A Novel and Reproducible Classification of the Vertebral Artery in the Subaxial Cervical Spine

2019 ◽  
Vol 18 (6) ◽  
pp. 676-683
Author(s):  
Fabian Winter ◽  
Ichiro Okano ◽  
Stephan N Salzmann ◽  
Colleen Rentenberger ◽  
Jennifer Shue ◽  
...  

Abstract BACKGROUND An injury of the vertebral artery (VA) is one of the most catastrophic complications in the setting of cervical spine surgery. Anatomic variations of the VA can increase the risk of iatrogenic lacerations. OBJECTIVE To propose a novel and reproducible classification system that describes the position of the VA based on a 2-dimensional map on computed tomography angiographs (CTA). METHODS This cross-sectional retrospective study reviewed 248 consecutive CTAs of the cervical spine at a single academic institution between 2007 and 2018. The classification consists of a number that characterizes the location of the VA from the medio-lateral (ML) aspect of the vertebral body. In addition, a letter describes the VA location from the anterior-posterior (AP) aspect. The reliability and reproducibility were assessed by 2 independent raters on 200 VAs. RESULTS The inter- and intrarater reliability values showed the classification's reproducibility. The inter-rater reliability weighted κ-value for the ML aspect was 0.93 (95% CI: 0.93-0.93). The unweighted κ-value was 0.93 (95% CI: 0.86-1.00) for “at-risk” positions (ML grade ≥1), and 0.87 (95% CI: 0.75-1.00) for “high-risk” positions (ML grade ≥2). The weighted κ-value for the intrarater reliability was 0.94 (95% CI: 0.95-0.95). The unweighted κ-values for the intrarater reliability were 0.95 (95% CI: 0.91-0.99) for “at-risk” positions, and 0.87 (95% CI: 0.78-0.96) for “high-risk” positions. CONCLUSION The proposed classification is reliable, reproducible, and independent of individual anatomic size variations. The use of this novel grading system could improve the understanding and interdisciplinary communication about VA anomalies.

2021 ◽  
pp. 1-8
Author(s):  
Ichiro Okano ◽  
Stephan N. Salzmann ◽  
Fabian Winter ◽  
Erika Chiapparelli ◽  
Yushi Hoshino ◽  
...  

OBJECTIVE Medial migration of the vertebral artery (VA) can be a risk factor for injury during anterior procedures. CT angiography (CTA) has been considered the gold standard for the evaluation of various areas of the arterial anatomy. MRI and nonenhanced CT are more commonly used as routine preoperative imaging studies, but it is unclear if these modalities can safely exclude the anomalous course of the VA. The aims of this cross-sectional observational study were to investigate risk factors for medially migrated VA on CTA and to evaluate the diagnostic accuracy of MRI and nonenhanced CT for high-risk VA anatomy in the subaxial cervical spine. METHODS The records of 248 patients who underwent CTA for any reason at a single academic institution between 2007 and 2018 were reviewed. The authors included MRI and nonenhanced CT taken within 1 year before or after CTA. An axial VA position classification was used to grade VA anomalies in the subaxial cervical spine. The multivariable linear regression analysis with mixed models was performed to identify the risk factors for medialized VA. The sensitivity and specificity of MRI and nonenhanced CT for high-risk VA positions were calculated. RESULTS A total of 175 CTA sequences met the inclusion criteria. The mean age was 63.8 years. Advanced age, disc and pedicle levels, lower cervical levels, and left side were independent risk factors for medially migrated VA. The sensitivities of MRI and nonenhanced CT for the detection of grade 1 or higher VA position were only fair, and the sensitivity of MRI was lower than that of nonenhanced CT (0.31 vs 0.37, p < 0.001), but the specificities were similarly high for both modalities (0.97 vs 0.97). With the combination of MRI and nonenhanced CT, the sensitivity significantly increased to 0.50 (p < 0.001 vs MRI and vs CT alone) with a minimal decrease in specificity. CONCLUSIONS Axial images of MRI and nonenhanced CT demonstrated high specificities but only fair sensitivities. Nonenhanced CT demonstrated better diagnostic value than MRI. When combining both modalities the sensitivity improved, but a substantial proportion of medialized VAs could not be diagnosed.


2021 ◽  
Author(s):  
Tomoaki Shimizu ◽  
Masao Koda ◽  
Tetsuya Abe ◽  
Yosuke Shibao ◽  
Mamoru Kono ◽  
...  

Abstract Background A high-riding vertebral artery (HRVA) is an intraosseous anomaly that narrows the trajectory for C2 pedicle screws. The prevalence of a HRVA is high in patients who need surgery at the craniovertebral junction, but reports about HRVAs among subaxial cervical spine disorders are limited. We sought to determine the prevalence of HRVAs among patients with subaxial cervical spine disorders to elucidate the potential risk for VA injury in subaxial cervical spine surgery. Methods We included 215 patients, 94 were with a main lesion from C3 to C7 (subaxial group) and 121 were with a main lesion from T1 to L5 (thoracolumbar group). A HRVA was defined as a maximum C2 pedicle diameter of <3.5mm on axial CT. The sex, age of patients, body mass index (BMI), osteoarthritis of the atlantoaxial (C1/2) facet joints and prevalence of a HRVA in the 2 groups were compared and logistic regression was used to identify the factors correlate with a HRVA. Results The patients of subaxial group were younger than those of the thoracolumbar group but the sex and BMI didn’t differ significantly between the 2 groups. The osteoarthritis grade of C1/2 facet joints of the subaxial group was statistically higher than the thoracolumbar group. A HRVA was found in 26 patients of 94 (27.7 %) in the subaxial group and in 19 of 121 (15.7%) in the thoracolumbar group. The prevalence of a HRVA in the subaxial group was statistically higher and logistic regression analysis indicated that osteoarthritis of C1/2 facet joints significantly correlated with HRVA. Conclusions The prevalence of a HRVA in patients with subaxial cervical spine disorders is higher than in those without cervical spine disorders, and osteoarthritis of C1/2 facet joints significantly correlated with a HRVA.


Folia Medica ◽  
2019 ◽  
Vol 61 (3) ◽  
pp. 377-383
Author(s):  
Banu Alicioglu ◽  
Nadir Gulekon

Background: In the older population, tortuosity of the vertebral artery (VA), uncovertebral joint (UVJ) osteoarthritis, and abnormal vertebral alignment may alter the normal anatomy. Aim: We aimed to determine the anatomical variations and relationships between the cervical segment of the VA and the cervical spine with regard to ageing. Materials and methods: In this retrospective cross-sectional study, the computed tomography angiography scans of 110 subjects were reviewed. Any variations in the VA, UVJ degeneration were identified. The distance between the VA and uncinate process (UP) was measured electronically. The distance between the VA and UP were compared according to the age group (group A > 45, group B = 45-65, and group C > 65 years-old). Results: With regard to the transverse foramen, 7.2% of the cases had entering abnormalities of the VA, while in one case (0.83%), the right VA had an exiting abnormality (exiting from the C2 instead of the C1). UVJ degeneration was found to be significantly higher in the older age group (p > 0.05). Furthermore, at the C4-C7 levels, the distances between the VA and UP were significantly smaller in the older age group (p > 0.01). Conclusions: The VA-UP distance has been shown to decrease due to increasing UVJ osteoarthritis in the elderly. The convergence of the VA toward the spine occurs at the most mobile segment of the cervical spine, and this anatomical alteration may predispose temporary and/or permanent vertebral artery occlusion clinically, and be dangerous during cervical spine surgery.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Tomoaki Shimizu ◽  
Masao Koda ◽  
Tetsuya Abe ◽  
Yosuke Shibao ◽  
Mamoru Kono ◽  
...  

Abstract Background A high-riding vertebral artery (HRVA) is an intraosseous anomaly that narrows the trajectory for C2 pedicle screws. The prevalence of a HRVA is high in patients who need surgery at the craniovertebral junction, but reports about HRVAs in subaxial cervical spine disorders are limited. We sought to determine the prevalence of HRVAs among patients with subaxial cervical spine disorders to elucidate the potential risk for VA injury in subaxial cervical spine surgery. Methods We included 215 patients, 94 were with a main lesion from C3 to C7 (subaxial group) and 121 were with a main lesion from T1 to L5 (thoracolumbar group). A HRVA was defined as a maximum C2 pedicle diameter of < 3.5 mm on axial CT. The sex, age of patients, body mass index (BMI), osteoarthritis of the atlantoaxial (C1-2) facet joints, and prevalence of a HRVA in the 2 groups were compared and logistic regression was used to identify the factors correlated with a HRVA. Results The patients in the subaxial group were younger than those in the thoracolumbar group, but their sex and BMI did not differ significantly between the 2 groups. The mean osteoarthritis grade of the C1-2 facet joints of patients in the subaxial group was significantly higher than that in those in the thoracolumbar group. A HRVA was found in 26 patients of 94 (27.7 %) in the subaxial group and in 19 of 121 (15.7 %) in the thoracolumbar group. The prevalence of a HRVA in the subaxial group was significantly higher and osteoarthritis of C1-2 facet joints correlated significantly with a HRVA. Conclusions The prevalence of a HRVA in patients with subaxial cervical spine disorders is higher than in those without and osteoarthritis of the C1-2 facet joints is correlated with a HRVA.


2013 ◽  
Vol 19 (3) ◽  
pp. 269-278 ◽  
Author(s):  
Christopher P. Ames ◽  
Justin S. Smith ◽  
Justin K. Scheer ◽  
Christopher I. Shaffrey ◽  
Virginie Lafage ◽  
...  

Object Cervical spine osteotomies are powerful techniques to correct rigid cervical spine deformity. Many variations exist, however, and there is no current standardized system with which to describe and classify cervical osteotomies. This complicates the ability to compare outcomes across procedures and studies. The authors' objective was to establish a universal nomenclature for cervical spine osteotomies to provide a common language among spine surgeons. Methods A proposed nomenclature with 7 anatomical grades of increasing extent of bone/soft tissue resection and destabilization was designed. The highest grade of resection is termed the major osteotomy, and an approach modifier is used to denote the surgical approach(es), including anterior (A), posterior (P), anterior-posterior (AP), posterior-anterior (PA), anterior-posterior-anterior (APA), and posterior-anterior-posterior (PAP). For cases in which multiple grades of osteotomies were performed, the highest grade is termed the major osteotomy, and lower-grade osteotomies are termed minor osteotomies. The nomenclature was evaluated by 11 reviewers through 25 different radiographic clinical cases. The review was performed twice, separated by a minimum 1-week interval. Reliability was assessed using Fleiss kappa coefficients. Results The average intrarater reliability was classified as “almost perfect agreement” for the major osteotomy (0.89 [range 0.60–1.00]) and approach modifier (0.99 [0.95–1.00]); it was classified as “moderate agreement” for the minor osteotomy (0.73 [range 0.41–1.00]). The average interrater reliability for the 2 readings was the following: major osteotomy, 0.87 (“almost perfect agreement”); approach modifier, 0.99 (“almost perfect agreement”); and minor osteotomy, 0.55 (“moderate agreement”). Analysis of only major osteotomy plus approach modifier yielded a classification that was “almost perfect” with an average intrarater reliability of 0.90 (0.63–1.00) and an interrater reliability of 0.88 and 0.86 for the two reviews. Conclusions The proposed cervical spine osteotomy nomenclature provides the surgeon with a simple, standard description of the various cervical osteotomies. The reliability analysis demonstrated that this system is consistent and directly applicable. Future work will evaluate the relationship between this system and health-related quality of life metrics.


2021 ◽  
Author(s):  
Panya Luksanapruksa ◽  
Borriwat Santipas ◽  
Panupol Rajinda ◽  
Theera Chueaboonchai ◽  
Korpphong Chituaarikul ◽  
...  

Abstract Background: Incidence of subaxial spinal metastases is increasing due to longer life expectancy resulting from successful modern treatments of cancer. The three most utilized approaches for surgical treatment include the anterior, posterior, and combined approach. However, despite increasing surgical volume, data on the postoperative complication profiles of different operative approaches for this patient population is scarce.Methods: The institutional databases of two large referral centers in Thailand were retrospectively reviewed. Patients with subaxial cervical spine metastasis who underwent cervical surgery during 2005 to 2015 were identified and enrolled. Clinical presentations, baseline characteristics, operative approach, perioperative complications, and postoperative outcomes, including pain, neurological recovery, and survival, were compared among the three surgical approaches.Results: This study included 70 patients (44 anterior approach, 14 posterior approach, 12 combined approach). There were no statistically significant differences in preoperative characteristics, including Charlson Comorbidity Index(CCI), Tomita score, and revised Tokuhashi score, among the three groups. There were also no significant differences among groups for medical complications, surgical complications, neurological recovery, verbal pain score improvement, survival time, or ambulatory status improvement. However, the combined approach did show a significantly higher rate of overall perioperative complications (p=0.01), intraoperative blood loss, (p<0.001), and operative time (p<0.001) compared to the other two approaches. Conclusions: The results of this study do not reveal any clear superiority among the three main surgical approaches used to treat subaxial cervical spine metastasis. Patients in the combined approach group had the highest rates of perioperative complications. However, although the differences were not statistically significant, patients in the combined group tended to have better clinical outcomes after follow-up, and the longest survival time.


2018 ◽  
Vol 12 (1) ◽  
pp. 18-28
Author(s):  
Nirmal D Patil ◽  
Sudhir K Srivastava ◽  
Sunil Bhosale ◽  
Shaligram Purohit

<sec><title>Study Design</title><p>This was a double-blinded cross-sectional study, which obtained no financial support for the research.</p></sec><sec><title>Purpose</title><p>To obtain a detailed morphometry of the lateral mass of the subaxial cervical spine.</p></sec><sec><title>Overview of Literature</title><p>The literature offers little data on the dimensions of the lateral mass of the subaxial cervical spine.</p></sec><sec><title>Methods</title><p>We assessed axial, sagittal, and coronal computed tomography (CT) cuts and anteroposterior and lateral X-rays of the lateral mass of the subaxial cervical spine of 104 patients (2,080 lateral masses) who presented to a tertiary care public hospital (King Edward Memorial Hospital, Mumbai) in a metropolitan city in India.</p></sec><sec><title>Results</title><p>For a majority of the parameters, males and females significantly differed at all levels (<italic>p</italic>&lt;0.05). Females consistently required higher (<italic>p</italic>&lt;0.05) minimum lateral angulation and lateral angulation. While the minimum lateral angulation followed the order of C5&lt;C4&lt;C6&lt;C3, the lateral angulation followed the order of C3&lt;C5&lt;C4&lt;C6. The lateral mass becomes longer and narrower from C3 to C7. In axial cuts, the dimensions increased from C3 to C6. The sagittal cut thickness and diagonal length increased and the sagittal cut height decreased from C3 to C7. The sagittal cut height was consistently lower in the Indian population at all levels, especially at the C7 level, as compared with the Western population, thereby questioning the acceptance of a 3.5-mm lateral mass screw. A good correlation exists between X-ray- and CT-based assessments of the lateral mass.</p></sec><sec><title>Conclusions</title><p>Larger lateral angulation is required for Indian patients, especially females. The screw length can be effectively calculated by analyzing the lateral X-ray. A CT scan should be reserved for specific indications, and a caution must be exercised while inserting C7 lateral mass screws.</p></sec>


2019 ◽  
Vol 126 ◽  
pp. e1050-e1054 ◽  
Author(s):  
Chang-Hyun Lee ◽  
Jae Taek Hong ◽  
Dong Ho Kang ◽  
Ki-Jeong Kim ◽  
Sang-Woo Kim ◽  
...  

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