Arthritis of the Spine - Spinal Imaging and Image Analysis - page 35

Fig. 2 Plain lateral radiographs of a normal cervical spine (a) and of a patient with cervical
spondylosis (b). Marginal osteophytes are denoted by arrowheads

Table 1 Kellgren Lawrence
grading system: osteoarthritis
is divided into ve grades as
follows [ 8 ]

Grade 0 None

Grade 1 Doubtful

Grade 2 Minimal

Grade 3 Moderate

Grade 4 Severe

fibrotic tissue. With aging, the disk undergoes three phases of degenerative changes
[ 10 ]. In phase I, or the dysfunctional phase, microtrauma from repetitive use causes
small tears and fibrosis, associated with pain. Meanwhile, the

nucleus pulposus loses water content. MRI study often reveals disk bulging without
herniation and tears in the annulus. In phase II, or the unstable phase, more tears
occur and lead to disk disruption, resorption, and loss of the disk space. Local
in

fissures in the annulus

ammation may follow if the herniated disk compresses the spinal nerve root.
Cartilage degeneration and malalignment can develop in the facet joints. Clinically,
patients often present with spine instability and symptoms related to nerve irritation.
Phase III is the stabilization phase. With disk resorption and disk space narrowing,
mechanical stress leads to

fl

fibrosis of the disk and degenerative changes at the

vertebral endplates.
The prevalence of degenerative disk disease is dif cult to estimate. In a MRI

study in 239 asymptomatic individuals with a mean age of 39 years, degenerative
cervical disk disease progressed in 81 % of the study subjects over 10 years [ 11 ].