Chiari I Malformation: Opinions on Diagnostic Trends and Controversies from a Panel of 63 International Experts

BACKGROUND: Chiari I malformation (CMI) and the topics concerning it have been the subject of numerous discussions and polarizing controversies over the course of the last 20 years. METHODS: The opinions of 63 recognized international CMI experts from 4 continents, with a collective surgical experience of >15,000 CMI cases, were gathered through a detailed questionnaire. RESULTS: Three facts emerged from the analysis of the results. 1) Most of the replies showed a high level of consensus on most CMI-related topics. 2) Several topics, which had been considered controversial as recently as 10 years ago, are now more widely accepted. 3) The so-called 5-mm rule was rejected by 88.5% of the CMI experts who responded to the questionnaire. CONCLUSIONS: Sixty three recognized international CMI experts from 4 continents, with a collective surgical experience of >15,000 CMI cases were polled about a number of CMI topics. The results showed a high level of consensus, as well as a paradigm shift.