What is Cord Myelomalacia
Cord myelomalacia is a pathological softening and necrosis of spinal cord tissue resulting from ischemia, compression, or direct injury, representing irreversible damage to the spinal cord parenchyma. 1
Pathophysiology and Imaging Characteristics
Myelomalacia represents the end result of spinal cord injury through various mechanisms including:
- Chronic compression from degenerative disease, tumors, or vascular malformations causing progressive ischemic damage 1
- Acute ischemic injury from vascular insufficiency or hemorrhagic infarction 2, 3
- Direct trauma leading to hemorrhagic infarction of the spinal cord 4
The condition evolves through distinct stages that can be identified on MRI 2:
- Early stage: High T2 signal intensity involving the full width of the affected cord, representing edema and early necrosis 2
- Intermediate stage: Cystic necrosis of central gray matter becomes prominent on T2-weighted images 2
- Late stage: Central cystic degeneration, syrinx formation, and cord atrophy dominate the imaging appearance 2
Clinical Significance and Prognosis
The imaging changes in the spinal cord due to myelomalacia and gliosis are best discerned by MRI, making it the diagnostic modality of choice. 1
Myelomalacia carries significant prognostic implications:
- Early stage myelomalacia may be reversible if the underlying compression or ischemia is promptly addressed, with some patients showing improvement on follow-up imaging 2
- Intermediate and late stage disease is typically irreversible, with follow-up studies showing either no change or progression despite intervention 2
- Intramedullary cord signal changes on MRI in patients with spondylotic myelopathy represent prognostic factors for neurosurgical outcome 1
Common Etiologies
The most frequent causes include:
- Spondylotic myelopathy from chronic degenerative compression, most commonly affecting the cervical spine 1
- Vascular malformations causing chronic ischemia through "spinal steal" phenomenon 3
- Extradural compression from arachnoid cysts, tumors, or epidural masses leading to secondary cord softening 5
- Acute hemorrhagic infarction following intervertebral disc extrusion or fibrocartilaginous embolism 4
Critical Clinical Pitfall
A common pitfall is assuming all cord signal abnormality represents reversible edema rather than established myelomalacia. The distinction is crucial because myelomalacia indicates permanent tissue damage with limited recovery potential, fundamentally altering surgical expectations and patient counseling. 2