Wiltse has described in 1968 an intermuscular lumbar approach with two vertical incisions made at 30 mm each on both sides of the midline. Since 1988, Wiltse recommends to practice a single median incision because of aesthetic arguments and because it avoids potential difficulties in case of iterative surgery. In this paper, the goal of authors was to determine the advantages of two lateral incisions, particularly in term of cutaneous vascularization. This cadaveric study concerned ten specimens. Colored latex was injected into the lumbar segmentary arteries before taking a cutaneous flap. We calculated the mean of the number of vessels injected and cut on the midline, then all the 10 mm on both sides. The goal was to establish a cutaneous cartography, and to determine a zone of less vascular sacrifice. The lumbar skin was vascularized by an arteriolar network which spreads out from the midline. At 30 mm from the midline, the number of cut vessels is statistically less than in the others areas (P < 0.05). At this distance, the small arteries are superficial, fine, and the subcutaneous tissue appears poorly vascularized. The two lateral incisions have the advantage compared to a single median incision of being short, and of allowing a direct access to the muscular plan of cleavage without subcutaneous detachment, with a less pressure retraction. We think that an incision at 30 mm from spinous processes is less noxious for the skin because it is located at the border of two vascular territories, which depend of a median network for one, and a lateral network for the other. These incisions generate technical difficulties, however, when the approach is prolonged with the top of L2/L3, when a lateral and/or central canalar decompression is considered, and finally, in the event of iterative surgery.
