Maxillary artery pseudoaneurysm causing retinal artery occlusion.

Purpose: To report a novel case of central retinal artery occlusion in a 44-year-old male caused by emboli from a non-traumatic maxillary artery pseudoaneurysm. Observations: A 44-year-old male with history of hypertension presented to clinic with painless vision loss in his left eye. He was found to have a central retinal artery occlusion. Ocular massage and intraocular pressure lowering agents were administered and the patient was transferred to the emergency department for cerebrovascular work-up. Remarkably, the patient had rapid symptom improvement from no light perception to 20/70 after ocular massage and IOP agents. Neuroimaging studies discovered a maxillary artery pseudoaneurysm with anastomotic branches to the internal carotid artery via the foramen rotundum and Vidian artery. Endovascular embolization was performed to prevent further thromboembolic event. Conclusion and Importance: We believe this to be the first reported case of retinal artery occlusion caused by a maxillary artery pseudoaneurysm. This case demonstrates that visual deficits can be the presenting symptom of a non-traumatic maxillary artery pseudoaneurysm.

Early chemoprophylaxis for deep venous thrombosis does not increase the risk of hematoma expansion in patients presenting with spontaneous intracerebral hemorrhage.

BACKGROUND: Spontaneous intracerebral hemorrhage (ICH) is a significant cause of morbidity and mortality worldwide. The development of venous thromboembolism (VTE), including deep venous thrombosis or pulmonary embolism, is correlated with negative outcomes following ICH. Due to the risk of hematoma expansion associated with the use of VTE chemoprophylaxis, there remains significant debate about the optimal timing for its initiation following ICH. We analyzed the risk of early chemoprophylaxis on hematoma expansion following ICH. METHODS: We performed a retrospective analysis of patients presenting with spontaneous ICH at single institution between 2011 and 2018. The rate of hematoma expansion was compared between patients that received early chemoprophylaxis (on admission) and those that received conventional chemoprophylaxis (>24 h). RESULTS: Data for 235 patients were available for analysis. Eleven patients (7.5%) in the early prophylaxis cohort and seven patients (8.0%) in the conventional prophylaxis cohort developed VTE (P = 0.9). Hematoma expansion also did not differ significantly (early 19%, conventional 23%, P = 0.5). CONCLUSION: The use of early chemoprophylaxis against venous thromboembolic events following ICH appears safe in our patient population without increasing the risk of hematoma expansion. Given the increased risk of poor outcome in the setting of VTE, early VTE chemoprophylaxis should be considered in patients who present with ICH. Larger, prospective, and randomized studies are necessary to better elucidate the risk of early chemoprophylaxis and potential reduction in venous thromboembolic events.

Off-Label Utilization of Syphontrak Catheter for Mechanical Thrombectomy in Acute Stroke.

BACKGROUND: It is not known whether aspiration-specific catheters are necessary for successful mechanical thrombectomy, but if not, off-label use of more versatile catheters could offer significant cost savings over specialized aspiration catheters. The Syphontrak (Depuy Synthes, Raynham, MA, USA) support catheter is designed for introduction of devices into distal neurovasculature but is not specifically indicated for use in mechanical thrombectomy. We sought to compare our experience using this catheter to historical controls to show the non-inferiority of aspiration achieved. METHODS: Data were collected retrospectively on patients who underwent mechanical thrombectomy using the Syphontrak catheter for aspiration at our institution. Patient demographics, procedure characteristics, and outcome information was recorded. Results were compared to five landmark studies on mechanical thrombectomy: MR CLEAN, ESCAPE, REVASCAT, SWIFT PRIME, and EXTEND-IA. RESULTS: There were 63 patients who underwent mechanical thrombectomy for anterior circulation ischemic stroke. Despite significantly older patients and greater time from symptom onset to groin puncture, Thrombolysis in Cerebral Infarction grade 2B or 3 reperfusion was achieved in significantly more patients than in MR CLEAN, ESCAPE, and REVASCAT. Development of symptomatic intracranial hemorrhage occurred in 6.4% of patients, which was not significantly different from MR CLEAN, ESCAPE, REVASCAT, and EXTEND-IA. Mortality was 19.1%, which was not significantly different from any of the trials. CONCLUSIONS: These data support the off-label use of distal intracranial support catheters for this mechanical thrombectomy, which may result in significant cost savings over aspiration-specific catheters, especially in low-volume centers.

Laboratory assessments of therapeutic platelet inhibition in endovascular neurosurgery: complication prediction using the VerifyNow P2Y12 assay and thromboelastography with platelet mapping.

OBJECTIVE: Inhibition of platelet aggregation is universally used to prevent thromboembolic complications related to stent placement in endovascular neurosurgery, but excessive inhibition potentiates hemorrhagic complications. Previously, the authors demonstrated that two different commercially available measures of adenosine diphosphate (ADP)-dependent platelet inhibition-the VerifyNow P2Y12 clopidogrel assay (measured in platelet reactivity units [PRU]) and maximal amplitude (MA) attributable to ADP activity (MA-ADP) derived from thromboelastography (TEG) with platelet mapping (PM)-yielded wildly different results. This study sought to analyze observed complications to quantify the ideal therapeutic windows for both tests. METHODS: Ninety-one patients with simultaneous or near-simultaneous PRU and TEG-PM results who underwent craniocervical endovascular stenting at the authors' institution between September 2015 and November 2017 were identified and retrospectively enrolled. From November 2017 until June 2019, 109 additional patients were prospectively enrolled. For this study, in-hospital thrombotic and hemorrhagic complications (both CNS and non-CNS) were tabulated, and receiver operating characteristic (ROC) curve analysis was used to identify threshold values of the PRU and MA-ADP for predicting each type of complication. RESULTS: Of the 200 patients enrolled, 7 were excluded because of anemia or thrombocytopenia outside of the test manufacturer's specified ranges and 1 was excluded because they did not have a TEG-PM result. Including complications of all severities, there were a total of 15 CNS thrombotic complications, 1 access-site thrombotic complication, 3 CNS hemorrhages, 8 access-site hemorrhagic complications, and 3 hemorrhagic complications not affecting either the CNS or the access site. ROC curve analysis yielded therapeutic threshold values of 118-144 PRU. The results demonstrated PRU has a significant dose-dependent effect on the rates of thrombosis and hemorrhage. Logistic regression models did not demonstrate statistically significant relationships between the MA-ADP and either thrombosis or hemorrhage. ROC analysis based on these models is of little value and did not identify significant threshold values for MA-ADP. CONCLUSIONS: There continues to be poor correlation between the results of TEG-PM and PRU. PRU accurately predicted complications, with a relatively narrow ideal value range of 118-144. The MA-ADP alone does not appear able to accurately predict either hemorrhagic or thrombotic complications in this group.

Solitaire Stent Retriever Mechanical Thrombectomy in a 6-Month-Old Patient with Acute Occlusion of the Internal Carotid Artery Terminus: Case Report.

BACKGROUND: Endovascular mechanical thrombectomy (MT) performed with stent retriever devices have proven efficacious in the treatment of adult patients with acute cerebral ischemia resulting from large-vessel occlusion. Recently, reports describing the use of MT in pediatric large-vessel occlusion have increased. However, these case reports are generally limited to older children and teenagers. CASE DESCRIPTION: We report the use of a Solitaire (Medtronic, Minneapolis, Minnesota, USA) stent retriever for thrombectomy and revascularization of the right middle cerebral artery) in a 6-month-old patient. CONCLUSIONS: To our knowledge, this is the youngest patient reported to be treated with MT using a stent retriever. This case adds to the growing literature that supports the use of MT as a stroke intervention in pediatric patients.

Single-Center Case Series of Temporary Stent Assistance for Coiling of Acutely Ruptured Aneurysms.

BACKGROUND: Wide-necked intracranial aneurysms continue to pose a challenge for endovascular surgeons. Flow diversion and stent-assisted coiling are 2 techniques that have improved the ability to manage these lesions, but these require the use of dual antiplatelet therapy. In patients with aneurysmal subarachnoid hemorrhage, dual antiplatelet therapy is relatively contraindicated, and many surgeons prefer to use open techniques or balloon assistance for coiling, although at times the latter is not feasible. We describe temporary stent assistance using retrievable stents for coiling of ruptured intracranial aneurysms as an endovascular management option. METHODS: Surgeon case logs were retrospectively reviewed for cases of temporary stent assistance for aneurysm coiling. Cases were identified and compiled into a case series. RESULTS: Seven cases were identified, including 6 using the Solitaire FR device in an off-label manner as a temporary stent for assistance with coiling of wide-necked aneurysms. One patient experienced intraoperative aneurysm rupture (planned stent coiling; stent placement aborted after rupture), but otherwise no hemorrhagic complications were noted. Two patients experienced radiographic thromboembolic complications, with 1 patient requiring intervention during the index operation, but neither patient experienced demonstrable neurologic deficits postoperatively. After mean follow-up of 9 months, the average Glasgow Coma Scale score was 14, and the average modified Rankin Scale score was 1.2. CONCLUSIONS: Stents and stent retrievers can be temporarily used for technically challenging aneurysms as an alternative to balloon assistance for treatment of ruptured intracranial aneurysms without needing to use dual antiplatelet therapy.

Direct enhancement of readiness for wartime critical specialties by civilian-military partnerships for neurosurgical care: residency training and beyond.

Military neurosurgery has played an integral role in the development and innovation of neurosurgery and neurocritical care in treating battlefield injuries. It is of paramount importance to continue to train and prepare the next generation of military neurosurgeons. For the Army, this is currently primarily achieved through the military neurosurgery residency at the National Capital Consortium and through full-time out-service positions at the Veterans Affairs-Department of Defense partnerships with the University of Florida, the University of Texas-San Antonio, and Baylor University. The authors describe the application process for military neurosurgery residency and highlight the training imparted to residents in a busy academic and level I trauma center at the University of Florida, with a focus on how case variety and volume at this particular civilian-partnered institution produces neurosurgeons who are prepared for the complexities of the battlefield. Further emphasis is also placed on collaboration for research as well as continuing education to maintain the skills of nondeployed neurosurgeons. With ongoing uncertainty regarding future conflict, it is critical to preserve and expand these civilian-military partnerships to maintain a standard level of readiness in order to face the unknown with the confidence befitting a military neurosurgeon.

Corrigendum to "Vertebral Arteriovenous Fistula: An Unwelcome Thrill".

[This corrects the article DOI: 10.1155/2017/8386459.].

Laboratory assessments of therapeutic platelet inhibition in endovascular neurosurgery: comparing results of the VerifyNow P2Y12 assay to thromboelastography with platelet mapping.

OBJECTIVEInhibition of platelet aggregation is vital to preventing thromboembolic complications related to stent placement in endovascular neurosurgery, but excessive inhibition potentiates hemorrhagic complications. Recent evidence suggests an ideal inhibition range of 70-150 P2Y12 response units (PRU) as measured on the VerifyNow assay, which relies on photometric measurements of platelet aggregation. Thromboelastography (TEG) with platelet mapping (PM) is an alternative assay that directly measures clot formation and mechanical strength. This study compares the results of PRU to TEG-PM.METHODSPatients with simultaneous or near-simultaneous PRU and TEG-PM results who underwent cervical carotid artery stenting, intracranial stent-assisted aneurysm coiling, or flow diversion at the authors' institution between August 2015 and November 2016 were identified. PRU results were compared with the TEG maximal amplitude (MA) attributable to adenosine diphosphate (ADP) activity (MA-ADP) as measured by TEG-PM. Platelet inhibition was considered therapeutic for MA-ADP values < 50 mm or PRU < 194. The Pearson correlation coefficient was calculated, and the sensitivity and specificity of PRU were calculated assuming that the results of TEG-PM reflected the true degree of platelet inhibition.RESULTSTwenty-three patients were identified with a total of 37 matched sets of TEG-PM and PRU. Three of these pairs were excluded due to anemia outside of the PRU manufacturer's recommended range. The Pearson correlation coefficient for these values was 0.50 (p = 0.0026). The prevalence of clopidogrel nonresponders determined by TEG-PM (9%) matched reported rates (5%-12%); PRU demonstrated much higher prevalence (39%). For detecting a therapeutic level of platelet inhibition, PRU demonstrated a sensitivity of 0.59, specificity of 0.50, positive predictive value of 0.95, and negative predictive value of 0.07. Ideal inhibition was concordant in only 25% of observations in which at least one of the results was ideal.CONCLUSIONSAgreement between TEG-PM and PRU regarding the degree of platelet inhibition is poor. PRU likely overestimates clopidogrel resistance, as 93% of patients with PRU > 194 demonstrate a therapeutic level of platelet inhibition on TEG.

The Patient Size Setting: A Novel Dose Reduction Strategy in Cerebral Endovascular Neurosurgery Using Biplane Fluoroscopy.

BACKGROUND: In some fluoroscopy machines, the dose-rate output of the fluoroscope is tied to a selectable patient size. Although patient size may play a significant role in visceral or cardiac procedures, head morphology is less variable, and high dose outputs may not be necessary even in very obese patients. We hypothesized that very small patient size setting can be used to reduce dose for cerebral angiography without compromising image quality. METHODS: Patients who underwent endovascular neurosurgical procedures during the 2015-2016 academic year were identified, and estimated procedural air kerma (AK) was tabulated retrospectively. Technologists were instructed to begin using the very small patient size setting for all procedures performed using our Philips Allura Xper FD20 biplane fluoroscopy system beginning in March 2016. No changes were made in a second procedure room using a Toshiba Infinix system. Student t tests and logistic regression models were used to compare radiation exposure before and after March 1, 2016, for both machines. RESULTS: For diagnostic cerebral angiograms performed on the Philips system (n = 302), AK was reduced by approximately 17% (1277 vs. 1061 mGy; P = 0.0006.) Changes in table height, total fluoroscopy time, patient weight, and body mass index did not contribute to this difference. No significant change was seen in total AK using the Toshiba system (n = 237). Blinded review by a neuroradiologist did not demonstrate any change in image quality. CONCLUSIONS: Using the very small patient size reduces fluoroscopy dose by 17% for cerebral angiography without impacting image quality.

Vertebral Arteriovenous Fistula: An Unwelcome Thrill.

Cervical vertebral AV fistulae are uncommon vascular lesions involving abnormal communication between the extradural vertebral artery and surrounding venous structures. We examine the case of a female evaluated in the emergency department with a vertebral AV fistula presenting classically as pulsatile tinnitus and later successfully treated with standard endovascular techniques. A discussion on the etiology, pathophysiology, and management of vertebral AV fistulae follows.

Complications After In Vivo and Ex Vivo Autologous Bone Flap Storage for Cranioplasty: A Comparative Analysis of the Literature.

INTRODUCTION: The most common bone flap storage strategies after decompressive hemicraniectomy for malignant intracranial hypertension include freezer cryopreservation (CP) and subcutaneous abdominal implantation (AP). Numerous series have reported on patient outcomes after cranioplasty in terms of infection, cosmesis, and resorption. This meta-analysis compares published outcomes of bone flap CP and subcutaneous storage with respect to efficacy and complication risk in patients undergoing cranioplasty after hemicraniectomy. METHODS: A systematic review was performed using PubMed-searchable studies that included bone flap storage methods and outcome data for cranioplasties performed between 1975 and 2015. RESULTS: A total of 48 studies including 5346 patients were identified that met the inclusion criteria. Of these patients, 4096 underwent cranioplasty with an autologous flap. Mean bone flap storage times for CP and AP flaps were 69.9 and 69.7 days. Mean follow-up time for CP and AP flaps was 16.9 and 16.5 months. No statistically significant differences were found when comparing CP with subcutaneous storage of bone flaps with respect to percentage of patients developing infection (7.3% vs. 7.1%), percentage of patients needing revision surgery (15.9% vs. 7.6%), and percentage of patients experiencing resorption (9.7% vs. 7.7%). CONCLUSIONS: This is the largest and most robust review comparing published outcomes of CP and subcutaneous storage of bone flaps in patients who have undergone decompressive hemicraniectomy. This review found no statistically significant differences in clinical outcomes (infection, resorption, reoperation) when comparing storage methods for bone flap preservation. This study suggests that both strategies may be used safely and successfully.

Unilateral Pedicle Screw Fixation is Associated with Reduced Cost and Similar Outcomes in Selected Patients Undergoing Minimally Invasive Transforaminal Lumbar Interbody Fusion for L4-5 Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective study of 24 patients who underwent either a bilateral or unilateral TLIF procedure for the treatment of degenerative spondylolisthesis. OBJECTIVE: To analyze differences in cost and outcome between patients undergoing minimally invasive transforaminal lumbar interbody fusion (mi-TLIF) with unilateral or bilateral pedicle screw fixation for L4-5 degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Lumbar fusion surgeries, including the TLIF procedure, have been shown to be an effective treatment for leg and low back pain caused by degenerative spondylolisthesis. Some studies have shown TLIF surgeries to be cost-effective, but there is still a paucity of data and no consensus. Unilateral TLIFs can provide the same benefits as bilateral TLIFs, but come with additional benefits of a less invasive surgery. METHODS: We retrospectively analyzed a consecutive series of patients with L4-5 degenerative stenosis and spondylolisthesis who either received a unilateral or bilateral mi-TLIF, paying particular attention to hospital cost and clinical outcome. Of the 33 patients eligible for analysis, we were able to obtain appropriate clinical and radiographic follow-up data on 24 patients (72.7%), 14 patients who underwent unilateral fixation, and 10 patients who underwent bilateral fixation. RESULTS: The cohorts were similar with regard to age, comorbidities, and demographics. Most patients reported good or excellent results, and there were no significant differences between the cohorts with regard to clinical outcome. There was one interbody graft extrusion in the unilateral cohort that required explantation, but no other hardware failures. Hospital cost was significantly lower in the unilateral cohort, and hardware savings accounted for only part of the difference. CONCLUSION: Unilateral pedicle screw fixation is an acceptable surgical strategy in patients with stable L4-5 degenerative spondylolisthesis undergoing mi-TLIF. In our series, unilateral fixation led to significant hospital cost savings without compromising clinical or radiographic outcomes.

Establishing Standard Performance Measures in Adult Traumatic Brain Injury Patients.

BACKGROUND: The Agency for Healthcare Research and Quality patient safety indicators (PSIs) and Centers for Medicare and Medicaid Services hospital-acquired conditions (HACs) are publicly reported metrics that illustrate the overall quality of care provided at an institution. The national incidences of PSIs and HACs in traumatic brain injury (TBI) patients were estimated using the Nationwide Inpatient Sample database. OBJECTIVE: To establish baseline incidences of PSIs and HACs among surgical TBI patients treated at nonfederal hospitals in the United States, and to identify patient factors contributing to these adverse events. METHODS: The Nationwide Inpatient Sample database was queried for patients admitted with International Classification of Diseases, Ninth Revision diagnosis codes consistent with TBI between 2002 and 2011. The incidences of PSIs and HACs were estimated for TBI patients and evaluated for correlation with multiple factors, including comorbidity score, teaching hospital status, and insurance status. RESULTS: There were 15403 total PSIs among 24012 TBI patients. There were only 165 HACs among 24012 TBI patients. Only sepsis, deep vein thrombosis, and pressure ulcers occurred in more than 1% of patients. Patient age, sex, comorbidity score, and teaching hospital status were all found to significantly impact PSI incidence. Comorbidity score was found to significantly impact HAC incidence. Compared with private insurance, Medicaid patients developed significantly more HACs. CONCLUSION: These data may be used as reference values for hospitals reporting their own rates and seeking to improve the quality of care they provide for TBI patients.

Management of low-grade third ventricular ependymomas in adults by endoscopic biopsy followed by gamma knife radiosurgery.

BACKGROUND: Third ventricular ependymomas in adults are rare lesions for which the optimal management strategy has not been determined. OBJECTIVES: We describe our results using a strategy of endoscopic biopsy followed by gamma knife radiosurgery in two patients with low-grade (World Health Organization [WHO] grade II) third ventricular ependymomas. METHODS: A retrospective analysis of clinical notes, operative records, and neuroimaging was performed for the two patients in this study. The patients both presented with obstructive hydrocephalus and had endoscopic third ventriculostomy performed along with endoscopic tumor biopsy. In both patients the pathology revealed papillary ependymoma WHO grade II. In one patient the endoscopic third ventriculostomy failed, and ventriculoperitoneal shunt placement was necessary. Postoperatively, gamma knife radiosurgery was performed at 1 and 4 months, respectively. RESULTS: Both patients in the study experienced symptom resolution following treatment of the hydrocephalus. They returned to their preoperative level of social and occupational function. There was tumor enlargement in one patient in the interval between the initial surgery and the gamma knife treatment. However, neither tumor has enlarged since gamma knife treatment with follow-up of 35 and 41 months, respectively. CONCLUSIONS: The strategy of endoscopic biopsy followed by gamma knife radiosurgery for adult WHO grade II third ventricular ependymomas has produced acceptable clinical results 3 years posttreatment. Stereotactic radiosurgery without prior microsurgical resection has not previously been reported in these tumors. Longer follow-up is required to evaluate the durability of this treatment.

Incidental discovery of subtle-variant septooptic dysplasia in an adult with headaches: a novel case with pathophysiologic implications.

Septooptic dysplasia (SOD) is a congenital central nervous system malformation syndrome classically associated with the triad of agenesis of the septum pellucidum, optic nerve hypoplasia, and pituitary abnormalities. It has been suggested that SOD may result from in utero vascular insults. We present the case of an adult male with personal and family histories of intracranial vascular pathology in whom SOD was incidentally discovered, and we describe how the specific abnormalities in this case could be related to vascular pathology.

Syk regulation of phosphoinositide 3-kinase-dependent NK cell function.

Emerging evidence suggests that NK-activatory receptors use KARAP/DAP12, CD3zeta, and FcepsilonRIgamma adaptors that contain immunoreceptor tyrosine-based activatory motifs to mediate NK direct lysis of tumor cells via Syk tyrosine kinase. NK cells may also use DAP10 to drive natural cytotoxicity through phosphoinositide 3-kinase (PI3K). In contrast to our recently identified PI3K pathway controlling NK cytotoxicity, the signaling mechanism by which Syk associates with downstream effectors to drive NK lytic function has not been clearly defined. In NK92 cells, which express DAP12 but little DAP10/NKG2D, we now show that Syk acts upstream of PI3K, subsequently leading to the specific signaling of the PI3K-->Rac1-->PAK1-->mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase-->ERK cascade that we earlier described. Tumor cell ligation stimulated DAP12 tyrosine phosphorylation and its association with Syk in NK92 cells; Syk tyrosine phosphorylation and activation were also observed. Inhibition of Syk function by kinase-deficient Syk or piceatannol blocked target cell-induced PI3K, Rac1, PAK1, mitogen-activated protein/ERK kinase, and ERK activation, perforin movement, as well as NK cytotoxicity, indicating that Syk is upstream of all these signaling events. Confirming that Syk does not act downstream of PI3K, constitutively active PI3K reactivated all the downstream effectors as well as NK cytotoxicity suppressed in Syk-impaired NK cells. Our results are the first report documenting the instrumental role of Syk in control of PI3K-dependent natural cytotoxicity.