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Grading system for articular surface degeneration of zygapophysial (Z) joints following induced segmental hypomobility in the rat
Author(s) -
Cramer Gregory D.,
Henderson Charles N.R.,
Pocius Judith D.,
Grieve Thomas J.,
Daley Clover
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.649.8
Subject(s) - medicine , grading (engineering) , articular surface , anatomy , grading scale , kappa , nuclear medicine , orthodontics , biomedical engineering , surgery , mathematics , biology , geometry , ecology
Articular surface degeneration (ASD) of the Z joint cephalad articular facets (CAFs) is characterized by roughening, pitting, and remodeling. These changes have been previously found in hypomobile Z joints of rats. Our objective was to refine the method of grading ASD for use in large scale studies. Left and right L4‐S1 CAFs of 6 randomly selected spines (45 CAFs) of control and experimental rats were assessed. The experimental animals had undergone 8 weeks of fixation, using an established, IACUC approved, rat model, in which 3 contiguous segments (L4, L5, L6) were fixed with a specially engineered, surgically implanted, vertebral fixation device. Using a decision tree developed to score overall CAF degeneration, the CAFs were graded under dissection microscopy by 2 observers (blinded to each other and to their own initial scores) to determine: number of regions and size of remodeling; number, location, and depth of pits; and severity and size of roughening. The observers scored the spines on 2 occasions separated by at least 7 days. Weighted kappa showed substantial intra‐observer (k=0.77, SE 0.1) and inter‐observer agreement (first measurement, k=0.72, SE 0.14; second measurement k=0.71, SE 0.14), indicating that the grading system can be used in future studies assessing ASD of CAFs. Support: NIH/NCCAM (Grant #s 1R21 AT00784 and U19 AT002006).