The three principles for the focus diagnosis of epilepsy are semiology, electroencephalography (EEG), and brain imaging. When applying seizure semiology to localization diagnosis, the concept of the symptomatogenic zone is crucial. The symptomatogenic zone may be the seizure onset region itself or an area in the vicinity of the seizure onset region. In seizure semiology, manifestations include positive and negative signs. Clinical-electrical-anatomical diagnosis is important to make a localization diagnosis of the epileptogenic region inferred from the semiology in combination with EEG and imaging studies. Understanding epilepsy semiology is also crucial for the diagnosing of non-epileptic seizures in practice. In this article, we discussed the differential diagnosing between syncope and epileptic seizures. Seizures with brief loss of consciousness are classified into absence seizures and focal impaired awareness seizures, with focal impaired awareness seizures often having temporal or frontal lobe onset. Differential diagnosis of these types of seizures is also presented. Symptoms of frontal lobe-onset seizures can be categorized into lateral, medial, and basal. The characteristics of insular onset seizures are also discussed.

  The precise delineation of the “epileptogenic zone” is crucial for resective epilepsy surgery. No single examination is adequate for delineating the zone partly, because it is included within the resected area in patients with a favorable postoperative seizure outcome. Preoperative estimation of the epileptogenic zone is conducted using a multidisciplinary approach. This diagnostic approach includes examinations, such as magnetic resonance imaging, fluorodeoxyglucose positron emission tomography, magnetoencephalography, and video-electroencephalographic monitoring with scalp or intracranial electrodes. Among these, intracranial electrode recording is an important method for precisely estimating the epileptogenic zone. In Japan, subdural grid electrodes have been used to examine epileptogenic zone and functional cortices following the clinical standards established in the United States during the 20th century. Stereotactic implantation of multiple depth electrodes (stereotactic electroencephalography : SEEG) is gaining popularity because it is less invasive and enables the exploration of deep structures. However, the concept of SEEG is quite different from that of subdural grids in terms of planning, procedure, interpretation of results, and subsequent resection strategy. Therefore, a thorough understanding of the characteristics of these two types of electrodes is needed to select the appropriate modality for each patient.

  It has been 10 years since the initiation of the first focused ultrasound treatment for essential tremor in Japan in 2013. With the advent of this treatment, we entered an era of three major functional neurosurgical treatments: stereotactic thalamic coagulation utilizing high-frequency waves, deep stimulation therapy, and stereotactic thalamic coagulation employing focused ultrasound. However, just as radiofrequency coagulation and deep stimulation therapy share similarities, they also have distinct differences, radiofrequency coagulation and ultrasonic coagulation also present disparities. Paradoxically, the convergence itself is a current problem. It is imperative to be familiar with the hazards of diffuse ultrasound and to enhance efficacy and safety by creating convergence and proper coagulation. The principle of focused ultrasound therapy and its shape characteristics will be introduced, considering the current issues.

  Microvascular decompression (MVD) is a standard procedure for treating trigeminal neuralgia (TN). Several vascular or bony obstacles interfere with the microscopic visualization of suboccipital retrosigmoid craniotomy. The suprameatal tubercle (SMT), a bony prominence of variable size located above the internal acoustic meatus, is one such obstacle. When an SMT is too large to enable inspection of the entire trigeminal length, from the root entry zone to Meckel's cave, during MVD, removal of the SMT may be required to allow sufficient exposure of the neurovascular conflict (NVC) site on the trigeminal nerve. The authors encountered 20 such cases among 200 patients who underwent MVD for TN at our institute over a period of seven years (2011-2017). Based on these surgical experiences, they conducted an analysis of the patients' clinical characteristics, SMT height, operative findings, and surgical outcomes. Patients who required SMT removal were significantly younger (53.0 vs. 64.5 years ; p=0.0014) and had significantly larger SMT heights (5.7 vs. 3.8 mm; p＜0.0001) than those of the patients who did not require SMT removal. The detailed surgical procedures involved the following steps: (1) skeletonization of the superior petrosal vein complex via meticulous dissection of the arachnoid membrane; (2) careful resection of the SMT using a high-speed drill or an ultrasonic aspirator, while protecting surrounding neurovascular structures to avoid mechanical or thermal injury;and (3) resolution of the NVC through a routine decompression method after a thorough inspection of the offending vessels throughout the entire neural length, followed by sealing of the surface of the drilled petrous edge with bone wax or muscle pieces to minimize the risk of cerebrospinal fluid leakage, as necessary. The removal of SMT enabled a safe MVD, providing improved exposure of the NVC site. Surgical outcomes were favorable, with no major perioperative complications, such as neurovascular injuries or cerebrospinal fluid leakage. If SMT removal resulted in insufficient exposure of the trigeminal nerve, endoscopic assistance or alternative surgical approach, such as the anterior petrosal approach, was considered. The study emphasized the importance of recognizing this anatomical variation to predict operative difficulty and to perform safe and complete MVD with fewer potential complications.

  Hemophilia A, a deficiency of coagulation factor Ⅷ, is the most common congenital bleeding disorder. If the family history suggests hemophilia A, instrumental delivery should be avoided to prevent bleeding complications from birth injuries. However, instrumental delivery may be considered in cases with no family history of hemophilia A. Here, we present the case of a neonatal patient with hemophilia A who underwent instrumental delivery due to the lack of a family history. The patient developed severe intracranial hemorrhage that required a craniotomy for hematoma removal. Although activated partial thromboplastin time (APTT) prolongation is the key to diagnosing hemophilia, it should be noted that APTT can be physiologically prolonged in neonates. In addition, since administration of fresh frozen plasma (FFP) alone does not have sufficient hemostatic effects in hemophilia A, care must be taken during surgery.

  Anterior and posterior approaches are commonly used for surgical decompressive procedures of intervertebral foraminal stenosis presenting with cervical radiculopathy. However, extraforaminal stenosis is limited anteriorly by vertebral arteries and posteriorly by facet joint resections. Therefore, surgical access to extraforaminal stenosis in the middle cervical spine is the most difficult.

  We report the case of a 74-year-old man who underwent posterior cervical foraminotomy with fixation for painful C5 paralysis, but C5 paralysis remained. He had residual extraforaminal stenosis and added decompression fusion with a posterolateral approach. Postoperative symptoms completely recovered.

  Posterolateral decompression from the posterior cervical triangle may represent a third approach for cervical radiculopathy, particularly C5 palsy. Anatomical considerations of the neck muscles, facet joints, and C5 nerve root are also reported.