What is the ruling on a woman exposing her awrah to a male doctor for a necessary surgery after it has become impossible to find a female specialist?

The fundamental principle is that a woman should seek treatment from another woman. Every effort should be made to find a female expert to perform the procedure, especially if it concerns the grave 'awrah (private parts that are strictly to be concealed). However, if no woman is available, and there is an urgent need for treatment from a man, then there is no harm in that, provided that he does not see or touch more than what is necessitated by the need.