Development of a Navigation-guided Fence-post Catheter for Brain Tumor Resection.

BACKGROUND: Navigation system devices have been developed to allow precise resection of brain tumor. The fence-post catheter techniques that use a navigation system have been used in many neurosurgery centers. However, an exclusive catheter for the fence-post catheter techniques have not been made, and substituted silicon tube of the cerebral ventricle drainage or a Nelaton catheter is widely used. OBJECTIVE: In this brief technical note, we describe a new fence-post catheter with steel tip device that was designed for more precise tissue resection and is useful in tumor resection. METHODS: The newly designed fence-post catheter helps to visually gauge the accurate depth from the tumor bottom during tumor resection. Furthermore, the catheter tip has moderate weight and is made of a non-magnetic material. RESULTS: Using our fence-post catheter, which has a metal part at the tip of the tube (length, 13 mm), operators can clearly notice that they are getting closer to base of the tumor by checking the metal part during the resection of deep tumors. CONCLUSION: Our newly developed fence-post tube enables easy confirmation of the distance to deep-tissue regions and improves the degree of safety during tumor removal. J. Med. Invest. 69 : 117-119, February, 2022.

Continued-Maintenance Therapy with High-dose Methotrexate Improves Overall Survival of Patients with Primary Central Nervous System Lymphoma.

BACKGROUND: PCNSL is mainly treated with HD-MTX-based chemotherapy with or without WBRT. However, As WBRT is associated with delayed neurotoxicity leading to dementia in the elderly, many institutes reported benefits of intensive chemotherapy or high-dose chemotherapy with ASCT. We investigated whether treatment with HD-MTX and rituximab, followed by continued-maintenance HD-MTX monotherapy (3.5g / m2), improves overall survival (OS). METHODS: In this retrospective, single-center trial 52 immunocompetent patients with newly diagnosed PCNSL were included. All were treated between January 2005 and December 2017. The controls were 18 patients who, between 2005 and 2011, had received 3 cycles of HD-MTX and then adjuvant treatment with WBRT. In 2011 we started HD-MTX continued-maintenance therapy to treat 34 PCNSL patients. In the induction phase, these patients received HD-MTX every 14 days until a complete response (CR) was observed. When CR was obtained, maintenance therapy with HD-MTX (3.5g / m2) was delivered every three months. RESULTS: In 3-year overall survival (OS) there was a statistically significant difference between the two groups [controls : 33.1% (95%, CI 12.4 - 55.7%) ; maintenance group : 74.9% (95%, CI 55.6 - 86.7%) (p < 0.02)]. Conclusion : The induction of HD-MTX based chemotherapy followed by continued-maintenance HD-MTX monotherapy improved OS compared with chemoradiotherapy consisting of HD-MTX followed by WBRT. J. Med. Invest. 68 : 286-291, August, 2021.

Gelatin-thrombin Hemostatic Matrix-related Cyst Formation after Cerebral Hematoma Evacuation: A Report of Two Cases.

The gelatin-thrombin matrix, Floseal, is an excellent novel hemostatic agent that is used in various surgical fields. Thrombin is a serine protease, and the conversion of prothrombin to thrombin is an essential step in the coagulation cascade. However, thrombin can induce blood-brain barrier (BBB) disruption and vasogenic brain edema. This report describes two cases of gelatin-thrombin matrix-related cyst formation after cerebral hematoma evacuation. An 82-year-old man with a gelatin-thrombin matrix-related cyst was treated by cyst drainage and fenestration to the lateral ventricle. Histological evaluation of the cyst wall showed a gelatin-thrombin matrix reserve, marked infiltration of inflammatory cells, and foam cell accumulation. In addition, an 85-year-old woman with a gelatin-thrombin matrix-related cyst was treated with steroids and responded well. In both cases, the post-treatment course was uneventful. Cyst shrinkage and no recurrence were observed. The gelatin-thrombin matrix can cause cyst formation with brain edema. This is the first report demonstrating the cyst wall pathology and the steroid responsivity on cyst shrinkage. The mechanism of cyst formation is thought to be thrombin-induced BBB disruption. Excess gelatin-thrombin matrix should be carefully removed from the surgical beds, particularly those having a blinded space from the neurosurgical microscope.

Temporal crescent syndrome caused by a lateral ventricular glioependymal cyst: case report.

Temporal crescent syndrome is a monocular visual field defect involving the temporal crescent of one eye caused by a retrochiasmal lesion. The most anterior portion of the striate cortex is the only area where the retrochiasmal lesion produces a monocular visual field defect. The authors present the case of a 9-year-old boy who presented with mild headache. MRI revealed a cyst with cerebrospinal fluid signal intensity, occupying the body and trigone of the right lateral ventricle. Conservative treatment with regular clinical and radiological follow-up was chosen because neurological examination findings were normal. Three years later, the patient experienced blurred vision with a temporal crescent defect in the left eye. Endoscopic cyst fenestration was performed, and the pathological findings indicated a glioependymal cyst. After surgery, the monocular temporal crescent disorder was resolved. MRI indicated shrinkage of the cyst and improvement in the narrowing of the anterior calcarine sulcus. These findings suggested that the temporal crescent syndrome was caused by a lateral ventricular glioependymal cyst. This is the first known report of temporal crescent syndrome caused by a lateral ventricular glioependymal cyst. In patients with monocular temporal crescent disorder without intraocular disease, a retrochiasmal lesion in the most anterior portion of the striate cortex should be considered.

Posttraumatic Cerebrospinal Fluid Leak Associated with an Upper Cervical Meningeal Diverticulum.

BACKGROUND: Spontaneous intracranial hypotension (SIH) has been increasingly recognized as a phenomenon caused by cerebrospinal fluid (CSF) leaks; however, its pathogenesis remains unclear. CASE DESCRIPTION: We report 2 cases of SIH resulting from CSF leak from a meningeal diverticulum at the C2 nerve root sleeve. The first case is that of a 46-year-old man who experienced orthostatic headache after a bicycle accident at age 45. Computed tomography (CT) myelography revealed CSF leaks at the C1-2 level. He underwent epidural blood patch therapy, but it was unsuccessful. Next, we performed direct surgery and found a meningeal diverticulum originating from the left C2 nerve root; therefore, we ligated the diverticulum. His symptoms and image findings strikingly improved after surgery. The second case is that of a 45-year-old man who experienced orthostatic headache 1 month after jumping into a river. Magnetic resonance imaging of the head showed bilateral subdural hematoma. CT myelography revealed CSF leaks at the C1-2 level and multiple cyst formations at the cervical and thoracic nerve root sleeves. epidural blood patch was performed, and his symptoms immediately improved. CONCLUSIONS: Recent studies have reported that meningeal diverticulum is involved in various cases of CSF leaks. The 2 cases indicate that traumatic accidents, such as back-and-forth neck movement or falls, presumably induce an increase in CSF pressure, followed by the rupture of an existing meningeal diverticulum, leading to CSF leak.