Interpreting Abdominal Surgical-Site Infection Trends Across the COVID-19 Shock: A Critical Narrative Review and the SSI Signal-Validity Framework

Background/Objectives: Comparisons of abdominal Surgical-Site Infection (SSI) rates during COVID-19 often treat recorded incidence as a direct measure of biological risk, although the pandemic altered operative volume and case mix, prevention practices, and post-discharge detection. This review examines when reported SSI changes are interpretable. Methods: We conducted a critical narrative review, informed by SANRA and critical interpretive synthesis, of MEDLINE/PubMed, Embase, Scopus, and Europe PMC (January 2018–25 June 2026). Comparative SSI studies formed the core evidence set, supported by contextual studies on emergency presentation, biological risk, prevention, and surveillance. Results: Studies reported lower, unchanged, non-monotonic, and higher SSI rates. These differences became more coherent when the recorded rate was separated into operative composition, true infection probability, and detection probability. No core study measured all domains required to isolate a biological pandemic effect. Evidence from acute pancreatitis and abdominal trauma showed that disease severity, care access, inflammatory status, and prognostic relationships varied with health-system context. Conclusions: We propose the Surgical-Site Infection Signal-Validity Framework (SSI-SVF). It classifies findings as probable true improvement, apparent improvement, masked deterioration, mixed deterioration, or indeterminate and requires joint assessment of operative composition, true infection risk, and detection probability before interpreting a calendar-period change as altered surgical safety.