Radiographic evaluation of cervical spondylosis using an elemental grading system in a population-based cohort study of a Japanese mountain village.

Background: Cervical spine radiography is a common screening tool for cervical spondylosis with radiographic features, including osteophytes, disc height narrowing, vertebral sclerosis, and spondylolisthesis. The Kellgren-Lawrence classification is widely used for evaluating musculoskeletal radiographs, including spinal radiographs; however, evaluating the individual radiographic features of spondylosis is challenging with this classification. This study aimed to develop an elemental grading system for evaluating cervical spine radiographs and the extent of cervical spondylosis.

Methods: In total, 320 participants from a typical Japanese mountain village were included in this study. From the lateral cervical spine radiographs from C2/C3 to C6/C7, radiographic features related to cervical spondylosis were separately graded as 0, 1, or 2 according to the severity of degeneration. The sum of the grades of each radiographic feature at each intervertebral level was designated the intervertebral grade. The average grades of each radiographic feature (osteophytes, disc height narrowing, vertebral sclerosis, and spondylolisthesis), intervertebral grade, and Kellgren-Lawrence classification of the whole cervical spine were defined as 'wOP,' 'wDHN,' 'wVS,' 'wSL,' 'wIG' and 'wKL,' respectively.

Results: This elemental grading system showed good inter- and intraobserver reliability, similar to the Kellgren-Lawrence classification. The distribution of grades 1 and 2 in osteophytes, disc height narrowing, and vertebral sclerosis was observed most frequently at the C5/C6 level, followed by the C4/C5 and C6/C7 levels, whereas a significantly higher spondylolisthesis grade than expected was found at C4/C5. Participants with neck pain showed significantly higher wVS (P < 0.05) than those without neck pain, whereas wOP, wDHN, wSL, wIG, and wKL showed no significant differences.

Conclusions: We developed a grading system for radiographic cervical spondylosis with high reliability and a simple design, which will contribute to future epidemiological studies in evaluating the extent of degenerative changes on cervical radiographs.