Clinical Outcomes at One-year Follow-up for Patients With Surgical Site Infection After Spinal Fusion

Brian A. Karamian, MD; Jennifer Mao, BS, MBA,Gregory R. Toci, BS; Mark J. Lambrechts, MD; Jose A. Canseco, MD, PhD; Mahir A. Qureshi, BS; Olivia Silveri, BS; Paul D. Minetos, MD, MBA; Jack I. Jallo, MD, PhD; Srinivas Prasad, MD, MS; Joshua E. Heller, MD; Ashwini D. Sharan, MD; James S. Harrop, MD; Barrett I. Woods, MD; Ian David Kaye, MD; Alan Hilibrand, MD; Christopher K. Kepler, MD, MBA; Alexander R. Vaccaro, MD, PhD; Gregory D. Schroeder, MD


Spine. 2022;47(15):1055-1061. 

In This Article

Abstract and Introduction


Study Design: Retrospective case-control study.

Objective: To compare health-related quality of life outcomes at one-year follow-up between patients who did and did not develop surgical site infection (SSI) after thoracolumbar spinal fusion.

Summary of Background Data: SSI is among the most common healthcare-associated complications. As healthcare systems increasingly emphasize the value of delivered care, there is an increased need to understand the clinical impact of SSIs.

Materials and Methods: A retrospective 3:1 (control:SSI) propensity-matched case-control study was conducted for adult patients who underwent thoracolumbar fusion from March 2014 to January 2020 at a single academic institution. Exclusion criteria included less than 18 years of age, incomplete preoperative and one-year postoperative patient-reported outcome measures, and revision surgery. Continuous and categorical data were compared via independent t tests and χ 2 tests, respectively. Intragroup analysis was performed using paired t tests. Regression analysis for Δ patient-reported outcome measures (postoperative minus preoperative scores) controlled for demographics. The α was set at 0.05.

Results: A total of 140 patients (105 control, 35 SSI) were included in final analysis. The infections group had a higher rate of readmission (100% vs. 0.95%, P<0.001) and revision surgery (28.6% vs. 12.4%, P=0.048). Both groups improved significantly in Physical Component Score (control: P=0.013, SSI: P=0.039), Oswestry Disability Index (control: P<0.001, SSI: P=0.001), Visual Analog Scale (VAS) Back (both, P<0.001), and VAS Leg (control: P<0.001, SSI: P=0.030). Only the control group improved in Mental Component Score (P<0.001 vs. SSI: P=0.228), but history of a SSI did not affect one-year improvement in ΔMCS-12 (P=0.455) on regression analysis. VAS Leg improved significantly less in the infection group (−1.87 vs. −3.59, P=0.039), which was not significant after regression analysis (β=1.75, P=0.050).

Conclusion: Development of SSI after thoracolumbar fusion resulted in increased revision rates but did not influence patient improvement in one-year pain, functional disability, or physical and mental health status.


Elective lumbar spine surgery is often performed for the management of pain and functional disability due to spinal stenosis, spondylolisthesis, or disk herniations. The rate of these surgeries has increased 62.3% over the last decade (2004–2015).[1–5] Surgical site infections (SSIs) are among the most common healthcare-associated complications, with the prevalence of SSI after spine surgery ranging from 0.5% to 18%.[6–8] SSIs can be superficial (i.e., involving the subcutaneous tissues) or deep (i.e., involving the fascial and muscle layers).[9] Several factors including advanced age, immunosuppression, operative duration, dependent functional status, spinal instrumentation, and staged procedures have been shown to be associated with an increased risk of postoperative infection after spine surgery.[8,10–13] Given the morbidity, mortality, and healthcare expenditure associated with SSI, significant focus has been placed on addressing modifiable risk factors including smoking cessation, tight glycemic control, and antibiotic prophylaxis to decrease the risk for adverse outcomes.[14–18] Patients who develop SSI following spine surgery often have longer lengths of stay, greater risk of reoperation and 30-day mortality, and higher complication rates.[12]

While adverse surgical outcomes following SSI are well studied, the effects of postoperative infection on patient-reported outcomes remain to be elucidated.[19,20] Interpretation of previous studies on outcomes after spinal infection is challenging secondary to variability in outcomes assessments, inconsistencies in the definition of infection, and limited sample sizes.[19–21] As healthcare systems increasingly emphasize the value of delivered care, there is an increased need to understand the clinical impact of SSI on functional disability, pain, and health-related quality of life after spine surgery. The purpose of this study is to compare one-year patient-reported outcomes of patients who did and did not develop SSI after thoracolumbar fusion.