Aneurysmal subarachnoid hemorrhage during pregnancy: a comprehensive and systematic review of the literature.

Aneurysmal subarachnoid hemorrhage (aSAH) is an emergent condition requiring rapid intervention and prolonged monitoring. There are few recommendations regarding the management of aSAH in pregnancy. We identified all available literature and compiled management decisions as well as reported outcomes through a systematic literature review without meta-analysis to provide recommendations for management of aSAH during pregnancy. We included a total of 23 articles containing 54 cases of pregnancy-related aSAH in our review. From these reports and other literature, we evaluated information on aSAH pathophysiology, diagnosis, and management with respect to pregnancy. Early transfer to an appropriate facility with neurocritical care, a high-risk obstetric service, and a neurosurgery team available is crucial for the management of aSAH in pregnancy. Intensive monitoring and a multidisciplinary approach remain fundamental to ensure maternal and fetal health.

Transvenous embolization of bilateral indirect carotid-cavernous fistulas via a unilateral transorbital approach.

A 73-year-old man with a complex ophthalmologic history presented with several weeks of worsening diplopia, visual acuity, and proptosis bilaterally. Cerebral angiography demonstrated bilateral indirect Barrow type B carotid-cavernous fistulas (CCFs). Transarterial embolization was not attempted due to small arterial diameter and risk of stroke. Multiple attempts were made to access the fistula via a transfemoral venous approach and were unsuccessful. A transorbital puncture was performed, which allowed access to both cavernous sinuses via a unilateral approach. After embolization with Onyx, there was no residual fistula. The patient had a left-sided retrobulbar hematoma from the access. Right eye vision improved postoperatively.

International multicentre validation of the arteriovenous malformation-related intracerebral haemorrhage (AVICH) score.

OBJECTIVE: The recently published arteriovenous malformation-related intracerebral haemorrhage (AVICH) score showed better outcome prediction for patients with arteriovenous malformation (AVM)-related intracerebral haemorrhage (ICH) than other AVM or ICH scores. Here we present the results of a multicentre, external validation of the AVICH score. METHODS: All participating centres (n=11) provided anonymous data on 325 patients to form the Spetzler-Martin (SM) grade, the supplemented SM (sSM) grade, the ICH score and the AVICH score. Modified Rankin score (mRS) at last follow-up (mean 25.6 months) was dichotomized into favourable (mRS 0-2, n=210) and unfavourable (mRS 3-6;n=115). Univariate and AUROC analyses were performed to validate the AVICH score. RESULTS: Except nidus structure and AVM size, all single parameters forming the SM, sSM, ICH and AVICH score and the scores itself were significantly different between both outcome groups in the univariate analysis. The AVICH score was confirmed to be the highest predictive outcome score with an AUROC of 0.765 compared with 0.705 for the ICH score and 0.682 for the sSM grade. CONCLUSION: The multicentre-validated AVICH score predicts clinical outcome superior to pre-existing scores. We suggest the routine use of this score for future clinical outcome prediction and in clinical research. TRIAL REGISTRATION NUMBER: NCT02920645.

Endovascular treatment of complex dural arteriovenous fistula using the dual-microcatheter technique.

A 71-year-old woman presented with headache and dilated vessels on CTA. Angiography demonstrated a complex dural arteriovenous fistula with retrograde cortical venous hypertension, supplied by branches of internal and external carotids bilaterally into a fistulous pouch paralleling the left transverse and sigmoid sinuses, which was occluded at the jugular bulb. The patient refused treatment and was lost to follow-up, returning with sudden confusion and hemianopsia from left temporo-occipital hemorrhage. Transvenous endovascular embolization was performed using the dual-microcatheter technique with a combination of coiling and Onyx copolymer, completely occluding the sinus and fistula while preserving normal venous drainage. The video can be found here: http://youtu.be/u_4Oc7tSmDM .

Preoperative embolization and microsurgical resection of a cerebellar hemangioblastoma: embolization goals and technical nuances of the approaches. Illustrative case.

BACKGROUND: Resection remains the optimal treatment for hemangioblastomas, highly vascular tumors commonly located in the cerebellum or spinal cord. Preoperative embolization can be used with caution to reduce intraoperative blood loss and promote gross-total resection while reducing neurological morbidity. OBSERVATIONS: The authors report a case of a 44-year-old male who presented with worsening dizziness, gait imbalance, and diplopia. Imaging revealed a large vascular cerebellar mass with brainstem compression and hydrocephalus, concerning for hemangioblastoma. The patient underwent preoperative embolization of the main arterial supply from the right superior cerebellar artery, which devascularized the tumor and reduced the early venous shunting, followed by gross-total resection of the tumor. Preoperative embolization helped to facilitate safe microsurgical resection because this main arterial supply was deep to the planned surgical approach, and the Onyx cast served as a landmark of the dorsal midbrain and remaining arterial supply. This resulted in minimal intraoperative blood loss. At 2-year follow-up, the patient's diplopia and vertigo had resolved, and his gait continues to improve. LESSONS: Despite controversy regarding the use of preoperative embolization for hemangioblastoma resection, the authors emphasize its safety and utility during resection of a large cerebellar hemangioblastoma. Onyx embolization provided benefit in both reducing the tumor blood supply and serving as intraoperative visual guidance.

Open surgical ligation of a thoracic spinal epidural arteriovenous fistula causing thoracic myelopathy: illustrative case.

BACKGROUND: Spinal epidural arteriovenous fistulas (eAVFs) are rare spinal vascular malformations characterized by an abnormal connection from the paraspinal and paravertebral system to the epidural venous plexus. This contrasts with the more frequently seen spinal dural AVF, where the fistula is entirely intradural. Although endovascular repair is commonly performed for spinal eAVF, few cases require open surgical ligation. OBSERVATIONS: The authors present a case of a 74-year-old male with progressive thoracic myelopathy secondary to a spinal eAVF. Thoracic magnetic resonance imaging (MRI) showed intramedullary T2 signal hyperintensity from T8 to T12. Spinal angiography revealed a primary arterial supply from the right T11 segmental artery and minor supply from the left T11 branches with drainage into the ventral epidural space. The patient underwent T11-12 laminectomy and complete right T11-12 facetectomy for ligation of the fistula with T11-L1 fusion. A postoperative spinal angiogram showed resolution of the fistula. Postoperatively, the patient's myelopathy improved, and MRI showed a decrease in T2 cord intensity. LESSONS: Spinal eAVFs are rare lesions that differ from the more commonly seen intradural dural AVF in that the abnormal connection is in the epidural space, and they are often associated with a dilated epidural venous pouch. Treatment involves endovascular, open surgical, or combined approaches.

The Longissimus Capitis Insertion as a Superficial Landmark for the Sigmoid Sinus: An Anatomical Study.

Objective Many external anatomical landmarks have been used for approximating deeper, intracranial structures. Herein, we evaluate the attachment of the longissimus capitis (LC) on the mastoid process as a landmark for the underlying sigmoid sinus. Methods Adult cadavers underwent dissection of the posterior occiput with special attention to the attachment of the LC muscle. Once the periphery of the muscle's tendon of attachment was determined, a burr hole was made in this area and evaluated internally for its relationship to the sigmoid sinus. Results From an intracranial view, burr holes on all sides were over the sigmoid sinus and just slightly lateral to the center of the sinus. The distance from the midline to the medial border of the insertion of the LC had a mean of 63.0 ± 7.2 mm. The width of the tendon of insertion of the LC on the mastoid process had a mean of 17.6 ± 5.7 mm. The length of the tendon insertion of the LC had a mean of 14.7 ± 4.7 mm. The distance from the inferior border of the insertion of the LC to the tip of the mastoid process had a mean of 6.2 ± 4.5 mm. Conclusion To our knowledge, use of the attachment site of the LC on the mastoid process as an external landmark for the underlying sigmoid sinus has not previously been reported. Based on our cadaveric findings, the sigmoid sinus is centered under the attachment of the LC regardless of the width of its tendon.

Mutations of the DNA repair gene PNKP in a patient with microcephaly, seizures, and developmental delay (MCSZ) presenting with a high-grade brain tumor.

Polynucleotide Kinase-Phosphatase (PNKP) is a bifunctional enzyme that possesses both DNA 3'-phosphatase and DNA 5'-kinase activities, which are required for processing termini of single- and double-strand breaks generated by reactive oxygen species (ROS), ionizing radiation and topoisomerase I poisons. Even though PNKP is central to DNA repair, there have been no reports linking PNKP mutations in a Microcephaly, Seizures, and Developmental Delay (MSCZ) patient to cancer. Here, we characterized the biochemical significance of 2 germ-line point mutations in the PNKP gene of a 3-year old male with MSCZ who presented with a high-grade brain tumor (glioblastoma multiforme) within the cerebellum. Functional and biochemical studies demonstrated these PNKP mutations significantly diminished DNA kinase/phosphatase activities, altered its cellular distribution, caused defective repair of DNA single/double stranded breaks, and were associated with a higher propensity for oncogenic transformation. Our findings indicate that specific PNKP mutations may contribute to tumor initiation within susceptible cells in the CNS by limiting DNA damage repair and increasing rates of spontaneous mutations resulting in pediatric glioma associated driver mutations such as ATRX and TP53.

Anatomic Study Quantifying the Relationship Between the Arcuate Eminence and the Root of the Zygoma: Application to Skull Base Surgery.

OBJECTIVE: The aim of this study was to define the structural relationship between the arcuate eminence (AE) and a known fixed external bony landmark, the root of the zygoma (ZR), and to determine its reliability as a consistent guide for guiding surgical approaches. To our knowledge, this is the only anatomic study to quantify the relationship between the AE and ZR. METHODS: Twenty-one dry temporal bones were measured using digital calipers. The distance from the posterior aspect of the ZR to the midpoint of the AE was measured. Additionally, the anteroposterior distance between the ZR and AE and vertical distance between the 2 structures were measured. Student's t-test was used to compare the left and right sides. RESULTS: An AE was found in every specimen. The mean ZR to AE distance was 30.9 mm. On most sides (91%), the ZR was located more inferiorly than the AE with a mean distance of 3 mm between the 2 structures. The mean distance between the AE and ZR was 17 mm. On all sides, the AE was located posterior to the ZR. No significant differences were found between sides. No anatomic variations or pathologic conditions were noted in any of the specimens. CONCLUSIONS: The ZR is an easily identifiable and consistent bony landmark often used by skull base surgeons. In this investigation, we measured the anatomic relationships between the ZR and AE. Such data might assist in planning surgical trajectories and minimizing complications when skull base pathologies are approached.

Anatomical Considerations for Endovascular Intervention for Extracranial Carotid Disease: A Review of the Literature and Recommended Guidelines.

Patient selection for endovascular intervention in extracranial carotid disease is centered on vascular anatomy. We review anatomical considerations for non-traumatic disease and offer guidelines in patient selection and management. We conducted a systematic literature review without meta-analysis for studies involving anatomical considerations in extracranial carotid intervention for non-traumatic disease. Anatomical considerations discussed included aortic arch variants, degree of vessel stenosis, angulation, tortuosity, and anomalous origins, and atheromatous plaque morphology, composition, and location. Available literature suggests that anatomical risks of morbidity are largely secondary to increased procedural times and difficulties in intervention system delivery. We recommend the prioritization of endovascular techniques on an individual basis in cases where accessible systems and surgeon familiarity provide an acceptable likelihood of rapid access and device deployment.

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.

Novel dual-reporter preclinical screen for antiastrocytoma agents identifies cytostatic and cytotoxic compounds.

Astrocytoma/glioblastoma is the most common malignant form of brain cancer and is often unresponsive to current pharmacological therapies and surgical interventions. Despite several potential therapeutic agents against astrocytoma and glioblastoma, there are currently no effective therapies for astrocytoma, creating a great need for the identification of effective antitumor agents. The authors have developed a novel dual-reporter system in Trp53/Nf1-null astrocytoma cells to simultaneously and rapidly assay cell viability and cell cycle progression as evidenced by activity of the human E2F1 promoter in vitro. The dual-reporter high-throughput assay was used to screen experimental therapeutics for activity in Trp53/Nf1-null astrocytoma. Several compounds were identified demonstrating selectivity for astrocytoma over primary astrocytes. The dual-reporter system described here may be a valuable tool for identifying potential antitumor treatments that specifically target astrocytoma.

Endovascular Coil Retrieval Using Dual Synchronous Solitaire Revascularization Devices.

BACKGROUND AND IMPORTANCE: Coil migration is a potential complication of endovascular aneurysm treatment. Dislodged coils into the parent artery require retrieval to prevent thromboembolic complications. A variety of techniques for coil retrieval have been described, including the use of single stentrievers and aspiration catheters. CLINICAL PRESENTATION: The use of 2 stentrievers, as opposed to a single device, was thought to be advantageous in coil removal by the additional point of friction due to the extensive length of coil stretching and earlier failure of a single device. CONCLUSION: In this report, 2 synchronous Solitaire FR Revascularization Devices (Covidien/Medtronic, Dublin, Ireland) were deployed, 1 distal and 1 proximal, to retrieve an inadvertently deployed coil.

Onyx embolization prior to stereotactic radiosurgery for brain arteriovenous malformations: a single-center treatment algorithm.

BACKGROUND: Embolization before stereotactic radiosurgery (SRS) for brain arteriovenous malformations (BAVMs) is controversial. OBJECTIVE: To compare clinical and radiographic outcomes in patients undergoing pre-SRS embolization with ethylene copolymer (Onyx) with outcomes in patients undergoing SRS alone. METHODS: Seventy consecutive patients with BAVMs who underwent SRS were retrospectively reviewed. Univariate and multivariate analyses were performed to assess the factors associated with radiographic obliteration and complication. RESULTS: Forty-one (59%) patients presented without BAVM rupture and 29 (41%) patients presented with rupture. Pre-SRS embolization was used in 20 patients (28.6%; 7 unruptured and 13 ruptured). Twenty-five of 70 (36%) patients sustained a complication from treatment, including 6 (9%) patients with a post-SRS latency period hemorrhage. Ten (14%) patients had persistent neurological deficits after treatment. Functional outcome (as modified Rankin Scale), complication rate, and radiographic obliteration at last follow-up were not significantly different between embolized and non-embolized groups in both unruptured and ruptured BAVMs. For unruptured BAVMs, 3- and 5-year rates of radiographic obliteration were 23% and 73% for non-embolized patients and 20% and 60% for embolized patients, respectively. For ruptured BAVMs, 3- and 5-year rates of radiographic obliteration were 45% and 72% for non-embolized patients and 53% and 82% for embolized patients, respectively. CONCLUSION: Pre-SRS embolization with Onyx was not associated with worse clinical or radiographic outcomes than SRS treatment without embolization. Pre-SRS embolization has a low complication rate and can safely be used to target high-risk BAVM features in carefully selected patients destined for SRS.

Timing of cranioplasty: a 10.75-year single-center analysis of 754 patients.

OBJECTIVE Despite their technical simplicity, cranioplasty procedures carry high reported morbidity rates. The authors here present the largest study to date on complications after cranioplasty, focusing specifically on the relationship between complications and timing of the operation. METHODS The authors retrospectively reviewed all cranioplasty cases performed at Harborview Medical Center over the past 10.75 years. In addition to relevant clinical and demographic characteristics, patient morbidity and mortality data were abstracted from the electronic medical record. Cox proportional-hazards models were used to analyze variables potentially associated with the risk of infection, hydrocephalus, seizure, hematoma, and bone flap resorption. RESULTS Over the course of 10.75 years, 754 cranioplasties were performed at a single institution. Sixty percent of the patients who underwent these cranioplasties were male, and the median follow-up overall was 233 days. The 30-day mortality rate was 0.26% (2 cases, both due to postoperative epidural hematoma). Overall, 24.6% percent of the patients experienced at least 1 complication including infection necessitating explantation of the flap (6.6%), postoperative hydrocephalus requiring a shunt (9.0%), resorption of the flap requiring synthetic cranioplasty (6.3%), seizure (4.1%), postoperative hematoma requiring evacuation (2.3%), and other (1.6%). The rate of infection was significantly higher if the cranioplasty had been performed < 14 days after the initial craniectomy (p = 0.007, Holm-Bonferroni-adjusted p = 0.028). Hydrocephalus was significantly correlated with time to cranioplasty (OR 0.92 per 10-day increase, p < 0.001) and was most common in patients whose cranioplasty had been performed < 90 days after initial craniectomy. New-onset seizure, however, only occurred in patients who had undergone their cranioplasty > 90 days after initial craniectomy. Bone flap resorption was the least likely complication for patients whose cranioplasty had been performed between 15 and 30 days after initial craniectomy. Resorption was also correlated with patient age, with a hazard ratio of 0.67 per increase of 10 years of age (p = 0.001). CONCLUSIONS Cranioplasty performed between 15 and 30 days after initial craniectomy may minimize infection, seizure, and bone flap resorption, whereas waiting > 90 days may minimize hydrocephalus but may increase the risk of seizure.

Dolichoectatic aneurysms of the vertebrobasilar system: clinical and radiographic factors that predict poor outcomes.

OBJECTIVE Fusiform dolichoectatic vertebrobasilar aneurysms are rare, challenging lesions. The natural history of these lesions and medium- and long-term patient outcomes are poorly understood. The authors sought to evaluate patient prognosis after diagnosis of fusiform dolichoectatic vertebrobasilar aneurysms and to identify clinical and radiographic predictors of neurological deterioration. METHODS The authors reviewed multiple, prospectively maintained, single-provider databases at 3 large-volume cerebrovascular centers to obtain data on patients with unruptured, fusiform, basilar artery dolichoectatic aneurysms diagnosed between January 1, 2000, and January 1, 2015. RESULTS A total of 50 patients (33 men, 17 women) were identified; mean clinical follow-up was 50.1 months and mean radiographic follow-up was 32.4 months. At last follow-up, 42% (n = 21) of aneurysms had progressed and 44% (n = 22) of patients had deterioration of their modified Rankin Scale scores. When patients were dichotomized into 2 groups- those who worsened and those who did not-univariate analysis showed 5 variables to be statistically significantly different: sex (p = 0.007), radiographic brainstem compression (p = 0.03), clinical posterior fossa compression (p < 0.001), aneurysmal growth on subsequent imaging (p = 0.001), and surgical therapy (p = 0.006). A binary logistic regression was then created to evaluate these variables. The only variable found to be a statistically significant predictor of clinical worsening was clinical symptoms of posterior fossa compression at presentation (p = 0.01). CONCLUSIONS Fusiform dolichoectatic vertebrobasilar aneurysms carry a poor prognosis, with approximately one-half of the patients deteriorating or experiencing progression of their aneurysm within 5 years. Despite being high risk, intervention-when carefully timed (before neurological decline)-may be beneficial in select patients.

The dual microcatheter technique for transvenous embolization of dural arteriovenous fistulae.

BACKGROUND: Dural arteriovenous fistulae (dAVFs) comprise 10-15% of all intracranial arteriovenous malformations. The goal of surgical or endovascular intervention is complete obliteration of the fistulous connection(s). In cases where dAVF venous drainage is separate from normal cortical drainage, transvenous embolization can provide fast and effective fistula obliteration. OBJECTIVE: To describe a new method of efficient transvenous embolization (the 'dual microcatheter technique') for the treatment of dAVFs. METHODS: Three patients with dAVFs were treated using the dual microcatheter technique for transvenous embolization. Two microcatheters were placed in the distal aspect of the dAVF venous pouch, after which coil embolization reduced fistula flow, and liquid embolic agent injection with reflux into arterial feeders completed the obliteration of the fistula. RESULTS: Lesion grade ranged from Borden-Shucart grades 2 through 3. In all cases, dAVF venous drainage was isolated from the normal cerebral venous drainage. Dual microcatheter transvenous embolization was successful in all patients, with non-target embolization and no new postoperative deficits. At the last follow-up, all three patients were symptom-free without evidence of radiographic recurrence. CONCLUSIONS: The dual microcatheter technique of transvenous dAVF embolization is safe and feasible in cases where dAVF venous outflow is isolated from normal cerebral venous drainage.

Multimodality Management of Spetzler-Martin Grade 3 Brain Arteriovenous Malformations with Subgroup Analysis.

OBJECTIVE: Spetzler-Martin grade 3 (SM3) lesions entail 4 distinct subtypes described based on size, eloquence, and deep venous drainage (3A-3D). The ideal management of each is contentious, and the results of A Randomized Trial of Unruptured Brain AVMs (ARUBA) introduced additional controversy and attention toward management strategies of unruptured brain arteriovenous malformations (bAVMs). METHODS: We retrospectively reviewed 114 patients with treated SM3 bAVMs, including both ruptured and unruptured lesions. Primary outcomes included modified Rankin score at most recent follow-up, angiographic cure, and permanent treatment-related complications (morbidity). Other outcomes included mortality, bAVM recurrence or rebleed, and transient treatment-related complications. We used univariate and multivariate modeling to determine whether any specific features were predictive of outcomes. For unruptured bAVMs, an "ARUBA eligible" subgroup analysis was performed. We also reviewed the literature on management of ruptured and unruptured SM3 bAVMs. RESULTS: Of the 114 identified SM3 bAVMs, 40% were unruptured. Most (43.5%) lesions in the unruptured group were type 3C, whereas most ruptured bAVMs (66.2%) were type 3A. Unruptured lesions were mostly managed with radiosurgery (47.8%) and ruptured ones with preoperative embolization and surgery (36.7%). Surgical intervention was predictive of angiographic cure in multivariate modeling, even after controlling for ≥2 years of follow-up, although associated with a slightly higher rate of morbidity. Focal neurological deficit was the only predictor of a worse (modified Rankin score ≥2) functional outcome in follow-up for unruptured bAVMs. For ruptured bAVMs, superficial and cerebellar locations were predictive of better outcomes in multivariate models, in the absence of a focal neurological deficit at presentation and new after surgery deficit. ARUBA SM3 bAVMs specifically underwent more embolization as a monotherapy and less microsurgical resection than the present series. CONCLUSIONS: In spite of a heterogeneous array of angioarchitectural and anatomic features, SM3 bAVMs can be treated safely and effectively with surgery and radiosurgery either without or with pretreatment embolization. Ruptured lesions are more often type 3A, with smaller nidus, deep brain location, and deep venous drainage. Focal neurological deficit predicts worse clinical outcomes. Contemporary multimodality management of SM3 bAVMs is not adequately represented in the results of ARUBA, likely due to differences in treatment strategies.

Risk of Complications with Simultaneous Cranioplasty and Placement of Ventriculoperitoneal Shunt.

BACKGROUND: The development of hydrocephalus (HCP) necessitating placement of a ventriculoperitoneal shunt (VPS) after decompressive hemicraniectomy occurs at a rate of approximately 5%-15%. The ideal approach for addressing both HCP and a cranial defect remains unclear, and whether concomitant VPS and cranioplasty (CP) increases the risk of complications is uncertain. METHODS: This is a retrospective cohort study of adult patients who underwent CP and VPS placement for any indication at Harborview Medical Center, Seattle between March 2004 and November 2014 with at least 30 days of follow-up. The primary variable of interest was the timing of CP relative to VPS placement. The outcomes of interest were CP- and VPS-related infections, early (within 1 year of placement) VPS obstruction, and a composite of any of these complications in a single patient. RESULTS: The rate of composite outcomes was 15% in the subgroup of patients with simultaneous CP and VPS placement, compared with 29% in the subgroup of patients in whom CP and VPS placement were performed separately, a non-statistically significant difference (P = 0.24). Similarly, there was no statistically significant difference between the subgroups in any of the 3 individual outcomes of interest, which remained after accounting for potential covariates in a multivariate regression model. CONCLUSIONS: In our study population, there was no difference between simultaneous and separate CP and VPS placement with respect to CP infection, VPS infection, and VPS mechanical failure/obstruction. There is equipoise in the current literature regarding the safety of performing these 2 common procedures simultaneously, with studies of similar size and design finding variable degrees of safety of this practice.

Computational fluid dynamics of cerebral aneurysm coiling using high-resolution and high-energy synchrotron X-ray microtomography: comparison with the homogeneous porous medium approach.

BACKGROUND: Computational modeling of intracranial aneurysms provides insights into the influence of hemodynamics on aneurysm growth, rupture, and treatment outcome. Standard modeling of coiled aneurysms simplifies the complex geometry of the coil mass into a homogeneous porous medium that fills the aneurysmal sac. We compare hemodynamics of coiled aneurysms modeled from high-resolution imaging with those from the same aneurysms modeled following the standard technique, in an effort to characterize sources of error from the simplified model. MATERIALS: Physical models of two unruptured aneurysms were created using three-dimensional printing. The models were treated with coil embolization using the same coils as those used in actual patient treatment and then scanned by synchrotron X-ray microtomography to obtain high-resolution imaging of the coil mass. Computational modeling of each aneurysm was performed using patient-specific boundary conditions. The coils were modeled using the simplified porous medium or by incorporating the X-ray imaged coil surface, and the differences in hemodynamic variables were assessed. RESULTS: X-ray microtomographic imaging of coils and incorporation into computational models were successful for both aneurysms. Porous medium calculations of coiled aneurysm hemodynamics overestimated intra-aneurysmal flow, underestimated oscillatory shear index and viscous dissipation, and over- or underpredicted wall shear stress (WSS) and WSS gradient compared with X-ray-based coiled computational fluid dynamics models. CONCLUSIONS: Computational modeling of coiled intracranial aneurysms using the porous medium approach may inaccurately estimate key hemodynamic variables compared with models incorporating high-resolution synchrotron X-ray microtomographic imaging of complex aneurysm coil geometry.