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The impact of coil shape design on angiographic occlusion, packing density and coil mass uniformity in aneurysm embolization: an in vitro study
  1. Manik Mehra1,
  2. Michael C Hurley2,3,
  3. Matthew J Gounis1,
  4. Robert M King1,
  5. Ali Shaibani2,3,
  6. Guilherme Dabus2,3,
  7. Fatimaezzahra E Labdag4,
  8. Elad I Levy5,
  9. Bernard R Bendok2,3
  1. 1New England Center for Stroke Research, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
  2. 2Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
  3. 3Division of Neuroradiology, Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
  4. 4Research and Development, Micrus Endovascular Inc, San Jose, California, USA
  5. 5Department of Neurosurgery, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
  1. Correspondence to Dr M J Gounis, University of Massachusetts, 55 Lake Avenue N, Sa-107R, Worcester, MA 01655, USA; matt.gounis{at}


Objective To investigate the impact of coil design on the distribution of the coil mass in a controlled in vitro experiment. A secondary objective was to study the relationship between angiographic occlusion, packing density and coil mass uniformity.

Methods Seven silicon side wall aneurysm models were embolized in each arm with a different coil design under fluoroscopic guidance. Packing density calculations and scoring of the angiographic occlusion were made. The models were embedded in epoxy and sectioned through the aneurysm neck and the dome. The sections were imaged and processed to derive the fractional surface area of coil material over the coil free area, a quantitative endpoint representing the percentage of the given region of interest consumed by coils. The SD of the surface area fractions is inversely proportional to the uniformity of coil distribution.

Results The novel triangular primary wind design of the Deltapaq achieved a more homogenous distribution of coils within the aneurysm dome compared with the helical and complex microcoil systems (p=0.018). The packing density achieved by the Deltapaq (39.1±1.6%) was significantly higher than the complex (35.2±2.8%) and the helical (32.2±3.3%) coils. Angiographically, aneurysms coiled by the Deltapaq were more likely to obtain a Raymond score of class I.

Conclusion Evaluation of emerging coil technologies with respect to treatment durability may be well served by an assessment of their uniformity of distribution within an aneurysm in addition of the traditional packing density and angiographic occlusion scoring methods.

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  • Funding This work was supported by a research grant from Micrus Endovascular (to BRB and MJG).

  • Competing interests MJG has been a consultant per hour for Micrus Endovascular, Codman Neurovascular and Soteira Inc; receives research support from the National Institutes of Health, Guerbet, Micrus Endovascular Inc, Codman Neurovascular, Boston Scientific, eV3, Philips Healthcare, NeuroVasx Inc and Concentric Medical. FEL was formerly an employee of Micrus Endovascular. EIL receives research grant support, other research support (devices) and honoraria from Boston Scientific and research support from Micrus Endovascular; has an ownership interest in Intratech Medical Ltd and Mynx/Access Closure; serves as a consultant on the board of scientific advisors to Codman Neurovascular Cordis Corporation; serves as a consultant per project and/or per hour for Micrus Endovascular, ev3 and TheraSyn Sensors, Inc; and receives fees for carotid stent training from Abbott Vascular and ev3. BRB receives research support from Microvention, Brain Aneurysm Foundation and the Erika Keeney Foundation.

  • Provenance and peer review Not commissioned; externally peer reviewed.