Republished:Aspiration catheter failure leading to carotid-cavernous fistula during stroke thrombectomy.

Endovascular thrombectomy in acute ischaemic stroke commonly uses aspiration catheters, either alone or in combination with stent retrievers. The Penumbra Aspiration System (Penumbra, Alameda, California, USA) was first approved by the US Food and Drug Administration in 2007, with low reported device-related complications. We present a case of a previously unreported complication related to malfunction of a Penumbra aspiration catheter during stroke thrombectomy resulting in a carotid-cavernous fistula.

Ticagrelor resistance: a case series and algorithm for management of non-responders.

The placement of cervical and intracranial stents requires the administration of antiplatelet drugs to prevent thromboembolic complications. Ticagrelor has emerged as the most widely used alternative in clopidogrel non-responders owing to its potent antiplatelet effects. Because ticagrelor does not require hepatic activation, many neurointerventionalists choose to forgo laboratory testing of platelet inhibition. In rare instances, patients may not achieve adequate platelet inhibition following ticagrelor administration. In this paper we review the mechanism of action of ticagrelor and its use in cerebrovascular procedures. We present two cases of ticagrelor non-responsiveness from two high-volume cerebrovascular centers, discuss their management, and propose an algorithm for managing ticagrelor non-responsiveness.

A Rare Case of Life-Threatening Multicompartmental Spontaneous Intracranial Hemorrhage From a Grade 1 Convexity Meningioma.

Meningiomas are slowly growing benign tumors. The incidence of hemorrhage associated with intracranial meningiomas is in the 0.5%-2.4% range. However, intracranial meningiomas with hemorrhagic presentation are associated with higher rates of overall major morbidity (36%) and mortality (21.1%). We report a case of a convexity meningioma presenting with intraparenchymal hematoma and bilateral acute subdural hematomas (SDH) in a comatose patient (Glasgow Coma Scale (GCS) score: 7) who had a history of recurrent episodes of headaches over the past few months. Hemorrhagic presentation of a meningioma is a rare but potentially devastating event. Early recognition of the potential underlying meningioma as a cause of bleeding followed by rapid appropriate additional imaging is crucial to direct treatment plans to achieve the best outcome.

The Positive Impact of Donor Bone Marrow Cells Transplantation into Immunoprivileged Compartments on the Survival of Vascularized Skin Allografts.

Using the vascularized skin allograft (VSA) model, we compared the tolerogenic effects of different allogeneic bone marrow transplantation (BMT) delivery routes into immunoprivileged compartments under a 7-day protocol immunosuppressive therapy. Twenty-eight fully MHC mismatched VSA transplants were performed between ACI (RT1a) donors and Lewis (RT11) recipients in four groups of seven animals each, under a 7-day protocol of alfa/beta TCRmAb/CsA (alpha/beta-TCR monoclonal antibodies/Cyclosporine A therapy). Donor bone marrow cells (BMC) (100 × 106 cells) were injected into three different immunoprivileged compartments: Group 1: Control, without cellular supportive therapy, Group 2: Intracapsular BMT, Group 3: Intragonadal BMT, Group 4: Intrathecal BMT. In Group 2, BMC were transplanted under the kidney capsule. In Group 3, BMC were transplanted into the right testis between tunica albuginea and seminiferous tubules, and in Group 4, cells were injected intrathecally. The assessment included: skin evaluation for signs and grade of rejection and immunohistochemistry for donor cells engraftment into host lymphoid compartments. Donor-specific chimerism for MHC class I (RT1a) antigens and the presence of CD4+/CD25+ T cells were assessed in the peripheral blood of recipients. The most extended allograft survival, 50-78 days, was observed in Group 4 after intrathecal BMT. The T cells CD4+/CD25+ in the peripheral blood were higher after intrathecal BMC injection than other experimental groups at each post-transplant time point. Transplantation of BMC into immunoprivileged compartments delayed rejection of fully mismatched VSA and induction of robust, donor-specific chimerism.

Falx Cerebelli Meningioma: Case Report of a Rarely Occurring Tumor, Management Nuances, and Literature Review.

The falx cerebelli is a small crescent fold of dura mater that is attached to the internal occipital crest and projects forward into the posterior cerebellar notch between the cerebellar hemispheres. We report a rare case of a 61-year-old female who presented with a 1-month history of headache and gait instability. Imaging findings were suggestive of a meningioma arising from the falx cerebelli. Complete surgical resection was achieved with a standard posterior fossa midline approach. Duraplasty was performed using animal allograft dura (Duraguard) and additional layers of oxidized cellulose preparation (Surgicel), fibrin sealant, and nonsuturable collagen matrix (Duragen) were utilized to reduce the risk of a cerebrospinal fluid leak. Pathology confirmed a World Health Organization (WHO) grade-I meningioma. Postoperatively, patient with asymptomatic thrombosis of the left transverse/sigmoid sinuses and later with a pseudomeningocele managed with a lumbar drain. To our knowledge, this is the second documented case in the literature. We discuss intraoperative nuances and unique aspects in the postoperative care and management of these patients.

Pipeline Embolization Device for treatment of high cervical and skull base carotid artery dissections: clinical case series.

BACKGROUND: Most cervical dissections are treated with anticoagulation or antiplatelet agents with very good results; however, some patients may benefit from endovascular intervention. High cervical and skull base dissections are often more challenging to treat because of the distal location and tortuous anatomy. The Pipeline Embolization Device (PED) may be a reasonable treatment option for this indication. OBJECTIVES: To report a case series of patients treated with the PED for high cervical and skull base dissections, focusing on their presentation, indications for treatment, dissection revascularization success, and pseudoaneurysm obliteration evaluated by imaging, and to review available pertinent literature. METHODS: We retrospectively reviewed all cases of high cervical and skull base dissections treated with a PED at our institution. Patient clinical characteristics, presentation, procedural and follow-up imaging, and clinical course were analyzed to evaluate for procedure complications, dissection revascularization success, pseudoaneurysm obliteration, and clinical outcome. RESULTS: This is a retrospective case series including 11 patients with 13 carotid dissections treated in our center. There were nine traumatic and four spontaneous dissections. The most common presentation was cerebrovascular accident/transient ischemic attack (CVA/TIA; 5 patients) and headache/face pain (4 patients). Eleven dissections were associated with pseudoaneurysms. Three patients failed medical management with anticoagulation, although flow-limiting stenosis was the main indication for endovascular intervention. Up to three PEDs per vessel were deployed. Angioplasty was used in 10 cases. Complete revascularization (<10% residual stenosis) was achieved in 91% of vessels and 50% of pseudoaneurysms were completely or near completely obliterated immediately after PED(s) deployment. Proximal iatrogenic dissection was the only intraoperative complication. Follow-up imaging was available for nine treated vessels and demonstrated patent PEDs without significant in-stent stenosis up to 9 months after intervention. 75% of pseudoaneurysms were completely obliterated at follow-up. One PED partially collapsed but had no neurological consequences. There were no new CVA/TIAs. CONCLUSIONS: Our initial experience with treatment of high cervical and skull base dissections with the PED appears to show that this technique may be a safe and viable treatment option. However, long-term results are needed to fully evaluate the efficacy of such treatment.

Peripheral nerve defect repair with epineural tubes supported with bone marrow stromal cells: a preliminary report.

INTRODUCTION: This study was performed to assess the effects of nerve gap repair with isogenic epineural tubes filled with isogenic bone marrow stromal cells (BMSC) as an alternative to autograft repair. METHODS: A total of 24 epineural tubes were transplanted as a conduit to bridge 20 mm nerve gap defects in 2 experimental groups. In group 1, the tube was filled with saline, whereas in group 2 with isogenic BMSC prestained with PKH-dye. In all, 12 autograft sciatic nerve repairs served as a control. Sensory and motor recovery was evaluated by gastrocnemius muscle index; pinprick, toe-spread tests; and somatosensory-evoked potentials at 6 and 12 weeks postrepair. Histomorphometry and immunostaining were also performed. RESULTS: Evidence of successful nerve regeneration was present in all animals at 6 and 12 weeks. There were no significant differences between experimental groups in functional recovery--toe-spread and pinprick tests; however, epineural conduit groups trended toward better toe-spread scores compared with autograft repair at 6 weeks. All animals had full sensory recovery as evaluated by pinprick at 12 weeks. Saline group had significantly higher gastrocnemius muscle index compared with other groups at 6 weeks; however, no differences were noted at 12 weeks. Histomorphometrical assessment did not reveal superiority of any group at 6 weeks postrepair. However, at 12 weeks, the BMSC group had significantly increased myelin thickness compared with other groups and larger diameter nerve fibers than autograft. In group 2, PKH-positive cells and expression of nerve growth factor, Laminin B2, glial fibrillary acidic protein, and vascular endothelial growth factor were confirmed. nerve growth factor- and glial fibrillary acidic protein-positive BMSC were also found inside the tube. CONCLUSION: The epineural tube is a viable, naturally occurring biologic conduit for nerve repair. Cotransplantation of BMSC-enhanced nerve regeneration by means of increased myelinization and expression of neurotrophic factors. Overall, obtained results with epineural tube/BMSC construct were comparable to autograft repair.

Isogenic venous graft supported with bone marrow stromal cells as a natural conduit for bridging a 20 mm nerve gap.

In this study, we introduce a technique for bridging large neural gaps, using an isogenic vein graft supported with isogenic bone marrow stromal cells (BMSC). In three groups a nerve defect of 20 mm was bridged with a vein graft. Our first experimental group comprized an empty venous graft, in group II the venous nerve graft was filled with saline where as in group III the venous nerve graft was filled with BMSC. The animals were tested for functional recovery up to 3 months post repair. Our results show that the BMSC filled venous graft resulted in significantly better regeneration of the nerve defect compared to controls, as confirmed by the functional recovery measured by somatosensory evoked potentials, toe spread, pin prick, and gastrocnemius muscle index. Conclusively, the results confirm that the vein graft supported with BMSC is associated with better functional nerve regeneration.

The effects of inflammation on glial fibrillary acidic protein expression in satellite cells of the dorsal root ganglion.

STUDY DESIGN: After undergoing L5 hemilaminectomy, chromic gut suture was placed onto the DRG and the animals were sacrificed at various time-points. OBJECTIVE: The purpose of this study was to identify the effects of inflammation on satellite cells (SCs) of the dorsal root ganglion (DRG) by analyzing glial fibrillary acidic protein (GFAP) expression in of the DRG at various time points. SUMMARY OF BACKGROUND DATA: SCs are neuroglial cells that closely interact with nerve cells of the DRG. The role of SC remains unknown GFAP expression increases in response to CNS injury. Loss of GFAP has impaired Schwann cell proliferation and delayed nerve regeneration after injury. METHODS: Sixty rats underwent a left L5 hemilaminectomy. In Group I, a chromic-gut suture was place topically on the DRG (n = 30), Group II was the sham surgery group (n = 30). DRGs were harvested at 6, 24, 48, 72 hours, and 7 days after surgery. In Group III, 6 control rats were killed and their bilateral L5 DRG harvested. The harvested DRG were analyzed using light microscopy for SC immunoreactivity, using GFAP, HIS-36, TNF-alpha, IL-1alpha, IL-1beta, IL-6 monoclonal antibodies. RESULTS: One hundred thirty-two DRGs were harvested for analysis. Naïve controls and neurons did not express GFAP. The SC sheath expressed GFAP as early as 6 hours postchromic gut application. In Group I, GFAP expression steadily increased after chromic-gut application with 100% of SC soma and SC sheaths being GFAP positive at 7 days. The contralateral DRG demonstrated delayed GFAP expression, with 83% of SC soma and SC sheaths were GFAP positive at 7 days. In Group II, 89% of sacs expressed GFAP by 7 compared to 79% in the contralateral undisturbed DRG. CONCLUSION: Under physiologic conditions, the expression of GFAP by SCs is undetectable. As the inflammatory process develops, GFAP expression steadily increases with 100% of SCs being GFAP immunoreactive 7 days after chromic gut application. These data suggest that SCs are the primary source of GFAP in the DRG. We hypothesize that SC play an important role in the response to early inflammatory injury.

Evaluation of epidural scar formation in lumbar spine after TachoComb application - an experimental study.

BACKGROUND AND PURPOSE: Scar formation after spine surgery in the lumbosacral region may be the cause of failed back surgery syndrome. Therefore efforts are made to find materials preventing excessive scar formation at the site of surgery. The aim of the study was to evaluate the usefulness of TachoComb application in prevention of epidural scar formation in a rat experimental model. This paper additionally presents a review of literature concerning other methods of local suppression of scar formation after posterior approaches to the lumbar spine. MATERIAL AND METHODS: The experimental study was carried out on 14 male Wistar rats. Rats were divided into 2 groups. Laminectomy was performed in the first group (control group: n=5). In the second group of animals (n=9) laminectomy was followed by TachoComb application on the exposed dura. Neurological condition of the studied animals was evaluated based on clinical observation, neurological tests and recording of somatosensory evoked potentials. Post mortem histological examination was the main method of assessment of the experimental material. RESULTS: Presence of scar in the vertebral canal, its extent and severity differed between experimental groups. Electrophysiological results were also different between studied groups. CONCLUSIONS: TachoComb prevents epidural scar formation after lumbar spine surgery. Its positive effect concerning neural transmission at the level of the medulla was proven by electrophysiological tests in which the amplitude of components I and II of SSEP in the TachoComb group were significantly higher than in the control group.