Investigating prevention, diagnosis and impact of surgical site infection

Surgical site infection (SSI) is the most common healthcare-associated infection, affecting up to 40% of surgical procedures depending on patient, operation, and specialty. Prevention and early recognition are essential to reducing morbidity and improving quality of life. Remote assessment offers opportunities to detect infections earlier, minimise patient travel and costs, and lessen environmental impact.
This thesis addresses the problem through a series of seven studies. Surveys of UK vascular surgeons and international practice reveal wide variation in SSI prevention across multiple domains, highlighting the absence of consensus. A systematic review of diagnostic test accuracy studies demonstrates that while remote assessment shows good screening potential for SSI (sensitivity 87.9%, specificity 96.8%), no research has assessed combined use of wound images and patient-reported data.
Building on these findings, a novel remote diagnostic tool—the ASSIST measure—was developed and validated. This 11-item instrument achieved excellent diagnostic accuracy (sensitivity 97.9%, specificity 92.5%, AUC 0.997). Subsequent studies quantified the impact of SSI on healthcare resources, showing a 62.5-fold increase in carbon emissions for patients with SSI compared to those without (643.8±1,276.4 vs 10.3±24.3 kgCO2e, p<0.001). Financial costs were similarly disproportionate (£8,355.08±18,144.84 vs £61.10±133.67 per patient, p<0.001). Implementing remote assessment in place of in- person review reduced emissions by 30.8±26.2 kgCO2e per patient (71.0% relative reduction, p<0.001) and lowered per-patient costs by £77.58 (87.0% relative reduction, p<0.001).
In conclusion, this thesis demonstrates significant variability in SSI prevention practices and the urgent need for evidence-based recommendations. The ASSIST measure shows high diagnostic accuracy and the potential to markedly reduce both financial and environmental burdens, supporting broader healthcare goals such as Net Zero 2045 and Darzi recommendations. Future work should assess this approach across other specialties and optimize remote delivery technologies.