The wound in the image corresponds to a postoperative lumbar dehiscence: the separation of the edges of a surgical incision that did not heal properly. It occurs when tissue closure fails due to bacterial infection, excessive tension on the suture, poor blood perfusion, or inadequate postoperative care.
In spinal surgeries, the lumbar region is especially vulnerable because it bears constant mechanical load, which makes the rest needed for healing difficult. A dehiscence of this degree requires surgical debridement, systemic antibiotics, and, in many cases, healing by secondary intention that can extend for weeks.
Without intervention, the risk of a deep infection reaching the vertebral structures is real and potentially fatal.