Congenital Absence of the Posterior Element of C1, C2, and C3 Along with Bilateral Absence of C4 Pedicles: Case Report and Review of the Literature

Sharifi, Guive; Lotfinia, Mahmoud; Rahmanzade, Ramin; Lotfinia, Ahmad Ali; Rahmanzadeh, Reza; Omidbeigi, Mahmoud; Meybodi, Emami

doi:10.1016/j.wneu.2017.12.070

“…Posterior element anomalies may be caused by impairment of fusion between the primary ossification centres lying at the base of the articular process [25]. In humans, headache, neck pain and paresis have been reported symptoms [26]. In most cases, anomalies are found incidentally in asymptomatic patients, when the patient undergoes a radiologic assessment for neck pain, radiculopathy, neck mass or following trauma [26].…”

Section: Discussionmentioning

confidence: 99%

“…In humans, headache, neck pain and paresis have been reported symptoms [26]. In most cases, anomalies are found incidentally in asymptomatic patients, when the patient undergoes a radiologic assessment for neck pain, radiculopathy, neck mass or following trauma [26]. Common anomalies of the axis include total or partial absence of the odontoid process, non-fusion of the odontoid process, segmentation failure of the second and third cervical vertebrae [27].…”

Section: Discussionmentioning

confidence: 99%

“…The relatively mild protrusion may have exacerbated an already compromised spinal cord from instability, causing a more acute recent deterioration. Give the current evidence in the human literature [25, 26, 28] and the two cases reported, surgery should be the treatment of choice in patients with radiological evidence of instability, intractable long-standing neck pain and neurologic deficits. The surgical management of these cases through ventral stabilisation resulted in a successful long-term clinical outcome for both patients, despite the initial complications associated with implant failure in case 7.…”

Section: Discussionmentioning

confidence: 99%

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Cervical vertebral malformations in 9 dogs: radiological findings, treatment options and outcomes

Fernandes

¹

,

Fitzpatrick

²

,

Rusbridge

³

et al. 2019

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Background Disregarding atlantoaxial instability in toy breed dogs associated with dens malformation and cervical spondylomyelopathy; cervical vertebral malformations are rare and poorly characterised in veterinary medicine and consequently treatment strategies and clinical outcome are sparsely documented. Results Electronic clinical records at our veterinary referral hospital between April 2009 and November 2018 were searched for patients presented with cervical myelopathy secondary to an underlying suspected vertebral malformation/instability. Nine dogs met the inclusion criteria. Two dogs were diagnosed with atlantoaxial pseudoarthrosis, two dogs with a syndrome similar to Klippel-Feil in humans, two dogs with congenital cervical fusion, two dogs with congenital C2-C3 canal stenosis and deficiencies of the dorsal arch of the atlas and laminae of the axis and one with axial rotatory displacement. Tetraparesis, proprioceptive deficits, cervical hyperesthesia and cervical scoliosis were the most common clinical signs. The axis was the most commonly affected vertebrae (8/9 patients). Patients diagnosed with Klippel-Feil-like Syndrome were the younger (average of 262.5 days) and patients diagnosed with fused vertebrae the oldest (average of 2896 days) in our studied population (average of 1580.8 days). Conclusion Cervical vertebral malformations are rare, or alternatively, being underdiagnosed in veterinary medicine. Patients diagnosed with Klippel-Feil-like Syndrome had a successful medium and long-term outcome with conservative management. Surgical treatment was often indicated for the other conditions presented in this study due to spinal instability and/or myelopathy. Stabilisations via ventral approaches were revealed to be safe. Multicentre and prospective studies are necessary in veterinary medicine to better characterise clinical outcomes in cervical vertebral malformations.

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“…Posterior surgery is prone to damage of the vertebral artery and nerves [25], resulting in severe consequences such as massive haemorrhage of the vertebral artery, cerebral infarction and hemiplegia caused by vertebral artery embolism, and dyspnoea resulting from central nervous system damage; in severe cases, the life of the patient may be in danger [26,27]. Some cases involve difficulties and risks when using the posterior approach, such as the abnormal development and pathway of the vertebral artery [28][29][30] and congenital or iatrogenic absence of the bony structure of the atlantoaxial vertebra pedicle [31,32], and the atlantoaxial complex can be more safely fused through the anterior approach.…”

Section: Discussionmentioning

confidence: 99%

Design a novel integrated screw for minimally invasive atlantoaxial anterior transarticular screw fixation: a finite element analysis

Zhang

¹

,

Li

²

,

Li

³

et al. 2020

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Purpose: To design a new type of screw for minimally invasive atlantoaxial anterior transarticular screw (AATS) fixation with a diameter that is significantly thicker than that of traditional screws, threaded structures at both ends, and a porous metal structure in the middle. The use of a porous metal structure can effectively promote bone fusion and compensate for the disadvantages of traditional AATSs in terms of insufficient fixation strength and difficulty of bone fusion. The biomechanical stability of this screw was verified through finite element analysis. This instrument may provide a new surgical option for the treatment of atlantoaxial disorders. Methods: According to the surgical procedure, the new type of AATS was placed in a three-dimensional atlantoaxial model to determine the setting of relevant parameters such as the diameter, length, and thread to porous metal ratio of the structure. According to the results of measurement, the feasibility and safety of the new AATS were verified, and a representative finite element model of the upper cervical vertebrae was chosen to establish, and the validity of the model was verified. Then, finite element-based biomechanical analysis was performed using three models, i.e., atlantoaxial posterior pedicle screw fixation, traditional atlantoaxial AATS fixation, and atlantoaxial AATS fixation with the new type of screw, and the biomechanical effectiveness of the novel AATS was verified.

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“…resulting from central nervous system damage; in severe cases, the life of the patient may be in danger [24,25]. Some cases involve difficulties and risks when using the posterior approach, such as the abnormal development and pathway of the vertebral artery [26][27][28] and congenital or iatrogenic absence of the bony structure of the atlantoaxial vertebra pedicle [29,30], and the atlantoaxial complex can be more safely fused through the anterior approach.…”

Section: Discussionmentioning

confidence: 99%

Design a novel integrated screw for minimally invasive atlantoaxial anterior transarticular screw fixation: a finite element analysis

Zhang

¹

,

Li

²

,

Li

³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

Purpose: To design a new type of screw for minimally invasive atlantoaxial anterior transarticular screw (AATS) fixation with a diameter that is significantly thicker than that of traditional screws, threaded structures at both ends, and a porous metal structure in the middle. The use of a porous metal structure can effectively promote bone fusion and compensate for the disadvantages of traditional AATSs in terms of insufficient fixation strength and difficulty of bone fusion. The biomechanical stability of this screw was verified through finite element analysis. This instrument may provide a new surgical option for the treatment of atlantoaxial disorders.Methods: According to the surgical procedure, the new type of AATS was placed in a three-dimensional atlantoaxial model to determine the setting of relevant parameters such as the diameter, length, and thread to porous metal ratio of the structure. According to the results of measurement,the feasibility and safety of the new AATS was verified, and a representative finite element model of the upper cervical vertebrae was chosen to establish, and the validity of the model was verified. Then, finite element-based biomechanical analysis was performed using three models, i.e., atlantoaxial posterior pedicle screw fixation, traditional atlantoaxial AATS fixation, and atlantoaxial AATS fixation with the new type of screw, and the biomechanical effectiveness of the novel AATS was verified.Results: By measuring the atlantoaxial parameters, the atlantoaxial CT data of the representative 30-year-old normal adult male were selected to create a personalized 3D printing AATS screw. In this case，the design parameters of the new screw were determined as follows: diameter, 6mm; length of the head thread structure, 10 mm; length of the middle porous metal structure, 8 mm (a middle porous structure containing an annular cylinder );length of the tail thread structure, 8 mm; and total length,26 mm. Apply the same load conditions to the atlantoaxial complex along different directions in the established finite element models of the three types of atlantoaxial fusion modes, the immediate stability of the new AATS is similar with Atlantoaxial posterior pedicle screw fixation.They are both superior to traditional atlantoaxial anterior screw fixation.The maximum local stress on the screw head in the atlantoaxial anterior surgery were less than those of traditional atlantoaxial anterior surgery.Conclusions: By measuring relevant atlantoaxial data, we found that screws with a larger diameter can be used in AATS surgery, and the new AATS can make full use of the atlantoaxial lateral mass space and increase the stability of fixation. The finite element analysis and verification revealed that the biomechanical stability of the new AATS was superior to the AATS used in traditional atlantoaxial AATS fixation. The porous metal structure of the new AATS may promote fusion between atlantoaxial joints and allow more effective bone fusion in the minimally invasive anterior approach surgery.

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Congenital Absence of the Posterior Element of C1, C2, and C3 Along with Bilateral Absence of C4 Pedicles: Case Report and Review of the Literature

Cited by 10 publications

References 24 publications

Cervical vertebral malformations in 9 dogs: radiological findings, treatment options and outcomes

Cervical vertebral malformations in 9 dogs: radiological findings, treatment options and outcomes

Design a novel integrated screw for minimally invasive atlantoaxial anterior transarticular screw fixation: a finite element analysis

Design a novel integrated screw for minimally invasive atlantoaxial anterior transarticular screw fixation: a finite element analysis

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