Purpose of the study: The aim of this study was to determine the laparoscopic approach of L5-S1 disk, by preoperative C.T. evaluation.
Material and methods: 30 patients justified tomodensitometry for low back pain or sciatalogy. We added two scan views and a lateral radiologic mode including pubis. We defined several parameters in order to evaluate the "useful" triangle limited by iliac veins and anterior edge of S1 plateau. This surface was divided in discal and vertebral surfaces. We studied also cutaneous projections of axis and usefull zones for discal or transcorporeal approach.
Results: The "usefull" surface was about 6 cm2 (from 0 to 13.12 cm2). The average vertebral surface was 2.58 cm2 and 3.42 cm2 for discal surface. The best cutaneous point for introduction was 3.3 cm from ombilic in transcorporeal approach and 11.3 cm in discal approach.
Discussion: Peroperative C.T. evaluation seems to be more usefull than radiological for preoperative planning. Peroperative radiographical control is not always efficient to prevent foraminal radicular risk.