A prospective open label 2–8 year extension of the randomised controlled ICON trial on the long-term efficacy and safety of occipital nerve stimulation in medically intractable chr... oleh Roemer B. Brandt, Leopoldine A. Wilbrink, Ilse F. de Coo, Joost Haan, Wim M. Mulleners, Frank J.P.M. Huygen, Erik W. van Zwet, Michel D. Ferrari, Rolf Fronczek, Michel D. Ferrari, Leopoldine A. Wilbrink, Ilse F. De Coo, Patty G. Doesborg, Eveline C. Bartels, Erik W. Van Zwet, Frank J.P.M. Huygen, Wim M. Mulleners, Erkan Kurt, Robert T.M. Van Dongen, Onno P.M. Teernstra, Peter J. Koehler, Geert H. Spincemaille, Frank Wille, Katja Burger, Joost Haan, Emile G.M. Couturier, Jan Willem Kallewaard, Peter H. Veltink, R. Buschman