Reliability of Tuffier's line evaluated on cadaver specimens.

The aim was to evaluate the reliability of Tuffier's line usually used as sole method to identify lumbar spinous process for a correct needle placement. Fifty-eight cadaver specimens were placed in a lateral position and a flexion in the lumbar spine performed to achieve a neutralization of the lumbar lordosis. The iliac crests were palpated and the lumbar spinous process marked on the intercristal line with a pin; all specimens were dissected and the marked spinous process documented. The center of the L4 spinous process was hit in 24 male (41.38%) and 10 female (17.24%) specimens. In only two female specimens (3.45%), the upper vertebra was reached; a pin placed in L3 was not found in male cadavers. The inferior edge of the L4 spinous process was hit in male 4 times (6.90%) and in female cadavers 12 times (20.69%). In the fifth lumbar spinous process, pins were placed five times in female cadavers (8.62%) and in only one male cadaveric specimen (3.72%). In conclusion, the accuracy of the focused lumbar spinous process depends on the right bedding and the orientation of the given landmarks, so Tuffier's line stays the most important tool for anesthetists if palpation is performed very precisely.