P21. Skin closure with skin staples may have increased risk for surgical site infection compared to running subcuticular stitch with absorbable suture in posterior thoracolumbar surgery

Surgical site infections (SSIs) can add significant costs to patient care as well as societal and personal costs. SSI can start prior to or after the wound closure. For the latter, the infection most likely occurs through the incision. Optimal surgical wound skin closure method would provide good cosmesis while minimizing the risk for SSI. In the spine literature, there is some evidence that there may be increased risk for SSI when the skin is closed with surgical staples versus other closure methods. In a recent international survey, skin closure with skin staples (SS), nylon skin sutures, and absorbable sutures were all frequently used by spine surgeons. In our institution, two most common methods for skin closure are skin staples (SS) or running subcuticular stitch with absorbable suture (RSAS). To compare risk for SSI in posterior thoracolumbar spine surgery wounds closed by SS or RSAS. Retrospective cohort study in a single academic center with multiple surgeons. All patients who had posterior thoracolumbar surgery between July 1, 2018, to June 30, 2020, in the Spine Surgery division at a tertiary referral academic medical center. Rates of return to the operating room (ROR) for SSI within one year of the index surgery in posterior thoracolumbar cases closed using SS or RSAS. After IRB approval, a retrospective review of billing and hospital records was used to obtain all spine surgeries done between July 1, 2018 to June 30, 2020. Inclusion criteria were posterior thoracolumbar surgeries and age >18. Exclusion criteria were oncologic condition and previous infection in the surgical site. We identified 1215 surgical cases. In 2 cases, we could not determine the skin closure type and in 11 cases, nylon skin suture was used to close the skin, leaving 1202 cases in our study. There were no infections in the 13 excluded cases. We used the operative note, the Supplies Section in the electronic medical record (EMR) that showed what suture or staples were used during the surgery, and progress notes to determine the skin closure method for each case and whether vancomycin powder was applied in the wound prior to wound closure. We obtained demographic and clinical history such as age, BMI, history of smoking or diabetes from the history section of the EMR. We determined the surgical characteristics such as previous surgery in the same site, cases with instrumented fusions, and the number of levels fused in each case using pre- and peri-operative notes. Chi Squar