Facet arthropathy evaluation: CT or MRI?

Automated magnetic resonance imaging-based grading of the lumbar intervertebral disc and facet joints

Background

Degeneration of both intervertebral discs (IVDs) and facet joints in the lumbar spine has been associated with low back pain, but whether and how IVD/joint degeneration contributes to pain remains an open question. Joint degeneration can be identified by pairing T1 and T2 magnetic resonance imaging (MRI) with analysis techniques such as Pfirrmann grades (IVD degeneration) and Fujiwara scores (facet degeneration). However, these grades are subjective, prompting the need to develop an automated technique to enhance inter-rater reliability. This study introduces an automated convolutional neural network (CNN) technique trained on clinical MRI images of IVD and facet joints obtained from public-access Lumbar Spine MRI Dataset. The primary goal of the automated system is to classify health of lumbar discs and facet joints according to Pfirrmann and Fujiwara grading systems and to enhance inter-rater reliability associated with these grading systems.

Methods

Performance of the CNN on both the Pfirrmann and Fujiwara scales was measured by comparing the percent agreement, Pearson's correlation and Fleiss kappa value for results from the classifier to the grades assigned by an expert grader.

Results

The CNN demonstrates comparable performance to human graders for both Pfirrmann and Fujiwara grading systems, but with larger errors in Fujiwara grading. The CNN improves the reliability of the Pfirrmann system, aligning with previous findings for IVD assessment.

Conclusion

The study highlights the potential of using deep learning in classifying the IVD and facet joint health, and due to the high variability in the Fujiwara scoring system, highlights the need for improved imaging and scoring techniques to evaluate facet joint health. All codes required to use the automatic grading routines described herein are available in the Data Repository for University of Minnesota (DRUM).

Evolution of lumbar degenerative spondylolisthesis with key radiographic features

Spondylolisthesis is a common finding in middle-aged and older adults with back pain. The pathophysiology of degenerative spondylolisthesis is a subject of controversy regarding not only its etiology but also the mechanisms of its progression. It is theorized that degeneration of the facets and discs can lead to segmental instability, leading to displacement over time. Kirkaldy-Willis divided degenerative spondylolisthesis into three phases: dysfunction, instability, and finally, restabilization. There is a paucity of literature on the unification of the radiological hallmarks seen in spondylolisthesis within these phases. The radiographic features include (1) facet morphology/arthropathy, (2) facet effusion, (3) facet vacuum, (4) synovial cyst, (5) interspinous ligament bursitis, and (6) vacuum disc as markers of dysfunction, instability, and/or restabilization. We discuss these features, which can be seen on X-ray, CT, and MRI, with the intention of establishing a timeline upon which they present clinically. Spondylolisthesis is initiated as either degeneration of the intervertebral disc or facet joints. Early degeneration can be seen as facet vacuum without considerable arthropathy. As the vertebral segment becomes increasingly dynamic, fluid accumulates within the facet joint space. Further degeneration will lead to the advancement of facet arthropathy, degenerative disc disease, and posterior ligamentous complex pathology. Facet effusion can eventually be replaced with a vacuum in severe facet osteoarthritis. Intervertebral disc vacuum continues to accumulate with further cleft formation and degeneration. Ultimately, autofusion of the vertebra at the facets and endplates can be observed. With this review, we hope to increase awareness of these radiographical markers and their timeline, thus placing them within the framework of the currently accepted model of degenerative spondylolisthesis, to help guide future research and to help refine management guidelines.

Grading Systems of Lumbar Facet Joint Inflammatory Changes on Magnetic Resonance Imaging: A Scoping Review

STUDY DESIGN

A scoping review.

OBJECTIVE

We aimed to identify and characterize grading systems of the inflammatory features of the lumbar facet joints (FJs) noted on magnetic resonance imaging and summarize their reliability.

SUMMARY OF BACKGROUND DATA

Chronic low back pain is one of the most common causes of disability worldwide and is frequently accompanied by FJ osteoarthritis. Inflammatory changes in the lumbar FJs are commonly noted in imaging studies of patients with FJ osteoarthritis and low back pain. Several grading systems for these inflammatory changes have been developed. However, these grading system's features and reliability have yet to be reviewed.

MATERIALS AND METHODS

We performed a literature search of studies reporting grading systems for FJ inflammatory changes published in English or Spanish between 1985 and 2022. We collected data on reported interreader reliability measures of each grading system. Finally, we compared the features of inflammation described by each system.

RESULTS

Six studies met the inclusion criteria and were used in our analysis. Features commonly graded in these systems are the hyperintensity signal noted within the FJ, bone marrow edema, and the extent of the soft-tissue edema surrounding the FJs. We found that the interreader reliability measures ranged from 0.56 to 0.96.

CONCLUSIONS

Only 6 studies have reported methods for documenting inflammation in the FJs. Studies varied in the precise tissues and phenomena included in the grading systems. However, the systems were generally reliable. Future studies should document the reliability of these methods when independent investigators are not involved in developing the classification schemes. Further work might combine one or more of these measures to establish a standard and reliable grading system for inflammatory changes in the FJs, including signal intensity within the joint, bone marrow edema, and soft-tissue inflammation.

Deep learning for automated, interpretable classification of lumbar spinal stenosis and facet arthropathy from axial MRI

OBJECTIVES

To evaluate a deep learning model for automated and interpretable classification of central canal stenosis, neural foraminal stenosis, and facet arthropathy from lumbar spine MRI.

METHODS

T2-weighted axial MRI studies of the lumbar spine acquired between 2008 and 2019 were retrospectively selected (n = 200) and graded for central canal stenosis, neural foraminal stenosis, and facet arthropathy. Studies were partitioned into patient-level train (n = 150), validation (n = 20), and test (n = 30) splits. V-Net models were first trained to segment the dural sac and the intervertebral disk, and localize facet and foramen using geometric rules. Subsequently, Big Transfer (BiT) models were trained for downstream classification tasks. An interpretable model for central canal stenosis was also trained using a decision tree classifier. Evaluation metrics included linearly weighted Cohen's kappa score for multi-grade classification and area under the receiver operator characteristic curve (AUROC) for binarized classification.

RESULTS

Segmentation of the dural sac and intervertebral disk achieved Dice scores of 0.93 and 0.94. Localization of foramen and facet achieved intersection over union of 0.72 and 0.83. Multi-class grading of central canal stenosis achieved a kappa score of 0.54. The interpretable decision tree classifier had a kappa score of 0.80. Pairwise agreement between readers (R1, R2), (R1, R3), and (R2, R3) was 0.86, 0.80, and 0.74. Binary classification of neural foraminal stenosis and facet arthropathy achieved AUROCs of 0.92 and 0.93.

CONCLUSION

Deep learning systems can be performant as well as interpretable for automated evaluation of lumbar spine MRI including classification of central canal stenosis, neural foraminal stenosis, and facet arthropathy.

KEY POINTS

• Interpretable deep-learning systems can be developed for the evaluation of clinical lumbar spine MRI. Multi-grade classification of central canal stenosis with a kappa of 0.80 was comparable to inter-reader agreement scores (0.74, 0.80, 0.86). Binary classification of neural foraminal stenosis and facet arthropathy achieved favorable and accurate AUROCs of 0.92 and 0.93, respectively. • While existing deep-learning systems are opaque, leading to clinical deployment challenges, the proposed system is accurate as well as interpretable, providing valuable information to a radiologist in clinical practice.

A Predictive Clinical-Radiomics Nomogram for Differentiating Tuberculous Spondylitis from Pyogenic Spondylitis Using CT and Clinical Risk Factors

OBJECTIVE

The study aimed to develop and validate a nomogram model with clinical risk factors and radiomic features for differentiating tuberculous spondylitis (TS) from pyogenic spondylitis (PS).

METHODS

A total of 254 patients with TS (n = 141) or PS (n = 113) were randomly divided into training (n = 180) and validation (n = 74) groups. In addition, 43 patients (TS = 22 and PS = 21) were collected to construct a test cohort. t-test analysis, de-redundancy analysis, and minimum absolute shrinkage and selection operator (lasso) algorithm were utilized on the training set to obtain the optimal radiomics features from computed tomography (CT) for constructing the radiomics model and determine the radiomics score (Rad-score). Eight clinical risk predictors were identified to develop the clinical model. Combined with clinical risk predictors and Rad-scores, a nomogram model was constructed using multivariate logistic regression analysis.

RESULTS

A total of 1781 features were extracted, and 12 optimal radiomic features were utilized to construct the radiomic model and determine the Rad-score. The combined clinical radiomics model revealed good discrimination performance in both the training cohort and the validation cohort (AUC = 0.891 and 0.830) and was superior to the clinical (AUC = 0.807 and 0.785) and radiomics (AUC = 0.796 and 0.811) models. The calibration curve and DCA also depicted that the nomogram had better clinical efficacy. The discriminative performance of the model is well validated in the test cohort (AUC=0.877).

CONCLUSION

The clinical radiomic nomogram could serve as a promising predictive tool for differentiating TS from PS, which could be helpful for clinical decision-making.

A Novel Grading System of Destructive Lumbar Spondyloarthropathy Based on Evaluation of the Facet Joints

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To develop and evaluate a new grading system for destructive lumbar spondyloarthropathy (DLSA) by assessing bony destruction of the facet joints; to evaluate interrater reliability; and to determine the association between anteroposterior (AP) dural sac diameter at the lumbar level and the new grading.

SUMMARY OF BACKGROUND DATA

The characteristics of DLSA are unknown, hindering clinical care and research. Imaging to determine the cause of DLSA may positively contribute to patient outcome or well-being by providing prognostic information.

PATIENTS AND METHODS

In the magnetic resonance images (MRIs), we measured an axial midline AP dural sac diameter and evaluated bone destruction caused by amyloidosis at the level of the center of each lumbar disk of the lumbar spine. Two orthopedic surgeons independently evaluated each case at two-month intervals and assigned the grade by rating bone destruction at each lumbar level. Weighted κ and intraclass correlation coefficients for interrater reliability were calculated. In addition, the correlation between the AP diameter of the spinal dural sac at the lumbar level and the new MRI-based DLSA grade was examined.

RESULTS

The sample size of 82 patients was reached by examining records of 118 consecutive patients. The mean (SD) age of the included patients was 65 (7.2) years, and 36 (43.9%) were women. The grading of DLSA showed moderate to good interrater reliability at both assessments (κ, 0.59-0.78). Intraclass correlation coefficient showed substantial to excellent agreement (intraclass correlation coefficient, 0.63-0.86). The AP diameter of the spinal dural sac at the lumbar level showed a significant correlation with the new grading ( P <0.001).

CONCLUSIONS

The new MRI-based grading system for DLSA has good interrater reliability, although the strength of agreement varies somewhat. The new grading system correlates with AP dural sac diameter. Thus, this classification focused on facet erosion, which leads to functional incompetence may be helpful in surgical decision-making.

Quantitative Radiological Characteristics of the Facet Joints in Patients with Lumbar Foraminal Stenosis

Purpose

This study aimed to evaluate the degeneration patterns of the facet joints (FJs) in patients with lumbar foraminal stenosis (LFS) and investigate the correlation between quantitative parameters and FJ osteoarthritis (FJ OA).

Patients and Methods

A total of 171 patients with LFS at the L4/5 level and 146 control patients were enrolled in this study. The severity of FJ OA was graded according to the Weishaupt classification. The FJ orientation, FJ tropism, superior articular process cross-sectional area (SAPA), and FJ area were measured at the L3/4, L4/5, and L5/S1 spinal levels. Associations among the parameters were assessed using Pearson's correlation coefficients. Independent sample t-tests and Pearson's chi-square tests were used for univariate analyses. The association between LFS and the quantitative parameters was also analyzed using multivariate logistic regression models adjusted for age, gender, and body mass index.

Results

Patients with LFS had more sagittal FJ orientation (37.9 vs 45.0, p < 0.001), more FJ tropism (5.6 vs 3.8, p < 0.001), larger SAPA (129.0 vs 97.8, p < 0.001), and less FJ area (21.7 vs 23.3, p = 0.016). Logistic regression analysis showed that LFS was significantly associated with FJ tropism (odds ratio [OR]: 1.153; p = 0.003) and SAPA (OR: 1.113; p < 0.001). The SAPA showed the largest area under the curve (0.908, 95% confidence interval: 0.875-0.942) for the diagnosis of LFS. The optimal cutoff value was 114.75 mm2 with 85.4% sensitivity and 87.0% specificity. Additionally, a significant correlation was observed between FJ OA and SAPA and FJ area at each studied spinal level.

Conclusion

This study confirmed that LFS is significantly associated with FJ hypertrophy and tropism. FJ hypertrophy and joint space narrowing correlated with the severity of FJ OA. These results are helpful in understanding the morphology and pathology of FJs.

Anterior column reconstruction of the lumbar spine in the lateral decubitus position: anatomical and patient-related considerations for ALIF, anterior-to-psoas, and transpsoas LLIF approaches

PURPOSE

Circumferential (AP) lumbar fusion surgery is an effective treatment for degenerative and deformity conditions of the spine. The lateral decubitus position allows for simultaneous access to the anterior and posterior aspects of the spine, enabling instrumentation of both columns without the need for patient repositioning. This paper seeks to outline the anatomical and patient-related considerations in anterior column reconstruction of the lumbar spine from L1-S1 in the lateral decubitus position.

METHODS

We detail the anatomic considerations of the lateral ALIF, transpsoas, and anterior-to-psoas surgical approaches from surgeon experience and comprehensive literature review.

RESULTS

Single-position AP surgery allows simultaneous access to the anterior and posterior column and may combine ALIF, LLIF, and minimally invasive posterior instrumentation techniques from L1-S1 without patient repositioning. Careful history, physical examination, and imaging review optimize safety and efficacy of lateral ALIF or LLIF surgery. An excellent understanding of patient spinal and abdominal anatomy is necessary. Each approach has relative advantages and disadvantages according to the disc level, skeletal, vascular, and psoas anatomy.

CONCLUSIONS

A development of a framework to analyze these factors will result in improved patient outcomes and a reduction in complications for lateral ALIF, transpsoas, and anterior-to-psoas surgeries.

Evaluation of the degenerative lumbar osseous morphology using zero echo time magnetic resonance imaging (ZTE-MRI)

PURPOSE

To determine and compare the performance of zero echo imaging (ZTE) with conventional MRI sequences on lumbar osseous morphology in patients suspected with lumbar degeneration with multi-slice computed tomography (MSCT) as standard reference.

METHODS

22 subjects with concerned lumbar degeneration were recruited. All subjects were scanned with ZTE sequence after routine conventional MR sequences on a 3.0 T system and also received MSCT examination. Image quality was assessed. The quantitative and qualitative parameters of lumbar osseous morphology on MSCT, ZTE and MRI images were evaluated by three musculoskeletal radiologists independently. Inter-reader and inter-modality reliability and the difference between the modalities were calculated.

RESULTS

There was no difference for the osseous parameters between modalities, including axial orientation (p = 0.444), IAD (p = 0.381), lateral recess (p = 0.370), pedicle width (p = 0.067), pedicle height (p = 0.056), and osteophyte grade (p = 0.052). The measurement of the foramina diameter was statistically different between conventional MRI and MSCT (p < 0.05) but not between the MSCT and ZTE (p = 0.660). Conventional MRI was more likely to miss cortical bone abnormalities. ZTE appeared blurrier in cortical bone than MSCT, especially in cases with severe lumbar degeneration. The inter-reader agreement between MSCT and ZTE-MRI was higher than between MSCT and conventional MRI.

CONCLUSIONS

ZTE-MRI could offer more cortical bone details than conventional MRI images and might be a valid alternative to CT for lumbar osseous morphology assessment to some extent.

Reliability of preoperative MRI findings in patients with lumbar spinal stenosis

Background

Magnetic Resonance Imaging (MRI) is an important tool in preoperative evaluation of patients with lumbar spinal stenosis (LSS). Reported reliability of various MRI findings in LSS varies from fair to excellent. There are inconsistencies in the evaluated parameters and the methodology of the studies. The purpose of this study was to evaluate the reliability of the preoperative MRI findings in patients with LSS between musculoskeletal radiologists and orthopaedic spine surgeons, using established evaluation methods and imaging data from a prospective trial.

Methods

Consecutive lumbar MRI examinations of candidates for surgical treatment of LSS from the Norwegian Spinal Stenosis and Degenerative Spondylolisthesis (NORDSTEN) study were independently evaluated by two musculoskeletal radiologists and two orthopaedic spine surgeons. The observers had a range of experience between six and 13 years and rated five categorical parameters (foraminal and central canal stenosis, facet joint osteoarthritis, redundant nerve roots and intraspinal synovial cysts) and one continuous parameter (dural sac cross-sectional area). All parameters were re-rated after 6 weeks by all the observers. Inter- and intraobserver agreement was assessed by Gwet’s agreement coefficient (AC1) for categorical parameters and Intraclass Correlation Coefficient (ICC) for the dural sac cross-sectional area.

Results

MRI examinations of 102 patients (mean age 66 ± 8 years, 53 men) were evaluated. The overall interobserver agreement was substantial or almost perfect for all categorical parameters (AC1 range 0.67 to 0.98), except for facet joint osteoarthritis, where the agreement was moderate (AC1 0.39). For the dural sac cross-sectional area, the overall interobserver agreement was good or excellent (ICC range 0.86 to 0.96). The intraobserver agreement was substantial or almost perfect/ excellent for all parameters (AC1 range 0.63 to 1.0 and ICC range 0.93 to 1.0).

Conclusions

There is high inter- and intraobserver agreement between radiologists and spine surgeons for preoperative MRI findings of LSS. However, the interobserver agreement is not optimal for evaluation of facet joint osteoarthritis.

Trial registration

www.ClinicalTrials.gov identifier: NCT02007083, registered December 2013.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04949-4.

Standardized Classification of Lumbar Spine Degeneration on Magnetic Resonance Imaging Reduces Intra- and Inter-subspecialty Variability

BACKGROUND AND PURPOSE

To determine the efficacy of standardized definitions of degenerative change in reducing variability in interpretation of lumbar spine magnetic resonance imaging within and between groups of subspecialty-trained neuroradiologists (NR) and musculoskeletal radiologists (MSK).

MATERIALS AND METHODS

Six radiologists, three from both NR and MSK groups were trained on a standardized classification system of degenerative change. After an 11-month washout period, they independently re-interpreted fifty exams at the L4-L5 and L5-S1 levels. Responses were converted to a six-point ordinal scale for the assessment of neural foraminal stenosis and spinal canal stenosis (SCS), three-point scale for lateral recess stenosis, and four-point scale for facet osteoarthritis (FO). Intra-subspecialty and inter-subspecialty analysis was performed using the weighted Cohen's kappa with a binary matrix of all reader pairs.

RESULTS

Inter-subspecialty agreement improved from k=0.527 (moderate) to k=0.602 (substantial) for neural foraminal stenosis, from k=0.540 (moderate) to k=0.652 (substantial) for SCS, from k=0.0818 (slight) to k=0.337 (fair) for lateral recess stenosis, and from k=0.176 (slight) to k=0.495 (moderate) for FO. The NR group demonstrated improved intra-subspecialty agreement for the assessment of SCS, from k=0.368 (fair) to k=0.638 (substantial). The MSK group demonstrated improved intra-subspecialty agreement for the assessment of FO, from k=0.134 (slight) to k=0.413 (moderate). Intra-subspecialty agreement was similar for other parameters before and after training.

CONCLUSIONS

As result of the standardized definitions training, the NR and MSK groups each improved in one of the four parameters, while inter-subspecialty variability improved in all four parameters. These definitions may be useful in clinical practice across radiology subspecialties.

Simplified Universal Grading of Lumbar Spine MRI Degenerative Findings: Inter-Reader Agreement of Non-Radiologist Spine Experts

OBJECTIVE

1) To describe a simplified multidisciplinary grading system for the most clinically relevant lumbar spine degenerative changes. 2) To measure the inter-reader variability among non-radiologist spine experts in their use of the classification system for interpretation of a consecutive series of lumbar spine magnetic resonance imaging (MRI) examinations.

METHODS

ATS multidisciplinary and collaborative standardized grading of spinal stenosis, foraminal stenosis, lateral recess stenosis, and facet arthropathy was developed. Our institution's picture archiving and communication system was searched for 50 consecutive patients who underwent non-contrast MRI of the lumbar spine for chronic back pain, radiculopathy, or symptoms of spinal stenosis. Three fellowship-trained spine subspecialists from neurosurgery, orthopedic surgery, and physiatry interpreted the 50 exams using the classification at the L4-L5 and L5-S1 levels. Inter-reader agreement was assessed with Cohen's kappa coefficient.

RESULTS

For spinal stenosis, the readers demonstrated substantial agreement (κ = 0.702). For foraminal stenosis and facet arthropathy, the three readers demonstrated moderate agreement (κ = 0.544, and 0.557, respectively). For lateral recess stenosis, there was fair agreement (κ = 0.323).

CONCLUSIONS

A simplified universal grading system of lumbar spine MRI degenerative findings is newly described. Use of this multidisciplinary grading system in the assessment of clinically relevant degenerative changes revealed moderate to substantial agreement among non-radiologist spine physicians. This standardized grading system could serve as a foundation for interdisciplinary communication.

A diagnostic model for differentiating tuberculous spondylitis from pyogenic spondylitis on computed tomography images

OBJECTIVES

To develop and evaluate a logistics regression diagnostic model based on computer tomography (CT) features to differentiate tuberculous spondylitis (TS) from pyogenic spondylitis (PS).

METHODS

Demographic and clinical features were collected from the Electronic Medical Record System. Data of bony changes seen on CT images were compared between the PS (n = 61) and TS (n = 51) groups using the chi-squared test or t test. Based on features that were identified to be significant, a diagnostic model was developed from a derivation set (two thirds) and evaluated in a validation set (one third). The sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated.

RESULTS

The width of bone formation around the vertebra and sequestrum was greater in the TS group. There were significant differences between the two groups in the horizontal and longitudinal location of erosion and the morphology of axial bone destruction and sagittal residual vertebra. Kyphotic deformity and overlapping vertebrae were more common in the TS group. A diagnostic model that included eight predictors was developed and simplified to include the following six predictors: width of the bone formation surrounding the vertebra, longitudinal location, axial-specific erosive morphology, specific morphology of the residual vertebra, kyphotic deformity, and overlapping vertebrae. The simplified model showed good sensitivity, specificity, and total accuracy (85.59%, 87.80%, and 86.50%, respectively); the AUC was 0.95, indicating good clinical predictive ability.

CONCLUSIONS

A diagnostic model based on bone destruction and formation seen on CT images can facilitate clinical differentiation of TS from PS.

KEY POINTS

• We have developed and validated a simple diagnostic model based on bone destruction and formation observed on CT images that can differentiate tuberculous spondylitis from pyogenic spondylitis. • The model includes six predictors: width of the bone formation surrounding the vertebra, longitudinal location, axial-specific erosive morphology, specific morphology of the residual vertebra, kyphotic deformity, and overlapping vertebrae. • The simplified model has good sensitivity, specificity, and total accuracy with a high AUC, indicating excellent predictive ability.

Facet Arthropathy Following Disc Replacement Versus Rehabilitation: A Prospective Study With 8-Year Follow-Up

STUDY DESIGN

A prospective study of patients originally randomized to total disc replacement (TDR) or multidisciplinary rehabilitation.

OBJECTIVE

To assess the long-term development of facet arthropathy (FA) after TDR versus nonoperative treatment, and to analyze the association between FA and clinical outcome.

SUMMARY OF BACKGROUND DATA

FA may appear or increase following TDR, but the natural course of FA is unclear, and no previous study has evaluated the long-term development of FA following TDR compared with nonoperative treatment.

METHODS

The study included 126 patients with chronic low back pain and degenerative changes in the lumbar intervertebral discs. The patients underwent pretreatment and 8-year follow-up magnetic resonance imaging (MRI) and 8-year follow-up computed tomography (CT) of the lumbar spine. The primary outcome measure was FA development (yes/no) on MRI at index level L4/L5 or L5/S1, defined as increased FA grade value from pretreatment to follow-up according to Weishaupt grading system. Secondary outcomes included the association between FA (on MRI and CT) and Oswestry Disability Index (ODI) or back pain as well as reoperations.

RESULTS

Increased index level FA grade was more frequent after TDR versus nonoperative treatment (36%, 25/69 vs. 2%, 1/57 of patients, P < 0.001), but was not related to change in ODI or back pain. At follow-up, index level FA grades were higher after TDR versus nonoperative treatment (odds ratio 4.0 MRI and 5.9 CT), but were not related to ODI less than or equal to 22. Four patients (6%) treated with TDR and no patients treated nonoperatively were operated for lateral recess stenosis with posterior decompression at the index level during follow-up.

CONCLUSION

Index level FA development was more likely after TDR compared with nonoperative treatment but was not associated with the 8-year clinical outcome. Index level FA may have contributed to reoperations in the TDR group.

LEVEL OF EVIDENCE

2.

Effect of facet-joint degeneration on the in vivo motion of the lower lumbar spine

Objective

This research studied the in vivo motion characteristics of the L3–S1 lumbar spine with facet-joint degeneration during functional activities.

Methods

Thirteen male and 21 female patients with facet-joint degeneration at the L3–S1 spinal region were included in the study. The L3–S1 lumbar segments of all the patients were divided into 3 groups according to the degree of facet-joints degeneration (mild, moderate, or severe). The ranges of motion (ROM) of the vertebrae were analyzed using a combination of computed tomography and dual fluoroscopic imaging techniques. During functional postures, the ROMs were compared between the 3 groups at each spinal level (L3–L4, L4–L5, and L5–S1).

Results

At L3–L4 level, the primary rotations between the mild and moderate groups during left-right twisting activity were significantly different. At L4–L5 level, the primary rotation of the moderate group was significantly higher than the other groups during flexion-extension. During left-right bending activities, a significant difference was observed only between the moderate and severe groups. At L5–S1 level, the rotation of the moderate group was significantly higher than the mild group during left-right bending activity.

Conclusions

Degeneration of the facet joint alters the ROMs of the lumbar spine. As the degree of facet-joint degeneration increased, the ROMs of the lumbar vertebra that had initially increased declined. However, when there was severe facet-joint degeneration, the ROMs of the lumbar spine declined to levels comparative to the moderate group. The relationship between the stability of the lumbar vertebra and the degree of facet-joint degeneration requires further study.

Retrospective Radiographic Study of Degenerative Joint Disease in Cats: Prevalence Based on Orthogonal Radiographs

Feline degenerative joint disease (DJD) has been reported worldwide. Radiographic evidence, including that from single-plane radiographs, has been used for diagnosis in these reports, though orthogonal radiographs are generally required to diagnose DJD. However, more orthogonal radiographs are required for diagnosis. In this study, we investigated how many orthogonal radiographs are necessary to diagnose feline DJD among domestic short-haired cats. We analyzed the data from 101 cats for which the owners requested screening for arthritis. Orthogonal radiographs of appendicular and intervertebral joints were taken from the chest to the caudal side. Radiographs were then reviewed and graded by severity of DJD in each joint. Radiographic evidence of appendicular DJD was detected in 74.26% of 101 cats, of which 40.59% had intervertebral DJD (typically of the lumbosacral joint). Appendicular DJD was most common in elbow joints. Lameness was recognized by an owner of two cats and was diagnosed by a veterinarian in two cats. No obvious pain was detected on palpation in any cats with appendicular osteoarthritis, but lumbosacral DJD was associated with back pain in seven cases. Aging was associated with radiographic evidence of DJD: radiographic evidence of DJD was observed in most older domestic short-haired cats. Most cases without lumbosacral DJD had no obvious symptoms. As the lifespan of cats increases due to better lifestyles, diet, and medical treatment, lumbosacral DJD, which is more likely in older cats, may become an increasingly important clinical problem. In addition, orthogonal radiograph must be taken to make diagnosis for appendicular joint DJD especially hip and stifle joint.