Impact of peritoneal lavage on intra-abdominal abscess after laparoscopic appendectomy for perforated appendicitis: a propensity score matching analysis

Abstract

Objective

To investigate the impact of peritoneal lavage on the incidence of intra-abdominal abscess (IAA) after laparoscopic appendectomy (LA) in adults with perforated appendicitis.

Methods

Clinical data from adult patients intraoperatively diagnosed with perforated appendicitis and undergoing LA at the Affiliated Hospital of Qingdao University between January 2020 and January 2025 were retrospectively analyzed. Patients were divided into a no-peritoneal lavage group and a peritoneal lavage group based on whether peritoneal lavage was performed. A total of 128 patients were included, comprising 91 in the no-peritoneal lavage group and 37 in the peritoneal lavage group. Patient demographics were collected, and propensity score matching (PSM) was employed to compare clinical data between groups.

Results

After PSM, patient demographics showed no significant differences, indicating good balance (P > 0.05). There were no statistically significant differences between the two groups regarding operative time, postoperative antibiotic duration, postoperative length of stay(LOS), or postoperative IAA incidence (P > 0.05).

Conclusion

Our findings indicate that compared to suction alone, peritoneal lavage did not reduce the incidence of postoperative IAA in adults undergoing LA for acute perforated appendicitis. There is no evidence that patients benefit from lavage. Prospective multicenter randomized controlled trials are warranted.

Introduction

Acute appendicitis is one of the most common abdominal emergencies. Over the past 30 years, its global age-standardized incidence has remained relatively stable at approximately 214 per 100,000 population [1]. Perforation rates range from 16% to 40% [2]. Perforated appendicitis is associated with a reported mortality rate of up to 5% [3] and an increased incidence of postoperative complications [4]. Intra-abdominal abscess (IAA) is a common postoperative complication, occurring in 3% to 26% of patients following surgery for perforated appendicitis [5].

Currently, laparoscopic appendectomy (LA) is the most frequently used and effective surgical approach for patients with perforated appendicitis. Compared to traditional open appendectomy (OA), LA offers advantages including shorter postoperative hospital stay and lower overall complication rates [6]. However, the use of LA does not appear to reduce the incidence of IAA [7].

Peritoneal lavage is a common technique in abdominal surgery. In appendectomy, it aims to physically remove pus, necrotic tissue, fecal matter, and other infectious sources and contaminants to reduce bacterial load and minimize postoperative intra-abdominal infection. However, current guidelines suggest that peritoneal lavage offers no advantage over suction alone [8], and performing irrigation during LA does not appear to reduce IAA incidence. Suction alone is recommended [8]. Some studies even indicate that peritoneal lavage during appendectomy for perforated appendicitis may increase the IAA rate [9]. There is a lack of large-scale, multicenter randomized controlled trials providing sufficient evidence. The decision to perform lavage often relies on the surgeon’s experience and is highly subjective.

Based on the mechanistic role of peritoneal lavage in clearing bacteria and inflammatory mediators, we hypothesized that intraoperative peritoneal lavage would be a protective factor against the incidence of postoperative IAA in patients undergoing LA for perforated appendicitis.

This study employs propensity score matching to analyze the impact of peritoneal lavage on the incidence of postoperative IAA in adults undergoing LA for perforated appendicitis, thereby providing evidence to inform clinical decision-making.

Methods

Study subjects

Clinical data from adult patients who underwent laparoscopic appendectomy (LA) for perforated appendicitis at the Affiliated Hospital of Qingdao University between January 2020 and January 2025 were retrospectively retrieved from the Hospital Information System (HIS).

Inclusion and exclusion criteria

Inclusion Criteria:

1. Age: ≥18 years

2. Intraoperative confirmation of perforated appendicitis

3. Underwent laparoscopic appendectomy

4. Availability of complete clinical data

Exclusion Criteria:

1. Laparoscopic transfer to open appendectomy or open appendectomy

2. Postoperative pathological diagnosis of appendiceal tumor

3. Incomplete clinical data

Observation indicators

Preoperative baseline data collected for enrolled patients included: age, sex, body mass index (BMI), presence of diabetes, presence of immunodeficiency disorders, history of abdominal surgery, time from symptom onset to surgery (hours, h), preoperative maximum body temperature (°C), preoperative white blood cell count (10⁹/L), preoperative neutrophil count (10⁹/L), preoperative lymphocyte count (10⁹/L), preoperative monocyte count (10⁹/L), preoperative C-reactive protein (CRP, mg/L), time from preoperative antibiotic administration to surgery start (h), and CT-measured appendiceal diameter (mm). Laboratory values were the last results obtained prior to surgery.

Intraoperative data included: extent of intra-abdominal infection, occurrence of fecalith spillage, operative time (minutes, min), surgeon’s professional title, whether to place an abdominal drain and whether peritoneal lavage was performed.

Postoperative data included: postoperative length of stay (LOS, days), duration of postoperative antibiotic use (days), occurrence of IAA within 30 days postoperatively, and pathological type.

The primary outcome of this study was the incidence of postoperative IAA. The secondary outcomes included postoperative LOS, duration of postoperative antibiotic use, and operative time.

Extent of intra-abdominal infection was classified based on intraoperative findings: confined (pus localized to the pelvis or right iliac fossa) or diffuse (pus spread diffusely throughout the abdominal cavity).The operating surgeon decided whether to perform peritoneal lavage or place an abdominal drain based on their clinical judgment.Criteria for drain removal were: no further fluid output from the drain, or daily drainage volume less than 20 mL with clear fluid.

Preoperative Empiric Antibiotic Therapy for Broad-spectrum antibiotics, such as cefoperazone-sulbactam or piperacillin-tazobactam and so on, are established as effective by guidelines. Administration should commence immediately upon diagnosis of appendicitis through intravenous infusion, regardless of whether perforation is confirmed.Postoperative antibiotics identical to preoperative agents.Duration of postoperative antibiotic use was determined by the operating surgeon based on criteria including absence of fever, decreasing white blood cell count, decreasing neutrophil count, or improvement in other infection markers.

Diagnostic criteria for IAA formation: Presence of fever and abdominal pain within 30 days postoperatively, confirmed by abdominal CT scan, with or without positive bacterial culture of aspirated pus.

Surgical technique

Following general anesthesia and aseptic draping, a 1–1.2 cm umbilical incision was created for Veress needle insertion to establish pneumoperitoneum (maintained at 12–14 mmHg). A 10/12-mm trocar was then introduced for 30° laparoscope placement. Under direct visualization, two 5-mm operative trocars were positioned at the lower midline abdomen and left contralateral McBurney’s point. Systematic exploration revealed purulent fluid, which was aspirated. The mesoappendix was dissected to its base, followed by endoscopic loop ligation of the appendiceal base – supplemented with absorbable suture reinforcement in perforated cases. The resected specimen was retrieved via the umbilical port using an endoscopic bag.

Peritoneal lavage group: The abdominal cavity was irrigated with warm saline solution until the effluent ran clear, followed by aspiration of the irrigation fluid. After the initial removal of gross pus and exudate, localized lavage was conducted targeting the right lower quadrant (the appendiceal area) and areas of pus accumulation using an irrigator-aspirator system. If pus had disseminated to the pelvic cavity or hepatorenal recess, targeted lavage was applied to these specific areas; systematic lavage of the entire abdominal cavity was not routinely performed. Lavage was continued until the aspirated fluid appeared clear. No-peritoneal lavage group: Pus was aspirated without irrigation.A drainage tube was placed into the lesser pelvis through the midline lower abdominal trocar site.

Statistical analysis

Statistical analyses were performed using SPSS software (version 27.0). Categorical data are presented as [n (%)] and compared between groups using the Chi-square test or Fisher’s exact test, as appropriate. Normally distributed continuous data are expressed as mean ± standard deviation (SD) and compared using the independent samples t-test. Non-normally distributed continuous data are expressed as median (interquartile range [IQR]), i.e., M (P25, P75), and compared using the Wilcoxon rank-sum test.All statistical tests were two-sided, and a P-value < 0.05 was considered statistically significant.

Primary Analysis: In the propensity score-matched cohort, outcomes were directly compared between the peritoneal lavage group and the no-peritoneal lavage group regarding the primary endpoint (incidence of IAA) and secondary endpoints.

Sensitivity Analysis: To evaluate the robustness of the primary findings, a logistic regression model was constructed within the matched cohort, with the occurrence of intra-abdominal abscess as the dependent variable and the application of peritoneal lavage (yes/no) as the independent variable. This analysis aimed to further adjust for any minor residual confounding after matching and to provide a more precise, adjusted estimate of the treatment effect, expressed as an adjusted OR along with its 95% CI.

Results

Study flow

Using the Affiliated Hospital of Qingdao University HIS system, 132 adult patients intraoperatively diagnosed with perforated appendicitis between January 2020 and January 2025 were initially identified. Figure 1 illustrates the study flowchart. Exclusions comprised: 2 patients with postoperative pathology confirming appendiceal tumors,1 patient requiring conversion to open appendectomy and 1 patient undergoing planned open appendectomy. Ultimately, 128 patients were included in the study: No-peritoneal lavage group: 91 patients and peritoneal lavage group: 37 patients.Following 1:1 PSM, 74 patients were included in the analysis (37 per group).

Fig. 1.

Flowchart

Analysis of baseline characteristics

The comparison of baseline clinical characteristics between the two groups before and after PSM is presented in Table 1.Before PSM, no statistically significant differences were observed between the groups regarding age, sex, BMI, smoking history, alcohol consumption history, diabetes history, history of abdominal surgery, preoperative maximum body temperature, preoperative lymphocyte count, preoperative monocyte count, preoperative CRP, CT-measured appendiceal diameter, time from preoperative antibiotic administration to surgery start, time from symptom onset to surgery start, surgeon’s professional title, occurrence of fecalith spillage, placement of an abdominal drain, or pathological type (P > 0.05).However, a statistically significant difference was found in the extent of intra-abdominal infection (P < 0.05). Additionally, no patients with immunodeficiency disorders were present in either group.Following 1:1 PSM, 74 patients were included in the analysis. After matching, the Standardized Mean Differences (SMD) for multiple variables were substantially reduced. All matched variables showed no statistically significant differences between the two groups (P > 0.05), indicating that PSM effectively improved the balance of covariates between the groups. This enhanced balance minimizes the potential influence of confounding factors, making the comparison of outcomes more reliable.

Table 1.

Comparison of baseline characteristics before and after PSM

Variables	Level	Unmatched				Matched
		No-peritoneal lavage group n = 91	Peritoneal lavage group n = 37	SMD△	P-value	No-peritoneal lavage group n = 37	Peritoneal lavage group n = 37	SMD△	P-value
Age(mean (SD))		46.64 (17.87)	48.49 (19.75)	0.094	0.624	47.86 (18.68)	48.49 (19.75)	0.031	0.890
Sex(%)	Female	38 (41.8)	11 (29.7)	−0.263	0.204	12 (32.4)	11 (29.7)	−0.059	0.802
	Male	53 (58.2)	26 (70.3)	0.263		25 (67.6)	26 (70.3)	0.059
BMI (mean (SD))		24.49 (4.00)	24.92 (4.15)	0.103	0.596	25.11 (4.00)	24.92 (4.15)	−0.046	0.840
Smoking(%)	No	80 (87.9)	28 (75.7)	−0.285	0.084	30 (81.1)	28 (75.7)	−0.126	0.572
	Yes	11 (12.1)	9 (24.3)	0.285		7 (18.9)	9 (24.3)	0.126
Drinking(%)	No	82 (90.1)	29 (78.4)	−0.285	0.090	31 (83.8)	29 (78.4)	−0.131	0.553
	Yes	9 (9.9)	8 (21.6)	0.285		6 (16.2)	8 (21.6)	0.131
Prior abdominal surgery(%)	No	76 (83.5)	31 (83.8)	0.007	0.970	30 (81.1)	31 (83.8)	0.073	0.760
	Yes	15 (16.5)	6 (16.2)	−0.007		7 (18.9)	6 (16.2)	−0.073
Diabetes(%)	No	89 (97.8)	33 (89.2)	−0.277	0.058	35 (94.6)	33 (89.2)	−0.174	0.674
	Yes	2 (2.2)	4 (10.8)	0.277		2 (5.4)	4 (10.8)	0.174
Preoperative maximum body temperature(mean (SD))		37.38 (0.98)	37.50 (2.29)	0.052	0.761	37.35 (0.85)	37.50 (2.29)	0.066	0.708
Preoperative white blood cell count(mean (SD))		13.60 (3.69)	14.57 (3.98)	0.242	0.210	14.95 (3.81)	14.57 (3.98)	−0.096	0.675
Preoperative neutrophil count(mean (SD))		11.75 (3.59)	12.55 (3.89)	0.205	0.287	12.82 (3.73)	12.55 (3.89)	−0.070	0.759
Preoperative lymphocyte count(mean (SD))		1.18 (0.65)	1.25 (0.73)	0.099	0.601	1.31 (0.68)	1.25 (0.73)	−0.075	0.738
Preoperative monocyte count(mean (SD))		0.64 (0.35)	0.71 (0.40)	0.196	0.302	0.77 (0.39)	0.71 (0.40)	−0.130	0.573
Preoperative CRP(mean (SD))		75.93 (75.28)	93.07 (82.93)	0.207	0.281	104.18 (89.42)	93.07 (82.93)	−0.134	0.581
Time from symptom onset to surgery start (mean (SD))		49.81 (35.36)	52.76 (27.07)	0.109	0.613	54.27 (38.48)	52.76 (27.07)	−0.056	0.845
Appendiceal diameter(mean (SD))		13.83 (3.54)	14.59 (4.21)	0.181	0.725	14.48 (3.31)	14.59 (4.21)	0.027	0.695
Time from preoperative antibiotic administration to surgery(mean (SD))		2.97 (2.28)	3.03 (2.45)	0.024	0.992	2.73 (1.93)	3.03 (2.45)	0.122	0.831
Surgeon’s professional title(%)	Fellow	3 (3.3)	3 (8.1)	0.176	0.216	3 (8.1)	3 (8.1)	0.000	0.776
	Attending physician	40 (44.0)	10 (27.0)	−0.381		14 (37.8)	10 (27.0)	−0.243
	Senior consultant	23 (25.3)	13 (35.1)	0.207		10 (27.0)	13 (35.1)	0.170
	Professor of surgery	25 (27.5)	11 (29.7)	0.049		10 (27.0)	11 (29.7)	0.059
Extent of intra-abdominal infection(%)	Localized	76 (83.5)	23 (62.2)	−0.440	0.009	25 (67.6)	23 (62.2)	−0.111	0.626
	Widespread	15 (16.5)	14 (37.8)	0.440		12 (32.4)	14 (37.8)	0.111
Presence of fecalith expulsion (%)	No	73 (80.2)	25 (67.6)	−0.270	0.126	26 (70.3)	25 (67.6)	−0.058	0.802
	Yes	18 (19.8)	12 (32.4)	0.270		11 (29.7)	12 (32.4)	0.058
Placement of an abdominal drain (%)	No	44 (48.4)	11 (29.7)	−0.407	0.054	12 (32.4)	11 (29.7)	−0.059	0.802
	Yes	47 (51.6)	26 (70.3)	0.407		25 (67.6)	26 (70.3)	0.059
Pathology (%)	Acute suppurative appendicitis	35 (38.5)	13 (35.1)	0.070	0.725	13 (35.1)	13 (35.1)	0.000	>0.999
	Acute gangrenous appendicitis	56 (61.5)	24 (64.9)	0.070		24 (64.9)	24 (64.9)	0.000

^△Standardized Mean Difference

Intraoperative and postoperative characteristics

The comparison of intraoperative and postoperative characteristics between the two groups is presented in Table 2.No statistically significant differences were observed between the no-peritoneal lavage and peritoneal lavage groups in operative time, duration of postoperative antibiotic use, or postoperative LOS (all P > 0.05).

Table 2.

Comparison of intraoperative and postoperative characteristics between groups after PSM

	Group
Characteristics	No-peritoneal lavage group n = 37	Peritoneal lavage group n = 37	p-value
Operative time [median (IQR)]	65 (40, 90)	75 (55, 95)	0.314
Duration of postoperative antibiotic use [median (IQR)]	4.00 (3.00, 5.00)	4.00 (3.00, 5.00)	0.425
Postoperative LOS [median (IQR)]	6.00 (4.00, 6.00)	5.00 (4.00, 7.00)	0.544

¹Wilcoxon rank-sum tests

Comparison of outcomes between groups

The comparison of postoperative intra-abdominal abscess (IAA) incidence rates between the two groups before and after PSM is presented in Table 3.Both before and after PSM, no statistically significant difference was found in the incidence of postoperative IAA between the two groups (P > 0.05).

Table 3.

Comparison of postoperative IAA incidence between groups before and after PSM

	Unmatched			Matched
Characteristic	No-peritoneal lavage group n = 911	Peritoneal lavage group n = 371	p-value2	No-peritoneal lavage group n = 371	Peritoneal lavage group n = 371	p-value2
IAA			0.056			0.24
No	64 (70%)	32 (86%)		28 (76%)	32 (86%)
Yes	27 (30%)	5 (14%)		9 (24%)	5 (14%)

¹n (%)

²Pearson’s Chi-squared test

To further control for residual confounding factors, enhance the validity of the results, and quantify the effect of performing peritoneal lavage on IAA incidence, logistic regression analysis was performed. The results are presented in Table 4.After PSM, the odds ratio (OR) was 0.49 (95% CI: 0.15–1.62).

Table 4.

Logistic regression analysis of IAA incidence

Characteristic	OR	95% CI	p-value
Unmatched
No-peritoneal lavage group	—	—
Peritoneal lavage group	0.37	0.13, 1.05	0.062
Matched
No-peritoneal lavage group	—	—
Peritoneal lavage group	0.49	0.15, 1.62	0.24

CI Confidence Interval, OR Odds Ratio

Discussion

Acute appendicitis is one of the most common abdominal emergencies worldwide, imposing a substantial burden on global healthcare systems. While prioritizing antibiotic therapy has been proven effective for uncomplicated acute appendicitis, thereby avoiding surgery [10]– [11], surgical intervention remains the preferred approach for perforated appendicitis. With the advancement of laparoscopic techniques, LA has increasingly replaced OA due to advantages including shorter LOS, less postoperative pain, faster recovery, and lower overall complication rates [12]. However, some studies suggest that the incidence of postoperative IAA following LA may not be reduced and could even be higher than after OA [13]. IAA, a common complication after surgery for perforated appendicitis, often necessitates interventions such as intravenous antibiotics, percutaneous abscess drainage, readmission, or even reoperation, depending on the patient’s specific condition. This significantly impacts patients’ quality of life, increases healthcare costs, and prolongs hospitalization. Minimizing the IAA incidence is therefore essential.

Peritoneal lavage is widely used in abdominal surgery. Its application in appendectomy aims to remove pus and reduce postoperative surgical site infection. Fengbo Sun et al. [14] reported that extensive irrigation of the peritoneal cavity during LA could lower the postoperative IAA rate in adults with complicated appendicitis. Conversely, some meta-analyses indicate that peritoneal irrigation does not reduce postoperative IAA rates [15]. Darren Puttock et al. [16] even suggested that irrigation, compared to suction alone, might increase the likelihood of postoperative intra-abdominal fluid collections leading to readmission, a finding consistent with Hani Oweira et al. [17]. Potential reasons for the ineffectiveness of lavage include bacterial adherence to the peritoneal surface, dissemination of bacteria by irrigation, and dilution of immunogenic responders [18]. Consequently, the necessity of peritoneal lavage during LA for perforated appendicitis remains controversial, with no definitive evidence demonstrating patient benefit. The extent of intra-abdominal contamination is a key consideration [19]. Developing precise classification systems for peritoneal contamination severity could benefit future research. Existing classifications, such as the American Association for the Surgery of Trauma (AAST) grades (appendiceal perforation with local contamination, periappendiceal abscess, or generalized peritonitis) [20], or the Gomes et al. [21] grading (3 A: segmental necrosis, 3B: base necrosis, 4 A: abscess, 4B: local peritonitis, 5: diffuse peritonitis), reflect current perspective to studying this issue.

The principal finding of this retrospective cohort study is that, after rigorously balancing baseline confounders—most notably the intraoperative assessment of infection extent—using PSM, we observed no statistically significant reduction in IAA incidence associated with peritoneal lavage in patients undergoing laparoscopic surgery for acute perforated appendicitis.

A critical methodological consideration in our study was the significant baseline disparity in the severity of intra-abdominal infection. Surgeons intraoperatively elected to perform lavage more frequently in cases with diffuse contamination (37.8% in the lavage group vs. 16.5% in the non-lavage group). This practice pattern unequivocally indicates that the decision to irrigate was primarily driven by the perceived severity of contamination, a potent confounding factor. Our use of PSM was therefore essential to simulate a quasi-randomized scenario, creating comparable groups for a more valid comparison of lavage efficacy.

Following PSM, our analysis revealed several key outcomes. First, regarding secondary endpoints such as operative time, postoperative antibiotic duration, and LOS, no significant intergroup differences were detected. The observed trends—a 10-minute longer median operative time yet a 1-day shorter median LOS in the lavage group—were clinically intuitive but statistically inconclusive, likely constrained by the diminished post-matching sample size. This underscores the necessity for larger studies to detect potential subtle differences in these recovery metrics.

Most importantly, the incidence of IAA remained comparable between groups both before and after PSM. To further refine our estimation of the lavage effect while controlling for any residual confounding, we performed a logistic regression analysis on the matched cohort. The resulting odds ratio (OR) of 0.49 suggested a potential halving of the IAA risk with lavage; however, the wide 95% confidence interval (0.15–1.62) and non-significant P-value (P = 0.24) render this finding inconclusive. This statistical instability is a classical hallmark of a study potentially underpowered to detect a clinically relevant effect size or one where unmeasured confounders may still be influential.

We leads to a crucial pathophysiological and technical conjecture: Could the specific technique of lavage explain its apparent lack of efficacy in our cohort? It is well-established that perforated appendicitis causes peritoneal irritation, manifesting as abdominal rigidity and rebound tenderness. This clinical signsuggest that the parietal peritoneum, particularly the anterior abdominal wall (the “ceiling” of the peritoneal cavity), is involved in the inflammatory process. However, based on surgical records, the lavage procedure in our study was typically targeted at areas of gross visible pus, without systematic exploration and irrigation of the anterior parietal peritoneum. It is plausible that residual inflammatory mediators or micro-organisms adherent to this surface could serve as a nidus for ongoing infection, potentially mitigating the benefits of localized lavage. This hypothesis, that the “comprehensiveness” of lavage (e.g., systematic versus targeted) may be a key determinant of outcomes, warrants urgent investigation in future prospective studies.

Furthermore, the value of routine intraoperative pus culture must be emphasized. Identifying predominant pathogens like Escherichia coli and Pseudomonas aeruginosa [22] is paramount for guiding targeted postoperative antibiotic therapy, especially if an IAA develops, and should be a standard component of managing perforated appendicitis.Regrettably, intraoperative pus cultures were not obtained for some patients, which precluded the incorporation of this factor into our analysis. This is an important aspect that should be addressed in future research and clinical practice.

Limitations and Strengths: Our findings must be interpreted within the context of several limitations. Firstly, the inherent constraints of a retrospective design introduce potential for selection and information bias, despite our efforts to mitigate these through PSM. The post-PSM sample size was substantially reduced, increasing the risk of Type II error (failing to identify a true effect) and limiting the stability of our multivariate models. To enhance transparency, we have provided pre-matching baseline data and preliminary results. Throughout the matching process, priority was given to balancing core covariates to strengthen the reliability of the primary conclusions.

Secondly, The inability to conduct subgroup analyses based on contamination severity—stemming from the lack of a definitive, reliable grading system—represents a study limitation. Since the degree of peritoneal soilage is a potential key moderator in the relationship between lavage and outcomes, our results should be interpreted as an average population effect. This caveat, nevertheless, underscores a critical avenue for further scientific exploration.

Thirdly, our follow-up protocol, while standard, revealed that most IAAs presented post-discharge. We lacked systematic data on IAA severity (e.g., size, complexity), standardized complication grades (e.g., Clavien-Dindo), detailed treatment regimens, and their impact on healthcare costs and patient quality of life—all critical dimensions for a comprehensive cost-benefit analysis of any intervention.

Our study should be interpreted as a methodologically rigorous, hypothesis-generating investigation that challenges a long-standing surgical tradition rather than a definitive practice-changing trial. The primary significance of our work lies not in conclusively resolving the debate on peritoneal lavage, but in demonstrating how advanced observational research methods can critically examine entrenched, evidence-free surgical practices.The adoption of PSM, a robust methodology simulating randomization, substantially mitigated selection bias and consequently enhanced the validity of our conclusions. The concomitant presentation of comparative baseline characteristics before and after matching provides a transparent assessment of cohort equilibration. This study furnishes a methodological framework and preliminary clinical justification for a future randomized controlled trial. Such a trial must prioritize establishing validated, granular classifications for appendiceal pathology severity and the extent of peritoneal contamination. Subsequent stratification based on these criteria is imperative to identify subgroups that may derive genuine therapeutic benefit from lavage. Furthermore, comprehensive outcome assessment should extend beyond conventional metrics to include standardized complication grading systems, requirements for re-intervention, healthcare resource utilization, and patient-reported quality of life measures. Collectively, these refinements are essential for advancing toward an evidence-based, individualized surgical paradigm in the management of perforated appendicitis.

Conclusion

Our findings indicate that compared to suction alone, peritoneal lavage did not reduce the incidence of postoperative IAA in adults undergoing laparoscopic appendectomy for acute perforated appendicitis. There is no evidence that patients benefit from lavage. Prospective multicenter randomized controlled trials are warranted.

Abbreviations

PSM

Propensity score matching

IAA

Intra-abdominal abscess

LA

Laparoscopic appendectomy

OA

Open appendectomy

BMI

Body mass index

CRP

C-reactive protein

SMD

Standardized mean differences

LOS

Length of stay

Authors’ contributions

As the first author，Hao Lu was responsible for the study design and methodology, data collection and curation, data analysis, and manuscript writing. As the corresponding author Shikuan Li contributed to the study design, provided resources, supervised the research, and reviewed/edited the manuscript. As the second author，Chengzhi Wang and Hairui Liu participated in data collection and curation, and reviewed/edited the manuscript.As the second author，Feng Cao, Jingchen Ma, and Haoyan Li reviewed and edited the manuscript. All authors had access to the data, significantly contributed to the article, agreed to submit it for publication, and vouched for the integrity, accuracy, and completeness of the data and the fidelity of the trial to the protocol. All authors read and approved the final manuscript.

Funding

None.

Data availability

The datasets used and/or analyzed during the current study are under further analysis and are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This retrospective chart review study involving human participants was in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This study was approved by the Ethics Committee of the Affiliated Hospital of Qingdao University(QYFY WZLL 30256). This study is a retrospective study. The data were approved by the Ethics Committee of Qingdao University Affiliated Hospital for exemption from informed consent, in compliance with Article 39 of the “Ethical Review Measures for Biomedical Research Involving Human Subjects” of the People’s Republic of China: “All data have been anonymized, do not involve privacy or commercial use, do not involve new interventions, and the research risks are no higher than minimal risk,” thus no informed consent from all study participants is required.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.