P0836 - Long Term Outcomes Following Surgical Site Infections in Early Onset Scoliosis Patients: A 15-year Retrospective Review

Introduction
Deep surgical site infections (SSIs) are a common and potentially severe complication in early onset scoliosis (EOS) patients. What are long-term outcomes after a patient develops a SSI? Are there additional risks associated with multiple infections? Can the instrumentation be retained following SSI?

Methods
We performed a retrospective review of all EOS patients who underwent growing spine procedures from 2003 to 2017. Inclusion criteria were patients with ≥1 SSI according to Centers for Disease Control and Prevention (CDC) criteria. SSIs were categorized as a single or multiple infections. All were treated with operative irrigation and debridement as well as intravenous and oral antibiotics. Univariate analysis was performed on the data using chi-square and ANOVA tests to assess differing factors between patients with single versus multiple infections.

Results
Ninety patients underwent 690 growth-friendly surgical procedures. 24 patients (27%) developed a total of 32 SSIs (4.6% SSI per procedure). Of these patients, 17 had one infection and 7 patients had multiple infections. Tables 1 and 2 detail the patient demographics and infection characteristics. Demographics were not significantly different based on sex, age, etiology, or mean length of follow up between the infection groups.

We sought to identify differences between patients who had one infection limited to a single episode compared to those who developed repeat SSIs. Patients were therefore separated into two groups: those with a single versus multiple SSIs. Infections were then subdivided into three groups: initial SSI in patients with no subsequent SSI, initial SSI in patients who developed another SSIs, and recurrent SSIs. ANOVA and chi-squared tests were performed between these three groups, which showed a significant difference in the number of procedures after infection and nasal staphylococcus screen results among groups (p = 0.0063 and 0.00132 respectively). Pairwise/post-hoc tests revealed that index infections preceding recurrent infections were associated with an increased number of procedures after infection (i.e. occurring earlier in the lengthening process) (p. value = 0.0044584) and positive nasal screens (p < 0.05) compared to index infections in the isolated single infection group.

All 24 patients had resolution of their SSIs. Twenty-one patients reached final instrumented fusion; one is still actively undergoing lengthening. Three patients, all of whom had multiple infections, underwent complete removal of instrumentation. Reasons included parental request (termination of treatment), and infection >7 years after final fusion.

Conclusions:
Most patients who develop SSIs during growing spine treatment are able to retain instrumentation without need for early treatment termination. Risk factors most associated with having multiple SSIs include having an earlier infection in the course of growing spine surgery and a resultant higher number of procedures following an index infection, and having a positive nasal screen on the day of surgery.