Scalp video-electroencephalography (video-EEG) monitoring should be analyzed thoroughly to preoperatively evaluate stereoelectroencephalography (SEEG). Formulating the working hypotheses for the epileptogenic zone (EZ) considering "anatomo-electroclinical correlations" is the most crucial step, which determines the placement of SEEG electrodes. If these hypotheses are insufficient, precise EZ identification may not be achieved during SEEG recording.

In ictal semiology analysis, temporal and spatial patterns with reference to ictal EEG changes are emphasized. In frontal lobe epilepsy, seizures often begin with relatively widespread synchronous activity, and complex motor symptoms manifest within seconds. Due to the wide area involved and intense interhemispheric connectivity, a comprehensive evaluation is often required. Hypotheses are formulated on the basis of the motor symptoms and emotional manifestations that are related to the prefrontal cortices. In temporal lobe epilepsy, EEG onset often precedes clinical onset. Propagation from the EZ to locations within and outside of the temporal lobe is examined from both the EEG and semiological standpoint. The characteristics of contralateral versive seizures, contralateral tonic seizures, and frequent focal onset bilateral tonic-clonic seizures indicate a higher risk of temporo-perisylvian epilepsy. In parietal/occipital lobe epilepsy, despite that some symptoms result from activity in the immediate vicinity, stronger connectivity with other regions usually contributes to the generation of prominent ictal semiology. Hence, multilobar electrode placement is often useful in practice. For insular epilepsy, it is important to understand the anatomy, function, and networks between other regions. A semiological approach is one of the most important clues for electrode implantation and interpretation of SEEG.

The detailed changes in disc properties after intradiscal injection of condoliase remain controversial. At 3 and 9 months after administration, radiographic changes in discs were investigated. A total of 41 patients (men, 25; median age, 46 years) who underwent regular follow-up magnetic resonance imaging at 3 and 9 months after administration without additional invasive therapy were retrospectively investigated. The intensity changes of the nucleus pulposus based on the Pfirrmann disc grading system, midsagittal disc height, and maximum protrusion length of herniation were assessed. In addition, disc height changes were compared between 24 patients aged <50 years (young group) and 17 patients aged ≥50 years (over 50s group). The overall mean disc heights were 9.1, 7.5, and 7.6 mm preoperatively, at 3 months, and at 9 months, respectively, with a significant reduction at 3 months (P < 0.001) and no significant changes thereafter. The mean maximum protrusion length of herniation significantly and gradually decreased. The overall proportions of Pfirrmann disc grades after administration were equivalent between 3 and 9 months. However, the recovery from Pfirrmann disc grades IV to III was confirmed in 8 of 17 cases (47.1%) between 3 and 9 months, whereas 6 of 20 cases (30.0%) showed a decline from III to IV. Patients in the young group with pretreatment disc height >11 mm had the greatest reduction in disc height than the over 50s group. In conclusion, the clinical outcomes in the over 50s group were comparable to those in the young group after injection of condoliase, whereas young patients with higher disc were more susceptible to disc height reduction.

Chemonucleolysis utilizing condoliase is a minimally invasive treatment for lumbar disc herniation (LDH) aimed at reducing intervertebral disc pressure and enhancing symptoms. In this study, lower limb pain was measured using the numeric rating scale (NRS) the day after treatment and 1 and 3 months after treatment. Prognostic factors were assessed, categorizing participants into an improvement group (I-group) for NRS lower limb pain scores of ≥3.5 and a non-improvement group (N-group) for scores of <3.5. This study included a total of 225 patients treated between April 2020 and March 2023. The mean age was 46.5 ± 16.5 years, with 151 males. The mean duration of illness was 6.2 ± 8.52 months. As of the day after treatment, 60 cases were classified into the I-group, 118 cases at 1 month after surgery, and 152 cases at 3 months after surgery. The disease duration before treatment was significantly shorter in the I-group at 1 (8.19 ± 8.74 [I-group] vs. 5.17 ± 8.04 [N-group] months) and 3 months (8.51 [I-group] ± 7.35 vs. 5.69 ± 8.87[N-group] months) after treatment. The comparison of baseline leg pain NRS shows a difference in leg pain NRS in the I-group when compared on the day after treatment (6.02 ± 2.64 [I-group] vs. 7.50 ± 1.79 [N-group]), 1 (5.13 ± 2.69 [I-group] vs. 7.58 ± 1.66 [N-group]), and 3 months (4.42 ± 2.70 [I-group] vs. 7.34 ± 1.77 [N-group]). Chemonucleolysis using condoliase for LDH can improve symptoms the day after treatment and can be a minimally invasive treatment to avoid surgery.

Several new studies have been conducted on cerebrospinal fluid (CSF) dynamics. Our educational guidelines, the Model Core Curriculum for Medical University, recommend access to the best current information. However, we do not know whether or when to introduce changes to this concept.

We surveyed which theory of CSF dynamics taught to students by neurosurgeons. The old theory is the bulk flow theory, and the new theory explains that CSF is produced from the choroid plexus and capillaries; CSF then pulsates and drains into the venous and lymphatic systems through newly discovered pathways.

Old and new theories were taught to 64.8% and 27.0% of students, respectively. The reason for teaching the old theory was to help them understand the pathogenesis of noncommunicating hydrocephalus (77.1%), whereas the reason for teaching the new theory was to teach the latest knowledge (40.0%). Physicians who wished to teach the new theory in the near future accounted for 47.3%, which was higher than those who would teach the new theory in 2022 (27.0%), and those who still wished to teach the old theory in the near future accounted for 43.2%.

An education policy on CSF dynamics will be established when we interpret ventricular enlargement and its improvement by third ventriculostomy in noncommunicating hydrocephalus based on the new theory. The distributed answers in the survey shared that it is difficult to teach about CSF dynamics and provided an opportunity to discuss these issues.

It has been reported that various clinical criteria indicate computed tomography (CT) examination for mild head injury (MHI). However, the decision to perform CT for MHI largely depends on the physician. Data on severe head injuries is available in sources such as the Japan Neurotrauma Data Bank, but only a few data has been collected on MHI. A total of 1688 patients with MHI (Glasgow Coma Scale 14 and 15) treated at our hospital from June 2017 to May 2019 were reviewed. CT was performed in 1237 patients (73.28%), and intracranial hemorrhage was detected in 50 patients. Three patients deteriorated, and all were surgically treated. Statistical analysis of the presence or absence of acute intracranial hemorrhage and "risk factors for complications of intracranial lesions in MHI" showed significant differences in unclear or ambiguous accident history (p = 0.022), continued post-traumatic amnesia (p < 0.01), trauma above the clavicles including clinical signs of skull fracture (skull base or depressed skull fracture) (p = 0.012), age <60 years (p < 0.01), coagulation disorders (p < 0.01), and alcohol or drug intoxication (p < 0.01). The 453 patients who did not satisfy these risk factors included only one patient with intracranial hemorrhage, so the negative predictive value was 99.78%. This study shows that the "risk factors for complications of intracranial lesions in MHI" are effective criteria for excluding acute intracranial hemorrhage and CT should be actively considered for patients with the above factors that showed significant differences.