Clival tumors are rare, usually slow-growing tumors that arise in the clivus, an area of bone near the junction of the skull and spine. As they develop, clival tumors can cause a variety of neurological symptoms such as headaches, facial paralysis, problems with coordination and weakness. Depending on circumstances, these unusual tumors can be treated with standard or endoscopic surgical procedures, radiation therapies, or a combination of these, to remove or reduce the tumor and prevent symptoms.
What Are Clival Tumors?
The clivus is a sloping section of bone at the base of the skull – an area that’s surrounded by vital structures including the brainstem, cranial nerves, and important arteries, such as the internal carotid arteries. Clival tumors may be benign and generally remain localized, or malignant, with the potential to spread to other areas of the body. In either case, they have the possibility of growing, invading and damaging surrounding tissues and structures in the brain. Clival tumors include two different types: chordomas and chondrosarcomas.
Clival chordomas arise from remnants of the notochord, an embryonic structure involved in the development of the spinal cord. Normally, the notochord becomes part of the vertebrae as the spine fully develops, but in some cases, additional notochord cells become enclosed by bone and form chordomas, which can continue to grow and affect surrounding brain tissues and functions.
Chondrosarcomas are even rarer than chordomas. These malignant clival tumors arise in the skull’s cartilage, which hardens and is replaced by bone over time. Like chordomas, chondrosarcomas can invade nearby brain structures and can recur after treatment, but they can also spread to other parts of the body.
Symptoms of Clival Tumors
Because clival tumors occur at the base of the skull, they can cause a variety of symptoms, depending on the brain structures that are affected by the tumor’s size and location. These symptoms can include:
- Facial paralysis, pain, or numbness
- Changes or loss of sensations such as taste, smell, or touch
- Problems with coordination and balance
- Double vision
- Changes in speech
- Difficulty swallowing
- Dizziness or vertigo
Clival tumors are usually diagnosed when symptoms appear, although some can be found during testing for other conditions. Diagnosis involves a neurological examination and imaging with MRI or CT scans. A biopsy of the tumor may also be performed.
Clival Tumor Treatment Options
The most effective clival tumor treatment (for both types) is complete surgical resection, or removal, of the tumor, or the removal of as much of it as safely possible. Surgery on the skull base area can be challenging, given the many vital systems and small space in this area, but new technologies are creating more options for neurosurgeons to achieve the most optimal results.
Depending on individual circumstances including the size and location of the tumor and a patient’s age and overall health condition, treatments for both chordomas and chondrosarcomas can include “standard’ surgery with craniotomy, transsphenoidal endoscopic surgery, and radiotherapy.
Extended bifrontal craniotomy is an open surgical approach that involves removing a portion of the skull in order to directly access the tumor at the clivus and remove it. Once the procedure is complete, the skull portion is replaced and secured with titanium plates and screws. In some cases, a less invasive type of craniotomy called an eyebrow or keyhole craniotomy might be performed, which involves a smaller incision in the eyebrow or behind the ear to access tumors in the skull base or front of the brain.
Clival tumors can also be removed or reduced with transsphenoidal endoscopic surgery, a relatively new procedure that allows neurosurgeons to access the tumor using special instruments inserted into the nasal passage without the need for incisions on the skin. In this procedure, the membranes at the back of the nasal passage and the sphenoid bone are opened so that the tumor, or as much of it as possible, can be removed. Because endoscopic procedures are less invasive than standard surgeries, patients recover more quickly and face a lower risk of complications.
Clival tumors are also treated with radiotherapy. Gamma Knife Radiosurgery or proton beam radiotherapy delivers highly targeted radiation directly to the tumor site, so that surrounding healthy tissues are not affected by the treatment. Radiotherapy is non-invasive and has minimal side effects, and may be used alone when surgery is not an option, or as part of a surgical treatment plan.
Recovering From Clival Tumor Treatment
The journey to recovery from treatment for a clival tumor depends on many factors including health, age, and the treatment approach. Recovery from extended bifrontal craniotomy can involve a hospital stay of up to seven days. During recovery at home, which may take four to six weeks, activities such as exercise, driving and returning to work can be gradually increased until they return to normal levels.
Recovery from eyebrow or keyhole craniotomy and transsphenoidal endoscopy can take significantly less time because these procedures are less invasive and cause less trauma. After these procedures, patients typically spend a day or two in the hospital and take two to three weeks to recover at home.
After treatment for either type of a clival tumor, periodic follow-ups with MRI or CT scanning are typically needed, since these tumors can recur and, in some cases, spread to other areas of the body.
Clival tumors affect about one person in a million, including children and adults of all ages. Once a clival tumor is diagnosed, neurosurgeons can work with patients and their families to create a treatment plan that can relieve symptoms and restore your quality of life.