Acoustic Neuroma | Chiari Malformation | Arteriovenous Malformation | Brain Tumor | Hydrocephalus | Intracranial Hemorrhage | Trigeminal Neuralgia | Aneurysm Clipping | Craniotomy | Cerebral Aneurysm and Subarachnoid Hemorrhage

Acoustic Neuroma

An acoustic neuroma is a benign tumor of the eighth cranial nerve, the acoustic nerve. The acoustic nerve is involved with the sense of hearing and with control of balance. It is located in the base of the skull near the brainstem. About 2,500 new cases of acoustic neuromas are diagnosed per year. 

The most frequent and earliest symptom of an acoustic neuroma is hearing loss. This is due to pressure of the lesion on the eighth cranial nerve. The hearing loss is on the side of the tumor; the other side is unaffected. The hearing loss often is subtle at first; however, in some cases the loss can be quite rapid. Other symptoms can include tinnitus or ringing in the ear, dizziness and balance difficulty. If the tumor is large it may cause facial numbness or weakness. Rarely, patients may complain of headache. This is also most likely if the tumor is large. 

A neurosurgeon may suspect a patient has an acoustic neuroma in cases of hearing loss in one ear. To confirm a diagnosis, a neurosurgeon will do an MRI. This imaging technique accurately identifies the location and size of the tumor, which is important in determining appropriate treatment. 

Treatment options for acoustic neuromas include observation, which may be appropriate in some cases, surgery or radiation. The physician will go over all possible treatment options with the patient and recommend which is most appropriate.  

Observation may be appropriate when the tumor is small, noted incidentally, or if the patient is medically too unstable from another cause to undergo intervention. Observation will usually involve serial MRI examinations at scheduled points in the future. In some cases where the patient has usable hearing in the affected ear, observation is appropriate to extend the ability to hear from the affected ear. 

Surgical intervention is recommended for total removal of the lesion. This involves a craniotomy where a portion of the skull is removed to allow access to the brain and is then returned to position afterwards. This is also the only approach where the tissue can be examined and a definitive determination made as to its tissue type. The surgery is done with the operating microscope, which aids in identification of surrounding structures. In some cases hearing may be preserved; in many patients, hearing loss is so severe before surgery that it cannot be preserved. The postoperative course involves 24-36 hours in the intensive care unit and about five days in the hospital. 

Stereotactic radiosurgery with the gamma knife and cyberknife is used for patients who do not wish to undergo a craniotomy and for patients who are not medically able to withstand surgery. This is a one-day procedure done while the patient is sedated but awake. The goal of radiosurgery is to halt progression of tumor growth. This occurs over time. Since the tumor is not removed, an absolute determination of the makeup of the tumor cannot be determined. Most patients have the procedure and are discharged home the same day or early the next morning. The gamma knife has been in use at St. Luke’s Medical Center, an affiliate of Midwest Neurosurgical Associates, since 1999. Approximately 50 patients are treated each year. 

For more information, contact the Acoustic Neuroma Association at www.anausa.org.

Chiari Malformation

Chiari (Arnold Chiari) Malformation is a name given to a set of anomalies of the base of the skull and cerebral spine. The brainstem and cerebellum protrude down into the spinal canal through the hole at the base of the skull. This can cause symptoms that vary from irritating to disabling. These symptoms may include pain in the arm, decreased sensation in the arms or hands, coordination difficulties, headache and neck pain, swallowing difficulties and/or hoarsness.

The cause of Arnold Chiari malformation is unknown, but theories relating to increased pressure above the cerebellum causing downward displacement of the cerebellum are most accepted. It may occur from trauma to the skull or simply be present at birth. The condition is diagnosed by magnetic resonance imaging (MRI), which allows evaluation of the cerebellum and other structures. 

Treatment involves surgical decompression of the area to relieve pressure on the cerebellum. This may include removal of a small portion of the skull covering the spine of the neck to provide extra room for the brainstem and cerebellum. In some cases a shunt (or permanent drainage tube) may be necessary to drain accumulations of spinal fluid within the spinal cord.

Arteriovenous Malformation 

Arteriovenous malformation (AVM) is a condition involving a tangle of abnormally connecting arteries and veins. It may occur in the brain, brainstem or spinal cord. The cause is unknown, but an AVM is usually present at birth or shortly thereafter in affected individuals. AVMs of the brain or spinal cord (neurological AVMs) are believed to affect approximately 300,000 Americans, or about 1 percent of the population. They occur in males and females of all racial or ethnic backgrounds at roughly equal rates.  

The blood flowing through the abnormal vessels of an AVM is under high pressure and moves too quickly to provide enough oxygen to the brain. The most common symptom of an AVM is headaches. Other symptoms include hemorrhaging (bleeding), seizures and neurological problems such as paralysis, muscle weakness or loss of speech, vision, coordination or memory. Only about 12% of people with AVMs have symptoms; most people with AVMs do not require treatment. Symptoms are most often noticed in a person’s twenties, thirties or forties. 

AVMs can be diagnosed with an angiogram in which a thin flexible tube is inserted into an artery and guided to the AVM. A contrast dye is then introduced which reveals the AVM on X-ray. Sometimes computed tomograpy (CT or CAT scan) or magnetic resonance imaging (MRI) is used for diagnosis. 

Medications can relieve some AVM symptoms, but definitive treatment involves surgery or endovascular treatment. Conventional surgery involves entering the brain or spinal cord and removing the central part of the AVM. Minimally invasive state-of-the-art techniques are also available, particularly for AVMs deep inside the brain. Embolization, through a neuroendovascular treatment, involves closing off the AVM blood vessels by injecting glue into them or placing coils or tiny balloons there. Stereotactic radiosurgery is a scalpel-free procedure utilizing a gamma knife to focus radiation on the AVM. Over a period of months, the blood vessels of the AVM then degenerate and eventually close. The type of treatment depends upon the size and location of the AVM, surrounding critical structures, and the patient’s general health and well-being.

Brain Tumor 

Brain tumors are divided into many classifications. A distinction is usually made between primary brain tumors, or tumors of the brain itself, and metastatic tumors, or tumors that originate elsewhere in the body and travel through the bloodstream to the brain. Another distinction is made between malignant or cancerous tumors and tumors that are benign. Primary brain tumors may be either benign or malignant. Metastatic tumors are malignant. 

The classification of the tumor is determined after a biopsy. During a biopsy, some or all of the tumor is removed and the cells are examined under a microscope. Definitive treatment of the tumor cannot be started until a final diagnosis is completed after biopsy.  

At the time of the initial biopsy, the surgeon will remove as much of the tumor as is possible without sacrificing function such as speech or movement. This may involve a full craniotomy, or opening of the skull, to allow access to the tumor. In cases where the tumor is adjacent to vital structures, a decision may be made prior to surgery to perform only a biopsy rather than attempting to remove the entire tumor. This is a smaller operation that may or may not involve attaching a headframe and opening only a small hole in the skull to allow for tissue samples to be removed. 

Some brain tumors do not produce symptoms. Other times, symptoms may include headaches, especially at night, seizures or neurological difficulties related to speech, vision, numbness, weakness, balance or walking.  

Meningiomas are tumors of the meninges or coverings of the brain. Typically they are benign. Acoustic neuromas or tumors of the acoustic (hearing) nerve and pituitary tumors are other common benign tumors. They may be treated with surgical resection (removal), radiation or stereotactic radiosurgery with the gamma knife. The type of treatment depends upon the size and location of the tumor, surrounding critical structures, and the patient’s general health and well-being.  

Gliomas are malignant tumors of the brain itself. Gliomas are graded, or divided, into levels based upon their rate of growth and potential for rapid deterioration. The higher the grade, the more aggressive the tumor. Treatments for gliomas depend upon the grade and will typically involve a combination of therapies including surgical resection, chemotherapy and radiation. The rate of survival depends upon the grade of the tumor as well as the individual’s response to therapy.  

The total treatment of brain tumors is a team effort. This involves the neurosurgeon, the medical oncologist, the radiation oncologist, their staffs and the patient and family. New treatments are being developed rapidly and the prognosis for patients with brain tumors is brighter than it ever was in the past. 

For additional information about brain tumors and their treatment, you may wish to contact the American Brain Tumor Association at www.abta.org, or the National Brain Tumor Foundation at www.braintumor.org or the Acoustic Neuroma Association at www.anausa.org.

Hydrocephalus 

Hydrocephalus is a condition caused by excessive accumulation of fluid in the brain. Once known as “water on the brain,” the fluid actually is cerebrospinal fluid, a clear fluid surrounding the brain and spinal cord. An excessive accumulation causes potentially harmful pressure on the tissues of the brain. Hydrocephalus can be present at birth or caused by traumatic injury or diseases such as meningitis and cancer. Symptoms in infants include an unusually large head size, vomiting, sleepiness and seizures. Older children and adults may experience headaches, vomiting, nausea, vision problems, balance and coordination disturbances, urinary incontinence, and personality or cognitive changes. Magnetic resonance imaging (MRI) may help diagnose the condition. Hydrocephalus can be treated with the surgical placement of a shunt system, which diverts the flow of fluid to another part of the body where it can be absorbed as part of the normal circulatory process.

Intracranial Hemorrhage 

Intracranial hemorrhage, also known as intracerebral hemorrhage, is a form of stroke in which a blood vessel in the brain ruptures. Because the blood vessel bursts, blood is cut off from the area of the brain for which it was intended, causing brain damage. In addition, the resulting bleeding and swelling can damage surrounding brain tissue. Intracranial hemorrhage may be caused by an -aneurysm, arteriovenous malformation, trauma or high blood pressure. A subarachnoid hemorrhage is a hemorrhage that occurs between the membranes that cover the brain. 

Symptoms of an intracranial hemorrhage vary, but usually develop without warning. A sudden, severe headache, nausea and vomiting, vision problems, muscle weakness in the limbs and a change in alertness or consciousness are some of the symptoms. Seizures, difficulty breathing and the inability to swallow or speak are other symptoms of intracranial hemorrhage. 

When diagnosing an intracranial hemorrhage, a neurosurgeon may find decreases in brain function and swelling of the optic nerve upon physical examination of the patient. Various blood tests may be conducted to determine the cause and amount of bleeding. Computed tomography (CT or CAT), magnetic resonance imaging (MRI) or angiography (in which dye is injected into an artery and viewed with X-rays) may be performed to diagnose the location and extent of the bleeding. 

An intracranial hemorrhage requires immediate care to reduce brain damage and prevent death. Treatment depends on the cause, location and extent of bleeding. Brain surgery may be necessary to repair blood vessels or remove areas where blood has collected (hematomas). Sometimes less-invasive neuroendovascular treatments can be used instead of open surgery. Medications may be prescribed to reduce swelling in the brain, reduce pain and control seizures that can result from hemorrhaging. Intravenous infusion of medications, fluids and blood products may be necessary.

Trigeminal Neuralgia 

Trigeminal neuralgia (also known as Tic doloroux) is a condition of excruciating facial pain. Often the pain can be triggered by activities such as touching your mouth, talking, eating, brushing your teeth, shaving, a cold wind or even a light breeze. These pains often last only moments, but the pain is so severe as to be incapacitating. About 15,000 new cases are diagnosed annually in the United States. It is caused by vascular compression of the fifth cranial (trigeminal) nerve. It may involve one, two or (rarely) three branches of the nerve. It rarely occurs on both sides of the face. 

Treatment initially involves drugs such as Tegretol, Baclofen or Dilantin. If medical treatment is ineffective or if side effects of the medications are unacceptable, surgical treatment may be considered. The surgical approaches include: 

• Peripheral nerve branch block with phenol alcohol 

• Percutaneous trigeminal rhizotomy with glycerol, balloon or radiofrequency 

• Microvascular decompression 

• Stereotactic radiosurgery with gamma knife 

Peripheral nerve branch block involves an injection into the nerve roots along the side of the head. Rhizotomy involves cutting a nerve root in the cheek. Microvascular decompression is brain surgery to place a sponge-like material between the trigeminal nerve and adjacent blood vessels to alleviate pressure from blood flow. The gamma knife is a scalpel-free method of brain surgery using beams of radiation. For additional information and support for this condition, contact the Trigeminal Neuralgia Association: www.tna-support.org.

Aneurysm Clipping 

Aneurysm clipping is a type of surgery to treat a ballooning (aneurysm) in the wall of a blood vessel in the brain. The procedure is done to prevent the aneurysm from bursting and causing a brain hemorrhage (severe bleeding) which could result in permanent brain damage or death. 

The patient is under general anesthesia (unconscious). An opening is made in the skull (craniotomy) to allow surgeons access to the aneurysm. A surgical microscope is used to view the aneurysm and place a tiny, spring-loaded clip over the aneurysm. Blood flow to the aneurysm is stopped by the clip and the aneurysm collapses, while blood continues to flow through the normal walls of the blood vessel. Hospitalization may last a week. 

Aneurysm clipping is a permanent treatment, but may be replaced in some cases with a less-invasive procedure, aneurysm coiling, a type of neuroendovascular surgery.

Craniotomy 

A craniotomy is a surgical procedure that allows access to the brain and other tissues within the skull to treat various conditions and disorders, such as benign and cancerous brain tumors, cerebral aneurysm, hydrocephalus and Parkinson’s disease. A craniotomy involves removing a section of bone from the skull. At the end of the procedure the bone is put back in place and eventually fuses together with the bones of the skull. A craniectomy is a similar procedure in which a portion of bone is removed from the skull, but not put back in place. For example, the bone may not be replaced under an area of the skull that is covered by muscle, or a tumor may have invaded that section of bone. A prosthetic plate may replace skull bone that is not put back in place. 

A craniotomy is performed by first making an incision in the scalp covering the skull near the tumor or disorder. A series of small burr holes are made in the skull roughly marking the edges of the bone to be removed. The bone “flap” is then created by cutting between the burr holes until it can be removed from the surrounding skull bone. The membranes covering the brain are then cut away to reveal the area of the brain to be treated. After the treatment is completed, the brain membranes are sutured (or replaced and sewn shut), the bone flap is restored to the skull and anchored with wire sutures, plates or screws. Burr holes may be covered with small plates. Finally, the scalp is sewn back together. The patient will be admitted to the intensive care unit and given antibiotics to prevent infection.

Cerebral Aneurysm and Subarachnoid Hemorrhage 

A cerebral or intracranial aneurysm is a dilation or ballooning of an arterial blood vessel in the brain. If an intracranial aneurysm ruptures, it results in a subarachnoid hemorrhage. This bleeding between the thin layers of tissue that cover the brain often causes serious consequences such as death or severe disability. 

The most common symptom of subarachnoid hemorrhage is severe headache. This is frequently associated with nausea, stiff neck and sensitivity to light. 

A computed tomograpy (CT or CAT) scan of the brain is used to diagnose the subarachnoid hemorrhage, and a cerebral angiogram is then done to determine the size, location and status of the aneurysm. During an angiogram, a thin flexible tube (catheter) is inserted into an artery in the upper thigh and guided through the blood system to the head. There, a contrast dye is introduced into the brain, which reveals the extent of the hemorrhage when X-rayed. 

Patients with subarachnoid hemorrhage require treatment for the aneurysm as well as treatment for complications of the hemorrhage such as vasospasm (constricting of a blood vessel which reduces blood flow and increases pressure) and hydrocephalus (fluid build-up in the brain). 

The traditional surgical treatment for cerebral aneurysm is a craniotomy. A portion of the skull is removed to allow access to the brain and is then returned to position afterwards. The surgeon locates the aneurysm and a clip is applied to prevent further flow into the aneurysm. The patient will be in the intensive care unit after surgery and will remain in the hospital for at least a week. 

In some cases the aneurysm is better treated with neuroendovascular therapy. Here microcatheters are placed in the arterial system and coils are delivered into the aneurysm. These coils fill the aneurysm, eliminating blood flow into the aneurysm. The surgeon, based on the type and location of the aneurysm, makes the determination as to whether the aneurysm should be coiled or clipped. 

In some cases, magnetic resonance imaging (MRI) or CAT scan may detect the aneurysm prior to any rupture. The treatment for unruptured aneurysms is much the same as for ruptured aneurysms. However, these patients are generally more stable and the surgical or endovascular procedure may be done electively rather than under emergency conditions.

For more information, visit www.brain-aneurysm.com

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