MENINGIOMA

Meningioma

The Meningioma is a primary intracranial tumor that is one of the most common benign tumors within the cranium (head). About 40-60% of benign tumors are meningiomas. About 15% of all primary intracranial tumors (both benign and malignant) are meningiomas. Origin: They originate from the archnoid cap cells that occur most often at the arachnoid granulations which are near the midline adjacent to the superior sagittal sinus (the large midline vein of the head). Another location is the tela choroidea in the ventricles. They are therefore intracranial but not intracerebral (within the head but not in the brain). In other words they occur usually from the covering of the brain called the dura and not from within the brain.

Age:	The peak age is from a 40 to 60 years.
Sex:	It is more common in females than males
Genetics:	72% of tumors have monosomy 22.
Risk factors:	Previous radiation, neurofibromatosis type 2 (NF 2).
Locations:	Cranial (within the head): 90%, spinal canal : 9% and others 1% (neck, parotid etc) About 50% are parasagittal and convexity (near the midline and over the lobes of the brain).
Grading:	WHO classification I,II,III from that least to the most aggressive.
Pathology:	Meningothelial, fibroblastic,psmmomatous, angiomatous, and transitional (most common).
Aggressive variants:	they invade brain, have necrosis, mitosis, papillary, or are locally recurrent.
Malignant:	As above with metastases.
Clinical Features:	They either be symptomatic or asymptomatic at the time of discovery. The usual symptoms may include headaches, seizures, loss of any of the senses (smell, taste, hearing, vision, sensation) , motor weakness (hemiparesis ), memory loss, language problems (dysphasia, aphasia) . Some people with these tumors are mistakenly diagneosed with Dementia , strokes or psychiatric problems.
Diagnostic tests:	This includes a thorough neurological examination followed by brain scanning. In an emergency situation a CT of the brain with contrast can be done quickly, but an MRI of the brain with gadolinium is still the definitive test. The appearance of a meningioma on these tests is usally unique or characteristic enough for an accurate diagnosis most of the time. There are exceptions where a biopsy with tissue examination is still needed.

Biopsy

A biopsy is not mandatory for the diagnosis of a meningioma. MRI and even CT of the brain can be fairly clear in determining the diagnosis of a meningioma. The presence of an intracranial but extracerebral enhancing tumor with a dural tail is a classical finding.

A biopsy can be done by the technique of stereotactic computer aided biopsy where a needle is guided to the tumor after detailed computer planning is done based on pre-surgical imaging and using a stereotactic frame. There is also the technique of frameless stereotaxis using a system like the SteathStation.

Surgery

Microsurgery using a high definition microscope and microinstruments is the latest type of surgery for meningiomas. CAN/CAM technology can also be used. Lasers,”Super-Lasers”,CUSAs and the Malis technique can be used for tumor removal. The StealthStation and other neuro-navigation systems are useful in allowing a minimally invasive approach in the removal of these tumors.

Radiosurgery

Radiosurgery refers to computer planned, and accurately focused high energy beams that are used for non-invasive tumor treatment. Radiosurgery has been shown to be effective for the treatment of meningiomas. Modern systems in use include the Gamma-knife, Novalis type systems and the latest system of Tomotherapy. The two ways in which the treatments can be given are either in a single session or in multiple sessions. The latter is often referred to as SRT (stereotactic radiation therapy) or FSR (fractionated stereotactic radiosurgery).

Medications

There are few anti-meningioma medications. One of them is hydroxyurea.

Combined treatment

Combined Microsurgery and Radiosurgery (CMR) is where both modalities are used for the treatment of large , difficult to remove, or dangerous location meningioma

TRIGEMINAL NEURALGIA

Trigeminal Neuralgia WHAT IS THE CAUSE OF TRIGEMINAL NEURALGIA? The 5th cranial nerve also known as the trigeminal nerve is the nerve that supplies feeling and movement to the face. Trigeminal neuralgia may be caused by a tumor pressing on the trigeminal nerve or a blood vessel that presses on the trigeminal nerve. In some patients the cause cannot be determined. In 5% of patients, trigeminal neuralgia may be associated with multiple sclerosis. TREATMENT OF TRIGEMINAL NEURALGIA : MEDlCATIONS STEREOTACTTIC RADIOSURGERY RADIOFREQUENCY ELECTROCOAGULATION, GLYCEROL INJECTION. BALLOON COMPRESSION OF THE GASSERIAN GANGLION. MICROVASCULAR DECOMPRESSION (MVD). STEREOTACTIC SURGERY FOR TRIGEMINAL NEURALGIA: Stereotactic radiosurgical treatment of Trigeminal Neuralgia is the most recent and least invasive neurosurgical treatment for Trigeminal Neuralgia. It is also the neurosugical treatment that is least likely to cause complications as no surgical opening is made so the major risks of surgery which are infection, bleeding and death do not occur. Also the risk of causing facial numbness and new facial sensations (dysesthesias) are very much less than other surgical procedures. SUITABLE CANDIDATE Any patient with trigeminal neuralgia who has failed medication because of lack of pain relief or undesirable side-effects is an excellent candidate for Stereotactic Radiosurgery. As Radiosurgery does not involve any open surgery, elderly patients and patients with other medical conditions can undergo radiosurgery. Also patients who have undergone other procedures for trigeminal neuralgia may undergo radiosurgery. GAMMA-KNIFE OR LINAC RADIOSURGERY ? Both the Linear Accelerator and the Gamma-knife are tools for Stereotactic Radiosurgery. HOW DOES STEREOTACTIC RADIOSURGERY WORK TO TREAT TRIGEMIMAL NEURALGIA? Stereotactic Radiosurgery is designed to deliver a high dose of radiation in one session to the target lesion with scapel-like precision, with minimal damage to surrounding tissue. For trigeminal neuralgia the target is the trigeminal nerve close to where it leaves the brain. A stereotactic frame or navigation box is fixed to the patient's head. The treatment is a day-surgery procedure. The patient can return to his normal activities immediately after treatment. 4 STAGES OF STEREOTACTIC RADIOSURGERY TREATMENT Stage 1 A navigation box is firmly fixed to the patients skull. This allows for the precision and accuracy of treatment stereotactic radiosurgery. Stage 2 The patient is sent for a treatment planning MRI of the brain. Stage 3 The neurosurgeon and his team (which includes the radiation oncologist, and the physicist) using 3-dimensional computer images plan the treatment and decide on the radiation dose to be given. The Neurosurgeon is the leader of the team as he is the brain expert. Stage 4 The patient lies down on the treatment couch for the radiosurgery treatment. This is an entirely painless procedure. At the end of the stereotactic radiosurgery treatment, the Neurosurgeon removes the navigation box. WHAT ARE THE RESULTS ? Studies done in Sweden, the USA, Japan arid Singapore show that good pain relief is obtained in 80 - 90% of patients.

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PITUITARY TUMOR

Pituitary Tumors These are tumors that occur from the pituitary gland which can be described as the “Master” hormone gland of the body which is located below the base of the brain and in front of the brainstem . It sits in a bony fossa (depression) called the sellar turcica. It is divided into an anterior lobe and a posterior lobe (with a small intermediate lobe). Pituitary tumors account for about 15% of all intracranial tumors. Mean age: 20 to 50 years Sex: More females and males for prolactin and ACTH secreting tumors and a male predominance for GH-producing tumors. Microadenomas are tumors less than 10mm in size and Macroadenomas are more than 10mm in size. Local invasion can occur with macroadnenomas particularly into the skull base regions such as the cavernous sinus. Superior growth of macroadenomas can compress the optic chiasm/optic nerves and cause visual disturbances. Malignancy is rare (<1%> Prolactin producing tumors are the most frequent type of pituitary tumor (30%). Failure of menstruation (amenorrhea) and milk production from the breasts in non-pregnant females (galactorrhea) are the common symptoms. In men decreased libido and impotence and visual loss are commoner symptoms as the tumors tend to be larger when discovered. Growth hormone secreting tumors are the second commonest hormone producing pituitary tumors (15%). It can cause children to grow into “giants” (gigantism) and break height records in their communities. In adults it can cause acromegaly with an enlarged head, hands and feet. ACTH producing tumors (10%) can cause Cushing’s disease. Such patients have central obesity, a moonface, and abdominal marks called striae. TSH secreting tumors are rare (1%) and and cause symptoms of hyperthyroidism. Null cell tumors are the second most common tumor and do not produce hormones (25%). They can grow to a large size and cause visual loss before detection. They can be invasive. Diagnosis of pituitary tumors: This is based on the clinical symptoms and signs mentioned above. An emergency situation can be created by sudden bleeding in a tumor called pituitary apoplexy. This can cause sudden loss of vision and even collapse and coma. Blood tests of all the common pituitary hormones is carried out. Vision tests such as Visual Fields and retinal photographs can reveal visual loss and its extent. MRI with contrast (gadolinium) is superior to CT scanning in diagnosis particularly for the smaller microadenoams. Some patients with ACTH producing microadenomas are difficult to find and selective venous sampling of the hormone may be required by angiography. Diffrential Diagnosis: Nelson’s syndrome is an enlargement of the pituitary gland caused by a surgical adrenalectomy. Lymphocytic hypophysitis can cause a tumor like appearance but it is an autoimmune disease. Giant cell pituitary granulomas and Tuberculous granulomas can be mistaken for pituitary tumors on MRI or CT. Treatment Hormone secreting tumors which are microadenomas can be treated by oral medications like bromocriptine (parlodel). GH secreting tumors can be treated with oral medication like octreotide. For tumors that do not respond to medical treatment or if patients have side effects from medical treatment then alternatives are surgery or radiosurgery. Surgery: In the past this was carried out using an open craniotomy and then later with open approaches through the nose or above the teeth through the mouth. Modern approaches include Endoscopic approaches through the nasal passages with microsurgical methods. Computer guidance (StealthStation) can be used to guide such minimally invasive microsurgery. Radiosurgery: Gamma knife and stereotactic radiotherapy (SRT) are more focused treatments than traditional radiotherapy. There is a more precise treatment of tumors with less side effects. The latest technologies include Tomotherapy (NeuroTomotherapy). Combined Endosocpy/ Microsurgery and Radiosurgery: In patients with large invasive tumors, combination treatment may be safer and effective than single modality treatments. Ultimately the best treatment methods and choices are determined by an experienced Neurosurgeon based on all the available information and presented to the patient for his or her final decision.

LOW BACK PAIN

Low Back Pain

90% of low back pain occurs when a nerve that travels from the spinal cord through the bones of the spine is pinched or irritated. This results in the muscles of the back tensing up and causing the patient low back pain. The solution to this problem depends on why the nerve is irritated in the first place.

The spinal cord which arises in the brain is an intricate network of nerves, discs and bones. It is protected by the spinal column a s it runs down the back. All our body movements is controlled by the spinal cord. he nerves that run out of the spinal cord to control our movements called the motor nerves.

Nerves that run from the spinal cord to the brain are the sensory nerves and they take messages from the body back to the brain. Together, both the motor and sensory nerves form more than 50 nerver roots, which run through holes called foramina, in the bones of the spinal column. Each one of these nerves roots can potentially cause a problem.

The spinal cord is protected by a soft, flexible disc that separates each bone(vetebrae) in the spine. This disc acts as a shock absorber. The outside rim of the disc is rigid, but the inside is soft and gel-like. Any sort of activity, stress or a mechanical problem in the spine can cause a disc to bulge. The bulging disc may put pressure on a nerve root causing low back pain or leg pain in the patient.

In more severe cases, the disc bulge may cause disc rupture or herniation putting even greater pressure on the nerve root. The nerve roots of the lower back cause not only back pain but also pain that radiates down one or both legs. There may also be muscle weakness, numbness, and changes in reflexes in the legs.The key to treatment is to relieve nerve irritation. Although low back pain can be quite debilitating and severe, in 90% of patients the condition improves without surgery. However, 50% of these patients will have a recurrent episode within one year.

If low back pain occurs acutely because of a recent, specific injury eg, a car accident, you should consult a Doctor immediately. Otherwise, you could try conservative treatment for 2-3 days. The suggestion is to take an anti-inflammatory medicine like ibuprofen and restrict activity for a few days. If the back pain does not improve see your doctor. If conservative treatment does not help, you may have to consider surgery.

The Aging Spine

Our spine also ages just like the rest of our body. As we age, our bodies dehydrate (lose water) and in the spine this causes the discs that cushion and separate our vetebrae to dry out. They become less effective as shock absorbers. The ligaments and bones in the spinal cord also become pliable (or flexible). This results in narrowing of the spinal canal stenosis. In some of us this narrowing can compress the nerve roots in the lower back causing back pain and other symptoms when standing or walking. This condition is' very treatable. If conservative treatment (anti-inflammatory medication, limited activity, physiotherapy) fails, surgery. needs to be considered.

Diagnostic Tests

An MRI of the lumbar-sacral spine helps the neurosurgeon determine the diagnosis and severity of the problem. The findings of the MRI are compared with the patients symptoms before the neurosurgeons considers a procedure.

If Surgery Is Recommended

Neurosurgeons who have been trained in the US, have throughout their 7-year residency program been trained on all treatment options available for diseases of the spine and can therefore determine the best treatment option for a particular spine condition. Spinal surgery involves operating in the region of the spinal cord and the nerves, and therefore precision and delicacy are the keys to a successful and safe procedure. Neurosurgeons unlike orthopedic surgeons often use an operating microscope to help magnify the nerves and discs. This allows for greater precision and a smaller incision. After any type of spine surgery, it is important that patients continue to work with their neurosurgeons on a rehabilitation program which includes physical therapy, medications and reduced activity