Single word request: ... but none of these practices explicitly justified

Background: varying reasons used for justifying brain tumour non-surgery lead to questionable outcomes. However, there can be cases where operation just couldn’t be done due to very poor health status.

I am trying to put this into one title, trying to say that none of the reasons can be considered as justified (surgery is always better). However, may I use the word explicitly here or are there better words? Unequivocal, unambiguous, clear…

High variability of reasons underpinning brain tumour non-surgery, but none of these practices explicitly justified