Hyon-Jo Kwon

Endovascular treatment of tandem vascular occlusions in acute ischemic stroke.

Background and purpose Tandem vascular occlusions are an important cause of acute ischemic stroke (AIS) and present unique treatment challenges. We report our experience of managing a subset of AIS patients with extracranial vascular stenting/angioplasty and intracranial revascularization. Methods Consecutive patients who presented at three centers with AIS from tandem vascular occlusions confirmed by brain and neck CT imaging were included in the study. We retrospectively analyzed the patient demographics, National Institute of Health Stroke Scale (NIHSS) score and modified Rankin Scale (mRS) score at the time of admission, treatment strategy, angiographic results using the Thrombolysis In Cerebral Infarction (TICI) score, and clinical and imaging follow-up. Results Twenty-eight patients were included. The mean NIHSS score at admission was 18. Extracranial carotid occlusions with a concomitant middle cerebral artery occlusion were seen in 89.3% of patients (n=25) and vertebral artery combined with basilar artery lesions in 10.7% (n=3). An antegrade approach (ie, treatment of the extracranial lesion first) was used in 24 patients (85.7%). Proximal occlusion recanalization was achieved usually with a stent (n=27; 96.4%). Pursuant to intracranial revascularization techniques, ≥TICI 2A recanalization was seen in 96.4% of patients. An mRS score of ≤2 at 90 days was achieved in 56.5% of patients. Conclusions Our study shows preliminary data from three centers on recanalization of tandem occlusions in patients presenting with AIS. There was a preference to revascularize the proximal occlusion using a stent followed by distal recanalization with mechanical thrombectomy, intra-arterial thrombolysis or a combination of these. This approach has low periprocedural complications and can achieve an excellent angiographic and clinical outcome.

Endovascular Mechanical Thrombectomy in Basilar Artery Occlusion: Initial Experience

Objective This study was conducted to assess the efficacy and safety of endovascular mechanical thrombectomy (EMT) for patients diagnosed with basilar artery (BA) occlusion. Materials and Methods We retrospectively analyzed clinical and imaging data of 16 patients diagnosed with BA occlusion who were treated with endovascular intervention from July 2012 to February 2013. Direct suction using the Penumbra system and thrombus retrieval by the Solitaire stent were the main endovascular techniques used to restore BA flow. The outcomes were evaluated based on rate of angiographic recanalization, rate of improvement of National Institutes of Health Stroke Scale (NIHSS) score, rate of modified Rankin Scale (mRS) at discharge and after 3 months, and rate of cerebral hemorrhagic complications. Successful recanalization was defined as achieving Thrombolysis In Cerebral Infarction (TICI) of II or III. Results Sixteen patients received thrombectomy. The mean age was 67.8 ± 11 years and the mean NIHSS score was 12.3 ± 8.2. Eight patients treated within 6 hours of symptom onset were grouped as A and the other 8 patients treated beyond 6 hours (range, 6-120) were grouped as B. Successful recanalization was met in six patients (75%) for group A and 7 (87.5%) for group B. Favorable outcome occurred in 4 patients (50%) for group A and 5 (62.5%) for group B. Conclusion Our study supports the effectiveness and safety of endovascular mechanical thrombectomy in treating BA occlusion even 6 hours after symptom onset.

Mechanical Thrombectomy Using a Solitaire Stent in Acute Ischemic Stroke; Initial Experience in 40 Patients

Objective This study was conducted in order to demonstrate the initial experience of the Solitaire AB stent in mechanical intracranial thrombectomy. Methods We conducted a retrospective review of 40 consecutive patients who underwent intra-arterial Solitaire AB stent thrombectomy for treatment of acute ischemic strokes between October 2010 and November 2011. Demographic, clinical, and radiological presentations and outcomes were studied. Results Twenty six men and 14 women with a mean initial National Institutes of Health Stroke Scale (NIHSS) score of 14.1 (range, 8-26) and a mean age of 65.4 (range, 32-89) years were included in this study. Occlusion sites were as follows: internal carotid artery (n = 11), middle cerebral artery M1 (n = 22), M2 (n = 5), and basilar artery (n = 2). Successful revascularization was achieved in 36 (90%) patients. The mean NIHSS score was 11.6 (range, 1-23) at 24 hours after the procedure, and 42.5% of patients showed a modified Rankin scale score of ≤ 2 at 90 days. New occlusion by migrated emboli was observed in one (2.5%) case. Post-procedural intracerebral hemorrhage occurred in only one case (2.5%), with an all-cause mortality of two (5%). Conclusion The Solitaire AB device is a relatively safe and effective tool for use in performance of mechanical thrombectomy in patients with acute ischemic stroke.

Multiple Extracranial Metastases of Atypical Meningiomas

Meningiomas are usually benign neoplasms in which extracranial metastases occur very rarely. We report a case of multiple extracranial metastases of an atypical meningioma following a local recurrence. A 68-year-old man presented with left-side motor weakness and dysarthria for two weeks. A computed tomography (CT) scan and magnetic resonance imaging (MRI) showed an intraventricular tumor. We performed a total mass removal, and the histopathologic findings were consistent with benign meningioma. Eight months later, the meningioma recurred. We performed a reoperation and whole brain radiation therapy postoperatively. The histopathologic findings showed atypical meningioma. Six months later, CT and MRI revealed metastases to multiple vertebrae, lung, ribs and perirenal soft tissue so a decompressive laminectomy with mass removal was performed. The histopathologic findings of the spinal tumors showed atypical meningioma. The results from perirenal biopsies were consistent with metastatic meningioma. In conclusion, extracranial metastasis as well as local recurrence must be considered in atypical or anaplastic meningioma. There must be regular follow-ups. Finally, an evaluation of the chest, abdomen and bone is necessary, especially when related symptoms or signs develop.

Early detachment of the Solitaire stent during thrombectomy retrieval: an in vitro investigation

Objective To elucidate the early detachment of the Solitaire stent during mechanical thrombectomy, we tested the stent in vitro under various conditions and evaluated with microscopy. Methods A total of five stents were tested. Using a dynamic mechanical analysis machine, we calculated the tensile force needed for separation of the four stents from the pusher wire. Stent Nos 1 and 2 were tested without any prior manipulation. During the retraction test, no sheathing around the stent–wire junction was applied to stent No 1 whereas stent No 2 was partially covered with a sheath in accordance with instructions for use (IFU) recommendations. Stent No 3 was tested after deployment and retrieval were performed three times in an in vitro vascular replica with sheathing during retrieval. Stent No 4 was tested after one deployment and retrieval using the same replica as in stent No 3 without sheathing. In addition, forward pushing force was applied intentionally during retraction to induce excessive bending of the stent. Stent No 5 was pulled apart by both hands. After separation, stent tips and pusher wires were studied for all stents under the microscope. Results The tensile force needed for separation was about 6 N for stent Nos 1, 2, and 3, and about 4 N for stent No 4. All of the stents showed separation at the proximal marker, not at the detachment zone. Conclusions Detachment of the Solitaire stent during thrombectomy can be due to separation around or inside the proximal marker. Adherence to the manufacturers IFU of partial re-sheathing during retraction and not using the device for more than two passes might decrease the possibility of such device failure.

Nafamostat mesilate promotes endothelium-dependent vasorelaxation via the Akt-eNOS dependent pathway.

Nafamostat mesilate (NM), a synthetic serine protease inhibitor, has anticoagulant and anti-inflammatory properties. The intracellular mediator and external anti-inflammatory external signal in the vascular wall have been reported to protect endothelial cells, in part due to nitric oxide (NO) production. This study was designed to examine whether NM exhibit endothelium dependent vascular relaxation through Akt/endothelial nitric oxide synthase (eNOS) activation and generation of NO. NM enhanced Akt/eNOS phosphorylation and NO production in a dose- and time-dependent manner in human umbilical vein endothelial cells (HUVECs) and aorta tissues obtained from rats treated with various concentrations of NM. NM concomitantly decreased arginase activity, which could increase the available arginine substrate for NO production. Moreover, we investigated whether NM increased NO bioavailability and decreased aortic relaxation response to an eNOS inhibitor in the aorta. These results suggest that NM increases NO generation via the Akt/eNOS signaling pathway, leading to endothelium-dependent vascular relaxation. Therefore, the vasorelaxing action of NM may contribute to the regulation of cardiovascular function.

Prediction of Chronic Subdural Hematoma in Minor Head Trauma Patients

Objective Chronic subdural hematoma (CSDH) is relatively common in neurosurgical field. However not all patients develop CSDH after minor head trauma. In this study, we evaluate the risk factors of post-traumatic CSDH. Methods Two-hundred and seventy-seven patients were enrolled and analyzed in this study from January 2012 to December 2013. Of those, 20 participants had minor head trauma developed CSDH afterward. We also included 257 patients with minor head trauma who did not develop CSDH during the same follow-up period as the control group. We investigated the risk factors related to the development of CSDH after minor head trauma. Results Old age (p=0.014), preexisting diabetes mellitus (p=0.010), hypertension (p=0.026), history of cerebral infarction (p=0.035), antiplatelet agents (p=0.000), acute subdural hematoma in the convexity (p=0.000), encephalomalacia (p=0.029), and long distance between skull and brain parenchyma (p=0.000) were significantly correlated with the development of CSDH after trauma. Multivariate analysis revealed that only the maximum distance between the skull and the cerebral parenchyma was the independent risk factor for the occurrence of CSDH (hazard ratio 2.55, p=0.000). Conclusion We should consider the possibility of developing CSDH in the post-traumatic patients with the identified risk factors.

Syringo-Subarachnoid-Peritoneal Shunt Using T-Tube for Treatment of Post-Traumatic Syringomyelia

Various surgical procedures for the treatment of post-traumatic syringomyelia have been introduced recently, but most surgical strategies have been unreliable. We introduce the concept and technique of a new shunting procedure, syringo-subarachnoid-peritoneal shunt. A 54-year-old patient presented to our hospital with a progressive impairment of motion and position sense on the right side. Sixteen years before this admission, he had been treated by decompressive laminectomy for a burst fracture of L1. On his recent admission, magnetic resonance (MR) imaging studies of the whole spine revealed the presence of a huge syrinx extending from the medulla to the L1 vertebral level. We performed a syringo-subarachnoid-peritoneal shunt, including insertion of a T-tube into the syrinx, subarachnoid space and peritoneal cavity. Clinical manifestations and radiological findings improved after the operation. The syringo-subarachnoid-peritoneal shunt has several advantages. First, fluid can communicate freely between the syrinx, the subarachnoid space, and the peritoneal cavity. Secondly, we can prevent shunt catheter from migrating because dural anchoring of the T-tube is easy. Finally, we can perform shunt revision easily, because only one arm of the T-tube is inserted into the intraspinal syringx cavity. We think that this procedure is the most beneficial method among the various shunting procedures.

Impacts of Rapid Recanalization and Collateral Circulation on Clinical Outcome after Intraarterial Thrombolysis

Background and Purpose Rapid recanalization might improve clinical outcomes after intraarterial thrombolysis (IAT) for acute ischemic stroke patients with collateral circulation. We determined whether rapid recanalization and collateral circulation affect clinical outcomes after IAT. Methods We retrospectively evaluated the clinical and radiological data of 134 consecutive patients who underwent IAT for intracranial artery occlusion. The interval from symptom onset to recanalization after IAT (onset-to-recanalization time) as an estimate of the probability of good clinical outcome (modified Rankin scale 0-2) was calculated in patients with collateral circulation in the ischemic hemisphere, which was rated poor (0/1 American Society of Interventional and Therapeutic Neuroradiology criteria) or good (2-4). Changes in National Institute of Health Stroke Scale (NHISS) score before and after IAT and modified Rankins scale scores 3 months after discharge were compared with respect to onset-to-recanalization time. Results In patients with good collateral circulation, the estimated onset-to-recanalization time for a 0.5 probability of a good clinical outcome was 347 minutes; with poor collateral circulation, it was 172 minutes for a 0.2 probability of good clinical outcome. Outcome analyses according to onset-to-recanalization time showed patients recanalized <6 hours had lower NHISS scores (<4.5, 4.5-6, >6 hours of onset-to-recanalization time, and non-recanalization: 5.1, 6.9, 11.9, and 19.8, respectively) at discharge and higher percentages of good clinical outcome (69%, 66.7%, 21.9%, and 0%, respectively) 3 months after IAT. Conclusions The time window to expect a high probability of a good clinical outcome after IAT is highly dependent on the collateral circulation.

Idiopathic Spinal Cord Herniation Presented as Brown-Sequard Syndrome : A Case Report and Surgical Outcome.

Spinal cord herniation is a rare condition that has become increasingly recognised in the last few years. The authors report a case of idiopathic spinal cord herniation in a 33 year old woman performed with progressive Brown-Sequard syndrome. The diagnosis was made on MR imaging. After repairing the herniation, the patient made a gradual improvement. Potential causes are discussed, including a possible role of dural defect. In conclusion, idiopathic spinal cord herniation is a potentially treatable condition that should be more readily diagnosed that increasing awareness and improved imaging techniques.