gms | German Medical Science

65th Annual Meeting of the German Society of Neurosurgery (DGNC)

German Society of Neurosurgery (DGNC)

11 - 14 May 2014, Dresden

Is intracranial aneurysm rupture related to solar activity?

Meeting Abstract

  • Martin N. Stienen - Department of Neurosurgery, Kantonsspital St. Gallen, St. Gallen, Switzerland
  • Nicolas Roydon Smoll - Gippsland Medical School, Monash University, Melbourne, Australia; Frankston Hospital, Department of Surgery, Melbourne Australia
  • Marina Battaglia - Fachhochschule Nordwestschweiz FHNW, Hochschule für Technik, Institut für 4D-Technologien, Windisch, Switzerland
  • Bawarjan Schatlo - Department of Neurosurgery, Kantonsspital Aarau, Aarau, Switzerland
  • Christoph Woernle - Department of Neurosurgery, University Clinic Zürich, Zürich, Switzerland
  • Christian Fung - Department of Neurosurgery, Inselspital Bern, Bern, Switzerland
  • Michel Röthlisberger - Department of Neurosurgery, University Clinic Basel, Basel, Switzerland
  • Roy Thomas Daniel - Department of Neurosurgery, CHUV, Lausanne, Switzerland
  • Ali-Reza Fathi - Department of Neurosurgery, Kantonsspital Aarau, Aarau, Switzerland
  • Gerhard Hildebrandt - Department of Neurosurgery, Kantonsspital St. Gallen, St. Gallen, Switzerland
  • Karl Schaller - Department of Neurosurgery, University Clinic Geneva, Geneva, Switzerland
  • Philippe Bijlenga - Department of Neurosurgery, University Clinic Geneva, Geneva, Switzerland
  • SWISS SOS Investigators

Deutsche Gesellschaft für Neurochirurgie. 65. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Dresden, 11.-14.05.2014. Düsseldorf: German Medical Science GMS Publishing House; 2014. DocP 162

doi: 10.3205/14dgnc556, urn:nbn:de:0183-14dgnc5568

Published: May 13, 2014

© 2014 Stienen et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: A number of intrinsic and extrinsic risk factors for the rupture of intracranial aneurysms have been identified. Still, the cause precipitating aneurysm rupture remains unknown in many cases. In addition, it has been observed that aneurysm ruptures are clustered in time but the trigger mechanism remains obscure. As solar activity has been associated with cardiovascular mortality and morbidity we decided to study ist association to aneurysm rupture in the Swiss population.

Method: Patient data was extracted from the Swiss SOS database, at time of analysis covering 918 patients with angiography-proven aSAH treated at seven Swiss neurovascular centers between 01/01/2009 – 12/31/2011. The number of aneurysm rupture per day, week, month (Daily/Weekly/Monthly Rupture Frequency = RF) was measured and correlated to the absolute amount and the change in various parameters of interest representing continuous measurements of solar activity (radioflux (F10.7 index), solar proton flux, solar flare occurrence, planetary K-index/planetary A-index) using Poisson regression analysis.

Results: Of a consecutive series of 918 cases of SAH, precise determination of the date of symptom onset was possible in 816 (88.9%). During the period of interest there were 517 days without recorded aneurysm rupture. There were 398, 139, 27 and 12 days with 1, 2, 3, and 4 ruptures per day. Five or 6 ruptures were only noted on a single day each. Poisson regression analysis demonstrated a significant correlation of F10.7 index and aneurysm rupture (incidence rate ratio (IRR) = 1.006303; standard error (SE) 0.0013201; 95% confidence interval (CI) 1.003719 – 1.008894; p<0.001), according to which every 1-unit increase of the F10.7 index increased the count for an aneurysm to rupture by 0.63%. As the F10.7 index is known to correlate well with the Space Environment Services Center (SESC) sunspot number, we performed additional analyses on SESC sunspot number and sunspot area. Here, a likewise statistically significant relationship of both the SESC sunspot number (IRR 1.003413; SE 0.0007913; 95%CI 1.001864 – 1.004965; p<0.001) and the sunspot area (IRR 1.000419; SE 0.0000866; 95%CI 1.000249 – 1.000589; p<0.001) emerged. All other variables analyzed showed no correlation with RF.

Conclusions: Using valid methods, we found higher radioflux, sunspot number and sunspot area to be associated with an increased count of aneurysm rupture. Since we were using rupture frequencies rather than incidences and because we cannot explain the physiological basis of this statistical association, the clinical meaningfulness of this statistical association must be interpreted carefully. Future studies are warranted to rule out a type-1 error.