Treatment of isolated serosanguinous incision drainage after thoracolumbar surgery: Is surgical management always necessary?

Background: There is no consensus regarding how to care for a patient presenting with early isolated incision drainage after thoracolumbar spine surgery. Although drainage is the most common presenting symptom of surgical site infection (SSI), it has low specificity for SSI in the absence of other symptoms. Given that invasive treatment for SSI is costly and high risk, it would be beneficial to determine whether antibiotic treatment alone is sufficient for isolated drainage and what factors predispose to failure of this conservative strategy. Methods: The authors retrospectively reviewed a clinical database of patients who underwent thoracolumbar spine surgery at a single center between 2012-2017. Patients were included if serosanguinous drainage was present within six weeks of surgery without other signs and symptoms of infection such as fever, chills, purulent discharge, fluctuance, wound dehiscence, or erythema. Results: Fifty-eight patients met the study inclusion criteria. After initial conservative management with antibiotics, drainage resolved in 51 patients. The seven patients with drainage that did not resolve were treated with operative surgical washout. Although the groups were similar in most respects, there was a significant difference in the American Society of Anesthesiologists (ASA) score, which is a marker of overall health (surgical group score 2.89 ± 0.33 versus 2.06 ± 0.61; p < 0.0001). In addition, patients with greater estimated blood loss, length of hospital stay, operative time, and spinal levels treated were more likely to require surgical washout, although these differences were not statistically significant. Groups were similar with respect to age, Body Mass Index, smoking status, diabetes mellitus status, revision versus primary surgery, and drainage latency. Conclusion: Most patients who present with isolated serosanguinous incision drainage within six weeks of surgery may be managed successfully using antibiotics only. Patients who fail to respond to conservative therapy have significantly worse general health, as indicated by the ASA score.