1. Alker GJ Jr , Oh YS , Leslie EV : High cervical spine and craniocervical junction injuries in fatal traffic accidents: a radiological study. Orthop Clin North Am 9 : 1003 – 1010 , 1978 Alker GJ Jr, Oh YS, Leslie EV: High cervical spine and craniocervical junction injuries in fatal traffic accidents: a radiological study. Orthop Clin North Am 9: 1003–1010, 1978 2. Blackwood NJ : Atlo-occipital dislocation. A case of fracture of the atlas and axis, and forward dislocation of the occiput on the spinal
Iman Feiz-Erfan, L. Fernando Gonzalez and Curtis A. Dickman
L. Fernando Gonzalez, Neil R. Crawford, Robert H. Chamberlain, Luis E. Perez Garza, Mark C. Preul, Volker K. H. Sonntag and Curtis A. Dickman
Object. The authors compared the biomechanical stability resulting from the use of a new technique for occipitoatlantal motion segment fixation with an established method and assessed the additional stability provided by combining the two techniques.
Methods. Specimens were loaded using nonconstraining pure moments while recording the three-dimensional angular movement at occiput (Oc)—C1 and C1–2. Specimens were tested intact and after destabilization and fixation as follows: 1) Oc—C1 transarticular screws plus C1–2 transarticular screws; 2) occipitocervical transarticular (OCTA) plate in which C1–2 transarticular screws attach to a loop from Oc to C-2; and (3) OCTA plate plus Oc—C1 transarticular screws.
Occipitoatlantal transarticular screws reduced motion to well within the normal range. The OCTA loop and transarticular screws allowed a very small neutral zone, elastic zone, and range of motion during lateral bending and axial rotation. The transarticular screws, however, were less effective than the OCTA loop in resisting flexion and extension.
Conclusions. Biomechanically, Oc—C1 transarticular screws performed well enough to be considered as an alternative for Oc—C1 fixation, especially when instability at C1–2 is minimal. Techniques for augmenting these screws posteriorly by using a wired bone graft buttress, as is currently undertaken with C1–2 transarticular screws, may be needed for optimal performance.
L. Fernando Gonzalez, David Fiorella, Neil R. Crawford, Robert C. Wallace, Iman Feiz-Erfan, Denise Drumm, Stephen M. Papadopoulos and Volker K.H. Sonntag
indicates a craniocervical junction injury and should direct attention to both the atlantooccipital and atlantoaxial articulations. Based on cervical spine radiographs with no correction for magnification issues, Lee, et al., 11 reported that the normal BDI ranged between 2 and 15 mm in adults. This range is slightly greater than that observed in our normative population based on CT scans. Because CT scanning is more accurate than plain radiography, the current data may be more accurate than those previously reported. Consequently, BDI values greater than 9 mm (derived
Nicholas C. Bambakidis, Iman Feiz-Erfan, Eric M. Horn, L. Fernando Gonzalez, Seungwon Baek, K. Zafer Yüksel, Anna G. U. Brantley, Volker K. H. Sonntag and Neil R. Crawford
vertebral coordinate systems using a digitizing probe. Technical note . Spine 22 : 559 – 563 , 1997 6 Crawford NR , Hurlbert RJ : Anatomy and biomechanics of the craniocervical junction . Semin Neurosurg 13 : 101 – 110 , 2002 7 Crawford NR , Peles JD , Dickman CA : The spinal lax zone and neutral zone: measurement techniques and parameter comparisons . J Spinal Disord 11 : 416 – 429 , 1998 8 Crawford NR , Yamaguchi GT , Dickman CA : A new technique for determining 3-d joint angles: the tilt/twist method . Clin Biomech (Bristol