Topography of the lumbar sympathetic trunk in normal lumbar spines and spines with spondylophytes

Background. Degenerative processes of the lumbar spine may change the position of the sympathetic trunk which might cause failure of sympathetic blocks owing to inadequate distribution of local anaesthetic. Methods. The retroperitoneal spaces of 56 cadavers [24 males and 32 females; 79 (10) yr] embalmed with Thiel's method were investigated by dissection. The course of the lumbar sympathetic trunk (LST) was documented from the diaphragmatic level to the linea terminalis. Topography of the large vessels and the psoas muscle was documented. In the case of spondylophytes, the location or direction of displacement of the trunk was regarded with special interest. Results. The LST entered the retroperitoneal space at the level of the vertebral body of L2 in 70 of the 112 sides and showed the most consistent relationship with the medial margin of the psoas muscle at intervertebral disc level L2/3. On 11 spines with spondylophytes, the sympathetic trunk was dislocated to the most ventrolateral point of the spondylophyte in 12 cases, in six cases dorsolaterally, and in one case ventromedially. The more the sympathetic chain departed at the vertebral body level, the more the body developed a concavity by loss of height. Conclusions. Spondylophytes influenced the location of the LST and the distribution of the local anaesthetic. The local anaesthetic should wash around the spondylophyte to reach all possible locations of the chain. The medial margin of the psoas muscle was confirmed to be a consistent reference point at intervertebral disc level L2/3.