What is Cerebellar Herniation, and What Are the Diagnosis and Treatment Options?

Although the exact cause of cerebellar herniation occurring at any age is not fully understood, significant progress has been made in its treatment.

Cerebellar herniation can manifest with symptoms such as persistent headaches, difficulty swallowing, or dizziness, and is a congenital condition. However, with modern surgical applications, it can now be treated. Prof. Dr. Selçuk Göçmen, a specialist in Neurosurgery at Anadolu Health Center, explains, “Cerebellar herniation is a serious issue that affects both patients and their families. After diagnosis, patients should understand their condition, educate themselves, and work collaboratively with their doctors to manage their healthcare." Prof. Dr. Göçmen provided important information on this topic.

What is Cerebellar Herniation, Its Causes, Diagnosis, and Treatment?

What is Cerebellar Herniation, and What Are Its Causes?
Cerebellar herniation (Arnold-Chiari disease) is a condition where the cerebellar tonsils protrude towards the junction of the brainstem and spinal cord, compressing the nerves that pass through this area. The anatomical structure and shape of the tonsils play a significant role in the diagnosis of cerebellar herniation. Studies highlight that cerebellar herniation occurs in 1-3% of the population and is primarily a congenital issue, meaning it is a developmental anomaly that occurs during pregnancy. Genetic factors (such as a small posterior fossa where the cerebellum is located) and some syndromes (e.g., Klippel-Feil syndrome), bone anomalies, brain tumors or cysts, folic acid deficiency during pregnancy, and exposure to drugs or chemicals can all contribute to cerebellar herniation. This condition can also be seen in children, but it is more common in individuals between the ages of 20-30 and is more prevalent in women. The exact reason it appears at any age remains unclear.

Due to cerebellar herniation, symptoms may arise from the compression of the spinal cord by the cerebellum. Furthermore, this condition can lead to a blockage in the circulation of cerebrospinal fluid (CSF) in the central canal of the spinal cord, increasing pressure and causing symptoms. For example, increased CSF pressure in the brain can result in “Hydrocephalus,” and increased pressure in the spinal cord can lead to “Syringomyelia.” These two conditions may occur alone or in combination with other disorders.

Ehlers-Danlos syndrome, a connective tissue disorder (characterized by overly flexible skin and joints), is considered a subgroup of cerebellar herniation. In 10% of adults with cerebellar herniation, "Pseudotumor Cerebri" is observed. The symptoms include headaches that cause pressure behind the eyes, nausea/vomiting, dizziness, blurred vision, and pain in the neck, shoulders, or back.

How is Cerebellar Herniation Diagnosed?

How is Cerebellar Herniation Treated?

Because the diagnosis of cerebellar herniation can be challenging, approximately half of the symptomatic patients with a confirmed diagnosis undergo surgical treatment. Each patient must be evaluated individually, and surgical expertise plays a crucial role in treatment. For patients with mild symptoms, the "Wait and See" approach is often used. These patients are usually diagnosed accidentally when undergoing MRIs for other reasons (such as head trauma). In some cases, if patients are hesitant to undergo surgery, medical treatment may be used. Lifestyle changes are made, and medications are provided to alleviate pain. In cases where only headaches are present, long-term monitoring and medication may be required before making a surgical decision. If the "Wait and See" approach does not provide relief and the patient wishes to improve their quality of life by addressing their symptoms, surgery becomes the first option.

After an approximately 2-4 hour surgery, patients may need to be observed in the intensive care unit for one night and are usually discharged after 3-4 days in the hospital. Stitch healing typically takes 7-10 days, and recovery times range from 3 weeks to 3 months. In more severe cases or in patients who experience complications after surgery, recovery may take longer, and some issues may remain as sequelae.

Who Undergoes Surgery, and What Surgical Methods Are Used?

Surgical treatment is performed for patients with detected issues such as syringomyelia, hydrocephalus (fluid accumulation in the brain), or worsening compression. In cases with syringomyelia, decompression is typically performed by shaving the posterior fossa and removing the posterior part of the atlas bone to free the connective tissues causing compression. Some surgeons may opt for a patching technique, although this method remains controversial. In suitable cases, the tonsils (the tissues causing compression) may be cauterized and reduced in size. In severe cases of cerebellar herniation, treatments like decompression surgery, microsurgery, or Ventriculoperitoneal Shunt may be necessary.

For patients at risk of cervical instability after decompression (a neurological issue), fusion surgeries may be performed. If there is significant pressure from the front of the spine, decompression surgery may be done through the mouth. Post-surgery, CSF accumulation in the spinal canal may be monitored, and any cystic enlargements typically resolve within 1-2 years as the CSF circulation returns to normal after decompression.

Post-Surgery Recovery and Complications

• After surgery, most patients return to their daily lives, and symptoms tend to decrease significantly, with nearly 80% of patients experiencing improvement. Children typically have better surgical outcomes than adults. However, chronic pain can be a persistent issue for some patients. Multiple surgeries are rarely required for a small number of patients. As research continues, the unknowns about cerebellar herniation are gradually becoming clearer.
• Patients with cerebellar herniation must understand their condition, educate themselves, and collaborate with their doctors to manage their healthcare effectively.

Quick Facts

Cerebellar herniation is a serious condition affecting both patients and their families. It can lead to a variety of symptoms. The real treatment for symptomatic patients is surgery. The goal is to restore the circulation of cerebrospinal fluid (CSF). Hydrocephalus, Syringomyelia, Pseudotumor Cerebri, and Ehlers-Danlos Syndrome are often associated with this condition. After surgery, symptoms improve in 80% of patients with mild symptoms. Surgical results in children are generally better than in adults. Chronic pain can remain as a lasting issue for some patients. Multiple surgeries are rarely required. The unknown aspects of the disease continue to become clearer as research progresses. Patients with cerebellar herniation must understand their condition, educate themselves, and collaborate with doctors in managing their healthcare.

What Are the Types of Cerebellar Herniation?

Type 1: The most common and mild form. Syringomyelia may accompany it. Clinical symptoms typically appear at the age of 20 or later.

Type 2: Appears at birth along with a condition called spina bifida. The baby has a sac in the neck area. Hydrocephalus is commonly observed.

Type 3: Rare. The cerebellum and brain tissue protrude from a space at the back of the head.

Type 4: Very rare and has a fatal course.

Two additional types have been added.

Recent information now includes two more types: Type 0 and Type 1.5. These are milder forms of the condition.

Symptoms of Cerebellar Herniation
The symptoms can vary depending on the degree of pressure and the age group:

• Headaches starting from the neck (which may also be related to hydrocephalus). The pain may intensify with activities that increase intracranial pressure (such as straining, sneezing, coughing, or exercising). Sometimes, nausea and vomiting accompany the headache.
• Dizziness, balance loss (due to cerebellar involvement), walking difficulties.
• Visual problems (involuntary eye movements called nystagmus), hearing issues (tinnitus, hearing loss), difficulty swallowing, speaking and breathing problems, and sleep apnea, which are signs of brainstem involvement.
• Neck and shoulder pain, a sensation similar to an electric shock.
• Weakness and numbness in the arms and legs, lack of sensation to hot and cold, and reduced ability to feel pain, bladder and bowel control issues, all due to syringomyelia.
• Rarely, some adults may experience psychiatric conditions such as self-harm tendencies or suicidal thoughts.
• In infants, signs include tightness in the fontanelles (soft spots on the head), vomiting, difficulty swallowing, developmental delays, frequent irritability, weak crying, epileptic seizures, and visual problems.