<s>[INST] I had surgery on my upper spine that I know nothing about. doctors tell me this after reading my xrays. I am adopted and was never able to obtain any info at all. my question is: what diagnosis would suggest surgery of the 4th and 5th disk to be fused together? [/INST] Hi, Welcome to HealthCareMagic.com I am Dr.J.Mariano Anto Bruno Mascarenhas. I have gone through your query with diligence and would like you to know that I am here to help you.Fusion of C4 and C5 is done (that is fusion of fourth bone and fifth bone in your neck) and Fusion of L4 and L5 (fourth and fifth bone of your lower spine) too is commonI have not seen some one with Fusion of disk. Can you please specify whether the Vertebral Bodies have been fused or whether the disc has been fused. If it is fusion of boneThen it can be commonly due to injuries or infections or degenerative diseases If you need any clarification / have doubts / have additional questions / have follow up questions, then please do not hesitate in asking again. I will be happy to answer your questions. In the future, for continuity of care, I encourage you to contact me directly in HealthCareMagic at  Best Wishes for Speedy Recovery Let me know if I can assist you further.Take care. </s>