OBJECTIVE AND IMPORTANCEThis case report illustrates an uncommon complication from the retroperitoneal exposure of the lumbar spine. The diagnosis and management of a retroperitoneal lymphocele is presented. The lymphocele was treated with intralesional povidone iodine (Betadine; Purdue-Frederick, Norwalk, CT), which eradicated the lesion and provided symptomatic relief to the patient.CLINICAL PRESENTATIONA young woman developed an iatrogenic, rapidly progressive spondylolisthesis after having undergone three previous lumbar surgeries for radiculopathy at the L5–S1 level.INTERVENTIONA back-front-back approach was used for operative reduction and fusion of the spondylolisthesis. The patient’s postoperative course was complicated by a retroperitoneal lymphocele. She presented with symptoms of urinary urgency and incontinence. The lymphocele was successfully treated with repeated drainage and sclerosis with povidone iodine. The patient ultimately developed a solid fusion, and her pain resolved.CONCLUSIONA retroperitoneal lymphocele is an uncommon complication caused by the surgical exposure of the lumbar spine when a ventral approach is used. In this case, it was diagnosed and treated without further surgical intervention.