Things happen following surgery
and it appears your surgeon is willing to 'eat the costs' as you say to give you a better result. The stones have nothing to do with your surgery. But the fluid collection does. Trust your surgeon to do the best job he can do for you, especially since he is willing to pay for it.
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I genuinely suspect any information you would get from a site like this would be far less valuable than a conversation with your surgeon or someone in his office. Postop complications are always a challenge and no one will be more invested in your recovery than your surgeon.