Abnormal foreshortening of a Flow Re-Direction Endoluminal Device caused by in-stent thrombosis immediately after deployment.

Thromboembolic complications are a concern in the treatment of cerebral aneurysms using a flow diverter. In this study, we report a case of abnormal foreshortening of a Flow Re-Direction Endoluminal Device (FRED) caused by in-stent thrombosis immediately after its deployment. A 72-year-old woman had a large cavernous carotid aneurysm, which caused ptosis and diplopia. FRED deployment was planned, and dual antiplatelet therapy was initiated 2 weeks before the procedure. Under systemic heparinization, FRED was deployed with local compaction over the aneurysm orifice. Cone-beam computed tomography subsequently revealed slightly poor wall apposition at the proximal side. While the balloon catheter was prepared for angioplasty, the stent became abnormally foreshortened, the proximal side slipped into the aneurysm, and the internal carotid artery became occluded. FRED was removed using a snare wire, and recanalization was obtained. The lumen of the removed FRED was filled with thrombus. The antiplatelet therapy was changed to triple regimen, and a Pipeline Flex embolization device was placed 1 month later. At that time, no thromboembolic complications were noted. It was considered that thrombotic occlusion was followed by foreshortening of FRED on the distal side because of antegrade blood flow. Multiple factors, such as increased mesh density by locally compacted stent deployment, slightly poor wall apposition, clopidogrel resistance, and the dual-layer structure of FRED, may have been involved in thrombus formation.

Evaluation of the differences in pressure applied to the vessel wall by different types of balloon remodeling microcatheters in an experimental model.

BACKGROUND: We examined compliance differences among balloon remodeling microcatheters, which have not been established previously. METHODS: Straight and 120° angulated vascular models were created in a 3 mm diameter tube with 3 mm hole (vascular model A), a tube with a 4 mm hole (vascular model B), and a 4 mm diameter tube (vascular model C). We compared the pressure exerted when each balloon was herniated 1 or 2 mm between three compliant balloons (SHOURYU SR, TransForm C, and Scepter C) and four super-compliant balloons (HyperForm, SHOURYU HR, TransForm SC, and Scepter XC). RESULTS: In vascular model A, there was a significant difference in the pressure exerted by compliant balloons and super-compliant balloons in both the straight and angulated models. In the straight model (1 and 2 mm), the lowest pressure was exerted by HyperForm (super-compliant balloons group) and SHOURYU SR (compliant balloons group). The lowest pressure was exerted in the angulated model by HyperForm (super-compliant balloons group) and Scepter C (compliant balloons group). The Scepter balloon exerted higher pressure in the straight model than other balloon remodeling microcatheters but less in the angulated model. In vascular model B, the pressure decreased in all balloons compared with model A. In vascular model C, the pressure increased in all balloons compared with model A. CONCLUSIONS: Pressure differed across balloon remodeling microcatheters. In addition, vessel shape and diameter, and hole size, affected the results. Our findings can help select balloon remodeling microcatheters.

Streak Metal Artifact Reduction Technique in Cone Beam Computed Tomography Images after Endovascular Neurosurgery.

Cone beam computed tomography (CBCT) images are degraded by artifacts due to endovascular implants. We evaluated the use of streak metal artifact reduction technique (SMART) in non-contrast CBCT images after endovascular neurosurgery obtained from 148 patients (125 with aneurysm and 23 with dural arteriovenous fistula [dAVF]). Three neurosurgeons evaluated the cistern and brain surface visibility in CBCT images with and without SMART correction based on a 4-point scale (1, excellent; 2, good; 3, limited; and 4, insufficient). Significant improvement in visibility was achieved when the median scores improved from 4 or 3 to 2 or 1 or from 2 to 1. Metal artifact reduction in adjacent slices without metal and new artifacts after SMART correction was also examined. A significant improvement was achieved regarding the visibility of the cistern in 90 (60.8%) images and of the brain surface in 108 (73.0%) images. Metal size (cistern: odds ratio [OR], 0.91 per 1 mm increase; 95% confidence interval [CI], 0.83-0.99), irregular metal shape (cistern: OR, 0.18; 95% CI, 0.05-0.60 and brain surface: OR, 0.15; 95% CI, 0.05-0.45), and infratentorial lesions (cistern: OR, 0.37; 95% CI, 0.14-0.96 and brain surface: OR, 0.30; 95% CI, 0.11-0.80) were negatively correlated with improved visibility. Metal artifact reduction in adjacent slices without metal was obtained in 25.6% and 34.8% of images with aneurysm and dAVF, respectively. New artifacts after SMART correction were found in 4.8% and 13.0% of images with aneurysm and dAVF, respectively. SMART is especially effective for supratentorial small aneurysms.

Management of Asymptomatic Vertebral Artery Injury Caused by a Cervical Pedicle Screw Malposition: Two Case Reports.

Iatrogenic vertebral artery (VA) injury in cervical fusion is an extremely rare complication but can lead to serious sequelae. We present two successful cases of internal trapping for preventing delayed-onset ischemic stroke after iatrogenic VA stenosis caused by a cervical pedicle screw. A 34-year-old female underwent posterior cervical fusion for C4/C5 dislocation fracture. No neurological deficits were observed after the operation. However, the postoperative images revealed that the left C5 pedicle screw perforated the transverse foramen, and the left VA was suspected to be occluded at the screw insertion site. Before revision surgery, we tried to embolize the injured VA with coils. A microcatheter could be navigated from the ipsilateral VA to the distal of the screw, and internal trapping was performed with coils. Another case is that of a 50-year-old male with cervical spondylosis, who underwent posterior decompression and cervical fusion. The neurological symptoms did not deteriorate after the operation. However, the postoperative computed tomography images revealed the perforation of the right C3 transverse foramen by the pedicle screw. In right vertebral angiography, about 70% stenosis was observed at the screw insertion site. Although revision surgery was not planned due to good stability, we embolized the right VA after balloon occlusion test, to prevent the delayed-onset thromboembolic complications. Both the patients recovered without any neurological deficits. Iatrogenic VA injuries, even if asymptomatic immediately after surgery, can lead to serious sequelae in case of delayed-onset ischemic stroke. Therefore, careful attention should be paid when the screw perforates the transverse foramen.

Direct Vertebral Artery Puncture During Open Surgery for the Endovascular Treatment of a Recurrent Vertebro-Vertebral Arteriovenous Fistula.

BACKGROUND: Vertebro-vertebral arteriovenous fistula (VVAVF) is a condition in which there is an arteriovenous shunt directly connecting the extracranial vertebral artery to the vertebral venous plexus. Many reports have described fistula occlusion or vertebral artery trapping as treatments for VVAVF. Here, we describe a case in which endovascular treatment for recurrent VVAVF using a transfemoral approach was unsuccessful; thus, the vertebral artery (VA) was directly punctured during open surgery and the treatment was successful. CASE DESCRIPTION: The patient was a 47-year-old female who had undergone endovascular treatment for VVAVF. The patient developed subarachnoid hemorrhage. Digital subtraction angiography revealed a left VVAVF. The left VA was trapped with coils at the C2 and C3 levels and an arteriovenous shunt formed from the VA between the 2-coil mass to the vertebral venous plexus. In addition, reflux was observed in the spinal vein. Endovascular treatment was attempted with a transfemoral approach, but we could not reach the shunt. Five days post-treatment, the patient had a second subarachnoid hemorrhage and surgery was performed to occlude the radiculomedullary vein; however, residual reflux went into the spinal vein from another spinal level. Later, the VA was directly punctured and treated with N-butyl cyanoacrylate, and the shunt disappeared. CONCLUSIONS: Direct puncture of the vertebral artery was useful in this case, where it was difficult to reach the lesion. Although direct VA puncture is associated with more complications than the transfemoral or transbrachial approach, it may be an option when other methods are difficult.