Incompressible surfaces and spunnormal form

Suppose M is a cusped finite-volume hyperbolic 3-manifold and T{\mathcal{T}} is an ideal triangulation of M with essential edges. We show that any incompressible surface S in M that is not a virtual fiber can be isotoped into spunnormal form in T{\mathcal{T}}. The proof is based directly on ideas of W. Thurston.