[Screwing into the pedicles of the lower lumbar spine (L3-L4-L5) and the lumbosacral joint].

In cases in which fixation of the lower lumbar vertebrae by plates is performed, the insertion of screws into the pedicles may be difficult. After an anatomical study the authors conclude that a partial resection of the articular facet of the superior vertebra allows improved insertion of antero-posterior screws in the pedicles. At the level of the fifth lumbar vertebra, the direction of the screws should be 10 degrees downwards. At the level of the sacrum it should be 30 degrees downwards. Screws of 15 mm length can be used in adults.