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Frequently Asked Questions (FAQ) About Hypothalamic Hamartomas

 

Note: This information is intended to provide general information about the Hypothalamic Hamartoma (HH) disease process and the treatment available.

This information is not intended to be used for treatment of an emergent condition requiring immediate attention.

What is a craniotomy and is it considered major brain surgery?

Answer: A craniotomy is an opening made into the skull to reach the brain for a variety of conditions, including resection and removal of a lesion. It is a major operation associated with significant risks. A craniotomy should not be performed unless the patient's quality of life is significantly affected by seizures and behavioral concerns. All of the patients whom we have treated have been in critical situations. After treatment they improved with various degrees of success.

How long does the surgery take? What should I expect after surgery and the subsequent days in the hospital?

Answer: Each patient is unique and is treated individually. Various surgical approaches have been identified as treatment options for this disease. The specific approach depends on the size and exact location of the lesion. Open procedures are standard craniotomies and include the transcallosal, orbitozygomatic, and combined eyebrow approaches. These procedures usually take 4 to 6 hours.

An incision is made near the top of the head behind the hairline. The length of the incision depends on the specific approach used. Bone is removed for surgery and replaced at the end of the procedure with titanium plates and screws. The plate and screws should not interfere with metal detectors or future MRI studies. The imaging facility, however, should be advised that these implants are in place before the patient undergoes a scan. The closed procedure, otherwise known as the endoscopic approach, is appropriate if the lesion is small to moderate and located within the third ventricle. This approach reduces the risk of short-term memory loss and other complications associated with the open procedure. So little bone is removed that it is not replaced at the end of the procedure. Typically, the bone regrows within six weeks. This approach not only lessens the surgical time but also reduces the length of the patient's hospital stay to about five days.

The surgeons use a microscope or endoscope (depending on the approach) and a computerized guidance system to navigate between vital structures surrounding the HH lesion at the base of the brain. The hamartoma is a different color from the rest of the brain, and its tissue is slightly softer than brain tissue. The surgeons try to remove the entire lesion. Disconnection of the lesion from the hypothalamus, rather than total removal of the lesion, appears to be the key to reducing or eliminating seizures. Patients seem to follow about the same course of recovery but at different rates. Younger children recover more quickly than older children. They remain sleepy for several days to a week after surgery. Some patients have been able to talk in the recovery room while others may not speak for a week or longer. A breathing tube may remain in place after surgery. The anesthesiologist removes this tube as soon as patients are breathing safely on their own. Once patients are fully awake, they will undergo a neurological assessment and any lingering symptoms will be addressed at that time.

What are the complications and side effects?

Answer: As with any craniotomy, there can be significant complications. The most severe risks are death, hemorrhage, and coma. The most common complications are diabetes insipidus and short-term memory loss. Operating on the hypothalamus is risky because important structures that process short-term memory are nearby. Many patients already have some problems related to short-term memory. Other issues include abnormalities in hormone levels and blood chemistry. Hormone replacement therapy is available to treat such problems.

I have heard that weight gain is a complication of this surgery. What should I expect?

Answer: Most patients gain some weight the first few months after surgery, but this insatiable appetite usually subsides after a few weeks or at most a few months. Frequent, small, balanced meals throughout the day are recommended.

Can you guarantee that the patient will be seizure free after surgery?

Answer: There are absolutely no guarantees. Each patient's progress is different after surgery. However, most of our patients have been seizure free or significantly improved after treatment.

Does age affect outcomes after surgery?

Answer: In general, younger children have recovered quickly while recovery in older patients tends to take longer. The problems associated with HH appear to be progressive. Patients do not seem to respond to medication. They may have difficulties with behavior, including emotional outbursts, and in some cases, rage attacks associated with violent behavior. Usually the frequency of seizures decreases right away, but the behavioral problems may require additional therapy in the patient's local area.

Will the patient be asleep for the MRI before surgery?

Answer: If the patient requires more than light sedation to tolerate the MRI test performed before surgery, arrangements will be made to have the neuroanesthesiologist anesthetize him/her.

Should we obtain a new MRI before we contact your team for a current view of the lesion?

Answer: A hamartoma is considered a lesion, not a tumor, and it does not grow independently of the brain. The quality of the MRI is the most important concern. The type of MRI necessary to evaluate this lesion is a noncontrasted 1.5-Tesla scan although many patients have undergone a 3-Tesla scan. A skilled radiologist is of greater importance than obtaining a stronger MRI scan.

What happens if the patient has a vagal nerve stimulator in place before surgery? Does it need to be addressed?

Answer: If the patient has a vagal nerve stimulator, it will be turned off before all radiographic studies (MRI) and surgeries. The stimulator can interfere with the test results of the MRI, and the facility providing treatment should be informed of its existence. After surgical treatment, the stimulator may be turned back on at the discretion of the team neurologist.

Should anti-epileptic medications be discontinued before surgery?

Answer: Depakote is the only medication that has been identified as interfering with platelet formation and may increase bleeding during surgery. The patient should be tapered off this medication at least a week before surgery. This issue can be managed by the patient's local physician before coming to Barrow Neurological Institute at Phoenix Children's Hospital for surgery.

Will the patient remain on medication for seizure activity after surgery? Who will manage the seizures?

Answer: Our neurologist will handle seizure medicines while the patient is at Barrow at Phoenix Children's. Once the patient returns home, the local neurologist will take the lead role in the management of these medications. Our recommendations are to continue on medication for about a year after surgery. The tapering off process can begin at the discretion of the patient's local neurologist.

Will the patient need to take any other medications after leaving the hospital?

Answer: The primary medications the patient will require are the seizure medicines. A few patients have needed steroids for a short time after surgery. The patient will be tested thoroughly for hormone problems after surgery and may require hormone replacement medication. Some patients may need to take vasopressin, the hormone that allows the body to concentrate urine. This medication is a nasal spray. Therapy must be individualized, but typically a need for additional medications is not expected.

How long will we have to stay in Phoenix?

Answer: We expect you to stay in Arizona about 2 weeks after surgery. The first 5 to 7 days are spent in the hospital; the remaining time is spent outside the hospital. Follow-up appointments with a neurologist, an endocrinologist, and a neuropsychologist will be recommended in your local area. All patients have a final consultation with Dr. Rekate before leaving Phoenix.

What will you need from us in the future for follow-up care?

Answer: About six weeks after surgery we ask for an EEG, MRI, and hormone testing to be completed. The patient's local neurologist, pediatrician, or endocrinologist usually orders these tests. Barrow at Phoenix Children's neurologists are available for consultation with the patient's local neurologist for continuity of care. Our team physicians provide recommendations for follow-up care; however, the local physicians will manage the patient's care after returning home. About a year after the surgery, a follow-up visit in Phoenix is ideal, but not essential.

Have any patients undergone Gamma Knife treatment before surgery? If so, are there age restrictions for this treatment?

Answer: Gamma Knife radiosurgery is a good option; however, it takes 6 to 36 months for the benefits to be seen. It is noninvasive and there is no pain or sensation from the treatment with the exception of discomfort from frame placement. Patients who have improved after Gamma Knife treatment received a dose of 17-18 gray (Gy) to the edge of the hamartoma.

The bottom portion of the hamartoma is near the optic nerves. Damage to this area can cause loss of vision to various degrees. To minimize potential loss of vision, the radiation dose must be low. Therefore, most centers are limiting their dose to the entire hamartoma to 12 Gy. Response rates to this dosage are low. Based on our work, the critical region to treat, whether with surgery or Gamma Knife, is the top and sides of the hamartoma. These areas are important for the control of seizures and improvement of behavior. Therefore we treat the critical portion of the hamartoma with an effective dose while limiting the dose to the bottom of the hamartoma to reduce the risk to the optic nerves. If the patient fails to respond enough in a year, surgery can still be performed. Of the patients whom we have treated by surgery, several had undergone previous Gamma Knife therapy at the lower dose without success.

How does this disease affect personality and cognition of individuals?

Answer: Hypothalamic hamartomas can affect cognitive and personality functions in different ways, depending on the age of the individual and how long the tumor has influenced the normal development of the nervous system. Typically, intelligence, problem solving-abilities, and emotional and motivational behavior can be impaired.

Why should the patient have neuropsychological testing done?

Answer: By understanding the nature of the individual's neuropsychological condition, family, teachers, and patients are in a better position to understand why these individuals are having adjustment problems and what strategies may help to manage their problems.

What type of research are you conducting concerning hypothalamic hamartoma lesions?

Answer: We are pursuing both clinical and basic research concerning hypothalamic hamartomas. Research efforts include genetic mapping, understanding the underlying electrophysiology, defining the neuropharmacology of hypothalamic hamartomas, and understanding neurobehavioral difficulties. Our primary goal is to coordinate the research efforts to expedite the delivery of discoveries in the laboratory to the bedside as rapidly as possible.

Contact Us

For more information, please contact Maggie Bobrowitz, RN at (602) 933-0686 or mbobrowitz@phoenixchildrens.com.

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