Congenital Unilateral Atlanto-Occipital Rotatory Subluxation: Rare Cause of C1 Neuralgia.
Bapat Mihir R,Gujral Amandeep,Patel Bharat K
Spine
STUDY DESIGN:Case report. OBJECTIVE:We report a rare case of congenital unilateral rotatory atlanto-occipital subluxation that presented with left C1 neuralgia. SUMMARY OF BACKGROUND DATA:Secondary occipital neuralgia is commonly attributed to pathologies of the atlanto-axial joint and C2/C3 nerve involvement. Our case depicts a model of slow creeping atlanto-occipital subluxation due to a rare left C1 superior articular facet dysplasia with C1 foraminal stenosis presenting as C1 neuralgia. We discuss the eitology and patho-anatomy of this rare undescribed presentation. METHODS:A 42-year-old gentleman presented with deteriorating and intractable left occipital headache of 6 months duration. The neck disability index (NDI) was 64%. Cervical MR/computed tomography scan showed a unilateral C1 facet dysmorphism with a left sided C1 foramen bony compression. There was no central canal stenosis. RESULTS:Posterior left C1 arch excision and decompression of C1 foramina with occipital-cervical fusion relieved C1 neuralgia. CONCLUSION:Our case depicts a model of slow creeping deformation due to left C1 superior articular facet dysplasia. An abnormal facet slope allowed the occipital condyle to migrate posteriorly and medially leading to crowding of the left C1 foramen. Although the etiology was congenital, the neck spasm was delayed till fourth decade. A secondary C1 foramen stenosis led to C1 occipital neuralgia that presented as an intractable headache. LEVEL OF EVIDENCE:5.
10.1097/BRS.0000000000002724
Agenesis of the posterior arch of the atlas and complex alterations of the craniovertebral junction: A case report.
Madeddu Roberto,Cecchini Andrea,Mazzarello Vittorio,Sotgiu Maria Alessandra,Farace Cristiano,Bandiera Pasquale
Radiology case reports
The craniovertebral junction is a unique part of the somite-derived axial skeleton. The absence or hypoplasia of the posterior arch of C1 is frequently associated with compensatory hypertrophy of the anterior arch of C1 and of the spinous process of C2. Here, we report a patient with agenesis of the posterior arch of C1 without neurologic deficits. Our patient presented with complex alterations of the craniovertebral junction that involved interactions between the condyles, clivus, atlas, and epistropheus. To our knowledge, dislocation of the odontoid process above the Chamberlain line, including cranial migration of the anterior arch of C1, has not been reported in the literature.
10.1016/j.radcr.2019.05.033
Congenital anterior midline cleft of the atlas and posterior atlanto-occipital fusion associated with symptomatic anterior atlantoaxial subluxation.
He Qingyi,Xu Jianzhong
European journal of orthopaedic surgery & traumatology : orthopedie traumatologie
BACKGROUND:Congenital partial anterior arch defect of the atlas is extremely rare. It could be found as an incidental radiological finding or patients can present with neurological deficit after head or neck trauma. OBJECTIVE:To describe an extremely rare presentation of anterior midline cleft at the atlas and congenital posterior atlanto-occipital fusion with symptomatic anterior atlantoaxial subluxation. This report includes a feasible hypothesis for the development of this anomaly on the basis of previous hypotheses and surgical findings. METHODS:A 46-year-old female presented with a 6-day history of right limbs numb and left upper and lower extremities paraparesis (Frankel D). Radiographs of the cervical spine showed anterior atlantoaxial subluxation with congenital posterior atlanto-occipital fusion. Computed tomography subsequently revealed partial midline absence of the anterior arch of the atlas and the odontoid tip ahead of the anterior arch of the atlas. Magnetic resonance imaging showed that the cervical dura was compressed by the remnant of anterior arch of the atlas. The patient underwent Gardner-Wells tong traction and surgery of occipitocervical fusion with autogenous iliac bone graft because she had definite neurological symptom and congenital posterior atlanto-occipital fusion. RESULTS:Atlantoaxial reduction was confirmed with fluoroscopic X-ray evaluation by bed, her neurological deficit was resolved from Frankel D to E, and numb of right limbs completely disappeared 6 days postoperation. No instability has been observed during 2-year follow-up. CONCLUSION:We describe the association between compressive myelopathy and congenital defect of the anterior arch of the atlas with symptomatic anterior atlantoaxial subluxation. Both computed tomography and magnetic resonance image were required to demonstrate the bony configuration and cord compression. And Gardner-Wells tong traction and surgery of occipitocervical fusion with autogenous iliac bone graft were effective as a treatment for this compressive myelopathy caused by the remnant of anterior arch of the atlas.
10.1007/s00590-012-1011-2
Hypertrophic posterior arch of atlas causing cervical myelopathy.
Kasliwal Manish Kumar,Traynelis Vincent Charles
Asian spine journal
Cervical stenosis, especially of the upper cervical spine, is quite rare which can be developmental or acquired. Clefts or aplasias of anterior and posterior arches of atlas, ossification of the transverse atlantal ligament, hypertrophy of the dens and os odontoideum are rare conditions causing cervical myelopathy reported either singly or in combination. Hypertrophy of the posterior arch of atlas in the absence of any ring hypoplasia as a cause of cervical myelopathy has not been reported earlier. The authors report a case of cervical myelopathy in a 26-year-old female due to hypertrophied posterior arch of atlas which was preoperatively diagnosed as a bony tumor. Being aware of such an entity may avoid diagnostic surprises and facilitate patient prognostication and management.
10.4184/asj.2012.6.4.284
Horizontal fracture of the anterior arch of the atlas.
Stewart G C,Gehweiler J A,Laib R H,Martinez S
Radiology
Horizontal fracture of the anterior arch of the atlas can be easily overlooked on lateral radiographs. The fracture is not associated with neurological deficit but may be the cause of severe pain. A review of the literature reveals only 3 previously reported cases. Seven new cases, including 2 without other cervical spine fractures, indicate a much higher incidence than was previously thought. Hypotheses about the mechanism of injury are discussed.
10.1148/122.2.349
Hypertrophy of the anterior arch of the atlas associated with congenital nonunion of the posterior arch: a retrospective case-control study.
Jin Michael,Asadoorian Mariet,Hiller Lucas P,Hughes Tudor H
The spine journal : official journal of the North American Spine Society
BACKGROUND CONTEXT:Nonunion of the posterior arch of the atlas is an uncommon but normal developmental variant. It is usually asymptomatic in the patient but may be associated with greater incidence of fracture because of increased stress on the anterior arch. PURPOSE:We sought to determine whether anterior arch hypertrophy is present in cases of congenital nonunion of the posterior arch of the atlas. STUDY DESIGN/SETTING:A retrospective analysis of 1 year (February 2005-January 2006) of computed tomography cervical spine studies requested by the University of California San Diego Medical Center Trauma Department was undertaken. PATIENT SAMPLE:All patients matching the search criteria (see Study design) were included. OUTCOME MEASURES:Area density product, defined as the midline cross-sectional area of the anterior arch on sagittal reformat multiplied by the average areal radiodensity in Hounsfield units (HU) as measured by two raters, was calculated for cases and controls. METHODS:Cases of posterior arch nonunion were identified and matched to controls. The significance of differences in area density product between cases and controls were established by the Student t test. Interrater correlation was calculated. RESULTS:Posterior arch nonunion was identified in 26 individuals (3.1% of 839 studies reviewed). Compared with age- and sex-matched controls, a 21% increase in area density product of the midline anterior arch was observed in posterior arch nonunion cases (773 HU-cm2 in cases vs. 637 HU-cm2 in controls; p<.001). This increase was attributable to a 21% increase in cross-sectional area (1.05 cm2 in cases vs. 0.87 cm2 in controls; p<.002). In contrast, there was no significant difference with regard to increased average radiodensity. CONCLUSIONS:It has long been subjectively recognized but not objectively quantified, until the present study, that the anterior arch of the atlas is hypertrophied in cases of posterior arch nonunion. Anterior arch hypertrophy may represent an adaptive response to chronically elevated mechanical stress and loss of hoop strength in cases of posterior nonunion.
10.1016/j.spinee.2013.07.482
Posterior arch reconstruction in cervical surgery to restore the global biomechanics of the Atlas: a technical note.
British journal of neurosurgery
The posterior arch of the atlas is usually not considered one of the main stabilizers of the cranio-cervical junction, allowing surgeons to its removal when needed with a relative certainty to preserve the stability of the atlo-axial segment. However, these considerations do not reflect the importance to examine the integrity of the posterior arch in the whole biomechanics of the atlas. Authors like Gebauer and Panjabi revealed, respectively in experimental and clinical conditions, how the atlas responds to an axial loading force, proving that the whole atlas is involved into horizontal conversion of axial forces and providing evidence supporting the preservation of the posterior arch. Other authors evaluated the risk for anterior arch fracture following C1 laminectomy. In this technical note three different techniques of posterior atlas arch reconstruction after surgical iatrogenic disruption are presented, considering both neoplastic and degenerative disease.
10.1080/02688697.2021.1881042
Traumatic injury to the unfused anterior arch of C1 in the setting of bipartite atlas.
Boron Agnieszka,Epelman Monica,Shah Chetan,Scherer Andrea,Chandra Tushar
Pediatric radiology
We present a case of a pediatric patient with congenital unfused anterior and posterior arches of the atlas (C1), also known as bipartite atlas, who sustained a traumatic injury during gymnastics. A computed tomography (CT) scan of the cervical spine raised concern for abnormal separation of the midline cleft of the anterior arch of C1. Subsequent magnetic resonance imaging (MRI) showed focal, edema-like signal in the midline cleft of C1. She was advised by neurosurgery to remain in a hard cervical collar for 6 weeks. She recovered after conservative treatment and returned to gymnastics. This case shows that a congenital unfused anterior arch of the atlas identified on CT after cervical trauma should not always be interpreted as an incidental finding. If a superimposed injury is suspected, MRI helps evaluate for traumatic injury, particularly if it is associated with upper cervical pain and tenderness or pain with neck movements. An additional case reiterates our findings.
10.1007/s00247-021-04990-4
Incidence and variants of posterior arch defects of the atlas vertebra.
Guenkel Sebastian,Schlaepfer Sladjana,Gordic Sonja,Wanner Guido A,Simmen Hans-Peter,Werner Clément M L
Radiology research and practice
In order to describe the incidence and existing variants of congenital anomalies of the atlas vertebrae in a Caucasian population, we examined 1069 CT scans of the upper cervical spine. We found 41 cases with altered atlas vertebrae, representing 3.8% of all analyzed patients. With 83% of all found anomalies, the predominant type is characterized by a small dorsal cleft (3.2% of all patients). Rare varieties feature unilateral or bilateral dorsal arch defects, combined anterior and posterior clefts (0.2% of all patients) or total erratic atlas vertebra malformation (0.1% of all patients). Atlas arch defects are found nearly 4% at the time. Most anomalies affect the posterior arch, whereas the anterior arch or both are rarely affected. Totally irregular C1 vertebrae are extremely infrequent.
10.1155/2013/957280
Incidence of Congenital Posterior Arch Defects of the Atlas in Chinese Population.
World neurosurgery
OBJECTIVE:To study the incidence of congenital posterior arch defects of the atlas and in combination with other congenital variations in the Chinese population. METHODS:We retrospectively reviewed 1405 images of cervical 3-dimensional computed tomography (3D CT) and 1284 images of head and cervical 3-dimensional computed tomography angiography (3D CTA), including images of 1539 male and 1150 female individuals. These images of cervical 3D CT and head and cervical 3D CTA were obtained in the Department of Radiology of 2 hospitals, Second and Third People's Hospital of Jingzhou, China, from January 2020 to October 2023. Congenital posterior arch defects of the atlas were classified according to the criteria of Currarino and colleagues. 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. RESULTS:A total of 2689 patients were included in this study. The overall prevalence of congenital posterior arch defects of the atlas was 0.74% (20 of 2689). There was no statistically significant difference in incidence between male (0.78%, 12 of 1539) and female patients (0.70%, 8 of 1150) (P > 0.05). Among all posterior defects, type A and B defects were found in 0.6% (16 of 2689) and 0.15% (4 of 2689) cases, respectively. There were no type C, D, and E defects and no anterior arch defects. However, in 20 cases of congenital posterior arch defects of atlas, 40% (8 of 20) combined with other congenital variations including occipitalization of atlas in 4 type A cases, bilateral complete ponticulus posticus variation of atlas vertebral groove in 1 type A case, C2-C3 fusion in 1 type A case, coexistence of unilateral complete ponticulus posticus variation of the vertebral artery groove of the atlas and unilateral unclosed transverse foramen in 1 type B case, and coexistence of unilateral unclosed transverse foramen in 1 type A case. CONCLUSIONS:The incidence of congenital posterior arch defects of the atlas was low in a Chinese population. There was no difference between male and female individuals. Types A and B were the 2 major defects in this Chinese population, and the prevalence of type A and B combined with other congenital cervical variations were higher than those of types C, D, and E.
10.1016/j.wneu.2024.10.026
Radiologic evaluation of congenital anomalies of anterior and posterior arch of atlas in Omani subjects.
Hinai Ghaliya Al,Shandoodi Mai Al,Sirasanagandla Srinivasa Rao,Sarhani Salwa Al,Dhuhli Humoud Al,Jaju Sanjay,Mushaiqri Mohamed Al
Anatomy & cell biology
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.
10.5115/acb.21.101