Randomized comparison of laparoscopic and open lymphadenectomy in pigs

To compare the efficacy of open and laparoscopic lymphadenectomy and validate an objective model of lymph node retrieval using lymphangiography in pigs.

Twenty-five pigs weighing 54-75 lbs were randomly assigned by side to open or laparoscopic pelvic and paraaortic lymphadenectomy. Lymph node yield, quantified by a masked pathologist, operative time, complications, blood loss, and other variables were recorded. Lymphangiography was done, and radiographs were taken before and after lymph node harvesting. Statistical analysis used McNemar test for nominal data and paired Student t test or Wilcoxon signed-rank test for continuous variables.

Lymph node yields were a mean of 11.5 with a standard deviation of 2.8 for open and 15.3 +/- 3.4 nodes for laparoscopic lymphadenectomy (P = .009). Mean operating time was 26.5 +/- 5.3 minutes for open versus 54.9 +/- 23.7 minutes for laparoscopy (P < .01). Mean blood loss was higher for laparoscopic cases, 35 mL for open versus 58 mL for laparoscopic lymphadenectomy (P = .048). The four major complications were evenly distributed between the two procedures. Lymphangiography was successful in 24 of 25 pigs. A total of 243 lymph nodes were identified with equal distribution by side. Lymphangiographic data correlated well with number of lymph nodes retrieved.

In this randomized trial, laparoscopic lymphadenectomy was at least as effective as open lymphadenectomy, although operating time and blood loss were greater. Lymphangiography was a reliable, objective mode for documentation and assurance of lymph node recovery.