Haptoglobin (Hp) allele heterogeneity has been implicated in differential reactive oxidant inhibition and inflammation. Association of 3 major subtypes of Hp, Hp1-1, Hp2-1, and Hp2-2, may be based on functional differences between Hp1 and Hp2 in hemoglobin binding and its rate of clearance from serum. The Hp genotype has been shown to be a predictor of clinical outcomes in aneurysmal subarachnoid hemorrhage (aSAH). Furthermore, a common single nucleotide polymorphism, rs2000999, located in an Hp-related gene is reportedly a strong genetic predictor of serum Hp levels. We investigated the usefulness of serum Hp level and rs2000999 genotype as markers for prediction of clinical outcome after aSAH prospectively. Ten patients with good outcome (35.7%), in a total of 28 patients (23 female) ranging from 36 to 87 years of age (mean: 64.3 years), showed trends of higher serum Hp levels compared to other patients with poor outcomes (64.3%) at day 0 (p = 0.08). G/A (85.7%) and A/A (50%) genotypes of rs2000999 were likely associated with poor outcome and higher severity than G/G (40%) in aSAH by about 5.2 fold. In conclusion, the results of this study suggested that the serum Hp level and rs2000999 genotype will be useful as genetic biomarkers for predicting the clinical outcome of aSAH.

The transsylvian approach is a popular technique in neurosurgery, but surgical dissection of the sylvian fissure is often difficult. We report the usefulness of 3D digital subtraction venography for surgical planning of sylvian fissure dissection. In 3D digital subtraction venography, the injection rate was 3 ml/sec with a 6-second scan time and an x-ray delay time of 7 seconds. According to the 3D digital subtraction venography, the superficial sylvian vein was categorized into two patterns: the frontosylvian vein and the temporosylvian vein. This technique provided abundant working space with less brain retraction during aneurysm clipping.

Clipping procedures for anterior choroidal artery (AChA) aneurysms carry a greater risk than clipping of other aneurysms. Ischemic complications are the most common and serious events observed in AChA aneurysm treatment. The aim of this study was to compare the characteristics of AChA aneurysms with other aneurysms and to examine the causes of ischemic complications after surgical clipping for AChA aneurysms. We retrospectively reviewed clinical and radiological data of 519 consecutive patients who had undergone aneurysm clipping in our institute and intraoperative videos of 32 consecutive patients with AChA aneurysms. Branches arising from the aneurysmal dome (dome type) were more frequent with AChA aneurysms (18.8%) than with other types of aneurysm (3.7%, p<0.05). Symptomatic ischemia due to surgical clipping occurred in 1 case of AChA aneurysm (3.1%), representing very good outcomes. We suggest that the high frequency of dome type is a key contributor to the high rate of ischemic complications of AChA aneurysms. Fully grasping the course of AChA aneurysms and maintaining flow during surgical clipping is imperative.

In most patients with cerebral aneurysms of the peripheral portion of the anterior inferior cerebellar artery or posterior inferior cerebellar artery, selective endovascular aneurysmal obliteration is very difficult. Endovascular occlusion of the parent artery may be an easier approach, but this can have potentially unfavorable clinical consequences due to ischemic complications. Here we propose aneurysmal neck clipping with preservation of blood flow in the parent artery as an ideal firstline treatment for such lesions, although expertise in microsurgical techniques and anatomical knowledge are required.

The treatment of complex cerebral aneurysms, such as large/giant aneurysms, dissecting aneurysms, and recurrent aneurysms after endovascular therapy, is often challenging. Bypass procedures for the management of complex aneurysms could be a treatment option. We retrospectively reviewed patients with complex aneurysm who underwent bypass surgery between April 2006 and December 2016. The necessity of bypass was determined by balloon test occlusion (BTO) for all unruptured aneurysms. Ruptured/unruptured aneurysms were 5/21 cases, and high-flow bypass/lowflow bypass were 11/15 cases, respectively. Twenty of 21 patients with unruptured aneurysms showed a favorable outcome (modified Rankin Scale 0-2), while only 1 of 5 patients with ruptured aneurysms had a favorable outcome. In conclusion, the results of our surgical strategy for unruptured complex aneurysms under BTO algorithm were acceptable; however, the results of ruptured complex aneurysms had issues to be solved. To improve the safety of the treatment for complex aneurysms, bypass procedure is useful and sometimes mandatory.

Endovascular treatment is suggested as a useful intervention for distal posterior inferior cerebellar artery (PICA) aneurysms due to the anatomical environment specific to these aneurysms that can develop deep under the posterior fossa and are therefore associated with a higher risk of craniotomy. This study considered patients who received endovascular treatment for distal PICA aneurysms in our hospital. Thirteen patients with ruptured aneurysms were treated, including patients with saccular (n=8) and dissecting (n=5) aneurysms. Intra-aneurysmal embolization and parent artery occlusion were performed in seven and six patients, respectively. Radiological outcomes immediately after treatment included: complete occlusion (n=6; 46.2%), neck remnant (n=4), and body filling (n=3). Patients with complete occlusion increased to 11 (91.7%) during the follow-up period. Surgical complications included two intraoperative ruptures and four cerebellar infarctions resulting from parent artery occlusion. The Modified Rankin Scale score was good overall during follow-up: 0 in nine patients, 1 in two patients, 2 in one patient, and 6 in one patient. One patient had a recurrent aneurysm and required additional coil embolization. Re-bleeding was not observed during follow-up. These results further support coil embolization as an effective treatment for aneurysms and favorable patient prognosis in patients with distal PICA aneurysm.

Kissing aneurysms are defined as two adjacent aneurysms that have their own neck and partially adhere to each other. In our institution, we summarized these patients and four cases of ruptured kissing aneurysms were treated by endovascular treatment. Of the four, one originated from internal carotid-posterior communicating and ipsilateral internal carotid-anterior choroidal arteries and the remaining originated from distal anterior cerebral aneurysms. Three of the four cases were able to perform coil embolization from the same working angle of each other. All these cases were successfully treated by endovascular treatment without complications.

In the surgical treatment of kissing aneurysms, few reports suggested the usefulness of endovascular treatment. However, surgical clipping of kissing aneurysms warrants great caution due to lack of sufficient spaces around the aneurysmal neck than solitary aneurysm, and it is difficult to determine which aneurysm has bled and should be clipped first. The potential for premature rupture may be higher than ordinary aneurysm. On the other hand, endovascular treatment can be safely performed when the working angle of the aneurysmal neck is confirmed.

Purpose: Carotid artery stenting (CAS) reduces the risk of ischemic stroke in patients with carotid artery stenosis, although recent randomized trials showed an increase in periprocedural stroke risk in elderly patients undergoing CAS. Recently, the safety and efficacy of tailored-CAS was reported. We retrospectively compared the clinical results of tailored-CAS between patients >80 and <80 years old.

Materials and methods: From April 2013 to December 2016, 18 of 105 patients who underwent tailored-CAS at our hospital were ≥80 years old. The patients were examined by computed tomography angiography, magnetic resonance angiography, magnetic resonance imaging - black blood imaging, ultrasonography, and angiography before the procedure. The choice of embolus prevention procedure and stent type depended on lesion morphology and plaque characteristics. We analyzed the 30-day stroke risk, death rates, and diffusion-weighted imaging (DWI) positive rates between ≥80- and <80-year-old patients.

Results: The periprocedural stroke rate was 3.4% (3/87) in <80-year-old patients and 5.6% (1/18) in ≥80-year-old (p = 0.17). The incidence of new DWI lesions after CAS was 34/87 (39%) in <80-year-old patients, and 4/18 (22.2%) in ≥80-year-old patients (p = 0.67). No significant differences were observed between the two groups regarding periprocedural events and DWI-positive rates.

Conclusion: The tailored-CAS algorithm for selecting the most appropriate embolic protection device and stent, which is based on lesion morphology and plaque characteristics, may be useful in elderly patients with carotid stenosis.

Purpose: Acute subdural hematoma (ASDH) due to ruptured intracranial aneurysm, but without subarachnoid hemorrhage (SAH) or intracerebral hemorrhage (ICH), is extremely rare. We report a case of pure ASDH caused by intracranial aneurysm rupture and review the literature.

Case: A 41-year-old woman visited our hospital with complaints of severe headache. Magnetic resonance imaging and magnetic resonance angiogram (MRA) demonstrated an extensive ASDH (without SAH or ICH) at the bilateral convexity, tentorium, interhemispheric fissure, anterior fossa, middle fossa, posterior fossa, and clivus as well as from the foramen magnum to the spinal canal. The left internal carotid-posterior communicating artery (IC-PC) aneurysm was enlarged to 9 mm in diameter approximately. We diagnosed as pure ASDH due to the ruptured left IC-PC aneurysm, and treated it emergently.

Treatment: We performed coil embolization with a balloon-assisted technique, and treated the aneurysm twice because of coil compaction, and finally obtained complete occlusion. The patient recovered without any neurological deficits.

Discussion: Intracranial aneurysm rupture usually present as an SAH or ICH. ASDH is identified in 0.5%-7.9% of patients with ruptured intracranial aneurysms. Pure ASDH without SAH or ICH caused by intracranial aneurysm rupture is extremely rare, and only 50 such cases have been reported. Of the 51 cases (including our present case), the most frequent site of aneurysm in 26 cases (51.0%) was the IC-PC. The location of the ASDH was convexity in 29 cases (56.9%), and convexity + tentorium in 11 cases (21.6%). Good outcomes were reported in 35 cases (68.6%). Several mechanisms have been proposed to explain the occurrence of subdural hematoma after aneurysm rupture. (1) Minor bleeding from an aneurysm may cause adhesion to the arachnoid membrane, and the final rupture occurs directly into the subdural space. (2) Hemorrhage under high pressure may lacerate the arachnoid membrane and bleed into the subdural space. (3) Intracerebral bleeding may rupture through the cortex and lacerate the arachnoid membrane. The bleeding mechanism in our patient might be (1).

Conclusion: We treated a rare case of a ruptured intracranial aneurysm, demonstrated a pure ASDH. MRA, CT angiography and digital subtraction angiography should be performed to detect vascular abnormalities in patients who present with a pure ASDH without a history of trauma.

We herein report a case of a basilar superior cerebellar artery (BA-SCA) aneurysm treated with clipping via a contralateral pterional approach. A woman in her 60s with multiple aneurysms was admitted to our hospital. Three-dimensional computed tomography angiography (3DCTA) showed aneurysms of the bilateral middle cerebral artery (MCA), anterior communicating artery (A-com), left BA-SCA, and left distal posterior cerebral artery. The right MCA aneurysm and A-com aneurysm were greater than 5 mm in size, and neck clipping via a right pterional approach was scheduled. In this operation, the possibility of neck clipping of the contralateral left BA-SCA aneurysm was preoperatively investigated. The aneurysm was 3 mm in size, and the height of the aneurysm from the top of the posterior clinoid process was 8 mm. We employed an optico-carotid triangle as an access route to the aneurysm, because the right internal carotid artery was curved posterolaterally, creating a wide surgical working space in the triangle. In addition to these findings, we paid attention to the rotation of the BA apex and the ideal closure line of the aneurysmal neck. The BA apex rotated 18° to the right side. The ideal closure line was straight and rotated 13° to the right side. These findings were thought to contribute to the visibility of the contralateral left BA-SCA aneurysm. The left BA-SCA aneurysm was clipped successfully via a contralateral pterional approach.

Carotid free-floating thrombus (CFFT) is rare with less than 150-200 cases reported in the literature. Most previous reports were related to the spontaneous onset of CFFT. Its etiology was thought to be due to atheromatous plaque complication and hypercoagulable states. We experienced a longitudinally extensive CFFT secondarily generated following intravenous thrombolytic therapy. When reviewing the literature, there was only one other case of CFFT secondarily generated after intravenous thrombolytic therapy. Treatment options of CFFT include medical management and surgical and endovascular thrombectomy. In our case, mechanical thrombectomy was deferred due to an extremely high risk of embolism. Delayed endarterectomy after antithrombotic therapy resulted in a favorable clinical outcome. We report an extremely rare and successful case of longitudinally extensive CFFT, secondarily generated after intravenous thrombolytic therapy.