failures, such as infection or CSF leakage.ConclusionsReinforcement of the pericranium with fibrin sealant is a simple and easy method to reduce the stress of dural plasty.

A Novel Method for Transcranial Doppler Microembolic Signal Monitoring at the Vertebrobasilar Junction in Vertebral Artery Dissection Patients

Vertebral artery dissection (VAD) is one of the most important etiologies in young stroke patients. VAD causes ischemic stroke by embolism and transcranial Doppler (TCD) monitoring can detect microemboli originating from the dissection point as high intensity transient signals (HITS). We developed a simple but novel method of TCD monitoring at the vertebrobasilar junction in VAD patients.

Effectiveness of zigzag Incision and 1.5-Layer method for frontotemporal craniotomy.

Background: In this era of minimally invasive treatment, it is important to make operative scars as inconspicuous as possible, and there is a great deal of room for improvement in daily practice. Zigzag incision with coronal incision has been described mainly in the field of plastic surgery, and its applicability for skin incision in general neurosurgery has not been reported. Methods: Zigzag incision with 1.5-layer method was applied to 14 patients with unruptured cerebral aneurysm between April 2011 and August 2012. A questionnaire survey was administered among patients with unruptured aneurysm using SF-36v2 since April 2010. The results were compared between patients with zigzag incision and a previous cohort with traditional incision. Results: There were no cases of complications associated with the operative wound. In the questionnaire survey, all parameters tended to be better in the patients with zigzag incision, and role social component score (RCS) was significantly higher in the zigzag group than in the traditional incision group (P =0.0436). Conclusion: Zigzag incision using the 1.5-layer method with frontotemporal craniotomy seems to represent an improvement over the conventional curvilinear incision with regard to cosmetic outcome and RCS.

Development of a New Compact Intraoperative Magnetic Resonance Imaging System: Concept and Initial Experience

BACKGROUND: Magnetic resonance imaging (MRI) during surgery has been shown to improve surgical outcomes, but the current intraoperative MRI systems are too large to install in standard operating suites. Although 1 compact system is available, its imaging quality is not ideal. OBJECTIVE: We developed a new compact intraoperative MRI system and evaluated its use for safety and efficacy. METHODS: This new system has a magnetic gantry: a permanent magnet of 0.23 T and an interpolar distance of 32 cm. The gantry system weighs 2.8 tons and the 5-G line is within the circle of 2.6 m. We created a new field-of-view head coil and a canopy-style radiofrequency shield for this system. A clinical trial was initiated, and the system has been used in 44 patients. RESULTS: This system is significantly smaller than previous intraoperative MRI systems. High-quality T2 images could discriminate tumor from normal brain tissue and identify anatomic landmarks for accurate surgery. The average imaging time was 45.5 minutes, and no clinical complications or MRI system failures occurred. Floating organisms or particles were minimal (1/200 L maximum). CONCLUSION: This intraoperative, compact, low-magnetic-field MRI system can be installed in standard operating suites to provide relatively high-quality images without sacrificing safety. We believe that such a system facilitates the introduction of the intraoperative MRI. ABBREVIATIONS: FLAIR, fluid-attenuated inversion recovery FOV, field of view RF, radiofrequency