Grading Osteoarthritic Changes of the Zygapophyseal Joints from Radiographs: A Reliability Study

The Relationship of Radiographic Parameters and Morphological Changes at Various Stages of Degeneration of the Lumbar Facet Joints: Cadaver Study

STUDY DESIGN

Cadaveric specimens.

OBJECTIVE

To perform a pathomorphological analysis of the degree of facet joint (FJ) degeneration utilizing fresh cadaveric models and correlating these structural changes with imaging findings.

METHODS

L1-L5 FSU including all tissue between the anterior longitudinal ligament to the posterior spinal structures were obtained on 28 patients at a mean of 5.7 hours post-mortem. The samples were fixed in an agar medium and CT and MRI were performed. The level of FJ degeneration was identified based on prior classifications Osteoarthritis Research Society International (OARSI), as was the facet angle and tropism. Pathomorphological assessment including articular cartilage cell density was performed according to prior established methodology.

RESULTS

Radiographically, a direct association was identified between FJ degeneration and patient age. Facet angle and tropism did not significantly vary by patient age. Pathomorphologically, there was a decrease in the cellular density of articular cartilage with increasing patient age. Similarly, there was a significant direct correlation between radiographic degree of degenerative changes in FJs with the age of cadavers and the degree of degeneration of FJs according to the morphological classification of OARSI, as well as a significant inverse correlation with cell density.

CONCLUSION

A comprehensive assessment of various signs of FJ degeneration using cadaveric material has established that, based on radiographic imaging, it is possible to assess the microstructural state of FJ, including at an early stage of the disease. This data may be useful for surgeons in guiding therapeutic strategies based on individual biometric parameters of the FJ.

Reliability of Human Lumbar Facet Joint Degeneration Severity Assessed by Magnetic Resonance Imaging

OBJECTIVE

The purpose of this study was to determine the reliability of the assessment of lumbar facet joint degeneration severity by analyzing degeneration subscales using magnetic resonance imaging (MRI) in human participants.

METHODS

The reliability of articular cartilage degeneration, subchondral bone sclerosis, and osteophyte formation subscales of lumbar facet joint degeneration severity was assessed in MRI images from n = 10 human participants. Each scale was applied to n = 20 lumbar facet joints (L4/5 level). Three examiners were trained. A first assessment of MRI images was provided by the examiners followed by a second assessment 30 days later. Intraobserver and interobserver reliability were determined using percent agreement, the weighted kappa coefficient κ_w for paired comparisons, and the overall weighted kappa κ_o. The minimum threshold for reliability was set at moderate levels of agreement, κ_w > 0.40, based upon previous recommendations.

RESULTS

The articular cartilage subscale had acceptable intraobserver (κ_o = 0.51) and interobserver (κ_o = 0.41) reliability. Scales for subchondral bone sclerosis (intraobserver κ_o = 0.28; interobserver κ_o = 0.10) and osteophyte formation (intraobserver κ_o = 0.26; interobserver κ_o = 0.20) did not achieve acceptable reliability.

CONCLUSION

Of the 3 subcategories of lumbar facet joint degeneration, only articular cartilage degeneration demonstrated acceptable reliability. Subscales of lumbar facet joint degeneration should be considered independently for reliability before combining subscales for a global degeneration score. Owing to the inherent difficulty of assessing lumbar facet joint degeneration, the use of multiple examiners independently assessing degeneration with reliable scales and then coming to a consensus score upon any disagreements is recommended for future clinical studies.

Facet joint hypertrophy is a misnomer: A retrospective study

One of the major causes of lumbar spinal canal stenosis (LSCS) has been considered facet joint hypertrophy (FJH). However, a previous study asserted that "FJH" is a misnomer because common facet joints are no smaller than degenerative facet joints; however, this hypothesis has not been effectively demonstrated. Therefore, in order to verify that FJH is a misnomer in patients with LSCS, we devised new morphological parameters that we called facet joint thickness (FJT) and facet joint cross-sectional area (FJA).We collected FJT and FJA data from 114 patients with LSCS. A total of 86 control subjects underwent lumbar magnetic resonance imaging (MRI) as part of routine medical examinations, and axial T2-weighted MRI images were obtained from all participants. We measured FJT by drawing a line along the facet area and then measuring the narrowest point at L4-L5. We measured FJA as the whole cross-sectional area of the facet joint at the stenotic L4-L5 level.The average FJT was 1.60 ± 0.36 mm in the control group and 1.11 ± 0.32 mm in the LSCS group. The average FJA was 14.46 ± 5.17 mm in the control group and 9.31 ± 3.47 mm in the LSCS group. Patients with LSCS had significantly lower FJTs (P < .001) and FJAs (P < .001).FJH, a misnomer, should be renamed facet joint area narrowing. Using this terminology would eliminate confusion in descriptions of the facet joint.

A Feasibility Study to Assess Vibration and Sound From Zygapophyseal Joints During Motion Before and After Spinal Manipulation

OBJECTIVE

This feasibility study used novel accelerometry (vibration) and microphone (sound) methods to assess crepitus originating from the lumbar spine before and after side-posture spinal manipulative therapy (SMT).

METHODS

This study included 5 healthy and 5 low back pain (LBP) participants. Nine accelerometers and 1 specialized directional microphone were applied to the lumbar region, allowing assessment of crepitus. Each participant underwent full lumbar ranges of motion (ROM), bilateral lumbar SMT, and repeated full ROM. After full ROMs the participants received side-posture lumbar SMT on both sides by a licensed doctor of chiropractic. Accelerometer and microphone recordings were made during all pre- and post-SMT ROMs. Primary outcome was a descriptive report of crepitus prevalence (average number of crepitus events/participant). Participants were also divided into 3 age groups for comparisons (18-25, 26-45, and 46-65 years).

RESULTS

Overall, crepitus prevalence decreased pre-post SMT (average pre = 1.4 crepitus/participant vs post = 0.9). Prevalence progressively increased from the youngest to oldest age groups (pre-SMT = 0.0, 1.67, and 2.0, respectively; and post-SMT = 0.5, 0.83, and 1.5). Prevalence was higher in LBP participants compared with healthy (pre-SMT-LBP = 2.0, vs pre-SMT-healthy = 0.8; post-SMT-LBP = 1.0 vs post-SMT-healthy = 0.8), even though healthy participants were older than LBP participants (40.8 years vs 27.8 years); accounting for age: pre-SMT-LBP = 2.0 vs pre-SMT-healthy = 0.0; post-SMT-LBP = 1.0 vs post-SMT-healthy = 0.3.

CONCLUSIONS

Our findings indicated that a larger study is feasible. Other findings included that crepitus prevalence increased with age, was higher in participants with LBP than in healthy participants, and overall decreased after SMT. This study indicated that crepitus assessment using accelerometers has the potential of being an outcome measure or biomarker for assessing spinal joint (facet/zygapophyseal joint) function during movement and the effects of LBP treatments (eg, SMT) on zygapophyseal joint function.