Retroperitoneal lymph node dissection for nonseminomatous testicular tumor. A modified retroperitoneal lymph node dissection for stage I testicular tumor has been described by Weissbach. We have developed a two-step procedure for performing laparoscopic retroperitoneal lymph-adenectomy within these boundaries. In the first step, a ventral approach is used. The colon is dissected free, then the spermatic vein is excised, and the borders of the dissection are defined. Removal of retroaortic and retrocaval nodal tissue is technically not feasible via the ventral approach. Therefore, in the second step, a lateral approach is employed, which is the key to success since it permits easy transection of the lumbar vessels. Thus complete lymph node dissection can be achieved. Between August 1992 and March 1994 this procedure was performed in 15 patients. In nine patients, the tumor was on the right side and in six on the left. Conversion to open surgery was necessary in two patients because of uncontrollable bleeding and a large metastasis, respectively. Microscopic metastases were detected in two other patients. Apart from the above-mentioned bleeding no major complications occurred; no blood transfusion were required. The results obtained so far demonstrate that this procedure is technically feasible. Therefore, we have decided to perform laparoscopic retroperitoneal lymphadenectomy also in patients with stage II B tumors who have received chemotherapy; to date one patient with a left-sided stage II B tumor has been operated on successfully.