Oral Presentation 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

INTRODUCTION

It’s been long known that surgical site infections (SSIs) are a potential risk associated with undergoing spinal surgery. However, an intensified examination of this complication is both appropriate and warranted in light of the current medical landscape, including increasing antimicrobial resistance, significant SSI-associated economic implications, and the increasing proportion of elderly or complex patients undergoing spine surgery. It remains unclear if MIS techniques ultimately produce significantly decreased SSI rates in lumbar fusion surgery compared to open or mini-open. Therefore, the primary goal of this study was to investigate the difference in SSI rates for different surgical techniques in patients undergoing lumbar fusion.

METHODS

This is a retrospective review of all patients who underwent 1 or 2-level instrumented posterior lumbar fusion between 01/2019 and 06/2022. Three cohorts (Mini, MIS, and Open) were created to divide patients based on the surgical technique utilized. SSIs were identified according to the Centers for Disease Control and Prevention’s National Healthcare Safety Network (CDC/NHSN) criteria. Superficial SSIs involved only skin and subcutaneous tissue of the incision, Deep involved deep soft tissues of the skin, and Organ/Space involved surgeries in which a body part was opened/manipulated deeper than fascial/muscle layers.

RESULTS

1,382 surgeries performed in 1,352 patients were included. The mean age was 61.5 ± 12.8 years, and the mean BMI was 28.7 ± 5.67 kg/m². The traditional open surgical technique was utilized in most of the surgeries (39.3%, 543), followed by Mini (33.1%, 458), and MIS (27.6%, 381). The overall SSI rate following lumbar fusion surgery was 0.94%. MIS cases had the lowest infection rate (0.3%, 1) followed by Mini (1.1%, 5) and Open (1.3%, 7). 13 patients developed an SSI, 2 were superficial, 5 were deep, and 6 were organ/space. 12 (92%) patients underwent a subsequent irrigation and debridement (I&D) procedure. All pathogens were gram-positive. 

DISCUSSION

In our cohort, cases performed using MIS techniques had the lowest SSI rate, followed by Mini-open techniques and the traditional open technique; however, the difference in SSI development by technique was not statistically significant. The overall SSI rate in the present cohort of 0.94% exhibits an incidence considerably lower than values reported in the literature for posterior lumbar fusion. This result is likely the most compelling takeaway from the present investigation as it highlights the notion that the risk of SSIs can be significantly minimized. While the study was not designed to elucidate what practices can reduce SSIs, the positive results are likely explained by a multifactorial set of institutional and surgical practices, including preoperative antibiotic prophylaxis, robust sterilization procedures, specialized air OR filtration systems, thorough skin preparation, and meticulous dissection and closure.  

Given the low incidence of SSIs in our data, it cannot be reasonably concluded whether differences attributable to surgical technique exist; however, our data exemplifies that achieving significantly lower SSI rates than those reported in the literature is a practical goal, and thus, all institutions should aim to evaluate and implement the SSI mitigation strategies supported by the current evidence.