Disorders That we Treat
 Brain Tumors and Other Brain Disorders:
 Malignant Brain Tumor and Brain Metastases
Metastases to the brain from a primary tumor that is outside the central nervous system (CNS) are more common than primary tumors of the brain. The most common primary tumors that metastasize to the brain are lung, breast, melanoma, and kidney.
There are several advantages for Gamma Knife treatment for malignant brain and brain metastases including:
- No scarring – minimally invasive treatment : Gamma Knife is a minimally invasive form of treatment for brain tumors. Inpatient surgeries and lengthy hospitalizations are not necessary. Outside of the small incision needed for placement of the frame, there is virtually no scarring.
- Few side effects : Because of the minimally invasive form of treatment, Gamma Knife patients experience few side effects. Patients undergoing Gamma Knife treatments are awake and alert throughout the entire procedure. General anesthesia is not necessary and most patients go home the same day as their procedure. Gamma Knife treatment is pain free and silent. Patients report little discomfort.
- Treatment for multiple lesions and metastases : given the minimally invasive nature of treatment, the Gamma Knife is able to treatment more than one metastatic lesion. Multiple tumors, or, lesions are difficult to safely remove surgically. However, the Gamma Knife can be programmed to treat multiple lesions in one treatment episode.
As with all radiation treatments, the Gamma Knife treats metastases by altering the formation of the tumor. Exposure to radiation changes the molecular structure and cellular DNA of brain tumor and/or metastasis. After the exposure to the Gamma Knife radiation treatments, the tumors or metastasis began to dissipate and withdraw.
Benign Tumor – Meningioma
Meningiomas arise from the arachnoid "cap" cells that line the inner "dura" (fibrous covering of the brain) and may arise anywhere these cells are located. Meningiomas can invade the bone or muscle, but such invasion is not a sign of malignancy. Meningiomas can grow through the holes (foramina) at the base of the skull and grow outside the skull. As meningiomas grow, they compress the normal brain.
Similar to other disorders, the Gamma Knife is often an advantageous treatment for meningioma. Meningioma benign tumors can be located in inaccessible locations of the brain that may be too risky for surgical resection. Additionally, Gamma Knife treatment could be provided post surgery should the meningioma could not be completely resected surgically.
Acoustic Neuroma (vestibular schwannoma):
Acoustic neuroma is a benign, usually slow-growing tumor that develops from the balance and hearing nerves supplying the inner ear. The tumor comes from an overproduction of Schwann cells--the cells that normally wrap around nerve fibers like onion skin to help support and insulate nerves. As the vestibular schwannoma grows, it presses against the hearing and balance nerves, usually causing unilateral (one-sided) or asymmetric hearing loss, tinnitus (ringing in the ear), and dizziness/loss of balance.As the tumor grows, it can interfere with the face sensation nerve (the trigeminal nerve), causing facial numbness. Vestibular schwannomas can also press on the facial nerve (for the muscles of the face) causing facial weakness or paralysis on the side of the tumor. If the tumor becomes large, it will eventually press against nearby brain structures (such as the brainstem and the cerebellum), becoming life-threatening.
Gamma Knife treatment offers effective treatment but takes longer to work when compared to surgery. The risks of Gamma Knife treatment are also less than for surgery, and this is the primary advantage of this approach. Gamma Knife treatments can be given either in a single session. For single session Gamma Knife treatment, the frame is "bolted" to the head, a scan is taken and the radiation is given in one large "shot.
Vascular Disorders:
Arteriovenious Malformations (AVM):
A grouping of abnormal blood vessels located in the brain. This group of abnormal blood vessels is characterized by a high blood flow enlarging the vessels. This enlarge vessels may result in subsequent enlarged venous drainage. The main risk associated with AVM is hemorrhaging and bleeding within the brain.
The Gamma Knife radiation treatment targets the Nidus, or the center of the large grouping of abnormal blood vessels. The effects of the Gamma Knife treatment on the AVM and Nidus are not immediate. Similar to treatment of brain metastases and benign tumors, the radiation treatment emitted from the Gamma Knife source results in the DNA molecular structure to change and over time dissipate.
Gamma Knife treatment is particularly effective in treating smaller AVM's that are located in eloquent deep structures of the brain that are difficult to reach, or too risky to resect surgically. Surgical resections of AVM's that are difficult to reach surgically and/or are located near sensitive structures of the brain are associated with high morbidity rates and bleeding. The availability of the Gamma Knife to treat these difficult to reach AVM's has been one of the more significant advancements in the field of vascular surgery.
Cavernoma:
Cavernous malformations are dilated blood vessels that are characterized by multiple distended “caverns” of blood that flow very slowly. The blood filled vascular spaces are surrounded by blood vessel walls that do not have enough smooth muscle and stretchable material (elastin), so they are not strong and get distended. Cavernous malformations can be located anywhere in the body, including the liver, rectum, kidney, eyes, nerves, spinal cord and brain. Brain and spinal cord (cerebral) malformations will be focused on here, as they have the potential for serious symptoms
Pain and Functioning Disorders
Trigeminal Neuralgia:
Trigeminal neuralgia (TN) is a disorder of the fifth cranial (trigeminal) nerve that causes episodes of intense, stabbing, electric shock-like pain in the areas of the face where the branches of the nerve are distributed - lips, eyes, nose, scalp, forehead, upper jaw, and lower jaw. A less common form of the disorder called "Atypical Trigeminal Neuralgia" may cause less intense, constant, dull burning or aching pain, sometimes with occasional electric shock-like stabs. Both forms of the disorder most often affect one side of the face, but some patients experience pain at different times on both sides. Onset of symptoms occurs most often after age 50, but cases are known in children and even infants.
Gamma Knife treatment has in recent years become the treatment of choice for people unresponsive to medical therapy for trigeminal neuralgia. Recent advances in imaging and increased experience with its use, have underscored the importance of gamma knife as a treatment option and good pain relief has been achieved with its use.
The exact mechanism of pain relief is unknown. It is thought to be a two step process. Patients report an immediate decrease in the intensity of the pain even if the attacks still occur. This is thought to be the result of an immediate interruption of ephaptic transmission. Several weeks later there is complete cessation of the attacks. This is probably secondary to delayed demyelination injury to the nerve. |
