Clinical history An 11 year old female poodle had spinal pain in the TL region for 5-6 weeks that was somewhat responsive to steroid therapy - suddenly the clinical signs worsened, the dog became lame in the hind limbs, and she demonstrated a Schiff-Sherrington syndrome - she continued to have deep pain sensation in the limbs - radiographs were made of the thorax prior to further diagnostic studies Thoracic radiographs - what is your diagnosis? Midthoracic spine (loss of detail because of enlargement) Radiographic changes The changes in the thoracic spine are minimal, but specific for a compression fracture of T6.
- The body of T6 is shortened
- The end plates are identified but are less dense than those in adjacent segments
- The body of T6 is less dense than adjacent segments
- The adjacent disc spaces are of normal width
In this patient there is
- No malalignment of segments
- No bony fragmentation
- No reactive new bone
Differential diagnosis for a shortened vertebral body Compression fracture
- Secondary to trauma
- Secondary to primary bone tumor
- Secondary to metastatic tumor
- Secondary to hematogenous spondylitis
- Secondary to perivertebral foreign body spondylitis
Congenital hemivertebra or “butterfly” segment Myelography was performed using a cisternal injection site Radiographic changes from myelogram following cisternal injection Dorsal contrast column thins and terminates at T5-6 Ventral contrast column terminates at T6 Lesion appears to be an obstructive extradural mass Radiographic diagnosis The pathologic fracture fails to show any bony fragmentation or periosteal new bone or end plate destruction - these tend to exclude trauma or inflammatory disease which stimulate a bony response. The collapse of the segment with bony destruction in the body plus the extradural mass within the spinal canal suggests either primary or metastatic bone tumor. Clinical course A hemilaminectomy was performed A spinal canal mass that compressed the spinal cord was identified arising from the body of T6 The histopathology of the mass was an adenocarcinoma - the primary tumor site was not identified Comment - The Schiff-Sherrington syndrome is an uncommon neurological syndrome It is an extensor hypertonia of the thoracic limbs and paraplegia resulting from acute, severe, compressive lesions of the thoracolumbar spinal cord that remove the inhibitory effects of neurons in the lumbar spinal cord - if seen in dogs, it is usually caused by trauma or a herniated intervertebral disk. The pathologic fracture in this patient must have been acute and resulted in severe cord compression or there was an acute hemorrhagic episode creating the mass effect.
