The evaluation of venous drainage patterns prior to surgery for skull base meningioma is important owing to their deep location and the vulnerability of surrounding vascular structures. In recent years, the microsurgical skull base approach has matured as a surgical technique, making it an important option for reducing complications related to skull base meningioma surgery. In addition, knowledge of the venous anatomy can prevent venous drainage route disturbance and potentially life-threatening complications. Hence, this topic review aimed to provide an overview of normal venous anatomy as it relates to the microsurgical skull base approach, discuss known changes in venous drainage routes that are associated with the progression of skull base meningioma and the selection of an appropriate operative approach with the highest likelihood of preserving venous drainage structures.

Simulation and planning of surgery using a virtual reality model is becoming common with advances in computer technology. In this study, we conducted a literature search to find trends in virtual simulation of surgery for brain tumors. A MEDLINE search for “neurosurgery AND (simulation OR virtual reality)” retrieved a total of 1,298 articles published in the past 10 years. After eliminating studies designed solely for education and training purposes, 28 articles about the clinical application remained. The finding that the vast majority of the articles were about education and training rather than clinical applications suggests that several issues need be addressed for clinical application of surgical simulation. In addition, 10 of the 28 articles were from Japanese groups. In general, the 28 articles demonstrated clinical benefits of virtual surgical simulation. Simulation was particularly useful in better understanding complicated spatial relations of anatomical landmarks and in examining surgical approaches. In some studies, Virtual reality models were used on either surgical navigation system or augmented reality technology, which projects virtual reality images onto the operating field. Reported problems were difficulties in standardized, objective evaluation of surgical simulation systems; inability to respond to tissue deformation caused by surgical maneuvers; absence of the system functionality to reflect features of tissue (e.g., hardness and adhesion); and many problems with image processing. The amount of description about image processing tended to be insufficient, indicating that the level of evidence, risk of bias, precision, and reproducibility need to be addressed for further advances and ultimately for full clinical application.

The Japanese population features the highest rate of elderly individuals worldwide. Moreover, Japan has the highest number of computed tomography/magnetic resonance imaging devices in the world, which has led to an increase in the incidental detection of meningioma in healthy elderly patients. Many previous papers have discussed the risks and indications for surgery in this patient population, but available information remains insufficient, and the definition of “elderly” has not been standardized. This review tried to clarify the published evidence and challenges associated with elderly meningioma based on a search of the PubMed database using the terms “meningioma,” “elderly,” and “surgery” for English-language clinical studies and collected related papers published from 2000 to 2016. Twenty-four papers were reviewed and classified by definition of elderly age: over 60, 65, 70, and 80 years old. Six of seven papers that defined the elderly cutoff as over 65 years old were published after 2010, which suggested the consensus definition. Four preoperative grading scoring systems were described and associated with mortality. The 1-year and 5-year mortality rates ranged from 0% to 16.7% and from 7% to 27%, which were comparable with unselected cohorts. Review of risk factor analysis emphasized the importance of considering the preoperative status, presence of comorbidities, and optimum surgical timing during patient selection. Careful choice of patients can also lead to better quality of life. A prospective randomized study considering patient frailty should address the causes and prevention of complications.

The authors describe the surgical anatomy for the endoscopic endonasal approach (EEA) to the ventrolateral skull base. The ventrolateral skull base can be divided into two segments: the upper lateral and lower lateral skull base. The upper lateral skull base includes the cavernous sinus and the orbit, while the lower lateral skull base includes the petrous apex, Meckel’s cave, parapharyngeal space, infratemporal fossa, etc. To gain access to the upper lateral skull base, a simple opening of the ethmoid sinus provides sufficient exposure of this area. To reach the lower lateral skull base, a transpterygoid approach, following ethmoidectomy, is a key procedure providing wide exposure of this area. Understanding of surgical anatomy is mandatory for treating ventrolateral skull base lesions via EEA. An appropriate, less-invasive approach should be applied depending on the size, location, and type of lesion.

Patients with malignant brain tumors are possibly at increased risk for surgical site infections (SSIs) considering the various medical situations associated with the disease. However, the actual rate of SSI after malignant brain tumor resection has not been well established, despite the potential impact of SSI on patient outcome. To investigate the incidence of SSI following malignant brain tumor surgery, we performed a retrospective study in 3 neurosurgical units. Subsequently, aiming at the reduction of incidence of SSI, we performed a prospective study using a care bundle technique in the same units. The SSI incidence in the retrospective (n = 161) and prospective studies (n = 68) were 4.3% and 4.4%, respectively, similar to the previously reports on general craniotomies. A care bundle does not appear to enhance prevention of SSI. However, future, large studies with a new care bundle should be planned based on a zero tolerance policy.

Given the anatomical proximity of tuberculum sellae meningioma (TSM) to the hypothalamo-pituitary system, pituitary function impairments are of great concern. We retrospectively investigated pituitary function changes following surgery in patients with TSM using pituitary provocation tests (PPTs). Thirty-one patients (27 females and 4 males) with TSM underwent initial transcranial surgery (29 patients) or transsphenoidal surgery (two patients); surgeries were performed carefully to avoid injuring the pituitary stalk. In 24 patients, the PPTs were performed via a triple bolus injection with regular insulin, thyrotropin-releasing hormone (TRH), and luteinizing hormone releasing hormone (LH-RH). Seven patients underwent a quadruple test (growth-hormone-releasing factor, corticotrophin-releasing hormone, TRH, and LH-RH). The preoperative and postoperative target hormone levels of the anterior pituitary were normal in 93.5% and 96.8% of patients, respectively. At least one hormonal axis demonstrated impaired PPT responses in two patients (6.5%) preoperatively and in one patient (3.2%) postoperatively. The growth hormone (GH) response was also well preserved. A compromised GH peak level was only observed in one patient (3.2%) preoperatively. Postoperatively, transient diabetes insipidus and transient hyponatremia were observed in four (12.9%) and eight (25.8%) patients, respectively. No patients needed permanent postoperative hormone replacement. The preoperative pituitary function was well preserved in most patients, including those with large tumors pushing against the pituitary stalk considerably or embedded in it. After careful surgery to avoid damaging the pituitary stalk, pituitary function was preserved. However, transient postoperative hyponatremia occurred in 25.8% of patients; thus, surgeons should pay careful attention to this issue.

We report two cases of cerebral venous thrombosis (CVT) which serial arterial spin labeling (ASL) was useful in evaluating the clinical course of the disease. A 48-year-old female presented with acute seizure, and was diagnosed as transverse-sigmoid sinus thrombosis. ASL imaging revealed low signal intensity in the right temporal lobe, suggesting the decreased perfusion by elevated venous pressure. Soon after the treatment, while the development of venous collateral has not fully observed by magnetic resonance (MR) angiography, low ASL signal within the right temporal lobe have shown remarkable improvement. A 65-year-old female presented with vomiting and subsequent seizure was diagnosed as superior sagittal sinus thrombosis. The low ASL signal within the right frontal lobe seen in the acute stage improved to the normal level by the course of time, before the good collateral can be seen by MR angiography. This is the first report to assess the sequential change of the cerebral perfusion of CVT by ASL, and ASL may provide additional useful information in combination with conventional modalities.