What are the most common spinal injury complications?

6 Min Read

Close up of an inspirational woman in a wheelchair in the woods

It is thought that 2,500 people in the UK suffer a life-changing spinal cord injury every year and 50,000 are living with a spinal injury. Some of these are from trauma – road traffic and other accidents. Others are the result of illnesses or conditions such as cauda equina syndrome or spinal infections.

The spinal cord is a tube-like structure passing from the brain stem towards the bottom of the spine. It consists of nerves which carry signals between the brain and the rest of the body. Three quarters of the way, the bundle of nerves extends below the spinal cord into the cauda equina, latin for ‘horse’s tail’ (so called because of its appearance). The cord has a protective cover with 3 membranes (meninges). It passes through the spinal canal which itself is protected by the spine, composed of 33 vertebrae. Between the vertebrae are discs which cushion them, protecting them from the pressure generated by activity such as walking and running.

This article looks at some of the most common complications from spinal injuries. Most are fortunately not particularly common. Many of these are related to damage to the nerves within or extending out of the spinal cord.


Syringomyelia is a rare condition in which a fluid-filled cyst or ‘syrinx’ forms within the spinal cord. As it expands over time, it puts pressure on the spinal cord, causing pain, increasing weakness in the arms and legs, numbness and stiffness. Syringomyelia may be acquired – caused by injuries, tumours or inflammation around the cord (including meningitis) – or it may be congenital (ie people are born with it).


The arachnoid is one of the 3 membranes surrounding and protecting the spinal cord. Arachnoiditis is where it swells, causing pain (often described as ‘stinging’ or ‘burning’). It can then form scar tissue so that the nerves of the spinal cord stick together. Arachnoiditis can have a number of different causes: direct injury to the spine, infection and irritation by chemicals (including dye used in some diagnostic tests). Injury or compression of the spinal cord, for instance from degenerate discs or stenosis (narrowing of the spinal column), can cause arachnoiditis. Unfortunately there is no way of curing the condition and the main treatment is to manage pain.


Spasticity is a condition where damage to nerve pathways makes muscles contract giving rise to abnormal tightness in the muscle. It is often found in people with cerebral palsy or multiple sclerosis, who have had strokes or injuries to the brain or spine. It is most common in the legs although it can affect muscles elsewhere.

Cardiovascular complications

Spinal cord injuries may increase the risk of heart disease. Again, this is down to nerves not functioning as they should. Signals from the brain regulate blood pressure and heart rate. By controlling how much blood vessels contract they can raise and lower blood pressure. Disruption to nerves within the spinal cord can affect those signals causing lowering blood pressure and heart rate. Patients with injuries above the sixth thoracic vertebra can develop the particular cardiovascular complication of autonomic dysreflexia.

Autonomic dysreflexia

Autonomic dysreflexia is a condition where disruption to the nerves in the spinal cord interferes with signals to and from the brain. The condition is most common in people with injuries above the sixth thoracic vertebra. A stimulus below the level of spinal injury triggers an overreaction by the autonomous nervous system – the system controlling breathing and heart rate. This causes the sudden, uncontrolled onset of high blood pressure. It can be triggered by relatively minor stimuli such as from a full bladder, blistered skin or sunburn. High blood pressure can cause stroke from haemorrhage, seizure or cardiac arrest. This is a life-threatening condition.

Respiratory complications

Spinal cord injuries can impair the respiratory (breathing) system, particularly where the injury is in the cervical spine (neck) or upper thoracic spine. This is because the nerves are impaired affecting the four groups of muscles controlling the diaphragm. Any loss of diaphragm function reduces the lung’s capacity. This increases the risk of congestion in the lungs and of infection. Respiratory complications are the most common cause of illness and death after a spinal cord injury.

Bladder problems

Spinal cord injuries can disrupt the nerves to the bladder and bowel. This is referred to as ‘neurogenic bladder’. Some people may need to pass urine more frequently, more urgently, leak urine or become incontinent. Others may experience difficulty emptying the bladder. A build-up of urine in the bladder can damage the kidneys.

Bowel dysfunction

A spinal cord injury can also damage the nerves controlling bowel function. The brain cannot properly control how the intestines function. Stools take longer to pass into the large bowel and people suffer constipation. Then when the rectum fills there is then a lack of control, so that people may be incontinent.

Pressure sores

Spinal cord injuries increase the risk of pressure sores. People may have a lack of feeling so that they do not feel pain when skin starts to become damaged. They may also spend more time immobile, sitting or lying too long in one position without moving or turning. They may also find themselves lying on hard objects such as catheter connectors. Pressure sores can lead to infection and in some case to sepsis or amputation.

Neuropathic pain

Around 80% of people with spinal cord injuries experience significant pain. Pain may be due to nerve damage or problems in the muscles, skeleton or joints arising indirectly from their spinal cord injury. Neuropathic pain is often described as burning, stabbing or tingling. It is thought to arise from the brain misinterpreting signals it receives from the injured area.


Deep vein thrombosis (DVT) and pulmonary embolism (PE) are serious complications of spinal cord injury. They are most common in the 6 month period after injury. DVT is a clot the forms in a deep vein, normally in the calf or thigh. The clot can break off and make its way to the lung, where it causes a PE. This can be life threatening. The risk can be reduced by taking anticoagulation – blood thinners – to prevent clots forming.