Comparative analysis of surgical site infection rates between transumbilical and periumbilical incisions in laparoscopic cholecystectomy: a randomized controlled trial

The RCT was conducted from December 2021 to December 2023 at Panyananthaphikkhu Chonprathan Medical Center (PCMC), Nonthaburi, Thailand, a single tertiary medical center. The trial was registered with the Thai Clinical Trials Registry (TCTR) (ID TCTR20231012002) and approved by the Institutional Review Board of PCMC with the ID EC 014/64. The study adheres to the CONSORT guideline [15]. Inclusion criteria were patients over 18 undergoing laparoscopic cholecystectomy, while exclusion criteria included patients with acute cholecystitis, pregnancy, immunocompromised status, ascites, and those receiving peritoneal dialysis.

Patients were randomly assigned to two groups, PUI and TUI at a 1:1 allocation ratio. All patients provided written consent to enroll in the study. Sealed opaque envelopes with notes marked with either transumbilical or periumbilical, were placed in the operating room. A perioperative antibiotic regimen consisting of a third-generation cephalosporin was administered intravenously within 30 min prior to incision. The antibiotic therapy was continued for less than 24 h postoperatively. In patients with cephalosporin allergies, a quinolone antibiotic was administered as an alternative. Following general anesthesia, surgeons selected an envelope and followed the incision instructions.

The surgical procedure involved creating a camera port incision, either a vertical transumbilical or a periumbilical incision. The periumbilical incision could be either horizontal supraumbilical or infraumbilical. The open Hasson technique was employed for abdominal entry. A 12-mm trocar port was inserted after the abdominal wall was opened, pneumoperitoneum was established, and a 10-mm camera was introduced for intraperitoneal inspection. Subsequently, two or three working 5 mm ports were added. The gallbladder was retracted, Calot’s triangle dissected, and the cystic duct and artery clipped and divided. The gallbladder was dissected from the liver bed, with any bile spillage or contamination promptly controlled. The specimen was placed in a bag to prevent contamination during removal through the umbilical incision. Closure of the fascia was performed using J-shaped needle interrupted absorbable polyglactin Novosyn® 2–0 sutures, while the skin was closed with subcuticular glyconate monofilament Monosyn® 4–0 sutures. Sterile strips were then applied for wound closure.

Patient demographics, perioperative details, and postoperative data of the patients were extracted from recorded documents. Follow-up assessments were conducted up to 30 days post-surgery, with SSI as the primary focus. SSI was defined according to the Centers for Disease Control (CDC) guidelines, defining infections occurring within 30 days post-procedure, exhibiting symptoms like purulent drainage, pain, tenderness, swelling, redness, wound dehiscence, or positive cultures [16]. SSI assessments were carried out before discharge, as well as at 7- and 30-day post-surgery. Secondary outcomes included length of hospital stays, operative time, blood loss, conversion rate, post-laparoscopic cholecystectomy complications, cosmetic satisfaction, pain score, wound hypersensitivity, and numbness. Pain levels were assessed 24- and 48-h post-operation using a visual analogue scale (VAS) ranging from 0 to 10. Cosmetic satisfaction was appraised using a VAS at both 7 and 30 days after the surgery, also on a scale of 0 to 10.

The sample size was determined based on a study by Siribumrungwong et al., indicating a 4% SSI rate for PUI compared to 16% for TUI three months postoperatively [14]. The sample size calculation assumed a two-sided alpha level of 5% and a power of 80%, resulting in a target of 71 participants per group. Accounting for a 10% potential loss to follow-up, resulted in a total of 78 participants.

The statistical analysis was conducted using IBM SPSS Statistics for Windows, Version 22.0 (IBM Corp., Armonk, NY, USA). Continuous variables were presented as mean ± standard deviation. Categorical variables were compared using the chi-square test or Fisher’s exact test, while differences in continuous variables between groups were assessed using the Student’s t-test. P-value < 0.05 was considered statistically significant.

A total of 156 patients were enrolled, with 78 patients assigned to both the PUI and TUI groups as shown in Fig. 1. Demographic data, as depicted in Table 1, were comparable between the two groups, with none presenting liver disease. More than half of the patients in both groups presented as symptomatic gallstones along with a similar proportion presenting comorbidities. Morbid obesity was observed in 6 patients (7.7%) in each group. Pathological reports indicated chronic cholecystitis in all cases, except for one patient in the TUI group, who had a gallbladder polyp.

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The outcomes in Table 2 reveal comparable SSI rates between the TUI and PUI groups, 11 (14.1%) and 8 (10.3%) respectively (p = 0.46). If the specimen was larger than the incision, an extension of the sheath and skin was performed; however, the total length of the incision did not exceed 2 cm (cm). Neither group experienced conversions to open surgery, bile leaks, intraabdominal infections, reoperations, nor mortality. However, one patient in the TUI group required a blood transfusion due to a blood loss of 800 ml. In the PUI group, two patients experienced atrial fibrillation with rapid ventricular response, which resolved quickly, leading to discharge on postoperative days 3 and 6 without SSI. Also, one patient in the TUI group experienced atrial fibrillation with rapid ventricular response, lung atelectasis, and SSI, resulting in discharge on postoperative day 11. Cosmetic satisfaction, wound numbness, and wound hypersensitivity outcomes were similar in both groups, with no occurrences of umbilical hernia 30 days post-surgery.

Factors contributing to SSI were analyzed, with none found to be significant, as shown in Table 3. None of the morbidly obese and chronic kidney disease patients have SSI. Patients with SSI exhibited lower cosmetic satisfaction scores on day 7 post-surgery (8.47 ± 1.3) compared to the non-SSI group (9.5 ± 0.8) (p < 0.001). However, cosmetic VAS scores were comparable between both groups on day 30 (9.16 ± 1 vs 9.52 ± 0.7, p = 0.19). The SSI group demonstrated a higher prevalence of umbilical wound hypersensitivity at day 30 post-surgery [11 (57.9%) vs 35(25.7%), p = 0.04]. Postoperative pain scores and wound numbness did not differ between the groups, as demonstrated in Table 4.

Both PUI and TUI are popular surgical approaches worldwide [6, 7]. The advantages of the TUI were less time-consuming to reach intraperitoneal and more useful in morbidly obese patients due to their thick subcutaneous fat [7]. However, this study did not record the time for opening or wound closure, making it difficult to confirm the time-saving benefit of the TUI approach. Previous RCTs on SSI in laparoscopic cholecystectomy have yielded conflicting results. One study reported no significant difference, with a 16% SSI rate for TUI compared to 4% for PUI [14]. Another study found a significant difference, with 0% SSIs in TUI compared to 3% in PUI [13]. However, a meta-analysis concluded that there were no significant differences in SSI rates between the two methods [17]. Our RCT findings align with this meta-analysis, showing no significant difference in SSI rates between TUI and PUI (14.1% for TUI vs. 10.3% for PUI, p = 0.46). The concern of the surgical site of TUI did not increase the infection rate [10, 11]. Therefore, if the surgeon prefers the TUI, it suggests that surgeons can choose either incision based on their preference without increasing the risk of infection [8, 9].

In terms of intraoperative outcomes, our study found no significant differences in operative time, blood loss, or blood transfusion requirements between the two incision types. Additionally, there were no conversions to open surgery, bile leaks, intra-abdominal infections, reoperations, or mortalities in either group, indicating that both methods are safe for patients.

Consistent with the previous study, we found similar results for cosmetic satisfaction, wound numbness, and wound hypersensitivity, with no occurrences of umbilical hernia 30 days post-surgery [13]. Therefore, we conclude that there are no significant differences between PUI and TUI in terms of operative procedures, wound outcomes, and overall short-term safety.

Regarding cosmetic satisfaction, the appearance of the umbilicus is important to some patients, with 28–39% considering it a significant aspect of their overall appearance [18, 19]. It was previously mentioned that the TUI incision, by hiding the scar, would result in higher patient satisfaction [13]. However, our study found no significant difference in cosmetic satisfaction between the two groups at one week and one month post-surgery, which supports earlier research [8, 18]. Similarly, wound numbness and hypersensitivity were comparable between the two groups. Thus, cosmetic concerns should not determine the choice of incision type.

Umbilical hernias at the trocar site are classified into three distinct types. The first type is early-onset, which typically manifests immediately postoperatively, often due to surgical technique. The second type, late-onset hernia, occurs several months after the surgical procedure. The third type is characterized by the protrusion of intra-abdominal contents, such as the intestine and/or omentum [20]. In studies with shorter follow-up durations, the incidence of umbilical hernias was reported to be low, ranging from 0.18 to 2.8% [21]. However, with extended follow-up periods, the incidence increases, with the time to occurrence ranging from 9 to 70 months, with a median of 42.4 months [22]. To more accurately assess the true risk of incisional hernias, a follow-up period of at least 3 years is recommended [22, 23]. Longer follow-up periods have shown an increased incidence of 11.7–12.1% [21, 22]. Several factors have been identified as contributing to the increased incidence of umbilical hernias, including high body mass index (BMI), a prior history of umbilical hernia, incision length greater than 5 cm, and prolonged operative time [22]. In patients undergoing laparoscopic sleeve gastrectomy, the incidence of umbilical hernias was as high as 21.5%, with a mean follow-up period of 37 months [23]. This particular study, with only a 30-day follow-up and no occurrences, showed results consistent with those of a previous study [7]. Thus, short follow-up periods may only detect early-onset hernias. Further studies with extended follow-up are warranted to evaluate the long-term outcomes and potential risk factors associated with umbilical hernias.

Factors influencing SSI include patient factors such as age, nutritional status, and obesity; procedural factors, with laparoscopic approaches generally tending to lower SSI incidence; and microbial factors [16, 24, 25]. Studies have shown that umbilical flora and bile are not the primary sources of SSIs in laparoscopic surgeries. Instead, hospital-acquired pathogens or intra-abdominal contamination are more likely responsible for infections [10, 26]. Interestingly, in our study, patient status was not found to significantly affect SSI rates, and none of the patients with renal disease and morbid obesity encountered SSI. However, the low number of patients with SSIs suggests that the sample size may have been insufficient to evaluate significant differences, which could explain the discrepancy with previous studies. Patients who developed SSIs also reported higher wound hypersensitivity and lower cosmetic satisfaction, which is consistent with expectations.

Our study does have limitations, including being a single-center study with a short follow-up period. Future research should focus on larger, multicenter trials and long-term outcomes, including incision opening and closing times, umbilical hernia occurrence, wound numbness, hypersensitivity, and cosmetic results to provide a more precise agreement.

This study shows that there is no statistically significant difference in SSI rates between TUI and PUI in laparoscopic cholecystectomy, indicating that both incision types are practicable options with comparable outcomes regarding operative safety and overall patient satisfaction. This finding supports the use of either practice based on surgeon preference and patient-specific considerations.