Introduction

• Rare congenital abnormality. Seen more often in the English Bulldog and the Beagle.
• Cause: failure of halves of dorsal spinous processes to fuse.
• May be concurrent with myelodysplasia, abnormal position of central grey matter, anomalies of dorsal and ventral horns.
• Signs: noticed when puppy begins to walk; pelvic limb ataxia and paresis, fecal and urinary incontinence, dimpling of skin over site of defect.
• Treatment: surgical repair in some cases.
• Prognosis: poor to guarded if severe neurological signs. Death is uncommon unless abnormality in cervical area.

Pathogenesis

Etiology

• Hereditary in Bulldogs?.

Predisposing factors

• Animals with associated vertebral defects may be at an increased risk.
• This is most often seen in Bulldogs.

Pathophysiology

• Failure of the vertebral arch to form dorsal to the spinal cord:
  • If many adjacent vertebrae are affected this is termedrachischisis.
  • If the skin and subcutaneous tissues cover the vertebral defect this is termedspina bifida occulta.
  • This defect may also be associated with abnormal formation of the spinal cord due to faulty development of neuronal and supporting cells or abnormalities in migration of differentiating cells.
• In some instances, the meninges and spinal cord may protrude through the vertebral defect.

• Failure of halves of dorsal spinous processes (usually lumbar) to fuse → protrusion of spinal meninges or spinal cord → additional associated spinal anomalies → failure of spinal reflexes to establish → variably impaired neurological function → variable degree of spinal disability.

Diagnosis

Treatment

Prevention

Outcomes