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GEL THE NEC: a prospective registry evaluating the safety, ease of use, and efficacy of the HydroSoft coil as a finishing device
  1. Waleed Brinjikji1,2,
  2. Arun P Amar3,
  3. Josser E Delgado Almandoz4,
  4. Orlando Diaz5,
  5. Pascal Jabbour6,
  6. Ricardo Hanel7,
  7. Ferdinand Hui8,
  8. Michael Kelly9,
  9. Kennith D Layton10,
  10. Jeffrey W Miller11,
  11. Elad Levy12,
  12. Christopher Moran13,
  13. Dae C Suh14,
  14. Henry Woo15,
  15. Robin Sellar16,
  16. Brian Ho17,
  17. Avery Evans18,
  18. David F Kallmes1,2
  1. 1Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
  2. 2Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, USA
  3. 3Department of Neurosurgery, University of Southern California, Los Angeles, California, USA
  4. 4Neuroscience Institute, Abbott Northwestern Hospital, Minneapolis, MN, USA
  5. 5Department of Neurosurgery, Weil Cornel University, New York, New York, USA
  6. 6Department of Neurosurgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA
  7. 7Department of Cerebrovascular and Stroke, Baptist Health System, Jacksonville, Florida, USA
  8. 8Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
  9. 9Department of Neurosurgery, Univeristy of Saskatchewan, Saskatoon, Canada
  10. 10Department of Radiology, Baylor University, Dallas, Texas, USA
  11. 11Department of Neurosurgery, Western Michigan University, Kalamazoo, Michigan, USA
  12. 12Department of Neurosurgery, University at Buffalo, Buffalo, New York, USA
  13. 13Department of Radiology, Washington University School of Medicine, Saint Louis, Missouri, USA
  14. 14Department of Radiology, Asan Medical Center, Seoul, Korea, Republic of
  15. 15Departments of Radiology and Neurosurgery, Stony Brook University Medical Center, Stony Brook, New York, USA
  16. 16Department of Minimally Invasive Surgery, Edinburgh University, Edinburgh, USA
  17. 17Department of Neurosurgery, University of Florida, Gainesville, Florida, USA
  18. 18Department of Radiology, University of Virginia, Charlottesville, Virginia, USA
  1. Correspondence to Dr Waleed Brinjikji, Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN 55901, USA; brinjikji.waleed{at}


Background and purpose The HydroSoft coil was developed as a finishing coil, ideally to be placed along the aneurysm neck to enhance intracranial aneurysm healing. The GEL THE NEC (Gaining Efficacy Long Term: Hydrosoft, an Emerging, New, Embolic Coil) multicenter registry was developed to assess the safety and efficacy of HydroSoft coils in treating intracranial aneurysms. We report angiographic and clinical results of this prospective registry.

Materials and methods GEL THE NEC was performed at 27 centers in five countries. Patients aged 21–90 years with a ruptured or unruptured aneurysm 3–15 mm in size were eligible for enrollment. The following variables were obtained: demographics/comorbidities, aneurysm geometry, adjunctive devices used, proportion of patients in whom HydroSoft coils were successfully placed, and long-term angiographic outcomes (graded by an independent core laboratory using the Modified Raymond Scale), and procedure-related adverse events. Predictors of good angiographic outcome were studied using χ2 and t-tests.

Results A total of 599 patients with 599 aneurysms were included in this study. HydroSoft coils were successfully deployed in 577 (96.4%) patients. Procedure-related major morbidity and mortality were 0.5% (3/599) and 1.3% (8/599), respectively. The most common perioperative complications were iatrogenic vasospasm (30/599, 5.0%), thromboemboli (27/599, 4.5%), and aneurysm perforation (16/599, 2.7%). At last angiographic follow-up (mean 9.0±6.3 months), the complete occlusion rate was 63.2% (280/442) and near complete occlusion rate was 25.2% (107/442). The core laboratory read recanalization rate was 10.8% (46/425) and the retreatment rate was 3.4% (20/599).

Conclusions Endovascular treatment of intracranial aneurysms with HydroSoft coils resulted in complete/near complete occlusion rates of 88% and a major complication rate of 1.8%.

Trial registration number NCT01000675.

  • Aneurysm
  • Coil
  • Hemorrhage
  • Technology

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  • Contributors All authors made substantial contributions to (1) the conception or design of the work, or the acquisition, analysis, or interpretation of data for the work; (2) drafting of the work or revising it critically for important intellectual content; (3) final approval of the version to be published; and are in agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding The study was funded by Microvention.

  • Competing interests CM, HW, FH, PJ, OD receive research funding from MicroVention.

  • Ethics approval Multiple Institutional Review Boards.

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

  • Data sharing statement Data could be made available by contacting the corresponding author following IRB approval.