Spondylolisthesis with spondylolysis in a 17-month-old: a case report.

Spondylolysis is frequently seen in adolescents, typically at the L5 vertebral level. While there may be a congenital predisposition for spondylolysis, it has long been suggested that the defect results from a fatigue or stress fracture of the pars interarticularis. Spondylolisthesis may result from a bilateral spondylolytic defect and is frequently asymptomatic. There is a paucity of literature on infant and toddler spondylolysis, as the focus is primarily on school-aged children, typically those over ten years of age. This case report presents an incidentally discovered L5 spondylolysis with spondylolisthesis in a 17-month-old female. The patient presented to the emergency department with multiple facial abrasions and bruises from reportedly being struck by her 4-year-old sister. Her past medical history included a hospitalization four months prior for a distal radius buckle fracture from a thirty foot fall from a window. A routine non-accidental trauma work-up was performed, including a skeletal survey which demonstrated L5 bilateral pars defect with Myerding grade 2 spondylolisthesis. An MRI of the lumbar spine was performed, again demonstrating the L5 bilateral pars defect with position dependent reduction of the spondylolisthesis. The patient was seen back in the orthopedic office three months later which is her latest follow-up. Dynamic plain films of the lumbar spine were unchanged from previous imaging, without evidence of instability or slip progression. Further progression of her slip should warrant consideration for further treatment, whether it be cast immobilization or surgery.