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BACKGROUND Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare brain tumor only recently classified by the World Health Organization in 2016 and has few reports on its incidence in adults. OBSERVATIONS The authors describe a case of DLGNT presenting in a 47-year-old female with seizures, cranial neuropathies, and communicating hydrocephalus with rapid clinical progression. Workup demonstrated progressive leptomeningeal enhancement of the skull base, cranial nerves, and spine, and communicating hydrocephalus. Elevated serum rheumatological markers and early response to systemic corticosteroids and immunosuppressant therapy complicated the diagnosis. Multiple biopsy attempts were required to obtain diagnostic tissue. Pathology demonstrated hypercellularity surrounding leptomeningeal vessels with nuclear atypia, staining positive for GFAP, Olig2, S100, and synaptophysin. Molecular pathology demonstrated loss of chromosome 1p, BRAF overexpression but no rearrangement, and H3K27 mutation. Repeat cerebrospinal fluid (CSF) diversion procedures were required for hydrocephalus management due to high CSF protein content. LESSONS This report describes a rare, aggressive, adult presentation of DLGNT. Leptomeningeal enhancement and communicating hydrocephalus should raise suspicion for this disease process. Biopsy at early stages of disease progression is essential for early diagnosis and prompt treatment. Further study into the variable clinical presentation, histological and molecular pathology, and optimal means of diagnosis and management is needed.

Cerebral arteriovenous malformations (AVMs) have historically been considered congenital lesions with treatment options including surgery, radiation therapy, and observation. Spontaneous resolution of cerebral AVMs remains an exceedingly rare event with poorly understood pathophysiology.Herein we report a retrospective case review of a 28-year-old man with alcoholic cirrhosis who presented with a seizure 3 weeks after liver transplantation. Neuroimaging confirmed the presence of a Spetzler-Martin grade 2 AVM in the right frontal lobe. Due to the recent liver transplantation, treatment was deferred at the time of initial diagnosis and the patient was observed for a course of 1 year. Follow-up imaging 1 year later showed resolution of the AVM, confirmed by a catheter angiogram.Spontaneous resolution of cerebral AVMs is a rare event. Treatment of chronic liver disease resulted in the normalization of angiogenic factors that likely led to AVM resolution. This case provides valuable insight into the vital role of angiogenesis in the natural history of AVMs.

Introduction Teratomas of the head and neck region are rare lesions, representing just 5% of all congenital teratomas. Usually found in the pineal region orneurohypophysis, teratomas are uncommonly located in the posterior occiput. Case presentation Herein, we present a case of a female neonate born at 37-week gestation with hydrocephalus, an occipital scalp lesion, and several craniofacial abnormalities consistent with a diagnosis of coloboma, heart defect, atresia choanae, retarded growth, genital abnormality, and ear abnormality (CHARGE) syndrome. The occipital scalp lesion was initially thought to be an encephalocele. On day of life 3, the neonate was taken to the operating room for placement of a ventriculoperitoneal shunt and repair of the occipital lesion. Intra-operatively, the lesion resembled a dural-based meningocele; however, during histologic evaluation, it was found to contain tissue derived from all three germ layers and thus, it was determined to be more consistent with a teratoma. Conclusion We hypothesize that a germline mutation in CHD7 or other similar regulatory gene causative of CHARGE syndrome and craniofacial developmental abnormalities may have contributed to the unusual location of the teratoma in this case.

Background Optimal management of third ventricular colloid cysts remains debated. While microsurgery offers greater resection rates and lower recurrences, endoscopy offers a perceived less invasive option. Objective To describe the evolution of our practice to favor microsurgery and determine the optimal management of recurrent colloid cysts. Methods Any patient having undergone surgery for a colloid cyst by the senior author was identified and included in the study cohort. Clinical, radiographic, and operative records were reviewed, with attention paid to those patients requiring recurrent surgery. Results Thirty-three patients were treated for intracranial colloid cysts between 1995 and 2017. Two patients had initial surgical treatment at an outside institution prior to presentation at our institution. Microsurgery was used in 15/31 initial cases, endoscopy in 13 cases, and ventriculoperitoneal shunting in 3 cases. Between 1995 and 2005, 89% of colloid cysts (8/9 cases) were resected endoscopically, whereas 74% of colloid cysts (14/19 cases) were resected by microsurgery after 2005. Of the 13 patients treated endoscopically, 6 (46%) required surgery for recurrent cysts. Incomplete cyst wall resection at the initial operation increased the recurrence rate to 55%. There were no recurrences in the microsurgery cohort. Conclusion Surgical resection of recurrent colloid cysts should focus on complete removal of the cyst wall to minimize the chance of recurrence. Microsurgery has been shown to provide the highest success rates for cyst wall resection and lowest rates of recurrence and is therefore recommended for patients undergoing surgery for primary and recurrent colloid cysts.

BACKGROUND Odontoidectomy is a challenging yet effective operation for decompression of non-neoplastic craniovertebral junction disease. Though both the endoscopic endonasal approach (EEA) and the transoral approach (TOA) have been discussed in the literature, there remain few direct comparisons between the techniques. OBJECTIVE To evaluate the perioperative outcomes of EEA vs TOA odontoidectomy. METHODS A retrospective review of all cases undergoing odontoidectomy by either the EEA or TOA was performed. Attention was paid to the need for prolonged nutritional support, prolonged respiratory support, and hospitalization times. RESULTS During the study period between 2000 and 2018, 25 patients underwent odontoid process resection (18 TOA and 7 EEA). The most common indication for surgery was basilar invagination. Hospital length of stay, intensive care unit length of stay, and intubation days were all significantly shorter in the EEA group compared to the TOA group (P < .01, P = .01, P < .01, respectively). Prolonged nutritional support in the form of a gastrostomy tube was required in 5 patients and tracheostomy was required in 4 patients; all of these underwent odontoidectomy by the TOA. There was no statistical difference in neurological outcomes between the EEA and TOA groups (P = .17). CONCLUSION Odontoidectomy can be performed safely through both the EEA and TOA. The results of this study suggest the EEA has shorter hospitalizations and a lower probability of requiring prolonged nutritional support. These advantages are likely the results of decreased oropharyngeal mucosa disruption as compared to the TOA.

Cerebral bypass is a valuable surgical technique in well-selected patient populations. Updated clinical guidelines and improved surgical techniques warrant a contemporary reevaluation of the complications and patency to inform clinical practice and enhance postoperative patient care.To assess the complication rates and postoperative graft patency for the 3 most common indications for bypass surgery: moyamoya disease, intracranial atherosclerosis, and intracranial aneurysms.Perioperative notes of 175 consecutive bypass patients at a single institution were retrospectively identified to evaluate the clinical course and complications of surgery.The rate of total postoperative complications between moyamoya disease (9 of 98, 9.2%), intracranial atherosclerotic disease (7 of 57, 12.3%), and intracranial aneurysm (4 of 20, 20%) was not statistically different (P = .33). Immediate postoperative bypass patency was significantly higher in moyamoya disease (90 of 96, 93.8%) and intracranial atherosclerotic disease (48 of 51, 94.1%) than in intracranial aneurysm (13 of 18, 72.2%; P = .02). Intravenous heparin administration during bypass suturing was negatively associated with immediate postoperative patency (87% heparin patency vs 99% no heparin patency; P = .02). Double-barrel bypass trended toward an increased risk of wound healing complications (2 of 13, 15.4%) compared with the single-barrel bypass technique (4 of 156, 2.6%; P = .07).Cerebral bypass surgery remains an excellent surgical treatment for moyamoya disease, intracranial atherosclerosis, and intracranial aneurysms. This study suggests bypass is safer in moyamoya disease and intracranial atherosclerosis. Additional studies to clarify the risk of single-barrel vs double-barrel bypass and intraoperative heparin-stratified complications may be beneficial.

Background Surgical strategy in vestibular schwannomas may require subtotal resection to preserve neurologic function. Residual tumor growth pattern and contrast enhancement in the immediate postresection period remain uncertain. We sought to evaluate changes in the enhancement pattern and volume of vestibular schwannomas after subtotal resection in the immediate postoperative period. Methods Volumetric analysis of tumor size and enhancement patterns of vestibular schwannomas were measured on magnetic resonance imaging (MRI) scans obtained within 3 days of surgery, 3 months after surgery, and 1 year after surgery. Results Nineteen patients were eligible for inclusion in the study (9 male and 10 female) with an average age of 47 years. Contrast enhancement was absent in 6 of 19 (32%) of cases on the immediate postresection MRI with return of expected enhancement on subsequent studies. Volumetric analysis identified that tumors decreased in size by an average of 35% in the first 3 months (P = 0.025) after resection and 46% in the first year after resection (P Conclusions Vestibular schwannomas that undergo subtotal resection tend to decrease in size over the first 3 months after resection. Residual tumor volume may fail to enhance on the immediate postresection MRI. Both of these findings could lead surgeons to misinterpret degree of resection after surgery and have implications for clinical decision making and research reporting in the scientific literature for vestibular schwannomas after subtotal resection.

Objectives Initially treating vestibular schwannomas (VSs) with subtotal resection (STR) followed by Gamma Knife radiosurgery (GKRS) for progression of tumor residual is a strategy that balances maximal tumor resection with preservation of neurological function. The effect of timing of GKRS for residual and recurrent VSs remains poorly defined. We developed a simple and practical treatment algorithm for the timing of GKRS after STR of VSs and reviewed our follow-up results to determine outcomes between patients treated with early vs. late GKRS. Patients and methods Patients that underwent STR between 1999 and 2017 for a VS at Tufts Medical Center were identified and included in the study cohort. Patients who received GKRS ≤ 12 months after STR were included in the early intervention group. Patients who received GKRS > 12 months after STR or did not have tumor progression on follow-up thus not requiring GKRS were included in the observation/delayed intervention group. Results STR of VSs was performed on 23 patients. Mean patient age at the time of STR was 53.0 years (range: 20–86.2). The mean follow-up was 4.2 years (range: 1 month-15.5 years). Patients most frequently presented with hearing loss. There were 5 patients (21.7 %) in the early intervention group and 18 (78.3 %) patients in the observation/delayed intervention group. Ten of 23 patients (43.5 %) required GKRS. Thirteen (56.5 %) did not receive GKRS. None of the patients in the early intervention group or the observation/delayed intervention group had changes in House-Brackmann (HB) Grade either after GKRS or at the end of the study period. Conclusions GKRS of residual or recurrent tumor is safe following STR of VS and appears to carry a low risk of worsening facial nerve function when performed for progressive tumor growth.

Surgery within the posterior cranial fossa requires a detailed anatomic understanding of the relevant vascular and neural structures to minimize the risk of inadvertent injury. Dissection near or on vital neural structures must be performed delicately because undue tension can lead to traction injury on the brainstem. Inadvertent loss of a single perforating artery from the vertebrobasilar vasculature can lead to a brainstem infarct. Several studies have identified a low but consistent rate of postoperative brainstem infarction from 0.5% to 0.75% of cases. Vascular complications remain the greatest source of permanent postoperative morbidity after surgery in the posterior fossa. Though these are rare complications, the neurologic deficits they produce can be devastating.

OBJECTIVESurgical resection of sphenoid wing tumors and intraorbital pathology carries the dual goal of appropriately treating the target pathology as well as correcting proptosis. Residual proptosis following surgery can lead to cosmetic and functional disability. The authors sought to quantitatively assess the effect of orbital volume before and after reconstruction to determine the optimal strategy to achieve proptosis correction.METHODSAll surgeries involving orbital wall reconstruction for orbital or intracranial pathology that preoperatively resulted in proptosis between 2007 and 2017 were reviewed. Proptosis was measured by the exophthalmos index (EI): the ratio of the distance of the anterior limit of each globe to a line drawn between the anterior limit of the frontal processes of the zygomas, comparing the pathological eye to the normal eye. Postoperative radiographic measurements were taken at least 60 days after surgery to allow surgical swelling to abate. The orbit contralateral to the pathology was used as an internal control for normal anatomical orbital volume. Cases with preoperative EI < 1.10, orbital exenteration, or enucleation were excluded.RESULTSTwenty-three patients (16 females and 7 males, with a mean age of 43.6 ± 22.8 years) were treated surgically for tumor-associated proptosis. Nineteen patients harbored meningiomas (11 en-plaque; 8 sphenoid wing), and one patient each harbored an orbital schwannoma, glomangioma, arteriovenous malformation, or cavernous hemangioma. Preoperative EI averaged 1.28 ± 0.10 (range 1.12–1.53). Median time to postoperative imaging was 19 months. Postoperatively, the EI decreased to a mean of 1.07 ± 0.09. Greater increases in size of the reconstructed orbit were positively correlated with greater quantitative reductions in proptosis (p < 0.01). Larger volume of soft tissue pathology was also associated with achieving greater proptosis correction (p < 0.01). Residual exophthalmos (defined as EI > 1.10) was present in 8 patients, while reconstruction in 2 patients resulted in clinically asymptomatic enophthalmos (defined as EI < 0.95). Tumor invasion into the superior orbital fissure sinus was associated with residual proptosis (p = 0.04).CONCLUSIONSProptosis associated with intracranial and orbital pathology represents a surgical challenge. The EI is a reliable and quantitative assessment of proptosis. For orbital reconstruction in cases of superior orbital fissure involvement, surgeons should consider rebuilding the orbit at slightly larger than anatomical volume.

Objective Solitary fibrous tumors (SFT) and hemangiopericytomas (HPC) are now classified along a single spectrum of fibroblastic mesenchymal tumors with NAB2–STAT6 fusion. This fusion acts as a driver mutation that constitutively activates EGR1, which is known to be involved in the p16 pathway. Overexpression of p16 is associated with malignancy and worse prognosis in multiple mesenchymal tumors. The authors sought to investigate p16 immunoexpression in association with malignancy and prognosis of SFT/HPC tumors. Design Twenty-three SFT/HPC tumors (central nervous system [CNS]: 12, non CNS: 11) diagnosed at our institution from 2002 to 2016 were assigned into 3 grades. Data from microarray immunohistochemistry for STAT6, synaptophysin, CD56, chromogranin, SST2A, EGR1, Ki67, and p16, grade and survival were analyzed. Results CNS SFT/HPCs tend to be malignant (grade 3; 67 vs. 18%, p = 0.036) and more likely to express synaptophysin (33 vs. 0%, p = 0.035) than non CNS tumors. Overexpression of p16 (immunopositivity ≥ 50% tumor cells) was associated with malignant (grade 3) tumors, and has a sensitivity of 70% (7/10), and a specificity of 77% (10/13), as a predictive marker for malignancy. SFT/HPC patients with low p16 expression demonstrated significantly longer disease-free survival time (median survival > 113 months) than those with high p16 expression (median survival = 30 months, p = 0.045). Conclusions SFT/HPCs in the CNS are more likely to be malignant than the tumors in other sites. High p16 expression is also associated with malignancy and shorter disease-free survival time in SFT/HPC tumors in our study cohort. Clinically, p16 overexpression can be used as predictive marker for malignancy and prognosis and a possible therapeutic target.

The cerebellopontine angle (CPA) is the most common location of posterior fossa tumors. Common pathologic entities in the CPA include vestibular schwannomas, which account for 10% of all primary brain neoplasms, meningiomas, and arachnoid cysts. Surgical approaches to the CPA vary depending on the tumor size, location, and preoperative neurologic function of the patient. The retrosigmoid approach is perhaps the most versatile approach, affording excellent visualization for large tumors and allowing for hearing preservation. Radiosurgery plays an increasing role in the treatment of CPA pathology due to high rates of facial nerve function preservation and tumor growth arrest.

OBJECTIVEPrevious reports have addressed the short-term response of patients with Chiari-related scoliosis (CRS) to suboccipital decompression and duraplasty (SODD); however, the long-term behavior of the curve has not been well defined. The authors undertook a longitudinal study of a cohort of patients who underwent SODD for CRS to determine whether there are factors related to Chiari malformation (CM) that predict long-term scoliotic curve behavior and need for deformity correction.METHODSThe authors retrospectively reviewed cases in which patients underwent SODD for CRS during a 14-year period at a single center. Clinical (age, sex, and associated disorders/syndromes) and radiographic (CM type, tonsillar descent, pBC2 line, clival-axial angle [CXA], syrinx length and level, and initial Cobb angle) information was evaluated to identify associations with the primary outcome: delayed thoracolumbar fusion for progressive scoliosis.RESULTSTwenty-eight patients were identified, but 4 were lost to follow-up and 1 underwent fusion within a year. Among the remaining 23 patients, 11 required fusion surgery at an average of 88.3 ± 15.4 months after SODD, including 7 (30%) who needed fusion more than 5 years after SODD. On univariate analysis, a lower CXA (131.5° ± 4.8° vs 146.5° ± 4.6°, p = 0.034), pBC2 > 9 mm (64% vs 25%, p = 0.06), and higher initial Cobb angle (35.1° ± 3.6° vs 22.8° ± 4.0°, p = 0.035) were associated with the need for thoracolumbar fusion. Multivariable modeling revealed that lower CXA was independently associated with a need for delayed thoracolumbar fusion (OR 1.12, p = 0.0128).CONCLUSIONSThis investigation demonstrates the long-term outcome and natural history of CRS after SODD. The durability of the effect of SODD on CRS and curve behavior is poor, with late curve progression occurring in 30% of patients. Factors associated with CRS progression include an initial pBC2 > 9 mm, lower CXA, and higher Cobb angle. Lower CXA was an independent predictor of delayed thoracolumbar fusion. Further study is necessary on a larger cohort of patients to fully elucidate this relationship.

Object The benefits of treating intracranial aneurysms in the region of the anterior visual pathways are well understood. However, the adverse effects of endovascular stenting across the ophthalmic artery have received little attention. The authors reviewed their experience with patients who had stents deployed across the ophthalmic artery origin. Methods Patients' medical charts and imaging studies were reviewed to identify all patients with a non–flow diverting stent deployed over the ophthalmic artery origin for the treatment of intracranial aneurysms. All patients with neuro-ophthalmic complaints were referred for formal ophthalmological evaluation. Results A total of 104 consecutive patients with 106 aneurysms were identified to meet criteria for inclusion in the study cohort. Preoperatively, 30 patients (29%) described headache symptoms and 32 patients (31%) reported visual complaints. Of the patients with preoperative headaches, 15 (54%) of 28 patients for whom follow-up was available experienced improvement in their symptoms. Of the patients with preoperative visual complaints, improvement was noted in 11 (41%) of the 27 patients for whom follow-up was available, 9 (33%) of 27 patients reported no change in visual symptoms, and 7 (26%) of 27 patients reported progression of symptoms. Visual field defects developing posttreatment were noted to occur in 8 (7.7%) of 104 patients: 3 with immediate postoperative retinal infarcts, 1 with perioperative hemianopia that resolved by the time of discharge, 1 with a subjective visual field defect, 1 with subjective migratory visual field defects, and 2 with nonspecific visual symptoms. Compressive symptoms from aneurysm mass effect were noted in 6 patients preoperatively, with 4 of those patients experiencing persistent worsening, resolution in 1 case, and no change in 1 case. One patient developed a novel cranial nerve palsy from mass effect in the immediate postoperative period. Conclusions Deployment of stents across the ophthalmic artery origin for the treatment of intracranial aneurysms appears to be relatively safe with regard to visual outcomes. Neuro-ophthalmic complaint resolution rates were comparable to endovascular procedures that do not employ stents, with headache resolution rates comparable to coil-only aneurysm obliteration and low rates of retinal ischemic events. For patients presenting with mass effect, stent-assisted coiling appears to be less effective than microsurgery with decompression for relief of compressive symptoms.

While high-resolution cone-beam computational tomographic (CBCT) angiography has gained use in intracranial vascular imaging, digital subtraction angiography (DSA) and 3-dimensional-rotational angiography (3D-RA) remain the preferred acquisition modalities for intracranial aneurysm imaging. This case report highlights the utility of the greater spatial resolution afforded by CBCT for cerebral aneurysm imaging. A 54-year-old man presenting with subarachnoid hemorrhage was confirmed to harbor a ruptured anterior communicating artery aneurysm by conventional angiography. Due to varying contrast opacification captured by different acquisition methods, dramatic aneurysm shape difference was observed between 2- and 3-dimensional-angiographic and CBCT models. The greater resolution of CBCT revealed in an unequivocal fashion the exact site of rupture on the aneurysm dome, visualized as a discrete irregular and elongated bleb that was not seen on either 3D-RA or DSA. High-resolution CBCT visualized the shape of the target aneurysm in greater detail than the more conventional 2D-DSA and 3D-RA, enabling more precise computational fluid dynamics (CFD) simulations. Given that aneurysms most likely change shape either prior to rupture or upon rupture, future studies evaluating fluid dynamics using computer reconstructions should be cognizant of the differences in resolution provided by various imaging modalities.

Object Flow-diverting stents offer a novel treatment approach to intracranial aneurysms. Data regarding the incidence of acute procedure-related thromboembolic complications following deployment of the Pipeline Embolization Device (PED) remain scant. The authors sought to determine the rate of embolic events in a bid to identify potential risk factors and assess the role of platelet inhibition. Methods Data in all patients receiving a PED for treatment of an intracranial aneurysm were prospectively maintained in a database. Diffusion-weighted 3-T MRI was performed within 24 hours of PED deployment. The incident rate of procedural embolism was established, and univariate analysis was then performed to determine any associations of embolic events with measured variables. The degree of platelet inhibition in response to aspirin and clopidogrel was evaluated by challenging the platelet samples with arachidonic acid and adenosine diphosphate, respectively, and then performing formal light transmission platelet aggregometry. Results Twenty-three patients with 26 aneurysms were eligible for inclusion in the study. Thirty-one PEDs were deployed in 25 procedures. All ischemic lesions detected on diffusion-weighted 3-T MRI were identified as embolic based on their location and distribution, with none appearing to be due to perforator artery occlusion. Procedural embolic events were found in the target parent vessel territory in 13 (52%) of 25 procedures, with no patients harboring lesions contralateral to the deployed PED. The number of embolic events per procedure ranged from 3 to 16, with a mean of 5.4. There was no significant difference between cases with and without procedural embolism in platelet inhibition by aspirin (mean 15% vs 12% residual activation; p = 0.28), platelet inhibition by clopidogrel (mean 41% vs 41% residual activation; p = 0.98), or intraprocedural heparin-induced anticoagulation (mean activated clotting time 235 seconds vs 237 seconds; p = 0.81). By multivariate analysis, the authors identified larger aneurysm size (p = 0.03) as the single variable significantly associated with procedural embolism. There was no significant relationship between aneurysm size and the number of embolic events (p = 0.32) or the total burden of the embolism lesion area (p = 0.53). Conclusions Acute embolism following use of the PED for treatment of intracranial aneurysms is more common than hypothesized. The only identifiable risk factor for embolism appears to be greater aneurysm size, perhaps indicating significant disturbed flow across the aneurysm neck with ingress and egress through the PED struts. The strength of antiplatelet therapy, as measured by residual platelet aggregation, did not appear to be associated with cases of procedural embolism. Further work is needed to determine the implications of these findings and whether anticoagulation regimens can be altered to lower the rate of complications following PED deployment.

Background Detection of procedural thromboembolism by diffusion-weighted magnetic resonance imaging (MR-DWI+) can help identify and mitigate endovascular risk factors. Data remain scant on procedural MR-DWI+ following the use of the Neuroform open-cell design stent in aneurysm embolization. Objective We sought to evaluate the incidence of MR-DWI+ in Neuroform simple and multi-stent construct stenting for intracranial aneurysms in an attempt to delineate baseline risk and identify possible associated procedural factors. Methods Seventy-six patients receiving 97 Neuroform stents in the treatment of intracranial aneurysm were identified from a prospective database and eligible for inclusion in the study. Diffusion-weighted magnetic resonance imaging (MR-DWI) was obtained in all patients within 48 hours of the procedure and reviewed for the presence of MR-DWI+ with patient records reviewed for analysis of factors predisposing to these lesions. Results Patients were treated with single-stent Neuroform constructs in 57 cases (73%) and multi-stent Neuroform constructs in 21 cases (27%). Y-stent technique was used in 16 cases. MR-DWI+ was identified in 7 of 78 cases (9.0%), with MR-DWI+ in 0 of 10 subarachnoid hemorrhage cases. No MR-DWI lesions led to a permanent neurological deficit at discharge. There was no MR-DWI+ in patients treated with Y-stenting or multi-stent Neuroform constructs. The only factor associated with ipsilateral MR-DWI+ was target aneurysm location on an arterial sidewall over bifurcation (P = .01). Conclusion The Neuroform stent carries a very low risk of MR-DWI+ compared with its closed-cell design counterpart. Subarachnoid hemorrhage and deployment of multiple stents in the same anatomical region in configurations such as the Y-stent construct did not increase the risk of acute procedural thromboembolism.

Object Incomplete stent apposition of the closed cell–design Enterprise stent following stent-mediated coil embolization of intracranial aneurysms has been associated with increased risk of periprocedural thromboembolic events. In this study, the authors seek to determine the natural history of incomplete stent apposition and evaluate the clinical implications of the phenomenon. Methods Since January 2009, all patients receiving Enterprise stents in the treatment of intracranial aneurysms at the authors' institution have undergone serial 3-T MRI with incomplete stent apposition identified by the crescent sign on multiplanar reconstructions of MR angiograms. Magnetic resonance images and MR angiograms obtained at 3, 9, and 18 months after stent-assisted coil embolization were analyzed along with admission and follow-up clinical medical records. These records were evaluated for any radiographic and clinical, transient or permanent ischemic neurological events. Results Fifty patients receiving Enterprise stents were eligible for inclusion and analysis in the study. Incomplete stent apposition was identified in postoperative imaging studies in 22 (44%) of 50 patients, with 19 (86%) of 22 crescent signs persisting and 3 (14%) of 22 crescent signs resolving on subsequent serial imaging. Delayed ischemic events occurred in 8 (16%) of 50 cases, and all cases involved patients with incomplete stent apposition. The events were transient ischemic attacks (TIAs) in 5 cases, asymptomatic radiographic strokes in 2 cases, and symptomatic strokes and TIAs in the final case. There were no delayed ischemic events in patients who did not have incomplete stent apposition. Only 1 of the delayed ischemic events (2%) was permanent and symptomatic. The postoperative presence of a crescent sign and persistence of the crescent sign were both significantly associated with delayed ischemic events (p < 0.001 and p = 0.002, respectively). Conclusions Incomplete stent apposition is a temporally persistent phenomenon, which resolves spontaneously in only a small minority of cases and appears to be a risk factor for delayed ischemic events. Although further follow-up is needed, these results suggest that longer duration of antiplatelet therapy and clinical follow-up may be warranted in cases of recognized incomplete stent apposition.

Object Few data are available on how closely stents appose the luminal vessel wall in stent-mediated coil embolization of intracranial aneurysms and on the effect of incomplete stent apposition on procedural thromboembolic complications. Methods Postprocedural 3-T MR diffusion-weighted imaging and time-of-flight angiography were obtained in 58 patients undergoing stent-mediated coil embolization of aneurysms using the Enterprise closed-cell and Neuroform open-cell self-expanding intracranial microstents. Results A distinctive semilunar signal pattern, identified using 3-T MR angiography, represented flow outside the confines of the stent struts in patients in whom Enterprise but not Neuroform devices were used. This pattern, designated as the crescent sign, was confirmed to correspond to incomplete stent apposition by use of high-resolution angiographic flat-panel CT scanning revealing flow ingress into and egress out of the isolated luminal wedge. The presence of the crescent sign was seen in 18 of 33 Enterprise-treated but in 0 of 25 Neuroform-treated cases, and was more likely in stents delivered in the tortuous internal carotid artery (p = 0.034). The crescent sign was strongly predictive of ipsilateral postprocedural lesions seen on diffusion-weighted imaging in the entire population (OR 18, 95% CI 4.33–74.8; p < 0.0001). In the Enterprise stent subset, ipsilateral lesions were detected on diffusion-weighted imaging in 15 (45%) of 33 cases; the crescent sign was seen in 12 (80%) of 15 patients with ipsilateral lesions on diffusion-weighted imaging, but in only 6 of 18 patients without lesions (OR 8, 95% CI 1.61–39.6; p = 0.006). Conclusions Incomplete stent apposition is detectable on 3-T MR angiography as a crescent sign, and was found to be highly prevalent in Enterprise closed-cell design stents used to assist coil embolization of aneurysms. Incomplete stent apposition was also associated with periprocedural ipsilateral hyperintense lesions on diffusion-weighted imaging. These results identify an association between incomplete stent apposition and thromboembolic complications in stent-mediated coil embolization of intracranial aneurysms.

A 71-year-old female patient was referred in 2013 for evaluation of an asymptomatic nonsecreting pituitary adenoma. The adenoma, measuring 13 mm in height by 10 mm in width, was discovered incidentally on imaging in 2012. Biochemical testing demonstrated a nonfunctioning adenoma. Given the relatively small lesion size and the lack of symptoms, observation was preferred over surgical intervention. The patient was monitored with routine MRI, which until 2016 demonstrated minimal growth. In early 2016, the patient developed recurrence of metastatic breast cancer and was treated with palbociclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor. This inhibitor acts on a pathway believed to be involved in pituitary adenoma tumorigenesis. One year after starting palbociclib, routine imaging demonstrated significant regression of her pituitary adenoma. The authors hypothesize that inhibition of the CDK4/6 pathway by palbociclib contributed to adenoma regression in this patient, and that palbociclib may represent a possible adjuvant therapy for the treatment of nonfunctioning pituitary adenomas.

Background and Purpose— Flow diversion using the Pipeline Embolization Device is reported as a safe treatment of aneurysms. Complete aneurysm occlusion, however, occurs in a delayed fashion with initial persistent filling of the aneurysm dome. We hypothesized that this transflow across metallic struts may be associated with thromboembolic events. Methods— Forty-one consecutive patients undergoing aneurysm treatment with the Pipeline Embolization Device and a comparison group of 78 Neuroform stent-mediated embolizations were studied. Patients’ charts, procedure notes, platelet function, and anticoagulation state were analyzed. Serial magnetic resonance images were assessed for the presence of newly occurring diffusion-weighted imaging and fluid-attenuated inversion recovery (FLAIR) lesions at multiple postprocedure time ranges (average days post procedure [Pipeline Embolization Device/Neuroform]: T1=1, T2=73/107, T3=174, T4=277/335, and T5=409). In addition, diffusion-weighted imaging or FLAIR burden was estimated by lesional diameter summation. Results— Pipeline patients were more likely to have new ipsilateral FLAIR lesions at all time points studied (30.6% versus 7.2% of patients at T=2 and 34.5% versus 6.2% at T=4). The mean FLAIR burden was significantly increased for Pipeline patients (10.1 versus 0.7 mm at T=2 and 8.8 versus 1.9 mm at T=4). Overall 34% (14/41) of Pipeline patients experienced a new FLAIR lesion at anytime when compared with 10% (8/78) of Neuroform stent-coil patients. Postprocedural diffusion-weighted imaging did not predict future FLAIR lesions suggesting a nonprocedural cause. Conclusions— The Pipeline Embolization Device is associated with increased rate of de novo FLAIR lesions occurring in a delayed fashion and distinct from perioperative diffusion-weighted imaging lesions. The cause and clinical effect of these lesions are unknown and suggest the need for prudent follow-up and evaluation.

Introduction Cervical spinal cord herniation is a rare clinical entity. Reported after previous intradural surgery or surgery complicated by durotomy, patients return several months to years later with symptoms of worsening myelopathy. Herein is presented a case of a 51-year-old female patient with spinal cord herniation in the cervical spine after kyphosis deformity correction. Case Description A 51-year old female patient presented to the neurosurgery clinic with worsening cervical myelopathy due to cervical spinal cord tethering and adhesions from previous intradural surgery for Chiari malformation. Conservative treatment initially was recommended but ultimately unsuccessful, as her neurologic function continued to deteriorate. Follow-up imaging demonstrated progressive cervical kyphotic deformity with stability of the tethered spinal cord. The patient underwent cervical deformity correction to reduce tension on the spinal cord, after which her neurologic symptoms stabilized and began to improve with physical therapy. Four months after surgery, she returned to clinic with recurrence of cervical myelopathy. Repeat imaging demonstrated herniation of the cervical spinal cord through a dorsal defect, and the patient was treated successfully with a wide cervical duraplasty to recreate an intact thecal sac. Conclusions The inability of the spinal cord to compensate for changes in spinal alignment in cases of tethering makes it susceptible to increased pressure and tension at the point of tethering. Caution is urged when attempting deformity correction in the presence of spinal cord tethering, which may limit the capacity of the spinal cord and surrounding tissue to compensate for alterations in spinal alignment.

Wide-necked bifurcation aneurysms often require the use of the technically complex Y-stent technique, which has recently been shown to narrow bifurcation angle in a hemodynamically favorable manner. We sought to evaluate the single center efficacy and safety of Y-stent supported aneurysm coil embolization. All patients undergoing Y-stent supported coiling between September 2006 and December 2012 were identified; records were analyzed for procedural results and complications, with follow-up evaluated for occlusion rate and neurological adverse events. Twenty consecutive patients underwent technically successful Y-stent supported coiling, with complete aneurysm occlusion achieved in 19/20 cases (95%). There were no peri-procedural clinically evident neurological complications following Y-stenting. Clinical follow-up was available for a mean of 20.0months and radiographic follow-up was available for a mean of 18.5months. During the follow-up period, three patients (15%) required re-treatment with through-stent coiling for recanalization. At latest follow-up, Raymond grade I occlusion was achieved in 16 patients (80%), Raymond grade II occlusion achieved in four patients (20%) and Raymond grade III occlusion in zero patients. Y-stenting for complex intracranial aneurysms appears effective in achieving durable aneurysm occlusion with an acceptable safety profile. Though the procedure is technically more complex than single-stent procedures, the Y-stent configuration should be considered when single-stent supported coiling is not feasible or sufficient.

The flow-diverting Pipeline Embolization Device (PED; ev3 Neurovascular, Irvine, CA, USA) provides proven flow diversion for intracranial wide-necked and fusiform aneurysms. The tendency of the PED to migrate and foreshorten when its size is mismatched with the parent vessel makes its use more difficult for cervical carotid pseudoaneurysms, as the parent vessel regains its luminal diameter during the healing phase, and because of its mobility during head movement. We present a novel technique of using a Solitaire detachable stent (ev3 Neurovascular) to anchor PED constructs to mitigate these shortcomings. Two patients with shallow and broad-necked cervical carotid pseudoaneurysms with underlying parent vessel stenosis deemed poor candidates for conventional stent-supported coiling were treated using tandem overlapping PED centered over the neck of the pseudoaneurysm and a Solitaire concentric anchor was deployed to overlap distally and proximally. As predicted, both patients revealed carotid luminal gain after aneurysm thrombosis with attendant migration (3.8 and 2.8 mm) and expansion of the PED construct (14% and 7.8%) which remained constrained within the Solitaire anchoring device with persistent luminal patency and no evidence of endoleak at follow-up (3 and 5 months). The use of a concentric anchoring stent can mitigate the inherent tendency of the braided flow-diverting PED to migrate and foreshorten as the target vessel heals upon pseudoaneurysm thrombosis. This novel technique opens the possibility of using PED to treat shallow or fusiform lesions in mobile cervical arteries previously relegated to stent-supported coiling or surgical reconstruction.

Flow-diverting stents offer a novel treatment approach to intracranial aneurysms. Data regarding the incidence of acute procedure-related thromboembolic complications following deployment of the Pipeline Embolization Device (PED) remain scant. The authors sought to determine the rate of embolic events in a bid to identify potential risk factors and assess the role of platelet inhibition.Data in all patients receiving a PED for treatment of an intracranial aneurysm were prospectively maintained in a database. Diffusion-weighted 3-T MRI was performed within 24 hours of PED deployment. The incident rate of procedural embolism was established, and univariate analysis was then performed to determine any associations of embolic events with measured variables. The degree of platelet inhibition in response to aspirin and clopidogrel was evaluated by challenging the platelet samples with arachidonic acid and adenosine diphosphate, respectively, and then performing formal light transmission platelet aggregometry.Twenty-three patients with 26 aneurysms were eligible for inclusion in the study. Thirty-one PEDs were deployed in 25 procedures. All ischemic lesions detected on diffusion-weighted 3-T MRI were identified as embolic based on their location and distribution, with none appearing to be due to perforator artery occlusion. Procedural embolic events were found in the target parent vessel territory in 13 (52%) of 25 procedures, with no patients harboring lesions contralateral to the deployed PED. The number of embolic events per procedure ranged from 3 to 16, with a mean of 5.4. There was no significant difference between cases with and without procedural embolism in platelet inhibition by aspirin (mean 15% vs 12% residual activation; p = 0.28), platelet inhibition by clopidogrel (mean 41% vs 41% residual activation; p = 0.98), or intraprocedural heparin-induced anticoagulation (mean activated clotting time 235 seconds vs 237 seconds; p = 0.81). By multivariate analysis, the authors identified larger aneurysm size (p = 0.03) as the single variable significantly associated with procedural embolism. There was no significant relationship between aneurysm size and the number of embolic events (p = 0.32) or the total burden of the embolism lesion area (p = 0.53).Acute embolism following use of the PED for treatment of intracranial aneurysms is more common than hypothesized. The only identifiable risk factor for embolism appears to be greater aneurysm size, perhaps indicating significant disturbed flow across the aneurysm neck with ingress and egress through the PED struts. The strength of antiplatelet therapy, as measured by residual platelet aggregation, did not appear to be associated with cases of procedural embolism. Further work is needed to determine the implications of these findings and whether anticoagulation regimens can be altered to lower the rate of complications following PED deployment.

While high-resolution cone-beam computational tomographic (CBCT) angiography has gained use in intracranial vascular imaging, digital subtraction angiography (DSA) and 3-dimensional-rotational angiography (3D-RA) remain the preferred acquisition modalities for intracranial aneurysm imaging. This case report highlights the utility of the greater spatial resolution afforded by CBCT for cerebral aneurysm imaging. A 54-year-old man presenting with subarachnoid hemorrhage was confirmed to harbor a ruptured anterior communicating artery aneurysm by conventional angiography. Due to varying contrast opacification captured by different acquisition methods, dramatic aneurysm shape difference was observed between 2- and 3-dimensional-angiographic and CBCT models. The greater resolution of CBCT revealed in an unequivocal fashion the exact site of rupture on the aneurysm dome, visualized as a discrete irregular and elongated bleb that was not seen on either 3D-RA or DSA. High-resolution CBCT visualized the shape of the target aneurysm in greater detail than the more conventional 2D-DSA and 3D-RA, enabling more precise computational fluid dynamics (CFD) simulations. Given that aneurysms most likely change shape either prior to rupture or upon rupture, future studies evaluating fluid dynamics using computer reconstructions should be cognizant of the differences in resolution provided by various imaging modalities.

Background The Enterprise (EN) vascular reconstruction device is a self-expanding nitinol stent used as adjunctive support in wide-necked aneurysm coiling. We sought to evaluate the effect of deployment technique on how well the EN stent conforms to the vessel wall around a curve. Methods A flow model consisting of a 3.5 mm diameter silicone tube forming a 7 mm radius curve was visualized using high-resolution flat-panel CT (FPCT; DynaCT). EN stents (4.5 mm×22 mm) were deployed using three methods: (1) microcatheter pull-back, (2) delivery microwire push and (3) a combination of both methods so as to keep the microcatheter tip centered within the lumen during deployment. FPCT images were visualized using multiplanar reconstruction for evidence of incomplete stent apposition (ISA). Results FPCT revealed a critical role for deployment method in stent–wall apposition as noted by the development of a crescent-shaped gap between the stent and the wall. Specifically, the manufacturer-recommended microcatheter pull-back unsheathing technique (method 1) resulted in outer curve ISA, while the microwire push technique (method 2) led to inner curve ISA. Using method 3 in a dynamic push–pull manner minimized both inner and outer curve ISA. Conclusion The deployment method used to deliver the EN vascular reconstruction device plays a critical role in determining how well its struts appose the vessel wall in vitro. This characteristic must be taken into account when deploying this flexible low-profile stent to avoid ISA in even mildly tortuous anatomy given the possible link between stent malapposition and thromboembolic complications.

BACKGROUND AND PURPOSE: Flexible microstents, such as the closed-cell EN, have facilitated adjunctive coiling of intracranial aneurysms. Little data are available on the ability of the stent struts to maintain vessel-wall apposition once deployed in the tortuous cerebral vasculature and the prevalence of ISA. The purpose of this study was to evaluate the relationship between geometric features of the parent vessel at the stent deployment site and prevalence of ISA. MATERIALS AND METHODS: Postprocedural 3T-MRA was performed in a cohort of 39 patients undergoing EN stent-assisted intracranial aneurysm coiling. 3T-MRA was analyzed for the presence of ISA and supplemented by angiographic C-arm FPCT (DynaCT). Parent vessel diameter, curvature radius, and stent-subtended arc angle were measured at the site of deployment and analyzed for prediction of ISA in the ICA. RESULTS: 3T-MRA uncovered a unique crescent flow pattern (CS) outside the EN struts, which was confirmed by FPCT to indicate ISA resulting from EN crimping. ISA was detected on 3T-MRA in 19/39 patients (49%). Univariate analysis revealed ISA in the ICA to correlate with a large stent-subtended angle, a small curvature radius, and a large diameter but not stent length or jailing versus a sequential technique. Multivariate analysis identified ISA to correlate with vessel-curvature radius (OR, 253; P = .009), stent-subtended angle (OR, 225; P = .005), and parent vessel diameter (OR, 8.49; P = .044). CONCLUSIONS: In this study, ISA was detectable by 3T-MRA in a significant proportion of patients undergoing EN stent-assisted coiling of ICA aneurysms in a vessel geometry− and stent-deployment location−dependent manner. This characteristic of EN coiling at this potentially tortuous location should be taken into account when selecting an endovascular strategy. CS : crescent sign CS+ : CS present CS− : CS absent 3D-RA : 3D rotational angiography DSA : digital subtraction angiography EN : Enterprise stent or vascular reconstruction device FPCT : flat panel CT ICA : internal carotid artery ISA : incomplete stent apposition MPR : multiplanar reformation OR : odds ratio 3T-MRA : 3T time-of-flight MR angiography

Objective The gold standard for the diagnosis of intracranial atherosclerosis remains catheter based digital subtraction angiography (DSA). A symptomatic hemodynamically non-significant intracranial atherosclerotic lesion is described, whose underlying embologenic characteristics were not detectable by either DSA or three-dimensional rotational angiography (3DRA) but fully realized by C-arm cone beam CT (CBCT) angiography. Clinical presentation A 73-year-old man presented with crescendo transient ischemic attacks consisting of right arm tingling and hand weakness despite long term dual antiplatelet therapy with aspirin and clopidogrel for coronary artery stent. DSA and 3DRA demonstrated a smooth benign appearing left cavernous internal carotid stenosis of Intervention Given the incongruence of the lesion with the patient9s symptoms and lack of response to aggressive medical treatment, a decision was made to obtain higher resolution imaging. CBCT angiography was obtained with injection at two contrast dilutions, which uncovered an underlying ruptured ulcerated calcific plaque with a small dissective component and overlying thrombus. The lesion was treated with anticoagulation followed by balloon mounted stent angioplasty, with symptom resolution and maintained patency at the 1 year follow-up. Conclusion The superior spatial resolution and dynamic range characteristics of CBCT angiography provide added clinical utility in disambiguation of questionable intracranial atherosclerotic lesions which may be missed by conventional planar and rotational angiography. The additional information provided by CBCT angiography could be useful in lesion risk stratification and help refine indications for intracranial stent angioplasty given its recent documented shortcomings vis a vis medical management.

Objective Although intracranial stents have expanded the spectrum of aneurysms amenable to coiling, closed cell design variants can be prone to incomplete stent apposition around tightly curved arterial bends. A case is presented illustrating the technical ramifications of this phenomenon during subsequent treatment. Clinical presentation A 49-year-old woman who had previously undergone Enterprise (closed cell design) stent mediated coiling of a wide necked ophthalmic carotid artery aneurysm was noted to harbor residual central filling on follow-up imaging, and was scheduled for additional embolization. Intervention During retreatment, performed with a second concentrically placed Enterprise and further coil packing using the jailing technique, the proximal portion of the second Enterprise stent failed to expand as expected. C-arm cone beam CT (CBCT) revealed the second stent to have been navigated into and out of the orphaned lumen created by the incompletely apposed first Enterprise stent at the carotid siphon. This stent entanglement resulted in the formation of a trapped proximal double-barrel lumen in the curved segment and resolution to a single barrel lumen in the distal straight segment of the parent vessel facing the aneurysm neck. Conclusion Caution is urged when navigating around curved vessel segments through previously deployed intracranial stents, which may be incompletely apposed to the vessel wall, to avoid deleterious and potentially catastrophic entanglement. CBCT imaging may be helpful in delineating the spatial relationship of previously deployed intracranial stents during subsequent endovascular navigation.