Cervical degenerative spondylolisthesis: analysis of facet orientation and the severity of cervical spondylolisthesis

Cervical facet joint degeneration, facet joint angle and paraspinal muscle degeneration are correlated with degenerative cervical spondylolisthesis at C4/5: a propensity score-matched study

BACKGROUND CONTEXT

Prior studies have hypothesized that degenerative cervical spondylolisthesis (DCS) may be influenced by loss of stability due to disc, facet joint or cervical alignment. Meanwhile, it is commonly believed that the facet joints and paraspinal muscles participate in maintaining cervical spine stability. However, the impact of paraspinal muscle morphology and detailed facet joint features on DCS requires further investigation.

PURPOSE

To compare facet joint characteristics, disc degeneration and muscle morphology between patients with DCS and those without DCS.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Consecutive surgical patients with degenerative cervical spondylosis from June 2016 to August 2023 were recruited.

OUTCOME MEASURES

DCS was assessed on X-ray based on the translation distance. Cervical facet joint degeneration (CFD), the facet joint angle on the axial plane (FA-A) and the facet joint angle on the sagittal plane (FA-S), and facet joint tropism (FT) were measured on computerized tomography (CT). Paraspinal muscle degeneration was assessed on magnetic resonance imaging (MRI) including by the adjusted cross-sectional area (aCSA), the functional aCSA, the fat infiltration ratio (FI%). The Pfirrmann grade of the cervical disc was also evaluated.

METHODS

Demographic and clinical data were compared in matched and unmatched cohorts. Disc degeneration, muscle degeneration and facet joint characteristics, including FA, FT and CFD, were compared between patients with and without DCS. Furthermore, the degree of CFD was compared with that of adjacent segments in both groups. Additionally, logistic regression was performed to determine independent risk factors for DCS. Finally, the receiver operating characteristic (ROC) curve, area under the curve (AUC) and cutoff value for the risk factors were calculated.

RESULTS

A total of 431 surgical patients were propensity score matched for age, sex and BMI, and 146 patients were included in the final analysis, with 73 patients in the DCS group and 73 patients in the non-DCS group. DCS patients exhibited more severe CFD at C4/5 (segment with spondylolisthesis). Additionally, DCS was generally associated with more severe CFD, a more horizontal FA-S, more FT and worse paraspinal muscle health but similar disc degeneration. In addition, anterior spondylolisthesis was related to more severe CFD and decreased functional aCSA of the flexors and extensors. Finally, more severe CFD, a more horizontal FA-S and a higher FI% on deep extensor were revealed to be risk factors for DCS, with cutoff values of 1.5, 44.5̊, and 37.1%, respectively.

CONCLUSIONS

This study demonstrated that CFD, the FA and FT and parasipnal muscle degeneration were associated with DCS. And may provide novel insight into the pathogenesis and nature history of DCS and suggest the evolution of degeneration in the cervical spine.

Exploration of the correlation between facet joints cross-sectional area asymmetry and cervical disc herniation

PURPOSE

To evaluate the association between facet joints cross-sectional area asymmetry (FCAA) and cervical intervertebral disc herniation (CDH).

METHODS

Overall, we retrospectively recruited 390 consecutive patients with CDH who underwent surgical treatment at our institution and 50 normal participants. Clinical variables and radiological findings related to CDH were collected.

RESULTS

Patients with CDH were more likely to have a higher absolute value of the facet asymmetry factor (FAF) (p  < .001), in which the FAF value of the left group was significantly higher than the other groups (p  < .001) and the right group was lower than the central group (p  < .001). 9.62% (C3/4), 12.19% (C4/5), 8.70% (C5/6), and 8.14% (C6/7) were determined as cutoff values for each variable that maximized sensitivity and specificity. Furthermore, multivariate analysis showed that cross-sectional area asymmetry of the facet joint (FCAA) was an independent risk factor for the occurrence of CDH. Also, the Chi-square test showed a significant difference in the distribution of the degeneration classification of the disc between the facet-degenerated group and the nondegenerated group at C5/6 (p = 0.026) and C6/7 (p = 0.005) in the facet asymmetry (FA) group.

CONCLUSIONS

FCAA is evaluated as an independent risk factor for CDH and associated with the orientation of disc herniation. And facet joint orientation may also play a role in cervical spine degeneration rather than facet joint tropism.

A high-quality dataset featuring classified and annotated cervical spine X-ray atlas

Recent research in computational imaging largely focuses on developing machine learning (ML) techniques for image recognition in the medical field, which requires large-scale and high-quality training datasets consisting of raw images and annotated images. However, suitable experimental datasets for cervical spine X-ray are scarce. We fill the gap by providing an open-access Cervical Spine X-ray Atlas (CSXA), which includes 4963 raw PNG images and 4963 annotated images with JSON format (JavaScript Object Notation). Every image in the CSXA is enriched with gender, age, pixel equivalent, asymptomatic and symptomatic classifications, cervical curvature categorization and 118 quantitative parameters. Subsequently, an efficient algorithm has developed to transform 23 keypoints in images into 77 quantitative parameters for cervical spine disease diagnosis and treatment. The algorithm's development is intended to assist future researchers in repurposing annotated images for the advancement of machine learning techniques across various image recognition tasks. The CSXA and algorithm are open-access with the intention of aiding the research communities in experiment replication and advancing the field of medical imaging in cervical spine.

A possible correlation between facet orientation and development of degenerative cervical spinal stenosis

BACKGROUND

Previous studies have demonstrated the relationship between sagittal facet orientation and cervical degenerative spondylolisthesis. However, the associations between facet orientation and cervical spinal stenosis (CSS) have rarely been studied.

METHODS

One hundred twenty patients with CSS (CSS group) and 120 healthy participants (control group) were consecutively enrolled. The cervical facet angles and anteroposterior diameter (A-P diameter) of spinal canal at each subaxial cervical levels were measured using axial magnetic resonance imaging. The intersection angle of the midsagittal line of the vertebra to the facet line represents the orientation of the facet joint.

RESULTS

The facet angles on the right side at C2- C3 and C3-C4 in CSS group and at C2- C3 in control group had significantly higher values than those of the other sides. Besides, the facet angles and A-P diameter of spinal canal in CSS group were significantly smaller than those in control group at all levels (p < 0.05).

CONCLUSIONS

Our study demonstrated that patients with CSS have smaller axial cervical facet joint angles compared to the healthy individuals. Further studies are needed to elicit the specific underlying mechanism between sagittalization of the cervical facet joints and the pathology of CSS.

Significance of Facet Fluid Index in Anterior Cervical Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective cohort study.

PURPOSE

To correlate cervical facet fluid characteristics to radiographic spondylolisthesis, determine if facet fluid is associated with instability in cervical degenerative spondylolisthesis, and examine whether vertebral levels with certain facet fluid characteristics and spondylolisthesis are more likely to be operated on.

OVERVIEW OF LITERATURE

The relationship between facet fluid and lumbar spondylolisthesis is well-documented; however, there is a paucity of literature investigating facet fluid in degenerative cervical spondylolisthesis.

METHODS

Patients diagnosed with cervical degenerative spondylolisthesis were identified from a hospital's medical records. Demographic and surgical characteristics were collected through a structured query language search and manual chart review. Radiographic measurements were made on preoperative MRIs for all vertebral levels diagnosed with spondylolisthesis and adjacent undiagnosed levels between C3 and C6. The facet fluid index was calculated by dividing the facet fluid measurement by the width of the facet. Bivariate analysis was conducted to compare facet characteristics based on radiographic spondylolisthesis and spondylolisthesis stability.

RESULTS

We included 154 patients, for whom 149 levels were classified as having spondylolisthesis and 206 levels did not. The average facet fluid index was significantly higher in patients with spondylolisthesis (0.26±0.07 vs. 0.23±0.08, p <0.001). In addition, both fluid width and facet width were significantly larger in patients with spondylolisthesis (p <0.001 each). Cervical levels in the fusion construct demonstrated a greater facet fluid index and were more likely to have unstable spondylolisthesis than stable spondylolisthesis (p <0.001 each).

CONCLUSIONS

Facet fluid index is associated with cervical spondylolisthesis and an increased facet size and fluid width are associated with unstable spondylolisthesis. While cervical spondylolisthesis continues to be an inconclusive finding, vertebral levels with spondylolisthesis, especially the unstable ones, were more likely to be included in the fusion procedure than those without spondylolisthesis.

Effects of lumbar-pelvic training combined with electroacupuncture on chronic nonspecific low back pain

This observational study was conducted to investigate the effect of lumbar-pelvic training (LP) combined with electroacupuncture (EA) in the treatment of chronic nonspecific low back pain. One hundred and twenty patients diagnosed with chronic nonspecific low back pain were evenly randomized to receive the following 4 treatments for 2 weeks: LP combined with EA (Group A), EA (Group B), LP (Group C) or no intervention (Group D). The LP was a self-developed training program containing 5 movements and was conducted three times a week to build up the strength of abdomen muscle groups. Four acupoints along the foot-taiyang bladder meridian and the governor vessel were chosen for EA five times a week based on the theory of Traditional Chinese Medicine. The Visual Analog Scale and Oswestry Disability Index were measured before and after treatment to assess the reduction of pain intensity and functional disability, respectively. Following the treatments, Visual Analog Scale and Oswestry Disability Index scores in all 3 intervention groups were significantly lower than those in the Group D without intervention (P < .01). Among the intervention groups, Group A's scores were lower than those of Group B or Group C (P < .01). The overall efficacy of Group A was 93.33%, which was higher than that of Group B (76.67%) and Group C (70.00%) (P < .01). In conclusion, this study suggest that our self-developed lumbar-pelvic training combined with electroacupuncture is effective for chronic nonspecific low back pain in terms of pain and disability reduction.

Investigating the mechanical effect of the sagittal angle of the cervical facet joint on the cervical intervertebral disc

BACKGROUND

Facet tropism is defined as the asymmetry between the left and right facet joints relative to the sagittal plane. Published clinical studies have found that facet tropism is associated with cervical disc herniation. However, the relationship between the facet orientation and the side of cervical disc herniation remains controversial. Therefore, this study used the finite-element technique to investigate the biomechanical effects of the sagittal angle of the cervical facet joints on the cervical intervertebral disc.

OBJECTIVE

The biomechanical effects of the sagittal angle of the cervical facet joint on the cervical disc and facet joint were investigated using the finite-element technique.

METHODS

The finite-element model was constructed using computed tomography scans of a 26-year-old female volunteer. First, a cervical model was constructed from C3 to C7. The model was verified using data from previously published studies. Second, the facet orientation at the C5-C6 level was altered to simulate different sagittal angles of cervical facet joints. Five models, F70, F80, F90, F100, and F110, were simulated with different facet joint orientations (70°, 80°, 90°, 100°, and 110° facet joint angles at the left side, respectively, and 90° facet joint angles at the right side) at the C5-C6 facet joints. In each model, annular fibres stress and facet cartilage pressure were studied under six pure moments and two combined moments.

RESULTS

Comparing the stress of the annulus fibres in flexion combined with right axial rotation and in flexion combined with left axial rotation in the same model, no difference in the maximum stress of the annulus fibres was noted between these two different moments in the F90 model, whereas differences of 12.80%, 8.84%, 14.95% and 33.32% were noted in the F70, F80, F100 and F110 models, respectively. The same trend was observed when comparing the maximum stress of the annulus fibres in each model during left and right axial rotation. No differences in annular fibres stress and facet cartilage pressure were noted among the five models in flexion, extension, lateral bending, left axial rotation, and flexion combined with left axial rotation in this study. However, compared with the F70 model in flexion combined with right axial rotation, the annulus fibres stress of the F80, F90, F100, and F110 models increased by 5.53%, 13.03%, 35.04%, and 72.94%, respectively, and the pressure of the left facet joint of these models decreased by 5.65%, 12.10%, 18.41%, and 25.74%, respectively. The same trend was observed in the right axial moment.

CONCLUSION

Facet tropism leads to unbalanced stress distribution on the annulus fibres at the cervical intervertebral disc. The greater the sagittal angle of the facet joint, the greater the annular fibres stress on this side. We hypothesised that the side with the larger sagittal angle of the facet joint exhibits a greater risk of disc herniation.

Effect of Facet Tropism on Postoperative Cervical Range of Motion After Single-Level Cervical Disc Arthroplasty

STUDY DESIGN

Retrospective analysis.

OBJECTIVES

Cervical disc arthroplasty (CDA) was designed to replace the degenerated disc with the prosthesis to preserve cervical motion. The commonly used artificial discs are designed symmetric, whereas the facet joints were reported to be asymmetric in many people. This study aimed to evaluate the effect of facet tropism on the cervical range of motion (ROM) after single-level CDA using Prestige LP.

METHODS

A total of 90 patients who underwent single-level CDA using Prestige LP from 2012 to 2017 were retrospectively reviewed. Radiographs were taken at each time point to measure the C2-C7 ROM and the ROM at the surgical segment. The pre-operation CT scans were utilized to reconstruct and calculate the angular direction of facet joints with respect to transverse, coronal, and sagittal reference planes. Facet tropism above 7° was defined as facet joint asymmetry.

RESULTS

No significant difference was found in flexion-extension C2-C7 ROM or ROM at the surgical segment between patients with symmetric and asymmetric fact joints regarding the sagittal plane. Patients with coronal asymmetric facet joints had lower flexion-extension ROM at the surgical level. Patients with transverse asymmetric facet joints had both lower flexion-extension C2-C7 ROM and ROM at the surgical level. After CDA surgery, patients obtained good clinical outcomes including increased Japanese Orthopedic Association (JOA) and decreased Neck Disability Index (NDI) as well as Visual Analogue Scale (VAS).

CONCLUSION

The coronal and transverse tropism seemed to be correlated with decreased flexion-extension ROM after CDA using Prestige LP.

The Posterolaterally Oriented and Laterally Downward Sloping Facet Joint Is a Risk Factor for Degenerative Cervical Spondylolisthesis and Myelopathy

Introduction

Facet joints are anatomical structures that are known to be crucial for determining spinal biomechanical motion; however, the potential relationship between facet orientation and the development of cervical spondylolisthesis remains unclear. Thus, in this study, we aimed to explore the relationship between facet orientation and cervical spondylolisthesis as well as myelopathy.

Methods

Facet orientation in the cervical spine was investigated using computed tomography in 103 patients with cervical myelopathy, and facet inclination was measured on axial, coronal, and sagittal reconstructed images. Patients were divided into anterolisthesis, retrolisthesis, and no spondylolisthesis groups at each intervertebral level (C2/3-C6/7 levels).

Results

Facet joints in the anterolisthesis and retrolisthesis groups tended to slope posterolaterally and downward laterally compared with those in the no spondylolisthesis group at C3/4, C4/5, and C5/6 levels (P<0.001).

Conclusions

The posterolaterally oriented and laterally downward sloping facet at C3/4 and C4/5 levels may be a risk factor for the development of cervical spondylolisthesis as well as symptomatic myelopathy.

Evaluation the association of facet tropism in multi-sports athletes with cervical disc hernia

Background

Facet tropism (FT) can be defined as the angular difference between the orientation of the right and left facet joints in axial or sagittal planes. Most studies discuss about the relationship with lumbar disc hernia and facet joint angle. However, little is known about the association of facet tropism with disc herniation in the cervical spine in multisports athletes. In this study, We aimed to investigate the relationship between cervical facet tropism and disc hernia in athletes of different branches between the ages of 20–40 from the cervical MR images of the cases.

Methods

This is a retrospective study performed on athletes who applied our hospital between January 2014–2019 with neck pain and have MR imaging of the cervical spine. Cervical MR images of the patients were evaluated by an experienced radiologist from the hospital system database and archives. 79 cases (52 men and 27 women) were included in the study.

Results

No statistically significant difference was found between the facet joint angles of both groups at all levels (p˃0.05). Only left C6-7 disc angles of CDH group were measured as 92.99° ± 10.77⁰ (62⁰–113⁰) and 88.58° ± 7.65° (67°-110°) for the normal group and this difference was found statistically significant (p = 0.007).

Conclusion

In this study, we did not predict that cervical facet tropism may be a factor associated with cervical disc hernia in young athletes with CDH.

Facet tropism: Association between cervical disc degeneration and cervical spondylotic radiculopathy in middle-aged patients

This study aimed to retrospectively explore the relationship between facet tropism (FT) and cervical disc degeneration in cervical spondylotic radiculopathy (CSR) patients on 3-dimensional views. A total of 180 middle-aged patients with single-level CSR at C4/5 who underwent cervical CT and MRI in our hospital were included. The incidence of FT (or called FT (+), defined as FT ≥ 7 degree) at C3/4, C4/5, C5/6 levels were measured and calculated by reconstructed CT images on 3-dimensional views. The grade of cervical disc degeneration at three levels was assessed by MRI images by the method of Miyazali. Univariate analysis was performed to compare their cervical disc degeneration grade and CSR incidence between two groups stratified by FT (+). Moreover, a logistic regression model was used to investigate the association between FT (+) and grade of cervical disc degeneration and incidence of CSR adjusting for age, gender, and BMI. Grade of cervical disc degeneration and incidence of CSR in axial FT (+) group were both significantly increased compared to axial FT (-) group, while sagittal and coronal FT (+) groups showed no difference. Axial FT (+) was significantly associated with the grade of cervical disc degeneration and incidence of CSR. in middle-aged patients with CSR, axial FT (+) might be the risk factor for cervical disc degeneration but not sagittal and coronal FT (+). Also, axial FT (+) was positively associated with CSR incidence. Therefore, axial FT might play a vital role in the progression of cervical disc degeneration and CSR occurrence.

Cervical facet joint effusion: A sign of instability in cervical degenerative spondylolisthesis

Aims:

The aim of this study was to trace the association between cervical facet joint effusion and cervical degenerative spondylolisthesis (CDS). CDS has not received as much attention as its lumbar counterpart. Identification of features of instability on magnetic resonance imaging (MRI) is crucial to avoid missing presence of CDS.

Materials and Methods:

The authors retrospectively reviewed cervical spine MRI scans and upright lateral flexion-extension radiographs of 17 consecutive patients at a single institution between January 2017 and June 2018 that revealed CDS. Presence of cervical facet joint effusion and CDS was recorded. Data were analyzed to deduce possibility of an association between cervical facet joint effusion and CDS.

Results:

Seventeen patients fulfilled the inclusion criteria of cervical spondylotic myelopathy associated with CDS. Out of these, 10 patients revealed facet joint effusion at C3-C4 (4 patients) and C4-C5 (6 patients) levels. The mean age of patients was 65.8 years (49–79) and M:F was 2.2:1. Amount of facet joint effusion varied and ranged from 1.6 mm to 4.7 mm on the axial images. Ten patients (58.82%) demonstrated facet joint effusion associated with mobile CDS. Seven patients (41.17%) with CDS and without facet effusion did not demonstrate mobility of more than 0.5 mm in flexion-extension radiographs.

Conclusion:

The current study acknowledges the association of “cervical facet effusion” and CDS. Clinically measurable facet joint effusion on MRI suggests the need for further attempts to diagnose CDS.

The Correlation Between Facet Tropism and Intervertebral Disc Herniation in the Subaxial Cervical Spine

STUDY DESIGN

A retrospective case-control study.

OBJECTIVE

Investigating the correlation between the facet tropism (FT) and subaxial cervical disc herniation (CDH).

SUMMARY OF BACKGROUND DATA

Although debatable, it was widely reported that FT was associated with lumbar disc herniation. However, the exact correlation between FT and subaxial CDH is still unclear.

METHODS

Two-hundred patients with any disc herniation at C3/4, C4/5, C5/6, or C6/7 and 50 normal participants without CDH (normal control group) were included in this study. For patients, the cervical levels with CDH and the levels without herniation were classified into the "herniation group" and "patient control group," respectively. Bilateral facet joint angles at C3/4, C4/5, C5/6, and C6/7 on sagittal, axial, and coronal planes were measured on computed tomography (CT). The disc degeneration at each level was assessed on magnetic resonance imaging (MRI).

RESULTS

Both the mean difference between left and right facet angles and tropism incidence in herniation group were significantly greater than those in two control groups whenever at C3/4, C4/5, C5/6, or C6/7 level and whenever on sagittal, axial, or coronal plane. The mean differences of angles and tropism incidences in most patient control groups were not significantly greater than those of corresponding normal control groups. The incidence of greater facet angle at the left or right side was not significantly different among the left, central, and right herniation groups. The mean disc degeneration grades in both herniation and patient control groups were significantly higher than those in normal control groups while no difference between herniation and patient control groups.

CONCLUSION

The FT on the sagittal, axial, and coronal planes are all associated with CDH in the subaxial cervical spine. The greater facet angle at the left or right side does not affect the side of herniation. The severity of cervical disc degeneration is not associated with FT.Level of Evidence: 3.

Facet Tropism in Lumbar Spine and Cervical Spine: A Systematic Review and Meta-Analysis

BACKGROUND

Facet tropism (FT) refers to the difference in the orientation of facet joints with respect to each other in the sagittal plane. FT leads to unequal biomechanical forces on facet joint and intervertebral disc during rotation and other physiologic movements. Most of the studies have reported the incidence of FT in the lumbar spine to vary between 40% and 70%, with L4-5 level being the most commonly afflicted level. The objective of this study was to find the association between FT and various lumbar and cervical degenerative disorders.

METHODS

A systematic search of PubMed was performed with the keywords "facet tropism" and "facet asymmetry." Data for meta-analysis were extracted from the studies to obtain pooled impact of FT on lumbar disc herniation (LDH) and lumbar degenerative spondylolisthesis (LDS).

RESULTS

Eighty-two articles were included in the systematic review and 18 studies had the required data to be included in the meta-analysis. The pooled standard mean difference between FT angles in patients with or without LDH was 0.31 with (P = 0.04). The pooled odds ratio for FT in patients with LDH was 3.27 with (P = 0.02). Subgroup analysis showed that there is no significant difference in the L3/4, L4/5, and L5S1 subgroups. The pooled standard mean difference between FT angles in patients with or without LDS was 0.54 (P = 0.009).

CONCLUSIONS

FT is significantly associated with LDH and LDS along with various other lumbar and cervical degenerative diseases.

Relationship Between Endplate Defects, Modic Change, Facet Joint Degeneration, and Disc Degeneration of Cervical Spine

Objective

The “disc degeneration precedes facet joint osteoarthritis” hypothesis and multidimensional analysis were actively discussed in lumbar spine. However, in cervical spine degeneration, the multifactorial analyzes of disc degeneration (DD), Modic changes (Mcs), facet degeneration, and endplate degeneration (ED) is still limited. In this cross-sectional study, we aimed to analyze the prevalence and interrelationship of cervical DD parameters.

Methods

We retrospectively recruited 62 patients aged between 60 and 70 years. The disc height, segmental angle, ossified posterior longitudinal ligament (OPLL), ED, facet joint degeneration (FD), uncovertebral joint degeneration (UD), DD, spinal stenosis (SS), Mc, and cord signal change (CS) were evaluated using a previously well-known grading system.

Results

The prevalence of cervical degenerative parameters were DD (grade 1, 1.2%; grade 2, 13.3%; grade 3, 54.8%; grade 4, 19.0%; grade 5, 11.7%), OPLL (26.2%), SS (grade 0, 7.7%; grade 1, 42.3%; grade 2, 26.2%; grade 3, 23.8%), UD (39.1%), ED (normal, 69.0%; focal defect, 9.7%; corner defect, 11.7%; erosion, 6.9%; sclerosis, 2.8%), and FD (normal, 48.8%; narrowing, 27.0%; hypertrophied, 24.2%). The interrelationship of degenerative parameters showed close relation between UD, SS, DD, OPLL, Mc. ED, and CS has partial relation with degenerative finding. FD only has relation with UD, and Mc.

Conclusion

Our results may indicate that FD is a degeneration that occurs independently, rather than as a result of other degenerative factors.

Morphometric analysis of the costal facet of the thoracic vertebrae

Various studies have examined morphometric features of the vertebrae to understand the functional aspects of the spine. Geometric analysis of vertebral zygapophyseal facets has also been related to functional and clinical aspects of the spine, but no quantitative investigation of the costotransverse joint facet is found in the literature. The costal facet geometry may partly determine the mechanical interaction between the rib cage and spine for trunk stabilization during functional tasks and during breathing. Therefore, the present study proposes a method for estimating the 3D geometric features of the costal facets of the first 10 thoracic vertebrae (Th1-Th10). Series of landmarks (95 ± 43) were placed on 258 costal facets from a sample of 14 asymptomatic individuals to determine their 3D location and orientation. The relative location of the costal facet was used to investigate symmetry and asymmetry components of the overall vertebrae shape variation among thoracic levels using 3D geometric morphometric methods. Results showed significant variation in sagittal orientation (inclination angle) between levels with a gradual cephalic orientation in the lower levels. No significant difference was observed on transverse orientation (declination angle). The shape of the costal facet was flatter at Th1 and from Th5 to Th10 and more concave from Th2 to Th4. An average difference of 7° between right and left facet orientation in both sagittal and transverse plane was demonstrated. Asymmetry of costal facet relative location was also detected and significantly influenced by the thoracic level. Nevertheless, location and orientation of the costal facets seem to be independent features of vertebrae morphology.

Identifying the Characteristics of Patients With Cervical Degenerative Disease for Surgical Treatment From 17-Year Real-World Data: Retrospective Study

Background

Real-world data (RWD) play important roles in evaluating treatment effectiveness in clinical research. In recent decades, with the development of more accurate diagnoses and better treatment options, inpatient surgery for cervical degenerative disease (CDD) has become increasingly more common, yet little is known about the variations in patient demographic characteristics associated with surgical treatment.

Objective

This study aimed to identify the characteristics of surgical patients with CDD using RWD collected from electronic medical records.

Methods

This study included 20,288 inpatient surgeries registered from January 1, 2000, to December 31, 2016, among patients aged 18 years or older, and demographic data (eg, age, sex, admission time, surgery type, treatment, discharge diagnosis, and discharge time) were collected at baseline. Regression modeling and time series analysis were conducted to analyze the trend in each variable (total number of inpatient surgeries, mean age at surgery, sex, and average length of stay). A P value <.01 was considered statistically significant. The RWD in this study were collected from the Orthopedic Department at Peking University Third Hospital, and the study was approved by the institutional review board.

Results

Over the last 17 years, the number of inpatient surgeries increased annually by an average of 11.13%, with some fluctuations. In total, 76.4% (15,496/20,288) of the surgeries were performed in patients with CDD aged 41 to 65 years, and there was no significant change in the mean age at surgery. More male patients were observed, and the proportions of male and female patients who underwent surgery were 64.7% (13,126/20,288) and 35.3% (7162/20,288), respectively. However, interestingly, the proportion of surgeries performed among female patients showed an increasing trend (P<.001), leading to a narrowing sex gap. The average length of stay for surgical treatment decreased from 21 days to 6 days and showed a steady decline from 2012 onward.

Conclusions

The RWD showed its capability in supporting clinical research. The mean age at surgery for CDD was consistent in the real-world population, the proportion of female patients increased, and the average length of stay decreased over time. These results may be valuable to guide resource allocation for the early prevention and diagnosis, as well as surgical treatment of CDD.

The relationship between facet tropism and cervical disc herniation

Many studies have demonstrated the association between facet tropism and disc herniation in the lumbar spine. Some of them found that lumbar disc herniation was on the side of the more sagittal facet joint interface. However, little is understood about the association of facet tropism with disc herniation in the cervical spine. As the relationship between the facet orientation and the side of cervical disc herniation (CDH) is unclear, the purpose of this study is to investigate that relationship. Ninety-six patients with single-level CDH (C4-C5, C5-C6 or C6-C7) were included in the CDH group of this study. Another 50 age-matched and gender-matched healthy participants who accepted physical examinations were enrolled as the control group. The cervical facet angles of two sides were measured using axial computed tomography (CT). The intersection angle of the midsagittal line of the vertebra to the facet line represents the facet angle. Facet tropism was defined as the angular difference of 7º between the left and the right sides. Facet tropism angle was recorded as the absolute value of the difference of facet angles between two sides. There were 20 herniations at C4-C5 level, 50 herniations at C5-C6 level and 26 herniations at C6-C7 level. The present study showed that more cases in the CDH group had facet tropism than did those in the control group at C4-C5, C5-C6 and C6-C7 level (p = .021, p = .001, p = .015, respectively). The facet tropism angles in the CDH group were significantly bigger than those in the control group at C4-C5, C5-C6 and C6-C7 level (p = .001, p = .002, p = .028, respectively). In the CDH group, the facet angles on the herniated side were found to be significantly bigger than those on the healthy side at C4-C5, C5-C6 and C6-C7 level (p = .000, p = .000, p = .037, respectively). The findings of this present study suggest that facet tropism is associated with the disc herniation in the cervical spine. We also found that cervical disc herniates towards the side of the bigger facet angle with respect to the sagittal plane. There is a need for future studies to verify the biomechanical impact of facet tropism on CDH.

Analysis of Correlation Between Age and Cervical Facet Joint Degeneration and Modic Changes in Patients with Cervical Spondylotic Myelopathy

Background

Because facet joints move with the disc, changes in vertebral bodies occur simultaneously with progression of degeneration of cervical facet joints. This study investigated age-related differences in cervical facet joint abnormalities and multi-dimensional characteristics of MCs in patients with cervical spondylotic myelopathy.

Material/Methods

Forty-five patients underwent both magnetic resonance imaging (MRI) and computed tomography (CT) of the cervical spine. Axial and sagittal parameter changes from C3 to C7, including facet orientation (FO) and facet tropism (FT), and Modic changes (MCs), were evaluated and documented preoperatively, and we also measured the heights and diameters of MCs and performed correlation analysis and established linear regression models.

Results

The axial facet orientation increased slightly from C3 66.5 (11.4) to C7 89.9 (19). The sagittal facet orientation and facet tropism increased between C3–C4 and C6–C7, but it decreased between C4 to C6. The MCs volume decreased from C3 to C4 and increased from C4 to C7. There was a gradual decrease of FO and FT from C3 to C5 and a gradual increase of these 2 angles from C5 to C7 in all age groups. The lowest values of FO and FT were detected at C5, while the highest values of FO and FT were detected at C7.

Conclusions

Age was negatively correlated with the axial, sagittal, and coronal cervical facet orientation, especially at C4/5 level. The FT with respect to the axial and sagittal plane from C5 to C6 increased with age.

The Impact of Cervical Spinal Muscle Degeneration on Cervical Sagittal Balance and Spinal Degenerative Disorders

STUDY DESIGN

This is a retrospective analysis of kinematic magnetic resonance images (kMRI).

OBJECTIVE

To assess the association of cervical paraspinal muscle with cervical sagittal balance and degenerative spinal disorders.

SUMMARY OF BACKGROUND DATA

Although the effects of spinal disorders and cervical imbalance on patient's symptoms have been well described, the relationship of the cervical muscle quality and volume to cervical imbalance or spinal disorders is not well established.

MATERIALS AND METHODS

In total, 100 kMRI taken in a neutral weight-bearing position were analyzed. The adjusted cross-sectional area ratio (aCSA ratio: the value of muscle CSA divided by the vertebral CSA) and fat infiltration ratio of the transversospinalis muscles at C4 and C7 vertebral levels were measured using axial slice of kMRI. The correlation with cervical balance parameters [Oc-C2 angle, C2-C7 angle, C7-T1 angle, C7 slope, T1 slope, cranial tilt, cervical tilt, thoracic inlet angle (TIA), and neck tilt] and cervical degenerative disorders (disk degeneration, Modic change, and spondylolisthesis) were evaluated.

RESULTS

The aCSA ratio at C4 correlated with C2-C7 angle (r=0.267), C7 slope (r=0.207), T1 slope (r=0.221), disk degeneration at C3-4, C4-5, C5-6 (r=-0.234, -0.313, -0.262) and spondylolisthesis at C3 (anterior: r=-0.206, posterior: r=-0.249). The aCSA ratio at C7 correlated with disk degeneration at C3-4, C4-5, C5-6, C6-7 (r=-0.209, -0.294, -0.239, -0.209). The fat infiltration ratio at C4 correlated with TIA (r=0.306) and neck tilt (r=0.353), likewise the ratio at C7 correlated with TIA (r=0.270) and neck tilt (r=0.405). All correlations above were statistically significant with P<0.05.

CONCLUSIONS

The paraspinal muscle volume showed significant relationship with the cervical balance parameters and disk degeneration. While, paraspinal muscle quality related to the thoracic inlet parameters. Our findings can be an important step to develop the knowledge of the association between cervical muscle and cervical degenerative disorders, as well as the sagittal balance of the cervical spine.

LEVEL OF EVIDENCE

Level III.

Facet Joints of the Spine: Structure–Function Relationships, Problems and Treatments, and the Potential for Regeneration

The zygapophysial joint, a diarthrodial joint commonly referred to as the facet joint, plays a pivotal role in back pain, a condition that has been a leading cause of global disability since 1990. Along with the intervertebral disc, the facet joint supports spinal motion and aids in spinal stability. Highly susceptible to early development of osteoarthritis, the facet is responsible for a significant amount of pain in the low-back, mid-back, and neck regions. Current noninvasive treatments cannot offer long-term pain relief, while invasive treatments can relieve pain but fail to preserve joint functionality. This review presents an overview of the facet in terms of its anatomy, functional properties, problems, and current management strategies. Furthermore, this review introduces the potential for regeneration of the facet and particular engineering strategies that could be employed as a long-term treatment.

Thoracic Inlet Parameters for Degenerative Cervical Spondylolisthesis Imaging Measurement

Background

The aim of this study was to explore the diagnostic value of sagittal measurement of thoracic inlet parameters for degenerative cervical spondylolisthesis (DCS).

Material/Methods

We initially included 65 patients with DCS and the same number of health people as the control group by using cervical radiograph evaluations. We analyzed the x-ray and computer tomographic (CT) data in prone and standing position at the same time. Measurement of cervical sagittal parameters was carried out in a standardized supine position. Multivariate logistic regression analysis was performed to evaluate these parameters as a diagnostic index for DCS.

Results

There were 60 cases enrolled in the DCS group, and 62 cases included in the control group. The T1 slope and thoracic inlet angle (TIA) were significantly greater for the DCS group compared to the control group (24.33±2.85º versus 19.59±2.04º, p=0.00; 76.11±9.82º versus 72.86±7.31º, p=0.03, respectively). We observed no significant difference for the results of the neck tilt (NT), C2–C7 angle in the control and the DSC group (p>0.05). Logistic regression analysis and receiver operating characteristic (ROC) curve revealed that preoperative T1 slope of more than 22.0º showed significantly diagnostic value for the DCS group (p<0.05).

Conclusions

Patients with preoperative sagittal imbalance of thoracic inlet have a statistically significant increased risk of DCS. T1 slope of more than 22.0º showed significantly diagnostic value for the incidence of DCS.

Kinematic evaluation of cervical sagittal balance and thoracic inlet alignment in degenerative cervical spondylolisthesis using kinematic magnetic resonance imaging

BACKGROUND CONTEXT

T1 slope is a novel thoracic parameter used to assess cervical spine sagittal balance. Thoracic index (TI) parameters including T1 slope and cervical sagittal alignment parameters may play an important role in degenerative cervical spondylolisthesis (DCS). Current literature regarding the relationship between TI and cervical sagittal alignment parameters in patients with DCS is limited.

PURPOSE

(1) To evaluate the T1 slope, cervical sagittal alignment, and thoracic inlet parameter in patients with DCS using kinematic magnetic resonance imaging (kMRI), and (2) to find a correlation between the T1 slope, TI, and other cervical sagittal parameters in patients with DCS.

DESIGN/SETTING

Retrospective kMRI study, Level III.

PATIENT SAMPLE

Fifty-two patients with DCS from 1,128 patients from a cervical kMRI database.

OUTCOME MEASURES

T1 slope, C2-C7 angle, sagittal vertical axis C2-C7 (SVA C2-C7), cranial tilt, cervical tilt, neck tilt, and thoracic inlet angle (TIA).

METHODS

Cervical spine kMRIs of 52 patients with DCS (mean age 51.7±standard deviation) were analyzed in neutral, flexion, and extension positions. Patients with DCS were divided into two groups: anterolisthesis (N=33) and retrolisthesis (N=19). Each listhesis group was subclassified into grade 1 (slip 2-3 mm) and grade 2 (slip>3 mm).

RESULTS

Grade 2 retrolisthesis had the largest T1 slope followed by grade 1 retrolisthesis, grade 2 anterolisthesis, and grade 1 anterolisthesis. Significant differences were found between the anterolisthesis and the retrolisthesis groups in the neutral position (p=.025). The flexion position had the largest T1 slope and showed a significant difference with anterolisthesis in the neutral position (p=.041). Sagittal vertical axis C2-C7 showed strong correlation with cranial tilt in all DCS groups and all positions.

CONCLUSIONS

In our study, T1 slope was larger in grade 2 DCS, and the retrolisthesis group had larger T1 slope than the anterolisthesis group. Presence of larger T1 slope was significantly correlated with larger cervical lordosis curvature. Furthermore, cranial tilt was strongly correlated with SVA C2-C7.

The Facet Orientation of the Subaxial Cervical Spine and the Implications for Cervical Movements and Clinical Conditions

STUDY DESIGN

Computed tomography study.

OBJECTIVE

To obtain detailed information on the facet orientation in the subaxial cervical spine and explore the correlation to the cervical movements and relevant clinical conditions.

SUMMARY OF BACKGROUND DATA

Although facet orientation was well studied in the lumbar spine, the literatures on the cervical facet orientation were limited and the descriptions were nonspecific.

METHODS

The computed tomography scans of 100 individuals were reconstructed. For each level from C2/C3 to C6/C7, the horizontal plane, the mid-sagittal plane, the coronal plane, and the two facet planes were established. The normal vectors of the five planes were used for the calculation of the facet orientation and the facet tropism.

RESULTS

The angle of the facet plane with respect to the horizontal plane at the C6/7 level was the largest (left side: 64.34° ± 6.60°, right side: 63.37° ± 6.81°, P >0.05). The angle of the facet plane with respect to the coronal plane decreased from C2/C3 level to C6/C7 level. Regarding the angle of the facet plane with respect to the sagittal plane, for the paired facet joints, three types were found: posteromedially oriented, posterolaterally oriented, and ipsilaterally oriented. All (100%) of the facet joints at the C2/C3 level and 65% at the C3/C4 level were posteromedially oriented. In the lower levels of the cervical spine, the posteromedially oriented facet joints were less common. The facet tropism was common phenomenon in the subaxial cervical spine.

CONCLUSION

This study provided detailed information on the facet orientation in the subaxial cervical spine. The cervical facet orientation correlated well with the spinal movements and related clinical conditions.

LEVEL OF EVIDENCE

3.