Consider a closed 3$3$-manifold M$M$ and a knot K$K$ in M$M$.
Is it necessarily true that pi_2 (M \setminus K) = 0$\pi_2 (M \setminus K) = 0$?
If not, are there any conditions on M$M$ and/or K$K$ to ensure the above 2nd homotopy group of the knot complement is trivial?
Thanks!
(Note: This is, of course, true when M$M$ is simply connected --> S^3$S^3$)