A thoracic syrinx is a fluid-filled cavity or cyst that develops in the thoracic region of the spinal cord, resulting in a central core syndrome. Patients with this type of syrinx may experience motor weakness, stiffness and sensory disturbances in the trunk and legs. Some patients are asymptomatic.
While rare, half of syrinxes occur in those with congenital abnormalities in the craniocervical junction, brain or spinal cord that worsen in adolescence or early adulthood. Previous spinal trauma or spinal tumors are also predisposing factors. With treatment, such as surgical decompression or management of underlying causes, long-term prognosis is good.
The overall condition, known as syringomyelia, can worsen rapidly or slowly progress, and it is slightly more common in males. Most sufferers are between the ages of 20 and 40, with 8.4 in 100,000 in the general population affected. The majority of cases are associated with Chiari malformation, a congenital brain abnormality.
In infants and young children, the term syringomyelia is often used interchangeably with hydromyelia, a widening of the central canal of the spinal cord. In these young people, skeletal abnormalities, such as scoliosis, may be the only noticeable symptom. In some adults, loss of bladder control and twitching occur.