Facet joint degeneration of the cervical spine: a computed tomographic analysis of 320 patients.

STUDY DESIGN

Retrospective study.

OBJECTIVE

To determine the frequency of facet arthrosis according to age, sex, and cervical level. In addition, we propose and evaluate a new grading system for cervical facet degeneration.

SUMMARY OF BACKGROUND DATA

Cervical facets can play an important role in symptomatology. However, there is only one computed tomographic grading system for cervical facet joints.

METHODS

From January 2003 to January 2012, 1944 patients underwent computed tomography of the cervical spine in our institution. We randomly selected 40 males and 40 females from each of the following age groups: 40 to 49, 50 to 59, 60 to 69, and 70 to 79, such that we had a total of 320 patients. We then graded the degree of arthrosis of the facet joints from C2 to C7 on the axial, sagittal, or coronal images according to 4 grades. These categories were: grade I, normal; grade II, degenerative changes including joint space narrowing, cyst formation, small osteophytes without joint hypertrophy seen; grade III, facet joint hypertrophy from large osteophytes without fusion; and grade IV, bony fusion of the facet joint. The intra- and interobserver reliabilities for the grading system were calculated using reliability statistics by intraclass correlation.

RESULTS

Facet arthrosis is common with older patients and at C2-C3, C3-C4, and C4-C5. Facet arthrosis was more common on the left side and in males. Greater than grade III facet joint arthrosis was common in patients older than 60 and at C2-C3, C3-C4, and C4-C5. The reliability statistics by intraclass correlation for the grading system was 0.878 for the intraobserver reliability and 0.869 for the interobserver reliability.

CONCLUSION

It seems that upper cervical levels are more likely to degenerate and to have more advanced degrees of degeneration than the lower cervical levels. As expected, age correlates with worsening degeneration. The proposed computed tomographic grading system for cervical facet arthrosis seemed to be reliable.