[Microvascular Decompression for Trigeminal Neuralgia Due to Venous Compression].

In microvascular decompression surgery for trigeminal neuralgia, the veins are essential as an anatomical frame for the microsurgical approach and as an offending vessel to compress the trigeminal nerve. Thorough arachnoid dissection of the superior petrosal vein and its tributaries provides surgical corridors to the trigeminal nerve root and enables the mobilization of the bridging, brainstem, and deep cerebellar veins. It is necessary to protect the trigeminal nerve by coagulating and cutting the offending vein. We reviewed the clinical features of trigeminal neuralgia caused by venous decompression and its outcomes after microvascular decompression. Among patients with trigeminal neuralgia, 4%-14% have sole venous compression. Atypical or type 2 trigeminal neuralgia may occur in 60%-80% of cases of sole venous compression. Three-dimensional MR cisternography and CT venography can help in detecting the offending vein. The transverse pontine vein is the common offending vein. The surgical cure and recurrence rates of trigeminal neuralgia with venous compression are 64%-75% and 23%, respectively. Sole venous compression is a unique form of trigeminal neuralgia. Its clinical characteristics differ from those of trigeminal neuralgia caused by arterial compression. Surgical procedures to resolve venous compression include nuances in safely handling venous structures.

Exoscopic microvascular decompression for hemifacial spasm and trigeminal neuralgia.

The 4K 3D exoscope system is becoming increasingly used in neurosurgery. Its 3D ultra-high-definition image is valuable in identifying and dissecting the delicate neural and vascular structures during microvascular decompression. In this video, the authors describe several nuances and details to perform the exoscopic microvascular decompression, including the exoscope layout and the modified supine position. Several illustrative case presentations highlight the benefits of exoscopic surgery. The authors' exoscopic microvascular decompression series of 159 patients showed noninferior surgical outcomes compared to the operative microscope with no significant increase in surgical risk. In conclusion, an exoscope can be a practical alternative to performing microvascular decompression. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23122.

JNK2-MMP-9 axis facilitates the progression of intracranial aneurysms.

Intracranial aneurysm (IA) can cause subarachnoid hemorrhage or some other hemorrhagic stroke after rupture. Because of the poor outcome in spite of the intensive medical care after the onset of hemorrhage, the development of a novel therapeutic strategy like medical therapy to prevent the progression of the disease becomes a social need. As the reduction of arterial stiffness due to the degeneration of the extracellular matrix via Matrix Metalloproteinases (MMPs) becomes one of the central machineries leading to the progression of IAs through a series of studies, factors regulating the expression or the activity of MMPs could be a therapeutic target. In the present study, specimens from human IA lesions and the animal model of IAs were used to examine the expression of c-Jun N-terminal kinase (JNK) which might exacerbate expressions of MMPs in the lesions to weaken arterial walls resulting in the progression of the disease. In some human IA lesions examined, the expression of p-JNK, the activated form of JNK, could be detected mostly in the medial smooth muscle cells. In IA lesions induced in rats, the activation of JNK was induced during the progression of the disease and accompanied with the activation of downstream transcriptional factor c-Jun and importantly with the expression of MMP-2 or -9. The genetic deletion of Jnk2, not Jnk1, in mice significantly prevented the incidence of IAs with the suppression of the expression of MMP-2 or MMP-9. These results combined together have suggested the crucial role of JNK in the progression of IAs through regulating the expression of MMPs. The results from the present study provides the novel insights about the pathogenesis of IA progression and also about the therapeutic target.

A synovial cyst-induced vertebral artery dissection in bow hunter's stroke: illustrative case.

BACKGROUND: Bow hunter's stroke (BHS) is a rare condition characterized by occlusion of the vertebral artery (VA) due to a head rotation. BHS typically results from neck hyperrotation, often due to anatomical factors. The authors present a case of BHS in a young male patient exacerbated by os odontoideum (OD), resulting in atlantoaxial dislocation, which ultimately led to VA dissection. OBSERVATIONS: A man in his 20s presented with persistent dizziness and nausea and initially received a diagnosis of a brain infarction. However, imaging revealed VA dissection caused by an OD with an associated synovial cyst. Surgical intervention, specifically atlantoaxial posterior fixation, resolved the instability and allowed for natural regression of the synovial cysts, preventing further vascular events. In this case, the OD with atlantoaxial dislocation was identified as the causative factor for BHS. The coexistence of a synovial cyst was a unique finding, likely triggered by chronic irritation caused by the OD. LESSONS: This case emphasizes the importance of thorough cervical spinal evaluation in young patients presenting with posterior circulation stroke. https://thejns.org/doi/10.3171/CASE2487.

Learning Curve Effect of Combined Technique Thrombectomy as First-Line Attempt for Acute Ischemic Stroke: A Single-Center Retrospective Study.

OBJECTIVES: We retrospectively examined the initial experience and learning curve after the introduction of thrombectomy with the combined technique using an aspiration catheter and a stent retriever as first-line attempt for acute ischemic stroke. METHODS: Consecutive patients undergoing thrombectomy for acute ischemic stroke at our institution between January 2020 and December 2022 were divided into 3 groups according to the year of thrombectomy. Patient characteristics and procedural, safety, and clinical outcomes were compared between the three year periods to determine predictors of favorable clinical outcome. RESULTS: In 2020, 2021, and 2022, the numbers of patients were 74, 70, and 90, respectively, with similar patient characteristics across the three years; successful recanalization rates were 79.7%, 97.1%, and 93.3%, respectively (P < 0.01 for the first 2 years); median procedure times were 67, 43, and 32 minutes, respectively (P < 0.01 for the first 2 years and P = 0.018 for the last 2 years); first pass effect rates were 20.3%, 41.4%, and 44.4%, respectively (P < 0.01 for the first 2 years); symptomatic intracranial hemorrhage rates were 14.9%, 2.9%, and 1.1%, respectively (P = 0.018 for the first 2 years); and percentages of modified Rankin Scale score 0-2 at 90 days were 24.3%, 42.9%, and 41.1%, respectively (P = 0.022 for the first 2 years). Procedure time (P = 0.038) and successful recanalization (P = 0.041) were independent predictors of favorable clinical outcome. CONCLUSIONS: The learning curve effect of the combined technique may be associated with better clinical outcome due to increased successful recanalization rates, shortened procedure time, and reduced symptomatic intracranial hemorrhage.