Previous research has shown there is baseline bacterial contamination of surgical spinal wounds prior to closure. While this bacterial contamination may or may not lead to infection, recent adult studies demonstrated reduced infection rates by using povidone-iodine irrigation before closure. This study will determine the safety of using povidone-iodine irrigation in pediatric spinal patients and how effective it is at reducing bacterial contamination of the spinal surgical wound prior to closure, compared with normal saline. The investigators hypothesize povidone-iodine is both safe and effective. Understanding techniques that reduce the local bacterial load in the wound prior to closure after spinal fusion will give data to support measures that will ultimately reduce the rate of postoperative infections.