Evaluation of the bony pelvis in classic bladder exstrophy by using 3D-CT: further insights.

OBJECTIVES

To provide a complete look at the bony pelvis in children with classic bladder exstrophy: dimensions, orientation, and relationships.

METHODS

Three-dimensional computed tomography was used in 6 boys and 1 girl, 5 of whom underwent primary closure and 2 who underwent reclosure at 4 and 8 months. These exstrophy pelves (intrapelvic angles and osseous dimensions) were compared with 26 age and sex-matched controls.

RESULTS

The iliac wing angle was 11.4 degrees larger in the classic bladder exstrophy cases. The sacroiliac joint angle was 9.9 degrees more externally rotated in the exstrophy cases. The pelvis was rotated 14.7 degrees in the superoinferior plane in the exstrophy cases. The mean pubic diastasis was 4.2 cm (0.6 cm in controls). The inter-triradiate distance in the patients with classic bladder exstrophy averaged 6.0 cm (4.2 cm in controls).

CONCLUSIONS

These new findings provide a better understanding of the bony pelvis, especially its posterior portion, in patients with classic bladder exstrophy. The results of this study revealed the orientation of the sacroiliac joints to be more externally oriented than previously thought and the pelvis to be rotated inferiorly, a previously unknown observation. Both of these factors will be important in the planning of newer osteotomies and pelvic reconstruction.