Hox genes in mouse and human with their phylogenetic counterparts in Drosophila ; 39 Hox genes are involved in the mouse and human vertebral column, found in four clusters of Hox A, B, C and D on four chromosomes (6, 11, 15 and 2), designated by Arabic numbers within each cluster and arranged as paralogues, so that the lower numbered Hox paralogues such as Hox a-1 and Hox d-1 are located on the anterior 3 ′ position of the chromosomes, and the higher numbered paralogues such as Hox a-13 and Hox d-13 are on the 5 ′ 

Hox genes in mouse and human with their phylogenetic counterparts in Drosophila ; 39 Hox genes are involved in the mouse and human vertebral column, found in four clusters of Hox A, B, C and D on four chromosomes (6, 11, 15 and 2), designated by Arabic numbers within each cluster and arranged as paralogues, so that the lower numbered Hox paralogues such as Hox a-1 and Hox d-1 are located on the anterior 3 ′ position of the chromosomes, and the higher numbered paralogues such as Hox a-13 and Hox d-13 are on the 5 ′ 

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Background The embryology of the bony craniovertebral junction (CVJ) is reviewed with the purpose of explaining the genesis and unusual configurations of the numerous congenital malformations in this region. Functionally, the bony CVJ can be divided into a central pillar consisting of the basiocciput and dental pivot and a two-tiered ring revolving...

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Context 1
... primary segmentation, the determination of the positional identity of the prevertebral segments along the embryonic axis, which in turn ordains the regional developmental specifications of the vertebral phenotypes, is controlled by Hox genes. The mammalian Hox genes encode transcription factors used in regulat- ing the establishment of the body plan. They contain the phylogenetically highly conserved homeobox domain [24, 42, 43]. In mouse and humans, there are 39 Hox genes distributed in four linkage clusters, Hox A, B, C, and D, on four different chromosomes (chromosomes 6, 11, 15, and 2) ( Fig. 19). The members of each cluster, designated by Arabic numerals, are also grouped verti- cally along the clusters because analogous members of each group are linked by common origin from a single ancestral gene, so that Hox a 4 , b 4 , c 4 , and d 4 are connected to the same phylogenetic origin and are called paralogues (Fig. 19). The lower numbered paralogues are located on the anterior 3 ′ axis of the chromosome and the higher numbered ones are on its posterior 5 ′ locations (Fig. 19). Hox genes are expressed in mesodermal and ectoder- mal cells along the body axis. Each gene has a characteristic and distinct anterior boundary of expres- sion. A temporal and structural colinearity exists between the position of a gene in a cluster and its expression pattern. Thus, genes from the more anterior 3 ′ locations in the Hox clusters are expressed earlier and always occupy more anterior (cranial) expression domains than genes closer to the posterior 5 ′ location in the clusters (Fig. 19). For example, Hox a-3 has a more anterior expression domain than Hox a-9 and similarly between Hox d-4 and Hox d-10 . Functionally, only the anterior boundary of the Hox expression is important. Since multiple genes have the same anterior expression boundary along the prevertebral axis, each metameric segment can be identified by its own characteristic combination of Hox gene expression domains, i.e. its own Hox code (Fig. 20). A specific Hox code acts as a master switch in determining the exact positional identity of a mesodermal segment along the body axis, and via regional idiosyncrasies in development, ...
Context 2
... primary segmentation, the determination of the positional identity of the prevertebral segments along the embryonic axis, which in turn ordains the regional developmental specifications of the vertebral phenotypes, is controlled by Hox genes. The mammalian Hox genes encode transcription factors used in regulat- ing the establishment of the body plan. They contain the phylogenetically highly conserved homeobox domain [24, 42, 43]. In mouse and humans, there are 39 Hox genes distributed in four linkage clusters, Hox A, B, C, and D, on four different chromosomes (chromosomes 6, 11, 15, and 2) ( Fig. 19). The members of each cluster, designated by Arabic numerals, are also grouped verti- cally along the clusters because analogous members of each group are linked by common origin from a single ancestral gene, so that Hox a 4 , b 4 , c 4 , and d 4 are connected to the same phylogenetic origin and are called paralogues (Fig. 19). The lower numbered paralogues are located on the anterior 3 ′ axis of the chromosome and the higher numbered ones are on its posterior 5 ′ locations (Fig. 19). Hox genes are expressed in mesodermal and ectoder- mal cells along the body axis. Each gene has a characteristic and distinct anterior boundary of expres- sion. A temporal and structural colinearity exists between the position of a gene in a cluster and its expression pattern. Thus, genes from the more anterior 3 ′ locations in the Hox clusters are expressed earlier and always occupy more anterior (cranial) expression domains than genes closer to the posterior 5 ′ location in the clusters (Fig. 19). For example, Hox a-3 has a more anterior expression domain than Hox a-9 and similarly between Hox d-4 and Hox d-10 . Functionally, only the anterior boundary of the Hox expression is important. Since multiple genes have the same anterior expression boundary along the prevertebral axis, each metameric segment can be identified by its own characteristic combination of Hox gene expression domains, i.e. its own Hox code (Fig. 20). A specific Hox code acts as a master switch in determining the exact positional identity of a mesodermal segment along the body axis, and via regional idiosyncrasies in development, ...
Context 3
... primary segmentation, the determination of the positional identity of the prevertebral segments along the embryonic axis, which in turn ordains the regional developmental specifications of the vertebral phenotypes, is controlled by Hox genes. The mammalian Hox genes encode transcription factors used in regulat- ing the establishment of the body plan. They contain the phylogenetically highly conserved homeobox domain [24, 42, 43]. In mouse and humans, there are 39 Hox genes distributed in four linkage clusters, Hox A, B, C, and D, on four different chromosomes (chromosomes 6, 11, 15, and 2) ( Fig. 19). The members of each cluster, designated by Arabic numerals, are also grouped verti- cally along the clusters because analogous members of each group are linked by common origin from a single ancestral gene, so that Hox a 4 , b 4 , c 4 , and d 4 are connected to the same phylogenetic origin and are called paralogues (Fig. 19). The lower numbered paralogues are located on the anterior 3 ′ axis of the chromosome and the higher numbered ones are on its posterior 5 ′ locations (Fig. 19). Hox genes are expressed in mesodermal and ectoder- mal cells along the body axis. Each gene has a characteristic and distinct anterior boundary of expres- sion. A temporal and structural colinearity exists between the position of a gene in a cluster and its expression pattern. Thus, genes from the more anterior 3 ′ locations in the Hox clusters are expressed earlier and always occupy more anterior (cranial) expression domains than genes closer to the posterior 5 ′ location in the clusters (Fig. 19). For example, Hox a-3 has a more anterior expression domain than Hox a-9 and similarly between Hox d-4 and Hox d-10 . Functionally, only the anterior boundary of the Hox expression is important. Since multiple genes have the same anterior expression boundary along the prevertebral axis, each metameric segment can be identified by its own characteristic combination of Hox gene expression domains, i.e. its own Hox code (Fig. 20). A specific Hox code acts as a master switch in determining the exact positional identity of a mesodermal segment along the body axis, and via regional idiosyncrasies in development, ...
Context 4
... primary segmentation, the determination of the positional identity of the prevertebral segments along the embryonic axis, which in turn ordains the regional developmental specifications of the vertebral phenotypes, is controlled by Hox genes. The mammalian Hox genes encode transcription factors used in regulat- ing the establishment of the body plan. They contain the phylogenetically highly conserved homeobox domain [24, 42, 43]. In mouse and humans, there are 39 Hox genes distributed in four linkage clusters, Hox A, B, C, and D, on four different chromosomes (chromosomes 6, 11, 15, and 2) ( Fig. 19). The members of each cluster, designated by Arabic numerals, are also grouped verti- cally along the clusters because analogous members of each group are linked by common origin from a single ancestral gene, so that Hox a 4 , b 4 , c 4 , and d 4 are connected to the same phylogenetic origin and are called paralogues (Fig. 19). The lower numbered paralogues are located on the anterior 3 ′ axis of the chromosome and the higher numbered ones are on its posterior 5 ′ locations (Fig. 19). Hox genes are expressed in mesodermal and ectoder- mal cells along the body axis. Each gene has a characteristic and distinct anterior boundary of expres- sion. A temporal and structural colinearity exists between the position of a gene in a cluster and its expression pattern. Thus, genes from the more anterior 3 ′ locations in the Hox clusters are expressed earlier and always occupy more anterior (cranial) expression domains than genes closer to the posterior 5 ′ location in the clusters (Fig. 19). For example, Hox a-3 has a more anterior expression domain than Hox a-9 and similarly between Hox d-4 and Hox d-10 . Functionally, only the anterior boundary of the Hox expression is important. Since multiple genes have the same anterior expression boundary along the prevertebral axis, each metameric segment can be identified by its own characteristic combination of Hox gene expression domains, i.e. its own Hox code (Fig. 20). A specific Hox code acts as a master switch in determining the exact positional identity of a mesodermal segment along the body axis, and via regional idiosyncrasies in development, ...

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... Hox genes are critical regulators of the organization and morphology of the vertebral elements in vertebrates. 20 For example, inactivation of Hoxd3 in mice is known to produce occiputaxis assimilation, whereas rostral extension of the expression domain of Hoxd4 leads to premature disjunction of the occipital bone, with subsequent "cervicalization of the clivus." 20 Previous work in mice by Boulet and Capecchi 21 demonstrated that homozygous disruption of Hoxc4 creates abnormal vertebral kyphosis in the high thoracic spine area in a process described by Matsuoka et al. 22 as follows: "Neural crest anchors the head onto the anterior lining of the shoulder girdle, while a Hox gene-controlled mesoderm links trunk muscles to the posterior neck and shoulder skeleton." ...
Article
OBJECTIVE Inherited variants predisposing patients to type 1 or 1.5 Chiari malformation (CM) have been hypothesized but have proven difficult to confirm. The authors used a unique high-risk pedigree population resource and approach to identify rare candidate variants that likely predispose individuals to CM and protein structure prediction tools to identify pathogenicity mechanisms. METHODS By using the Utah Population Database, the authors identified pedigrees with significantly increased numbers of members with CM diagnosis. From a separate DNA biorepository of 451 samples from CM patients and families, 32 CM patients belonging to 1 or more of 24 high-risk Chiari pedigrees were identified. Two high-risk pedigrees had 3 CM-affected relatives, and 22 pedigrees had 2 CM-affected relatives. To identify rare candidate predisposition gene variants, whole-exome sequence data from these 32 CM patients belonging to 24 CM-affected related pairs from high-risk pedigrees were analyzed. The I-TASSER package for protein structure prediction was used to predict the structures of both the wild-type and mutant proteins found here. RESULTS Sequence analysis of the 24 affected relative pairs identified 38 rare candidate Chiari predisposition gene variants that were shared by at least 1 CM-affected pair from a high-risk pedigree. The authors found a candidate variant in HOXC4 that was shared by 2 CM-affected patients in 2 independent pedigrees. All 4 of these CM cases, 2 in each pedigree, exhibited a specific craniocervical bony phenotype defined by a clivoaxial angle less than 125°. The protein structure prediction results suggested that the mutation considered here may reduce the binding affinity of HOXC4 to DNA. CONCLUSIONS Analysis of unique and powerful Utah genetic resources allowed identification of 38 strong candidate CM predisposition gene variants. These variants should be pursued in independent populations. One of the candidates, a rare HOXC4 variant, was identified in 2 high-risk CM pedigrees, with this variant possibly predisposing patients to a Chiari phenotype with craniocervical kyphosis.
... 4,5 Bergmann's ossicle, also referred to in the human literature as persistent ossiculum terminale or os terminale, is believed to be a developmental anomaly associated with the odontoid process. 6 This anomaly in humans is considered a benign clinical finding and most often does not warrant further investigation if it is isolated in its occurrence. 7,8 The clinical significance of the persistent ossiculum terminale is limited by the fact that this outgrowth remains attached to the main part of the odontoid process by fibrous tissue. ...
Article
Abstract Anecdotally, during the review of CT and MRI studies of canine patients including the cranial cervical spine, authors have identified a small osseous structure between the atlas (C1) and axis (C2) with no relevant clinical signs. This structure appeared comparable to a “persistent ossiculum terminale” in humans. The aim of this retro- spective, multi-center, case series study was to describe the CT and MRI features of presumed persistent ossiculum terminale in a group of dogs presented with unre- lated medical conditions. Two databases (the imaging database of the teleradiology service VetCT Specialists and the clinical database of the University of Vienna) were scrutinized by different approaches. Medical records of dogs that underwent imaging investigation (CT and/or MRI) that included the atlanto-axial junction were reviewed. Data collected included signalment, sex, breed, age, presenting symptoms, and final diagnosis. Eighteen dogs met the inclusion criteria. Mean age was 85 months (6–166) and breed variation was present. A total of 20 imaging studies were evaluated: CT was performed in 17 dogs; MRI in three dogs; two dogs had both MRI and CT performed. In all cases the presence of at least one small osseous body on the cranial aspect of the odontoid process compatible with a persistent ossiculum terminale was identified as a possible incidental finding without any overt clinical implications. Findings indicated that a small osseous body on the cranial aspect of the odontoid process (presumed persistent ossiculum terminale) in CT and MRI studies may be present in dogs with no clinical signs of neurologic disease.
... The ontogenesis of FM has been described from various perspectives [25,26]. Embryologic data explain how the sclerotomic primordia, involved in the formation of FM, derive from the caudal part of the 4th and rostral part of the 5th somites [27]. During resegmentation, they form the proatlas sclerotome, which gives origin to three elements of the occipital bone: basiocciput, exoocciput, and supraocciput, separated by the anterior and posterior interoccipital synchondroses and undergoing the intramembranous and endochondral ossification [26,28,29]. ...
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... The malformation complex of the craniocervical junction are of great concern to physicians and spine surgeons [9]. Craniocervical instability/deformity could initiate serious fatal/morbid outcome for children, especially if vigorous physical therapy is to be organised [10]. The clinical appearance of children with cranio-cervical abnormalities is usually seen in a long list of syndromic entities such as Goldenhar syndrome [11]. ...
... Most of the congenital abnormalities encountered in the cervical spine involve the atlanto-axial segments. Vertebral synchondrosis are highly hazardous, because of their fragility, fractures and or dislocations can occur in connection with minute trauma [9][10][11]. ...
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Purpose: Torticollis is not of uncommon occurrence in orthopaedic departments. Various theories and studies concerning the pathogenesis of the deformity have been suggested. We aimed to highlight and discuss the underlying cervical and spine malformation complex in correlation with torticollis via radiographic and tomographic analysis and its connection with a specific syndromic entity. Methods: Torticollis has been recognised in six patients (2 boys and 4 girls with an age range of 14-18 years), in addition to a couple of parents manifested persistent backpain. A variable spine malformation complex was the main reason behind torticollis. In addition, some patients manifested plagiocephaly, facial asymmetry and scoliosis/kyphoscoliosis. In some patients, conventional radiographs were of limited value because of the overlapping anatomical structures. Three-dimensional reconstruction CT scanning was the modality of choice, which enlightens the path for the phenotypic characterisation. Results: A 16-year-old-boy presented with torticollis in correlation with pathologic aberration of the spine cartilaginous stage was analysed via 3DCT scan. Comprehensive clinical and radiological phenotypes were in favour of spondylomegepiphyseal dysplasia. The genotype showed a mutation of the NKX3-2 (BAPX1) gene compatible with the diagnosis of spondylo-meg-epiphyseal-metaphyseal dysplasia. His younger male sibling and parents were heterozygous carriers. In two patients with pseudoachondroplasia syndrome, in which odontoid hypoplasia associated with cervical spine synchondrosis causing life-threatening torticollis, Cartilage oligomeric matrix protein (COMP) gene mutation was identified. MURCS syndrome has been diagnosed in two unrelated girls. Torticollis associated with cervical kyphosis was the major presentation since early childhood. Interestingly, one girl showed omovertebral bones of the lower cervical and upper thoracic spine. Her karyotype manifested a balanced translocation of 46 XX, t (14q; 15q). Conclusion: To detect the underlying etiological diagnosis of torticollis, a skeletal survey was the primary diagnostic tool. Conventional radiographs of the craniocervical junction and spine resulted in confusing readings because of the overlapping anatomical structures. Cranio-cervical malformation complex could have serious neurological deficits, especially for children with indefinite diagnosis of torticollis. The widely used term of congenital muscular torticollis resulted in morbid or mortal consequences. Moreover, some patients received vigorous physical therapy on the bases of muscular torticollis. Sadly speaking, this resulted in grave complications. Understanding the imaging phenotype and the genotype in such patients is the baseline tool for precise and proper management. The value of this paper is to sensitise physicians and orthopaedic surgeons to the necessity of comprehensive clinical and radiological phenotypic characterisations in patients with long term skeletal pathology.
... Malformations of the craniovertebral junction are varied and reflect the complexity of its embroyogenesis. Basically, the formation of the craniovertebral junction involves the fourth occipital somite and the first three cervical somites, and is under the control the Hox and Pax genes [6]. After resegmentation, a sclerotome-called the proatlas-is formed from the caudal half of the fourth occipital somite and the cranial half of the fifth somite (first cervical somite) [6]. ...
... Basically, the formation of the craniovertebral junction involves the fourth occipital somite and the first three cervical somites, and is under the control the Hox and Pax genes [6]. After resegmentation, a sclerotome-called the proatlas-is formed from the caudal half of the fourth occipital somite and the cranial half of the fifth somite (first cervical somite) [6]. Under normal human conditions, the hypochordal arch of the fourth somite never fuses with the center of the fifth somite and further partially regresses [8]. ...
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Purpose Atlas-duplication is an exceedingly rare dysplasia of the craniocervical junction. To the best of our knowledge, only two cases of atlas-duplication have been reported and these were associated with complete anterior rachischisis and os odontoideum. We aimed to report a case of isolated atlas-duplication of incidental finding and without attributable symptoms which makes it unique. Methods Following a normal coronarography for a suspected myocardial infarction, a 60-year-old-man with no significant medical history developed a transient ischemic attack that justified brain computed-tomography angiography. Results There was no evidence for cerebral ischemic lesion, intracranial occlusion or significant artery disease. Bone analysis revealed eight cervical vertebral segments with an additional vertebral level located between the occiput and the atlas. This vertebra presented all the morphological characteristics of an atlas vertebra except for hypoplasia of the left transverse process. An incomplete anterior rachischisis was associated, and there was no other abnormality of craniocervical junction. The clinical examination revealed no neck pain, no limitation of joint amplitude and no neurological deficit. Apart from preventive treatment of ischemic stroke, no orthopedic or surgical treatment was undertaken. After 1.5 years of radiological monitoring, the patient remains symptom-free. Conclusions Atlas-duplication is an exceedingly rare dysplasia of the craniocervical junction that may be found isolated and incidentally. If this variation does not necessarily warrant specific treatment, brain CT angiography is recommended to detect anatomical variations of the vertebral arteries.
... Lastly, parts of the second and third cervical somites combine to create the body of the C2 vertebra. The intervertebral disc common in the rest of the vertebral column is embryologically converted into the upper and lower dental synchondroses, which connect the apical dens to the basal dens and the basal dens to the axis body, respectively [1,18,[28][29][30]. The odontoid process should fuse with the C2 body by the time a child is a toddler [20,23]. ...
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Purpose Potential asymmetries of the C2 posterior elements pose a problem for the spine surgeon seeking to make the best choice for spinal stabilization while reducing morbidity. Methods A digital caliper was used to measure the pars interarticularis height and length on left and right sides of 25 adult C2 vertebrae. The pars interarticularis was defined as the bone between the posterior most aspect of the superior articular process and the anterior most aspect of the inferior articular process of C2. Also, the C2 vertebrae from 49 patients were scanned by CT. Parasagittal images were reviewed and using the same definitions as were used for the skeletal specimens, the length and the height of the C2 pars interarticularis from both the left and right sides were measured using CT. The image slices were acquired at 3 mm intervals. The pars interarticularis height was determined on sagittal CT reconstruction, while the pars interarticularis length was calculated on the basis of the axial images. Results The lengths and the heights of the left and right pars interarticularis were compared using CTs of patients and skeletal specimens. No significant differences were found in the length and height measurements of the CT images on both sides. However, in the skeletal specimens, the left and right pars interarticularis did not differ significantly in length but differed significantly in height (p = 0.003). The mean height of the left pars interarticularis was approximately two times larger than the right in the skeletal specimens. Absolute differences were calculated between the side with the greater length and height and the side with the lesser length and height irrespective of their left–right orientations. For CT measurements, most differences in length and height between the greater pars interarticularis and lesser pars interarticularis occurred between 0 and 1 mm with each successive disparity interval yielding lower numbers. Skeletal measurements revealed a similar length disparity distribution to the CT measurements. However, height measurements in the skeletal specimens varied widely. Eight pars interarticularis specimens demonstrated a height difference between 0 and 1 mm. No dry bone pars interarticularis specimens demonstrated a height difference between 1 and 2 mm. The pars interarticularis of nine specimens demonstrated a height difference between 2 and 3 mm. Two demonstrated a height difference between 3 and 4 mm. Four demonstrated a height difference between 4 and 5 mm and two demonstrated a height difference greater than 5 mm. The greater pars interarticularis lengths and heights were combined and compared to their lesser counterparts on CT and skeletal measurements. In all measurements of this type, significant differences were found in the pars interarticularis length and height, whether measured through CT or via digital calipers. Conclusion Asymmetry between the left and right C2 pars interarticularis as shown in the present study can alter surgical planning. Therefore, knowledge of this anatomical finding might be useful to spine surgeons.
... KMT2A is essential for embryonic development, hematopoiesis, and neural development. Known targets include the homeobox (HOX) genes, a family of transcription factors essential for normal embryonic development [17,18]. ...
... 12q13, and 2q31, respectively. This highly conserved family belongs to the homeobox class of genes that encode transcription factors required for normal embryonic global development, including brain development [18] and embryology of the bony CVJ [17]. HOX genes function in multiple neuronal classes to shape synaptic specificity during development, suggesting a broader role in circuit assembly. ...
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Wiedemann–Steiner syndrome (WDSTS) is a Mendelian syndromic intellectual disability (ID) condition associated with hypertrichosis cubiti, short stature, and characteristic facies caused by pathogenic variants in the KMT2A gene. Clinical features can be inconclusive in mild and unusual WDSTS presentations with variable ID (mild to severe), facies (typical or not) and other associated malformations (bone, cerebral, renal, cardiac and ophthalmological anomalies). Interpretation and classification of rare KMT2A variants can be challenging. A genome-wide DNA methylation episignature for KMT2A-related syndrome could allow functional classification of variants and provide insights into the pathophysiology of WDSTS. Therefore, we assessed genome-wide DNA methylation profiles in a cohort of 60 patients with clinical diagnosis for WDSTS or Kabuki and identified a unique highly sensitive and specific DNA methylation episignature as a molecular biomarker of WDSTS. WDSTS episignature enabled classification of variants of uncertain significance in the KMT2A gene as well as confirmation of diagnosis in patients with clinical presentation of WDSTS without known genetic variants. The changes in the methylation profile resulting from KMT2A mutations involve global reduction in methylation in various genes, including homeobox gene promoters. These findings provide novel insights into the molecular etiology of WDSTS and explain the broad phenotypic spectrum of the disease.
... As with this case, a dislocated and persistent ossiculum terminale has been documented as an accompanying bony aberration. [10,11] Atlantoaxial instability co-exists as the central pivot is hypoplastic when bifid; this is further exaggerated by dislocated ossiculum terminale. Occasionally dynamic instability with flexion-extension may occur in hypermobile "hemi-os." ...
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Recurrent Postreior circulation stroke due to CV junction anomaly
... As with this case, a dislocated and persistent ossiculum terminale has been documented as an accompanying bony aberration. [10,11] Atlantoaxial instability co-exists as the central pivot is hypoplastic when bifid; this is further exaggerated by dislocated ossiculum terminale. Occasionally dynamic instability with flexion-extension may occur in hypermobile "hemi-os." ...
... Here as well, we saw no differences between the groups, suggesting that subtle morphologic changes in the AS group were not present. While common in other arthopathies, such as rheumatoid arthritis, basilar invagination is rare in AS as pannus formation and degenerative destruction of the craniocervical junction has only been documented in late stage disease [20,21,29]. ...
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Introduction: Cervical ligamentous injuries in patients with ankylosing spondylitis (AS) may be difficult to detect, even with the utilization of computed tomography (CT) scans. The purpose of this study was to investigate the influence AS has on various radiologic parameters used to detect traumatic and degenerative pathologies of the cervical spine. Methods: A matched, case-control retrospective analysis of patients with AS and controls without AS admitted at two level-1 trauma centers was performed. All patients were admitted via shock room and received a polytrauma CT. Study patients were included if they had no injury to the cervical spine. Twenty-four CT parameters of atlanto-occipital dislocation/ instability, traumatic and degenerative spondylolisthesis, basilar invagination, and prevertebral soft-tissue swelling were assessed. Study patients were matched by age and sex. Results: A total of 78 patients were included (AS group, n=39; control group, n=39). The evaluated cervical radiologic parameters were largely within normal limits and showed no significant clinical or morphologic differences between the two groups. Conclusion: In this analysis, CT measurements pertaining to various cervical pathologies were not different between patients with and without ankylosing spondylitis. Parameters to assess for atlanto-occipital dislocation/ instability, spondylolisthesis, or basilar invagination may reliably be used in patients with AS.