Prevalence and Clinical Impact of Cervical Facet Joint Degeneration on Degenerative Cervical Myelopathy: a Novel Computed Tomography Classification Study

Prevalence and distribution of cervical facet joint degeneration in patients with cervical spondylotic myelopathy without/with instability and ossification of the posterior longitudinal ligament-a comparative study

OBJECTIVES

To compare the prevalence and distribution characteristics of the grade of cervical facet joint degeneration (FJD) among patients with cervical spondylotic myelopathy without/with instability (CSM/CSMI), and ossification of the posterior longitudinal ligament (OPLL). Furthermore, to compare the differences in sagittal parameters and preoperative clinical symptoms between patients with mild and severe FJD.

METHODS

The study enrolled 253 patients who underwent surgical treatment at our institution (90 CSM, 79 CSMI, 84 OPLL). A 5-grade computed tomography classification was used to assess bilateral cervical facet joint degeneration from C2/3 to C6/7, with higher grades indicating more severe degeneration. Patients in CSM, CSMI, and OPLL groups were divided into two subgroups separately according to the sum of bilateral FJD grades from C2/3 to C6/7: mild group and severe group. The sagittal parameters of the cervical spine on X-ray, as well as the preoperative Japanese Orthopaedic Association (JOA) score and visual analogue scale (VAS) for neck pain, were compared between the subgroups.

RESULTS

The prevalence of grade 1 to 5 FJD in CSM, CSMI, and OPLL patients was: 77.5%, 17.8%, 3.6%, 1.1%, and 0% for CSM; 62.0%, 25.2%, 7.7%, 3.0%, and 2.1% for CSMI; and 72.4%, 24.4%, 2.2%, 0.3%, and 0.7% for OPLL. The grade of FJD at C2-6 was significantly higher in the CSMI group than the CSM and OPLL groups (P < 0.05). The grade of FJD was highest at C4-C5 in CSM and CSMI groups, while it gradually increased from C3-C4 to C6-C7 in the OPLL group. Patients in severe subgroup exhibited pronounced cervical lordosis, T1 slope, cervical sagittal vertical axis (cSVA), and neck pain (P < 0.05).

CONCLUSIONS

The grade of FJD is more severe in patients with CSMI than others. The grade of FJD in CSM and CSMI patients was most severe at C4-C5 level, while OPLL patients had increasingly severe FJD from C3-C7 levels, with maximal degeneration observed at C6-C7. Patients with severe cervical FJD in CSM, CSMI and OPLL groups exhibited pronounced cervical lordosis, increased T1 slope, elevated cSVA, and heightened neck pain.

Lower C2 slope and milder uncovertebral joint degeneration are risk factors for pseudarthrosis after single-level anterior cervical corpectomy and fusion (ACCF): retrospective study of 102 patients with minimum 2-year follow-up

BACKGROUND

Achieving bony fusion after anterior cervical corpectomy and fusion is crucial for restoring spinal stability; however, the risk factors associated with fusion failure, or pseudarthrosis, remain unclear. This study aims to identify risk factors for pseudarthrosis following anterior cervical corpectomy and fusion and evaluate the impact of C2 slope and uncovertebral joint degeneration on this condition.

METHODS

Patients who underwent single-level anterior cervical corpectomy and fusion between May 2015 and April 2022 and had a minimum of 2 years of computed tomography follow-up were retrospectively enrolled. Preoperative demographic, surgical, clinical, and radiographic data were collected. Patients were divided into fusion and pseudarthrosis groups based on fusion status evaluated at the final follow-up computed tomography. After identifying statistically significant variables through intergroup comparisons, multivariate logistic regression analysis was conducted to determine the risk factors for pseudarthrosis.

RESULTS

A total of 102 patients were included in the study, with an average follow-up duration of 3.78 ± 1.70 years. At final follow-up, 37 patients (36.3%) developed pseudarthrosis, while 65 patients (63.7%) achieved fusion. No significant differences were observed in demographic and clinical parameters between the groups. The pseudarthrosis group exhibited significantly greater preoperative C2-7 Cobb angles (p = 0.029), segment range of motion (p < 0.001), lower C2 slope (p < 0.001), and less severe uncovertebral joint degeneration grades (p = 0.001). Multivariate logistic regression analysis revealed that, after adjustment, greater segment range of motion (p = 0.003), lower C2 slope (p = 0.006), and milder uncovertebral joint degeneration grades (p = 0.023) were significant risk factors for pseudarthrosis following single-level anterior cervical corpectomy and fusion. The area under the curve of the regression model was 0.867.

CONCLUSIONS

Lower preoperative C2 slope, greater segment range of motion, and milder uncovertebral joint degeneration grades may be risk factors for pseudarthrosis following anterior cervical corpectomy and fusion. These characteristics should be further considered in surgical planning to identify high-risk patients.

Preoperative three-dimensional simulation and clinical evaluation of in-situ bone harvesting in anterior cervical discectomy and fusion surgery

Background

The supplemental harvesting of in-situ bone obtained from cervical vertebrae as cage-filling material in anterior cervical discectomy and fusion (ACDF) results in a good fusion outcome. This study aimed to further quantitatively evaluate the obtainable bone volume and clinical outcomes of cervical in-situ autogenous bone grafting based on a three-dimensional (3D) preoperative simulation.

Methods

This study included 78 patients who underwent single-level ACDF. Prior to the surgical procedure, a 3D simulated surgery was performed by constructing several cutting planes in the cervical vertebrae based on Mimics software. The volumes of the harvested in-situ bone graft, including the anterior lip, posterior osteophytes, and Luschka's joint volumes, were measured during the simulated surgery. Immediate postoperative computed tomography (CT) scans were performed to evaluate the efficacy of the preoperative planning. During the postoperative follow-up period, the neurological function and cervical fusion state were also evaluated.

Results

The average volume of the cage's bone graft groove was 373.1±74.4 mm3, which was lower than that calculated in the preoperative planning (501.6±179.6 mm3, P<0.001). In 88.5% (69/78) of the simulated surgery cases, the harvested bone met the volume of the cage's bone graft groove, aligning with the intraoperative scenario. Male patients, elderly patients, patients with lower surgical segments, and patients with higher-grade facet joint degeneration had a more sufficient availability of in-situ autologous bone. The mean follow-up time was 18.02±4.9 months. At the final follow-up, the pain and functional status scores of the patients had improved significantly following surgery (P<0.05).

Conclusions

Preoperative planning for ACDF using Mimics software was shown to be both feasible and accurate. The 3D simulated surgery revealed that the majority of patients could supply a sufficient volume of cervical autologous bone for intraoperative grafting. The comprehensive analysis of the in-situ bone harvesting in ACDF provided precise reference data for the clinical implementation.

The Relationship Between Craniocervical Morphology and the Presence and Level of Cervical Facet Joint Degeneration

OBJECTIVE

To investigate the relationship between craniocervical morphology and the presence and level of cervical facet joint degeneration (FJD).

METHODS

A total of 108 consecutive female patients aged 45-55 years who had undergone neck + brain CT angiography were included in this retrospective sectional study. Only patients of a certain age and of the same gender were included in order to eliminate the differences that create a disposition to the development of spinal degeneration. The presence of facet joint (FJ) arthritis (grade ≥2 degeneration in at least one affected facet joint) and the grade of the facet joint degeneration for each patient were recorded. A total of 20 lengths and 3 angles of craniocervical morphology were measured. The differences between the individuals with and without FJ arthritis were investigated with the independent-sample t test, and the relationship between the FJD grade and craniocervical morphology was investigated using the Spearman correlation test.

RESULTS

Individuals with FJ arthritis were found to have longer Grabb-Oakes measurement, shorter FM AP length, lower ADI, lower EOP thickness, higher clivus length, higher crista gall-ATS distance, lower CCA angle, lower distance between the C1 vertebra lateral masses, and higher BAI than those without FJ arthritis ( P ˂ 0.05). Besides, we found that the FJD grade increased as the Grabb-Oakes measurement increased, ADI distance decreased, FM AP length decreased, EOP thickness decreased, clivus length increased, basal angle increased, distance between the C1 vertebra lateral masses decreased, and BAI increased ( P ˂ 0.05).

CONCLUSIONS

Differences in craniocervical morphology are statistically associated with degenerative processes that result in degenerative changes in the facet joint. Therefore, some morphological changes in craniocervical anatomy cause changes in the momentum and distribution of the load on the facet joints, predisposing the patient to facet arthropathy and osteoarthritis.

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.

Spinal column radiological factors associated with increased spinal cord intramedullary signal intensity - A study evaluating aging spinal cord's relation to spinal disc degeneration

PURPOSE

Increased intramedullary signal intensity (IISI) on T2 weighted MRI scan (T2WI) can be a radiological feature of spinal cord degeneration. However, the association of IISI to degeneration of the spinal column that protects the spinal cord remains unclear. The purpose of this study was to determine the prevalence of IISI and analyze the independent relationship between IISI and cervical degenerative parameters on X-ray and magnetic resonance imaging (MRI).

METHODS

A retrospective review of MRI, X-ray, and radiology data (n = 144) adult patients with both cervical MRI and X-ray scans was conducted. A total of 39 (27 %) patients with IISI was identified. The remaining 105 patients without IISI made up the control group.

RESULTS

IISI was most frequent in C6-C7 cervical levels. The likelihood of having IISI was 1.947 (Exp(B) 1.947, 95 %CI [1.004-3.776]) times higher in segmental levels with facet joint degeneration. There was an increased likelihood of IISI within the spinal cord with increasing age (Exp(B) 1.034, 95 %CI [1.008-1.060]), maximum spinal cord compression (MSCC) (Exp(B) 1.038, 95 %CI [1.003-1.075]), rotational angle (Exp(B) 1.082, 95 %CI [1.020-1.148]) and posterior disc herniation width (Exp(B) 1.333, 95 %CI [1.017-1.747]) and decreasing Torg-Pavlov ratio (Exp(B) 0.010, 95 %CI [0.001-0.068]).

CONCLUSION

IISI was independently associated with increased age, facet joint degeneration, MSCC, rotational angle, posterior herniation width and decreasing Torg-Pavlov angle. Radiologicaldegenerative changesassociated with IISI indicates a potential for identifying predictors of age related spinal cord morphological changes in DCM, which may allow for early intervention strategies in the future.

Novel Risk Factors for Cervical Facet Joint Degeneration in the Subaxial Cervical Spine: Correlation with Cervical Sagittal Alignment and Bone Mineral Density

OBJECTIVE

The impact of cervical sagittal alignment on cervical facet joint degeneration (CFD) and the risk factors for CFD in patients with degenerative cervical myelopathy (DCM) were investigated in the current study.

METHODS

A total of 250 surgical patients with DCM were recruited. The clinical data and radiographical characteristics, including CFD, cervical sagittal balance parameters, Hounsfield unit (HU) values, disc degeneration (DD), and modic change, were collected. The detailed correlation between these characteristics and CFD was analyzed. Characteristics, including CFD, were compared among the various cervical alignment types and different CFD groups. Finally, the risk factors for CFD were revealed via logistic regression.

RESULTS

CFD was prevalent in DCM patients. Age, cervical sagittal vertical axis (cSVA), range of motion, T1 slope, thoracic inlet angle, DD, HU value, and modic change correlated with CFD segmentally and globally (P < 0.05). The lordosis and sigmoid types had a significantly higher CFD prevalence (P < 0.05). Furthermore, the average CFD threshold for the severe CFD group was 1.625 (area under the curve, 0.958). Additionally, 167 patients with average CFD <1.625 and 83 patients with CFD of ≥1.625 were classified into the mild CFD group and severe CFD group, respectively. Finally, multivariate analysis was performed, and age, cSVA, HU value, modic change, and DD were determined to be independent risk factors for CFD.

CONCLUSIONS

The load distribution tends to shift to a more shear-like pattern in the sigmoid and kyphosis types and in those with a higher cSVA, thereby promoting CFD. Aging, cervical malalignment, low bone mineral density, DD, and modic change were revealed to result in high risks of CFD.

Surgical tactics of two-segmental cervical degenerative diseases: risk factors retrospective assessment and preoperative planning

Background

Currently, in the specialized literature there are no substantiated clinical and radiological indications for differentiated use of anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) in the treatment of patients with two-segmental cervical degenerative diseases. The objectives of this study were to (I) identify risk factors that were associated with unsatisfactory results of two-level ACDF and one-level ACCF in the treatment of patients with cervical degenerative diseases despite current perioperative management, and (II) develop a clinical and radiological algorithm for personalized surgical tactics.

Methods

We retrospectively identified risk factors for the development of unsatisfactory clinical postoperative results after two-level ACDF (n=81) and one-level ACCF (n=78), operated in the period of 2009-2019 for two-segmental cervical degenerative disease.

Results

Satisfactory clinical results after two-level ACDF were noted in cases with total kyphotic deformity of less than 15°; local kyphotic deformity less than 10˚; the absence of circumferential spondylotic cervical stenosis; the absence of a myelopathic lesion at the level of the vertebral body; absence of migrating intervertebral disk (IVD) hernia more than 1/3 of the vertebral body; T1 slope vertebra less than 15°; IVD degeneration according to Suzuki A. 0-II; facet joint (FJ) degeneration according to Okamoto A. I-III; interbody height (IH) more than 2 mm. Satisfactory clinical results after single-level ACCF were registered in cases with IVD degeneration according to Suzuki A. III; FJ degeneration according to Okamoto A. IV-V; IH 3 mm or less; regardless of the cervical lordosis, the angle of local kyphotic deformity and T1 slope, the presence of circumferential spondylotic cervical stenosis, the localization of the myelopathic lesion and the distance of migration IVD herniation.

Conclusions

Individual planning and differentiated implementation of ACDF and ACCF in patients with two-segmental cervical degenerative disease, taking into account a comprehensive preoperative clinical and radiological assessment, contributes to the effective elimination of existing neurological symptoms, reducing the intensity of neck pain and upper limbs pain, restoring the functional state and quality of patients' lives in the minimum 24 months postoperative period, as well as reducing the number of postoperative complications and reoperations.

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.

Enhanced Intervertebral Disc Repair via Genetically Engineered Mesenchymal Stem Cells with Tetracycline Regulatory System

The therapeutic potential of Mesenchymal stem cells (MSCs) for the treatment of Intervertebral disc (IVD) degeneration can be enhanced by amplifying specific cytokines and proteins. This study aimed to investigate the therapeutic potential of tetracycline-off system-engineered tonsil-derived mesenchymal stem cells (ToMSC-Tetoff-TGFβ1-IGF1-BMP7) for treating intervertebral disc (IVD) degeneration. ToMSCs were isolated from a tonsillectomy patient and genetically modified with four distinct plasmids via CRISPR/Cas9-mediated knock-in gene editing. Transgene expression was confirmed through immunofluorescence, western blots, and an enzyme-linked immunosorbent assay for transforming growth factor beta 1 (TGFβ1) protein secretion, and the effect of MSC-TetOff-TGFβ1-IGF1-BMP7 on disc injury was assessed in a rat model. The ToMSC-Tetoff-TGFβ1-IGF1-BMP7 treatment exhibited superior therapeutic effects compared to ToMSC-TGFβ1, and ToMSC-SDF1α implantation groups, stimulating the regeneration of nucleus pulposus (NP) cells crucial for IVD. The treatment showed potential to restore the structural integrity of the extracellular matrix (ECM) by upregulating key molecules such as aggrecan and type II collagen. It also exhibited anti-inflammatory properties and reduced pain-inducing neuropeptides. ToMSC-Tetoff-TGFβ1-IGF1-BMP7 holds promise as a novel treatment for IVD degeneration. It appears to promote NP cell regeneration, restore ECM structure, suppress inflammation, and reduce pain. However, more research and clinical trials are required to confirm its therapeutic potential.

Assessment of Cervical Myelopathy Risk in Ossification of the Posterior Longitudinal Ligament Patients With Spinal Cord Compression Based on Segmental Dynamic Versus Static Factors

OBJECTIVE

Using segmental dynamic and static factors, we aimed to elucidate the pathogenesis and relationship between ossification of the posterior longitudinal ligament (OPLL) and the severity of cervical myelopathy.

METHODS

Retrospective analysis of 163 OPLL patients' 815 segments. Imaging was used to evaluate each segmental space available for the spinal cord (SAC), OPLL diameter, type, bone space, K-line, the C2-7 Cobb angle, each segmental range of motion (ROM), and total ROM. Magnetic resonance imaging was used to evaluate spinal cord signal intensity. Patients were divided into the myelopathy group (M group) and the without myelopathy group (WM group).

RESULTS

Minimal SAC (p = 0.043), (C2-7) Cobb angle (p = 0.004), total ROM (p = 0.013), and local ROM (p = 0.022) were evaluated as an independent predictor of myelopathy in OPLL. Different from the previous report, the M group had a straighter whole cervical spine (p < 0.001) and poorer cervical mobility (p < 0.001) compared to the WM group. Total ROM was not always a risk factor for myelopathy, as its impact depended on SAC, when SAC > 5 mm, the incidence rate of myelopathy decreased with the increase of total ROM. Lower cervical spine (C5-6, C6-7) showing increased "Bridge-Formation," along with spinal canal stenosis and segmental instability (C2-3, C3-4) in the upper cervical spine, could cause myelopathy in M group (p < 0.05).

CONCLUSION

Cervical myelopathy is linked to the OPLL's narrowest segment and its segmental motion. The hypermobility of the C2-3 and C3-4, contributes significantly to the development of myelopathy in OPLL.

Facet Articular Irregularity Is the Most Relevant Risk Factor for Rapidly Progressive Degenerative Cervical Myelopathy

Objective: Facet articular irregularity is associated with rapidly progressive degenerative cervical myelopathy (DCM). However, its significance compared with other known risk factors remains unknown. Therefore, this retrospective study aimed to clarify the potential impact of facet articular irregularity as a risk factor for rapid DCM progression.Methods: This study included 141 consecutive patients with DCM who underwent surgical treatment at our institution. Clinical variables and radiological findings related to DCM progression were collected. Imaging findings were analyzed at the segmental level of myelopathy in each case. The patients were divided into 2 groups based on the presence or absence of rapid DCM progression, and independent risk factors were determined using logistic regression analyses.Results: Overall, 131 patients with a mean age of 63.9 ± 12.6 years were analyzed; 27 patients (20.6%) were classified into the rapid DCM progression group. The mean age was significantly higher in the rapid progression group than in the slow progression group (72.4 ± 9.6 vs. 61.7 ± 12.4, p < 0.001). According to univariate analysis, facet articular irregularity, dynamic segmental translation (≥ 1.6 mm), upper cervical spine involvement above C4–5, history of cerebrovascular events, preceding minor trauma, local lordotic angle (≥ 4.5°), diabetes, hypertension, ligamentum flavum hypertrophy, and age were independent risk factors. Additionally, multivariate analysis showed that facet articular irregularity was the highest risk factor for rapid DCM progression (p = 0.001).Conclusion: Facet articular irregularity is the most clinically significant finding among the known risk factors in patients with rapid DCM progression.