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Jason M. Davies and Michael T. Lawton


Treatment of cerebrovascular malformations has grown in complexity with the development of multimodal approaches, including microsurgery, endovascular treatments, and radiosurgery. In spite of this changing standard of care, the provision of care continues across a variety of settings. The authors sought to determine the risk of adverse outcome after treatment of patients with vascular malformations in the US. Patient, surgeon, and hospital characteristics, including volume, were tested as potential outcome predictors.


The authors examined data collected between 2000 and 2009 in the Nationwide Inpatient Sample (NIS) database, assessing safety, quality, and cost-effectiveness. They performed multivariate analyses of trends in microsurgical, radiosurgical, and endovascular treatment by hospital and surgeon volume, using death, routine discharge percentage, length of stay (LOS), complications, and hospital charges as end points. They further computed the value of care, which was defined as the ratio of the functional outcome (routine discharge percentage) to cost of care to the payer (hospital charges).


The authors identified 8227 patients with vascular malformations who were treated at US hospitals. Hospitals and surgeons were classified by yearly case volume. Compared with low-volume hospitals (2 or fewer cases/year), high-volume hospitals (16 or more cases/year) had shorter LOS (3 vs 2 days, p = 0.005), higher total charges ($37,374 vs $19,986, p = 0.003), more frequent discharge to home (p < 0.001), and lower mortality rates (0.7% vs 1.16%, p = 0.010). High-volume surgeons (7 or more cases/year) likewise had superior outcomes compared with low-volume surgeons (1 or fewer cases/year), with shorter LOS (2 vs 3 days, p = 0.03), more frequent discharge to home (p < 0.001), and lower mortality rates (0.7% vs 1.10%, p = 0.005). Underlying these outcomes, the rates of intervention for surgery, angiography, embolization, and radiosurgery were likewise significantly different in high- versus low-volume practices.

Based on these results the authors modeled how outcomes might change if care were consolidated at designated centers of excellence (COEs), and found that on an annual basis, care at high-volume hospital COEs would result in 18.5 fewer deaths, 1252.1 fewer hospital days, 182.7 more discharges home without additional services, 48.5 fewer medical complications, and 117.4 fewer perioperative complications. Surgeon-level rates for high-volume COEs demonstrated an even larger benefit over current standards, with 27.4 fewer deaths, 10,713.7 fewer hospital days, a $51.6-million reduction in charges, 370.9 additional routine discharges, and reduced complications in all categories (27.8 fewer surgical, 198.0 fewer medical, and 32.1 fewer perioperative) compared with care at non-COEs.


For patients with vascular malformations who were treated in the US between 2000 and 2009, treatment performed at high-volume centers was associated with significantly lower morbidity and, for high-volume surgeons, with lower mortality rates. These data suggest that treatment by high-volume institutions and surgeons will yield superior outcomes and superior value. The authors therefore advocate the creation of care paradigms that triage patients to high-volume institutions and surgeons, which can serve as cerebrovascular COEs.

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Jason M. Davies and Michael T. Lawton

The “picket fence” clipping technique is a method for clipping large aneurysms when conventional clipping across the neck is not feasible, either due to complex anatomy, atherosclerosis, calcification, or compromise of branch origins. This has also been described as a dome fenestration tube. Parallel straight clips, simple and/or fenestrated, are stacked vertically from dome to neck with the tips reconstructing the neck. In this video, the “picket fence” clipping technique is demonstrated on a large middle cerebral artery (MCA) aneurysm. A total of 14 clips reconstructed the neck, completely occluding the aneurysm and preserving outflow in all branch vessels.

The video can be found here:

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Jason M. Davies, Vijay Yanamadala and Michael T. Lawton


The development of multimodality approaches for the treatment of cerebral arteriovenous malformations (AVMs), including microsurgery, endovascular therapy, and radiosurgery, has shifted modern treatment paradigms in the last 10 years. This study examines these changes in detail from a nationwide perspective.


The authors examined data from 2001 to 2009 in the Nationwide Inpatient Sample (NIS) database, and they assessed the safety, quality, and cost-effectiveness, including the total number of discharges, discharge proportion, length of stay, and hospital charges. The authors also examined patient demographics (including age, sex, income level, and insurance), hemorrhage status at presentation, and trends in open surgical and endovascular treatment.


A total of 33,997 inpatient admissions for patients with a primary diagnosis of intracranial AVM were identified, with a mean of 4191 patients admitted annually. The mean hospital charges increased 2-fold over the study period without significant differences in outcomes. There were substantial differences between surgical, endovascular, radiosurgical, and multimodality treatments. The proportion of AVMs treated microsurgically remained stable over this period, while the proportion treated endovascularly dramatically increased in size, and the data demonstrate important patient-level distinctions among groups. Outcomes and complication profiles were significantly different between treatment modalities and were impacted by age and hemorrhage status.


Charges associated with treatment of cerebral AVMs to the payer and society have increased dramatically over the first decade of the 21st century without clear improvements in quality parameters. However, analysis of the 3 primary treatment modalities has demonstrated differences and warrants further investigation to understand which patient population would benefit maximally from each. Unfortunately, with only imprecise measurements of quality in health care delivery, it remains imperative to develop national databases in which parameters, such as survival, functional outcomes, quality of life, and complication rates, can be assessed to examine the value of care delivered in a more meaningful way. Demonstrating an ever-increasing value of delivered health care will be imperative in our evolving health care system.