Asymmetric Sacral Dysmorphism: Prevalence and Impact on Surgical Planning

Objectives: To determine the prevalence and surgical relevance of asymmetry in patients with sacral dysmorphism. Methods: Design: Retrospective Review Setting: Level one academic trauma center Patient Selection Criteria: Included were patients between 16-85 years old with an operative pelvic ring injury (OTA/AO 61A-C) and a thin-cut pelvis CT (≤2.0mm) with 3D reformats. Sacral dysmorphism was defined by the inability to place a transiliac-transsacral screw in the upper sacral segment. Outcome Measures and Comparisons: Asymmetry was assessed by evaluating side-to-side differences in neuroforaminal height, upper sacral segment pathway obliquity, and anterior-posterior pathway width. Results: The group of patients with asymmetric sacral dysmorphism was 52.9% female while the group with symmetric sacral dysmorphism and without sacral dysmorphism was 36.3% female and 44.3% female, respectively. The average age of the patients with asymmetric, symmetric, and no sacral dysmorphism was 43.0 years (range 16-89), 42.9 years (range 18-94), and 47.5 years (range 33-89), respectively. Of the 220 patients evaluated, there were 114 (51.8%) patients that demonstrated sacral dysmorphism. Among dysmorphic patients, 34 (29.8%) exhibited at least one feature of asymmetry. Asymmetric features included differences in neuroforaminal height, upper sacral segment pathway obliquity, and pathway width. Conclusion: Nearly 30% of patients with sacral dysmorphism demonstrated asymmetric features, which can impact surgical planning. Recognition of asymmetric sacral dysmorphism is important for proper execution of posterior pelvic fixation. Level of Evidence: Level IV.