Aichi Niwa

Activation of Ras/MEK/ERK signaling in chronic subdural hematoma outer membranes.

Chronic subdural hematoma (CSDH) is considered to be an angiogenic disease. Vascular endothelial growth factor (VEGF), one of the important growth factors regulating angiogenesis, is expressed in the neomembranes and also in hematoma fluid, and the Ras/MEK/ERK signaling pathway has been implicated in angiogenesis by VEGF. In the present study, the status of this signaling pathway in CSDH outer membranes was examined using outer membranes obtained during trepanation surgery. The expression levels of Ras, Ras-GAP, c-Raf, MEK, ERK, phosphorylated (p)-ERK, endothelial nitric oxide synthase (eNOS) and actin were examined by western blot analysis; the expression of p-ERK was also examined by immunohistochemistry. Ras, Ras-GAP, c-Raf, MEK, ERK and eNOS were detected in all cases. In addition, the expression of p-ERK was confirmed in all cases, and p-ERK was localized to the endothelial cells of the vessels in CSDH outer membranes. These findings indicated that Ras/MEK/ERK signaling is activated in the CSDH outer membranes and suggested the possibility that the Ras/MEK/ERK pathway might be activated by VEGF and play a critical role in the angiogenesis of CSDHs.

Upper cervical cord compression due to a C-1 posterior arch in a patient with ossification of the posterior longitudinal ligament and a kyphotic cervical spine in the protruded-head position: case report.

In this paper the authors report the case of a patient with ossification of the posterior longitudinal ligament (OPLL) below the axial vertebra (C-2) at the kyphotic cervical spine, with an atlas vertebra (C-1) posterior arch that compressed the spinal cord with the head in a pathognomonic position, similar to a protruded position. This condition appears to be very rare. The morphological findings between the kyphotic cervical spine and OPLL, the upper occipitocervical junction, and the protruded-head position are discussed. A 40-year-old man presented with severe pain radiating to both legs when he yawned, sneezed, or extended his jaw (a protruded-head position). A kyphotic cervical spine with OPLL below C-2 was observed using CT and radiography, yet sagittal T2-weighted MRI failed to identify abnormal findings in a neutral or extension position, except for a slight cervical canal stenosis. However, in a pathognomonic protruded-head position, sagittal T2-weighted MRI showed a C-1 posterior arch that severely compressed the spinal cord at the upper cervical level. Therefore, the authors believe that the severe pain radiating to both legs was caused by a spinal canal stenosis due to a C-1 posterior arch impingement. The C-1 posterior arch was resected, and after the surgery, the patient indicated that the intolerable pain had disappeared. In conclusion, in patients with OPLL and a kyphotic cervical spine, the authors propose that the pathognomonic protruded position is valuable for estimating disrupted compensatory mechanisms at the upper cervical junction.

Pathomorphological description of the shunted portion of a filum terminale arteriovenous fistula

BACKGROUND CONTEXT The clinical morphology of a filum terminale arteriovenous fistula (f-AVF) is well known; however, pathological details of the fistulized portion are unknown. Herein, we report the pathological findings of the f-AVF. STUDY DESIGN Case report and literature review. PURPOSE To present a detailed pathological examination of the fistulized portion of the f-AVF. METHODS A 71-year-old man presented with gradually worsening bilateral foot paresthesias and anal dysesthesia. T2-weighted magnetic resonance imaging showed flow voids surrounding an edematous conus medullaris and cauda equina with spinal stenosis at L3-L4 and L4-L5. Spinal digital subtraction angiography demonstrated an f-AVF fed by the left T9 intercostal artery. RESULTS We performed laminotomies of L3 and L4 to open the dura mater and found a hypertrophic filum terminale. It was resected, leaving a length of 2 cm between the abnormal proximal end and normal distal end. The f-AVF completely disappeared after the surgery. On pathological examination, the filum terminale included two vessels at the proximal end and one at the distal end. At the proximal end, immunostaining showed one vessel that was definitively an artery with both an internal elastic membrane (IEM) and smooth muscle. The other was a vein and lacked an IEM. On the distal side, the collagen fibers gradually increased, the IEM partially disappeared from the arterial wall, and the vein became arterialized with a thin IEM. At the distal end the two vessels joined. Therefore, we speculated that the fistulized portion of the f-AVF was not a fistula point but had some lengths where the artery had characteristics of a vein and there was venous arterialization. CONCLUSIONS The filum arteriovenous shunting occurred at the portion where there was venous arterialization and the artery had the characteristics of a vein. Therefore, resecting the filum terminale requires more proximal from the normal distal end.

Pitfalls in the Management of Atlanto-Occipital Dislocation

Atlanto-occipital dislocation (AOD) is rarely seen in clinic because it is characteristically immediately fatal. With recent progress in the pre-hospital care, an increasing number of AOD survivors have been reported. However, because the pathophysiology of AOD is not clearly understood yet, the appropriate strategy for the initial management remains still unclear. We report a case of successful AOD treatment and describe important points in the management of this condition. It is important to note that abducens nerve palsy is a warning sign of AOD and that AOD can result in a life-threatening distortion of the arteries and the brain stem. We recommend the application of a halo vest to protect the patients neural and vascular competence as the immediate initial step in the treatment of AOD. Horns grading system is useful in assessing indications for surgery. Finally, when performing posterior fixation, C2 should be included because of the anatomy of the ligamentous architecture.

Plasmapore-Coated Titanium Cervical Cages Induce More Rapid and Complete Bone Fusion After Anterior Cervical Discectomy and Fusion as Compared to Noncoated Titanium Cages

OBJECTIVE The aim of this study was to examine the solid bone fusion rates between Plasmapore-coated titanium cages (PPC group) and non-Plasmapore-coated titanium cages (N-PPC group) in patients who received anterior cervical decompression and fusion (ACDF). METHODS Of 78 patients who received ACDF at the hospital, a follow-up period greater than 2 years was possible for 61 patients, including 30 in the PPC group and 42 in the N-PPC group. Evaluations were performed at 3, 6, 12, and 24 months after surgery. Radiological stabilization (RS) was defined as the restriction of spinous process movement to <3 mm and the absence of a halo around the cages on flexion-extension radiographs. Solid bone fusion (SBF) was defined as the formation of bony bridges between the fixed vertebral bodies in sagittal computed tomography sections. The rates of RS and SBF were compared between both groups. RESULTS The differences in RS were not significant between the 2 groups during the follow-up period. However, the SBF rates at 6 and 12 months were significantly higher in the PPC group (26.7% and 56.7%) than in the N-PPC group (5% and 21.4%). Moreover, 63.3% (19 of 30) of patients in the PPC group demonstrated RS at 3 months, and of these patients, SBF was observed in 100% (19 patients) after 24 months, respectively. In comparison, the SBF rates in the N-PPC group were 86%. CONCLUSIONS Plasmapore-coated titanium cages enabled more rapid solid bone fusion. We suggest that these types of cages might help to reduce postoperative radiograms.

Novel Vertebral Artery Flow Reversal Method for Preventing Ischemic Complication during Endovascular Intervention

BACKGROUND AND PURPOSE We report a secure endovascular approach for the treatment of vascular lesions of the posterior circulation. Even if a large profile guide catheter is wedged in the unilateral vertebral artery (VA), our VA flow reversal method can prevent ischemic complications, including the spinal cord infarction. CASE PRESENTATION The patient was a 64-year-old woman who had been followed up for arteriovenous malformation (AVM) and an unruptured aneurysm of the basilar artery-superior cerebellar artery bifurcation. Endovascular treatment was performed because minor bleeding occurred from the AVM. When a 6-French guide catheter was navigated into the right VA, the guide catheter became completely wedged, and blood flow between the tip of the catheter and the VA union was fully stagnated. Because ischemia of the anterior spinal artery and right posterior inferior cerebellar artery could persist for a few hours during the endovascular procedure, we built a continuous reversal circulation from the guiding catheter tip to the femoral vein. The flow stagnation disappeared immediately. There was no complication during embolization of both the AVM and aneurysm. CONCLUSIONS The VA flow reversal method was secure in this case in which the tip of the guide catheter became wedged in the VA during the endovascular procedure.

Novel Technique for Rapid and Accurate Insertion of a Microguidewire Tail Into Low-Profile Devices During Endovascular Procedures: The Paper Rail Method

Purpose: To report a novel technique (“paper rail”) to facilitate inserting the tail of a microguidewire into the tip of a low-profile device during endovascular procedures. Technique: A sterilized nonwoven fabric tape with a smooth glossy paper backing is used. The tape has several linear folds ideal for a paper rail. Holding each piece of equipment about 5 cm from its respective tip, both the tail of the guidewire and the tip of the catheter are navigated at a 30° angle toward each other in the crease until the guidewire enters the catheter. The paper rail technique was compared with the conventional freehand method under varying luminosities found in an operating room. The paper rail technique was most effective in suboptimal lighting, where the mean time was reduced from 83 seconds with the conventional method to 20 seconds with the paper rail maneuver. The times required to insert the wire with the paper rail method were comparable (~22 seconds) at all light levels. Conclusion: The paper rail method may help improve the speed and accurate insertion of the tail of a microguidewire into the tip of low-profile devices during endovascular procedures. It may be particularly useful for physicians in a low-light environment or trainees.

Efficacy of the proximal balloon flow control method for endovascular coil embolisation as a novel adjunctive technique: A retrospective analysis:

Background and purpose In our previous study, we established the utility of 8-F balloon guide catheters for anterior circulation aneurysms. This study aims to assess the efficacy of the proximal flow control method using 8-F balloon guide catheters for coil deployment into the aneurysms as a novel adjunctive technique for aneurysmal coil embolisation along with local balloon neck remodeling, stent assist and double catheter techniques. Materials and methods We retrospectively analysed patients who underwent endovascular coiling of anterior circulation aneurysms between August 2013 and December 2017. Results Of 206 patients enrolled in this study, the balloon of the guiding catheter was inflated to assist coil deployment in 43 patients (20.9%). In addition, the proximal flow control method found utility in cases with small aneurysms and relatively narrow-necked internal carotid artery. We observed no intraprocedural complications in this study. Conclusion This technique enabled secure coil deployment without navigating another microcatheter or balloon catheter around the aneurysms.

Posterior inferior cerebellar artery with an extradural origin from the V3 segment: higher incidence on the nondominant vertebral artery

OBJECTIVE The posterior inferior cerebellar artery (PICA) and the vertebral artery (VA) often exhibit anatomical variations at the craniovertebral junction (CVJ). An example of this is the PICA originating extradurally from the V3 segment of the VA. To date, some cadaveric investigations have been reported, but the incidence and relationship of this variation to the VA and the atlas as observed on clinical imaging have not been discussed. This study evaluated the prevalence of PICAs originating from the V3 on CT scanning. Other variations of the atlas and VA were also analyzed. METHODS CT images from a series of 153 patients who underwent 3D CT angiography (CTA) were analyzed, and variations of the PICA, VA, and atlas were investigated. RESULTS A total of 142 patients (284 sides) were analyzed; 11 patients (7.2%) were excluded due to poor image quality. The most common VA variation was the PICA originating from V3 (9.5% of 284 sides), which was more frequently observed on the nondominant VA than the dominant VA (22.5% vs 6.25%, p = 0.0005). A VA with a PICA end was identified in 4 sides (1.4%), which is the same incidence as observed in the persistent first intersegmental VA (1.4%). VA fenestration was only found in 1 side (0.35%). Regarding the atlas, ponticulus posticus was observed in 24 sides (8.5%). There was no relationship between the incidence of ponticulus posticus and the variations of the VA. CONCLUSIONS A PICA originating from V3 was the most common VA variation at the CVJ and was more common on the nondominant VA. Three-dimensional CTA is useful for the evaluation of this variance. Surgeons should be mindful of this variation during operations.