Cauda equina, Primary cauda equina tumors, SEER, Spinal cord tumors, Adolescent, Adult, Aged, Aged, 80 and over, Cauda Equina, Child, Child, Preschool, Ependymoma, Female, Humans, Infant, Infant, Newborn, Male, Middle Aged, Neurilemmoma, Predictive Value of Tests, Retrospective Studies, SEER Program, Spinal Cord Neoplasms, Survival Rate, Treatment Outcome, Young Adult