Operative outcomes and fracture patterns in dysmorphic sacrums

Introduction: Sacral dysmorphism has been previously reported to occur in 30 % to 40 % of adult patients. It has been described by 6 widely accepted parameters on outlet x-ray views of the pelvis: steep alar slope, retained S1 -S2 disk, presence of mamillary bodies, sacralized L5, tongue in groove SI joint, and non-round neural foramina. Studies have focused on the importance of identifying dysmorphism for safe treatment of fractures in pelvises with dysmorphic upper sacral segments. Less is known regarding whether dysmorphism may be protective against trauma. To our knowledge no studies have focused on how dysmorphic sacrums fracture compared to non-dysmorphic (ND) sacrums, and whether operative rates are different.Aims: To assess the rate of operative fixation of sacral fractures between pelvises with dysmorphic and ND sacrums, as well as whether a difference exists in fracture morphology between groups. Design/Methods: This is a retrospective cohort study out of a single level 1 trauma center. Study participants consisted of those sustaining a pelvic ring injury who were 18 years or older in which orthopaedics was consulted, had CT imaging available, and did not have isolated acetabulum fractures. 355 subjects were included of 671 reviewed pelvic ring injuries. Sacrums were deemed dysmorphic if they met at least one of the six dysmorphic features, and it was determined whether they underwent operative intervention. Fracture classifications and patterning were identified on CT imaging. P values were set <0.05.Results: We found that 44 % of inclusions had a dysmorphic sacrum with the most common feature to be a steep alar slope (68 %). 17.17 % of subjects with a ND sacrum underwent treatment versus 16.56 % for dysmorphic sacrums. No statistical difference regarding operative fixation rates was uncovered (p = .879). However, we found a difference in fracture patterns regarding ipsilateral posterior SI joint widening (p = 0.020).Conclusion: Our study suggests that sacral dysmorphism is not protective against operative fixation based on no difference in operative rates between groups. However, our data supports that pelvises with dysmorphic sacrums may fracture differently based on the difference observed regarding other pelvic ring injuries.

Automated summary

This study aims to assess the rate of operative fixation of sacral fractures in pelvises with dysmorphic and nondysmorphic sacrums, as well as whether a difference exists in fracture morphology between groups. The study found no statistical difference in operative fixation rates between pelvises with dysmorphic and nondysmorphic sacrums, but a difference in fracture patterns was observed.