Over the last four decades, neurosurgical operating techniques have greatly improved with the advent of the operation microscope and the drastic evolution of medical engineering technologies. In the field of epilepsy treatment where, even though electrophysiological monitoring through scalp EEG and/or chronic subdural electrodes is still considered the gold standard, various types of newly developed non-invasive monitoring apparatus, techniques and surgical intervention are enabling us to better understand the epilepsy phenomenon through a more detailed etiology while achieving better prognoses as well. In this article, we review the current status of surgical intervention for epilepsy syndromes with special reference to the ongoing evolution of medical engineering technologies.

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  Clinical EEG provides us with diagnostic information of epileptogenicity by epileptiform discharges, i.e., spikes, sharp waves, which reflect the paroxysmal depolarization shifts (PDS) in the epileptic neurons. Currently advanced technology has enabled us to record wide-band EEG : direct current (DC) shifts and high frequency oscillation (HFO). The both conditions could widen the neurophysiological definition of epiletgenicity.
  Ictal DC shifts was recorded by using a DC amplifier in 1960 s with technical difficulty, but recently is by applying very small low frequency filter (0.016 Hz) of an AC amplifier which has the large input impedance more than 200 Mohm without difficulty in patients with invasive electrodes (Ikeda et al., 1996, 1999, 2008). It could reflect the massive, synchronized paroxysmal depolarization of the neurons in the epileptogenic area, and thus also represents associated depolarization of the glia. It could be regarded as the surrogate markers of the core epileptogenicity in human epilepsy regardless of the etiology.
  Once HFO was thought to highly reflect epileptogenicity in human epilepsy, we have investigated both ictal DC shifts and HFO simultaneously in patients with intractable partial epilepsy by means of subdural electrodes (Imamura et al., 2011 : Kanazawa et al., 2015). It could suggest more active role of glia in not only generating DC shifts but also presumably in ictogenesis. Glia may be also a target of the drug to suppress the seizures and a potential index of epileptogenic area from both electrophysiological and neuroimaging points of view. This concept is also applicable to interictal state of slow activity.

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  The cortico-striato-thalamo-cortical (CSTC) loop has been regarded as an important theoretical concept in research intended to identify ways to interrupt the causative mechanism of functional neurological disease. According to the CSTC loop concept, individual circuits associated with motor, mood and cognitive function exist in the cortex, basal ganglia and thalamus, and these circuits work with each other, keeping close and appropriate relationships. Diseases that seem to involve a dysfunction of the CSTC loop are Parkinson’s disease, dystonia, obsessive compulsive disorder and Tourette syndrome. The representative state of these diseases differs depending mainly on which circuit is impaired. The majority of targets for therapy using deep brain stimulation (DBS) were established in the CSTC loop, and because it is difficult to treat motor functions separately, an individual’s mood and cognitive function may be affected by DBS. It is known that subthalamic nucleus (STN) -DBS sometimes cause emotional changes in patients. These findings regarding the CSTC loop are understandable from observations of healthy persons, whose physical activity increases when their mood is good and whose intellectual work stagnates when their mood is depressive. The CSTC loop concept has not only become a theoretical background for the mechanism of DBS ; it has also become useful in clinical practice. It has been reported that physical exercise can contribute to the prevention of depression and dementia and to the inhibition of the progress of Parkinson’s disease. It has also been reported that positive thinking and a stable emotional state help improve the status of a movement disorder and that physical exercise improves the cognition for pain.

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  This manuscript is a review of the neurosurgical treatments available for intractable chronic pain including stimulation therapy. Stimulation therapy for chronic pain includes deep brain stimulation (DBS), electrical motor cortex stimulation (EMCS), repetitive transcranial magnetic stimulation (rTMS) and spinal cord stimulation (SCS). DBS is not popular as a treatment for chronic pain. EMCS was developed by Tsubokawa and its use has subsequently expanded all over the world. However, the procedure is invasive, and as a result the use of rTMS is overtaking EMCS today. SCS is a less invasive technique and is also quite popular. Failed back surgery is a good indication for SCS. Post-stroke pain is often very difficult to control by drugs alone, but 40% of post-stroke pain patients experience a 30% pain reduction with SCS. Therefore, when treating post-stroke pain, SCS is definitely worth a try. Lesioning the dorsal root entry zone (DREZotomy) powerfully reduces the shooting pain caused by root avulsion, but stimulation therapies usually fail in this regard.
  When treating younger patients with peripheral pain, the presence of continuous pain and less motor and sensory disturbances all seem to be good indications for stimulation therapy including EMCS, rTMS and SCS, whereas the shooting pain caused by root avulsion seems best served by DREZotomy.

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  Spasticity can occur with various central nervous system (CNS) disorders. Severe spasticity, hypertonus and involuntary movements, together with motor paralysis, can impair voluntary movement, leading to a decrease in activities of daily living (ADL). Intrathecal baclofen (ITB) therapy is now being used to treat such patients, and based on its efficacy and safety, ITB therapy now represents an important treatment for spasticity.
  ITB therapy has been used in more than 1000 patients since its introduction in Japan in 2006, and awareness of this treatment is increasing, although ITB therapy is still only used by a limited number of neurosurgeons. The clear inference is that many patients have yet to receive the benefits of this treatment.
  This paper, which includes our own experience, discusses the indications for ITB therapy, basic surgical technique, and treatment outcomes. We want to present the most up-to-date information about ITB therapy to neurosurgeons.

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  We present two cases with ruptured blood blister-like aneurysm of the internal carotid artery treated by overlapping stent with coil embolization in their acute stage. After the first stent was deployed over the aneurysm neck, a very soft coil was delivered into the aneurysm through a jailed microcatheter. Second stent was deployed inside the first one before coil detachment. This overlapping stenting method contributed to stabilization of the first coil in the small and fragile aneurysm. Tight packing of the aneurysm was not considered necessary in both cases. Follow-up angiogram showed complete occlusion of the aneurysm. Overlapping stent and coil embolization was an effective and safe technique to avoid re-rupture and keep parent artery flow, and can be an option for the treatment of ruptured blood blister-like aneurysm of the internal carotid artery.

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  We report a case of bilateral chronic subdural hematomas (CSDHs) that recurred three times in a patient with a history of gastric cancer and dysfibrinogenemia. We resorted to embolization of the middle meningeal arteries (MMA) to prevent recurrence. Angiograms showed abnormal shadows that suggested exudative bleeding from small branches of the MMA. While the right CSDH was treated with n-butyl cyanoacrylate (NBCA), the left CSDH was treated with coil embolization. The right side resolved without recurrence ; however, the left side had asymptomatic recurrence. The patient died of disseminated intravascular coagulation (DIC) due to gastric cancer without recurrence of the CSDHs after embolization.
  Embolization of the MMA, especially using NBCA, is an effective treatment for intractable CSDHs under DIC.

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  A 63-year-old man was admitted to our hospital with complaint of progression in his numbness of bilateral lower limbs, and with a gait disturbance. Neurological examinations on admission revealed monoparesis of the right lower limb. Conventional magnetic resonance imaging (MRI) demonstrated a syringomyelia at the Th4-5 level. Cine mode MRI showed membrane-like structures at the Th6 level, and the patient was diagnosed with a spinal arachnoid cyst complicated with syringomyelia. The patient underwent Th4-5 laminectomy and the arachnoid cyst was removed. Postoperative MRI demonstrated that the cyst had disappeared and the syringomyelia had spontaneously shrunk. After the operation, his neurological symptoms were improved remarkably. Therefore, surgical excision of the cyst is effectively decreases the syringomyelia associated with a spinal arachnoid cyst. This case suggests that cine mode MRI will be useful for preoperative diagnosis of the spinal arachnoid cyst.

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