Morphometric analyses of the cervical superior facets and implications for facet dislocation

Abstract

The articular facets of the cervical spine have been well addressed; however, little information is available on the relationship of the superior facets of the cervical spine to traumatic dislocation in the literature. Morphometric analyses of the superior facets of 30 dried cervical spines from C3 to C7 were performed to determine any morphological differences. The angle of the superior facet with respect to the transverse plane was also measured on computed tomography (CT) scans of 30 patients having neck injury without fracture/dislocation. The vertical and surface lengths of the superior facet were significantly lower (P<0.01) at C6-C7 levels than at C3-5 levels. The anteroposterior diameter of the superior facet was smaller (P<0.05) at C6 and C7 levels compared to C3-5 levels. Although the superior facet joint surface is in a more coronal orientation in lower cervical vertebrae, the inclination of the superior facet is more horizontal relative to the transverse plane when measured in vivo. A combination of lower height, smaller anteroposterior diameter of the superior facet, and a more horizontally oriented superior facet at C6 and C7 levels in vivo may explain the predilection of translation relative to one another in the lower cervical spine. Résumé Les facettes articulaires de la colonne cervicale sont bien analysées cependant une meilleure connaissance des relations de l'articulaire supérieure lors des traumatismes avec luxations de la colonne dans la littérature est possible. L'analyse morphométrique de l'articulaire supér-ieure a été analysée sur 30 colonnes cervicales de cadavres, de C3 à C7, de façon à analyser les différences morphologiques. L'angle supérieur de l'articulaire a été mesuré sur le scanner de 30 patients ayant présenté un traumatisme cervical sans fracture, ni luxation. Les dimensions verticales et les surfaces de l'articulaire supérieure sont, significativement, moins importantes au niveau C6 et C7 qu'au niveau C3 à C5 (p<0.01). Le diamètre antéropostér-ieur de l'articulaire supérieure est également plus petit au niveau de C6 C7 qu'au niveau de C3 C5 (p<0.05). De la même façon, l'articulaire supérieure est dans un plan plus frontal dans la partie basse de la colonne. L'inclinaison de cette articulaire est, de même, plus horizontale par rapport au plan transversal, mesure in vivo. La combinaison de tous ces facteurs : dimensions moins importantes, petits diamètres, antéropostérieur et facettes supérieures de l'articulaire plus horizontale en C6 C7, expliquent la fréquence des translations relatives possibles des vertèbres dans la partie basse de la colonne et donc la fragilité de cette zone.

Morphometric Study of Cervical Vertebrae C3-C7 in a Population from Northeastern Mexico

“…Transfacet fixation has infrequently been used for cervical column stabilization (Liu et al, 2008), even though it has been shown to carry a smaller risk of nerve root injury (Liu et al, 2006), which is why it should be considered as an alternative to transpedicular fixation (Liu et al, 2008;Jones et al, 1997). Ebraheim et al (2008) reported a decrease in vertical length from C3-C7 of the superior articular facets, with no significant difference by gender or side. On the other hand, we observed a progressive decrease from C3-C6.…”

“…It is thought that orientation and size of articular facets are related to the luxation of the articulation. This luxation is most commonly present at C5-C6 when unilateral and at C6-C7 when bilateral (Ebraheim et al, 2008).…”

“…Morphometric studies of the cervical, thoracic, and lumbar vertebrae have been conducted (Abuzayed et al;Kayalioglu et al;Pal & Routal, 1986;Olsewski et al, 1990;Hou et al, 1993;Ebraheim et al, 1996;Pal & Routal, 1996;Christodolou et al, 2005;Liau et al, 2006;Ebraheim et al, 2008;Urrutia-Vega et al, 2009), and the majority of these studies highlight the importance of such studies in the development of vertebral column instrumentation (UrrutiaVega et al; Ebraheim et al, 1996;Olsewski et al). These studies have used diverse techniques to obtain the vertebral column measurements, among which the following are notable: CT scan (Abuzayed et al; Sieradzki et al; Yusof et al), cadaveric studies (Kayalioglu et al, 2007), radiography (Sieradzki et al) and fluoroscopy (Urrutia-Vega et al).…”

“…The majority of the studies focus on the pedicle, because this is the site where vertebral column fixation procedures are most frequently implemented. Only a few of the studies describe the characteristics of the remaining elements that comprise the vertebra (Pal & Routal, 1986;Pal & Routal, 1996;Winkelstein et al, 2001;Ebraheim et al, 2008).…”

Cervical Spine Motion During Football Equipment-Removal Protocols: A Challenge to the All-or-Nothing Endeavor

“…Although pure rotation without linear translation can occur at the proximal end of the chain in the atlanto-occipital joint, which acts as a hinge due to the depth of the atlantal sockets, 15 the presence of translations indicates movement of the cervical vertebrae. Small translations without rotation can occur between vertebrae, primarily at the distal end of the chain (C5-7), 16 but these are extremely small compared with the translation of the head relative to the torso when the cervical chain (C1-7) moves collectively in the sagittal plane (ie, cervical spine flexion-extension). We did not attempt to statistically analyze differences among the limited number of ATs, but the separated but parallel lines in the angular variables suggested small variations in atlanto-occipital manipulation by each AT (Figures 2A and 3A).…”