Delayed asymptomatic retroperitoneal dislodgement into the pouch of Douglas of a TLIF cage: A case report and review of the literature

BACKGROUND: Intraoperative anteropulsion of a transforaminal lumbar interbody fusion (TLIF) cage is infrequent but may have disastrous complications. Here, we present an 80-year-old female whose L5-S1 TLIF cage extruded anteriorly and later migrated into the pouch of Douglas (i.e. an anterior peritoneal reflection between the uterus and the rectum) posing potential significant risks/complications, particularly of a major vessel injury. Notably, this 80-year-old patient with degenerative lumbosacral scoliosis should have only undergone a lumbar decompression alone. CASE DESCRIPTION: An 80-year-old female underwent a two-level L4-L5 and L5-S1 TLIF to address lumbosacral canal stenosis with degenerative scoliosis. During the L5-S1 TLIF, intraoperative fluoroscopy showed the anterior displacement of the cage ventral to the sacrum. As she remained hemodynamically stable, the cage was left in place. The postoperative CT scan confirmed that the cage was located in the retroperitoneum but did not jeopardize the major vascular structures. Three months later, however, the cage migrated inferiorly into the pouch of Douglas. Although asymptomatic, general surgery and gynecology advised laparoscopic removal of the cage to avoid the potential for a major vessel/bowel perforation. However, the patient refused further surgery, and 3 years later remained asymptomatic. CONCLUSION: Anterior cage migration following TLIF has been rarely reported. In this case, an L5-S1 TLIF cage extruded anteriorly in an 80-year-old severely osteoporotic female and migrated 3 months later into the pouch of Douglas, posing the risk of a major vessel/bowel injury. Although surgical removal was recommended, the patient refused further surgery but remained asymptomatic 3 years later. Notably, the authors, in retrospect, recognized that choosing to perform a 2-level TLIF in an 80-year-old female reflected poor judgment.