Published papers

Rupture of arteriovenous malformations (AVM) may be caused by venous outflow restriction, but there is no radiographic evidence of this. We report a case showing only a venous thrombus preceding intracranial haemorrhage from AVM. This is the first evidence that venous thrombus results in AVM rupture in its natural history.

To date, no clinical observations have been reported for histopathological changes in human gliomas under antiangiogenic treatment.We collected six glioblastomas resected under bevacizumab treatment. Histopathological investigation was performed by hematoxilyn-eosin staining and immunohistochemistry for CD34, VEGF, VEGFR1/2, HIF-1α, CA9, and nestin as compared to eleven control glioblastomas to assess the differences in histological features, microvessel density, expression of VEGF and its receptors, tumor oxygenation, and status of glioma stem-like cells.In the six tumors resected under bevacizumab, microvascular proliferation was absent, and microvessel density had significantly decreased compared with that of the controls. The expressions of VEGF and its receptors were downregulated in two cases of partial response. HIF-1α or CA9 expression was decreased in five of the six tumors, whereas the decreased expression of these markers was noted in only one of the 11 control glioblastomas. The expression of nestin significantly decreased in the six tumors compared with that of the controls, with the remaining nestin-positive cells being relatively concentrated around vessels.We provide the first clinicopathological evidence that antiangiogenic therapy induces the apparent normalization of vascular structure, decrease of microvessel density, and improvement of tumor oxygenation in glioblastomas. These in situ observations will help to optimize therapy.

Dural sinus malformation (DSM) is a rare paediatric vascular malformation characterised by abnormal dilation of the posterior dural sinus. Owing to its rarity, the pathophysiology of DSM has not been fully elucidated. We report a case of prenatally diagnosed DSM with an unusual clinical course. We detected DSM in a male foetus in the 26th week of gestation by using foetal ultrasonography. Although the DSM regressed during the foetal stage and the arteriovenous shunt was insignificant in the neonate, the shunt rapidly developed four months after birth. The neonate also had postnatal de novo brainstem cavernous malformation (CM), which also developed rapidly, supposedly due to the aggravated venous hypertension resulting from the DSM. We successfully treated the aggravated shunts by endovascular transarterial and transvenous embolisation six times over two years and, subsequently, the clinical condition and the size of the brainstem CM became stable. The DSM and CM seemed to have a metameric origin. Such aberrant cases could help to further the understanding of DSM.

Steroid psychosis is a frequent complication of steroid treatment. Although perioperative steroid replacement therapy is generally administered in patients undergoing pituitary surgery, there are no previous reports concerning the development of steroid psychosis after perioperative steroid replacement therapy following pituitary surgery. We herein report a case of steroid psychosis induced by perioperative steroid replacement therapy for pituitary surgery. A 35-year-old man presented with a visual disturbance that had persisted for 1 year. A magnetic resonance imaging scan showed a large pituitary tumor, and a laboratory study revealed slight dysfunction of the hypothalamo-pituitary-adrenal axis. The patient was diagnosed with a non-functioning pituitary tumor and underwent tumor resection via the endoscopic endonasal approach. The initial dose of perioperative steroid replacement therapy was 200 mg of hydrocortisone administered immediately before the operation. The replacement dose was gradually tapered and discontinued over a 7-day period. On postoperative day 4, the patient exhibited an elated mood, grandiose delusions, anxiety, and agitation. We diagnosed these psychiatric symptoms as steroid psychosis induced by steroid replacement and we prescribed risperidone as a treatment. The symptoms gradually improved and did not recur. This case highlights the risk of steroid psychosis following treatment with perioperative steroid replacement therapy for pituitary adenoma and raises questions regarding the appropriateness of perioperative steroid replacement for pituitary adenoma.

BACKGROUND: The anterior transpetrosal approach (ATPA) has been used in the resection of petroclival meningioma (PCM) for more than 20 years. Although PCM sometimes involves the petrosal vein and its preservation has been an important issue, the precise risk of petrosal vein sacrifice and subsequent venous complications associated with the use of the ATPA in patients with PCM has not yet been elucidated. METHODS: We used computed tomographic (CT) digital subtraction venography (DSV) in the retrospective analysis of the petrosal vein and its tributaries in patients with PCM before and after surgery. We also examined the incidence of postoperative venous complications in each of the patients. RESULTS: The detection rate of the petrosal vein and some of its tributaries on CT-DSV in patients with PCM was significantly lower than that in controls. Preoperatively, CT-DSV detected the petrosal vein in 71.8% of patients with PCM. The detected petrosal veins were preserved after the operation in 64.3% of these patients. No venous complications involving petrosal vein were observed in any of the patients. Anastomosis between the petrosal vein and the basal vein via the pontotrigeminal vein was found to be significantly more developed in the patients with PCM compared with the controls. CONCLUSIONS: Our study demonstrated that the ATPA could be performed safely on patients with PCM from the viewpoint of venous preservation. Preoperative CT-DSV is important for assessing the petrosal vein and its tributaries to facilitate a safer operation.

A considerable number of people harbor intracranial aneurysms (IA), which is a focal or segmental disease of the arterial wall. The pathophysiologic mechanisms of IAs formation, growth, and rupture are complex. The mechanism also differs with respect to the type of aneurysm. In broad aspects, aneurysms may be considered a disease of the vessel wall. In addition to the classic risk factors and the genetic/environmental conditions, altered structural and pathologic events along with the interaction of the surrounding environment and luminal flow dynamics contribute to the aneurysm’s development and growth. In this review, we have tried to simplify the complex interaction of a multitude of events in relation to vessel wall in the formation and growth of IAs.

In the embryo, the primary head sinus (PHS) is the first venous drainage channel in the craniocervical region. During embryonic development, this channel regresses and usually disappears completely; accordingly, a remnant of the PHS is an extremely rare condition and has been described in only a few previous studies. Here, we report a case of remnant of the PHS with a dural arteriovenous fistula (dAVF) in an adult. The remnant of the PHS had penetrated the petrous bone to run from the middle fossa to the jugular bulb and served as a drain for the middle fossa dAVF. We used digital subtraction angiography and reconstructed cone-beam computed tomography in 3D rotational angiography to obtain detailed anatomic information about the remnant PHS and additionally scrutinised and discussed its features.

BACKGROUND: The endoscopic transclival approach is a method for reaching the anterior side of the brainstem. In making this approach, bleeding from the basilar plexus is often observed when cutting the dura overlying the clivus. Controlling such bleeding is essential. CASE DESCRIPTION: We performed a transvenous embolization of the basilar plexus before making the transclival approach. After embolization, bleeding from the basilar plexus during the operation decreased considerably. CONCLUSIONS: To our knowledge, this is the first report of transvenous embolization of the basilar plexus. If the basilar plexus is well developed on preoperative computed tomographic venography or digital subtraction angiography, this procedure is useful for controlling bleeding during endoscopic transclival surgery.

Cerebrospinal fluid (CSF) leakage is a common complication associated with endoscopic endonasal skull-base surgery (EESBS). Postoperative mobilization-associated postural changes are considered to cause CSF leakage. However, no study has demonstrated a robust relationship between postural changes and CSF leakage. We used upright computed tomography (CT) to clarify the effects of postural changes on the reconstructed skull base (RSB) after EESBS. Thirty patients who underwent EESBS at our institution were prospectively included, and their upright and supine CTs were compared to measure morphological changes in the RSB. Patient clinical data were also collected from medical charts and surgical videos, and their relationships with morphological changes were assessed. In upright CTs, the RSB shifted intracranially by 0.94 (0.0-2.9) mm on average. This shift was larger in cases with lesions extending to the sphenoid sinus, dural defects, intraoperative pulsation of the RSB, and large bone windows. The direction of the change was opposite to intuitive movement driven by gravity because of reduced intracranial pressure in the sitting position. Thus, these shifts can be directly associated with postoperative CSF leakage caused by reconstruction material displacement. Skull-base reconstruction and postoperative postural management accounting for these morphological changes may be necessary for preventing CSF leakage.

CT performed in the supine position has been highly effective in diagnosing organic diseases such as cancer, arteriosclerosis, and infections, significantly contributing to increased life expectancy. In an ageing society, extending healthy life expectancy becomes more critical, requiring early diagnosis of functional disorders. We have led the industry-academia collaboration in developing an upright MDCT system. Although this system maintains the same physical specifications as conventional MDCT, it differs significantly in imaging configuration—allowing supine, upright, and sitting positions—and offers improved workflow while requiring only two-thirds of the installation space. Unlike conventional MDCT, it allows for the assessment of anatomical changes under gravity. It also enables the objective diagnosis and grading of functional diseases, in which findings were not apparent on conventional CT, and enable the study of the pathogenesis of functional diseases which worsen symptoms in the upright position. Furthermore, it allows for noninvasive evaluation of dynamic functions such as swallowing and voiding, which can only be assessed in standing or sitting positions.

Purpose: This study aimed to examine the venous anatomy of the horizontal fissure (HF) of the cerebellum by using contrast-enhanced magnetic resonance imaging (MRI) and computed tomography venography (CTV). We also studied the venous anatomy and cerebellar structures surrounding the HF relevant to the suboccipital trans-HF (SOTHF) approach in cadaver studies. Methods: We conducted an imaging analysis of 200 cerebellar hemispheres from 100 patients who underwent surgical treatment for intracranial supratentorial lesions between March 2021 and March 2023 at our institution. All patients underwent preoperative contrast-enhanced MRI and CTV. A cadaver study was conducted to assess the feasibility of the medial, intermediate, and lateral surgical corridors of the SOTHF approach while preserving the veins. We also present a clinical case. Results: Veins traversing the HF longitudinally, which act as a potential barrier when splitting the HF, were observed in 82% of the hemispheres, with an average of 1.28 per hemisphere. Distinctive veins running horizontally along the HF, observed in 24% of hemispheres, also act as potential barriers during wide HF opening. Cadaver studies demonstrated essential anatomical structures around the HF and that the medial, intermediate, and lateral corridors of the SOTHF approach could be achieved while preserving surrounding venous structures. Conclusion: The SOTHF approach is feasible for accessing deep cerebellar lesions, the medial aspect of cerebellopontine angle, and the upper fourth ventricle. Preoperative analysis and prediction of the venous architecture around the HF can enhance the safety and efficiency of the surgery.

Background: Vasa vasorum (VVs) is a Latin word representing vessels of vessels. VVs are usually found on the adventitia of the parent vessel and infrequently reach the media and intima, depending on the size and type of the parent vessels and physiological and pathological conditions. The VVs include arteries, capillaries, veins, and lymphatic vessels, involving the oxygenation and nourishment of the vessel’s wall to sustain its healthy state. Accumulated studies have revealed that VVs are involved in various intracranial lesions, including atherosclerotic diseases, aneurysms, and shunt diseases. The current review aims to review and integrate past and recent findings and knowledge on VVs and to facilitate our understanding of VVs and intracranial pathology involving VVs. Methods: A literature review was carried out with a focus on the role of VVs by searching the Pubmed database. Results: We identified 71 articles that discuss the role of VVs. We discussed the anatomical structure, physiological significance, and pathological significance of the VV. Conclusion: VV is not only involved in the nutrition and metabolism of the vascular wall but is also deeply involved in the pathogenesis of inflammation, ischemia, and thrombosis of the vascular wall. In addition, in the central nervous system, intracranial vascular wall nutrient particularities and VVs are closely related to the pathogenesis of cerebral aneurysms, subarachnoid hemorrhage, arteriovenous shunt disease, atherosclerotic lesions, and other conditions.