Vertebral Artery Anomalies at the Craniovertebral Junction in the US Population

O’Donnell, Courtney; Child, Zachary; Nguyen, Quynh T.; Anderson, Paul A.; Lee, Michael J.

doi:10.1097/brs.0000000000000447

Cited by 47 publications

(29 citation statements)

References 13 publications

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“…The C-1 LMS is a common method for C-1 fixation but it is technically demanding, especially when the lateral mass is obscured by a thick posterior arch, 39 ponticulus posticus, 17 anomalous VA, 17,28,35,37 or a large paravertebral venous plexus. 21 Goel et al reported 2 patients who required an alternative method and only 1-side LMS was completed in 9 cases.…”

Section: Discussionmentioning

confidence: 99%

“…7,21,39 If C1-2 was displaced after injury, the PS may exhibit stronger resistance. It was also shown that the incidence of a VA anomaly between C-1 and C-2 in Asia was more common than in the US, and it directly affected the safety of C-1 LMS placement, 17,28,35,37 so fixation must be planned to minimize the VA injury. The choice was also influenced by our clinical experience.…”

Section: 4mentioning

confidence: 99%

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Unilateral C-1 posterior arch screws and C-2 laminar screws combined with a 1-side C1–2 pedicle screw system as salvage fixation for atlantoaxial instability

Jin

Wang

2016

SPI

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OBJECT Atlantoaxial instability often requires surgery, and the current methods for fixation pose some risk to vascular and neurological tissues. Thus, new effective and safer methods are needed for salvage operations. This study sought to assess unilateral C-1 posterior arch screws (PASs) and C-2 laminar screws (LSs) combined with 1-side C1–2 pedicle screws (PSs) for posterior C1–2 fixation using biomechanical testing with bilateral C1–2 PSs in a cadaveric model. METHODS Six fresh ligamentous human cervical spines were evaluated for their biomechanics. The cadaveric specimens were tested in their intact condition, stabilization after injury, and after injury at 1.5 Nm of pure moment in 6 directions. The 3 groups tested were bilateral C1–2 PSs (Group A); left side C1–2 PSs with an ipsilateral C-1 PAS + C-2 laminar screw (Group B); and left side C1–2 PSs with a contralateral C-1 PAS + C-2 LS (Group C). During the testing, angular motion was measured using a motion capture platform. Data were recorded, and statistical analyses were performed. RESULTS Biomechanical testing showed that there was no significant difference among the stabilities of these fixation systems in flexion-extension and rotation control. In left lateral bending, the bilateral C1–2 PS group decreased flexibility by 71.9% compared with the intact condition, the unilateral C1–2 PS and ipsilateral PAS+LS group decreased flexibility by 77.6%, and the unilateral C1–2 PS and contralateral PAS+LS group by 70.0%. Each method significantly decreased C1–2 movements in right lateral bending compared with the intact condition, and the bilateral C1–2 PS system was more stable than the C1–2 PS and contralateral PAS+LS system (p = 0.036). CONCLUSIONS A unilateral C-1 PAS + C-2 LS combined with 1-side C-1 PSs provided the same acute stability as the PS, and no statistically significant difference in acute stability was found between the 2 screw techniques. These methods may constitute an alternative method for posterior atlantoaxial fixation.

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Section: Discussionmentioning

confidence: 99%

Section: 4mentioning

confidence: 99%

Unilateral C-1 posterior arch screws and C-2 laminar screws combined with a 1-side C1–2 pedicle screw system as salvage fixation for atlantoaxial instability

Jin

Wang

2016

SPI

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“…The CT angiographs were reviewed according to the method provided by O'Donnell et al [4]. Vertebral artery was considered hypoplastic if it was half or less of the diameter of its counterpart.…”

Section: Anatomical Variantsmentioning

confidence: 99%

“…Recently, conflicting data on the incidence of these anomalies have been published. Asian-based studies show high incidence of 10 % of the anomalous course of the vertebral artery at the craniocervical junction [2,3], whereas the North American study identifies these anomalies in less than 1 % of patients [4]. This difference has implication for the need for the preoperative vascular imaging in various ethnical groups of patients scheduled for the above-mentioned procedures.…”

Section: Introductionmentioning

confidence: 99%

Anatomical anomalies of the V3 segment of the vertebral artery in the Polish population

Fortuniak¹,

Bobeff

Polguj

et al. 2016

Eur Spine J

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“…The vertebral artery's third segment, as well as the presence of other elements, such as the venous cervical plexus, cervical nerve roots, the atlantooccipital membrane, and the dura in addition to the risk of failure related to the fixation makes every surgical manipulation critical for an optimal radiographic and clinical outcome. [1][2][3][4][5][6] Indications for C1-C2 posterior fixation include instability caused by degenerative diseases and infections, as well as trauma, tumors, congenital malformations, and os odontoideum. 6,7 Several C1-C2 posterior fixation surgical techniques and their modifications are frequently applied.…”

Section: Introductionmentioning

confidence: 99%

C1-C2 Posterior Cervical Fixation by a Harms Technique Modification

Siasios¹,

Vakharia²,

Kowalski³

et al. 2017

The Journal of Spinal Surgery

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Introduction:The unique anatomy of the upper cervical spine in conjunction with its supportive role in the axial stabilization and rotatory function of the head increases the surgical risk and associated complications for corrective surgeries performed in this spinal region. C1-C2 posterior fixation is indicated in the occurrence of instability at the craniocervical junction; and it can be performed by specific surgical techniques, such as the Harms and Magerl techniques. In this technical note, the authors present a simplified modification of the Harms technique that increases the accuracy of screw placement in the lateral mass of the C1 vertebra and in the pedicle of the C2 vertebra. This modification provides a secure path for screw placement by obtaining fluoroscopic images of K-wires inserted in the lateral masses of C1 and the pedicles of C2 as in the original technique. According to this technique, a pin driver is used to guide a K-wire through the initially marked entry point to the lateral mass of C1. After fluoroscopic confirmation of the optimal position of the guide wire, a cannulated hand drill is placed over the guidewire. A pilot hole is drilled in the same trajectory for the screw placement under fluoroscopic control. Then the guidewire and the hand drill are removed and an appropriately sized 3.5 mm polyaxial screw is placed with a hand drill under confirmation of the correct position with anteroposterior and lateral fluoroscopy. The same procedure is followed for the placement of the C2 pedicle screws. Then, a small rod is placed and secured within the polyaxial screw heads of the C1 and C2 screws bilaterally. Decortication of the spinous processes of the involved vertebrae and the occiput is the final step before closure of the fascia, cervical muscle layer, subcutaneous tissue, and skin.

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Vertebral Artery Anomalies at the Craniovertebral Junction in the US Population

Abstract: N/A

Cited by 47 publications

References 13 publications

Unilateral C-1 posterior arch screws and C-2 laminar screws combined with a 1-side C1–2 pedicle screw system as salvage fixation for atlantoaxial instability

Unilateral C-1 posterior arch screws and C-2 laminar screws combined with a 1-side C1–2 pedicle screw system as salvage fixation for atlantoaxial instability

Anatomical anomalies of the V3 segment of the vertebral artery in the Polish population

C1-C2 Posterior Cervical Fixation by a Harms Technique Modification

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