  We present the first results of a self-consistent solution of the
semiclassical Einstein field equations corresponding to a Lorentzian wormhole
coupled to a quantum scalar field. The specific solution presented here
represents a wormhole connecting two asymptotically spatially flat regions. In
general, the diameter of the wormhole throat, in units of the Planck length,
can be arbitrarily large, depending on the values of the scalar coupling $\xi$
and the boundary values for the shape and redshift functions. In all cases we
have considered, there is a fine-structure in the form of Planck-scale
oscillations or ripples superimposed on the solutions.
