ALIF and OLIF reach the same disc by different paths, and both run past what must not be touched. In front sit the aorta, the inferior vena cava and, at L5-S1, the iliac bifurcation, which is what decides, patient by patient, whether the anterior route is viable.
Lumbar Anterior-Lateral brings both approaches in one piece, from L3 to S1. The abdominal wall is genuinely layered: Camper's fascia, external oblique, internal oblique, transversus, rectus abdominis and Scarpa's fascia. Behind it, the peritoneum, the peritoneal fat, the ureter, the psoas and the iliacus.
The great vessels and the peritoneum are separate modules. That matters to the training budget: what gets discarded is what was used, not the whole assembly.
