Arteriovenous malformation presenting as complex regional pain syndrome: illustrative case.

BACKGROUND: Complex regional pain syndrome (CRPS) is typically described as a peripheral nerve disorder in which exaggerated allodynia and hyperalgesia follow a minor injury. Some researchers propose a central mechanism, although current evidence is lacking. OBSERVATIONS: A 14-year-old female presented with classic CRPS symptoms of left upper-extremity weakness and hyperalgesia after a bout of sharp pain in her thumb while shoveling snow. A possible seizure prompted magnetic resonance imaging, revealing a right frontal Spetzler-Martin grade II arteriovenous malformation (AVM) adjacent to the primary motor cortex. Brodmann areas 1, 3a, and 3b, which are responsible for localizing and processing burning and painful sensations, were also involved. The patient underwent transarterial Onyx embolization in two sessions and microsurgical resection, after which her CRPS symptoms completely resolved. LESSONS: To our knowledge, this is the first reported case of a cerebral AVM presenting as CRPS, which supports a central mechanism. The authors propose that rapid growth of the AVM led to a vascular steal phenomenon of surrounding parenchyma, which disrupted the patient's normal motor function and nociceptive processing. Further validation in other series is needed.

Stenting for Traumatic Pseudoaneurysms of the Cervical Internal Carotid Artery: Case Report and Systematic Review.

BACKGROUND: The optimal stenting approach for traumatic pseudoaneurysms (PSA) of the extracranial internal carotid artery (ICA) remains underinvestigated. We present a case of a traumatic pseudoaneurysm of the extracranial ICA managed with stenting and review of prior published similar cases. METHODS: The systematic review followed PRISMA-S guidelines and included studies that investigated traumatic pseudoaneurysms of the extracranial ICA managed by stent placement. Statistical analysis assessed the association between the type of injury and stent type, dual antiplatelet therapy (DAPT) duration, and clinical presentation, and the association between stent type and DAPT duration. RESULTS: Our search yielded 82 publications with 135 patients with extracranial ICA PSA treated with stenting. The odds of neck hematoma presentation was 12.2 times greater for patients with penetrating rather than blunt injuries (P = 0.000002). Covered stents had 2.02 times higher odds of use for penetrating rather than blunt injuries compared to bare metal stents. (P = 0.0029). Shorter duration DAPT was seen with bare metal stents having 1.25 higher odds of DAPT duration less than one month compared to covered (P = 0.001). CONCLUSIONS: In traumatic extracranial ICA pseudoaneurysms, covered stents are used more commonly for penetrating injuries compared to blunt injuries. Penetrating injuries are more strongly associated with the presentation of a hematoma compared to blunt injuries. Stent type may influence the recommended DAPT duration. Surgeons should consider these findings when selecting stent type and DAPT duration with patients presenting with traumatic extracranial ICA pseudoaneurysm.

Cerebral arterial vasospasm complicating supratentorial meningioma resection: illustrative cases.

BACKGROUND: Cerebral arterial vasospasm is a rare complication after supratentorial meningioma resection. The pathophysiology of this condition may be similar to vasospasm after aneurysmal subarachnoid hemorrhage, and treatment options may be similar. OBSERVATIONS: The authors present two cases of cerebral vasospasm after supratentorial meningioma resection and perform a systematic literature review of similar cases. LESSONS: Cerebral arterial vasospasm after supratentorial meningioma resection may be associated with significant morbidity due to cerebral ischemia if not addressed in a timely manner. Treatment paradigms may be adopted from the management of arterial vasospasm associated with subarachnoid hemorrhage.

Effect of Stent Porosity, Platelet Function Test Usage, and Dual Antiplatelet Therapy Duration on Clinical and Radiographic Outcomes After Stenting for Cerebral Aneurysms: A Meta-Analysis.

BACKGROUND: The use of stents with various porosities for treating cerebral aneurysms requires dual antiplatelet therapy (DAPT) without clear guidelines on the utility of platelet function tests (PFTs) and the duration of DAPT. We sought to determine the effects of stent porosity, PFT usage, and DAPT duration on the radiographic and clinical outcomes after stenting of cerebral aneurysms. METHODS: PubMed was searched on March 29, 2021 for studies of cerebral aneurysm stenting that had specified the stent type and DAPT duration. A random effects meta-analysis was used to measure the prevalence of nonprocedural thrombotic and hemorrhagic events, clinical outcomes, aneurysm occlusion, and in-stent stenosis stratified by stent porosity, PFT usage, and DAPT duration. RESULTS: The review yielded 105 studies (89 retrospective and 16 prospective) with 117 stenting cohorts (50 high porosity, 17 intermediate porosity, and 50 low porosity). In the high-, intermediate-, and low-porosity stenting cohorts, PFT usage was 26.0%, 47.1%, and 62.0% and the mean DAPT duration was 3.51 ± 2.33, 3.97 ± 1.92, and 5.18 ± 2.27 months, respectively. The intermediate-porosity stents showed a reduced incidence of hemorrhagic events (π = 0.32%) compared with low-porosity stents (π = 1.36%; P = 0.01) and improved aneurysm occlusion (π = 6.18%) compared with high-porosity stents (π = 14.42%; P = 0.001) and low-porosity stents (π = 11.71%; P = 0.04). The prevalence of in-stent stenosis was lower for the intermediate-porosity (π = 0.57%) and high-porosity (π = 1.51%) stents than for the low-porosity stents (π = 3.30%; P < 0.05). PFT use had resulted in fewer poor clinical outcomes (π = 3.54%) compared with those without PFT use (π = 5.94%; P = 0.04). The DAPT duration had no effect on the outcomes. CONCLUSIONS: In the present meta-analysis, which had selected for studies of cerebral aneurysm stenting that had reported the DAPT duration, intermediate-porosity stents and PFT use had resulted significantly improved outcomes. No effect of DAPT duration could be detected.

Comparison of transarterial n-BCA and Onyx embolization of brain arteriovenous malformations: A single-center 18-year retrospective analysis.

OBJECTIVE: Brain arteriovenous malformations (AVM) are commonly treated with endovascular embolization. Due to the rapid evolution of endovascular technology and lack of consistent practice guidelines regarding AVM embolization, further study of AVM embolization outcomes is warranted. METHODS: We conducted a retrospective review of AVMs embolized at a single center from 2002-2019. Patient demographics, AVM characteristics, intention of embolization, and angiographic and clinical outcome after embolization were recorded. We compared the embolization results of those treated with n-butyl cyanoacrylate (n-BCA) and Onyx. RESULTS: Over an 18-year period at our institution, 30 (33%) of 92 AVMs were treated with embolization. n-BCA was used in 12 cases and Onyx in 18 cases. Eighty-seven pedicles were embolized over 47 embolization sessions. Fifty percent of AVMs treated with n-BCA underwent more than one embolization session compared to 22% when Onyx was used. The median total percent volume reduction in the n-BCA AVMs was 52% compared to 51% in Onyx AVMs. There were 2 periprocedural complications in the n-BCA cohort and none in the Onyx cohort. CONCLUSIONS: In this small retrospective series, Onyx and n-BCA achieved similar occlusion results, although n-BCA required more sessions and pedicles embolized to do so.

Endovascular catheter manometry reliability: a benchtop validation study.

OBJECTIVE: Catheter manometry is used frequently in neuroendovascular surgery for assessing cerebrovascular pathology. The accuracy of pressure data with different catheter setups requires further validation. METHODS: In a silicone human vascular model with a pulsatile pump, pressure measurements were taken through multiple arrangements of 2 guide catheters and 6 microcatheters. The systolic pressure, diastolic pressure, mean pressure, pulse pressure, and area under the curve of the waveform were recorded through catheters with controls at arterial blood pressure ranges. Linear regression modeling was performed, correlating transduction area and relative pulse pressure. Thresholds for acceptable accuracy were ≥ 90%. RESULTS: Mean pressure demonstrated < 4% variation between all 24 catheter setups and respective controls. A strong linear correlation (r2 = 0.843, p < 0.0005) between microcatheter transduction area and relative pulse pressure with a threshold of 0.50 mm2 was seen (i.e., 0.031-inch inner diameter [ID]). For guide catheters with indwelling microcatheters, there was also a strong linear correlation (r2 = 0.840, p < 0.0005) of transduction area to pulse pressure. The guide catheters with obstructing microcatheters required a transduction area over fourfold higher compared with unobstructed microcatheters (2.21 mm2 vs 0.50 mm2). CONCLUSIONS: Mean pressure measurements are accurate through microcatheters as small as 0.013-inch ID. Pulse pressure and waveform morphology may require a microcatheter ≥ 0.031-inch ID to achieve 90% accuracy, although the 0.027-inch ID microcatheter reached 85% accuracy. A 0.070-inch guide catheter with a microcatheter ≤ 0.042-inch outer diameter (e.g., Marksman 0.027-inch ID or smaller) allows accurate transduction of pulse pressure. Further validation of these benchtop findings is necessary before application in a clinical setting.

Angioarchitectural features amongst patients with unruptured brain arteriovenous malformations presenting with headache: findings from a single center retrospective review of 76 patients.

BACKGROUND: Brain arteriovenous malformations (AVMs) consist of abnormal connections between arteries and veins via an interposing nidus. While hemorrhage is the most common presentation, unruptured AVMs can present with headaches, seizures, neurological deficits, or be found incidentally. It remains unclear as to what AVM characteristics contribute to pain generation amongst unruptured AVM patients with headaches. METHODS: To assess this relationship, the current study evaluates angiographic and clinical features amongst patients with unruptured brain AVMs presenting with headache. Loyola University Medical Center medical records were queried for diagnostic codes corresponding to AVMs. In patients with unruptured AVMs, we analyzed the correlation between the presenting symptom of headache and various demographic and angiographic features. RESULTS: Of the 144 AVMs treated at our institution between 1980 and 2017, 76 were unruptured and had sufficient clinical data available. Twenty-three presented with headaches, while 53 patients had other presenting symptoms. Patients presenting with headache were less likely to have venous stenosis compared to those with a non-headache presentation (13 % vs. 36 %, p = 0.044). CONCLUSIONS: Our study suggests that the absence of venous stenosis may contribute to headache symptomatology. This serves as a basis for further study of correlations between AVM angioarchitecture and symptomatology to direct headache management in AVM patients.

Machine learning models improve prediction of large vessel occlusion and mechanical thrombectomy candidacy in acute ischemic stroke.

BACKGROUND AND PURPOSE: Early identification of large vessel occlusions (LVO) and timely recanalization are paramount to improved clinical outcomes in acute ischemic stroke. A stroke assessment that maximizes sensitivity and specificity for LVOs is needed to identify these cases and not overburden the health system with unnecessary transfers. Machine learning techniques are being used for predictive modeling in many aspects of stroke care and may have potential in predicting LVO presence and mechanical thrombectomy (MT) candidacy. METHODS: Ischemic stroke patients treated at Loyola University Medical Center from July 2018 to June 2019 (N = 286) were included. Thirty-five clinical and demographic variables were analyzed using machine learning algorithms, including logistic regression, extreme gradient boosting, random forest (RF), and decision trees to build models predictive of LVO presence and MT candidacy by area of the curve (AUC) analysis. The best performing model was compared with prior stroke scales. RESULTS: When using all 35 variables, RF best predicted LVO presence (AUC = 0.907 ± 0.856-0.957) while logistic regression best predicted MT candidacy (AUC = 0.930 ± 0.886-0.974). When compact models were evaluated, a 10-feature RF model best predicted LVO (AUC = 0.841 ± 0.778-0.904) and an 8-feature RF model best predicted MT candidacy (AUC = 0.862 ± 0.782-0.942). The compact RF models had sensitivity, specificity, negative predictive value and positive predictive value of 0.81, 0.87, 0.92, 0.72 for LVO and 0.87, 0.97, 0.97, 0.86 for MT, respectively. The 10-feature RF model was superior at predicting LVO to all previous stroke scales (AUC 0.944 vs 0.759-0.878) and the 8-feature RF model was superior at predicting MT (AUC 0.970 vs 0.746-0.834). CONCLUSION: Random forest machine learning models utilizing clinical and demographic variables predicts LVO presence and MT candidacy with a high degree of accuracy in an ischemic stroke cohort. Further validation of this strategy for triage of stroke patients requires prospective and external validation.

Primary Intradural Extramedullary Sporadic Spinal Hemangioblastomas: Case Report and Systematic Review.

BACKGROUND: Hemangioblastomas are benign vascular neoplasms of the central nervous system that may occur sporadically or in association with Von Hippel-Lindau disease. A minority of these lesions can occur in the spine, mostly as intramedullary masses. The authors present a rare case of primary sporadic spinal hemangioblastoma occurring as an intradural extramedullary (IDEM) lesion. Diagnostic workup and surgical management of the patient are described. METHODS: A systematic MEDLINE search was conducted using the keywords "hemangioblastoma" and "intradural extramedullary," "extramedullary," or "cauda equina." Clinicopathological characteristics and outcomes of the present case were reviewed and compared with those in the literature. RESULTS: A 72-year-old man was found to have an IDEM lesion in his cervical spine after presenting with neck and shoulder pain. Gross total resection was successfully performed with sacrifice of an involved dorsal nerve rootlet. Screening for Von Hippel-Lindau was negative. Thirty-three additional patients with sporadic IDEM hemangioblastomas are reported in the literature. There was a slight male preponderance (54%) with a median age of 52 years. Patients presented with pain (54%), radiculopathy (33%), or myelopathy (32%). The majority of lesions were located in the lumbosacral spine (56%). All patients underwent maximal safe resection with stable or improved clinical status. CONCLUSION: Primary IDEM hemangioblastomas are a rare entity. Differential diagnosis includes other IDEM lesions, such as schwannomas, meningiomas, or some vascular malformations. Resection of these sporadic tumors can be safely performed and result in improvement of neurologic deficits associated with mass effect from the tumor with low likelihood of recurrence.

Coaxial Access for Microcatheter Stabilization During Aneurysm Coiling: 2-Dimensional Operative Video.

Coaxial support is a fundamental technique utilized by neurointerventionalists to optimize distal catheter control within the intracranial circulation. Here we present a 41-yr-old woman with a previously coiled ruptured anterior communicating artery aneurysm with progressive recurrence harboring tortuous internal carotid anatomy to demonstrate the utility of coaxial support. Raymond-Roy classification of initial aneurysm coiling of class 1 resulted as class 3b over the 21 mo from initial treatment.1 The patient consented to stent-assisted coiling for retreatment of this aneurysm. Coaxial support was advanced as distally as possible in the proximal vasculature to improve catheter control, reducing dead space within which the microcatheter could move, decreasing angulations within proximal vasculature, limiting the movement of the native vessels, and providing a surface of lower friction than the endothelium. As the risk of recurrent subarachnoid hemorrhage in previously treated coiled aneurysms approaches 3%, retreatment occurs in 16.4% within 6 yr2 and in 17.4% of patients within 10 yr.3 Rerupture is slightly higher in patients who underwent coiling vs clipping, with the rerupture risk inversely proportional to the degree of aneurysm occlusion,4 further substantiating that coaxial support provides technical advantage in selected patients where additional microcatheter control is necessary for optimal occlusion. Pitfalls of this technique include vasospasm and vascular injury, which can be ameliorated by pretreatment of the circulation with vasodilators to prevent catheter-induced vasospasm. This case and model demonstration illustrates the technique of coaxial access in the stent-assisted coiling of a recurrent anterior communicating artery aneurysm and identification and management of catheter-induced vasospasm.

Trigeminal Neuralgia Secondary to Cerebellar Arteriovenous Malformation: A Report of Two Cases.

Trigeminal neuralgia (TN) secondary to cerebellar arteriovenous malformation (cAVM) is a rare condition with only few reports existing in the literatures. Given to its rarity, the treatment armamentarium is still controversial. We reported our experiences treated two cases of TN secondary to cAVM using different strategies. The first case was successfully treated by a combination of gamma knife radiosurgery and microvascular decompression (MVD) of the trigeminal nerve. The second case was successfully treated by one-step microsurgical AVM resection and MVD of the trigeminal nerve. Postoperative immediate pain relief was achieved in both patients. Microsurgical procedure is still playing an important role in treating TN secondary to cAVM.

'Railroad switch' technique for stent-assisted coil embolization of a wide-neck bifurcation intracranial aneurysm: technical note.

Preservation of the posterior cerebral arteries during endovascular treatment of wide-neck basilar bifurcation aneurysms remains a technical challenge despite recent device innovations. We present a novel stent deployment technique, the 'railroad switch', to protect both posterior cerebral arteries during treatment of a recurrent basilar bifurcation aneurysm. Following asymmetric basilar-posterior cerebral artery stent deployment, favoring distal placement in a posterior cerebral artery, advancement of a jailed microcatheter will advance the proximal stent into the aneurysm, protecting both posterior cerebral arteries and the native basilar terminus. This novel maneuver offers interventionalists another application of commonly used intracranial stents for endovascular management of complex basilar bifurcation aneurysms.

Mercury vs. Water: An Analysis of Multi-Institutional Survey Data Assessing Intracranial Pressure Unit of Measure Awareness.

BACKGROUND: Intracranial pressure (ICP) reporting impacts neurosurgical care. Millimeters of mercury (mmHg) and centimeters of water (cmH2O) are both used to report ICP in clinical practice and the literature. In this study, we investigated ICP unit of measure awareness in the neurosurgical community. METHODS: A survey was conducted at four US academic neurosurgery departments asking the following questions: What is your threshold for a concerning ICP? How many minutes is that ICP sustained for you to be concerned? What unit are you implying when you state that ICP? What unit of measure is an ICP reported on the monitor when transduced? When setting an external ventricular drain Becker bag level, what unit of measure do you set it to? Do you ever manually check an ICP based on a column of cerebrospinal fluid? How many cmH2O is 20 mmHg? RESULTS: An ICP of 20 and sustained for five minutes were the two most common answers. Some 71% of residents and 34% of attendings reported using cmH2O as the unit of measure; 18% of residents and 24% of attendings implied different units when discussing ICP than the unit they thought was transduced; and 53% of residents and 34% of attendings did not know the transduced ICP unit of measure reported in their intensive care unit. CONCLUSIONS: Variability and discrepancies regarding the ICP unit of measure exist in academic neurosurgery departments. Clinicians should familiarize themselves with their hospital's practices. Institutions and all of medicine may consider standardizing the ICP unit of measure, using mmHg as a universal nomenclature.

Murphey's teat: history and insight into an enigmatic cerebrovascular eponym.

Dr. Francis Murphey of the Semmes-Murphey Clinic in Memphis recognized that a focal sacculation on the dome of an aneurysm may be angiographic evidence of a culpable aneurysm in the setting of subarachnoid hemorrhage with multiple intracranial aneurysms present. This has been referred to as a Murphey's "teat," "tit," or "excrescence." With variability in terminology, misspellings in the literature, and the fact that Dr. Murphey did not formally publish this important work, the authors sought to clarify the meaning and investigate the origins of this enigmatic cerebrovascular eponym.

Extracranial-to-Intracranial Bypass for Pressor Dependent Cerebrovascular Insufficiency: Modified Classification and Representative Case.

BACKGROUND: While some randomized clinical trials have reduced the indications for cerebral revascularization in the secondary prevention of ischemic stroke, a distinct subset of patients with blood pressure augmentation dependent cerebrovascular insufficiency due to large vessel occlusions remains unaddressed. With the recent paradigm shifts in acute ischemic stroke care, the role of extracranial to intracranial (EC-IC) bypass must be re-addressed when endovascular intervention is not a feasible option. We submit a refined classification of cerebrovascular insufficiency with a category called Pressor-Dependent Cerebrovascular Insufficiency (PD-CVI) for whom EC-IC bypass may be indicated. CLINICAL PRESENTATION: A 61-year-old female former smoker presented with one day of intermittent left faciobrachial weakness and was found to have middle cerebral artery and cervical internal carotid artery occlusions. On admission to the intensive care unit, she was found to have PD-CVI with an intravenous pressor dependent blood pressure threshold over which she had near resolution of her neurological deficits. With endovascular intervention precluded given the ICA occlusion, she underwent an urgent right sided EC-IC bypass. The procedure was without complication, with careful attention to maintaining hypertension perioperatively. She required no pressors postoperatively and was neurologically intact at three months post-operatively. CONCLUSION: With recent advances in acute ischemic stroke care, there remains a need for careful consideration of cerebral revascularization surgery in patients with evidence of PD-CVI who may be precluded from or failed endovascular intervention.

Fusiform dilatation of the internal carotid artery following childhood craniopharyngioma resection treated by endovascular flow diversion-A case report and literature review.

Fusiform dilatation of the internal carotid artery (FDICA) is a well-described radiographic finding following resection of childhood craniopharyngioma (CP). A 39-year-old woman with right-sided FDICA was successfully treated for lesion enlargement with endovascular flow diversion, which has not been described in the literature.

Should we still consider clips for basilar apex aneurysms? A critical appraisal of the literature.

BACKGROUND: Basilar apex aneurysms constitute 5-8% of all intracranial aneurysms, and their treatment remains challenging for both microsurgical and endovascular approaches. The perceived drawback of the microsurgical approach is its invasiveness leading to increased surgical morbidity. However, many high-volume centers have shown excellent clinical results with better occlusion rates compared to endovascular treatment. With endovascular therapy taking a larger role in the management of cerebral aneurysms, the future role of microsurgery for basilar apex aneurysm treatment is unclear. METHODS: We performed a literature search to review the microsurgical and endovascular outcomes for basilar apex aneurysms. RESULTS: Many studies have examined the efficacy of microsurgical and endovascular treatment for intracranial aneurysms, including large randomized trials such as ISAT and BRAT, prospective observational series such as ISUIA, and many single-center retrospective reviews. The recruitment number for posterior circulation aneurysms, specifically for basilar apex aneurysms, was limited in most prospective trials, thus failing to offer clear guidance on basilar apex aneurysm treatment. Recent single-center series report good clinical outcomes between 57-92% for surgical series and 73-96% in endovascular series. The durability of aneurysm occlusion remains superior in surgical cases. The techniques and devices in endovascular treatment have improved treatment aneurysm occlusion rates but more follow-up is needed to confirm long-term durability. CONCLUSIONS: Both microsurgical and endovascular approaches should be complementing each other to treat basilar apex aneurysms. Although endovascular therapy has taken a larger role in the treatment of basilar apex aneurysms, many indications still exist for the use of microsurgery. Advancements in microsurgical techniques and good case selection will allow for acceptably low morbidity after surgical treatment while maintaining its superior durability.

Angiographic "Blush" After Stereotactic Radiosurgery Ablation of Residual Arteriovenous Malformation in Pediatric Patient: Case Report and Review of Literature.

INTRODUCTION: While surgical resection remains a primary treatment for accessible arteriovenous malformations (AVMs), stereotactic radiosurgery (SRS) has become thoroughly integrated into the AVM armamentarium; however, delayed sequelae of this treatment have become evident with increased long-term follow-up. To our knowledge, this is the second case of an aberrant local arterial angiographic blush without early venous drainage or an associated lesion following AVM SRS. CASE DESCRIPTION: An 8-year-old female presented with a ruptured 4-cm right medial frontal periventricular Spetzler-Martin grade 3 AVM with isolated intraventricular hemorrhage. She underwent subtotal resection followed by SRS. Six years later, diagnostic cerebral angiography demonstrated a prominent arterial-phase filling microvasculature without early venous drainage in the region of the irradiated residual AVM nidus. CONCLUSION: Although there is a paucity of information on angiographic blush following AVM SRS, consensus in the literature suggests that without early venous drainage, these lesions appear to pose an insignificant threat to the patient. These angiographic findings may be on a spectrum of delayed cerebrovascular radiation changes, and thus indefinite follow-up may be considered, especially in pediatric patients.