What are the long term side effects of BBL?

The most common questions here surround the short term. I'm more concerned about the longer term issues. After surviving the surgery and escaped all short term risks, are there long term risks to worry about? I've read some reviews where girls complained about experiencing pain when sitting down as long as one year after surgery. Is this common? How can this be avoided and are there any other long term issues? I'm talking 10years, 50years.