Posterior Arch Defects Research Articles

Incidence of Congenital Posterior Arch Defects of the Atlas in Chinese Population

To study the incidence of congenital posterior arch defects of the atlas and in combination with other congenital variations in the Chinese population. 1405 images of cervical three-dimensional computed tomography (3D CT) and 1284 images of head and cervical three-dimensional computed tomography angiography (3D CTA) were retrospectively reviewed, including images of 1539 males and 1150 females. These images of cervical 3D CT and head and cervical 3D CTA were obtained in the Department of Radiology of two hospitals, Second and Third People's Hospital of Jingzhou, China, from January 2020 to October 2023. And congenital posterior arch defects of the atlas were classified according to the criteria of Currarino et al. Congenital posterior arch defects of the atlas combined with other congenital variations including occipitalization of the atlas, the ponticulus posticus variation of the vertebral artery groove of the atlas, cervical fusion, and the transversal foramen of the atlas variant were also observed. A total of 2689 subjects were included in this study. The overall prevalence of congenital posterior arch defects of the atlas was 0.74% (20/2689). There was no statistically significant difference in incidence between males (0.78%,12/1539) and females (0.70%,8/1150) (P >0.05). Among all posterior defects, type A and B defects were found in 0.6% (16/2689) and 0.15% (4/2689) cases, respectively. There were no type C, D, and E defects and no anterior arch defects. But in 20 cases of congenital posterior arch defects of atlas, 40%(8/20) combined with other congenital variations including occipitalization of atlas in 4 type A cases, bilateral complete ponticus posticus variation of atlas vertebral groove in one type A case, C2-3 fusion in one type A case, coexistence of unilateral complete ponticulus posticus variation of the vertebral artery groove of the atlas and unilateral unclosed transverse foramen in one type B case, and coexistence of unilateral unclosed transverse foramen in one type A case. The incidence of congenital posterior arch defects of the atlas was low in Chinese population. There was no difference between males and females. Type A and B were the two major defects in Chinese population, and the prevalence of type A and B combined with other congenital cervical variations were higher than those of type C, D, and E.

Radiological Study of Atlas Arch Defects with Meta-Analysis and a Proposed New Classification.

This study consists of a retrospective cohort study, a systematic review, and a meta-analysis which were separately conducted. This study aimed to investigate the prevalence of atlas arch defects, generate an evidence-based synthesis, and propose a common classification system for the anterior and combined atlas arch defects. Atlas arch defects are well-corticated gaps in the anterior or posterior arch of the atlas. When both arches are involved, it is known as a combined arch defect. Awareness of these defects is essential for avoiding complications during surgical procedures on the upper spine. The prevalence of arch defects was investigated in an open-access OPC-Radiomics (Radiomic Biomarkers in Oropharyngeal Carcinoma) dataset comprising 606 head and neck computed tomography scans from oropharyngeal cancer patients. A systematic review and meta-analysis were performed to generate prevalence estimates of atlas arch defects and propose a classification system for the anterior and combined atlas arch defects. The posterior arch defect was found in 20 patients (3.3%) out of the 606 patients investigated. The anterior arch defect was not observed in any patient, while a combined arch defect was observed in one patient (0.2%). A meta-analysis of 13,539 participants from 14 studies, including the present study, yielded a pooled-posterior arch defect prevalence of 2.07% (95% confidence interval [CI], 1.22%-2.92%). The prevalences of anterior and combined arch defects were 0.00% (95% CI, 0.00%-0.10%) and 0.14% (95% CI, 0.04%-0.25%), respectively. The anterior and combined arch defects were classified into five subtypes based on their morphology and frequency. The present study showed that atlas arch defects were present in approximately 2% of the general population. For future studies, larger sample sizes should be used for studying arch defects to avoid the small-study effect and to predict the prevalence accurately.

Increased medial pedicle angulation of the lumbar spine as a function of the posterior osseous defect in patients with myelomeningocele.

Bony anatomy in patients with immature spines has been previously characterized. Alterations in lumbosacral morphology in patients with myelodysplasia, demonstrating increasing medial pedicle angulation (MPA) from L1-S1, have been examined; however, MPA related to size of the defect in myelomeningocele patients has not been defined. We aimed to establish that magnitude of posterior vertebral arch defects determines the extent of MPA in the lumbar spine, with larger posterior defects associated with increased MPA. This retrospective case-control study compared lumbar morphometric measurements of patients with and without myelomeningocele. Eighteen patients with myelomeningocele underwent computed tomography with three-dimensional reconstruction; there was no concurrent pathology. Advanced imaging software was utilized to manipulate the axial, sagittal, and coronal axes at each lumbar level, and obtain accurate measurements of pedicle width, height, length, MPA, and posterior laminar defect. In lumbar vertebrae with a posterior arch defect (PAD), increased magnitude was associated with a concurrent increase in MPA between 16.2° (43.4%) and 28.1° (299.4%) depending on lumbar level. At levels without a PAD, increases in MPA were between 0.8° (4.3%) and 5.7° (60.6%) depending on lumbar level. Although the actual degree of medial angulation increases from cephalad to caudal levels, the percentage of deviation from normal is higher at the more cephalad levels compared with controls. In patients with myelomeningocele, larger posterior vertebral arch defects were associated with increased MPA in the lumbar spine. Lumbar levels without a PAD also demonstrated increases in MPA compared with normal values.

Radiologic evaluation of congenital anomalies of anterior and posterior arch of atlas in Omani subjects

The atlas (C1) is known to present congenital anomalies in its anterior and posterior arches. The reported incidence of C1 anomalies is varied among the ethnic groups. We sought to determine the prevalence and various existing variations of C1 arch congenital anomalies in Omani subjects. This study was carried out by reviewing the cervical spine computed tomography scans of all the patients who had been referred to the Radiology Department, Sultan Qaboos University Hospital. Descriptive statistics and chi-square test were employed to analyse the data. A total of 663 subjects aged ≥18 years were included in the present study. Overall prevalence of C1 arch anomalies was 4.37% with 4.07% of isolated posterior arch anomalies, 0.3% of combined anterior and posterior arch anomalies. Among isolated posterior arch anomalies, type A and type B posterior arch defects were found in 3.77% and 0.3% of cases, respectively. Atlanto-occipital assimilation was noted in one case of total study subjects. The prevalence rate of C1 arch anomalies is relatively high in Omani subjects. The baseline data of C1 arch anomalies reported in the present study has a great impact on clinical practice, due to the fact that studying and evaluating the types of congenital anomalies helps in their accurate diagnosis and early intervention.

Airway Management of Type-III Arnold Chiari Malformation: An Anaesthetic Challenge.

Arnold Chiari malformation (ACM) is defined as protrusion of the meninges and brain components into a congenital defect in the cranium or in the vertebral column. It was originally described by Austrian pathologist Hans Chiari. Among the four types, type-III ACM is the rarest and may associate with encephalocele. We report a case of type-III ACM associated with large occipitomeningoencephalocele with herniation of dysmorphic cerebellum, vermis, kinking/herniation of medulla with cerebrospinal fluid, tethering of spinal cord with posterior arch defect of C1-C3 vertebrae. The anaesthetic challenge for such patients lies in the proper preoperative work up; proper positioning of the patient during intubation; safe anaesthetic induction; intraoperative management of intracranial pressure, normothermia, and fluid and blood loss; and postoperative planning of extubation to prevent aspiration are the prerequisites to overcome the dificult airway management and anaesthetic challenge in the management of type III ACM.

Dermal Sinus Track with Intraspinal Dumbbell Mature Cystic Teratoma in an Infant Presenting as Recurrent Meningitis: A Case Report

Cystic mature teratomas presenting in the spine are rare, comprising less than 0.1% of all spinal tumors. They arise from all three germ cell layers and usually accompany other congenital abnormalities. Spinal teratomas are more common in children as compared to adults and are usually associated with spinal dysraphism. Dermal Sinus is a closed type of Spinal dysraphsim, lined with epithelium and are mostly associated with Dermoid, Epidermoid and Posterior arch defect [1]. We present a case of an infant with recurrent meningitis. His examination was remarkable for a lumbar dimple. Imaging revealed a dermal sinus track continuous with a dumbbell appearance of extradural and intradural nodules, while the histopathology confirmed mature cystic Teratoma.

Incidental findings of posterior arch defects of the atlas in orthodontic patients: A case series

Congenital defects of the posterior arch of atlas are uncommon anomalies that may go unnoticed. Radiographs and cone-beam computed tomography scans made for orthodontic purposes often show the atlas; therefore, these rare defects might first be noted as incidental findings on orthodontic records. A series of 7 cases of posterior arch defects of atlas (C1) that were detected during routine radiographic examination are presented here. The distribution of the defects was as follows: type A, 2; type B, 1; type C, none; type D, 1; and type E, 3. As the potential complications associated with these defects may be quite concerning, a thorough analysis of the radiographs for these defects is imperative.

Prevalence of anatomic variations of the atlas vertebra.

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. To analyze the prevalence of the AF, RTF, UTF, and PAAD. Ex-vivo anatomical study. 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). 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. Not applicable. 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). 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.

Epidermoid tumor of the fourth ventricle with accompanying congenital posterior arch defect of the atlas

Epidermoid tumors are rarely encountered within the fourth ventricle. There are slightly more than 100 cases reported in the literature. Congenital posterior arch defects of the atlas are also rare with less than 50 cases reported in the literature. The coexistence of these two pathologies in one patient has not been previously reported. We present a 51-year- old-woman with an epidermoid tumor of the fourth ventricle and accompanying posterior arch defect of the atlas.

Posterior Arch Defects of the Atlas - A Report of Two Cases and Literature Review

Posterior Arch Defects of the Atlas - A Report of Two Cases and Literature Review

The prevalence of congenital C1 arch anomalies

To determine the prevalence, radiographic features and reporting rate of, and the association between the congenital anterior and posterior C1 arch anomalies. The computed tomography (CT) images of the cervical spines of all patients over 18years who had CT examinations in our hospital during the study periodwere reviewed to evaluate for congenital anomalies of the anterior and posterior C1 arches. Radiology reports of the corresponding CT examinations were reviewed to determine the reporting rate of these defects. Of 3273 subjects, 185 (5.65%) had congenital atlas anomalies: 169 isolated posterior (5.16%), 15 combined anterior and posterior (bipartite, 0.46%), and one isolated anterior (0.031%) arch defects. Females had a higher prevalence than males (7.46 versus 4.72%, P=0.0013). Eighty-three cases (44.9%) of C1 arch anomalies were not reported. The Currarino type A, B, C and E posterior arch defects accounted for 81.6, 8.1, 1.1, and 0.5% of all arch anomalies while type D was not observed. Fifteen patients (0.46%) had combined anterior and posterior arch anomalies (bipartite atlas) versus only one with an isolated anterior C1 defect, indicating a significant association between the anterior and posterior arch defects (P<0.0001). Although some types of congenital C1 arch anomalies are rare, type A defects are relatively common radiological findings that are unreported approximately 45% of the time. Based on the significant association between the anterior and posterior arch defects, we propose possible mechanisms for the formation of the bipartite atlas.

Diagnostic value of ultrasonography in spinal abnormalities among children with neurogenic bladder.

BackgroundNowadays, magnetic resonance imaging (MRI) is the gold standard for evaluation and diagnosis of spinal cord abnormalities, which are considered among the leading causes of neurogenic bladder; however, MRI is a costly imaging method and is not available at all health centers. Sporadic studies have shown the alignment of MRI with ultrasonography results in diagnosis of spinal abnormalities; although none of these studies has expressed the diagnostic value of ultrasonography.ObjectiveThe aim of this study was to evaluate the diagnostic value of ultrasonography in detection of spinal abnormalities in children with neurogenic bladder.MethodsThis is a cross-sectional study carried out from January 2014 to November 2015 on patients with neurogenic bladder referred to Department of Radiology, Dr. Sheikh Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. All patients underwent sonography of the spinal cord and soft-tissue masses; also, a spinal MRI scan was performed. The existence of spina bifida, sacral agenesis, posterior vertebral arch defects, mass, tethered cord, myelomeningocele, lipoma and fatty infiltration, dural ectasia, hydromyelia and syringomyelia, and diastomatomyelia was recorded during each imaging scan. Chi-square and Fisher’s tests were used for data analysis using SPSS 19.0 software, and the sensitivity and specificity of ultrasonography findings were calculated by MedCale 26 software.ResultsForty patients with neurogenic bladder (22 males/18 females), with an average of 25.73±19.15 months, were enrolled. The most common abnormality was found in patients’ MRI was tethered cord syndrome (70%). There was a significant relationship between ultrasonographic and MRI findings in spina bifida abnormalities (p=0.016), sacral agenesis (p=0.00), tethered cord (p=0.00), myelomeningocele (p=0.00), and lipoma and fatty infiltration (p=0.01). Ultrasonography had a sensitivity of 20.0%–100% and a specificity of 85.7%–100% depending on the detected type of abnormality.ConclusionIt seems that ultrasonography has an acceptable and desirable sensitivity and specificity in the diagnosis of most of the spinal cord abnormalities in children with a neurogenic bladder.

Atlas occipitalisation associated with other anomalies in a 16th century skeleton from Sardinia (Italy).

Archaeological excavations carried out in the plague cemetery of 16th century Alghero (Sardinia) brought to light the skeleton of a male aged 35-45 years, showing anomalies of the atlas. A macroscopic and radiological study has been carried out. The first cervical vertebra is fused with the skull base, resulting in an occipitalisation of the atlas. Absence of the costal element of the left foramen transversarium, resulting in an open anterior foramen transversarium, and posterior arch defect are also observed. The atlanto-occipital junction is a complex structure, susceptible to develop different patterns of congenital defects. These anatomical variations of atlas should be considered in modern clinical practice in order to formulate a correct diagnosis and to conceive an appropriate treatment. Osteoarchaeological cases are important as, beside to ascertain the presence of congenital defects in past populations, allow an in-depth study in dry bones, which can help modern medicine in interpreting anatomical variations. We present an association of congenital anomalies of the atlanto-occipital junction, a condition rarely documented in ancient and modern human skeletal remains.

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

Background ContextTo date, no information about the cortical bone microstructural properties in atlas vertebrae with posterior arch defects has been reported. PurposeTo test if there is an increased cortical bone thickening in atlases with Type A posterior atlas arch defects in an experimental model. Study DesignMicro-computed tomography (CT) study on cadaveric atlas vertebrae. MethodsWe 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. ResultsThe 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. ConclusionsType A congenital atlas arch defects present a cortical bone thickening that may play a protective role against atlas fractures.

A case of midline defect of posterior arch of atlas in a cadaver

AbstractDuring a routine osteology class for undergraduate students in Government Medical College, Kozhikode, Kerala, a median defect of posterior arch was found in the atlas of a cadaver. It was not a fracture as the edges were regular, round and smooth.There was no associated anomalies. These midline defects of posterior arch of atlas are sub divided both morphologically (types A-E) and clinically (sub groups 1-5) depending on the extent of absence of posterior arch and presence or absence of the posterior tubercle.The author presents a rare anomaly of a posterior arch partial aplasia which could be congenital. Since major neurologic deficits can be produced by a minor trauma, it is crucial to recognize this anomaly.

A case of midline defect of posterior arch of atlas in a cadaver

A case of midline defect of posterior arch of atlas in a cadaver

Posterior Arch Defect of the Atlas Associated to Absence of Costal Element of Foramen Transversarium from 16th-Century Sardinia (Italy).

A paleopathological case of posterior arch defect of the atlas associated to the absence of costal element of the foramen transversarium. In living patients as well as in postmortem analysis it should be difficult to distinguish between a congenital and an acquired anomaly. Any anomaly in the anatomy of atlas should be taken into consideration by clinicians, surgeons, radiologists, and anatomists in order to avoid misinterpretations and clinical complications. Posterior arch defect has a current occurrence of approximately 4%. Posterior arch schisis is attributed to the defective or absent development of the cartilaginous preformation of the arch rather than a disturbance of the ossification. The absence of costal element of the foramen transversarium has an incidence of ranging from 2% to 10% and is attributed to a developmental defect or to variations in the course of the vertebral artery. The skeleton of a man aged 20-30 years, brought to light in the plague cemetery of 16th century Alghero (Sardinia), showed anomalies of the atlas, consisting in failure of the midline fusion of the 2 hemiarches with a small gap and an open anterior foramen trasversarium on the left side. A macroscopic, radiological, and stereomicroscopic study was carried out. The study allowed to rule out a traumatic origin of the defects and to diagnose an association of 2 congenital anomalies. Osteoarchaeological cases provides with a valuable opportunity to examine and describe variations in the anatomy of the atlas. N/A.

Posterior arch defect of the atlas in a patient with acute trauma

Posterior arch defect of the atlas in a patient with acute trauma

High prevalence of cervical deformity and instability requires surveillance in Loeys-Dietz syndrome.

Loeys-Dietz syndrome is a connective tissue disorder characterized by vascular, craniofacial, and musculoskeletal malformation. Our goal was to report the manifestations, surgical treatment, and complications in the cervical spine in patients with Loeys-Dietz syndrome. We reviewed the clinical and cervical spine imaging data of eighty patients with Loeys-Dietz syndrome who were seen at our institution from January 2005 through January 2014. Their mean age at presentation was 17.3 years (range, three months to seventy-five years). We tested associations with use of the Fisher exact test (type of TGF-βR [transforming growth factor-beta receptor] mutation and cervical abnormalities) and the Student t test (age at presentation and type of TGF-βR mutation) (significance, p = 0.05). Vertebral anomalies and cervical instability were common; we found no significant association of TGF-βR-type with cervical abnormalities or age at presentation. Twenty-eight patients had atlas defects (anterior and/or posterior arch defects or hypoplasia), fifty-three had axis malformations (elongation, apex-anterior dens angulation, or spondylolysis), and twelve had focal kyphosis. Ten patients had hypoplastic subaxial vertebrae, leading to focal kyphosis (eight) and subaxial instability (nine). Eight patients had atlantoaxial instability. Of the thirteen patients with cervical instability, nine were treated surgically: fusion (eight patients) and halo application (one) (mean age, four years; range, three months to twelve years). Postoperative complications (seven patients) were pseudarthrosis, failure of fixation, junctional kyphosis or instability, and development of occipital-cervical instability. Cervical midline defects (most often C1-C3) are common in Loeys-Dietz syndrome. Patients have a high prevalence of cervical instability, particularly a pattern of instability at C2-C3 associated with C3 vertebral body hypoplasia and C2-C3 focal kyphosis. Patients requiring surgery typically present in early childhood.

Anatomical Variant of Atlas : Arcuate Foramen, Occpitalization of Atlas, and Defect of Posterior Arch of Atlas.

ObjectiveWe sought to examine anatomic variations of the atlas and the clinical significance of these variations.MethodsWe retrospectively reviewed 1029 cervical 3-dimensional (3D) CT images. Cervical 3D CT was performed between November 2011 and August 2014. Arcuate foramina were classified as partial or complete and left and/or right. Occipitalization of the atlas was classified in accordance with criteria specified by Mudaliar et al. Posterior arch defects of the atlas were classified in accordance with criteria specified by Currarino et al.ResultsOne hundred and eight vertebrae (108/1029, 10.5%) showed an arcuate foramen. Bilateral arcuate foramina were present in 41 of these vertebrae and the remaining 67 arcuate foramina were unilateral (right 31, left 36). Right-side arcuate foramina were partial on 18 sides and complete on 54 sides. Left-side arcuate foramina were partial on 24 sides and complete on 53 sides. One case of atlas assimilation was found. Twelve patients (12/1029, 1.17%) had a defect of the atlantal posterior arch. Nine of these patients (9/1029, 0.87%) had a type A posterior arch defect. We also identified one type B, one type D, and one type E defect.ConclusionPreoperative diagnosis of occipitalization of the atlas and arcuate foramina using 3D CT is of paramount importance in avoiding neurovascular injury during surgery. It is important to be aware of posterior arch defects of the atlas because they may be misdiagnosed as a fracture.