Prevalence of degenerative changes of the atlanto-axial joints

Surgeon Experience Is the Most Important Predictor of Case Failure Rate for Anterior Odontoid Screw Fixation: A Large Database Study

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

Determine risk factors and failure rate of anterior odontoid screw fixation surgery.

SUMMARY OF BACKGROUND DATA

Anterior odontoid screw fixation (AOSF) stabilizes type II dens fractures while preserving cervical motion. Despite having potential advantages, AOSF's failure rate and factors contributing to failure remain unknown.

MATERIALS AND METHODS

We identified AOSF patients in the national claims database Pearldiver using CPT code 22318. Failure was defined as the requirement of supplementary posterior fusion surgery in the C1-C2 or occiput-C2 region after the AOSF. We considered potential predictors of failure including age, sex, Charlson Comorbidity Index (CCI), surgeon experience, history of osteoporosis, obesity, and tobacco use. Univariate comparison analysis and logistic regression were conducted to identify factors associated with the need for additional posterior surgery.

RESULTS

For 2008 identified cases of AOSF, 249 cases (12.4%) required additional posterior fusion. Seventy-one of the 249 cases (28.5%) underwent revision surgery on the same day as the AOSF. Over 86% of revisions (215 cases) occurred within 200 days of the initial procedure. Posterior fusion rates are inversely correlated with surgeon experience, with the most experienced surgeons having a rate of 10.0%, followed by 11.5% for moderately experienced surgeons, and 15.0% for the least experienced surgeons. When comparing moderate and inexperienced surgeons to experienced surgeons, the odds ratios for posterior fusion were 1.18 ( P >0.05) and 1.61 ( P <0.006), respectively. Logistic regression revealed that both lesser experience (odds ratio=1.50) and osteoporosis (odds ratio=1.44) were the only factors significantly associated with failure ( P <0.05).

CONCLUSIONS

Our findings indicate a correlation between AOSF success and surgeon experience. While currently published results suggest higher success rates, most of this data originates from experienced surgeons and specialized centers, therefore, they may not accurately reflect the failure rate encountered in a more general practice setting.

LEVEL OF EVIDENCE

Level III.

Unilateral high-riding vertebral artery is associated with asymmetric morphological changes of the atlantoaxial joint: a novel risk factor for atlantoaxial osteoarthritis

PURPOSE

This study aimed to investigate the association between unilateral high-riding vertebral artery (HRVA) and morphological changes in the atlantoaxial joint (AAJ) and to determine whether unilateral HRVA is a risk factor for atlantoaxial osteoarthritis (AAOA).

METHODS

We conducted a retrospective analysis of 2496 patients admitted to our medical center between January 2020 and December 2022 who underwent CT imaging of the cervical spine. Two hundred and seventy-two patients with unilateral HRVA (HRVA group) were identified and a respective 2:1 age- and sex-matched control group without HRVA was built. Morphological parameters, including C2 lateral mass settlement (C2 LMS), C1/2 coronal inclination (C1/2 CI), lateral atlanto-dental interval (LADI), and C1/2 relative rotation angle (C1/2 RRA) were measured. The degree of AAOA was recorded. Risk factors associated with AAOA were identified using univariate and multivariable logistic regression analyses.

RESULTS

The study included 61.4% women, and the overall average age of the study population was 48.7 years. The morphological parameters (C2 LMS, C1/2 CI, and LADI) in AAJ were asymmetric between the HRVA and the non-HRVA sides in the HRVA group (p < 0.001). These differences in parameters (d-C2 LMS, d-C1/2 CI, and d-LADI) between the HRVA and the non-HRVA sides, and C1/2 RRA were significantly larger than those in the control group. Eighty-three of 816 patients (10.2%) with AAOA had larger values of d-C2 LMS, d-C1/2 CI, d-LADI, and C1/2 RRA compared with the patients without AAOA (p < 0.05). The multivariable logistic regression analysis indicated that unilateral HRVA [adjusted odds ratio (OR) = 2.6, 95% CI: 1.1-6.3, p = 0.029], age in the sixth decade or older (adjusted OR = 30.2, 95% CI: 16.1-56.9, p < 0.001), women (adjusted OR = 2.1, 95% CI: 1.0-5.6, P = 0.034) were independent risk factors for AAOA.

CONCLUSION

Unilateral HRVA was associated with asymmetric morphological changes of nonuniform settlement of C2 lateral mass, lateral slip of atlas, and atlantoaxial rotation displacement. Besides age ≥ 60 years and females, unilateral HRVA is an independent risk factor for AAOA.

Imaging Assessment of Nontraumatic Pathologic Conditions at the Craniovertebral Junction: A Comprehensive Review

Nontraumatic pathologic conditions of the craniovertebral junction encompass a range of conditions affecting the complex anatomy of this region without direct physical injury. These conditions include congenital syndromes that predispose individuals to ligamentous laxity, potentially leading to instability. Additionally, rare but noteworthy cases such as Grisel syndrome, a cause of pediatric torticollis, may arise without a traumatic trigger. Inflammatory diseases, including rheumatoid arthritis, ankylosing spondylitis, and crystal deposition, can lead to cervical instability and spinal cord compression. Infections at the upper cervical spine are dominated by tuberculosis, typically transmitted through hematologic or lymphatic routes with characteristic imaging findings. On the other hand, purulent bacterial infections in this area are rare. Furthermore, although tumors involving the structures of the craniovertebral junction are infrequent, they can lead to significant complications, albeit less frequently through cord compression and more commonly via pathologic fractures or subluxation. The craniocervical junction is a complex anatomic region comprising ligaments, bones, joints, and muscles that support the head's weight and enable its wide range of motion. Accurate recognition and understanding of the complex anatomy and the various nontraumatic pathologic conditions at the craniovertebral junction are pivotal for initiating timely and appropriate treatment strategies. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Myelopathy resulting from degenerative atlantoaxial subluxation

PURPOSE

To present the clinical features and treatment strategy of degenerative atlantoaxial subluxation (DAAS).

METHODS

Patients with DAAS treated in our institution from 2003 to 2020 were retrospectively reviewed. We utilized the Japanese Orthopedic Association (JOA) scale to evaluate the neurologic status and distance of Ranawat et al. (DOR) to measure vertical migration.

RESULTS

We recruited 40 patients with > 2 years of follow-up and an average age of 62.3 ± 7.7 years. All the patients had myelopathy; only one patient had moderate trauma before exacerbation of symptoms, and the duration of symptoms was 34 ± 36 months. The most frequent radiological features were vertical migration of C1 (100%), sclerosis (100%), and narrowing of the atlantoaxial lateral mass articulations (100%). Two patients underwent transoral release combined with posterior reduction and fusion, and 38 patients underwent posterior reduction and fusion with C1 lateral mass screws-C2 pedicle screws and plate systems only. Forty cases (100%) achieved a solid atlantoaxial fusion, and 38 cases (95%) achieved anatomic atlantoaxial reduction. The JOA score increased from 9.3 ± 2.6 to 14.8 ± 2.1 (P < 0.01). DOR increased from 14.5 ± 2.5 to 17.8 ± 2.2 mm at the final follow-up (P < 0.01). Loosening of the locking caps was detected in one case, bony fusion was achieved, and harvest-site pain was reported in five patients.

CONCLUSION

DAAS differs from other types of AAS and presents with anterior subluxation combined with vertical subluxation arising from degenerative changes in the atlantoaxial joints. We recommend anatomic reduction as an optimal strategy for DAAS.

Cervical Myelopathy Caused by Non-Rheumatic Retro-Odontoid Pseudotumor: An Investigation of Underlying Mechanisms and Optimal Surgical Strategy

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

This study aimed to identify the underlying pathologies of non-rheumatic retro-odontoid pseudotumors (NRPs), which would help establish an appropriate surgical strategy for myelopathy caused by NRP.

METHODS

We identified 35 patients with myelopathy caused by NRP who underwent surgery between 2006 and 2017. An age- and sex-matched control group of 70 subjects was selected from patients with degenerative cervical myelopathy. Radiographic risk factors for NRP were compared between cases and controls. We also assessed surgical outcomes following occipital-cervical (O-C) fusion, atlantoaxial (C1-2) fusion, or C1 laminectomy.

RESULTS

Patients with NRP had significantly lower C1 sagittal inner diameter, C2-7 range of motion (ROM), C2-7 Cobb angle, and C7 tilt, as well as significantly higher C1-2 ROM, atlantodental interval (ADI), and C1-2 to O-C7 ROM ratio. Multivariate regression analysis revealed that ADI, C2-7 ROM, and C7 tilt were independent risk factors for NRP. Neurological recovery and pseudotumor size reduction were comparable among surgical procedures, whereas post-operative cervical spine function was significantly lower in the O-C fusion group than in the other groups.

CONCLUSION

Non-rheumatic retro-odontoid pseudotumor was associated with an increase in ADI, suggesting that spinal arthrodesis surgery is a reasonable strategy for NRP. C1-2 fusion is preferable over O-C fusion because of the high prevalence of ankylosis in the subaxial cervical spine. Given that 29% of patients with NRP have C1 hypoplasia, such cases can be treated by posterior decompression alone. Our study highlights the need to select appropriate surgical procedures based on the underlying pathology in each case.

Dynamics of atlantoaxial rotation related to age and sex: a cross-sectional study of 308 subjects

BACKGROUND CONTEXT

Physiological ranges and dynamic changes of atlantoaxial rotation (ROTC1/2), total cervical spine rotation (ROTCs) and the percentage of ROTC1/2 from ROTCs (ROTCperc) for different age groups have not yet been investigated in a sufficiently sized cohort. Furthermore, it is not clear whether demographic variables such a sex, smoking status or diabetes affect ROTC1/2, ROTCs and ROTCperc.

PURPOSE

Obtain physiological ranges of ROTC1/2, ROTCs and ROTCperc for different age groups and determine their age-based dynamics. Investigate whether ROTC1/2, ROTCs and ROTCperc are affected by sex, smoking status or diabetes.

DESIGN

Observational cross-sectional study.

PATIENT SAMPLE

Patients undergoing elective CT examinations of the head and neck region between August 2020 and January 2022.

OUTCOME MEASURES

Ranges of motion of ROTC1/2, ROTCs and ROTCperc in degrees.

METHODS

A total of 308 subjects underwent dynamic rotational CT examinations of the upper cervical spine. Patients were divided into three age categories A1 (27-49 years), A2 (50-69 years) and A3 (≥70 years). Category A3 was further divided into B1 (70-79 years) and B2 (≥80 years). Values of ROTC1/2, ROTCs and ROTCperc were compared between all age groups, males and females, smokers and nonsmokers, diabetics a nondiabetics. Dynamics of ROTC1/2, ROTCs related to age and sex were visualized using scatterplot and trendline models.

RESULTS

ROTC1/2 significantly decreased from group A1 (64.4°) to B2 (46.7°) as did ROTCs from A1 (131.2°) to B2 (97.6°). No significant differences of ROTperc were found between groups A1-B2 with values oscillating between 49% and 51%. Smoking and diabetes did not significantly affect ROTC1/2, ROTCs and ROTCperc, females had significantly higher ROTCs than males. Males and females demonstrated a different dynamic of ROTC1/2 and ROTCs demonstrated by out scatterplot and trendline models.

CONCLUSIONS

Both ROTC1/2 and ROTCs significantly decrease with age, whereas ROTCperc remains stable. Females demonstrated higher ROTCs and their decrease of ROTC1/2 and ROTCs occurred in higher age groups compared to males. The functional repercussions atlantoaxial fusion are variable based on patient age and sex and should be taken into account prior to surgery.

Prevalence and radiographic features of atlantoaxial dislocation in adult patients with Kashin-Beck disease

PURPOSE

Kashin-Beck disease (KBD) is an endemic osteoarthropathy affecting the epiphyseal growth plate of multiple joints in young and adolescent patients. Previous studies have focused on the visible deformed extremities instead of the spinal radiological features, especially the atlantoaxial joint. The aim of this study was to determine the prevalence and radiographic features of atlantoaxial dislocation (AAD) in adult patients with KBD.

METHODS

This study was conducted on KBD patients in three typical endemic counties between October 2017 and November 2019. The patients were evaluated by collecting basic information, clinical signs and symptoms. They underwent dynamic cervical radiography, by which AAD was diagnosed. For those patients with confirmed or suspected AAD, computed tomography (CT) imaging was performed to observe the odontoid morphology and degenerative changes in the lateral atlantoaxial joints. Radiographic evaluations were reviewed to determine the prevalence and features of AAD.

RESULTS

A total of 39 (14.6%) of 267 KBD patients were diagnosed with AAD. Compared with the non-AAD patients, the detection rate of AAD was associated with a longer disease duration and stage and was not associated with age, sex or BMI. Thirty-two patients had symptoms at the neck or neurological manifestations, while seven had no symptoms. There were three types of morphologies of the odontoid process in AAD patients: separating in 19 cases, hypoplastic in 15 cases and intact in five cases. Anterior dislocation was noted in 29 cases, and posterior dislocation was noted in ten cases. Thirty-four cases were reducible, and five were irreducible. The lateral atlantoaxial joints had different severities of degenerative changes in 17 cases.

CONCLUSIONS

This study revealed that the prevalence of AAD was 14.6% in adult KBD patients. The radiographic features of AAD include manifestations of odontoid dysplasia and chronic degenerative changes in atlantoaxial joints. KBD patients with severe stages and longer disease duration were more vulnerable to the occurrence of AAD. We postulate that this atlantoaxial anomaly might originate from chondronecrosis of the epiphyseal growth plate of the odontoid process in young and adolescent individuals. This study may provide a clinical reference to help clinicians screen, prevent and treat AAD in adult patients with KBD.

Factors associated with the increased risk of atlantoaxial osteoarthritis: a retrospective study

Purpose Atlantodens osteoarthritis and atlantoaxial osteoarthritis cause neck pain and suboccipital headaches. Currently, knowledge on the risk factors for atlantoaxial osteoarthritis is lacking. This study aimed to investigate the factors related to the increased risk of atlantoaxial osteoarthritis. Methods We analyzed computed tomography (CT) images of the upper cervical spine of 1266 adult trauma patients for whom upper cervical spine CT was performed at our hospital between 2014 and 2019. The degree of atlantoaxial osteoarthritis was quantified as none-to-mild (not having osteoarthritis) or moderate-to-severe (having osteoarthritis). Risk factors associated with atlantoaxial osteoarthritis were identified using univariate and multivariable logistic regression analyses. Results The study group included 69.4% men, and the overall average age of the study population was 54.9 ± 20.4 years. The following factors were independently and significantly associated with atlantoaxial osteoarthritis in the multivariable logistic regression analysis: age in the sixth decade or older (odds ratio [OR], 20.5; 95% confidence interval [CI], 6.2‒67.2, p < 0.001), having calcific synovitis (OR, 4.9; 95% CI, 2.4‒9.9, p < 0.001), women sex (OR, 3.3; 95% CI, 1.9‒5.7, p = 0.002), and not having atlantodens osteoarthritis (OR, 2.1; 95% CI, 1.2‒3.8, p = 0.014). Conclusion In the multivariable logistic regression analysis, age in the sixth decade or older, calcification of the transverse ligament, being women, and not having atlantodens osteoarthritis were found to be significantly associated with atlantoaxial osteoarthritis. Delayed diagnosis and treatment can be avoided by focusing on these risk factors.

Surgical Management of Type II Displaced Dens Fractures Improves One-year Mortality in Elderly Patients

STUDY DESIGN

Retrospective cross-sectional analysis of US national data collected by PearlDiver Inc. database.

OBJECTIVE

To determine the rates of surgical/nonsurgical treatments and associated one-year mortality for displaced type II dens fractures without neurological deficit.

SUMMARY OF BACKGROUND DATA

Existing literature on dens fractures includes small series of patients with highly variable surgical rates. These studies contain insufficient data to determine the benefits of surgical or nonsurgical treatment as surgeon bias in treatment and selection of patients have significant effects on the results.

MATERIALS AND METHODS

Displaced type II dens fractures and upper cervical surgeries were identified using their respective International Classification of Diseases, 10th Revision (ICD-10) diagnosis and Current Procedural Terminology (CPT) codes. Inclusion criteria included patients older than 65, diagnosed with a displaced type II dens fracture, absent neurological damage, during the years 2015 to 2018. Age, sex, ICD-10 diagnosis codes, CPT codes, displacement type, and Elixhauser Comorbidity Index scores were obtained through the PearlDiver database. Patient-related variables and one-year mortality associated with surgical versus nonsurgical treatment were compared using univariate χ 2 analysis, odds ratios, and multivariate logistic regression analysis.

RESULTS

Among the 5300 patients who met our inclusion criteria, 59% (n=3108) were female, the mean age was 76.6 (±3.9) years old, and the average Elixhauser Comorbidity Index was 7.1 (±4.0). Only 8.3% (n=437) had surgical treatment for the displaced dens fracture. Multivariate logistic regression analysis for one-year mortality showed surgery was associated with decreased one-year mortality in all patients ( z =-6.26; P <0.001), patients between the ages of 65 and 74 ( z =-2.53; P =0.012), and patients over the age of 75 ( z =-5.81; P <0.001).

CONCLUSION

Despite surgery improving survival in elderly patients with type II dens fractures, surgical management is rarely pursued. Factors that independently increase the likelihood of surgery include younger age, male sex, and posterior displacement.

LEVEL OF EVIDENCE

4.

Management of fresh odontoid fractures using posterior C1-2 fixation without fusion: a long-term clinical follow-up study

OBJECTIVE

Posterior C1-2 fixation without fusion makes it possible to restore atlantoaxial motion after removing the implant, and it has been used as an alternative technique for odontoid fractures; however, the long-term efficacy of this technique remains uncertain. The purpose of the present study was to explore the long-term follow-up outcomes of patients with odontoid fractures who underwent posterior C1-2 fixation without fusion.

METHODS

A retrospective study was performed on 62 patients with type II/III fresh odontoid fractures who underwent posterior C1-2 fixation without fusion and were followed up for more than 5 years. The patients were divided into group A (23 patients with implant removal) and group B (39 patients without implant removal) based on whether they underwent a second surgery to remove the implant. The clinical outcomes were recorded and compared between the two groups. In group A, the range of motion (ROM) of C1-2 was calculated, and correlation analysis was performed to explore the factors that influence the ROM of C1-2.

RESULTS

A solid fracture fusion was found in all patients. At the final follow-up, no significant difference was found in visual analog scale score or American Spinal Injury Association Impairment Scale score between the two groups (p > 0.05), but patients in group A had a lower Neck Disability Index score and milder neck stiffness than did patients in group B (p < 0.05). In group A, 87.0% (20/23) of the patients had atlantoodontoid joint osteoarthritis at the final follow-up. In group A, the C1-2 ROM in rotation was 6.1° ± 4.5° at the final follow-up, whereas the C1-2 ROM in flexion-extension was 1.8° ± 1.2°. A negative correlation was found between the C1-2 ROM in rotation and the severity of tissue injury in the atlantoaxial region (r = -0.403, p = 0.024) and the degeneration of the atlantoodontoid joint (r = -0.586, p = 0.001).

CONCLUSIONS

Posterior C1-2 fixation without fusion can be used effectively for the management of fresh odontoid fractures. The removal of the implant can further improve the clinical efficacy, but satisfactory atlantoaxial motion cannot be maintained for a long time after implant removal. A surgeon should reconsider the contribution of posterior C1-2 fixation without fusion and secondary implant removal in preserving atlantoaxial mobility for patients with fresh odontoid fractures.

Head Pitch Angular Velocity Discriminates (Sub-)Acute Neck Pain Patients and Controls Assessed with the DidRen Laser Test

Understanding neck pain is an important societal issue. Kinematic data from sensors may help to gain insight into the pathophysiological mechanisms associated with neck pain through a quantitative sensorimotor assessment of one patient. The objective of this study was to evaluate the potential usefulness of artificial intelligence with several machine learning (ML) algorithms in assessing neck sensorimotor performance. Angular velocity and acceleration measured by an inertial sensor placed on the forehead during the DidRen laser test in thirty-eight acute and subacute non-specific neck pain (ANSP) patients were compared to forty-two healthy control participants (HCP). Seven supervised ML algorithms were chosen for the predictions. The most informative kinematic features were computed using Sequential Feature Selection methods. The best performing algorithm is the Linear Support Vector Machine with an accuracy of 82% and Area Under Curve of 84%. The best discriminative kinematic feature between ANSP patients and HCP is the first quartile of head pitch angular velocity. This study has shown that supervised ML algorithms could be used to classify ANSP patients and identify discriminatory kinematic features potentially useful for clinicians in the assessment and monitoring of the neck sensorimotor performance in ANSP patients.

Research Progress of Atlantoaxial Osteoarthritis: A Narrative Literature Review

OBJECTIVE

The purpose of this review was to consolidate the current literature related to atlantoaxial osteoarthritis (AAOA) and improve the systematic understanding of this clinical syndrome among spine surgeons.

METHODS

Articles reviewed were searched in PubMed, Ovid MEDLINE, and EMBASE using search terms: [("C1-C2" OR "C1-2" OR "atlantoaxial" OR "atlanto-axial" OR "C2" OR "C1" OR "atlas" OR "axis") AND ("osteoarthritis")]. All articles of any study design discussing on AAOA were considered for inclusion. Two independent authors read article titles, abstracts and the included appropriate articles. The relevant articles were studied in full text.

RESULTS

A total of 54 literatures were reviewed and consolidated in this narrative review. These articles are roughly divided into the following five subcategories: (1) epidemiology and etiology, (2) clinical presentation, (3) radiographic findings, (4) conservative treatment and (5) surgical indications and treatment options.

CONCLUSION

AAOA was a clinically common but often overlooked syndrome characterized by persistent occipitocervical pain. The most common cause of AAOA was joint degeneration, which was closely related to age and occupation. Initial treatment for AAOA was conservative. Atlantoaxial fusion was an option for patients with severe pain who unresponsive to conservative management.

Upper Cervical Compression Myelopathy Caused by the Retro-Odontoid Pseudotumor With Degenerative Osteoarthritis and Calcium Pyrophosphate Dihydrate Disease: A Case Report and Literature Review

The retro-odontoid pseudotumor is often concurrent with atlantoaxial subluxation (AAS). Therefore, the pseudotumor is relatively common in rheumatoid arthritis (RA) but rare in primary osteoarthritis (OA). This is a case report of an elderly male patient suffering from neck pain and compression myelopathy caused by the craniocervical pseudotumor with OA but without atlantoaxial instability. He had long-lasting peripheral and spinal pain treated by nonsteroidal anti-inflammatory drugs. Imaging found upper cervical spondylosis without AAS or dynamic instability but with periodontoid calcifications and ossifications, suggesting calcium pyrophosphate dihydrate (CPPD) crystal deposition. Based on a comprehensive literature search and review, CPPD disease around the atlantodental joint is a possible contributor to secondary OA development and retro-odontoid pannus formation through chronic inflammation, which can be enough severe to induce compression myelopathy in non-RA patients without AAS. The global increase in the aged population advises caution regarding more prevalent upper cervical spine disorders associated with OA and CPPD.

Patient-rated outcome after atlantoaxial (C1-C2) fusion: more than a decade of evaluation of 2-year outcomes in 126 patients

INTRODUCTION

Various surgical techniques have been introduced for atlantoaxial (C1-C2) fusion, the most common being Magerl's (transarticular) or the Harms/Goel screw fixation. Common indications include degenerative osteoarthritis (OA), trauma or rheumatoid arthritis (RA). Only few, small studies have evaluated patient-reported outcomes after C1-C2 fusion. We investigated 2-year outcomes in a large series of consecutive patients undergoing isolated C1-C2 fusion.

METHODS

We analysed prospectively collected data (2005-2016) from our Spine outcomes database, collected within the framework of EUROSPINE's Spine Tango Registry. It included 126 patients (34 (27%) men, 92 (73%) women; mean (SD) age 67 ± 19 y) who had undergone first-time isolated C1-C2 fusion (61% Magerl, 39% Harms(-Goel)) at least 2 years ago for OA (83 (66%)), RA (20 (16%)), fracture (15 (12%)) or other (8 (6%)). Patients completed the multidimensional Core Outcome Measures Index (COMI; 0-10) and various single item outcomes.

RESULTS

Questionnaires were returned by 118/126 (94%) patients, 2 years post-operative. Mean COMI scores showed a significant reduction from baseline: 6.9 ± 2.4 to 2.7 ± 2.5 (p < 0.0001). Overall, 75% patients achieved the MCIC of ≥ 2.2 points reduction in COMI and 88% reported a good global outcome. 91% patients were satisfied/very satisfied with their care. Self-reported complications were declared by 16% patients and further surgery at the same segment, by 2.5%.

CONCLUSION

In this large series with almost complete follow-up, C1-C2 fusion showed extremely good results. Despite the complexity of the intervention, outcomes surpassed those typically reported for simple procedures such as ACDF and lumbar discectomy, suggesting reservations about the procedure should perhaps be reviewed.

Upper cervical range of rotation during the flexion-rotation test is age dependent: an observational study

Background:

The flexion-rotation test (FRT) is widely used to detect movement dysfunction in the spinal segment C1/C2, especially in patients with cervicogenic headache. The current published literature indicates that range recorded during the FRT is not age dependent. This is questionable, considering the well documented relationship between aging and degeneration in the cervical spine and loss of cervical movement in older people. The present study therefore aims to examine the influence of age on FRT mobility, and to provide normative values for different age groups. An additional aim is to examine the influence of age on the ratio between lower and upper cervical rotation mobility.

Methods:

For this cross-sectional, observational study, healthy subjects aged from 18 to 90 years were recruited. The upper cervical range of rotation during the FRT was measured using a digital goniometer. Personal data including age, weight, height, and lifestyle factors were also assessed.

Results:

A total of 230 (124 male) healthy, asymptomatic subjects, aged between 18 and 87 years were included. Regression analysis showed that 27.91% (p < 0.0001) of the variance in FRT mobility can be explained by age alone, while 41.28% (p < 0.0001) of the variance in FRT mobility can be explained by age and total cervical range of motion (ROM). Normative values for different age decades were calculated using regression analysis. No significant influence of age on the ratio between ROM of lower and upper cervical rotation was found. There was no relevant impact of personal (gender, height, and weight) and lifestyle (smartphone and PC use) factors on ROM during the FRT.

Conclusion:

Upper cervical rotation mobility determined by the FRT correlates strongly with age; hence, the results of the FRT have to be interpreted taking into account the individual age of the tested subject. The ratio between lower and upper cervical rotation mobility is maintained in all age groups.

ABCs of the degenerative spine

Degenerative changes in the spine have high medical and socioeconomic significance. Imaging of the degenerative spine is a frequent challenge in radiology. The pathogenesis of this degenerative process represents a biomechanically related continuum of alterations, which can be identified with different imaging modalities. The aim of this article is to review radiological findings involving the intervertebral discs, end plates, bone marrow changes, facet joints and the spinal canal in relation to the pathogenesis of degenerative changes in the spine. Findings are described in association with the clinical symptoms they may cause, with a brief review of the possible treatment options. The article provides an illustrated review on the topic for radiology residents.

TEACHING POINTS

• The adjacent vertebrae, intervertebral disc, ligaments and facet joints constitute a spinal unit. • Degenerative change is a response to insults, such as mechanical or metabolic injury. • Spine degeneration is a biomechanically related continuum of alterations evolving over time.

Lateral Atlantoaxial Osteoarthritis: A Narrative Literature Review

Lateral atlantoaxial osteoarthritis (AAOA), or C1-C2 lateral mass arthritis (LMA), is an unfamiliar degenerative cervical disease with a clinical presentation that markedly differs from subaxial spondylosis. The prevalence of LMA in the nonsurgical outpatient setting is 4%. Risk factors include age and occupation. The typical patient is between 50 and 90 years old, presents with upper cervical or occipital pain, has limited rotation, and has pain provocation during passive rotation to the affected side. Pain stems from degeneration of the lateral C1-C2 articulation and may be referred or radicular, through the greater occipital nerve. Although there is no consensus on diagnostic work-up, the disease is classically seen on the open-mouth odontoid radiograph. Computerized tomography, magnetic resonance imaging, bone scan, and diagnostic injections are also useful. Initial treatment is conservative, and upwards of two-thirds of LMA patients obtain lasting relief with noninvasive measures and injections. In patients with severe, recalcitrant pain, limited C1-C2 fusion offers satisfactory and reliable relief. The goals of this review article are to provide a synthesis of the literature on LMA, to offer a treatment approach to LMA, and to identify problems with the current state of knowledge on LMA.

Osteoporosis Is the Most Important Risk Factor for Odontoid Fractures in the Elderly

Traumatic odontoid fractures (TOFs) have been described as the most common injury affecting the C-spine in the elderly. Previous studies have identified degenerative changes and bone loss as important predisposing factors. However, their interaction and respective age-adjusted impact needs further clarification. We conducted a retrospective analysis of 5303 patients (aged ≥60 years) admitted to a level I trauma center between January 2008 and January 2016 who underwent CT imaging of the C-spine. Ninety-two patients with TOF and 80 patients with other cervical spine fractures (OCSF) were identified and a respective 3:1 age- and sex-matched control group without fractures after trauma was built. In all groups, cervical bone mineral density (cBMD) was determined using phantom calibration, and degenerative changes were evaluated in a qualitative manner. In all groups, the severity of degenerative changes of the C-spine increased with age (all p < 0.05) and was inversely correlated with cBMD (all p < 0.05). cBMD was the only significant predictor of a TOF in a multivariate logistic regression model (adjusted odds ratio [OR] = 3.066, 95% confidence interval [CI] 1.432-6.563 for cervical osteoporosis). An association between odontoid cysts and TOF reached significance only in Anderson and D'Alonzo (A&D) type II TOFs (aOR = 1.383; 95% CI 1.012-1.890). Patients with OCSFs, compared with patients with TOFs, were younger (median 74 versus 83 years) and had a higher cBMD (median 208 mg/mL versus 172 mg/mL). No differences were observable when comparing cBMD and grades of degenerative changes between OCSFs and their control group (all p >0.1). Decreased cBMD is the major predisposing factor for the occurrence of TOF but not for OCSF in the elderly. The severity of odontoid cysts was found to be a cBMD-independent factor associated with A&D type II TOFs. However, degenerative changes in the odontoid neighboring joints seem to be an epiphenomenon of bone loss and older age but do not independently predispose for TOF. © 2017 American Society for Bone and Mineral Research.

Predictive Risk Factors of Cervical Spine Instabilities in Rheumatoid Arthritis: A Prospective Multicenter Over 10-Year Cohort Study

STUDY DESIGN

A prospective multicenter cohort study for more than 10 years of outpatients with rheumatoid arthritis (RA).

OBJECTIVE

To identify predictive risk factors of cervical spine instabilities, which may induce compression myelopathy in patients with RA.

SUMMARY OF BACKGROUND DATA

Many reports described the natural course of cervical spine involvement in RA. Only a few studies, however, conducted comprehensive evaluation of its prognostic factors.

METHODS

Cervical spine instability was radiographically defined as atlantoaxial subluxation with the atlantodental interval greater than 3 mm, vertical subluxation (VS) with the Ranawat value less than 13 mm, and subaxial subluxation with irreducible translation of 2 mm or higher. The "severe" category of instability was defined as atlantoaxial subluxation with the atlantodental interval of 10 mm or lower, vertical subluxation with the Ranawat value of 10 mm or higher, and subaxial subluxation with translation of 4 mm or higher or at multiple levels. Of 503 "definite" or "classical" patients with RA without baseline "severe" instability, 143 were prospectively followed throughout for more than 10 years. The Cox proportional hazards regression analysis was performed to determine predictors for the development of "severe" instabilities. To exclude biases from the low follow-up rate, similar assessments were performed in 223 patients followed for more than 5 years from baseline.

RESULTS

The incidence of cervical spine instabilities and "severe" instabilities significantly increased during more than 10 years in both 143 and 223 cohorts (all P < 0.01). Multivariable Cox proportional hazards models found that baseline mutilating changes (hazard ratio [HR]=19.15, 95% confidence interval [95% CI] = 3.96-92.58, P < 0.01), corticosteroid administration (HR = 4.00, 95% CI = 1.76-9.11, P < 0.01), and previous joint surgery (HR = 1.99, 95% CI = 1.01-3.93, P = 0.048) correlated with the progression to "severe" instability in 143 cases and also in 223 cases (HR = 8.12, 95% CI = 2.22-29.64, P < 0.01; HR = 3.31, 95% CI = 1.68-6.53, P < 0.01; and HR = 2.07, 95% CI = 1.16-3.69, P = 0.014, respectively).

CONCLUSION

Established mutilating changes, concomitant corticosteroid treatment, and previous joint surgery are relatively robust indicators for a poor prognosis of the cervical spine in patients with RA, based on the consistency in more than 10-year analysis of two different settings.

LEVEL OF EVIDENCE

3.

Outcomes Following Arthrodesis for Atlanto-Axial Osteoarthritis

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

We set out to evaluate the radiographic and patient-reported outcomes following C1-C2 arthrodesis for atlantoaxial osteoarthritis (AAOA) using modern instrumentation and techniques.

SUMMARY OF BACKGROUND DATA

Few studies have evaluated outcomes following C1-C2 arthrodesis for AAOA using modern surgical fixation techniques.

METHODS

Retrospective analysis of all patients following C1-C2 arthrodesis with recalcitrant AAOA from a single center, single surgeon from 2002 to 2012. Preoperative, immediate and final follow-up postoperative radiographic images were evaluated. Patient-reported outcomes scores were assessed preoperative, 1-year, and final postoperative follow-up.

RESULTS

We found a total of 14 patients (13 female, 1 male) with average follow-up of 2.96 ± 2.26 years and mean age at surgery of 71.8 ± 9.3 years old. The most common construct was posterior C1-C2 bilateral screw-rod construct (SRC) (n = 9), and there were 3 patients with transarticular screw (TAS) constructs, and 2 patients with hybrid fixation (unilateral SRC and contralateral TAS). Mean change from baseline to final follow-up for Numeric Pain Rating Scale (NRS) was -4.7 ± 2.1, and Neck Disability Index (NDI) was -21.0 ± 13.6, with 11 (78.6%) patients demonstrated a substantial clinical benefit (change in NDI ≥ 10). There were no differences from baseline to all follow-up time points for SF-12 Physical and Mental Component Scores. All patients had evidence of solid C1-C2 arthrodesis and stable fixation at final follow-up, with no significant change in subaxial sagittal alignment. There were no perioperative or postoperative complications.

CONCLUSION

We report one of the largest series evaluating patient-reported outcomes in patients following arthrodesis for AAOA using modern C1-C2 fixation techniques. Our study found C1-C2 arthrodesis for AAOA to be safe and effective, with a significant improvement in patient-reported pain and neck disability and most patients reporting substantial clinical benefit.

LEVEL OF EVIDENCE

4.

Incidence and age and gender profiles of hyperplasia in individual cervical vertebrae

Objective

To analyze the incidence and age and gender profiles of hyperplasia in individual cervical vertebrae.

Methods

In this retrospective study, computed tomography three-dimensional reconstruction images of cervical vertebrae from patients with neck discomfort were analyzed for the presence of hyperplasia and compared with age and gender data.

Results

Scans from a total of 580 patients (352 males, 228 females) were analyzed. The highest incidence of hyperplasia was seen in C2 (25%), followed by C1 (23%), C6 (16%), C5 (15%), C7 (9%), C4 (8%) and C3 (4%). Patients with C2 hyperplasia were the youngest and those with C1 hyperplasia were the second youngest, while patients with C7 hyperplasia were the oldest. Of those with C2, C1 and C7 hyperplasia, males were significantly younger than females, whereas of those with C3, C4, C5 and C6 hyperplasia, females were significantly younger than males.

Conclusions

Hyperplasia of the cervical spine shows different age and gender profiles among the seven vertebrae. These findings may be helpful for the early recognition of cervical hyperplasia and highlight the importance of protecting the atlanto-axial joint in daily life.