[Fractures of the L5 transverse process in pelvic ring injury]

The aim of the study was to record the frequency of L5 transverse process fractures associated with pelvic injuries and to find out whether in unstable pelvic fractures the frequency is significantly higher.

The group evaluated comprised 106 patients (38 women and 68 men; average age, 43.4 years; range, 16 to 95 years) treated for pelvic ring fractures at two trauma centres in the period from January 1 to December 31, 2007. Their radiographs and CT scans were retrospectively reviewed in order to identify fractures of the L5 transverse processes and to obtain exact descriptions of injuries to the dorsal pelvic structures. The results were statistically analysed using the Chi-square test with a 5 % level of significance.

The evaluation of radiographs and CT scans identified L5 process fractures in 21 patients; none of these had type A pelvic fracture. An L5 transverse process fracture was found in 10 (15 %) of 69 patients with type B pelvic fracture and in 11 (73 %) of 15 patients with type C pelvic fracture, i.e., only in the patients with unstable injury to the pelvis classified as type C or type B. The occurrence of L 5 transverse process fractures was significantly higher in completely unstable, type C pelvic trauma than in partially unstable, type B pelvic injury (p < 0.001).

Our results showed that evaluation of the radiographs was not sufficient for the identification of L5 transverse process fractures and trauma to the dorsal pelvic structures. The reason was either poor quality or incorrect positioning. This gives support to the recommendations of many authors that CT scans should be the standard method for identification of all pelvic injuries. The study also confirmed that L5 transverse process fractures are associated with unstable pelvic injuries. Their significantly high occurrence is in agreement with other relevant studies which, however, have reported the results without statistical evaluation.

The study shows a significantly higher occurrence of L5 transverse process fractures in patients with unstable pelvic ring injuries. The finding of such a fracture should focus attention to looking for trauma to the dorsal pelvic structures.