title: Does C₁ fracture displacement correlate with transverse ligament integrity?
abstract: OBJECTIVE
  The Rule of Spence states that displacement of the C₁ 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 C₁ displacement on CT scans that correspond to transverse ligament disruption.
  
  
  METHODS
  Over four years, consecutive patients with acute C₁ 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 C₁ lateral mass overhang over the C₂ 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).
  
  
  CONCLUSIONS
  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.
authors: Department of Orthopaedic Surgery, Rothman Institute, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107, USA. radcliffk@gmail.com
authors: Kristen E
authors: KE
authors: Radcliff
authors: Marcos A
authors: MA
authors: Sonagli
authors: Luciano M
authors: LM
authors: Rodrigues
authors: Gursukhman S
authors: GS
authors: Sidhu
authors: Todd J
authors: TJ
authors: Albert
authors: Alexander R
authors: AR
authors: Vaccaro
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000473:pathology; D001270:Cervical Atlas / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology; D008022:Ligaments / Q000293:injuries*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016037:Single-Blind Method; D016103:Spinal Fractures / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods
references: J Neurosurg. 1991 Aug;75(2):221-7
references: 2072158
references: Spine (Phila Pa 1976). 1998 Sep 1;23(17):1832-6
references: 9762739
references: J Bone Joint Surg Am. 1991 Jun;73(5):680-91
references: 2045393
references: J Spinal Disord. 1993 Oct;6(5):392-6
references: 8274806
references: J Spinal Disord. 1990 Mar;3(1):19-24
references: 2134407
references: Spine (Phila Pa 1976). 1988 May;13(5):450-2
references: 3187689
references: J Neurosurg Spine. 2005 Apr;2(4):411-7
references: 15871479
references: Spine (Phila Pa 1976). 1991 Oct;16(10 Suppl):S460-5
references: 1801253
references: Orthop Clin North Am. 1986 Jan;17(1):31-44
references: 3945481
references: Spine (Phila Pa 1976). 2007 Mar 1;32(5):593-600
references: 17334296
references: Neurosurgery. 1988 Jul;23(1):31-5
references: 3173661
references: J Neurosurg. 1991 Aug;75(2):213-20
references: 2072157
references: J Bone Joint Surg Am. 1970 Apr;52(3):543-9
references: 5425648
references: Neurosurgery. 2010 Mar;66(3 Suppl):60-7
references: 20173529
references: Radiology. 2005 Mar;234(3):733-9
references: 15734929
references: J Neurosurg. 1989 Jan;70(1):45-9
references: 2909687
references: Spine (Phila Pa 1976). 1991 Oct;16(10 Suppl):S466-73
references: 1801254
references: Spine (Phila Pa 1976). 1992 Nov;17(11):1285-90
references: 1462202
references: Br Med J. 1927 Jul 30;2(3473):153-7
references: 20773317