[Morphometric characteristics of the sacrum in Mexican population. Its importance in lumbosacral fusion and fixation procedures].

BACKGROUND

the morphology and the morphometric characteristics of the sacrum and its components determine the size of pedicle implants in both width and length and the orientation of the screw at the time of implantation. The present study aimed to determine the morphometric characteristics of the sacrum in the Mexican population in order to establish safe approaches for the placement and orientation of the screws during lumbosacral instrumentation.

METHODS

morphometric characteristics were determined for 50 dry sacra distributed in 44 measurement parameters (39 linear and 5 angular) divided in five categories: 1) anterior and posterior sacral foramina; 2) S1 vertebral pedicle and intermediate sacral crest; 3) vertebral bodies and the general parameters of the sacrum; 4) S1 superior articular process facet and sacral canal, and 5) S1 pedicle approaches.

RESULTS

the S1 pedicle average length was 25.00 mm ± 2.41, the S1 pedicle anterior and posterior average height was 20.68 mm ± 3.40 and 24.64 mm ± 3.77 respectively, the sacral canal dimensions on its superior opening were 15.13 mm ± 2.40 in the sagital diameter and 31.07 mm ± 2.65 for the transverse diameter, in S1 the anteriomedial screw trajectory average distance was 50.08 mm ± 3.72 with an average angle of 34.30° ± 4.1 from the screw entry point.

CONCLUSION

the results from this study are important for the correct screw placement and position in lumbosacral instrumentation, and also for other procedures that involve the sacral region as a surgical and diagnostic target.