Yasushi Motoyama

Early Inhibition of Natriuresis Suppresses Symptomatic Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage

Background: Hyponatremia is a common complication occurring in one third of patients after subarachnoid hemorrhage (SAH). One mechanism that likely mediates the development of hyponatremia in SAH is cerebral salt wasting syndrome (CSWS), which induces natriuresis and reduces total blood volume, resulting in a risk of symptomatic vasospasm (SVS). The mineral corticoid fludrocortisone acetate enhances sodium reabsorption in the renal distal tubules and may help prevent post-SAH hyponatremia. However, management with fludrocortisone acetate is ineffective if hyponatremia is advanced, because CSWS and subsequent SVS develop rapidly. Therefore, an additional earlier marker is required to predict the development of hyponatremia for the initiation of immediate treatment in select patients. However, no conclusive evidence exists showing that hyponatremia influences the risk of SVS, and no standard treatment protocol exists for treating hyponatremia in patients with SAH. This study was undertaken to evaluate whether selective early treatment of hyponatremia prevents SVS in patients with increased urinary sodium excretion in the early phase following SAH. Methods: A total of 103 patients with aneurysmal SAH were managed for a postoperative electrolyte disorder after aneurysmal clipping or coil embolization. Between 2004 and 2007 (period 1), 54 patients started treatment to correct the electrolyte disorder after hyponatremia had occurred. Between 2007 and 2011 (period 2), 49 patients were prospectively subjected to sodium replacement treatment according to their daily sodium balance, and inhibition of natriuresis with fludrocortisone acetate was initiated just after an increase in urinary sodium excretion >300 mEq/day. The occurrence of hyponatremia, SVS, and outcomes were compared between the two periods. Results: Hyponatremia was observed in 14 patients (26%) in period 1 and 7 patients (14%) in period 2. The incidence of fludrocortisone acetate administration was significantly higher, and initiation of electrolyte correction was significantly earlier, in period 2 patients. We observed a significant difference in the frequency of SVS, which occurred in 10 patients (18.5%) in period 1 and 3 patients (6.1%) in period 2. Both urinary sodium excretion and urine volume at day 7 were significantly different between the two periods. However, no significant difference was observed in overall outcome between the two periods. Conclusions: Early inhibition of natriuresis with fludrocortisone acetate before the occurrence of hyponatremia prevented SVS after aneurysmal SAH. Increased urinary sodium excretion in the early phase of SAH is a good indicator for the initiation of electrolyte correction with fludrocortisone acetate.

Influence of Diabetes Mellitus and Cigarette Smoking on Variability of the Clopidogrel-Induced Antiplatelet Effect and Efficacy of Active Management of the Target P2Y12 Reaction Unit Range in Patients Undergoing Neurointerventional Procedures

BACKGROUND Optimal antiplatelet inhibition is essential in patients undergoing neurointerventional procedures; however, variability in response to clopidogrel can contribute to thromboembolic and hemorrhagic complications. The present study evaluated the influence of diabetes mellitus and cigarette smoking on clopidogrel reactivity. METHODS Between 2011 and 2013, 71 consecutive patients underwent aneurysmal coil embolization (CE) or carotid artery stenting (CAS) and received clopidogrel (75 mg daily) and aspirin (100 mg daily) before the treatment. The patients were divided into 2 groups: CE (n = 31) and CAS (n = 40). The patients underwent prospective assessment of preoperative platelet function using VerifyNow assay and received adjunctive cilostazol (200 mg daily, triple antiplatelet therapy) in case of clopidogrel hyporesponse. Patients with clopidogrel hyper-response underwent clopidogrel dose reduction (clopidogrel, 12.5-50 mg daily). RESULTS Clopidogrel resistance was noted in 15 patients (37.5%) in the CAS group and in 4 patients (12.9%) in the CE group (P = .031). Clopidogrel hyper-response was noted in 2 patients (5%) in the CAS group and in 11 patients (54.8%) in the CE group (P < .001). There was a significant difference in the baseline clinical characteristics between the 2 groups. In the multivariate logistic regression analysis, diabetes and age were independent predictors of clopidogrel hyporesponse, whereas current smoker was an independent predictor of clopidogrel hyper-response. CONCLUSIONS Significant differences in baseline clinical characteristics were present when comparing patients undergoing endovascular treatment of unruptured cerebral aneurysms and carotid artery stenosis. Diabetes mellitus and current smoker status were independent factors related to reactivity to clopidogrel.

Enhanced cerebral ischemic lesions after two-vein occlusion in diabetic rats

The two-vein occlusion (2VO) model is known to be useful for ischemic penumbra studies in vivo. It was applied here to examine sequential changes of regional cerebral blood flow (CBF) and cerebral venous infarction in normal (Long-Evans Tokushima Otsuka, LETO) and diabetic (Otsuka Long-Evans Tokushima Fatty, OLETF) rats. The aim of our study was to examine and compare the ischemic pathogenesis related to regional changes in cerebral blood flow (CBF) induced with 2VO in diabetic OLETF and non-diabetic LETO rats. Two cortical veins were occluded photochemically by using rose bengal dye in 10 OLETF and 10 LETO rats. All animals were killed with perfusion fixation at 48 h after 2VO. Bax and Bcl-2 staining was performed along with the terminal deoxynucleotidyl transderase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay to examine the relationship to single-cell death. Smooth muscle actin and Van Giesons elastic staining were done for assessment of thickening of the vessel walls. Not only the volume of cerebral cortex affected by 2VO-induced venous infarction was increased in diabetic OLETF rats, but we also observed significantly reduced CBF at 90 min after 2VO, coupled with increased apoptosis in and around ischemic lesions. Morphologically, OLETF rats demonstrated marked thickening of the walls in the small cerebral vessels with perivascular fibrosis, indicating more severe cerebral microvascular atherosclerotic changes as compared to their non-diabetic LETO counterparts. The OLETF rat thus appears to be an excellent animal model for studying the diabetic enhancement of venous ischemia induced by 2VO.

Effectiveness of a new gelatin sealant system for dural closure

Abstract Objectives: Watertight dural closure is imperative after neurosurgical procedures because inadequately treated leakage of cerebrospinal fluid (CSF) can have serious consequences. In this study, the authors test the use of a new gelatin glue as a dural sealant in in vitro and in vivo canine models of transdural CSF leakage. Methods: The in vitro model was sutured semicircles of canine dura mater and artificial dural substitute. The sutures were sealed with gelatin glue (n  =  20), fibrin glue (n  =  20), or a polyethylene glycol (PEG)-based hydrogel sealant (n  =  20). Each sample was set in a device to measure water pressure, and pressure was increased until leakage occurred. Bonding strength was subjectively evaluated. The in vivo model was dogs who underwent dural excision and received either no sealant (control group; n  =  5) or gelatin glue sealant (n  =  5) before dural closure. Twenty-eight days post-surgery, the maximum intracranial pressure was measured at the cisterna magna using Valsalva maneuver and tissue adhesion was evaluated. Results: The water pressure at which leakage occurred in the in vitro model was higher with gelatin glue (76·5 ± 39·8 mmHg) than with fibrin glue (38·3 ± 27·4 mmHg, P < 0·001) or the PEG-based hydrogel sealant (46·3 ± 20·9 mmHg, P  =  0·007). Bonding strength was higher for the gelatin glue than fibrin glue (P < 0·001) or PEG-based hydrogel sealant (P  =  0·001). The maximum intracranial pressure in the in vivo model was higher for the gelatin glue group (59·0 ± 2·2 mmHg) than the control group (13·8 ± 4·0 mmHg, P < 0·001). Tissue adhesion was lower for the gelatin glue group than the control group (P  =  0·005). Discussion: The new gelatin glue provides an effective watertight closure when used as an adjunct to sutured dural repair.

Rheumatoid arthritis-induced lateral atlantoaxial subluxation with multiple vertebrobasilar infarctions.

Study Design. Case report. Objective. To highlight the probability that lateral atlantoaxial subluxation (AAS) exists in patients with rheumatoid arthritis (RA) and induces vertebrobasilar infarctions that are more foregrounded than compressive myelopathy. Summary of Background Data. Although lateral subluxation is a well-known subtype of AAS, a case of cerebral ischemia associated with lateral AAS has not been reported before. Methods. A 52-year-old male with a 6-year history of RA had a sudden onset of visual field defect and mild right cerebellar ataxia. Head magnetic resonance imaging revealed acute multiple infarctions in the vertebrobasilar area, and magnetic resonance angiography revealed stenosis of the left vertebral artery (VA). Lateral radiograph of the cervical spine in the neutral position revealed atlanto-occipital assimilation and anterior AAS. T2-weighted sagittal images on cervical magnetic resonance imaging revealed high signal intensity in the spinal cord at C1–C2. Cerebral angiography revealed right VA occlusion and severe stenosis of the left V3 segment of VA. Three-dimensional computed tomography angiography of the craniovertebral junction revealed lateral AAS, which was due to severe erosive changes of the facet joints, and the left V3 portion was stenosed by a bony component. During conservative therapy, the patient experienced left occulomotor nerve palsy due to a second stroke. Results. Two months later, the patient underwent occipitocervical posterior fusion with an iliac bone graft. His postoperative course was uneventful, and the left VA stenosis disappeared. At the 45-month follow-up, he had no further infarctions. Bony fusion was radiologically confirmed, and 3-dimensional computed tomography angiography revealed good patency of the affected left VA. Conclusion. In patients with RA, the potential risk of AAS should be recognized. Lateral AAS in particular may induce cerebral ischemia by positional VA occlusion in advanced stages of the disease. Level of Evidence: N/A

Effectiveness of intraoperative indocyanine green videoangiography in direct surgical treatment of pediatric intracranial pial arteriovenous fistula

Intracranial pial arteriovenous fistulas (AVFs) are rare cerebrovascular lesions. The authors report a rare case of pediatric pial AVF treated by direct disconnection with the aid of indocyanine green (ICG) videoangiography. A 3-year-old girl presented with developmental problems. Magnetic resonance imaging revealed brain atrophy and an anomalous left temporal vascular mass. Angiography showed a high-flow pial AVF in the early arterial phase fed by the M1 portion of the left middle cerebral artery and draining into the superficial sylvian vein and the vein of Trolard with a large varix. Given that her fistula was located in a superficial region that was easily accessible by craniotomy, the authors successfully disconnected her pial AVF by direct surgery aided by ICG videoangiography, which clearly confirmed the shunting point. In this report, the authors discuss the existing literature and compare the relative merits of endovascular versus surgical options for the treatment of pial AVF.

Visualization of Regional Cerebral Blood Flow Dynamics during Cortical Venous Occlusion using Laser Speckle Contrast Imaging in a Rat Model

BACKGROUND Cerebral venous ischemia (CVI) is a rare but potentially significant complication of neurosurgical procedures. However, it is still unclear how cerebral venous occlusion (VO) affects regional cerebral blood flow (rCBF) dynamics. To elucidate its pathophysiology in detail, we examined the real-time perfusion dynamics during adjacent vein occlusions using laser speckle contrast imaging (LSCI) in a rat 2-vein occlusion model. METHODS Two cortical veins were occluded photochemically using rose Bengal dye in 6 male Wistar rats; rCBF was measured in real time with an LSCI before and after VO. Regions of interest were defined between the 2 veins (A) and on the opposite side of the first occluded vein (B) on semi-quantitative pseudocolor images for off-line analysis. Histopathologic evaluation was performed 3 days after the procedure to assess the extent of infarction. RESULTS LSCI revealed a stepwise reduction in CBF, with a sudden decrease just after the first vein occlusion (~20%) and a further decrease after the second (~30%). Significant differences were observed between rCBF dynamics within regions of interest A and B (P = .0004). All rats exhibited infarcts in the superficial cerebral cortex histopathologically. CONCLUSIONS This is the first report of LSCI specifically applied to the study of CVI. The extensive real-time measurement with high temporal and spatial resolution revealed the stepwise reduction in rCBF during sequential VO and the ensuing infarcts.

A magnetic resonance imaging technique to evaluate tumor-brain adhesion in meningioma: brain-surface motion imaging.

OBJECTIVE We examined the effectiveness of a newly developed magnetic resonance imaging (MRI) technique, brain surface motion imaging (BSMI), in the preoperative evaluation of tumor-brain adhesion in meningioma surgery. METHODS Cine phase-contrast MRI was used to measure cerebrospinal fluid (CSF) pulsations and heart rates at 2 different time points to create a subtraction image in meningioma patients who underwent BSMI. With no tumor-brain adhesion, a gap was observed in the tumor-brain movements, resulting in an outline of the tumor in BSMI. If adhesion was evident, no outline was observed. Cases were evaluated as exact if the presence or absence of edema in T2-weighted MRI, BSMI findings, and intraoperative findings all matched; as effected when only BSMI findings and intraoperative images matched; and as false when BSMI findings and intraoperative findings did not match. RESULTS BSMI judged 27 patients as adhesion (+) and 33 as adhesion (-), whereas surgical findings evaluated 22 as adhesion (+) and 38 as adhesion (-). The sensitivity and specificity were both high, at 95.5% and 84.2%, respectively. Forty-one of 60 patients were evaluated as exact, 12 as effected, and 7 as false. World Health Organization tumor grade assessment of effected subjects included 16.7% in grade 1 and 36.4% in grade 2. CONCLUSIONS BSMI was shown to be effective in evaluating adhesion between the meningioma and the brain, allowing safe and effective removal planning to be carried out preoperatively.

Surgical Management of Minimally Invasive Anterior Lumbar Interbody Fusion With Stand-Alone Interbody Cage for L4-5 Degenerative Disorders: Clinical and Radiographic Findings

Surgical treatment for degenerative spinal disorders is controversial, although lumbar fusion is considered an acceptable option for disabling lower back pain. Patients underwent instrumented minimally invasive anterior lumbar interbody fusion (mini-ALIF) using a retroperitoneal approach except for requiring multilevel fusions, severe spinal canal stenosis, high-grade spondylolisthesis, and a adjacent segments disorders. We retrospectively reviewed the clinical records and radiographs of 142 patients who received mini-ALIF for L4-5 degenerative lumbar disorders between 1998 and 2010. We compared preoperative and postoperative clinical data and radiographic measurements, including the modified Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score for back and leg pain, disc height (DH), whole lumbar lordosis (WL), and vertebral wedge angle (WA). The mean follow-up period was 76 months. The solid fusion rate was 90.1% (128/142 patients). The average length of hospital stay was 6.9 days (range, 3–21 days). The mean blood loss was 63.7 ml (range, 10–456 ml). The mean operation time was 155.5 min (range, 96–280 min). The postoperative JOA and VAS scores for back and leg pain were improved compared with the preoperative scores. Radiological analysis showed significant postoperative improvements in DH, WL, and WA, and the functional and radiographical outcomes improved significantly after 2 years. The 2.8% complication rate included cases of wound infection, liquorrhea, vertebral body fractures, and a misplaced cage that required revision. Mini-ALIF was found to be associated with improved clinical results and radiographic findings for L4-5 disorders. A retroperitoneal approach might therefore be a valuable treatment option.

Indocyanine Green (ICG) Videoangiography-Guided Dissection of the Sylvian Fissure on the Transsylvian Approach: Technical Note

BACKGROUND The transsylvian approach is a standard method of approach for anterior circulation aneurysms or paraclinoid tumors. Care must be taken, however, to avoid inadvertent obliteration of sylvian veins to prevent postoperative brain swelling and venous infarction. Sometimes, the superficial sylvian veins have complex connections or are not visible because of the thickness of the arachnoid membrane, especially in the case of subarachnoid hemorrhage (SAH). The present report describes a simple method to dynamically visualize the sylvian vein via indocyanine green (ICG) angiography for the purposes of appropriately wide dissection of the sylvian fissure. METHODS Before dissection of the sylvian fissure and after opening the dura mater, a bolus of ICG is administered intravenously. ICG videoangiography is used for dynamic venography at 10 seconds after the depiction of branches of the middle cerebral artery. RESULTS Clear documentation of the sylvian vein was obtained via ICG videoangiography, even in cases of SAH with ambiguous anatomical topography attributable to clot under the superficial arachnoid membrane. ICG was able to differentiate between the sylvian veins of the frontal and temporal lobes, which allowed wide dissection of the sylvian fissure while preserving the veins. CONCLUSIONS ICG videoangiography is an easy and useful method for identifying the connections and tributaries of the superficial sylvian veins from a transsylvian approach. This method allows wide opening of the sylvian fissure while preserving the sylvian veins.