INTRODUCTION

Surgical site infection (SSI) is one of the most serious complications after spinal surgery. It is associated with high morbidity rates, high healthcare costs, and poor patient outcomes. Accurate identification of risk factors is essential in developing strategies to prevent devastating infections. This study aimed to identify independent risk factors for SSI following spinal surgery, using a prospective single-centered surveillance study method in analyzing preoperative patient and operative variables.

METHODS

We performed a prospective surveillance study of patients who developed SSI after undergoing spinal surgery at our hospital from July 2010 to June 2020. Only patients who underwent orthopedic spinal surgery were included in the study. Preoperative and operative patient characteristics were prospectively recorded using a standardized data collection format. The definition of SSI, as established by the Centers for Disease Control and Prevention, was followed. Patients who underwent surgery for the treatment of spinal infections were excluded from the analysis. Moreover, patients who underwent posterior instrumentation removal, percutaneous vertebroplasty, and endoscopic surgery, were also excluded. The recorded preoperative patient characteristics included age at the time of surgery, sex, height, weight, and surgical pathology (spinal trauma, spinal degenerative diseases, tumor or cancer, or spinal deformity). Preoperative patient-related risk factors for SSI included smoking status, diabetes mellitus, body mass index, American Society of Anesthesiologists score, hemodialysis, rheumatoid arthritis, previous spinal surgery, and preoperative steroid intake. In addition, surgery-related factors, considered as possible risk factors for SSI, were collected and analyzed. These included duration of operation, estimated blood loss, anatomic location (cervical, thoracic, and/or lumbosacral), emergency surgery, use of posterior instrumentation, intraoperative dural tear, and use of intraoperative fluoroscopy.

RESULTS

A total of 1578 patients who underwent spinal surgeries were enrolled, of which 28 (1.8%) developed postoperative SSIs. Multivariate regression analysis indicated three independent risk factors. Male sex (P = 0.023, odds ratio [OR] = 2.93, 95% confidence interval [CI] 1.16–7.46) was a statistically significant independent patient-related risk factor. The use of posterior instrumentation (P = 0.004, OR = 3.37, 95% CI 1.48–7.70) and use of intraoperative fluoroscopy (P < 0.001, OR = 6.75, 95% CI 2.32–19.67) were surgery-related independent risk factors. Microbiologic cultures were routinely taken in all 28 patients who developed SSI, and 85.7% (24/28) of the patients had wound infections associated with gram-positive organisms.

DISCUSSION

The male sex, use of posterior instrumentation, and use of intraoperative fluoroscopy, were shown to be independent risk factors for SSI after spinal surgery. Identification of these risk factors may be used to develop protocols aimed at decreasing the risk of SSIs. To the best of our knowledge, this is the first study to identify the use of intraoperative fluoroscopy as an independent risk factor for SSI after spinal surgery, using a prospective surveillance research method. Awareness of these risk factors can improve clinicians' risk perception in patients undergoing spinal surgery and may provide better patient counseling.