Evaluation of Risk Factors for Postoperative Infection in 176 Patients Undergoing Laparoscopic Cholecystectomy at a Single Center

Introduction

Laparoscopic cholecystectomy (LC) is a landmark minimally invasive procedure and, since its introduction into clinical practice, has become the standard treatment for symptomatic benign gallbladder diseases, including acute and chronic cholecystitis, symptomatic cholelithiasis, and gallbladder polyps [1,2]. Compared with traditional open cholecystectomy, LC requires only the establishment of a few small incisions on the patient’s abdomen and completes the gallbladder removal operation through laparoscopy and related instruments [3]. This minimally invasive characteristic significantly reduces surgical trauma, alleviates postoperative pain for patients, accelerates their recovery speed, and significantly lowers the incidence of postoperative complications, such as incision infection and intestinal adhesion, which are common complications of traditional open surgery [4]. Due to these advantages, LC has now become the preferred surgical method for treating benign gallbladder diseases such as gallstones and gallbladder polyps worldwide, benefiting a large number of patients every year [5].

However, despite the numerous advantages of LC, the complication of postoperative infection still cannot be ignored [6]. Postoperative infection, as one of the common complications in surgical procedures, not only brings additional discomfort to patients, such as redness and swelling at the incision site, pain, fever, and other uncomfortable symptoms, but also increases the physical and mental burden of patients [7]. More importantly, postoperative infection can affect the postoperative recovery process of patients, prolong their hospital stays, prevent them from returning to normal life and work as planned, and even have adverse effects on the long-term prognosis of patients, such as increasing the risk of long-term complications, such as incision hernia and abdominal adhesions [8].

In recent years, with the widespread application of LC, studies on postoperative infections after LC have gradually increased. Many scholars have explored the risk factors of postoperative infections after LC from various perspectives, covering factors such as patients’ own conditions and surgical operation factors [9]. For instance, Wang et al evaluated risk factors for surgical site infection after LC and reported that older age and diabetes mellitus were significantly associated with infection [10]; whereas other investigators have highlighted surgical factors such as longer operation time and additional procedures as important variables affecting postoperative infections [11].

However, the current understanding of how patient-related characteristics, such as advanced age, hypertension, diabetes, and overall nutritional status reflected by serum albumin (ALB), and perioperative management factors, including operation timing, operation time, and postoperative drainage tube retention time, jointly and independently influence the risk of infection in routine LC practice remains incomplete, and the results of different studies show some inconsistencies. Therefore, it is of particular clinical interest to identify which of these factors are independently associated with postoperative infection and which are potentially modifiable through changes in perioperative management. In-depth analysis of the risk factors for postoperative infections in patients with LC and further clarification of the association between each factor and postoperative infections is of great significance for formulating more precise and effective targeted preventive measures, reducing the incidence of postoperative infections after LC, and improving the surgical safety and prognosis quality of patients. Accordingly, in this single-center retrospective study, we analyzed the clinical data of 176 patients undergoing LC at our hospital to evaluate risk factors for postoperative infection and provide a reference for targeted preventive strategies.

Material and methods

ETHICS APPROVAL:

The study protocol was reviewed and approved by the ethics committee of our hospital (approval No. ZXYJHKYEC-2025-019-01; approved on October 18, 2025). The study was conducted in accordance with the Declaration of Helsinki and relevant national and institutional regulations. Written informed consent was obtained from all patients or their legal guardians before enrollment.

GENERAL DATA:

A total of 176 patients who underwent LC at our hospital from June 2023 to May 2025 were selected as the research participants. This was designed as a single-center retrospective observational study, and all eligible patients who underwent LC during the study period and met the predefined inclusion and exclusion criteria were consecutively included. The inclusion criteria were as follows: (1) diagnosis of benign gallbladder diseases by imaging and pathological examinations; (2) the patient met the surgical indications and underwent LC surgery; and (3) age 18 years or older. The exclusion criteria were as follows: (1) case complicated with tumors; (2) use of immunosuppressant, antibacterial, or hormonal medications within the past 3 months; (3) conversion to open surgery during LC procedure; (4) severe heart and lung diseases; (5) coagulation disorders; and (6) mental disorders. These predefined inclusion and exclusion criteria were used to obtain a relatively homogeneous cohort of adult patients undergoing standard LC and to minimize the influence of severe comorbidities or altered surgical procedures on the risk of postoperative infection. This study was conducted in accordance with relevant national regulations and the principles of the Declaration of Helsinki.

SURGICAL METHOD:

All patients underwent the surgery under the same operation by the doctors of the treatment group. Patient underwent routine general anesthesia and tracheal intubation. A 1-cm incision was made 1 cm above the patient’s navel, and a 10-mm Torcar was inserted to establish a carbon dioxide pneumoperitoneum. An incision was made at the lower part of the xiphoid process to insert a 12-mm Torcar for placing an electrocoagulation hook or ultrasonic knife. Subsequently, an incision was made below the right midclavicular line at the rib margin to insert a 5-mm Torcar for placing a forceps. The physician used laparoscopy to examine the condition of the abdominal cavity. If necessary, the physician performed fine needle puncture to reduce pressure in the gallbladder, dislocated the gallbladder triangle area, ligated and severed the gallbladder artery, and dislocated, ligated, and cut the gallbladder duct. Using a combination of forward and reverse methods, the physician freed the gallbladder away from the peritoneum and completely removed the gallbladder through a subxiphoid incision. The wound was coagulated with electricity to stop the bleeding. After observing that there was no obvious bleeding or bile leakage from the wound, an abdominal drainage tube was placed in the gallbladder bed. It was led out through the right Torcar hole and fixed. The incision was then sutured and closed one by one.

POSTOPERATIVE INFECTION ASSESSMENT:

According to the “Chinese Guidelines for the Prevention of Surgical Site Infections” and the “Hospital Infection Diagnosis Standards (Trial)”, the specialist nurses evaluated the occurrence of postoperative infections in patients as follows: (1) local incision shows redness, fever, or pain, or has purulent discharge, and the culture result of the discharge is positive; (2) deep incision has discharge or puncture extracts pus; and (3) the patient has symptoms such as fever, abdominal pain, or jaundice, and the specimens obtained from the surgical incision or drainage tube have detected pathogens, or the blood culture result is positive, and the pathogen is the same as the local infection or consistent with the clinical situation. If any of the above conditions were met, it was determined as postoperative infection, and the patient was included in the occurrence (infection) group; otherwise, the patient was included in the non-occurrence (noninfection) group. Based on these clinical manifestations and microbiological findings, postoperative infections in this study were classified as local incisional infections, deep incisional infections, or systemic infections (biliary or abdominal infections or bloodstream infections that fulfilled the above diagnostic criteria). In the present study, this binary classification (occurrence vs non-occurrence of postoperative infection), as defined by the Chinese Guidelines for the Prevention of Surgical Site Infection, was pre-specified as the primary outcome variable. If a common inflammatory infection occurred postoperatively, cefazolin was used for treatment, 2 g each time, twice a day. If a severe infection occurred, cefoperazone sulbactam was used, 3 g each time, 3 times a day.

CLINICAL DATA COLLECTION:

The clinical information of the patients was recorded, including sex, age, body mass index, history of diabetes, history of hypertension, history of abdominal surgery, combination with gallbladder stones, combination with acute inflammation of the gallbladder, operation timing, operation time, postoperative drainage tube retention time, and American Society of Anesthesiologists (ASA) grade. All of these variables were obtained from the hospital electronic medical record system and the operating room information system using a predesigned standardized data collection form. Operation timing was defined as the time interval from the onset of acute symptoms to the performance of LC (≤72 hours vs >72 hours). Operation time was defined as the period from skin incision to completion of skin closure (≤2 hours vs >2 hours). Postoperative drainage tube retention time was defined as the number of full days from the end of the operation to the removal of the abdominal drainage tube (≤5 days vs >5 days). After extraction, the dataset was checked for completeness and logical consistency before statistical analysis. These variables were collected to explore their association with postoperative infection in univariate comparisons and multivariate logistic regression analysis.

LABORATORY DETECTION:

Before the operation, 5 mL of peripheral venous blood was collected from the patient in the morning on an empty stomach; 2 mL of this blood was used to measure the levels of white blood cell (WBC) count and platelet (PLT) count using an automatic blood analyzer. The remaining 3 mL of blood was centrifuged at 3500 rpm for 15 minutes to obtain the serum. Serum ALB level was detected using the bromophenol green method, and procalcitonin (PCT) was detected using the chemiluminescence method. All assays were performed in the hospital central laboratory according to the manufacturers’ instructions and the laboratory’s internal quality control procedures. WBC and PLT were reported in ×10⁹/L, ALB in g/L, and PCT in ng/mL. For each patient, the preoperative laboratory values used in the analysis were obtained within 24 hours before surgery.

STATISTICAL ANALYSIS:

Data analysis was conducted using SPSS 22.0 statistical software (IBM Corp, Armonk, NY, USA). Categorical variables were expressed as the number of cases and percentages, and comparisons between the infected and noninfected groups were performed using the χ2 test. Continuous variables were presented as the mean±standard deviation. For continuous variables, including the preoperative laboratory indices WBC, PLT, PCT and ALB, between-group differences were assessed using independent-samples t tests. The individual values of these indices for each group were then plotted as scatter plots with overlaid group means, and the corresponding P values (not significant [ns] or P<0.001) are displayed above each panel in Figure 1.

Initially, univariate analyses were carried out to identify factors associated with postoperative infection; variables with P<0.05 in these comparisons (age, history of hypertension, history of diabetes, gallbladder stones, acute inflammation of the gallbladder, operation timing, operation time, and postoperative drainage tube retention time) were considered candidate predictors, whereas variables without statistical significance (sex, body mass index, history of abdominal surgery, and ASA grade) were not entered into the multivariate model. These candidate predictors were then entered into a multivariate logistic regression model to determine independent risk factors for postoperative infection, with postoperative infection set as the dependent variable (no infection=0, infection=1). The independent variables were coded as follows: age (≤60 years=0, >60 years=1), history of hypertension (no=0, yes=1), history of diabetes (no=0, yes=1), presence of gallbladder stones (no=0, yes=1), acute inflammation of the gallbladder (no=0, yes=1), operation timing (≤72 hours=0, >72 hours=1), operation time (≤2 hours=0, >2 hours=1), postoperative drainage tube retention time (≤5 days=0, >5 days=1), and preoperative ALB level (entered as a continuous variable). The enter method was used to fit the model, and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) and P values were calculated for each covariate. A 2-sided P<0.05 was considered statistically significant.

Results

OCCURRENCE OF POSTOPERATIVE INFECTION:

Among the 176 patients with LC, there were no cases of exclusion or dropout. During the hospitalization period, 35 patients (19.89%) developed infections, while 141 patients (80.11%) did not experience any infections. Illustrative imaging examples of these postoperative infectious complications, including intra-abdominal abscess, bile leak–related fluid collection, and port-site wound infection, are shown in Figure 2.

COMPARISON OF GENERAL CLINICAL DATA BETWEEN THE INFECTED AND NONINFECTED GROUPS:

As shown in Table 1, there were significant differences between the infected group and noninfected group in terms of age, history of diabetes, history of hypertension, combination with gallbladder stones, combination with acute inflammation of the gallbladder, operation timing, operation time, and postoperative drainage tube retention time (P<0.05).

COMPARISON OF PREOPERATIVE LABORATORY INDICES BETWEEN THE INFECTED AND NONINFECTED GROUPS:

As shown in Figure 1, the preoperative ALB level was significantly lower in the infected group than in the noninfected group (P<0.001), whereas there were no statistically significant differences in the preoperative WBC, PLT, and PCT levels between the 2 groups (all P>0.05). In Figure 2, each dot represents an individual patient value, the horizontal line indicates the group mean, and the corresponding P value (ns or P<0.001) for the independent-samples t test is displayed above each panel.

MULTIVARIATE LOGISTIC REGRESSION ANALYSIS OF RISK FACTORS FOR POSTOPERATIVE INFECTION:

As shown in Table 2, postoperative infection was taken as the dependent variable (no infection=0, infection=1), and age (≥60 years=1, <60 years=0), history of hypertension (yes=1, no=0), history of diabetes (yes=1, no=0), presence of gallbladder stones (yes=1, no=0), acute inflammation of the gallbladder (yes=1, no=0), operation timing (>72 hours=1, ≤72 hours=0), operation time (>2 hours=1, ≤2 hours=0), postoperative drainage tube retention time (>5 days=1, ≤5 days=0), and preoperative ALB level (continuous variable) were included as independent variables in the multivariate logistic regression model. The analysis showed that age of 60 years or older, history of hypertension, history of diabetes, presence of gallbladder stones, acute inflammation of the gallbladder, operation timing greater than 72 hours, operation time greater than 2 hours, postoperative drainage tube retention time greater than 5 days, and decreased preoperative ALB were independent risk factors for postoperative infection after LC (all P<0.05), and the corresponding adjusted odds ratios and 95% CIs are presented in Table 2.

Discussion

In this single-center retrospective study of 176 patients undergoing LC, postoperative infection occurred in 19.9% (35/176) of patients. Multivariate logistic regression analysis showed that age 60 years or older, history of hypertension, history of diabetes, presence of gallbladder stones, acute inflammation of the gallbladder, operation timing over 72 hours, operation time over 2 hours, postoperative drainage tube retention time over 5 days, and decreased preoperative serum ALB were independent risk factors for postoperative infection. These findings indicate that patient-related factors (advanced age and cardiometabolic comorbidities) and modifiable perioperative management factors (surgical timing, operation duration, drainage duration, and preoperative nutritional status) jointly and significantly contribute to the risk of postoperative infection after LC, underscoring the need for early identification of high-risk patients and targeted preventive strategies.

Several previous studies have also investigated risk factors for postoperative or surgical site infections after LC. Wang et al retrospectively analyzed patients undergoing LC and reported that prophylactic antibiotics reduced the incidence of surgical site infections, while older age and diabetes mellitus were important risk factors for infection [10]. Our findings are partly consistent with those of Wang et al, in that age and diabetes emerged as independent predictors in our multivariate model. However, in our cohort we additionally identified the presence of gallbladder stones, acute inflammation of the gallbladder, delayed operation timing (>72 hours), prolonged operation time (>2 hours), prolonged postoperative drainage tube retention (>5 days), and decreased preoperative ALB as significant risk factors, which may reflect differences in case mix, perioperative prophylaxis protocols, and analytical approaches between studies.

Through multivariate logistic regression analysis, we found that age of 60 years or older, history of hypertension, history of diabetes, combined with gallbladder stones, combined with acute inflammation of the gallbladder, operation timing greater than 72 hours, operation time greater than 2 hours, postoperative drainage tube retention time greater than 5 days, and decreased ALB were independent risk factors for postoperative infection of patients after LC. The 8 reasons are as follows. (1) Due to the gradual decline of organ functions and weakened immunity in older adult patients, this situation becomes increasingly prominent with age. The patients’ ability to resist infections gradually decreases, thereby increasing the risk of postoperative infection. Consistently, a study proposed by Fletcher et al showed that there is a significant correlation between age and complications of LC [12]. (2) Many patients with benign gallbladder diseases often have various underlying diseases, such as hypertension and diabetes, which can lead to a decline in physical health and further reduce immune levels. After surgery, their ability to resist the invasion of pathogenic bacteria is insufficient, increasing the risk of incision infection. These underlying diseases can also cause a decrease in the metabolic rate of tissues and cells throughout the body. Patients with hypertension will have varying degrees of deterioration in vascular endothelial relaxation function, while patients with diabetes will experience an abnormal increase in plasma osmotic pressure. High blood sugar is also conducive to the growth and reproduction of various pathogenic bacteria, such as Escherichia coli [13]. Similarly, Jaafar et al indicated that certain comorbidities, including diabetes and obesity, have an impact on the risk for postoperative infection after LC [14]. (3) Patients with gallbladder stones have an increase in pressure within the bile ducts, due to the long-term compression by the stones. This can lead to strangulation, causing many microorganisms to enter the bloodstream, subsequently resulting in the colonization of bacteria at the incision site, thereby increasing the risk of postoperative infection. Additionally, the long-term compression of the stones can cause the bile ducts to become thinner. During the surgical procedure, the liver ducts are prone to be damaged due to this, making them highly susceptible to contamination by bacteria from the stones, which can subsequently lead to intracavitary infections. Moreover, when the stones are removed from the gallbladder, if they are too large and hard, they can compress the incision tissue, causing tissue deformation and necrosis. (4) Patients with acute inflammation of the gallbladder exhibit significant inflammatory responses, which leads to the impairment of the intestinal mucosal barrier function and makes it difficult to effectively resist the invasion of pathogenic bacteria. Moreover, acute inflammation of the gallbladder can cause gallbladder tissue edema, thereby increasing the difficulty of the surgery. (5) Studies have shown that currently in clinical practice, the surgical time limit for emergency LC is set within 72 hours after the onset of the disease [15]. The main reason is that during this period, the tissue in the patient’s affected area has less adhesion, which is conducive to separating the adhesion and reducing the difficulty of the surgery. However, if the surgery is performed after 72 hours, the continuous inflammatory stimulation will cause various inflammatory cells, fibrin exudation, and a large amount of fibrin to adhere to the surface of the gallbladder serosa, leading to congestion and edema and increasing the risk of bile duct injury, and thereby easily causing the problem of infectious bile contamination of the wound. Therefore, patients with benign gallbladder diseases who have surgical indications should undergo surgical treatment as soon as possible. If the surgical timing exceeds 72 hours, the patient’s inflammatory response should be actively controlled, and the risk of infection should be reduced. Consistently, it has been reported that delaying gallbladder removal surgery can increase the risk of recurrent cholangitis, and the incidence of postoperative complications will also be higher [16]. (6) Studies have shown that the longer the surgery time, the longer the tissue in the surgical area is exposed. At the same time, prolonged exposure of the patient’s incision can cause the fat layer to oxidize and decompose due to mechanical force, triggering an aseptic inflammatory reaction and causing infection of the incision. Consistently, Timerbulatov et al indicated that surgery time over 150 minutes was one of the most significant factors that affected the development of infectious complications after LC [17]. (7) The longer the postoperative drainage tube is left in place, the higher the risk of pathogenic bacteria carried by the drainage tube entering the patient’s body will be, and the risk of incision infection for the patient will also increase accordingly. Likewise, Liu et al indicated that drainage time is an independent risk factors for postoperative wound infection in lumbar spondylolisthesis [18]. Finally, (8) ALB is a commonly used indicator reflecting the overall nutritional status of the body [19]. A decrease in ALB level suggests that the patient’s immune system is weakened, and the ability to resist and eliminate pathogenic bacteria is also reduced. Consistently, Ishii et al indicated that postoperative decrease in serum ALB level is a predictor of early acute periprosthetic infection after total knee arthroplasty [20].

However, several limitations of the present study and its methods should be acknowledged. First, this was a retrospective single-center analysis with a relatively small sample size (176 patients, including 35 with postoperative infection); therefore, selection bias and residual confounding cannot be completely excluded, and the findings may not be generalizable to other institutions or settings. Second, all data were obtained from routinely collected electronic medical records and guideline-based clinical documentation; although we used the Chinese Guidelines for the Prevention of Surgical Site Infection to define postoperative infection, some misclassification of infection status or severity and incomplete capture of potential risk factors (such as detailed intraoperative contamination grading and surgeon experience) may have occurred. Third, perioperative management, including surgical technique, drainage practices, and antibiotic prophylaxis, was not randomized but followed local protocols; therefore, our results demonstrate associations rather than causal relationships. Fourth, for the purposes of clinical interpretation and logistic regression modelling, several continuous variables (such as age, operation time, drainage tube retention time, and preoperative ALB) were dichotomized, which may have led to loss of information on dose-response relationships and a reduction in statistical power. Finally, we did not perform external validation or develop a formal predictive risk score, and we did not assess long-term outcomes beyond the immediate postoperative period; therefore, further multicenter prospective studies with larger samples and more comprehensive variables are needed to confirm and refine our findings.

Conclusions

In this single-center retrospective study of 176 patients undergoing LC, age 60 years or older, history of hypertension, history of diabetes, presence of gallbladder stones, acute inflammation of the gallbladder, operation timing more than 72 hours, operation time more than 2 hours, postoperative drainage tube retention time more than 5 days, and decreased preoperative serum ALB level were independently associated with postoperative infection. These findings indicate that patient-related characteristics and modifiable perioperative factors, including timely scheduling of surgery, avoiding unnecessarily prolonged operation and drainage, and optimizing preoperative nutritional status, should be addressed to reduce postoperative infections and improve outcomes.