Ultrasound-guided percutaneous drainage of collections in difficult locations after pancreaticoduodenectomy: experiences from a single Chinese institution

Introduction

Background

Pancreaticoduodenectomy, also known as the Whipple procedure, is the primary surgical approach for treating malignant tumours of the pancreas and adjacent organs (1,2). Although advancements in surgical techniques and postoperative management have enhanced patient safety (3,4), the incidence of postoperative complications remains relatively high, ranging from 20% to 40% (5-7). Among these, postoperative fluid collections in the surgical area are relatively common, with an incidence rate of approximately 10–30% (5,8,9). These collections may induce clinical symptoms such as abdominal pain and distension by compressing surrounding tissues and organs. They may also lead to life-threatening complications, such as pseudoaneurysms. Therefore, early identification and management of these collections in the surgical area are crucial for improving patient outcomes (6,7).

Rationale and knowledge gap

Currently, treatment modalities for postoperative collections include conservative therapy, percutaneous drainage, and surgery (10,11). When conservative therapy is ineffective, percutaneous drainage is preferred over reoperation due to the minimally invasive nature. Among various drainage techniques, ultrasound-guided percutaneous drainage has become the preferred treatment modality due to its lack of radiation exposure and high success rate (12-15). Despite significant achievements, managing fluid collections in anatomically complex regions remains challenging. This is often attributed to the deep location of the fluid and its obstruction by the intestines or other organs, which affects the visualization of ultrasound and prevents straightforward access routes. These limitations may result in procedural failure, treatment delays, and increased risks of infection, bleeding, or other adverse events. Therefore, effective management of these challenging collections is a critical clinical issue (7).

Objective

This study aims to evaluate the efficacy and safety of an improved ultrasound-guided percutaneous drainage in the management of challenging fluid collections following pancreaticoduodenectomy. We present this article in accordance with the STROBE reporting checklist (available at https://gs.amegroups.com/article/view/10.21037/gs-2025-278/rc).

Methods

Ethical approval

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the ethics committee of The First Affiliated Hospital of Zhejiang University School of Medicine (Reg. No. 2025B-0356) and the requirement for informed consent was waived owing to the retrospective nature of the study.

Study design and patient selection

This retrospective analysis was performed on the medical records of patients who underwent pancreaticoduodenectomy at the Qingchun Campus of The First Affiliated Hospital of Zhejiang University School of Medicine between January 2023 and September 2024. Inclusion criteria: (I) patients with fluid collection in the surgical area after pancreaticoduodenectomy; (II) patients who received ultrasound-guided percutaneous drainage. Exclusion criteria: (I) patients with fluid collections in anatomically accessible sites with no major organs obstructing the pathway; (II) cases with incomplete imaging or clinical records.

Data collection

Patient information was extracted from the hospital’s electronic medical record database. Data collected included basic demographic details such as age and gender, as well as the duration of the procedure, the type of procedure, and postoperative pathological findings. In addition, the time of onset and the location of the collections were documented, as well as the outcome of the procedure and postoperative complications.

Pre-operative patient preparation

Patients should fast for at least 8 hours and refrain from drinking for 4 hours before the procedure. Informed consent must be obtained from the patient or their legal representative before the procedure, with a detailed explanation of the surgical risks, expected outcomes, and potential consequences. Pre-operative blood tests, including a complete blood count and coagulation tests, should be performed. In addition, it is important to ask if the patient is taking any medication that could affect coagulation. If the platelet count is below 50,000/µL, the prothrombin time is more than 1.5 times normal, or the patient is taking anticoagulant medication, preoperative intervention or postponement of surgery should be considered. Abdominal computed tomography (CT) or magnetic resonance imaging (MRI) should be performed preoperatively to assess the location, size, and relationship of the fluid collection to surrounding tissues. Ultrasound should be used to confirm the location and characteristics of the fluid collection. If necessary, contrast-enhanced ultrasound (CEUS) may be used to improve visualisation of the fluid collection.

Puncture techniques

All procedures are performed under local anaesthesia with continuous monitoring of heart rate, blood pressure, and oxygen saturation throughout the procedure. The main strategy for collections in difficult locations is to use various techniques to create viable puncture paths. Methods include the following.

Hydrodissection

First, connect a Chiba needle (with the stylet removed) to an extension tube and attach the extension tube to a 50-mL syringe. Use normal saline to flush out the air from both the extension tube and the needle. Under local anaesthesia with lidocaine, insert the needle tip into a small interstitial space, such as the hepatogastric or gastrointestinal space. An assistant injects saline to create a separation between the tissues. The needle is then advanced until it enters the target fluid collection (as shown in Figure 1). The fluid is aspirated to assess its characteristics. A guide wire is then inserted through the needle, followed by placement of a drainage catheter along the guide wire. Once the catheter has been successfully placed, a collection sample is aspirated with a 5-mL syringe for bacteriological analysis. Finally, connect the drainage bag and secure the catheter to the skin.

Figure 1 Schematic of hydrodissection technique. (A) Insert the needle tip into a small interstitial space; (B) inject normal saline to create a separation between the tissues; (C) the needle enters the target fluid collection.

Modified trocar technique

Under local anesthesia, the multipurpose pigtail catheter is directly inserted into the anterior margin of a tissue space, such as the hepatogastric space. The trocar stylet is then retracted by approximately 1 cm to ensure that the tip of the catheter is blunt. At this stage, the catheter is advanced along the tissue space, using a technique similar to blunt dissection in surgery, until it approaches the target fluid collection. After confirming the position of the catheter tip and ensuring that there were no vessels in its path, the stylet is reinserted to guide the needle into the target area (as shown in Figure 2). The catheter is then placed, and a collection sample is taken for bacteriological testing. Finally, the catheter is secured to the skin, and a drainage bag is attached.

Figure 2 Schematic of modified trocar technique. (A) Directly insert the catheter into the anterior margin of a tissue space; (B) retract the trocar stylet; (C) reinsert the needle and guide it into the target area.

Transhepatic method

This procedure is similar to the routine method. Under local anesthesia, the catheter passes through the liver into the target area. The following procedure is the same as the previous methods, including laboratory tests and catheter fixation.

Post-operative management

Postoperative vital signs such as pulse, respiration, and blood pressure need to be closely monitored for early detection of potential complications. Technical success was defined as the placement of the drainage catheter within the target area, confirmed by ultrasound or CT. Clinical success was defined as the absence of collection-related clinical symptoms after catheter removal. The key criterion is the absence of residual fluid at the drainage site on imaging. Procedure duration was defined as the time from the initiation of local anesthesia to the completion of drainage catheter fixation. Complications assessed in this study included catheter displacement, pain, bleeding, and sepsis. According to the Society of Interventional Radiology (SIR) standards, complications requiring further treatment, elevated level of care, prolonged hospitalization, permanent adverse sequelae, and death are considered severe complications.

Statistical analysis

First, the Shapiro-Wilk test and histograms were used to assess normality for discrete and continuous variables. Normally distributed variables are presented as mean ± standard deviation (SD), while non-normally distributed variables are represented by the median [interquartile range (IQR)]. For binary variables (e.g., presence of complications, clinical success) and categorical variables (e.g., type of effusion, pathological type), contingency tables were generated. Wilcoxon rank-sum tests and Kruskal-Wallis H tests were employed to assess statistical differences among groups. All statistical analyses were performed using R, with a P value <0.05 considered statistically significant.

Results

From January 2023 to September 2024, a total of 576 patients underwent pancreaticoduodenectomy at the Qingchun Campus, including 343 males and 233 females. Among them, 341 patients (59.20%) underwent open surgery and 235 (40.80%) laparoscopic surgery. A total of 125 patients (79 males, 46 females, mean age 66 years, range, 22–86 years) received ultrasound-guided percutaneous drainage postoperatively, including 85 in the open group and 40 in the laparoscopic group. Thirty cases (20 males, 11 females; mean age 67 years, range, 41–83 years) involved fluid collections at challenging sites, with 23 in the open group and 8 in the laparoscopic group. Postoperative pathology was predominantly pancreatic cancer (11 cases, 35.48%), followed by duodenal papillary cancer (10 cases, 32.26%) and cholangiocarcinoma (6 cases, 19.35%). The mean time from surgery to fluid collection detection was 19 days (median 16.0 days; range, 6–84 days).

Among the patients with fluid collections in challenging sites, 24 (77.42%) underwent the transhepatic method, 4 (12.90%) were performed with the hydrodissection method, and 3 (9.68%) were done with the modified trocar technique (Table 1). In the transhepatic approach group, procedure-related complications occurred in 4 cases (16.67%), including mild pain (2 cases), self-limiting hematoma (1 case), and postoperative leukocytosis with fever (1 case). In the hydrodissection group, signs of infection (leukocytosis) were observed in 1 case (25.00%). No complications were observed in the modified cannula technique group. Components of collections: pancreatic fistula in 7 cases (22.58%), abscess in 10 cases (32.26%), hematoma in 5 cases (16.13%), exudative effusion in 9 cases (29.03%). Catheter sizes: 6 F catheter in 1 case (3.22%), 7 F in 5 cases (16.13%), and 8 F in 25 cases (80.65%). No statistically significant differences were observed between the groups. The mean catheter indwelling time for patients with challenging site fluid collections was 16 days (IQR, 3–48 days), with no significant differences between groups. The technical success rate was 100%. The clinical success rate was 83.87% (26/31), with no significant differences in clinical success rates between the groups. The clinically unsuccessful cases underwent a second or even third procedure, with no cases requiring additional surgical intervention for fluid collection.

A total of 4 patients underwent preoperative CEUS to visualize the target area. In addition, post-operative intracatheter contrast imaging was performed in two patients, with catheter repositioning required in one case.

Discussion

Key findings

In the current study, ultrasound-guided percutaneous drainage achieved a 100% technical success rate for fluid collections in challenging sites, with no severe procedure-related complications. The clinical success rate was 83.87%, which significantly reduced the need for secondary surgeries. These results indicate that ultrasound-guided percutaneous drainage is a safe and effective technique for managing postoperative fluid collections in challenging locations.

Strengths and limitations

In the current study, we present three methods of managing collections in challenging locations post pancreaticoduodenectomy. Aims to increase the success rate of drainage and decrease the complications during the procedure. The findings of this study align with expectations; however, limitations must be noted. First, the team subjectively prioritized surgical procedures deemed safer and easier to perform, which could introduce selection bias affecting the objectivity of the results. Second, as this was a single-center study with a limited sample size, further validation with multicenter, large-sample studies is needed.

Comparison with similar researches

For fluid collections lacking straightforward access, the transhepatic approach provides a validated alternative previously documented in the literature and represents the predominant technique in our series. Among 24 patients with postoperative collections managed via this route, one (4.17%) developed minor hemorrhage, affirming its clinical viability when alternative pathways are precluded. Crucially, catheter side holes must reside entirely within the collection cavity to prevent hepatobiliary contamination.

Hydrodissection is primarily used in radiofrequency ablation. It isolates critical structures from target lesions. Similarly, this technique has been applied in CT-guided punctures to create a safe path by displacing vital organs (16,17). Ultrasound-guided hydrodissection enables real-time monitoring. Operators can dynamically adjust needle trajectories to optimize isolation (18). Additionally, it enables the dynamic guidance of the needle tip into the target area, followed by the placement of a guidewire and drainage catheter. This study confirms the safety and efficacy of the technique. No major complications involving vascular or intestinal injuries or damage to other critical organs occurred.

The modified trocar technique centers on retracting the sharp metallic stylet, utilizing its blunted tip to advance the catheter safely into the target zone (12,19). Functioning similarly to surgical blunt dissection, the soft sheath minimizes tissue trauma and prevents injury to vascular, intestinal, or other critical parenchymal organs. However, this method is not effective when passing through structures like the omentum. In our cases, the separations were performed between the liver and the intestine or stomach, resulting in satisfactory outcomes. The possibility of failure due to postoperative adhesions in the abdominal cavity is a known problem.

In our department, the choice of surgical technique depends on the conditions of the patients: if the hepatic-intestinal space allows for needle insertion, the modified trocar technique is preferred. If needle insertion into the hepatic-intestinal space is difficult and the patient has normal liver function and coagulation status, the transhepatic approach is selected. The hydrodissection technique, being the most complex procedure, is reserved as the last option.

CEUS enables real-time hemodynamic visualization of target regions, facilitating diagnostic differentiation of solid organ lesions (e.g., hepatic masses) (20,21). It also has significant value in guiding drainage procedures in challenging locations. Key applications include: (I) target characterization: CEUS delineates non-enhancing regions and adjacent critical vasculature, offering essential procedural guidance (22,23). In our cohort, 4 patients underwent preoperative CEUS for target localization. (II) Catheter verification: when aspiration yields no abnormal fluid, retrograde contrast injection through indwelling catheters confirms position and trajectory. Post-procedural CEUS revealed catheter malposition requiring revision in 1/2 cases.

Conclusions

In conclusion, ultrasound-guided drainage is a safe and effective procedure for managing fluid collections in challenging locations following pancreaticoduodenectomy.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://gs.amegroups.com/article/view/10.21037/gs-2025-278/rc

Data Sharing Statement: Available at https://gs.amegroups.com/article/view/10.21037/gs-2025-278/dss

Peer Review File: Available at https://gs.amegroups.com/article/view/10.21037/gs-2025-278/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-2025-278/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the ethics committee of The First Affiliated Hospital of Zhejiang University School of Medicine (Reg. No. 2025B-0356) and the requirement for informed consent was waived owing to the retrospective nature of the study.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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