Safety Evaluation of Primary Carotid Stenting: Transcranial Doppler and MRI.

BACKGROUND AND PURPOSE: Cerebral emboli are generated by every step of standard carotid angioplasty and stenting. Primary carotid stenting (PCS) is a technique in which the use of balloon angioplasty (BA) is minimized to decrease the embolic load. The primary aim of this study is to establish the number of emboli generated by each step of primary stenting and determine the relationship to new diffusion (DWI) lesions on subsequent magnetic resonance imaging (MRI). METHODS: Eighty-five patients with severe, symptomatic carotid stenosis were prospectively recruited and underwent carotid stenting. Intraoperative transcranial Doppler was performed in 77 patients. The number and size of microemboli for each of seven procedural steps were recorded. Correlation was made with the number and location of new DWI lesions. RESULTS: PCS was performed in 73 patients. BA was required in 12 patients. The mean number of microemboli was 114, and most microemboli were generated by stent deployment, followed by BA. Balloon techniques generated significantly more emboli than primary stenting (p = 0.017). There was a significant relationship between total microemboli and new DWI lesions (p = 0.009), and between new DWI lesions in multiple territories and the severity of pretreatment stenosis (p = 0.002). CONCLUSIONS: During PCS, more emboli are generated by stent deployment than during any other stage of the procedure. When BA is necessary, more malignant emboli are generated but total emboli are unchanged and there is no difference in new diffusion lesions on MRI. PCS is safe and is not inferior to historical controls for the generation of new DWI lesions.

Interventional Neuroradiology: A Review.

Interventional neuroradiology (INR) has evolved from a hybrid mixture of daring radiologists and iconoclastic neurosurgeons into a multidisciplinary specialty, which has become indispensable for cerebrovascular and neurological centers worldwide. This manuscript traces the origins of INR and describes its evolution to the present day. The focus will be on cerebrovascular disorders including aneurysms, stroke, brain arteriovenous malformations, dural arteriovenous fistulae, and atherosclerotic disease, both intra- and extracranial. Also discussed are cerebral vasospasm, venolymphatic malformations of the head and neck, tumor embolization, idiopathic intracranial hypertension, inferior petrosal venous sinus sampling for Cushing's disease, and spinal interventions. Pediatric INR has not been included and deserves a separate, dedicated review.

Embolized cerebral arteriovenous malformations: a multivariate analysis of 101 excised specimens.

OBJECTIVE: Endovascular approaches have evolved from a technique practiced at very few centers to a widely available option in the management of arteriovenous malformations (AVMs) of the central nervous system. Embolization can be employed as definitive therapy or as an adjunct to surgical excision. A wide variety of embolic agents have been successfully developed and used in the clinical setting. In addition to facilitating vascular occlusion, embolic agents induce a number of reactive and destructive changes in vessel walls and the surrounding tissue. However, studies examining the pathological changes induced by different embolic agents and varying times of exposure are scarce. The goal of the present study was to compare embolic agents and time of exposure on the pathology in excised specimens. METHODS: The records of the Department of Pathology at the London Health Sciences Centre were searched for embolized AVMs for the 35-year period 1980-2015. All cases were reevaluated for clinical and technical variables and standardized histopathological findings. Cases were grouped by embolic agent, volume of agent used, and time to excision. RESULTS: A total of 101 specimens were identified. Embolic agents were invariably associated with a range of pathological findings, some of which may affect the integrity of vessel walls or the reestablishment of flow, thrombosis, acute and chronic inflammatory changes, angionecrosis, extravasation, and recanalization. The type of embolic agent did not predict differences in the incidence or severity of histopathological changes. Larger volumes of embolic agent were associated with a greater proportion of vessels containing embolic material. AVMs excised early (< 1 week postembolization) contained more acute vasculitis, while those excised later (≥ 1 week postembolization) were more likely to exhibit recanalization and foreign body giant cell infiltrates. CONCLUSIONS: Embolic agents induce a predictable range and temporal progression of pathological changes in cerebral AVMs. The embolic agents studied are indistinguishable in terms of the range and frequency of pathological reactions induced. Greater volumes of embolic agent are associated with more abundant agent within the lesion, but the proportion of vessels and vascular cross-sectional areas containing agent is small. Several changes are significantly associated with time postembolization. Acute vasculitis is a more common finding in the 1st week, while recanalization and foreign body-type granulomatous inflammation are more common at 1 week and beyond.

A systematic characterization of the factors influencing polymerization and dynamic behavior of n-butyl cyanoacrylate.

INTRODUCTION: Brain arteriovenous malformations are abnormal connections between arteries and veins without an intervening capillary bed. Endovascular glue embolization with N-butyl cyanoacrylate (NBCA) is an accepted form of treatment. The reported complication rates vary widely from 2% to 15%, and timing of polymerization appears to play a major role. Additionally, the interaction between NBCA and vessel surface as well as the presence of biological catalysts are poorly understood. METHODS: Polymerization time was measured for mixtures of Lipiodol/NBCA of 50/50, 70/30, and 60/40. The influence of pH, temperature, and the presence of biological catalysts on polymerization time was investigated. Contact angles were measured on polyvinyl alcohol cryogel (PVA-C), silicone, and endothelial surfaces in a submerged aqueous environment to assess physical surface interactions. High speed video analysis of glue injection through a microcatheter was performed to characterize simulated coaxial flow. RESULTS: NBCA polymerization rate increased with pH and temperature. A hydrophilic surface such as PVA-C was better than silicone at mimicking the physical properties of endothelium. Live endothelium provided a catalytic surface that at least doubled the rate of polymerization. Blood products further increased the polymerization rate in the following order (slowest to fastest): plasma, platelets, red blood cells (RBCs), and lysed RBCs. These factors could explain the discrepancy between in vitro and in vivo results reported in the current literature. High speed video analysis of NBCA injection showed dripping to jetting transition with significant wall effect which deviated from previous ideal assumptions. CONCLUSIONS: The determinants of NBCA polymerization rate are multifactorial and dependent mainly on the presence of biological catalysts coupled with flow related wall interaction.

Retrospective review of percutaneous synovial cyst ruptures: increased thickness of the T2 hypointense rim on post-rupture MRI may be associated with need for subsequent surgery.

OBJECTIVE: To analyze MRI characteristics of lumbar facet synovial cysts and distinguish those requiring subsequent surgical management for recurrence, after percutaneous synovial cyst rupture. METHODS AND MATERIALS: Retrospective chart review conducted in patients undergoing percutaneous synovial cyst rupture between February 2012 and April 2015. Pre- and post-percutaneous rupture procedure MRI spine studies were serially reviewed. Synovial cyst sizes, T1 and T2 signal characteristics and changes therein, T2 hypointense (or 'dark rim') thickness and change, and changes in the complexity of cyst signals were compared. Operative notes for patients who underwent subsequent surgical removal of recurrent synovial cysts were reviewed. RESULTS: 24 patients received 41 percutaneous synovial cyst rupture procedures, with a technical success rate of 82.9%. There was a significant difference in the mean increased thickness of the T2 hypointense rim on the first post-rupture MRI scan (p=0.0411) between patients requiring subsequent surgery and those who did not. There was a significant difference in the average sizes of synovial cysts before the procedure (p=0.0483) in those requiring subsequent surgery and those who did not. Five complications were noted (12.2%), mostly involving leg pain or weakness. Of the nine patients who underwent subsequent surgery post-synovial cyst rupture, six of the surgeries had recorded difficulty pertaining to scarring and/or adherence of the cyst to dura. CONCLUSIONS: A larger increase in thickness of the T2 hypointense rim on the first post-rupture MRI scan and a larger synovial cyst size were associated with the need for subsequent surgical resection.

Outcomes of General Anesthesia and Conscious Sedation in Endovascular Treatment for Stroke.

Background Recent studies have strongly indicated the benefits of endovascular therapy for acute ischemic stroke, but what remains a continued debate is the role for general anaesthesia versus conscious sedation (CS) for such procedures. Retrospective studies have found poorer neurological outcomes in patients who underwent general anesthesia (GA); however, some have revealed worse baseline stroke severity in these patients. Methods This study is a retrospective cohort study aimed at comparing mortality and morbidity of GA versus CS in patients treated with endovascular intervention in acute ischemic stroke. Chi-square and t-test analyses were used. Results Patients in the GA (n=42) group were more likely to be deceased than those in the CS (n=67) group at hospital discharge, 3 months, and 6 months poststroke onset. Morbidity, as defined by modified Rankin Score, was significantly greater in the GA group at hospital discharge, and a similar trend was seen in morbidity at 3 months postdischarge. Conclusion General anesthesia for endovascular intervention in acute ischemic stroke was associated with increased mortality and poorer neurological incomes compared with conscious sedation. In our study, age, gender, history of hypertension, history of diabetes, and baseline National Institute of Health Stroke Scale were not significantly different between the groups. Although the need for a randomized, prospective study on this topic is clear, our study represents further corroboration of the safety and efficacy of conscious sedation in these procedures.

A novel approach to symptomatic lumbar facet joint synovial cyst injection and rupture using iGuide navigational software: A case report and review.

Spinal synovial cysts are benign protrusions of facet joint capsules caused by degenerative spondylosis, most frequently involving the L4-5 level, and commonly lead to symptoms of back pain, radiculopathy and neurogenic claudication. Although percutaneous treatment via facet joint steroid injection with cyst rupture can provide significant symptom relief, cyst rupture is not always achievable via an indirect trans-facet approach due to limited access from severe degenerative changes. In this case, we describe a successful approach to direct cyst access using a laser-guided navigational software in a patient with severe facet joint osteophytosis. We provide a brief review of literature.

Catheter based selective hypothermia reduces stroke volume during focal cerebral ischemia in swine.

BACKGROUND: Total body hypothermia is an established neuroprotectant in global cerebral ischemia. The role of hypothermia in acute ischemic stroke remains uncertain. Selective application of hypothermia to a region of focal ischemia may provide similar protection with more rapid cooling and elimination of systemic side effects. We studied the effect of selective endovascular cooling in a focal stroke model in adult domestic swine. METHODS: After craniotomy under general anesthesia, a proximal middle cerebral artery branch was occluded for 3 h, followed by 3 h of reperfusion. In half of the animals, selective hypothermia was induced during reperfusion using a dual lumen balloon occlusion catheter placed in the ipsilateral common carotid artery. Following reperfusion, the animals were sacrificed. Brain MRI and histology were evaluated by experts who were blinded to the intervention. RESULTS: 25 animals were available for analysis. Using selective hypothermia, hemicranial temperature was successfully cooled to a mean of 26.5 °C. Average time from start of perfusion to attainment of moderate hypothermia (<30 °C) was 25 min. Mean MRI stroke volumes were significantly reduced by selective cooling (0.050±0.059 control, 0.005±0.011 hypothermia (ratio stroke:hemisphere volume) (p=0.046). Stroke pathology volumes were reduced by 42% compared with controls (p=0.256). CONCLUSIONS: Selective moderate hypothermia was rapidly induced using endovascular techniques in a clinically realistic swine stroke model. A significant reduction in stroke volume on MRI was observed. Endovascular selective hypothermia can provide neuroprotection within time frames relevant to acute ischemic stroke treatment.

Failure of aneurysm occlusion by flow diverter: a role for surgical bypass and parent artery occlusion.

Flow diverters represent a paradigm shift in the treatment of aneurysms. However, unusual and poorly understood complications are being reported. We present a case of a giant internal carotid artery terminus aneurysm treated with flow diversion that progressively and symptomatically enlarged despite a reduction in the filling portion. Complete occlusion of the aneurysm and reduction in mass effect occurred through superficial temporal artery- middle cerebral artery bypass and parent artery occlusion. Incomplete aneurysm occlusion following flow diversion has been reported, but mechanisms and predisposing factors are speculative and definitive solutions have not been described. This case illustrates a potential solution.

Visual outcomes for surgical treatment of large and giant carotid ophthalmic segment aneurysms: a case series utilizing retrograde suction decompression (the "Dallas technique").

OBJECT: The authors report their results in a series of large or giant carotid ophthalmic segment aneurysms clipped using retrograde suction decompression. METHODS: A retrospective review of clinical data and treatment summaries was performed for 18 patients with large or giant carotid artery ophthalmic segment aneurysms managed operatively via retrograde suction decompression. Visual outcomes, Glasgow Outcome Scale (GOS) scores, and operative complications were determined. Postoperative angiography was assessed. RESULTS: During a 17-year period, 18 patients underwent surgery performed using retrograde suction decompression. The mean aneurysm size was 26 mm. Three patients presented with subarachnoid hemorrhage. Fourteen of 18 patients presented with visual symptoms. Eleven (79%) of these 14 patients experienced visual improvement and the remaining 3 (21%) experienced worsened vision after surgery. Of 3 patients without visual symptoms and a complete visual examination before and after surgery, 1 had visual worsening postoperatively. One aneurysm required trapping and bypass, and all others could be clipped. Postoperative angiography demonstrated complete occlusion in 9 of 17 clipped aneurysms and neck remnants in the other 8 clipped aneurysms. One (5.5%) of 18 patients experienced a stroke. Eighteen patients had a GOS score of 5 (good outcome), and 1 patient had a GOS score of 4 (moderately disabled). There were no deaths. There was no morbidity related to the second incision or decompression procedure. Prolonged improvement did occur, and even in some cases of visual worsening in 1 eye, the overall vision did improve enough to allow driving. CONCLUSIONS: Retrograde suction decompression greatly facilitates surgical clipping for large and giant aneurysms of the ophthalmic segment. Visual preservation and improvement occur in the majority of these cases and is an important outcome measure. Developing endovascular technology must show equivalence or superiority to surgery for this specific outcome.

Transcortical venous approach for direct embolization of a cavernous sinus dural arteriovenous fistula: technical case report.

BACKGROUND AND IMPORTANCE: Dural arteriovenous fistulas (dAVFs) represent 10% to 15% of all intracranial arteriovenous malformations. Most often, embolization is accomplished with transfemoral catheter techniques. We present a case in which embolization of a cavernous sinus dAVF was made possible through transcranial cannulation of a cortical draining vein. CLINICAL PRESENTATION: An 82-year-old woman presented with diplopia, left sixth cranial nerve palsy, intraocular hypertension, and bilateral chemosis. Angiography revealed a complex cavernous dAVF with cortical venous reflux, supplied by both external carotid arteries and the left meningohypophyseal trunk. Percutaneous transvenous access failed, and only partial occlusion was achieved by transarterial embolization. A frontotemporal craniotomy was performed to access the superficial middle cerebral vein in the left sylvian fissure. Under fluoroscopic guidance, a microcatheter was advanced through this vein to the floor of the middle cranial fossa and into the dAVF, permitting coil occlusion. CONCLUSION: This transcranial vein technique may be a useful adjunct in dAVF therapy when percutaneous transarterial or transvenous approaches fail or are not possible.

Cervical spine motion: a fluoroscopic comparison of the AirTraq Laryngoscope versus the Macintosh laryngoscope.

BACKGROUND: The optimal technique to intubate the trachea in patients presenting with a potential or documented cervical spine (C-spine) injury remains unresolved. Using continuous fluoroscopic video assessment, C-spine motion during laryngoscopy with an AirTraq Laryngoscope (King Medical Systems, Newark, DE) was compared to that with intubation using a Macintosh blade. METHODS: Twenty-four healthy surgical patients gave written consent to participate in a crossover randomized controlled trial; all patients were subjected to both Macintosh and AirTraq laryngoscopy with manual inline stabilization after induction of anesthesia. The C-spine motion was examined at four areas: the occiput-C1 junction, C1-C2 junction, C2-C5 motion segment, and C5-thoracic motion segment. The time required for laryngoscopy was also measured. RESULTS: C-spine motion using the AirTraq was less than that during Macintosh laryngoscopy, averaging 66% less (P < 0.01) at three of the motion segments studied, occiput-C1, C2-C5, and C5-thoracic. There was no difference at the C1-C2 segment. There was no significant difference in the time to accomplish laryngoscopy between the two devices. CONCLUSIONS: For patients in whom C-spine movement is undesirable, use of the AirTraq Laryngoscope may be useful to limit movement without an increase in the duration of intubation.