Open AccessDoes C 1 Fracture Displacement Correlate with Transverse Ligament Integrity?
Author(s) -
Radcliff Kristen E,
Sonagli Marcos A,
Rodrigues Luciano M,
Sidhu Gursukhman S,
Albert Todd J,
Vaccaro Alexander R
Publication year - 2013
Publication title -
orthopaedic surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 23
eISSN - 1757-7861
pISSN - 1757-7853
DOI - 10.1111/os.12034
Subject(s) - displacement (psychology) , fracture (geology) , medicine , transverse plane , ligament , structural integrity , orthodontics , anatomy , materials science , structural engineering , composite material , engineering , psychology , psychotherapist
Objective The R ule of S pence states that displacement of the C 1 lateral masses by >6.9–8.1 mm suggests loss of transverse ligament integrity. The purpose of this study was to establish the thresholds of C 1 displacement on CT scans that correspond to transverse ligament disruption. Methods Over four years, consecutive patients with acute C 1 fractures with at least three fracture lines were analyzed. CT measurements and MRI were assessed by blinded observers for bony displacement in the axial (internal and external lateral mass separation), coronal and sagittal planes and transverse ligament integrity. Results Eighteen patients were studied. Mean CT bony measurements were as follows: internal border lateral mass separation ( ILM ) 23.3 ± 3.4 mm, external border lateral mass separation ( ELM ) 50.3 ± 4.3 mm, total C 1 lateral mass overhang over the C 2 superior process ( LMO ) 5.4 ± 1.3 mm. Twelve patients were identified as having intact transverse ligament and six had transverse ligament disruption. There was no difference in mean normalized ILM , ELM , or LMO between patients with or without transverse ligament integrity ( P > 0.05). Conclusion There was no correlation between bony displacement and transverse ligament integrity. CT scans post‐injury may not show the position of maximal displacement. If there is clinical concern about a possible transverse ligament injury, MRI should be performed.