Compilation of Evidence Supporting the Role of a T Helper 2 Reaction in the Pathogenesis of Acute Appendicitis.

Despite being the most common abdominal surgical emergency, the cause of acute appendicitis (AA) remains unclear, since in recent decades little progress has been made regarding its etiology. Obstruction of the appendicular lumen has been traditionally presented as the initial event of AA; however, this is often the exception rather than the rule, as experimental data suggest that obstruction is not an important causal factor in AA, despite possibly occurring as a consequence of the inflammatory process. Type I hypersensitivity reaction has been extensively studied, involving Th2 lymphocytes, and cytokines such as IL-4, IL-5, IL-9 and IL-13, which have well-defined functions, such as a positive-feedback effect on Th0 for differentiating into Th2 cells, recruitment of eosinophils and the release of eosinophilic proteins and the production of IgE with the activation of mast cells, with the release of proteins from their granules. Cytotoxic activity and tissue damage will be responsible for the clinical manifestation of the allergy. AA histological features are similar to those found in allergic reactions like asthma. The intestine has all the components for an allergic immune response. It has contact with hundreds of antigens daily, most of them harmless, but some can potentially induce an allergic response. In recent years, researchers have been trying to assess if allergy is a component of AA, with their latest advances in the understanding of AA as a Th2 reaction shown by the authors of this article.

Tryptase in Acute Appendicitis: Unveiling Allergic Connections through Compelling Evidence.

The aetiology of acute appendicitis (AA), the most frequent abdominal surgical emergency, is still unclarified. Recent epidemiologic, clinical and laboratorial data point to an allergic component in the pathophysiology of AA. Mastocytes participate in the Th2 immune response, releasing inflammatory mediators from their granules upon stimulation by IgE-specific antigens. Among the well-known mediators are histamine, serotonin and tryptase, which are responsible for the clinical manifestations of allergies. We conducted a prospective single-centre study to measure histamine and serotonin (commercial ELISA kit) and tryptase (ImmunoCAP System) concentrations in appendicular lavage fluid (ALF) and serum. Consecutive patients presenting to the emergency department with a clinical diagnosis of AA were enrolled: 22 patients with phlegmonous AA and 24 with gangrenous AA The control group was composed of 14 patients referred for colectomy for colon malignancy. Appendectomy was performed during colectomy. Tryptase levels were strikingly different between histological groups, both in ALF and serum (p < 0.001); ALF levels were higher than serum levels. Tryptase concentrations in ALF were 109 times higher in phlegmonous AA (APA) (796.8 (194.1-980.5) pg/mL) and 114 times higher in gangrenous AA (AGA) (837.4 (272.6-1075.1) pg/mL) than in the control group (7.3 (4.5-10.3) pg/mL. For the diagnosis of AA, the discriminative power of serum tryptase concentration was good (AUC = 0.825), but discriminative power was weak (AUC = 0.559) for the differential diagnosis between APA and AGA. Mastocytes are involved in AA during clinical presentations of both phlegmonous and gangrenous appendicitis, and no significant differences in concentration were found. No differences were found in serum and ALF concentrations of histamine and serotonin between histological groups. Due to their short half-lives, these might have elapsed by the time the samples were collected. In future research, these determinations should be made immediately after appendectomy. Our findings confirm the hypersensitivity type I reaction as an event occurring in the pathogenesis of AA: tryptase levels in ALF and serum were higher among patients with AA when compared to the control group, which is in line with a Th2 immune response and supports the concept of the presence of an allergic reaction in the pathogenesis of acute appendicitis. Our results, if confirmed, may have clinical implications for the treatment of AA.

Outcome of Laparoscopic Versus Open Appendectomy for Acute Appendicitis-Results of a Propensity Score Matching Analysis of 542 Patients and Consequences for the Military Surgeon.

INTRODUCTION: Appendectomy is the treatment of choice for acute appendicitis. The procedure can be performed open or laparoscopically. However, laparoscopy is not available on military missions abroad. It is unclear whether treatment outcomes differ between the two surgical approaches. MATERIALS AND METHODS: Treatment data of all patients undergoing open and laparoscopic appendectomies in the German Armed Forces Hospital of Ulm from 2013 to 2017 were collected retrospectively. A propensity score matching analysis was performed to minimize the influence of potential confounders and to assess the influence of surgical approach on outcome (reoperations, superficial and deep surgical infections, length of postoperative ileus, need for intravenous analgesics, and operative time). RESULTS: A total of 542 patients with complete datasets were included in the propensity score matching analysis, among these 64 with open and 478 laparoscopic procedures. There were no statistically significant differences between open and laparoscopic surgeries with respect to all outcome variables, with the exception of a 25-minute prolonged operative time for the open approach. CONCLUSIONS: Open appendectomy can be considered equivalent in outcome to the laparoscopic procedure and thus can be performed on military missions abroad without compromising outcome. Military surgeons must continue to be trained and confident in open appendectomy.

Surgical Outcomes and Quality of Care Among Adult Appendicitis Patients: A Comparative Study of Tertiary Care Hospitals and Regional Hospitals.

BACKGROUND: Acute appendicitis is one of the most common abdominal emergencies, with management approaches that vary depending on the available resources and setting. However, there is a lack of studies on the differences of surgical outcomes and quality of care between tertiary care hospitals and regional hospitals. METHODS: This multicenter retrospective study included 2158 consecutive adult patients between January 2014 and June 2018 at three hospitals. The patient cohort was divided into regional hospital group (N = 1223) and tertiary care hospital group (N = 935). Baseline characteristics and perioperative outcomes were compared, and factors associated with surgical delay and postoperative complication were investigated. RESULTS: Patients in tertiary care hospital group had longer surgical waiting time (17.3 vs. 12.0 h, p < 0.001), higher risks of surgical delay exceeding 24 h (OR = 2.94, 95% CI 2.17-4.01, p < 0.001), longer operation time (64 vs. 50 min, p < 0.001), more appendix perforation (22.4 vs. 13.3%, p < 0.001), and higher hospital cost compared with regional hospital group. In multivariate analysis, factors associated with surgical delay were tertiary care hospital (OR = 2.94, 95% CI 2.18-4.01, p < 0.001) and delay diagnosis (OR = 18.7, 95% CI 11.7-30.1, p < 0.001), while those associated with postoperative complications were older age (OR = 1.02, 95% CI 1.00-1.04, p = 0.013), male sex (OR = 2.38, 95% CI 1.11-5.52, p = 0.031), surgical delay (OR = 2.99, 95% CI 1.30-6.47, p = 0.007), and appendix perforation (OR = 5.61, 95% CI 2.72-11.85, p < 0.001). CONCLUSIONS: Patients at tertiary care hospitals had longer waiting time, more surgical delays, and appendix perforations, and these were risk factors of postoperative complications. Establishing an effective referral system to redirect appendicitis patients with less complex medical histories from tertiary care hospitals to regional hospitals may enhance the quality of patient care and outcomes, while also reducing medical costs.

Artificial intelligence differentiates abdominal Henoch-Schönlein purpura from acute appendicitis in children.

OBJECTIVE: This study aims to construct an artificial intelligence (AI) model capable of effectively discriminating between abdominal Henoch-Schönlein purpura (AHSP) and acute appendicitis (AA) in pediatric patients. METHODS: A total of 6965 participants, comprising 2201 individuals with AHSP and 4764 patients with AA, were enrolled in the study. Additionally, 53 laboratory indicators were taken into consideration. Five distinct artificial intelligence (AI) models were developed employing machine learning algorithms, namely XGBoost, AdaBoost, Gaussian Naïve Bayes (GNB), MLPClassifier (MLP), and support vector machine (SVM). The performance of these prediction models was assessed through receiver operating characteristic (ROC) curve analysis, calibration curve assessment, and decision curve analysis (DCA). RESULTS: We identified 32 discriminative indicators (p < .05) between AHSP and AA. Five indicators, namely the lymphocyte ratio (LYMPH ratio), eosinophil ratio (EO ratio), eosinophil count (EO count), neutrophil ratio (NEUT ratio), and C-reactive protein (CRP), exhibited strong performance in distinguishing AHSP from AA (AUC ≥ 0.80). Among the various prediction models, the XGBoost model displayed superior performance evidenced by the highest AUC (XGBoost = 0.895, other models < 0.89), accuracy (XGBoost = 0.824, other models < 0.81), and Kappa value (XGBoost = 0.621, other models < 0.60) in the validation set. After optimization, the XGBoost model demonstrated remarkable diagnostic performance for AHSP and AA (AUC > 0.95). Both the calibration curve and decision curve analysis suggested the promising clinical utility and net benefits of the XGBoost model. CONCLUSION: The AI-based machine learning model exhibits high prediction accuracy and can differentiate AHSP and AA from a data-driven perspective.

Appendiceal stump closure in laparoscopic appendectomy: one endoloop vs. two endoloops vs. two endoclips-does it matter?

PURPOSE: Appendiceal stump leak rate after laparoscopic appendectomy is extremely low. Various methods are used to close the appendiceal stump. This study aimed to compare the outcome of three appendiceal stump closure methods. METHODS: A retrospective study comparing stump closure methods and postoperative outcomes was conducted from January 2018 to June 2020. Patient data included demographics, pre-operative data, surgical technique, findings, and postoperative complications. RESULTS: Out of 1021 appendectomy patients, 733 underwent laparoscopic appendectomy for acute appendicitis utilizing one of the three compared appendiceal stump closure methods. Consequently, 360 appendixes were ligated with one endoloop (1EL group), 300 appendixes had two endoloops (2EL group), and 73 appendixes were ligated with two endoclips (2EC group). All groups used a LigaSure for resection. The rate of postoperative intra-abdominal abscess was 1% (4 patients) in 1EL group vs. 1% (3 patients) in 2EL group vs. none in 2EC group (p = 0.43). There were no reported appendiceal stump leaks. Overall complication rates were 4% (14 patients), 3% (9 patients), and 0 (p = 0.15), and the mean operative length was 43 ± 21, 54 ± 22, and 43 ± 20 mins for the 1EL, 2EL, and 2EC, respectively (p < 0.01). Average cost of one endoloop is 110$, and one endoclip cartridge is 180$. CONCLUSIONS: None of the methods were found clinically superior over the others. Considering the low and mild complication rate, it appears reasonable to prefer one method simply by cost. The use of a single endoloop may result in substantial cost reduction. Medical centers may advise surgeons to use a single-endoloop technique.

Low-Impact Laparoscopy vs Conventional Laparoscopy for Appendectomy: A Prospective Randomized Trial.

BACKGROUND: Low-impact laparoscopy (LIL), combining low-pressure insufflation and microlaparoscopy, is a surgical technique that is still not widely used and that has never been evaluated for the management of acute appendicitis. The aim of this study is to assess the feasibility of an LIL protocol, to compare postoperative pain, average length of stay, and in-hospital use of analgesics by patients who underwent appendectomy according to a conventional laparoscopy or an LIL protocol. STUDY DESIGN: Patients presenting with acute uncomplicated appendicitis who were operated on between January 1, 2021, and July 10, 2022, were included in this double-blind, single-center, prospective study. They were preoperatively randomly assigned to a group undergoing conventional laparoscopy, ie with an insufflation pressure of 12 mmHg and conventional instrumentation, and an LIL group, with an insufflation pressure of 7 mmHg and microlaparoscopic instrumentation. RESULTS: Fifty patients were included in this study, 24 in the LIL group and 26 in the conventional group. There were no statistically significant differences between the 2 patient groups, including weight and surgical history. The postoperative complication rate was comparable between the 2 groups (p = 0.81). Pain was reported as significantly lower according to the visual analog scale 2 hours after surgery among the LIL group (p = 0.019). For patients who underwent surgery according to the LIL protocol, the study confirms a statistically significant difference for theoretical and actual length of stay, ie -0.77 days and -0.59 days, respectively (p < 0.001 and p = 0.03). In-hospital use of analgesics was comparable between both groups. CONCLUSIONS: In uncomplicated acute appendicitis, the LIL protocol could reduce postoperative pain and average length of stay compared to conventional laparoscopic appendectomy.

Clinical characteristics of SARS-CoV-2 vaccine-related acute appendicitis.

BACKGROUND: In a large nationwide mass vaccination setting, the SARS-CoV-2 vaccine was recently linked to myocarditis, lymphadenopathy, herpes zoster infection and appendicitis. We aimed to examine the characteristics and management of SARS-CoV-2 vaccine-related acute appendicitis. METHODS: We performed a retrospective cohort study in a large tertiary medical centre in Israel. All patients presenting with acute appendicitis within 21 days of receiving their SARS-CoV-2 vaccination (PCVAA group) were compared with patients who presented with acute appendicitis not related to the vaccination (N-PCVAA group). RESULTS: We reviewed the records of 421 patients with acute appendicitis from December 2020 to September 2021; 38 (9%) patients presented with acute appendicitis within 21 days of receiving their SARS-CoV-2 vaccination. Patients in the PCVAA group were older than those in the N-PCVAA group (mean 41 ± 19 yr v. 33 ± 15 yr, respectively, p = 0.008), with male predominance. More patients were managed nonsurgically during the pandemic than before the pandemic (24% v. 18%, p = 0.03). CONCLUSION: With the exception of older age, the clinical characteristics of patients presenting with acute appendicitis within 21 days of receiving the SARS-CoV-2 vaccination did not differ from those of patients who presented with acute appendicitis not related to the vaccination. This finding suggests that vaccine-related acute appendicitis is similar to "classic" acute appendicitis.

Impacts of short-term air pollution exposure on appendicitis admissions: Evidence from one of the most polluted cities in mainland China.

Background: Emerging evidence indicates that air pollutants contribute to the development and progression of gastrointestinal diseases. However, there is scarce evidence of an association with appendicitis in mainland China. Methods: In this study, Linfen city, one of the most polluted cities in mainland China, was selected as the study site to explore whether air pollutants could affect appendicitis admissions and to identify susceptible populations. Daily data on appendicitis admissions and three principal air pollutants, including inhalable particulate matter (PM10), nitrogen dioxide (NO2), and sulfur dioxide (SO2) were collected in Linfen, China. The impacts of air pollutants on appendicitis were studied by using a generalized additive model (GAM) combined with the quasi-Poisson function. Stratified analyses were also performed by sex, age, and season. Results: We observed a positive association between air pollution and appendicitis admissions. For a 10 µg/m3 increase in pollutants at lag01, the corresponding relative risks (RRs) and 95% confidence intervals (95% CIs) were 1.0179 (1.0129-1.0230) for PM10, 1.0236 (1.0184-1.0288) for SO2, and 1.0979 (1.0704-1.1262) for NO2. Males and people aged 21-39 years were more susceptible to air pollutants. Regarding seasons, the effects seemed to be stronger during the cold season, but there was no statistically significant difference between the seasonal groups. Conclusions: Our findings indicated that short-term air pollution exposure was significantly correlated with appendicitis admissions, and active air pollution interventions should be implemented to reduce appendicitis hospitalizations, especially for males and people aged 21-39 years.

Open versus laparoscopic appendectomy for acute appendicitis in pregnancy: a population-based study.

BACKGROUND: Laparoscopic appendectomy (LA) is the standard treatment for acute appendicitis (AA) in general population. However, the safety of LA during pregnancy has remained a matter of debate. The purpose of this study was to compare surgical and obstetrical outcomes in pregnant women who underwent LA vs. open appendectomy (OA) for AA. We hypothesized that LA results in improved surgical and obstetric outcomes during pregnancy. METHODS: Using a nationwide claim-based database in Estonia, a retrospective review of all cases of pregnant women undergoing OA or LA for AA from 2010 to 2020 was performed. Patient characteristics, surgical and obstetrical outcomes were analyzed. Primary outcomes were preterm delivery, fetal loss and perinatal mortality. Secondary outcomes included operative time, hospital length of stay (HLOS) and 30-day postoperative complications. RESULTS: Overall, 102 patients were included of whom 68 (67%) underwent OA and 34 patients (33%) LA, respectively. Patients in LA cohort had a significantly shorter length of pregnancy in terms of gestational weeks when compared to OA cohort (12 weeks versus 17 weeks, p = 0.002). Most of the patients in their 3rd trimester pregnancy were subjected to OA. Operative time in LA cohort was shorter than in OA cohort (34 min. versus 44 min., p = 0.038). HLOS in LA cohort was shorter than in OA cohort (2.1 days versus 2.9 days, p = 0.016). There were no differences between OA and LA cohorts in terms of surgical complications or obstetrical outcomes. CONCLUSIONS: Laparoscopic appendectomy for acute appendicitis was associated with a significantly shorter operative time and a shorter hospital length of stay while open and laparoscopic appendectomy cohorts experienced comparable obstetrical outcomes. Our findings support the laparoscopic approach for acute appendicitis in pregnancy.

Has the Covid-19 Pandemic increased the complication rate in patients with acute appendicitis?

AIM: The aim of this study is to compare the numbers of patients, clinical outcomes, and complication rates of acute appendicitis before and after COVID-19 pandemic in our clinic. MATERIAL AND METHOD: This is a retrospective clinical study. Patients of 19 to 88 years of age that underwent emergency surgery with the diagnosis of acute appendicitis at Ankara City Hospital Department of General Surgery between 11 December 2019 and 11 June 2020 were included. The first case of COVID-19 in Turkey was announced on 11 March 2020. We studied the demographics, surgical procedures, and complication rates in 3 months periods before and after the first case was announced. RESULTS: A total number of 462 patients were analyzed between the ages of 19-88, 184 of which (39.8%) were females and 278 were males (60.2%). 253 of these patients were diagnosed with AA and underwent surgery before March 11 whereas 209 patients were diagnosed and treated after March 11. DISCUSSION: There was no statistical difference between the two groups in terms of complication rates before and after the pandemic. Although the rate of open appendectomy was increased after the pandemic, no statistical difference has been found. CONCLUSION: No change was observed in terms of hospital admissions, methods of treatment, complication rates, length of stay before and after the COVID-19 pandemic. KEY WORDS: Acute Appendicitis, Appendectomy, COVID-19.

Diarrhoea-causing microorganisms are rare in adult patients undergoing diagnostic laparoscopy for suspected appendicitis: a prospective observational cohort study.

We investigated if diarrhoea-causing bacteria, including Yersinia species, could mimic the symptoms of appendicitis and lead to surgery. This prospective observational cohort study (NCT03349814) included adult patients undergoing surgery for suspected appendicitis. Rectal swabs were analysed with polymerase chain reaction (PCR) for Yersinia, Campylobacter, Salmonella, Shigella and Aeromonas spp. Blood samples were analysed routinely and with an in-house ELISA serological test for Yersinia enterocolitica antibodies. We compared patients without appendicitis and patients with appendicitis confirmed by histopathology. The outcomes included PCR-confirmed infection with Yersinia spp., serologic-confirmed infection with Y. enterocolitica, PCR-confirmed infection with other diarrhoea-causing bacteria and Enterobius vermicularis confirmed by histopathology. A total of 224 patients were included, 51 without and 173 with appendicitis, and followed for 10 days. PCR-confirmed infection with Yersinia spp. was found in one patient (2%) without appendicitis and no patients (0%) with appendicitis (p = 0.23). Serology was positive for Y. enterocolitica for the same patient without appendicitis and two patients with appendicitis (p = 0.54). Campylobacter spp. were detected in 4% vs 1% (p = 0.13) of patients without and with appendicitis, respectively. Infection with Yersinia spp. and other diarrhoea-causing microorganisms in adult patients undergoing surgery for suspected appendicitis was rare.

Maternal Smoking During Pregnancy and Risk of Appendicitis in the Offspring.

BACKGROUND: Existing evidence on the link between smoking and appendicitis is scarce and ambiguous. We therefore conducted a population-based cohort study in Denmark to investigate whether smoking during pregnancy is associated with an increased risk of appendicitis in offspring. METHODS: We used the Danish Birth Registry to include all singletons born during 1991-2017 and to identify maternal smoking status during pregnancy. We followed the children from birth until date of appendicitis, emigration, death, or administrative end of study (31 December 2018), whichever came first. We calculated crude and adjusted hazard ratios (HRs) of appendicitis with 95% confidence intervals (CIs) comparing children of mothers who smoked during pregnancy to children of nonsmokers. Further, we conducted a bias analysis and sibling analysis. RESULTS: We included 1,659,526 singletons of whom 19% were born to mothers who smoked during pregnancy. After maximum 28 years of follow-up, hazard rates for children of smokers were slightly higher than for children of nonsmokers [adjusted HR: 1.07 (95% CI = 1.04, 1.10)]. Stratification by sex revealed no association for males [adjusted HR: 1.02 (95% CI = 0.99, 1.06)], but a higher HR for females [adjusted HR: 1.13 (95% CI = 1.09, 1.18)]. This association increased with increasing length of follow-up, indicating that the association may be mediated by later-life exposures. The bias analysis indicated that misclassification of maternal smoking could attenuate a true association, while the sibling analysis showed no association. CONCLUSIONS: Maternal smoking during pregnancy and appendicitis in the offspring may be associated.

Appendicitis in an Appendicostomy.

A 25-year-old man presented with right lower quadrant abdominal wall erythema, a punctum of purulence, and localized pain at the site of a previous appendicostomy. Cross-sectional imaging revealed appendicitis at his previous appendicostomy with a fecalith near the skin. He was managed with appendectomy. The surgical approach mimicked a loop ileostomy reversal by circumferentially dissecting the tissue around the appendicostomy to the level of the fascia and then dividing the appendix at the base of the cecum through a small two-centimeter incision. Appendicitis in a previous appendicostomy is uncommon and has only been described in three previous case reports (two adults and one child) and was surgically approached through a low-midline laparotomy. Our case is unique as it is an uncommon presentation of a common disease managed with a minimally invasive approach not previously described.

[S073]-The impact of interval appendectomy timing on follow-up adverse outcomes.

OBJECTIVE: This study aims to compare the timing of interval appendectomy (IA) and its impact on post-operative outcomes. METHODS: A retrospective analysis was performed for adult patients diagnosed with appendicitis between 2006 and 2017. IA was defined as a follow-up appendectomy > 1 week and < 2 years after the initial presentation. Time intervals were divided into 4 groups based on patient quartiles: 1-6 weeks, 7-9 weeks, 10-15 weeks, and > 15 weeks. The primary outcome measure was length of stay (LOS). Secondary outcomes included 30-day readmission and IA post-operative complications. Tertiary outcomes included 30-day mortality and colonoscopy suggesting neoplasm or Inflammatory Bowel Disease. RESULTS: A total of 5069 patients' records whose interval appendectomy fell > 1 week and < 2 years after initial presentation were analyzed. Among them, 1006 (19.85%) underwent an initial percutaneous abscess drainage at diagnosis. The median timing for IA was 9.2 weeks. Patients with IA at 1-6 weeks were more likely to have longer LOS when compared to 7-9 weeks (ratio 1.33, 95% CI 1.2-1.48) and 10-15 weeks (ratio 1.38, 95% CI 1.25-1.52). IA between 7 and 9 weeks (ratio 0.81, 95% CI 0.73-0.89) and 10-15 weeks (ratio 0.78, 95% CI 0.71-0.86) was associated with significantly shorter LOS compared to those receiving the operation after 15 weeks. Further, patients requiring abscess drainage (ratio 1.2, 95% CI 1.13-1.34) or those with comorbidities (ratio 1.51, 95% CI 1.39-1.63) were more likely to have longer LOS at IA. Socioeconomic and demographic differences including Black, Hispanic, and those with Medicare and Medicaid insurance had a greater LOS after their IA. CONCLUSION: LOS remains lowest among patients undergoing IA between 7-9 weeks and 10-15 weeks after initial appendicitis presentation. Patients with lower socioeconomic status or from racial minorities had a longer LOS after IA.

AbcApp: incidence of intra-abdominal ABsCesses following laparoscopic vs. open APPendectomy in complicated appendicitis.

BACKGROUND: Patients with complicated appendicitis are more at risk for the occurrence of postoperative intra-abdominal abscesses than patients with uncomplicated appendicitis. Studies comparing laparoscopic and open appendectomy showed limitations and contradictory findings on the incidence of intra-abdominal abscesses after appendicitis, as most of these studies analysed both uncomplicated and complicated appendicitis as one group. The aim of the present study is to investigate the incidence of intra-abdominal abscesses after laparoscopic versus open appendectomy for complicated appendicitis. METHODS: A retrospective cohort study was performed over the period January 2009 till May 2020. All patients who had an intra-operative diagnosis of complicated appendicitis (e.g. perforation, necrosis) were included. The outcome measure was the occurrence of intra-abdominal abscesses with a postoperative follow-up of 30 days. Multivariate logistic regression analysis was performed including adjustments for significant confounders. RESULTS: A total of 900 patients had undergone appendectomy for complicated appendicitis. The majority was operated laparoscopically (78%, n = 705). The incidence of postoperative intra-abdominal abscess was 12.3% in both laparoscopic and open appendectomy groups. On univariable analysis, the postoperative rates of intra-abdominal abscesses between laparoscopic and open appendectomy were not significantly different (odds ratio 1.11, 95% CI [0.67-1.84], p = 0.681). CONCLUSION: The present study provides evidence that, in current daily practice, intra-abdominal abscess formation remains a common postoperative complication for complicated appendicitis. Nonetheless, no significant difference was found with regard to intra-abdominal abscess formation when comparing laparoscopy with open surgery.