Given two m-tuples of commuting spectral operators on a Hilbert space, T = (T\,... ,T m ) and 5 = (Si S m ), an extended version of Henrici perturbation theorem is obtained for the joint approximate spectrum of S under perturbation by T. We also derive an extended version of Bauer-Fike theorem for such tuples of operators. The method used involves Clifford algebra techniques introduced by Mclntosh and Pryde.2000 Mathematics subject classification: primary 47 A13; secondary 34L05.