The document summarizes the retroperitoneal approach to the lumbar spine. It describes the indications, patient positioning, incision details, and steps of the surgical dissection. These include splitting the external oblique, internal oblique, and transversus abdominis muscles to expose the retroperitoneal space. The peritoneum and its contents are then retracted to reveal the lumbar spine and vessels. The segmental vessels are ligated to provide access to the vertebral bodies after level confirmation with imaging. Care must be taken to avoid injury to nearby structures like the ureter and sympathetic chain during the procedure.