<s>[INST] I had back surgery back in 2009 on L2-3,L3-4 AND L4-5 I had a 360 done in order for the doctor to get to all the discs involved. Why do I now have a right posterior lateral disc herniation with the appearance of an extruded fragment postereolaterally on the right at L5-S1 and a mild buldge at L1-2? [/INST] Hi there Thanks for your question at ChatDoctorDisc herniation is one step in the natural history of disc degeneration. Once some part of the spine is fused, the segments adjacent to the fused part of spine, is subjected to more stress, as the movements at the segment are increased and hence undergoes earlier degeneration. This is known as adjacent segment degeneration, which can present as disc herniation. Long segment fusion, which can be said as more than 2 levels fusion(as in your scenario) is more commonly associated with such degeneration. Such a degeneration is also more likely to happen, if you are more than 60 years old and there were signs of some degeneration in these discs prior to the fusion surgery Hope this answers your question. All the best  </s>