Guts and volume for hyperbolic 3-orbifolds with underlying space S³

Let O be a hyperbolic 3-orbifold with underlying space the 3-sphere. If O contains an essential 2-suborbifold with underlying space the 2-sphere with four cone points, we show how to compute the guts of O split along the 2-suborbifold. When the guts are non-empty, we obtain volume bounds in terms of the topology of the guts. When the guts are empty, we give a complete description of the topological structure of O.