Evaluation of the white test effectiveness for the prevention of bile leakage after liver resection: multicenter randomized controlled study
Executive Summary
This briefing document synthesizes the findings of a multicenter randomized controlled trial (RCT) evaluating the effectiveness of the "White Test"—an intraoperative procedure using fat emulsion to detect bile leaks—in patients undergoing major liver resection. Despite its theoretical potential to identify and seal bile ducts intraoperatively, the study concludes that the White Test provides no statistically significant benefit in preventing postoperative bile leakage.
Critical Takeaways:
Insignificant Clinical Impact: Postoperative bile leakage rates were nearly identical between the study group (7%) and the control group (8.3%), indicating the test does not reduce the incidence of complications.
High Intraoperative Detection Rate: The White Test identified bile leaks in 37.2% of cases, yet this did not translate to improved postoperative outcomes, suggesting many detected leaks may be clinically insignificant.
Safety and Severity: All postoperative leaks recorded in the study were Grade B (requiring intervention but not re-operation).
Future Directions: Researchers recommend investigating alternative methods, particularly Indocyanine Green (ICG) fluorescence, as the White Test failed to demonstrate efficacy in this randomized setting.
Study Overview and Methodology
The study was a multicenter, blind randomized controlled trial conducted between February 2011 and May 2016 across three specialized centers in Russia, Belarus, and Ukraine.
Participant Profiles
Sample Size: 79 patients (33 men, 46 women) were randomized.
Groups: 43 patients in the study group (received the White Test) and 36 patients in the control group.
Inclusion Criteria: Patients undergoing major hepatic resections (resection of three or more segments).
Common Indications: Metastatic colorectal cancer (40%), right hemihepatectomy (54%), and left hemihepatectomy (41.7%).
The White Test Procedure
The White Test is performed after the liver resection and initial cholestasis control:
Catheterization: The biliary tree is catheterized via the cystic or lobular duct stump.
Clamping: The common bile duct is clamped in the supraduodenal portion.
Injection: A fat emulsion (Lipofundin® MCT/LCT 10%) is injected via the catheter.
Visualization: The transected liver surface is monitored for the appearance of white fluid.
Action: Detected leakage sites are stitched, and the test is repeated until the system is tight.
Comparative Analysis of Outcomes
The primary objective was to compare the incidence of postoperative bile leakage (BL) between the two groups.
Intraoperative and Postoperative Results
Nature of Postoperative Leakages
Severity: All observed biliary complications were Grade B according to the International Study Group of Liver Surgery (ISGLS) criteria.
Study Group Characteristics: Represented by fistulas functioning for 18 to 35 days.
Control Group Characteristics: Represented by bilomas diagnosed via CT, requiring percutaneous drainage for 25 to 40 days.
False Negatives: In the study group, 7.4% (2/27) of patients with a negative White Test still developed postoperative bile leakage. Conversely, 6.2% (1/16) of those with a positive White Test developed a leak despite intraoperative sealing.
Analysis of Themes and Evidence
The Paradox of High Intraoperative Detection
The White Test revealed leaks in 37.2% of patients—a rate significantly higher than the 8.3% leakage rate in the control group. This discrepancy suggests two possibilities:
Clinical Insignificance: Many leaks identified by the fat emulsion might have closed spontaneously or remained asymptomatic without intervention.
Artificial Pressure: The process of injecting the emulsion may induce unphysiologically high pressure in the biliary system, causing "leaks" that would not occur under normal physiological conditions.
Complication Impact and Risk Factors
Bile leakage remains the leading specific surgical complication after liver resection, with incidence rates stable between 6.7% and 18.6%. It is associated with:
Prolonged hospital stays (average 52 days vs. 28 days for non-leakage patients).
Increased risks of sub-phrenic abscesses, internal fistulas, and biliary peritonitis.
Risk factors including malignancy, specific resection types (e.g., mesohepatectomy), and operative time.
Alternative Preventative Methods
The document outlines several other techniques used historically to prevent leaks:
Saline Solution Test: Similar to the White Test but uses saline; results have been controversial and often show no significant benefit.
Methylene Blue: Used for leakage testing with some reported success in reducing incidence.
Gas Test: Involves introducing gas into the biliary tree and using ultrasound to detect bubbles; some studies suggest significant improvement in detection.
Indocyanine Green (ICG): A contemporary method using fluorescence and infrared cameras. While retrospective studies showed a reduction to 0% leakage, recent meta-analyses suggest its benefits in preventing leaks specifically may still require prospective verification.
Conclusions and Study Limitations
Final Conclusion of the Trial
The researchers conclude that the White Test does not provide a clinical benefit in preventing postoperative bile leakage after major liver resection. The test is considered less practical for laparoscopic settings and did not demonstrate a statistically significant reduction in complications compared to standard surgical techniques.
Limitations of the Evidence
Sample Size: The study did not reach the planned number of patients (55 per group), which may lead to a Type 2 statistical error (failure to detect a real effect).
Time Frame: The trial was conducted between 2011 and 2016; technological improvements in alternative methods like ICG have progressed significantly since the data collection ended.
Procedure Duration: The White Test added approximately 15 minutes to the operative time, though this was not statistically significant.
Expert Recommendation
The study suggests that while the White Test is safe, its lack of efficacy warrants a shift in focus toward more modern diagnostic tools, specifically ICG fluorescence, which is becoming a standard in high-income countries and is more adaptable to minimally invasive surgery.
