Causes of Spinal Cord Compression



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Spinal Cord Compression


L. Klopp

Colorado State University, Fort Collins, CO, USA.


Causes of Spinal Cord Compression


Diseases can affect the spinal cord by parenchymal disruption (intramedullary disease) or by compression of the tissue. Collectively, diseases that cause compression are probably the most common causes of spinal cord dysfunction. Compression can occur from pathology outside the dura (extradural compression) or within the dura (intradural-extramedullary compression). The mechanism of injury, rate of onset, force and kinetic energy of an injury, and the duration of compression all play a role in the severity and progression of clinical signs [1-3]. For example, an acute severe spinal cord compression is more likely to cause acute paraplegia in comparison with a spinal meningioma, which grows slowly and allows functional compensation to occur. However, once the limit of compensation is reached, deterioration of neurologic function can occur rapidly [4]. Clinical signs associated with spinal cord compression depend on the location of the lesion. Clinical signs of spinal cord dysfunction can be found in Chapter 46: Intervertebral Disk Disease. A list of the most common diseases that cause spinal cord compression can be found in Table 42-1. Images of various disease processes that cause spinal cord compression are shown in Fig. 42-1Fig. 42-2Fig. 42-3Fig. 42-4Fig. 42-5Fig. 42-6 and Fig. 42-7.

Table 42-1. Diseases that Cause Spinal Cord Compression

Diseases that Cause Extradural Spinal Cord Compression

Intervertebral Disk Disease
 - Type I
 - Type II
Articular facet joint synovial cysts
Cartilaginous exostosis
Vertebral canal stenosis
 - Caudal cervical vertebral malformation/malarticulation ("Wobbler’s disease")
 - Congenital stenosis
   - Cervical bony stenosis
   - Stenosis associated with hemivertebra (usually thoracic in location)
Neoplasia
 - Sarcomas arising from the vertebra
   - Osteosarcoma
   - Chondrosarcoma
   - Fibrosarcoma
   - Hemangiosarcoma
   - Lymphosarcoma
   - Multiple myeloma
Epidural abscess
Fracture/luxation
 - Congenital
   - Atlantoaxial luxation
 - Traumatic
Hematoma (most commonly associated with intervertebral disk extrusion or trauma)

Diseases that Cause Intradural-extramedullary Spinal Cord Compression

Arachnoid cyst
Arachnoid scarring/fibrosis
Hematoma
Neoplasia
 - Meningioma
 - Nerve root tumor
 - Metastatic neoplasia



Figure 42.1. Extradural compression: T9 chondrosarcoma in an 11-year-old MC bloodhound with acute deterioration of chronic paraparesis. The tumor was removed and the dog’s neurologic function improved daily. A. T2-weighted, sagittal MRI. The tumor has severely and completely compressed the spinal cord. (arrow) B. T2-weighted, transverse MRI. The compressed spinal cord is indicated by the arrow. C. The tumor has been removeden bloc (ventral view of the dorsal lamina) and is surrounded by tumor capsule and normal muscle tissue. The dorsal lamina has been replaced by chrondrosarcoma (black arrow). The tumor margin has been outlined with paint (white arrow). To view click on figure



Figure 42.2. Extradural compression: Low-grade osteosarcoma of the lamina and pedicles of C6 in a 6-year-old, FS Yorkshire terrier. The tumor was removed en bloc and there was no recurrence until the animal was lost to follow-up 2 years later. A. Lateral image of a myelogram. Note the significant dorsal compression of the spinal cord (arrow). B. Computed tomographic scan following myelogram. The tumor has extended into the pedicle on one side (arrow). C. The tumor has been removed en bloc. D. A radiograph taken 1 year postoperatively. To view click on figure



Figure 42.3. Extradural compression: Cartilaginous exostosis of the C4 caudal articular process in an 11-month-old, MC Airedale terrier mix with a 6-month history of progressive tetraparesis. A. Postmyelogram transverse computed tomographic scan. The spinal cord (large arrow) has been compressed to about 25% of its normal diameter by the mass (small arrow). B. The benign tumor was removed, the dog recovered to normal neurologic status and was still normal at 5 years postoperative. To view click on figure



Figure 42.4. Extradural compression: severe stenosis at the level of the C4-5 facet joint in a 7-year-old, FS Basenji with unremitting cervical pain and mild neurologic dysfunction. A computed tomographic scan of the C4-5 spinal level. The spinal cord is triangular-shaped from the compression. A hyperplastic facet joint is indicated by the arrow. This dog had similar stenoses at 3 other levels in her cervical spine (C3-4, C5-6, and C6-7). She had modified medial facetectomies at all levels and recovered to normal function and her pain resolved. To view click on figure



Figure 42.5. Extradural compression: L1-2, type II intervertebral disk extrusion in a 4-year-old, MC German shepherd dog that displayed mild paraparesis and significant thoracolumbar pain. A. T2-weighted, sagittal MRI. The spinal cord is severely compressed by the disk extrusion (arrow). B. T2-weighted, transverse MRI. The spinal cord is compressed to the right and dorsally (black arrow) by the protruding intervertebral disk (white arrow). (IVD = intervertebral disk)To view click on figure



Figure 42.6. Intradural, extramedullary compression: Multiple arachnoid cysts in a 7-year-old, Springer spaniel that had a history of cervical pain and mild tetraparesis after being hit by a car 2 years earlier. At the time of the MRI the dog was poorly ambulatory. The arachnoid cysts were believed to have formed secondary to arachnoiditis from hemorrhage and inflammation. The arachnoid cysts were addressed surgically and she recovered to ambulatory tetraparesis but began to slowly deteriorate over time. Repeat MRI revealed that the cysts were resolved, but that there were progressive parenchymal changes in the spinal cord. A. Preoperative T2-weighted, sagittal MRI. The arrow indicates one arachnoid cyst. Signal hyperintensity within the parenchyma is seen within the circle. This was likely an area of malacia, edema, or early syrinx formation. B. T2-weighted, transverse MRI. The cysts are indicated by the arrows. The spinal cord has taken on an "apple-core" shape due to the intradural compression. To view click on figure



Figure 42.7. Intradural-extramedullary compression: C3 nerve root tumor in a 7-year-old, FS Doberman pinscher that presented with ataxia and cervical pain. Post-myelogram computed tomographic scan with the precontrast image on the left and the postcontrast image on the right. The tumor has caused pressure necrosis of the pedicle and the foramen is widened. (Note the presence of pedicle bone on the left side.) The tumor did not contrast-enhance with the exception of a small blush at the periphery (arrow). To view click on figure



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