Susanna Llido

Analysis of the relationship between the double transverse foramen and the possibility of developing clinical symptoms after whiplash

Currently, there is no information about the possibility of developing clinical symptoms after whiplash in double transverse foramen subjects. Our aim was to test whether subjects with double transverse foramen have an increased risk of presenting with an acute headache, dizziness, vertebral artery dissection, and vomiting after whiplash.We recorded the absence/presence of double transverse foramen, and the absence/presence of neck pain, acute headache, dizziness, vertebral artery dissection, and vomiting in 85 patients who had suffered whiplash injuries in car rear‐end impacts in road traffic accidents. We used the odds ratio test to determine whether double transverse foramen subjects are at a higher risk of developing an acute headache, dizziness, and vomiting than non‐double transverse foramen subjects.Although double transverse foramen subjects presented with more clinical symptoms after whiplash, the odds ratio test revealed that their risks of developing acute headache (P = 0.30), dizziness (P = 0.09), or vomiting (P = 0.18) were not significantly greater than in the control group.Double transverse foramen subjects are not at a higher risk of presenting acute headache, dizziness, vertebral artery dissection, and vomiting after whiplash. Clin. Anat. 30:761–766, 2017.

Cortical bone thickening in Type A posterior atlas arch defects: experimental report

BACKGROUND CONTEXT To date, no information about the cortical bone microstructural properties in atlas vertebrae with posterior arch defects has been reported. PURPOSE To test if there is an increased cortical bone thickening in atlases with Type A posterior atlas arch defects in an experimental model. STUDY DESIGN Micro-computed tomography (CT) study on cadaveric atlas vertebrae. METHODS We analyzed the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry vertebrae with a Type A atlas arch defect and normal control vertebrae. RESULTS The micro-CT study revealed significant differences in cortical bone thickness (p=.005), cortical volume (p=.003), and medullary volume (p=.009) values between the normal and the Type A vertebrae. CONCLUSIONS Type A congenital atlas arch defects present a cortical bone thickening that may play a protective role against atlas fractures.

Unexpected Persistent Dentocentral Synchondrosis of C2

BACKGROUND The persistence of synchondrosis in adulthood can confound diagnostic decisions made during patient management. CASE DESCRIPTION A 59-year-old woman who presented neck pain, acute headache, and acute cervical myelopathy symptoms after suffering whiplash grade 3 in a car rear-end impact underwent a conventional radiologic study that revealed no fracture and no anatomic spine variations. The magnetic resonance imaging study revealed no spinal cord intensity signal changes, but it showed a persistent (remnant) dentocentral synchondrosis that was undetected in a previous conventional radiographic evaluation. CONCLUSIONS The localization and level of the remnant of the dentocentral synchondrosis are extremely important from the clinical viewpoint because of odontoid and C2 fractures. Neurosurgeons should thus be aware of the possible presence of a persistent (remnant) C2 dentocentral synchondrosis in adult subjects in order to avoid misdiagnosis with C2 fracture.

Prevalence of anatomic variations of the atlas vertebra

BACKGROUND CONTEXT The retrotransverse foramen (RTF), arcuate foramen (AF), unclosed transverse foramen (UTF) and posterior atlas arch defects (PAAD) are anatomic variations of the atlas vertebra that surgeons must be aware of before spine surgery is performed. PURPOSE To analyze the prevalence of the AF, RTF, UTF, and PAAD. STUDY DESIGN Ex-vivo anatomical study. PATIENT SAMPLE Two hundred eighteen atlas vertebrae obtained from 100 Caucasian subjects and 118 sub-Saharan African subjects (48 Sotho subjects, 35 Xhosa subjects and 35 Zulu subjects). METHODS We studied 218 atlas vertebrae from skeletons of the Raymond A. Dart Collection in order to analyze the prevalence of AF, RTF, UTF, and PAAD in both Caucasian and sub-Saharan African subjects. OUTCOME MEASURES Not applicable. RESULTS Sixty-nine (31.2%) atlases presented anatomical variants: 64 (29.3%) presented one anatomical variant, 4 (1.8%) presented two, and 1 (0.5%) presented three. AF, RTF, UTF, Type A and Type E defects were present in 35 (16.1%), 17 (7.8%), 17 (7.8%), 5 (2.3%), and 1 (0.5%) vertebrae, respectively. The vertebrae with two anatomical variants presented a bilateral UTF and a Type A defect, a bilateral AF and a Type A defect, a right UTF and a left AF, and a right UTF and a Type E defect. The vertebra with three anatomical variants presented a bilateral RTF, a left UTF, and a left AF. No sex differences in prevalence of the RTF (p=.775), AF (p=.605), UTF (p=.408) and Type A defects (p=1.000) were found in the sub-Saharan African and Caucasian groups (RTF, p=.306; AF, p=.346; UTF, p=.121; Type A defects, p=.561). Comparison between the sub-Saharan African (all subjects) and the Caucasian group revealed no differences in the UTF (p=.105), AF (p=.144), RTF (p=.542) and Type A defects (p=.521) prevalence. Also, no differences in the prevalence of the UTF (p=.515), AF (p=.278), and RTF (p=.857) between Zulu, Xhosa and Sotho subjects were found. Neither were found sex differences in the prevalence of UTF, RTF and AF in Zulu (p=.805, p=.234, p=.129), Xhosa (p=.269, p=.181, p=.309), and Sotho subjects (p=.062, p=.590, p=.106). CONCLUSIONS The present study has revealed no sex differences in the prevalence of AF, UTF, RTF or PAAD in both Caucasian and sub-Saharan African subjects. This research has also indicated no differences in the prevalence of the UTF, AF and RTF between Zulu, Xhosa and Sotho subjects. In addition, this study has revealed no differences in the Type A, UTF, AF, and RTF prevalence between the sub-Saharan African (all subjects) and the Caucasian subjects. These variations may be known by surgeons before spine surgery for better planning.

Can the transverse foramen/vertebral artery ratio of double transverse foramen subjects be a risk for vertebrobasilar transient ischemic attacks?

The C6 is the cervical vertebra into which the vertebral artery enters the passage of the transverse foramen and it is the vertebra most affected by double transverse foramina. There is currently little information about the relation between the vertebral artery and the double transverse foramen in C6. We aimed to test whether subjects with a double transverse foramen in C6 have a reduced transverse foramen/vertebral artery ratio when compared with normal anatomy subjects who possess a single transverse foramen which may be a risk for transient vertebral artery stenosis. We measured the area of the transverse foramen and the vertebral artery in 27 double transverse and 56 normal anatomy subjects using computed tomography angiography. We found significant differences in the area of the transverse foramen between double transverse and normal subjects (P < 0.001) but not between the vertebral artery area of double transverse and normal subjects (P = 0.829). The subjects with double transverse foramina have a reduced transverse foramen/vertebral artery ratio, which may be a possible risk for transient vertebral artery stenosis.

Congenital posterior atlas arch defects

We read with interest the recently published manuscript by Jin et al. [1]. The authors analyzed the hypertrophy of the anterior arch of the atlases with ‘‘congenital nonunion of the posterior arch.’’ However, the authors failed to mention the article by Currarino et al. [2]. In that article, the authors proposed an anatomical classification of the posterior atlas arch defects in five groups: Type A, small posterior midline gap as a result of failure of posterior fusion of the two lateral ossification centers; Type B, unilateral clefts, ranging from a small defect to complete absence of one hemiarch; Type C, bilateral defects with preservation of the most dorsal part of the arch; Type D, absence of the posterior arch with a persistent posterior tubercle; and Type E, complete absence of the posterior arch and tubercle. Thus, we believe it would be better if Jin et al. [1] mentioned that they analyzed Type A posterior atlas arch defects in their manuscript. The main problem about these defects is that it is more difficult than expected to differentiate dry atlas arch defects from fractures, even in postmortem studies [3], and that misdiagnosis between fractures and congenital atlas arch defects has been described before [4]. In this context, one of the most exciting findings of the manuscript by Jin et al. [1] was the description of an anterior arch stress fracture with a posterior Type A defect in the same patient. However, the authors should consider the possibility of the presence of an anterior arch defect and a posterior Type A defect in the same atlas because Guenkel et al. [5], in a study carried out on 1,609 subjects, found two cases of bipartite spondyloschisis. Moreover, Petre et al. [6] described the case of a 16-year-old football player who sustained a flexion compression injury during a game. The player was initially diagnosed with a C1 fracture and treated with a rigid cervical collar. Nevertheless, weeks later, the final diagnosis was congenital nonfusion of the posterior arch of C1 and congenital nonfusion/fibrous nonunion of the anterior arch of C1, but no traumatic abnormalities. Thus, as Jin et al. [1] carried out a retrospective review of computed tomography cervical spine studies, it is plausible that they observed an anterior arch defect and a posterior Type A defect in the same atlas, misdiagnosed as an anterior arch stress fracture with a posterior Type A defect. This is why we recommend that suspected anterior atlas arch stress fractures be definitively diagnosed after comparing initial image studies with others performed several weeks after the initial diagnosis.