Open versus laparoscopic retroperitoneal lymph node dissection: assessing adequacy of dissection in a porcine model

Laparoscopic retroperitoneal lymph node dissection (L-RPLND) is emerging as a viable alternative to traditional open retroperitoneal lymph node dissection (O-RPLND). Despite numerous reports confirming clinical oncologic equivalency between the two approaches, however, concerns still remain over the adequacy of laparoscopic dissection. We therefore sought to compare the completeness of dissection between O-RPLND and L-RPLND in a porcine model.

Fourteen domestic swine were divided into two equivalent groups. Both groups underwent bilateral retroperitoneal lymph node dissection, approximating templates used in human dissection. In one group, the procedure was performed through an open midline incision, while the other group underwent completely laparoscopic dissection. Tissue was independently analyzed by a pathologist, who recorded lymph node yield based on microscopic evaluation.

All animals in the L-RPLND group underwent successful procedures, without the need for conversion. Two open procedures were aborted because of hemorrhage. Mean lymph node yield from O-RPLND was 32, while the mean yield for L-RPLND was 29. This difference was not statistically significant (P=0.65).

In the porcine model, L-RPLND is capable of providing a quality of dissection equivalent to that of O-RPLND, in terms of absolute lymph node yield on microscopic examination. The applicability of this data to human patients, however, may be limited by significant anatomic differences between the human and the pig. Further prospective comparison in human patients is critically needed.