Spinal fusion surgery techniques develop together with technologic advancements. New complications are seen as the result of new techniques and these may be very severe due to spinal cord and vascular structures in the lumbar region. The posterior lumbar interbody fusion cage (PLIFC) was shown to enhance spinal fusion and to prevent pseudoarthrosis due to its basic dynamic characteristics. PLIFC migrations are usually observed during the postoperative period, just after the mobilization of the patient and usually toward spinal canal. Migration to the retroperitoneal region is a extremely rare condition in the literature. In this article we discussed three cases of PLIFC antepulsion into the retroperitoneal region during the intraoperative period.