Growth of a cerebral aneurysm may cause adhesion to surrounding structures. The procedure to detach a cerebral aneurysm from surrounding structure plays a crucial role in implementing an appropriate clipping strategy for aneurysmal surgery. Structures that adhere to the aneurysm can include major arteries, perforating arteries, veins, dura mater, brain tissue and clot. Adherent structures can thus be divided into two categories : vessels and other structures. Among frequently encountered situations, adhesion to vessels is one of the most problematic. In this case, fibrous adhesion shows characteristics of being tight at the margins, but loose in the center. In dissecting between the cerebral aneurysm and fibrous adhesion, making the most of this characteristic is important. First, dissect the loose adhesion in the center using jeweler's forceps to make space. Second, pinch the tight adhesion at the margin to emboss the fibrous adhesion. Finally, sharply incise the embossed fibrous adhesion with micro-scissors. Repeating these steps allows detachment of the adhesion with the aneurysm. Other structures such as adhered brain tissue, clots and dura mater may require complete exposure of the aneurysm to ascertain surrounding perforating arteries and cranial nerves. Utilizing a suction tube and brain retractor with appropriate pressure is essential for exposing the correct dissecting layer. In addition, retracting the brain, vessels, and sometimes the aneurysm itself is important to stabilize and enabling exposure of the correct layer. With a ruptured aneurysm, dissecting circumferentially while leaving the brain tissue and clot attached at the rupture site is important to avoid intraoperative rupture. In this article, we discuss and introduce practical methods for dissecting the structures surrounding cerebral aneurysms.

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  A well planned treatment strategy as well as a high level of surgical skill is necessary to accomplish cerebral arteriovenous malformation (AVM) surgery successfully. In this paper, we will discuss the standard strategy and surgical techniques when AVMs are treated by open surgery alone. First, careful planning based-on the preoperative 3-dimentional radiological examinations must be made. We also must prepare the operative instruments and seek the assistance of another neurosurgeon for relief support. AVM removal surgery consists of the following 4 steps : (1) make a sufficient craniotomy and separate the cortical sulci to secure the proximal feeding artery, (2) coagulate and cut the feeding arteries just before going into the nidus, (3) dissect the nidus using the gliosis area as a margin and the vessels loop as a guidepost, and coagulate the feeding arteries coming from the deep area, (4) cut the drainer after confirming its appearance has changed into the color of venous blood and then remove the nidus. The surgical skills to achieve those 4 steps are a standard technique to master as a vascular neurosurgeon.

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  The ultimate purpose of meningioma surgery is to achieve total tumor removal and functional recovery without complications. Various steps are required for successful tumor removal including a thorough preoperative imaging study, preoperative embolization, intraoperative monitoring, suitable positioning and craniotomy, selection of surgical approach and surgical instruments. In order to improve the surgical outcome, we introduce our method to utilize the Sugita multipurpose head frame and rake retractor. Intraoperative head rotation of up to 35 degrees makes the surgical approach less irritable to the brain thanks to the use of gravitational force. Various methods manipulating the rake retractor enable rapid tumor eradication with minimal brain damage.

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  Safe and total glioma removal without loss of neurological function is still a challenge. Basic surgical strategies need to be based on a deep and precise knowledge of brain anatomy. Routine preoperative evaluations include contrast-enhanced MRI, 3D-CT angiography, and PET (FDG and methionine) followed by creation of fusion images using a neuronavigation system. Diffuse tensor image-based pyramidal tract tractography is useful in surgeries for tumor removal near the tract. Intraoperatively, in combination with neuronavigation, transcortical SEP is used to detect the central sulcus, and MEPs are monitored by stimulation on the precentral gyrus. In addition, direct bipolar stimulation in the white matter near the pyramidal tract is more reliable than transcortical derived MEPs. In this article, we illustrate two representative glioma cases : a glioma adjacent to the primary motor area and a glioma in the hippocampus. Intraoperative MRI is a powerful tool to update real-time anatomy and detect residual tumors especially when the navigation based on preoperative images becomes less useful due to brain shift.

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  Carotid endarterectomy (CEA) is recommended in symptomatic patients with >50% stenosis, and also recommended in asymptomatic patients with >60% stenosis. CEA is an essential surgical technique for young neurosurgeons to master. In this paper, I provide an outline of the CEA technique to be used according to the anatomical findings, including high position stenosis. Since carotid patch angioplasty is the preferred technique for primary closure, therefore, I describe in detail how to perform patch angioplasty.

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  The basic technique for endovascular treatment of intracranial aneurysms is putting as many detachable coils as possible through a single microcatheter. However, if the aneurysm has characteristics that are unsuitable for the basic technique, such as an irregular shape or wide neck then treatment requires an advanced technique. With the development of the hyper-compliant balloon, a balloon assisted method has been introduced. In this procedure, a single lumen non-detachable balloon is inflated in front of the aneurysm neck during coil embolization to avoid coil protrusion to the parent artery. Additionally, this procedure also affords management of intra-procedural rupture. Now, this balloon assisted technique can be widely used for both ruptured and unruptured aneurysms. However, even when the current balloon system can navigate to intracranial arteries safely, sometimes a double catheter method is safer and more useful for irregularly shaped aneurysms. This method creates a stable frame within the aneurysm by using multiple microcatheters, packed tightly together with the framing coil. Another recently developed and rapidly growing technique is the stent-assisted method. The development of self-expanding stents dedicated to intracranial use has significantly widened the applicability of endovascular therapy to many intracranial aneurysms that would otherwise have been untreatable by endovascular techniques alone. Stents provide structural support for coil embolization by preventing coil herniation in wide-necked aneurysms, allowing increased packing density, causing flow diversion, and potentially providing a scaffold for orifice endothelialization. Compared with the balloon-assisted method and multiple catheter method, stent-assisted embolization may have a much higher rate of ischemic complications due to its thrombogenicity and a need for prolonged antiplatelet therapy. Advanced techniques have greatly increased the indications for endovascular treatment of intracranial aneurysms. One of the limitations of these techniques is that they require using multiple devices in the same parent artery ; however, these advanced techniques are valuable in the treatment of irregularly shaped and wide-neck aneurysms.

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  Vertebral compression fractures (VCFs) are the most common form of osteoporotic fracture with significant morbidity. Osteoporotic VCFs are a major health concern owing to the increasing population of elderly people. These fractures have traditionally been treated with conventional therapies such as analgesics, bed rest and bracing. In the last few decades, vertebroplasty, and subsequently kyphoplasty, have emerged as minimally invasive treatment options. Balloon kyphoplasty (BKP) is a recent modification of percutaneous vertebroplasty that can be considered in those patients who do not respond to initial treatment.
  Between February 2011 and July 2011, 7 patients with pain refractory to conservative therapy underwent single-level kyphoplasty. We prospectively assessed the results of the kyphoplasties by clinical and radiological methods. We evaluated clinical outcome using the visual analog scale (VAS), Japanese Orthopedic Association (JOA) and Oswestry Disability Index (ODI) scores. Radiological measurements included anterior, middle and posterior vertebral body height, local kyphotic angle and sagittal vertical axis (SVA).
  All patients were female. The mean age was 77.7, with a range from 73 to 85. The fractures were located at the thoracolumbar junction, T12 : 5 cases, L1 : 2 cases, respectively. The length of conservative treatment ranged from 4 to 6 months (mean 4.7 months).
  The mean VAS pain score decreased from 7.4±1.1 before surgery to 2.5±3.2 after surgery (p=0.03). The mean JOA score increased from 11.8±5.8 before surgery to 17.8±4.2 after surgery (p=0.007). The mean ODI score decreased from 34.0±9.0 before surgery to 21.4±12.2 after surgery (p=0.007).
  The mean anterior height was 7.7±2.0 before treatment and 16.0±2.3 after treatment (p=0.007). The mean middle height was 8.7±2.6 before treatment and 15.7±1.4 after treatment (p=0.007). The mean posterior height was 25.0±2.1 before treatment and 25.8±2.6 after treatment (p=0.18).
  The mean preoperative and postoperative local kyphotic angle at VCF were 21.2±4.6° and 12.4±3.7°, respectively (p=0.007). The mean preoperative and postoperative SVA were 83.1±19.1 and 73.8±24.9, respectively (p=0.15).
  BKP demonstrated rapid back pain relief in all patients associated with statistically significant restoration of vertebral body height and improvement of local kyphosis. However, the angular reduction attained at the level of VCF did not translate to similar correction of overall sagittal alignment. Cement extravasation was not observed, nor were complications such as pulmonary embolism or spinal compression. Only one patient developed subsequent vertebral body fracture adjacent to treated vertebra one month after the procedure. In our experience, kyphoplasty was found to be an effective and safe alternative in the treatment of osteoporotic VCFs.

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  The causal relationship between cranial irradiation and the subsequent development of meningioma is well established. However, very few studies have reported the development of a meningioma at the site of a previous craniotomy, even in cases where the patient underwent cranial irradiation after resection of a brain tumor. We report a case of meningioma that developed at the same site where a craniotomy was performed for the resection of an arteriovenous malformation (AVM) 9 years after radiotherapy.
  The patient had been diagnosed with acute lymphoblastic lymphoma at the age of 2 years, for which he received chemotherapy followed by prophylactic cranial irradiation. At the age of 11 years, the patient was hospitalized because of an intracerebral hematoma caused by a ruptured AVM. He underwent an uneventful resection of the AVM, and an artificial dura capable of inducing granulomatous reaction as a foreign body was used. At the age of 22 years, he presented with right arm numbness. The magnetic resonance imaging (MRI) scan showed a large well-defined mass in the left parietal region, where an AVM had been resected previously. The tumor was completely removed, and pathological examination had revealed that the tumor was a meningothelial meningioma without malignant features. The postoperative course was uneventful, and MRI performed 1 year after surgery revealed no signs of recurrence. In addition to irradiation, extrinsic etiological factors such as surgical trauma and chronic inflammation might have led to the development of a meningioma at the same site of the previous craniotomy.

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