Spinal cord herniation

Our experience at Inselspital shows that dural defects are located at the level of the disc space. In some cases, a herniated disc is also revealed during surgery, which is located directly in front of the dural defect and could also be a possible cause *. Constant pressure can cause the dura to perforate and the spinal cord to protrude.

This pathomechanism has similarities to that seen in spontaneous intracranial hypotension (SIH), also called  cerebrospinal fluid leak). In this case, a defect in the anterior dura results in a continuous loss of cerebrospinal fluid (CSF). This defect is most commonly caused by a calcified micro spur – similar to a herniated disc. Patients complain of severe position-dependent headaches as a result of the CSF loss. The medical profession refers to this as orthostatic headache. It is not clear why some patients develop a cerebrospinal fluid leak with typical headaches and other, rare cases, develop spinal cord herniation. At Inselspital, we pay special attention to this condition.

Spinal cord herniation does not have specific symptoms, but it does have characteristic symptoms. Symptoms usually develop insidiously. These include:

• Sensory and gait disorders
• Muscle weakness
• Increased reflexes
• Vegetative conditions such as bladder and fecal incontinence

Typically, Brown-Séquard syndrome also occurs. This is a neurological syndrome caused by hemiplegic spinal cord damage affecting motor and sensory pathways. This is explained by the crossing of the nerve structures at the level of the spinal cord and the brain stem. On the damaged side of the spinal cord, there is a weakness of voluntary motor function and a deep and delicate sensibility. On the opposite side of the body, there are insensations to touch, temperature, and pain. This is why patients with Brown-Séquard syndrome perceive the water as differently warm on the two sides of the body when showering. The syndrome is variable and rarely occurs in its full expression.

Spinal cord herniation and the damage it causes to the spinal cord are best visualized using magnetic resonance imaging (MRI). Spinal cord herniation must be distinguished from a dorsal arachnoid cyst. In this clinical picture, a cyst consisting of the thin meningeal layer arachnoid presses from behind against the spinal cord and displaces it forward in the direction of the spinal column. On imaging, this arachnoid cyst can easily be mistaken for spinal cord herniation. However, a definitive diagnosis is only possible during surgery.

Computed tomography (CT) complementary with contrast medium in the nerve fluid space (CT myelography) can provide additional information about constrictions in the spinal canal, such as in arachnoid cysts or an active CSF leak in spinal cord herniation.

In addition to imaging procedures, electrophysiologist examinations (sensory and motor evoked potentials) are also performed in some cases. These can be used to quantify the extent of spinal cord damage.

The severity of the neurological disorders determines whether and when treatment is required. If no or only very mild neurological disorders are present, progress controls at short intervals are initially sufficient.

In most cases, however, more serious neurological disorders are present. As these continue to increase over time, surgery with microsurgical repositioning of the spinal cord is necessary to prevent further progression of the disease.

As a general rule, neurological disorders that are already present will not always be reversed by surgery. Therefore, the goal of surgery is to prevent further damage and to maintain the current neurological status. For precisely this reason, surgery should be performed at an early stage. An improvement of neurological deficits may occur after surgery, but always remains to be seen.

After the operation, our patients are observed overnight in the neurosurgical monitoring ward. Back on the ward, mobilization takes place on the first day after the procedure under the guidance of our physiotherapy team. There are no restrictions in the mobility or stability of the spine. After only a few days, the patient can be discharged. Depending on the severity of the neurological disorders, there is the possibility of special neurological rehabilitation or discharge home.