Abstract

Background
Acute appendicitis is the most common surgical emergency in children. While up to 85% of pediatric appendicitis cases are uncomplicated, the rate of complicated appendicitis can be significant, ranging from approximately 30% overall to as high as 50–75% in certain cohorts [1]. Ultrasound (US) is a first-line imaging modality, yet its diagnostic performance in accurately identifying these complications remains uncertain [2].

Methods
Following PRISMA [3], we searched PubMed, Embase, Web of Science, and Scopus from inception. Risk of bias was assessed with QUADAS-2. Bivariate random effect model pooled sensitivity and specificity; heterogeneity was summarized using I² and Q; small-study effects were evaluated using Deeks’ test. Clinical utility was illustrated using a Fagan nomogram, and overall accuracy was assessed using a summary receiver-operating characteristic (SROC) curve.

Results
Twenty-one studies met the inclusion criteria. Nearly all procedures were conducted by specialists or residents in radiology. The age range for the pediatric population was between 0 to 18 years old. Pooled US sensitivity for identifying complicated appendicitis was 0.52 (95% CI 0.41–0.62), and specificity was 0.90 (0.84–0.94) (Figure 1). The area under the curve was 0.80 (0.76–0.83) (Figure 2), and the summary operating point mirrored the pooled estimates. Deeks’ test suggested no significant asymmetry (p=0.08). Assuming a pre-test probability of 25%, a positive US result (LR+ = 5) increased the post-test probability to ~64%, whereas a negative result (LR–=0.54) reduced it to ~15%.

Conclusion
In pediatric appendicitis, US demonstrates high specificity but moderate sensitivity for discriminating complicated from simple disease. A positive scan can “rule in” complication and support expedited, targeted management; a negative scan cannot exclude complication and should be interpreted alongside clinical findings, laboratory data, and, when indicated, adjunct imaging. Future studies should standardize sonographic criteria and report per feature performance to refine thresholds and reduce heterogeneity.

Author contributions
All authors contributed equally and validated the final version of record.
Declarations
Conflicts Of Interest
The Authors declare that there is no conflict of interest.
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Registration
No registration applicable.
Data availability statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Ethical approval
Ethical approval for this study was not required.

References

1.      Benabbas R, Hanna M, Shah J, Sinert R. Diagnostic accuracy of history, physical examination, laboratory tests, and point‐of‐care ultrasound for pediatric acute appendicitis in the emergency department: a systematic review and meta‐analysis. Acad Emerg Med. 2017 May;24(5):523–51. https://doi.org/10.1111/acem.13181

2.      Badlis M, Amari K, Alkheshi M, Alolaby K, Alsaid B. Ultrasound and computed tomography in differentiating between simple and complicated appendicitis in pediatric patients. Pediatr Surg Int. 2024 Nov 9;40(1):299. https://doi.org/10.1007/s00383-024-05880-0

3.      Sarkis-Onofre R, Catalá-López F, Aromataris E, Lockwood C. How to properly use the PRISMA Statement. Syst Rev. 2021 Apr 19;10(1):117. https://doi.org/10.1186/s13643-021-01671-z