Does CT Reduce the Rate of Negative Laparoscopies for Acute Appendicitis? A Single-Center Retrospective Study

2024 Clinical Practice Guideline Update by the Infectious Diseases Society of America on Complicated Intra-abdominal Infections: Diagnostic Imaging of Suspected Acute Appendicitis in Adults, Children, and Pregnant People

This paper is part of a clinical practice guideline update on the risk assessment, diagnostic imaging, and microbiological evaluation of complicated intra-abdominal infections in adults, children, and pregnant people, developed by the Infectious Diseases Society of America (IDSA). In this paper, the panel provides recommendations for diagnostic imaging of suspected acute appendicitis. The panel's recommendations are based on evidence derived from systematic literature reviews and adhere to a standardized methodology for rating the certainty of evidence and strength of recommendation according to the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach.

"Amr Sign": A Case-Control Study Evaluating the Diagnostic Value of a New Clinical Sign in the Diagnosis of Acute Appendicitis

Introduction Acute appendicitis, a prevalent cause of acute abdominal pain and a common indication for emergency surgery, presents a diagnostic challenge due to its diverse clinical presentation and variability in appendix location and symptoms. Traditional diagnostic approaches, including physical examination, clinical scoring systems, and imaging techniques, have limitations. This study introduces the "Amr sign," a new diagnostic indicator characterized by sudden reflex hyperextension of the neck upon palpation of the right iliac fossa, which is hypothesized to reflect local peritoneal irritation from an inflamed appendix. Methods We conducted a prospective observational study at Alwakra Hospital from November 2016 to January 2019 that included 195 patients aged 15 years and older with right iliac fossa pain and an Alvarado score of four or more. The "Amr sign" was evaluated alongside standard clinical examination and imaging results. Diagnostic accuracy was assessed via histopathological confirmation, which is the gold standard. Results The "Amr sign" had a sensitivity of 68.6% and a specificity of 67.3%. The positive predictive value (PPV) was 89%, whereas the negative predictive value (NPV) was 45%. Receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.679 for the "Amr sign" compared with 0.622 for the other imaging modalities, suggesting comparable diagnostic performance. The "Amr sign" demonstrated a higher likelihood ratio of a positive test (2.3) and a lower likelihood ratio of a negative test (0.46). Conclusion The "Amr sign" is a promising diagnostic tool for acute appendicitis, offering a simple, reliable, and quick test that can be performed by less experienced physicians. While its sensitivity and specificity are moderate, its high PPV suggests that it is particularly useful in confirming appendicitis. Further research and validation are needed to fully establish its role in clinical practice.

Other Pathologies Were Rarely Reported after Laparoscopic Surgery for Suspected Appendicitis: A Systematic Review and Meta-Analysis

BACKGROUND

Diagnostic laparoscopy is often used when a patient is suspected of having acute appendicitis. The aim of this study was to assess the rate of other pathologies found during diagnostic laparoscopy for suspected acute appendicitis.

METHODS

This systematic search included studies with ≥100 patients who received laparoscopy for suspected acute appendicitis and reported on the histopathologic and other intra-abdominal findings. We performed a meta-analysis estimating the rate of other pathologies, and a sensitivity analysis excluding smaller cohorts (≤500 patients). Age groups, sex, specific findings, and geographic regions were investigated. Certainty of evidence was assessed with GRADE.

RESULTS

A total of 27 studies were included covering 25,547 patients and of these 793 had an unexpected pathology. The findings were benign pathology in the appendix (34%), malignancy (30%), gynecologic pathology (5%), gastrointestinal pathology (4%), or unspecified (27%). Meta-analysis showed an overall rate of unexpected findings of 3.5% (95% CI 2.7-4.3; moderate certainty), and the sensitivity analysis showed similar results. Malignancy found in the appendix when treating suspected acute appendicitis was 1.0% (95% CI 0.8-1.3%; high certainty).

CONCLUSION

The rate of other histopathological findings in patients with suspected acute appendicitis was low and a malignancy in appendix was found in 1% of patients.

Varying negative appendectomy rates after laparoscopic appendectomy: a systematic review and meta-analysis

PURPOSE

Appendicitis is a common cause of acute abdominal pain, and treatment with laparoscopy has become increasingly common during the past two decades. Guidelines recommend that normal appendices are removed if operated for suspected acute appendicitis. It is unclear how many patients are affected by this recommendation. The aim of this study was to estimate the rate of negative appendectomies in patients undergoing laparoscopic surgery for suspected acute appendicitis.

METHODS

This study was reported following the PRISMA 2020 statement. A systematic search was conducted in PubMed and Embase for retrospective or prospective cohort studies (with n ≥ 100) including patients with suspected acute appendicitis. The primary outcome was the histopathologically confirmed negative appendectomy rate after a laparoscopic approach with a 95% confidence interval (CI). We performed subgroup analyses on geographical region, age, sex, and use of preoperative imaging or scoring systems. The risk of bias was assessed using the Newcastle-Ottawa Scale. Certainty of the evidence was assessed using GRADE.

RESULTS

In total, 74 studies were identified, summing up to 76,688 patients. The negative appendectomy rate varied from 0% to 46% in the included studies (interquartile range 4-20%). The meta-analysis estimated the negative appendectomy rate to be 13% (95% CI 12-14%) with large variations between the individual studies. Sensitivity analyses did not change the estimate. The certainty of evidence by GRADE was moderate due to inconsistency in point estimates.

CONCLUSION

The overall estimated negative appendectomy rate after laparoscopic surgery was 13% with moderate certainty of evidence. The negative appendectomy rate varied greatly between studies.

A systematic review and meta-regression for validation of the Alvarado score as a tool for predicting acute appendicitis

The Alvarado score (AS) has not been widely used for diagnosing acute appendicitis although it has shown to be a good predictor for diagnosing appendicitis. The aim was to perform a systematic review of the available literature and synthesize the evidence.

Methods

A systematic review was performed as per the PRISMA guidelines using search engines like Ovid, PubMed, and Google Scholar with predefined, strict inclusion and exclusion criteria. The quality assessment of included studies was performed using the QUADAS 2 tool. Summary statistics were performed for all variables. A linear regression model was performed between dependent and independent variables using STATA software. Heterogeneity testing showed significant heterogeneity within the included studies; hence, a forest plot with pooled estimates could not be constructed, and therefore a meta-regression was performed.

Results

Seventeen full-text articles met inclusion and exclusion criteria. Ten of which were identified as low-risk studies. Five studies were included in final data pooling with total patients being 2239 and mean age of 31.9 years. (1) Linear regression demonstrated an association between 'histological appendicitis' and 'AS 7-0' with patients receiving intervention, with a significant P value of less than 0.005. (2) Meta-regression demonstrated a positive coefficient (0.298), a positive Z score of 2.20 with a significant P value of 0.028 for patients with 'high AS' who received interventions that were significantly proven to be 'histologically appendicitis', indicating a cause-and-effect relationship.

Conclusion

High AS (7 and above) is a significant predictor of acute appendicitis. The authors recommend further prospective randomized clinical trials to establish a cause-and-effect relationship.

Periappendiceal fat-stranding models for discriminating between complicated and uncomplicated acute appendicitis: a diagnostic and validation study

BACKGROUND

Recent studies have reported promising outcomes of non-operative treatment for uncomplicated appendicitis; however, the preoperative prediction of complicated appendicitis is challenging. We developed models by incorporating fat stranding (FS), which is commonly observed in perforated appendicitis.

MATERIAL AND METHODS

We reviewed the data of 402 consecutive patients with confirmed acute appendicitis from our prospective registry. Multivariate logistic regression was performed to select clinical and radiographic factors predicting complicated acute appendicitis in our model 1 (involving backward elimination) and model 2 (involving stepwise selection). We compared c statistics among scoring systems developed by Bröker et al. (in J Surg Res 176(1):79-83. https://doi.org/10.1016/j.jss.2011.09.049 , 2012), Imaoka et al. (in World J Emerg Surg 11(1):1-5, 2016), Khan et al. (in Cureus. https://doi.org/1010.7759/cureus.4765 , 2019), Kim et al. (in Ann Coloproctol 31(5):192, 2015), Kang et al. (in Medicine 98(23): e15768, 2019), Atema et al. (in Br J Surg 102(8):979-990. https://doi.org/10.1002/bjs.9835 , 2015), Avanesov et al. (in Eur Radiol 28(9):3601-3610, 2018), and Kim et al. (in Abdom Radiol 46:1-12, 2020). Finally, we examined our models by performing the integrated discrimination improvement (IDI) test.

RESULTS

Among enrolled patients, 64 (15.9%) had complicated acute appendicitis. We developed new 10-point scoring models by including the following variables: C-reactive protein, neutrophil to lymphocyte ratio, and computed tomography features of FS, ascites, and appendicolith. A cutoff score of ≥ 6 exhibited a high sensitivity of 82.8% and a specificity of 82.8% for model 1 and 81.3% and 82.3% for model 2, respectively, with c statistics of 0.878 (model 1) and 0.879 (model 2). Compared with the model developed by Bröker et al. which included C-reactive protein and the abdominal pain duration (c statistic: 0.778), the models developed by Atema et al. (c statistic: 0.826, IDI: 5.92%, P = 0.0248), H.Y Kim et al. (c statistics: 0.838, IDI: 13.82%, P = 0.0248), and our two models (IDI: 18.29%, P < 0.0001) demonstrated a significantly higher diagnostic accuracy.

CONCLUSION

Our models and the scoring systems developed by Atema et al. and Kim et al. were validated to have a high diagnostic accuracy; moreover, our models included the lowest number of variables.