Evaluating the Negative Appendicectomy Rate: A Retrospective Observational Cohort Study at a UK Teaching Hospital Trust

Introduction The negative appendicectomy rate (NAR) serves as a key quality indicator in surgical practice, reflecting diagnostic accuracy and decision-making in suspected acute appendicitis. Despite improvements in imaging and clinical scoring systems, NAR in the United Kingdom remains higher than international averages. This study aimed to determine the NAR at East Lancashire Hospitals NHS Trust (ELHT), compare it with published benchmarks, and evaluate factors influencing diagnostic accuracy and clinical decision-making. Methods A retrospective observational cohort study was conducted at ELHT, encompassing all emergency appendicectomies performed between June 2023 and June 2024. Data were retrieved from electronic patient records and included demographics, clinical presentation, laboratory findings, imaging modality, and histopathology. Negative appendicectomy was defined histologically as the absence of inflammatory changes in the appendix. Subgroup analyses were performed by age, gender, and imaging use. Postoperative complications in negative appendicectomy cases were graded according to the Clavien-Dindo classification. A clinician survey assessed the utilisation of diagnostic scoring systems. Statistical analysis was performed using IBM SPSS Statistics version 31, with <i>p</i> < 0.05 considered significant. Results Of the 320 patients included, negative appendicectomy occurred in 59 cases (18.4%), with the NAR consistent with national data but higher than the international pooled estimate of 13%. Among 214 adults, the NAR was 15.9% (34); while among 106 children, the NAR was 23.6% (25) (p=0.0947). Female patients had a significantly higher NAR of 25.6% (33) compared with males at 13.6% (26) (p=0.0068). Preoperative imaging was performed in 176 cases (55.0%), with 50.8% (30) of negative appendicectomies occurring without imaging. Postoperative complications were observed in 6 negative cases (10.2%), all within Clavien-Dindo grade I-II. Thirty clinician survey responses revealed limited use of validated scoring systems in adult appendicitis, with 20 clinicians (66.7%) relying primarily on clinical intuition and experience. Conclusion The institutional NAR of 18.4% aligns with national figures but remains above international benchmarks. Higher rates among paediatric and female patients highlight persistent diagnostic challenges. Standardising diagnostic pathways through consistent use of validated clinical scoring tools such as the AIR and AAS scores, coupled with appropriate imaging, may enhance diagnostic accuracy, reduce unnecessary surgery, and improve patient outcomes.