Prevalence of Vertebral artery anomaly in upper cervical and its surgical implications: a systematic review

Anatomical Relationships of Internal Carotid Artery with Posterior Pharyngeal Wall and Upper Cervical Spine: Analysis of 238 Computed Tomography Angiograms

OBJECTIVE

To evaluate internal carotid artery's (ICA) anatomical relationships with atlantoaxial joints and posterior pharyngeal wall and to illustrate ICA injury risk during transoral procedures to the upper cervical spine.

METHODS

Cervical spine computed tomography angiography of 238 patients was retrospectively evaluated. Each ICA was classified into 1 of 3 zones: areas medial (Zone 1), anterior (Zone 2), or lateral (Zone 3) to the atlantoaxial joint. For an ICA in Zone 1, the shortest distances to the posterior pharyngeal wall and midsagittal plane were measured. For an ICA in Zone 2, the closest distances to the midsagittal plane and anterior cortex of the C1-2 complex were measured.

RESULTS

Fifteen ICAs in Zone 1 were found in 12 (5%) patients, with 3 female patients having bilateral ICAs medial to the atlantoaxial joint. The incidence of ICA in Zone 1 was higher in females than in males. In cases of ICAs in Zone 2, the ICAs were close to the anterior cortex of the C1-2 complex, with the shortest distance being 2.6 ± 1.5 mm. A total of 39.9% of patients had bilateral ICAs in Zone 3.

CONCLUSIONS

Transoral surgeries in the upper cervical spine carry potential ICA injury risk. They should be carefully deliberated in patients whose ICAs are in Zone 1. In cases of ICAs in Zone 2, meticulous subperiosteal stripping and gentle traction should be performed on the posterior pharyngeal wall. Preoperative identification of the course of ICAs is mandatory in patients undergoing transoral surgeries in the upper cervical spine.

The impact of an anomalous third segment of the vertebral artery on bypass surgery: a case report and literature review

The horizontal part of the third segment (V3) of the vertebral artery (VA) is a critical anastomotic site for bypass procedures involving either donor or recipient vessels. It is rare for the V3 segment to deviate from its typical course of passing through the atlanto-transverse foramen. V3 anomaly encountered in occipital artery (OA)-V3 bypass surgery has not been previously reported. Here, we present a case involving a patient undergoing bypass surgery due to recurrent post-stent occlusion at the first segment (V1) of the left VA. During the operation, it was noted that the V3 horizontal segment could not be identified within the left VA groove, leading to initial suspicion of left V3 disuse atrophy attributed to prolonged chronic ischaemia. Consequently, there was a need to modify the operative method and to transition from an OA-V3 bypass to an OA-posterior inferior cerebellar artery bypass. Post-operative computed tomography angiography confirmed that indeed, the left V3 did not traverse through the transverse foramen of the atlas and instead entered the dural membrane between the first cervical vertebra (C1) and the second cervical vertebra (C2).

Unilateral C1-C2 Posterior Fusion in a Patient With Right Vertebral Artery Anomaly With Intracanal Trajectory: A Case Report

CASE

A 59-year-old woman presented with progressively worsening neck pain and radicular symptoms. Cervical radiographs revealed C1-C2 dynamic instability. Magnetic resonance imaging and computed tomographic angiogram revealed an anomalous right vertebral artery with intracanal trajectory at C1. A unilateral left C1-C2 fusion with a C1 lateral mass screw and C2 transarticular screw placement was performed due to the anomalous artery. At 14-month follow-up, the patient's cervical symptoms had resolved.

CONCLUSION

In this patient with an aberrant vertebral artery who was indicated for C1-C2 fusion, a unilateral contralateral fusion with a C1 lateral mass screw and C2 transarticular screw was a satisfactory treatment option.

Prevalence of anatomical variations at the suboccipital (V3) segment of the vertebral artery: a systematic review

BACKGROUND AND OBJECTIVE

A recent meta-analysis on the incidence of iatrogenic injury to the VA has revealed that patients with variant anatomy are more prone to iatrogenic injury. Therefore, this review is designed to investigate the incidence of variations in the suboccipital component of the vertebral artery in different population groups according to the available literature.

METHODS

This systematic review was conducted according to PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The review is based on a comprehensive and extensive search of PubMed, Google Scholar, and ResearchGate. The following search terms were used: "vertebral artery" AND "suboccipital segment" AND "anomalies/anatomical variations of the V3 segment." Reference lists of all extracted articles were also extensively searched for references to any further relevant publications.

RESULTS

A total of 17 papers met the inclusion criteria. The 17 studies corresponded to a total of 10,820 patients. A persistent first intersegmental artery was registered in 1.8% (197 out of 10,820) of the patients. Extradural PICA origin was observed in 1.6% (175 out of 10,820) of the patients. Fenestration was detected in 0.7% (72 out of 10,820) of the patients.

CONCLUSION

The authors summarize the incidence of vascular variation at the suboccipital segment of the VA in different population groups across the Asian, European, American, and African continents. Awareness of the extent of possible anatomical variation will help interpret radiographs, which will enhance the identification of vascular pathologies and reduce the risk of iatrogenic injury.

Properties and Implementation of 3-Dimensionally Printed Models in Spine Surgery: A Mixed-Methods Review With Meta-Analysis

OBJECTIVE

Spine surgery addresses a wide range of spinal pathologies. Potential applications of 3-dimensional (3D) printed in spine surgery are broad, encompassing education, planning, and simulation. The objective of this study was to explore how 3D-printed spine models are implemented in spine surgery and their clinical applications.

METHODS

Methods were combined to create a scoping review with meta-analyses. PubMed, EMBASE, the Cochrane Library, and Scopus databases were searched from 2011 to 7 September 2021. Results were screened independently by 2 reviewers. Studies utilizing 3D-printed spine models in spine surgery were included. Articles describing drill guides, implants, or nonoriginal research were excluded. Data were extracted according to reporting guidelines in relation to study information, use of model, 3D printer and printing material, design features of the model, and clinical use/patient-related outcomes. Meta-analyses were performed using random-effects models.

RESULTS

Forty articles were included in the review, 3 of which were included in the meta-analysis. Primary use of the spine models included preoperative planning, education, and simulation. Six printing technologies were utilized. A range of substrates were used to recreate the spine and regional pathology. Models used for preoperative and intraoperative planning showed reductions in key surgical performance indicators. Generally, feedback for the tactility, utility, and education use of models was favorable.

CONCLUSIONS

Replicating realistic spine models for operative planning, education, and training is invaluable in a subspeciality where mistakes can have devastating repercussions. Future study should evaluate the cost-effectiveness and the impact spine models have of spine surgery outcomes.

Bilateral vertebral artery fenestrations in the craniocervical junction region: the clinical role of 3D computed tomography angiography

Fenestration of the vertebral artery (FVA) is a rare occurrence that comprises only 2% of fenestrations formed in the intracranial arteries. Herein, we report a unique case of bilateral FVA in the craniocervical junction (CCJ) region using conventional magnetic resonance angiography (MRA) and three-dimensional computed tomography angiography (3D-CTA). Compared to MRA, 3D-CTA was more sensitive in delineating the FVAs located in the region. Furthermore, it effectively depicted the relationships between the VAs and surrounding bony structures. The clinical implications of FVAs can be better understood in relation to the surrounding bony structures. 3D-CTA is mandatory when performing endovascular and open surgical interventions in and around the VA segments in the CCJ region.