Related Experiment Video
Updated: May 9, 2026
In Vivo Mouse Model of Spinal Implant Infection
Published on: June 23, 2020
Does minimally invasive surgery have a lower risk of surgical site infections compared with open spinal surgery?
Wen Wei Gerard Ee1, Wen Liang Joel Lau, William Yeo
1Department of Orthopaedics, Singapore General Hospital, Outram Road, Singapore, 169 608, Singapore, gerardee@gmail.com.
Background:
Surgical site infection (SSI) ranges from 1.9% to 5.5% in most large series. Minimally invasive surgery (MIS) has been postulated to reduce SSI rates.
Questions/Purposes:
(1) Is MIS associated with a lower incidence of SSI compared with open spinal surgery? (2) Are there other independent risk factors associated with SSI? (3) What bacteria are most common in spinal SSI?
Methods:
Medical records of 2299 patients who underwent transforaminal lumbar interbody fusion, laminectomy, or discectomy were analyzed and selected for a nested case-control analysis. Twenty-seven cases with SSI were matched with 162 control subjects without SSI stratified based on procedure performed within 28 days of the case's date of surgery. Patients were identified from an institutional database at a tertiary care hospital. MIS involved spinal procedures performed through a tubular retractor system. Univariate and multivariate analyses were performed.
Results:
Patients undergoing open spinal surgery were 5.77 times more likely to develop SSI compared with MIS approaches (odds ratio [OR], 5.77; 95% confidence interval [CI], 1.0-32.7; p = 0.048). Also, from the multivariate regression model, diabetes (OR, 4.7; 95% CI, 1.3-17.0; p = 0.018), number of levels operated on (OR, 3.5; 95% CI, 1.6-7.5; p = 0.001), and body mass index (OR, 1.2; 95% CI, 1.0-1.3; p = 0.010) were predictive of an increased risk in SSI. Staphylococcus aureus was most frequently identified, being present in 12 of 21 (52.4%) patients in whom positive cultures were obtained. Four of the 12 patients had methicillin-resistant S aureus infection.
Conclusions:
In our series, MIS has a lower incidence of SSI. The risk factors predictive of SSI should be further evaluated in well-designed prospective trials.
Level Of Evidence:
Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
Insights
Minimally invasive surgery (MIS) significantly reduces surgical site infection (SSI) risk compared to open spinal surgery. Diabetes, increased levels operated, and higher BMI are key SSI risk factors.
Area of Science:
- Spinal Surgery
- Infectious Disease
- Minimally Invasive Procedures
Background:
- Surgical site infection (SSI) rates in spinal surgery range from 1.9% to 5.5%.
- Minimally invasive surgery (MIS) is hypothesized to decrease SSI incidence.
Purpose of the Study:
- To compare SSI incidence between MIS and open spinal surgery.
- To identify independent risk factors for SSI.
- To determine common bacterial pathogens in spinal SSI.
Main Methods:
- A nested case-control analysis of 2299 patients undergoing spinal procedures.
- Comparison of 27 SSI cases with 162 controls.
- Analysis included univariate and multivariate regression models.
Main Results:
- MIS approaches were associated with a 5.77-fold lower risk of SSI compared to open surgery (p=0.048).
- Independent risk factors for SSI included diabetes (OR 4.7), number of levels operated (OR 3.5), and BMI (OR 1.2).
- Staphylococcus aureus was the most common pathogen (52.4%), including methicillin-resistant S. aureus.
Conclusions:
- MIS is associated with a lower incidence of SSI in spinal surgery.
- Further prospective studies are needed to evaluate identified SSI risk factors.
