Stereoelectroencephalography (SEEG) is a method for invasive study of patients with refractory epilepsy. Localization of the epileptogenic zone in SEEG relied on the hypothesis of anatomo-electro-clinical analysis limited by X-ray, analog electroencephalography (EEG), and seizure semiology in the 1950s. Modern neuroimaging studies and digital video-EEG have developed the hypothesis aiming at more precise localization of the epileptic network. Certain clinical scenarios favor SEEG over subdural EEG (SDEEG). SEEG can cover extensive areas of bilateral hemispheres with highly accurate sampling from sulcal areas and deep brain structures. A hybrid technique of SEEG and subdural strip electrode placement has been reported to overcome the SEEG limitations of poor functional mapping. Technological advances including acquisition of three-dimensional angiography and magnetic resonance image (MRI) in frameless conditions, advanced multimodal planning, and robot-assisted implantation have contributed to the accuracy and safety of electrode implantation in a simplified fashion. A recent meta-analysis of the safety of SEEG concluded the low value of the pooled prevalence for all complications. The complications of SEEG were significantly less than those of SDEEG. The removal of electrodes for SEEG was much simpler than for SDEEG and allowed sufficient time for data analysis, discussion, and consensus for both patients and physicians before the proceeding treatment. Furthermore, SEEG is applicable as a therapeutic alternative for deep-seated lesions, e.g., nodular heterotopia, in nonoperative epilepsies using SEEG-guided radiofrequency thermocoagulation. We review the SEEG method with technological advances for planning and implantation of electrodes. We highlight the indication and efficacy, advantages and disadvantages of SEEG compared with SDEEG.

The discovery that ultrasound waves could be focused inside the skull and heated to high temperatures at a focal point goes back to 1944. However, because the skull causes the ultrasound waves to attenuate and scatter, it was believed that application of this technology would be difficult, and that it would be impossible to use this approach in the surgical treatment of intracranial diseases. Eventually, magnetic resonance image guided focused ultrasound (MRgFUS) surgery began being used to treat uterine fibroids, breast cancer and bone metastasis and locally confined prostate cancer. In the first ten years of the 21st century, new developments in this technology have been achieved, broadening the scope of practical application, and treatment is now being performed in various countries around the world. In 2011, third-generation transcranial focused ultrasound made it possible to use thermocoagulation and create intracranial lesions measuring 2 to 6 mm in diameter with a precision of around 1 mm. It was also possible to produce MR images which relay information of temperature changes in real time, enabling a shift from reversible test heating to irreversible therapeutic heating. This gave rise to the possibility of a minimally-invasive treatment with outcomes similar to those of conventional brain surgery. This method is paving the way to a new future not only in functional neurosurgery, but in cranial neurosurgery targeting conditions such as epilepsy and brain tumors, among others. In this paper, we describe the current state and future outlook of magnetic resonance image guided focused ultrasound, which uses computed tomography (CT) bone images in combination with MRI monitoring of brain temperature.

Several targets and targeting methods are utilized in stereotactic surgery to achieve tremor suppression for patients with intractable tremor. Recent developments in magnetic resonance imaging, including diffusion tensor imaging, have enabled the setting of appropriate targets in stereotactic surgery. In this retrospective study, the optimal target to suppress tremors in stereotactic surgery was explored using diffusion tensor image-based fiber tractography. Four tracts were focused on in this study, namely: the cerebello-thalamo-premotor cortical fiber tract, cerebello-thalamo-primary motor cortical fiber tract, spino-thalamo-somatosensory cortical fiber tract, and pyramidal tract. In 10 patients with essential tremor, we evaluated the thalamotomy lesions and active contacts of the lead in thalamic stimulation by diffusion tensor image-based fiber tractography to reveal which part of the cerebral cortex is most affected by stereotactic surgery. Tremor suppression and adverse events were also evaluated in the patients involved in this study. Consequently, the good tremor suppression was achieved in all patients. There had been no permanent adverse events 3 months after surgery. Twelve lesions in thalamotomy patients or active contacts of the lead in thalamic stimulation patients were on the cerebello-thalamo-premotor cortical fiber tract (12/14 lesions or active contacts: 86%). In conclusion, the cerebello-thalamo-premotor cortical fiber tract may be an optimal target for tremor suppression. Diffusion tensor image-based fiber tractography may enable us to both determine the optimal target to achieve strong tremor suppression and to reduce the number of adverse events by keeping lesions or electrodes away from important fiber tracts, such as the pyramidal tract and spinothalamic fibers.

As the world population becomes progressively older, the overall incidence of chronic subdural hematoma (CSDH) is increasing. Peak age of onset for CSDH has also increased, and recently the 80-year-old level has a peak. Many patients with CSDH have had prior treatment with anticoagulants and antiplatelet drugs, which have an accompanying risk of CSDH. In elderly patients with CSDH, symptoms of cognitive change (memory disturbance, urinary incontinence, and decreased activity) and disturbance of consciousness at admission were more frequent compared to younger patients with CSDH. The literature actually offers conflicting advice regarding CSDH treatment; however, burr hole surgery with drainage under local anesthesia is the most common surgical procedure, even in elderly patients. The recurrence rate of CSDH has not decreased over recent decades, and it has ranged from 0.36–33.3%. Outcomes in patients over 75 years old was significantly worse than for those younger than 75. Moreover, long-term outcomes for elderly patients with CSDH are poor. CSDH in the elderly is no longer a benign disease. In the future, it will be important for us to understand the mechanisms of onset and recurrence of CSDH and to develop more effective medical treatments and noninvasive surgical techniques for elderly patients.

Traumatic cerebrovascular injury (TCVI) is an uncommon clinical entity in traumatic brain injury (TBI), yet it may cause devastating brain injury with high morbidity and mortality. Early recognition and prioritized strategic treatment are of paramount importance. A total of 1966 TBI patients admitted between 1999 and 2015 in our tertiary critical care center were reviewed. Screening of TCVI was based on the Guidelines for the Management of Severe Head Injury in Japan. TCVI was confirmed in 33 (1.7%) patients; 29 blunt and 4 penetrating injuries. The primary location of the injury included 16 cervical, 6 craniofacial, and 11 intracranial lesions. On arrival, 15 patients presented with hemorrhage, 5 of these arrived in shock status with massive hemorrhage. Ten presented with ischemic symptoms. Sixteen patients underwent surgical or endovascular intervention, 13 of whom required immediate treatment upon arrival. Surgical procedures included clipping or trapping for traumatic aneurysms, superficial temporal artery - middle cerebral artery bypass, carotid endarterectomy, and direct suture of the injured vessels. Endovascular intervention was undertaken in 7 patients; embolization with Gelfoam (Pharmacia and Upjohn Company, Kalamazoo, MI, USA) or coil for 6 hemorrhagic lesions and stent placement for 1 lesion causing ischemia. Patients’ outcome assessed by the Glasgow Outcome Scale at 3 months were good recovery in 8, moderate disability in 3, severe disability in 9, persistent vegetative state in 1, and death in 12, respectively. In order to rescue potentially salvageable TCVI patients, neurosurgeons in charge should be aware of TCVI and master basic skills of cerebrovascular surgical and endovascular procedures to utilize in an emergency setting.

In recent years, instances of neurotrauma in the elderly have been increasing. This article addresses the clinical characteristics, management strategy, and outcome in elderly patients with traumatic brain injury (TBI). Falls to the ground either from standing or from heights are the most common causes of TBI in the elderly, since both motor and physiological functions are degraded in the elderly. Subdural, contusional and intracerebral hematomas are more common in the elderly than the young as the acute traumatic intracranial lesion. High frequency of those lesions has been proposed to be associated with increased volume of the subdural space resulting from the atrophy of the brain in the elderly. The delayed aggravation of intracranial hematomas has been also explained by such anatomical and physiological changes present in the elderly. Delayed hyperemia/hyperperfusion may also be a characteristic of the elderly TBI, although its mechanisms are not fully understood. In addition, widely used pre-injury anticoagulant and antiplatelet therapies may be associated with delayed aggravation, making the management difficult for elderly TBI. It is an urgent issue to establish preventions and treatments for elderly TBI, since its outcome has been remained poor for more than 40 years.

Following the modern raising of public awareness, the numbers of malpractice litigation are increasing in the health care delivery system in Japan despite the extensive efforts of physicians. Authors reviewed the issues of litigation and the reasons for court decision from the healthcare-related negligence lawsuits in the past 15 years in Japan and investigated the cautionary points for reducing potential litigation. Healthcare-related negligence lawsuits between January 2001 and December 2015 were retrieved and sorted in each clinical field from the database in Courts in Japan and investigated on the proportional factors of the claims and court decisions in the neurosurgical field. During the period, 446 of healthcare-related court decisions including 41 against neurosurgeons (9.2%) were retrieved. Three of 41 decisions retrieved were decisions to retries for lower court decisions. In 38 claims against the neurosurgeons, 26 identified the negligence and 12 dismissed. In 26 decisions in favor of the plaintiffs, identified negligence in diagnosis in 4, clinical judgment in 3, technical skills in 5, clinical management in 7 and process of informed consent in 7. Five out of 18 decisions after 2006 were identified as negligence in an informed consent process, and additional one, who was mainly identified in inadequate technical skills also identified existing an inadequate informed consent process as a fundamental cause of litigation. Neurosurgeons are a higher risk group for malpractice litigation in Japan and adequate informed consent is important to reduce the risk of litigation.