The Surgical Site Infection Risk Score (SSIRS): A Model to Predict the Risk of Surgical Site Infections

Abstract

BackgroundSurgical site infections (SSI) are an important cause of peri-surgical morbidity with risks that vary extensively between patients and surgeries. Quantifying SSI risk would help identify candidates most likely to benefit from interventions to decrease the risk of SSI.MethodsWe randomly divided all surgeries recorded in the National Surgical Quality Improvement Program from 2010 into a derivation and validation population. We used multivariate logistic regression to determine the independent association of patient and surgical covariates with the risk of any SSI (including superficial, deep, and organ space SSI) within 30 days of surgery. To capture factors particular to specific surgeries, we developed a surgical risk score specific to all surgeries having a common first 3 numbers of their CPT code.ResultsDerivation (n = 181 894) and validation (n = 181 146) patients were similar for all demographics, past medical history, and surgical factors. Overall SSI risk was 3.9%. The SSI Risk Score (SSIRS) found that risk increased with patient factors (smoking, increased body mass index), certain comorbidities (peripheral vascular disease, metastatic cancer, chronic steroid use, recent sepsis), and operative characteristics (surgical urgency; increased ASA class; longer operation duration; infected wounds; general anaesthesia; performance of more than one procedure; and CPT score). In the validation population, the SSIRS had good discrimination (c-statistic 0.800, 95% CI 0.795–0.805) and calibration.ConclusionSSIRS can be calculated using patient and surgery information to estimate individual risk of SSI for a broad range of surgery types.

Evaluating the use of antibiotic prophylaxis during open reduction and internal fixation surgery in patients at low risk of surgical site infection

“…The recognised SSI risk factors include patients' general health and certain comorbidities, such as diabetes and peripheral vascular disease [15,22,25,27,34]. The type of fractures (low vs. high energy), number of implants, duration of surgery, and surgical site/wound condition (open vs. closed fracture) are also independent and significant risk factors that predispose patients to SSI [17,23,27,33]. To design a simple SSI scoring method that is easy to understand and use in our practice, we included in the scorecard the patient's general health status, primary cause of fractures, skin and soft tissue (e.g., fascial and muscle layers) conditions surrounding the surgical site, type of implants used for internal fixation, and surgical duration.…”

“…We designed a SSI risk factor scorecard (Table 1) by considering five major SSI risk factors associated with ORIF surgeries according to related literature about SSI in surgical patients [15,22,24,25,31,33,34]. Each risk factor was assessed as low (1 point), medium (2 points), or high (5 points).…”

The Importance of Perioperative Prophylaxis with Cefuroxime or Ceftriaxone in the Surgical Site Infections Prevention after Cranial and Spinal Neurosurgical Procedures

“…The risk is higher in case of craniotomies compared to spinal procedures [35], whereas, in clean neurosurgical procedures there had been SSI in 2.24% compared to 20% in case of contaminated [36]. Significant procedural risk factors for SSI are urgent as opposed to elective neurosurgical procedures, clean-contaminated and contaminated surgical interventions, ACA score 3, performing more than one procedure during the surgical intervention, as well as duration of the operative intervention more than 4 hours [37,38,39,40].…”

“…[37,21,42], and also, in addition to the patient's specifics and the neurosurgical intervention, also important are the specifics related to the institution, operational room, skin preparation, disinfection, the experience of the surgeon, season, and many other [35].…”

“…Careful determination of all potential risk factors of postoperative SSI after neurosurgical procedures and their precise quantification and stratification is of high importance, not only related to the consequences for the patient and the institution (health and financial), but also, for the possibility of inter and intra-institutional comparison (the experience of the surgeon is also an important and measurable indicator), and the possibility of making adequate strategic decisions for undertaking specific preventive measures, especially because the benefit for the patient of such strategic approaches is inversely associated with the basic/primary risk of their occurrence [37].…”