For that purpose, a BTX ECM 830 Harvard Apparatus was used. The electric pulses consisted of thirty-two square pulses of 300V, 100 μs long at 1 Hz. The electrode was rotated 90 de grees clockwise and the pulses were repeated. After the rotation, the electrode was removed 2 cm and the whole procedure was repeated until com plete coverage of the nasal duct It was not possible to treat safety margins due to the location of the tumors.