What to do if i had surgery (tlif l4 5 l5 s1) and recently found out that what to do if i had a failed fusion.?

That depends on what: you mean by that-did the fusion not heal or did the fusion heal & you have persistent symptoms. 1st case may require another surgery to achieve fission. This may best be achieved by minimizing factors that affect healing like smoking in addition to a 360 surgery or front & back approach surgery with the addition of bone morphogenic protein to help with the fusion. If 2nd case, speak to your doc