Syringomyelia

Dimitris Papadopoulos MD Fellow Of Interventional Pain Practice (FIPP)

Updated 13 February, 2011

GENERAL

Syringomyelia is a general term referring to a disorder in which a cyst or a cavity is formed within the spinal cord. This cyst, called a syrinx, may expand and elongate over time, damaging the spinal cord and ultimately leading to paralysis if appropriate measures are not taken. The temporary damage may lead to pain, weakness and stiffness in the back, shoulders and extremities. Syringomyelia may also cause loss of the ability to sense extreme levels of hot and cold, particularly in the hands. Every patient manifests a different combination of symptoms. These symptoms usually vary according to the extent and, often more importantly, to the location of the syrinx within the spinal cord.

The prevalence of syringomyelia is estimated to be 8,4 cases per 100.000 people [1], with symptoms usually starting in early adulthood. Symptoms tend to develop slowly although there may be a sudden onset on the occasion of cough and stretching or due to myelopathy.

DIFFERENTIATION ACCORDING TO AETIOLOGY

In general terms, there are two forms of syringomyelia: congenital and acquired. Additionally, there is one form of the disorder that involves the part of the brain called brainstem. The brainstem controls many of our vital functions, such as respiration and heart rate. When the brainstem is affected by syringomyelia, the condition is called syringobulbia.

CONGENITAL SYRINGOMYELIA

The first major form is related to a brain abnormality called “Chiari malformation”, named after the Austrian Internist  Hans Chiari. This is the most common cause of syringomyelia, in which the anatomic abnormality causes the protrusion of the lower part of the cerebellum from its normal location -in the back of the head-  into the cervical spinal canal. A syrinx may then be formed in the cervical region of the spinal cord. Due to the type of relationship that was thought to exist between the brain and the spinal cord, this type of syringomyelia is often referred to as “communicating syringomyelia”. Symptoms usually start at the age between 25 and 40 years old and may worsen by any aggravation or any activity inducing a sudden backflow of cerebrospinal fluid (CSF). However, some patients with this type of disorder  may have long periods of stabilisation. Others may develop hydrocephalus –in which CSF  accumulates in the brain- or a condition called arachnoiditis, i.e. inflammation of the arachnoid membrane.

It has been observed that in some rare cases syringomyelia is familial.

ACQUIRED SYRINGOMYELIA

The second major form of syringomyelia may occur as a complication from injury, meningitis, haemorrhage, tumor or arachnoiditis. In this case, the fistula or cyst develops in a spinal cord segment that has been impaired due to one of the above stated conditions. The fistula starts expanding. This condition is sometimes referred to as “non-communicating syringomyelia”. Symptoms may be manifested months or even years after the initial injury and include pain, weakness and sensory impairment originating from the site of injury.

The main symptom in post-traumatic syringomyelia (PTS) is pain, which may extend above the site of injury. Symptoms, such as pain, numbness, weakness and loss of temperature sensation, may be limited in one side of the body. Syringomyelia may also have negative effect on perspiration, sexual function and, later, on bladder and bowel control. A typical cause of PTS is a traffic accident injury or a whiplash injury.

The difficulty in diagnosing PTS lies in the fact that symptoms may appear for the first time long after the actual cause that produced the fistula. For example, if there is a car accident, the patient  may experience for the first time PTS symptoms only months later – symptoms such as pain, loss of sensation and reduced skin ability to sense various gradings of hot and cold.

SYMPTOMS

•    The disorder usually occurs in the cervical spine and causes neuropathic pain, paraesthesia, numbness and muscle weakness in upper extremities, either unilaterally or bilaterally. It has to be differentiated from cervical radicular pain resulting from a herniated intervertebral disc.
•    Disturbance of sense of high temperature in upper extremities  may cause even thermal lesions, because patients are not in the position to protect themselves from exposing their hands in hot objects.
•    Should the disorder be accompanied with Arnold Chiari malformation or hydrocephalus, the patient may complain about severe headaches that worsen with cough and strain.
•    The increase of pressure within the spinal cord cyst may affect the long spinal cord nerve fibres that innervate the legs and urinary bladder,  producing spasticity of lower extremities and urinary incontinence.

DIAGNOSIS

Diagnosis is set with MRI. Magnetic Angiography can reveal vascular malformations.

TREATMENT

Α. CONSERVATIVE TREATMENT

•    Drugs from the category of tricyclic antidepressants or antiepileptics or/and their combination
•    Opioids (starting with the milder and moving to the stronger ones) in case the above tricyclics and antiepileptics are not effective enough
•    Diuretics, such as acetazolamide and frusemide, may reduce the production of CSF and decrease the fistula size
•    Oral corticosteroids may reduce CSF production through an uknown mechanism

Β. INTERVENTIONAL TREATMENT

1. MINIMALLY INVASIVE  TREATMENT

•    Spinal Cord Stimulation (SCS)
•    Cortical Brain Stimulation (CBS)
•    Subarachnoid administration of morphine or zikonotide

2. SURGICAL TREATMENT

Although there are various surgical techniques applied for syringomyelia, this condition usually tends to relapse over time.

MEDICAL INFORMATION SOURCES

1. PAIN PRACTICE JOURNAL

2. BONICA”S MANAGEMENT OF PAIN

3. PAIN PHYSICIAN JOURNAL

4. INTERVENTIONAL PAIN MANAGEMENT BOOK

5. NEUROMODULATION JOURNAL