Cervical Bony Fusion
Julia Crim, MD
DIFFERENTIAL DIAGNOSIS
Common
Abnormalities of Segmentation
Failure of Vertebral Formation
Partial Vertebral Duplication
Klippel-Feil Spectrum
Vertebral Segmentation Failure
Juvenile Idiopathic Arthritis
DISH
Post-Traumatic Deformity
Spondyloarthropathy, Seronegative
OPLL
Post-Operative Change, Normal
Less Common
Osteomyelitis, Pyogenic
Osteomyelitis, Granulomatous
ESSENTIAL INFORMATION
Helpful Clues for Common Diagnoses
Fusion occurring congenitally or in childhood
Vertebral bodies small in anteroposterior dimension relative to adjacent segments
Juvenile idiopathic arthritis: Associated with arthritis elsewhere
May see cervical instability
Involves vertebral bodies and facet joints
Congenital fusion: May be isolated abnormality or multiple levels
May involve vertebral body, facet joints or both
Known as Klippel-Feil spectrum
May be associated with Sprengel deformity
Often see scoliosis or kyphosis
Fusion due to seronegative spondyloarthropathy
Normal size of vertebral bodies
Intervertebral discs and facet joints fused
Sacroiliac joints always involved with erosions often progressing to ankylosis
Thin syndesmophytes in ankylosing spondylitis cause “bamboo spine” appearance
Flowing ossification along paraspinous ligaments seen in psoriatic and reactive arthritis
Fusion due to DISH
Flowing ossification along paraspinous ligaments
Patients usually older than 50 years
Sacroiliac joints usually normal but rarely appear fused due to enthesophytes
Surgical fusion
Older surgeries often without hardware
Helpful Clues for Less Common Diagnoses
Fusion due to osteomyelitis
Rare in cervical spine
Vertebral body fusion usually does not affect facet joints
Loss of vertebral body height, loss of definition of endplates
Single level in pyogenic, often multiple in granulomatous
Often develop kyphosis
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