Pediatric Rectosigmoid Atypical Juvenile Polyps Presenting With Rectal Prolapse and Acute Bleeding: A Case Report and a Comprehensive Literature Review.

Rectosigmoid solitary juvenile polyps are benign lesions, relatively frequent in childhood. The clinical debut of a pediatric polyp with bleeding is relatively frequent, but there are very few reports of rectal prolapse of polyps. We present the case of a 7-year-old female patient with no previous history who presented with rectal prolapse of a polyp with acute bleeding. An urgent endoscopic examination was performed and 2 rectosigmoid polypoid lesions were found and resected. The anatomopathological study showed that these were 2 hamartomatous polyps with mild dysplasia. The patient is asymptomatic and is being followed up. The literature concerning rectal prolapse of polyps in the pediatric population is scarce. In a pediatric patient with a rectal prolapse, this entity should be considered in the differential diagnosis.

Utility of thiol/disulphide homeostasis as a biomarker for acute appendicitis: a systematic review and meta-analysis.

The aim of this study was to analyze the role of thiol/disulfide homeostasis (TDH) parameters as an indicator of oxidative stress in acute appendicitis (AA). PubMed, EMBASE, Web of Science, and Scopus databases were systematically searched. Studies reporting on TDH in AA (both complicated and uncomplicated cases) were included. The comparator group were healthy controls. The TDH domain was compared between the groups using anti-oxidant parameters, namely native thiol and total thiol levels, and native thiol/total thiol ratio; and oxidant parameters, namely disulfide level, disulfide/native thiol ratio, and disulfide/total thiol ratio. The statistical analysis was performed using a random-effects model. The methodological quality of the studies was assessed utilizing the Newcastle-Ottawa scale. Eleven studies with a total of 926 subjects, comprising 457 patients with uncomplicated appendicitis, 147 with complicated appendicitis, and 322 healthy controls were included. Our study demonstrated significantly increased oxidative stress in AA as compared to healthy controls in all TDH parameters and significantly lower total thiol levels in complicated AA as compared to uncomplicated AA. Due to a poor methodological quality in five out of eleven studies, future prospective studies with adequate power are essential to validate these observations and refine the diagnostic approaches to AA.

Explaining the colour of natural healthy gingiva.

To examine the differences between natural gingival colour in men and women. To determine the degree of predictability of changes in the gingival colour coordinates recorded for healthy gingiva, according to age, long-term medication, frequency of toothbrushing, and smoking habits. The CIELAB colour coordinates were recorded using a spectrophotometer for 360 Caucasian adult participants (aged 18-92 years), in three zones of the healthy attached gingiva of the maxillary central incisor. Regression models were created for each zone and each sex, taking the L*, a* and b* coordinates as dependent variables and age, frequency of toothbrushing, smoking habits (0-non-smoker; 1-smoker) and whether participants were taking long-term medication (0-no; 1-yes) as independent variables. The statistical analysis was conducted with SPSS version 26.0, using multiple regression models. Statistically significant differences between men and women were found only for colour coordinate b*, in all three zones. The only colour coordinate on which the predictor variables had a significant effect was the L* coordinate. In men, age and long-term medication had the greatest effect as predictors (maximum R2 = 0.149). In women, frequency of toothbrushing was the strongest predictor in the predictive models (maximum R2 = 0.099). The colour of gingiva in men contained a larger amount of blue, given that significantly lower values for colour coordinate b* were recorded in men than women, although this difference lacked clinical implications. For both sexes, the regression models produced had a modest predictive capacity. The L* coordinate was the dependent variable that showed the greatest predictability.

Three-dimensional representation of the Vita Toothguide 3D-Master: An in vivo clinical study.

STATEMENT OF PROBLEM: The Vita Toothguide 3D-Master (Vita Zahnfabrik) is considered the dental shade guide in which the three dimensions of color - lightness, hue, and chroma - are most well-ordered in the CIELAB color space. No research has yet explored how well the Vita Toothguide 3D-Master is ordered in the 3D color space by recording color coordinates in vivo. PURPOSE: To evaluate the spatial color distribution of the Vita Toothguide 3D-Master's lightness, chroma, and hue groups and its 26 physical shade tabs. MATERIALS AND METHODS: The dental color (L*, C*, h°, a*, and b* color coordinates) of a healthy maxillary central incisor was recorded for 1361 participants (aged between 18 and 89 years) using a Vita Easyshade Compact spectrophotometer (Vita Zahnfabrik). The R 2.7.2. statistics program was used to create the visual representations. RESULTS: The five lightness levels are those that are best distributed in the color space, in relation to the L* coordinates, followed by the chroma group and, finally, the hue group. The 5M1, 5M2, and 5M3 physical shade tabs are situated at a greater distance apart from the other tabs in the color space. CONCLUSIONS: The Vita Toothguide 3D-Master's 26 physical shade tabs are satisfactorily distributed in three-dimensional space, although strict mathematical criteria are not followed. The natural dental shades that fall lower on the lightness scale are the most poorly represented by the physical shade tabs. CLINICAL IMPLICATIONS: Darker teeth are poorly represented by the Vita Toothguide 3D-Master's physical shade tabs. The spatial distribution of dental shade guides needs to be improved to ensure they provide homogeneous coverage of the entire chromatic spectrum corresponding to natural teeth. This would help reduce the errors inherent to the subjective visual color selection process.

Sea-blue histiocytosis.

A 78-year-old woman with hypertrophic cardiomyopathy underwent a septal myomectomy and valve replacement. In the immediate postoperative period she developed shock of mixed etiology and died. At autopsy, hepatomegaly and splenomegaly were identified, with PAS and Giemsa positive intracellular ceroid granular deposits. Sea-blue histiocytosis is an extremely rare, chronic and benign deposit disease. It is characterized by hepatosplenomegaly, thrombocytopenia and lymphadenopathy. The presence of ceroid substance in granules in PAS and Giemsa stains should establish the diagnosis of suspicion.

Exosomes and the cardiovascular system: role in cardiovascular health and disease.

Exosomes, which are membrane-bound extracellular vesicles (EVs), are generated in the endosomal compartment of almost all eukaryotic cells. They are formed upon the fusion of multivesicular bodies and the plasma membrane and carry proteins, nucleic acids, lipids and other cellular constituents from their parent cells. Multiple factors influence their production including cell stress and injury, humoral factors, circulating toxins, and oxidative stress. They play an important role in intercellular communication, through their ability to transfer their cargo (proteins, lipids, RNAs) from one cell to another. Exosomes have been implicated in the pathophysiology of various diseases including cardiovascular disease (CVD), cancer, kidney disease, and inflammatory conditions. In addition, circulating exosomes may act as biomarkers for diagnostic and prognostic strategies for several pathological processes. In particular exosome-containing miRNAs have been suggested as biomarkers for the diagnosis and prognosis of myocardial injury, stroke and endothelial dysfunction. They may also have therapeutic potential, acting as vectors to deliver therapies in a targeted manner, such as the delivery of protective miRNAs. Transfection techniques are in development to load exosomes with desired cargo, such as proteins or miRNAs, to achieve up-regulation in the host cell or tissue. These advances in the field have the potential to assist in the detection and monitoring progress of a disease in patients during its early clinical stages, as well as targeted drug delivery.

Diagnostic performance of urinary 5-Hydroxyindoleacetic Acid in acute appendicitis: a systematic review and diagnostic test accuracy meta-analysis.

OBJECTIVES: This study aimed to analyze the diagnostic performance of urinary 5-Hydroxyindoleacetic Acid (5-HIAA) in acute appendicitis (AA). METHODS: This review was registered in PROSPERO (CRD42023399541). We included prospective or retrospective original clinical studies evaluating the diagnostic performance of 5-HIAA in AA. A search was conducted in PubMed, Web of Science, Scopus and OVID. Search terms and keywords were: (appendicitis OR acute appendicitis) AND (5-HIAA OR 5-Hydroxyindoleacetic acid OR serotonin metabolite). Two independent reviewers selected the articles and extracted relevant data. Methodological quality was assessed using the QUADAS2 index. A synthesis of the results, standardization of the metrics, and a random-effect meta-analysis were performed. Additionally, a coupled forest plot and a diagnostic test accuracy meta-analysis (DTA) were performed. RESULTS: Twelve studies with data from 1467 participants (724 patients with a confirmed diagnosis of AA and 743 controls) were included in this review. The random-effect meta-analysis of urinary 5-HIAA (AA vs controls) included 7 articles (352 AA and 258 controls) and resulted in a significant mean difference [95% CI] of 23.30 [15.82-30.77] µmol/L (p < 0.001). The DTA meta-analysis of urinary 5-HIAA included 8 articles and resulted in a pooled sensitivity [95% CI] of 68.6 [44.1-85.9]% and a pooled specificity [95% CI] of 82 [54.7-94.5]%. CONCLUSIONS: Although the evidence is heterogeneous and limited, urinary 5-HIAA emerges as a potential non-invasive diagnostic tool for AA. Urinary 5-HIAA does not seem to be a useful biomarker to distinguish between NCAA and CAA. Future prospective studies with a large sample size and a rigorous design are necessary to validate these findings. TRIAL REGISTRATION: PROSPERO (CRD42023399541).

Leucine-Rich Alpha-2-Glycoprotein as a non-invasive biomarker for pediatric acute appendicitis: a systematic review and meta-analysis.

The aim of this study was to analyze the diagnostic performance of Leucine-Rich Alpha-2-Glycoprotein (LRG1) in pediatric acute appendicitis (PAA). We conducted a systematic review of the literature in the main databases of medical bibliography. Two independent reviewers selected the articles and extracted relevant data. Methodological quality was assessed using the QUADAS2 index. A synthesis of the results, standardization of the metrics and 4 random-effect meta-analyses were performed. Eight studies with data from 712 participants (305 patients with confirmed diagnosis of PAA and 407 controls) were included in this review. The random-effect meta-analysis of serum LRG1 (PAA vs control) resulted in a significant mean difference (95% CI) of 46.76 µg/mL (29.26-64.26). The random-effect meta-analysis for unadjusted urinary LRG1 (PAA vs control) resulted in a significant mean difference (95% CI) of 0.61 µg/mL (0.30-0.93). The random-effect meta-analysis (PAA vs control) for urinary LRG1 adjusted for urinary creatinine resulted in a significant mean difference (95% CI) of 0.89 g/mol (0.11-1.66).   Conlusion: Urinary LRG1 emerges as a potential non-invasive biomarker for the diagnosis of PAA. On the other hand, due to the high between-study heterogeneity, the results on serum LRG1 should be interpreted with caution. The only study that analyzed salivary LRG1 showed promising results. Further prospective studies are needed to confirm these findings. What is Known: • Pediatric acute appendicitis continues to be a pathology with a high rate of diagnostic error. • Invasive tests, although useful, are a source of stress for patients and their parents. What is New: • LRG1 emerges as a promising urinary and salivary biomarker for the noninvasive diagnosis of pediatric acute appendicitis.

Volumetric analysis on the use of customized healing abutments with or without connective tissue graft at flapless maxillary immediate implant placement: A randomized clinical trial.

OBJECTIVES: To evaluate buccal volume change after using a customized healing abutment with or without connective tissue grafts (CTG) in flapless maxillary immediate implant placement (IIP). MATERIALS AND METHODS: The present study was designed as a randomized clinical trial (RCT). Patients treated with flapless maxillary IIP were allocated into two groups, both receiving a customized healing abutment, and additionally, the test group received a CTG. A cone-beam computerized tomography (CBCT) allowed to access the initial buccal bone thickness (BT). Digital impressions were taken prior to extractions (T0), 1 month (T1), 4 months (T2), and 12 months (T3) after implant insertion and superimposed with computer software allowing to compute variables related to buccal volume variation (BVv) and total volume variation (TVv) (ClinicalTrials.gov: NCT05060055). RESULTS: Thirty-two patients (mean age 48 ± 11 years), sixteen in each group, were evaluated after a 12-month period. After 1 year of treatment, no significant differences were found between groups, although in participants with BT ≤1 mm, control and test groups showed a BVv of -14.18 ± 3.49% and -8.30 ± 3.78%, respectively (p = .033). Regarding mucosa height variation variables, the control group showed approximately the triple vertical recession in both papillae. CONCLUSIONS: The placement of a CTG was not capable of completely maintaining the initial peri-implant tissue architecture, although in thin-bone phenotypes, less dimensional changes are expected when a CTG was used.

Glans Penis Ischemia after Circumcision in a 15-Year-Old Patient Managed with Intravenous Pentoxifylline: A Case Report and a Diagnostic-Therapeutic Guideline Proposal.

Glans ischemia is an extremely infrequent complication characterized by a total or partial compromise in the penile arterial perfusion. A 15-year-old male patient suffered an episode of ischemia in the glans penis post-circumcision 24 h after surgery. Intravenous treatment with continuous perfusion of pentoxifylline was started for 4 days, with favorable evolution. Complete resolution was observed with no sequelae. There is no consensus on the best therapeutic management. The favorable evolution reported in most of the cases despite different therapeutic approaches leads us to think that the role of the treatments proposed so far is probably less than we believe. Additionally, we present a proposal for a diagnostic and therapeutic guide for this entity. Although the evidence in the literature is scarce and this guideline should be interpreted with caution, we believe that it can constitute a support resource for cases similar to ours.

The BIDIAP index: a clinical, analytical and ultrasonographic score for the diagnosis of acute appendicitis in children.

BACKGROUND: Pediatric acute appendicitis (PAA) continues to be a diagnostic challenge today. The diagnostic performance of classical indices is only moderate, especially in pediatric population. This study aimed to define a clinical, radiological and analytical index for the diagnosis of PAA. MATERIALS AND METHODS: This prospective study included 151 patients divided into two groups: (1) 53 patients with non-surgical abdominal pain (NSAP) and (2) 98 patients with a confirmed PAA. Sociodemographic and clinical characteristics were compared between groups using the Mann-Whitney U test and the Fisher exact test. To identify the predictors of PAA, we performed a multivariable logistic regression using a forward stepwise analysis and we assigned multiples of integer values to the selected variables. The diagnostic performance of the index was assessed by calculating the area under the receiver operating characteristic curve. Intra-cohort calibration was assessed with the Hosmer-Lemeshow test. RESULTS: We developed the BIDIAP index (BIomarkers for the DIagnosis of Appendicitis in Pediatrics), which included three variables that independently predicted higher odds of PAA: appendiceal caliber (≥ 6.9 mm), systemic immune-inflammation index (≥ 890) and peritoneal irritation, which scored 4, 3 and 2 points, respectively. Mean (SD) score of the participants was 2.38 (2.06) in group 1 and 7.89 (1.50) in group 2. The area under the ROC was 0.97 (95% CI 0.95-0.99). The cut-off point was established at 4 points, resulting in a sensitivity of 98.98% and a specificity of 77.78%. CONCLUSIONS: The BIDIAP index has an exceptional diagnostic performance in PAA. The importance of these results lies in its novelty and in the simplicity of the index. Although external validation will be necessary, initial results look promising.

Flow cytometric characterization of cecal appendix lymphocyte subpopulations in children: a pilot study.

INTRODUCTION: Scientific literature regarding the characterization of lymphocyte subpopulations of the cecal appendix is sparse, with few precedents limited to immunohistochemical techniques. METHODS: We conducted a prospective pilot study to characterize lymphocyte subpopulations of the cecal appendix in children. Participants were divided into three groups: (1) patients without histological acute appendiceal inflammation, (2) patients with histological uncomplicated acute appendicitis, and (3) patients with histological complicated acute appendicitis (gangrenous, perforated). A fresh sample of the base of the appendix was taken from all patients and a flow cytometric study was performed. Quantitative variables were compared using Kruskal-Wallis test and Mann-Whitney U test. RESULTS: This study included 57 patients divided into Group 1 (n = 5), Group 2 (n = 37), and Group 3 (n = 15). Median values (IQR) of the percentage of B-lymphocytes were 67.8 [66.8-68.1] in group 1, 61.15 [53.74-66.4] in group 2, and 52.1 [33-62.02] in group 3 (p = 0.02). Median values (IQR) of the percentage of NK-lymphocytes were 0.26 [0.2-0.3] in group 1, 0.55 [0.37-0.66] in group 2, and 0.84 [0.35-1.45] in group 3 (p = 0.008). Median values (IQR) of the percentage of T-lymphocytes were 31.9 [31.7-33.1] in group 1, 37.68 [32.15-45.69] in group 2, and 46.9 [37.03-67] in group 3 (p = 0.02). Pair comparisons of groups 2 and 3 also showed significant differences in the percentage of B lymphocytes (p = 0.03) and NK-lymphocytes (p = 0.02). CONCLUSIONS: Significant differences in lymphocyte subpopulations were identified according to the histologic grade of the cecal appendix. More specifically, a lower percentage of B-lymphocytes and a higher percentage of T- and NK-lymphocytes were observed in cases of acute appendicitis. These findings must be confirmed and their etiopathogenic, diagnostic, and prognostic implications elucidated in future studies with larger sample sizes.

Use of bioinformatic strategies as a predictive tool in implant-supported oral rehabilitation: A scoping review.

STATEMENT OF PROBLEM: The use of bioinformatic strategies is growing in dental implant protocols. The current expansion of Omics sciences and artificial intelligence (AI) algorithms in implant dentistry applications have not been documented and analyzed as a predictive tool for the success of dental implants. PURPOSE: The purpose of this scoping review was to analyze how artificial intelligence algorithms and Omics technologies are being applied in the field of oral implantology as a predictive tool for dental implant success. MATERIAL AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist was followed. A search strategy was created at PubMed and Web of Science to answer the question "How is bioinformatics being applied in the area of oral implantology as a predictive tool for implant success?" RESULTS: Thirteen articles were included in this review. Only 3 applied bioinformatic models combining AI algorithms and Omics technologies. These studies highlighted 2 key points for the creation of precision medicine: deep population phenotyping and the integration of Omics sciences in clinical protocols. Most of the studies identified applied AI only in the identification and classification of implant systems, quantification of peri-implant bone loss, and 3-dimensional bone analysis, planning implant placement. CONCLUSIONS: The conventional criteria currently used as a technique for the diagnosis and monitoring of dental implants are insufficient and have low accuracy. Models that apply AI algorithms combined with precision methodologies-biomarkers-are extremely useful in the creation of precision medicine, allowing medical dentists to forecast the success of the implant. Tools that integrate the different types of data, including imaging, molecular, risk factor, and implant characteristics, are needed to make a more accurate and personalized prediction of implant success.

Peri-implant diseases diagnosis, prognosis and dental implant monitoring: a narrative review of novel strategies and clinical impact.

BACKGROUND: The diagnosis of peri-implantar and periodontal relies mainly on a set of clinical measures and the evaluation of radiographic images. However, these clinical settings alone are not sufficient to determine, much less predict, periimplant bone loss or future implant failure. Early diagnosis of periimplant diseases and its rate of progress may be possible through biomarkers assessment. Once identified, biomarkers of peri-implant and periodontal tissue destruction may alert the clinicians before clinical signs show up. Therefore, it is important to consider developing chair-side diagnostic tests with specificity for a particular biomarker, indicating the current activity of the disease. METHODS: A search strategy was created at Pubmed and Web of Science to answer the question: "How the molecular point-of-care tests currently available can help in the early detection of peri-implant diseases and throws light on improvements in point of care diagnostics devices?" RESULTS: The PerioSafe® PRO DRS (dentognostics GmbH, Jena) and ImplantSafe® DR (dentognostics GmbH, Jena ORALyzer® test kits, already used clinically, can be a helpful adjunct tool in enhancing the diagnosis and prognosis of periodontal/peri-implantar diseases. With the advances of sensor technology, the biosensors can perform daily monitoring of dental implants or periodontal diseases, making contributions to personal healthcare and improve the current status quo of health management and human health. CONCLUSIONS: Based on the findings, more emphasis is given to the role of biomarkers in diagnosing and monitoring periodontal and peri-implant diseases. By combining these strategies with traditional protocols, professionals could increase the accuracy of early detection of peri-implant and periodontal diseases, predicting disease progression, and monitoring of treatment outcomes.

Giant Perineal Plexiform Neurofibroma in an 8-Year-Old African Male.

The perineal presentation of plexiform neurofibroma is exceptional, with only two cases reported to date.We present an 8-year-old African male with a large perineal tumor of years of evolution. He had no associated symptoms. Café au lait stains were observed on examination, without other findings of relevance. The patient had no preoperative radiological studies. Partial excision of the lesion was performed. Histopathological study of the specimen revealed a plexiform neurofibroma.The lack of diagnostic suspicion due to the atypical nature of the location, the anatomical complexity of surgical resection and the potential urological and rectal involvement make this lesion a diagnostic-therapeutic challenge. Among the differential diagnoses, schwannoma, congenital lipoma, hamartoma and lipoblastoma should be considered.

Extensive Keloid and Hypertrophic Mixed Scarring Pattern in Ear Lobes of a 14-Year-Old African Female: A Case Report.

Background Massive earlobe scarring/keloid formation can occur after ear piercing in individuals of African descent. Case report: A 14-year-old African girl with pierced ears in childhood presented with two progressively growing and disfiguring tumors on both earlobes. The maximum diameter of each lesion was 5.5 centimeters, and the weight of each lesion was approximately 20 grams. Histologically, there was a mixed pattern of keloid and hypertrophic scarring. Discussion: Massive keloids can occur after ear piercing in childhood. It is unclear why some individuals develop these massive keloids.

Unilateral Anophthalmia and Congenital Frontal Cranioschisis Associated with Extradural Neuroglial Heterotopia: new Insights into a Possible New Malformative Spectrum.

Background: Neuroglial heterotopia, characterized by mature -neuroglial tissue outside the central nervous system, has not been previously associated with cranioschisis. Case Report: A 4-year-old female patient, with left congenital anophthalmia, had a nasofrontal neuroglial heterotopia protruding through an ossification defect. Discussion: Nasofrontal cranioschisis may be associated with neuroglial heterotopias. The combination of anophthalmia and neuroglial heterotopia, previously described only once in the literature, may be part of a broader malformation spectrum that has not been properly characterized to date.

Diaphanospondylodysostosis: Full Case Report with Novel Pathogenic BMPER Mutation.

Diaphanospondylodysostosis is an extremely rare, recessively inherited, perinatal lethal skeletal disorder associated with BMPER gene mutations. Clinically it is characterized by defects in costovertebral ossification, absent ribs, hypertelorism, short nose with depressed nasal bridge, low-set ears, and short neck. At the extraosseous level, the most frequent pathologic finding is nephroblastomatosis with multicystic kidneys. We present the case of a child of non-consanguineous parents who died at 2 months of age in our center. Autopsy showed a marked costovertebral ossification defect, perilobar nephrogenic rests and loss of white matter with periventricular leukomalacia. After genetic study, the diagnosis of diaphanospondylodysostosis was confirmed. A previously undescribed germinal mutation in the BMPER gene (c.576 + 2dupT) was found.

Cigarette Smoke Directly Promotes Pulmonary Arterial Remodeling and Kv7.4 Channel Dysfunction.

Rationale: Cigarette smoke is considered the chief leading cause of chronic obstructive pulmonary disease (COPD). Its impact on the progressive deterioration of airways has been extensively studied, but its direct effects on the pulmonary vasculature are less known. Objectives: To prove that pulmonary arterial remodeling in patients with COPD is not just a consequence of alveolar hypoxia but also due to the direct effects of cigarette smoke on the pulmonary vascular bed. Methods: We have used different molecular and cell biology approaches, as well as traction force microscopy, wire myography, and patch-clamp techniques in human cells and freshly isolated pulmonary arteries. In addition, we relied on in vivo models and human samples to analyze the effects of cigarette smoke on pulmonary vascular tone alterations. Measurements and Main Results: Cigarette smoke extract exposure directly promoted a hypertrophic, senescent phenotype that in turn contributed, through the secretion of inflammatory molecules, to an increase in the proliferative potential of nonexposed cells. Interestingly, these effects were significantly reversed by antioxidants. Furthermore, cigarette smoke extract affected cell contractility and dysregulated the expression and activity of the voltage-gated K+ channel Kv7.4. This contributed to the impairment of vasoconstriction and vasodilation responses. Most importantly, the levels of this channel were diminished in the lungs of smoke-exposed mice, smokers, and patients with COPD. Conclusions: Cigarette smoke directly contributes to pulmonary arterial remodeling through increased cell senescence, as well as vascular tone alterations because of diminished levels and function in the Kv7.4 channel. Strategies targeting these pathways may lead to novel therapies for COPD.

Discriminatory capacity of serum total bilirubin between complicated and uncomplicated acute appendicitis in children: a systematic review and a diagnostic test accuracy meta-analysis.

This study aimed to examine the ability of serum total bilirubin (STB) to discriminate between complicated and uncomplicated paediatric acute appendicitis (PAA). We conducted a systematic review of the literature that involved an extensive search in the main databases of medical bibliography (Medline, PubMed, Web of Science, OVID, Scopus, Cochrane Library). Two independent reviewers selected the relevant articles based on the previously defined inclusion and exclusion criteria. Methodological quality of the selected articles was assessed using the QUADAS2 index. Data extraction was performed by two independent reviewers. A synthesis of the results, a standardization of the metrics and a random-effect meta-analysis were performed. Between-study heterogeneity was assessed in subgroup analysis by study design. In addition, a diagnostic test accuracy (DTA) meta-analysis was performed. This review included 8 studies with data from 3634 participants aged between 0 and 18 years (2230 with uncomplicated PAA and 1404 with complicated PAA). The random-effects meta-analysis showed significantly higher mean STB in the complicated PAA group than in the uncomplicated PAA group (difference = 0.27; 95% CI 0.06-0.48) and high heterogeneity (I2 = 96%). In subgroup analyses by study design, the difference remained significant in prospective studies. The DTA meta-analysis resulted in an AUC of 0.83 (95% CI 0.79-0.86) and pooled sensitivity and specificity of 68.53% (95% CI 48.35%-83.51%) and 81.12% (95% CI 67.76%-89.78%), respectively. Mean values of STB are higher in children with complicated than uncomplicated acute appendicitis, and the diagnostic yield of STB seems to be high. Due to the high heterogeneity between studies, these results must be interpreted with caution.