Retroperitoneal fluid collection following anterior spine surgery--differential and management.

Iatrogenic ureteral injuries are rare and must be accurately identified to minimizing the risk for additional complications. Anterior lumbar interbody fusion (ALIF) is a valuable technique utilized in spine surgery, with its own unique set of complications. For example, retroperitoneal fluid collections, following ALIF surgery are rare and may result in back pain, radicular pain, nausea, and even death. It is important to rapidly identify the nature of the fluid collection to clarify appropriate management options. The purpose of this case report is to present a differential diagnosis for a delayed presentation of an extremely large retroperitoneal fluid collection following anterior lumbar surgery, as well as to provide discussion on this rare complication. Specifically, a 51-year-old female with a history of numerous previous abdominal surgeries underwent an L3-S1 ALIF through a paramedian retroperitoneal approach. Postoperatively, she developed a large retroperitoneal fluid collection heralded by unilateral left lower extremity swelling and paresthesias. Fluid aspiration suggested a urine leak, but no specific injury was identified on retrograde pyelogram, most likely due to hardware obscuration in the area of presumed injury. A presumptive ureteral injury resulted in a ureteral stent placement, with resolution of the fluid collection and hydronephrosis. A high index of suspicion allowed for proper treatment, healing, and ultimately, a satisfactory outcome.