Pedicle Abnormality

Bryson Borg, MD

DIFFERENTIAL DIAGNOSIS

Common

Congenitally Short Pedicles
Stress Reaction
Trauma
Thinning/Remodeling from Intraspinal or Transforaminal Mass
- Schwannoma
- Neurofibroma
- Perineural Root Sleeve Cyst
- Arachnoid Cyst
- Dural Dysplasia
- Meningocele, Lateral
- Ependymoma
Destructive Tumor
- Metastases, Lytic Osseous
- Aneurysmal Bone Cyst

Less Common

Sclerotic/Bone-Forming Tumor
- Metastases, Blastic Osseous
- Fibrous Dysplasia
- Osteoid Osteoma
- Osteoblastoma
- Osteosarcoma
Osteomyelitis, Granulomatous
Achondroplasia
Congenitally Absent or Hypoplastic Pedicle

ESSENTIAL INFORMATION

Helpful Clues for Common Diagnoses

Congenitally Short Pedicles
- Predominately lower lumbar spine
- Decreased AP dimension of spinal canal and neural foramina
Stress Reaction
- Abnormal biomechanical loading across neural arch, associated with fractures of the pars and pedicle, and degenerative facet disease
- Sclerosis (CT) or T2/STIR hyperintensity (MR) ± visible pedicle or pars fracture
Thinning/Remodeling from Intraspinal or Transforaminal Mass
- Implies chronic mass effect/slow growth
- Cortical margin should be intact on thin-slice bone algorithm CT
Metastases
- Often multiple
- Thin-slice bone algorithm CT useful to differentiate bony destruction from benign bony remodeling
- Purely lytic: Renal, thyroid
- Purely sclerotic: Prostate, carcinoid, bladder
- Mixed sclerotic &/or lytic: Lung, breast

Helpful Clues for Less Common Diagnoses

Osteomyelitis, Granulomatous
- Bony destruction
- Epidural/paraspinal abscesses with irregular marginal enhancement

Image Gallery

Axial NECT shows a typical case of short lumbar pedicles resulting in congenital spinal stenosis with the characteristic trefoil spinal canal cross section.

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