Spinal Arthritis Diagnostic Imaging Approach Part I

Degenerative Arthritis

• Spinal Arthritis:
• Spondylosis aka Degenerative disease of the spine represents an evolution of changes affecting most mobile spinal segments beginning with:
• Intervertebral disc (IVD) dehydration (desiccation) and degeneration aka Degenerative Disc Disease (DDD) with an abnormal increase in mechanical stress and degeneration of posterior elements affecting 4-mobile synovial articulations ( true osteoarthritis)
• 2-Facets in the L/S & 2-Facets & 2-Uncovertebral joints in the C/S
• Imaging plays a significant role in the diagnosis, grading, and evaluation of neurological complications (e.g., spondylotic myelopathy/radiculopathy)
• X-radiography with AP, Lateral & Oblique spinal views provides Dx and classification of Spondylosis
• MR imaging may help to evaluate the degree of neurological changes associated with degenerative spinal canal and neural foraminal stenosis

• Spinal motion segment:
• 2-adjacent vertebrae
• IVD (fibrocartilage)
• 2-facets (synovial)
• Pathology: loss of disc height increases mechanical stress on mobile elements
• Ligamentous laxity/local instability
• Spinal osteophytes aka spondylophytes & bony facet/uncinate proliferation
• Disc herniation and often disc-osteophyte complex
• Ligamentum flavum “hypertrophy” or thickening due to buckling
• Loss of normal lordosis with or w/o reversal or kyphosis
• Vertebral canal & neural foraminal stenosis

Neutral lateral cervical radiograph: note mild to moderate disc narrowing and spondylophyte formation at C5-6 & C6-C7 (most common levels affected by cervical spondylosis). Straightening or flattening with mild reversal of cervical lordosis. Some mild facet proliferation is noted at the above levels

• On radiographs: evaluate for disc height (mild, moderate or severe) loss
• End-plate sclerosis & spondylophytes; mild, moderate or severe
• Facet and uncinate irregularity, hypertrophy/degeneration; mild, moderate or severe
• Note degenerative instability aka degenerative spondylolisthesis/retrolisthesis
• Normal or lost lordosis vs. degenerative kyphosis
• Key Dx: correlate with a clinical presentation: neck/back pain with or w/o neurological disturbance ( myelopathy vs. radiculopathy or both)

• Uncinate processes undergo degeneration/proliferation resulting in uncovertebral arthrosis
• Early findings present with mild bone proliferation along the cortical margin (white and black arrows) if compared to normal uncinate (orange arrow)
• Later, more extensive bone proliferation extending into and narrowing vertebral canal and neural osseous foramina (IVF’s) may be noted. The latter may contribute to spinal/IVF stenosis and potential neurological changes
• Posterior oblique views may help further

• AP lower cervical (a) and posterior oblique (b) views
• Note mild uncinated process proliferation with neural foraminal narrowing (arrows)
• Typically if less than a third of IVF becomes narrowed, patients may present w/o significant neurological signs

• Lumbar spondylosis is evaluated with AP and lateral views with additional AP L5-S1 spot view to examine lumbosacral junction
• Typical features include disc height loss/degeneration
• Intra-discal gas (vacuum) phenomenon (blue arrow) along with spondylophytes
• Degenerative spondylolisthesis and/or retrolisthesis (green arrow) may follow disc and facet degeneration and can be graded by the Meyerding classification
• In most cases, degenerative spondylolisthesis rarely progresses beyond Grade 2
• Lumbar facet degeneration seen as bone proliferation/sclerosis and IVF narrowing

• MR imaging w/o gad C is an effective modality to evaluate clinical signs of spondylosis & associated neurological complications with pre-surgical evaluation
• Case: 50-y.o Fe with neck pain. Case b-45-y.o.M (top a b images). MRI reveals: loss of disc hydration or desiccation, spondylophytes and disc herniation w/o neurological changes
• (Bottom images) Left: preoperative and right postoperative MRI slices of the patient presented with clinical signs of cervical spondylotic myelopathy. Note disc herniation, ligam flavum hypertrophy and canal stenosis (left)

• Sagittal MRI slice of lumbar DDD manifested with disc desiccation and posterior herniation effacing thecal sac
• Correlating sagittal and axial slices will be more informative to evaluate canal stenosis and potential degree of neurological involvement (above-bottom images)

• Use the following resources to learn more on MRI evaluation and diagnosis of Degenerative Disc Disease:
• https://radiopaedia.org/articles/intervertebral-disc-disease-nomenclature
• https://ac.els-cdn.com/S1529943014004094/1-s2.0-S1529943014004094-main.pdf?_tid=bab686bc-cf70-4479-a243-b6d2b342461c&acdnat=1535573367_98364d2d06b7c967d3e859e785eb6f13

Diffuse Idiopathic Skeletal Hyperostosis (DISH) aka Forestier disease

• Flowing degenerative ossification of ALL
• M/c Thoracic spine. 2nd m/c-cervical spine
• Dx by imaging only. X-radiography is sufficient
• CT w/o contrast helps with Dx of Fx
• Men>women. Pts>60-y.o. Extensive DISH shows 49% association with type 2DM
• Complications: Chalk (carrot) stick Fx. Unstable 3-column Fx requiring surgical fusion

• Sagittal reconstructed CT scan slice in bone window
• Chalk stick Fx at C5-C6 in the patient with DISH and OPLL

Spinal Arthritis