40. Surgical Site Infection in Spinal Metastasis - Risk Factor and Countermeasure

Abstract

Study Design. A retrospective review (Phase 1) and prospective clinical study (Phase 2) Objectives. The objectives of this study were to identify independent risk factors for surgical site infection (SSI) and to evaluate the positive effect of prostaglandin E1 (PGE1) to decrease the risk of SSI in patients with spinal metastasis. Summary of Background Data. Surgery for spinal metastasis is associated with an increased risk of SSI. Although previous reports have evaluated risk factors of SSI for spinal metastasis, most of the studies lack multivariate analysis. A recent study demonstrated the utility of PGE1 in decreasing wound complications in patients with prior irradiation. The role of PGE1 in surgery for spinal metastasis has not been previously evaluated. Methods. 110 patients with spinal metastasis were retrospectively reviewed (phase 1). Risk factors for SSI were analyzed using logistic regression. Phase 2 was a prospective clinical trial investigating the utility of PGE1 at reducing the rate of SSI. 94 patients for with spinal metastasis were treated at our institute. The infection rate and risk factors identified in phase 1 and 2 were compared. Results. The rate of SSI during Phase 1 was 7.1%. Independent risk factors identified by multivariate logistic regression were diabetes, and preoperative irradiation. The rate of SSI for patients who had irradiation before surgery was 32%, while the rate for patients without irradiation was 1.1%. This difference was statistically significant. The rate of SSI in Phase 2 was 3.1%. In Phase 2 patients who received preoperative irradiation, the rate of SSI was 4.5%. The difference between Phase 1 and Phase 2 was statistically significant. Conclusions: This study identified diabetes and preoperative irradiation to be independent risk factors for SSI in patients with spinal metastasis. PGE1 administration was found to significantly decrease the incidence of SSI in patients with spinal metastasis who underwent preoperative irradiation. Introduction The purposes of surgical treatment for spinal metastasis are to avoid recurrence of the tumor, and to control spinal paralysis to maintain the patient's quality of life until the last moment. On the other hand, patients with spinal metastasis might have poor nutritional status and be prone to immunosupression from disease or treatments. Hence, the surgery for spinal metastasis is still controversial because it has potential risks of postoperative systemic complications. Recent literatures have reported excellent functional outcomes after the surgery for spinal metastasis with falling morbidity rates , although, the rate of complication remains relatively high compared to other spinal surgeries. Wise et al reported that the rate of complication was 25%. In all these reports, a major cause of morbidity was surgical site infection (SSI). SSI is one of the serious complications and may compromise the quality of outcome. A variety of risk factors for SSI in spinal surgery have been reported. Patient characteristics reported to increase the risk of SSI following spinal surgery are advanced age, preoperative malnutrition, presence of diabetes, preoperative or perioperative steroid therapy, and preoperative adjunctive therapy including chemotherapy or irradiation at the surgical site. Surgery-related risk factors reported to be associated