['To analyze whether primary metastatic spread occurs behind the lumbar vessels and whether removal is necessary for accurate staging in diagnostic retroperitoneal lymph node dissection, because dissection of lymphatic tissue behind the lumbar vessels is a challenging maneuver.', 'One hundred thirty-nine patients were included in our study. Twenty-nine patients with clinical Stage I tumor underwent laparoscopic staging lymph node dissection, including removal of the lymph nodes behind the lumbar vessels. Sixty-four patients with Stage II testicular cancer were retrospectively examined by computed tomography to determine the localization of the enlarged lymph nodes in relation to the lumbar vessels. On the basis of these results, 49 patients with clinical Stage I underwent laparoscopic lymph node dissection within the same template but without dissection of the lymphatic tissue behind the lumbar vessels.', 'In the first group, 10 of 29 patients had pathologic Stage IIA tumors, with positive nodes exclusively ventral to the lumbar vessels. In group 2, 39 patients with solitary metastatic lesions had enlarged lymph nodes, which were always ventral to the lumbar vessels. Only in 3 of 25 patients with multiple metastases was one enlarged node found behind the lumbar vessels. In group 3, no tumor recurrence either before or behind the lumbar vessels could be found in 46 patients after a mean follow-up of 27.8 months.'] Does primary lymphatic metastatic spread in testicular cancer occur ventral to the lumbar vessels?