Ventricular Shunt
Ventricular Shunt
Definition
Purpose
Demographics
Description
Diagnosis/Preparation
Aftercare
Risks
Normal results
Morbidity and mortality rates
Alternatives
Definition
A ventricular shunt is a tube that is surgically placed in one of the fluid-filled chambers inside the brain (ventricles). The fluid around the brain and the spinal column is called cerebrospinal fluid (CSF). When infection or disease causes an excess of CSF in the ventricles, the shunt is placed to drain it and thereby relieve excess pressure.
Purpose
A ventricular shunt relieves hydrocephalus, a condition in which there is an increased volume of CSF within the ventricles. In hydrocephalus, pressure from the CSF usually increases. It may be caused by a tumor of the brain or of the membranes covering the brain (meninges), infection of or bleeding into the CSF, or
inborn malformations of the brain. Symptoms of hydrocephalus may include headache, personality disturbances and loss of intellectual abilities (dementia), problems in walking, irritability, vomiting, abnormal eye movements, or a low level of consciousness.
Normal pressure hydrocephalus (a condition in which the volume of CSF increases without an increase in pressure) is associated with progressive dementia, problems walking, and loss of bladder control (urinary incontinence). Even though CSF is not thought to be under increased pressure in this condition, it may also be treated by ventricular shunting.
Demographics
The congenital form of hydrocephalus is believed to occur at an incidence of approximately one to four out of every 1,000 births. The incidence of acquired hydrocephalus is not exactly known. The peak ages for the development of hydrocephalus are in infancy, between four and eight years, and in early adulthood. Normal pressure hydrocephalus generally occurs in patients over the age of 60.
Description
The ventricular shunt tube is placed to drain fluid from the ventricular system in the brain to the cavity of the abdomen or to the large vein in the neck (jugular
KEY TERMS
Cerebrospinal fluid— Fluid bathing the brain and spinal cord.
Computed tomography (CT) scan— An imaging technique in which cross-sectional x rays of the body are compiled to create a three-dimensional image of the body’s internal structures.
Dementia— Progressive loss of mental abilities.
Magnetic resonance imaging (MRI)— An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct images of internal structures.
vein). Therefore, surgical procedures must be done both in the brain and at the drainage site. The tubing contains valves to ensure that fluid can only flow out of the brain and not back into it. The valve can be set at a desired pressure to allow CSF to escape whenever the pressure level is exceeded.
A small reservoir may be attached to the tubing and placed under the scalp. This reservoir allows samples of CSF to be removed with a syringe to check the pressure. Fluid from the reservoir can also be examined for bacteria, cancer cells, blood, or protein, depending on the cause of hydrocephalus. The reservoir may also be used to inject antibiotics for CSF infection or chemotherapy medication for meningeal tumors.
Diagnosis/Preparation
The diagnosis of hydrocephalus should be confirmed by diagnostic imaging techniques, such as computed tomography scan (CT scan) or magnetic resonance imaging (MRI), before the shunting procedure is performed. These techniques will also show any associated brain abnormalities. CSF should be examined if infection or tumor of the meninges is suspected. Patients with dementia or mental retardation should undergo neuropsychological testing to establish a baseline psychological profile before the shunting procedure.
As with any surgical procedure, the surgeon must know about any medications or health problems that may increase the patient’s risk. Because infections are both common and serious, antibiotics are often given before and after surgery.
WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?
Ventricular shunting is performed in a hospital operating room by a neurosurgeon, a surgeon who specializes in the treatment of diseases of the brain, spinal cord, and nerves.
Aftercare
To avoid infections at the shunt site, the area should be kept clean. CSF should be checked periodically by the doctor to be sure there is no infection or bleeding into the shunt. CSF pressure should be checked to be sure the shunt is operating properly. The eyes should be examined regularly because shunt failure may damage the nerve to the eyes (optic nerve). If not treated promptly, damage to the optic nerve causes irreversible loss of vision.
Risks
Serious and long-term complications of ventricular shunting are bleeding under the outermost covering of the brain (subdural hematoma), infection, stroke, and shunt failure. When a shunt drains to the abdomen (ventriculoperitoneal shunt), fluid may accumulate in the abdomen or abdominal organs may be injured. If CSF pressure is lowered too much, patients may have severe headaches, often with nausea and vomiting, whenever they sit up or stand.
Normal results
After shunting, the ventricles get smaller within three or four days. This shrinkage occurs even when hydrocephalus has been present for a year or more. Clinically detectable signs of improvement occur within a few weeks. The cause of hydrocephalus, duration of hydrocephalus before shunting, and associated brain abnormalities affect the outcome.
Of patients with normal pressure hydrocephalus who are treated with shunting, 25-80% experience long-term improvement. Normal pressure hydrocephalus is more likely to improve when it is caused by infection of or bleeding into the CSF than when it occurs without an underlying cause.
Morbidity and mortality rates
Complications of shunting occur in 30% of cases, but only 5% are serious. Infections occur in 5-10% of
QUESTIONS TO ASK THE DOCTOR
- Why is a ventricular shunt recommended in my case?
- What is the cause of the hydrocephalus?
- What diagnostic tests will be performed prior to the shunt being placed?
- Where will the shunt be placed?
- Are there any alternatives to a ventricular shunt?
patients, and as many as 80% of shunts develop a mechanical problem at some point and need to be replaced.
Alternatives
In some cases of hydrocephalus, certain drugs may be administered to temporarily decrease the amount of CSF until surgery can be performed. In patients with hydrocephalus caused by a tumor, removal of the tumor often cures the buildup of CSF. Approximately 25% of patients respond to therapies other than shunt placement.
Patients with normal pressure hydrocephalus may experience a temporary improvement in walking and mental abilities upon the temporary drainage of a moderate amount of CSF. This improvement may be an indication that shunting will improve their condition.
Resources
BOOKS
Aldrich, E. Francois, Lawrence S. Chin, Arthur J. DiPatri, and Howard M. Eisenberg. “Hydrocephalus.” In Sabiston Textbook of Surgery, edited by Courtney M. Townsend Jr. 16th ed. Philadelphia: W. B. Saunders Company, 2001.
Golden, Jeffery A., and Carsten G. Bonnemann. “Hydrocephalus.” In Textbook of Clinical Neurology, edited by Christopher G. Goetz and Eric J. Pappert. Philadelphia: W. B. Saunders Company, 1999.
PERIODICALS
Hamid, Rukaiya K. A., and Philippa Newfield. “Pediatric Neuroanesthesia: Hydrocephalus.” Anesthesiology Clinics of North America 19, no. 2 (June 1, 2001): 207–18.
ORGANIZATIONS
American Academy of Neurology. 1080 Montreal Ave., St. Paul, MN 55116. (800) 879-1960. http://www.aan.com.
OTHER
Dalvi, Arif. “Normal Pressure Hydrocephalus.” eMedicine, January 14, 2002 [cited May 21, 2003]. http://www.emedicine.com/neuro/topic277.htm.
Hord, Eugenia-Daniela. “Hydrocephalus.” eMedicine, January 14, 2002 [cited May 21, 2003]. http://www.emedicine.com/neuro/topic161.htm.
Sgouros, Spyros. “Management of Spina Bifida, Hydrocephalus, and Shunts.” eMedicine, May 14, 2003. [cited May 21, 2003]. http://www.emedicine.com/ped/topic2976.htm.
Laurie Barclay, MD
Stephanie Dionne Sherk
Ventricular Shunt
Ventricular Shunt
Definition
Ventricular shunt is a surgical procedure in which a tube is placed in one of the fluid-filled chambers inside the brain (ventricles). The fluid around the brain and the spinal column is called the cerebrospinal fluid. When infection or disease causes an excess of this cerebrospinal fluid in the ventricles, the shunt is placed to drain it and thereby relieve excess pressure.
Purpose
Ventricular shunt relieves hydrocephalus, a condition in which the ventricles are enlarged. In hydrocephalus, pressure from the cerebrospinal fluid usually increases. It may be caused by tumor of the brain or of the membranes covering the brain (meninges), infection of or bleeding into the cerebrospinal fluid, or inborn malformations of the brain. Symptoms of hydrocephalus may include headache, personality disturbances and loss of intellectual abilities (dementia ), problems in walking, irritability, vomiting, abnormal eye movements, or a low level of consciousness.
Normal pressure hydrocephalus is associated with progressive dementia, problems in walking, and loss of bladder control (urinary incontinence ). Even though the cerebrospinal fluid is not thought to be under increased pressure in this condition, it may also be treated by ventricular shunting.
Precautions
As with any surgical procedure, the surgeon must know about any medications or health problems that may increase the patient's risk. Because infections are both common and serious complications, antibiotics are often given before and after surgery.
Description
The ventricular shunt tube is placed to drain fluid from the ventricular system in the brain to the cavity of the abdomen or to the large vein in the neck (jugular vein). Therefore, surgical procedures must be done both in the brain and at the drainage site. The tubing contains valves to insure that fluid can only flow out of the brain and not back into it. The valve can be set at a desired pressure to allow cerebrospinal fluid to escape whenever the pressure level is exceeded.
A small reservoir may be attached to the tubing and placed under the scalp. This reservoir allows samples of cerebrospinal fluid to be removed with a syringe to check the pressure. Fluid from the reservoir can also be examined for bacteria, cancer cells, blood, or protein, depending on the cause of hydrocephalus. The reservoir may also be used to inject antibiotics for cerebrospinal fluid infection or chemotherapy medication for meningeal tumors.
Preparation
The diagnosis of hydrocephalus should be confirmed by diagnostic techniques that make images of the brain, such as computed tomography scan (CT scan) or magnetic resonance imaging (MRI), before the shunting procedure is performed. These techniques will also show any associated brain abnormalities. Cerebrospinal fluid should be examined if infection or tumor of the meninges is suspected. Patients with dementia or mental retardation should undergo neuropsychological testing to establish a baseline psychological profile before the shunting procedure.
Patients with normal pressure hydrocephalus may experience a temporary improvement in walking and mental abilities upon removal of a moderate amount of cerebrospinal fluid. This improvement may be an indication that shunting will improve their condition. However, patients who do not improve after temporary cerebrospinal fluid drainage may still benefit from ventricular shunt. When a case is in doubt, continuous monitoring of cerebrospinal fluid pressure (which in itself requires a surgical procedure) may indicate whether shunting is likely to be helpful.
Aftercare
To avoid infections at the shunt site, the area should be kept clean. Cerebrospinal fluid should be checked periodically by the doctor to be sure there is no infection or bleeding into the shunt. Cerebrospinal fluid pressure should be checked to be sure the shunt is operating properly. The eyes should be examined regularly because shunt failure may damage the nerve to the eyes (optic nerve). If not treated promptly, damage to the optic nerve causes irreversible loss of vision. Patients or caregivers should understand the life-threatening nature of shunt problems. All symptoms and signs of potential shunt failure or infection must be taken seriously.
Risks
Complications of shunting occur in 30% of cases, but only 5% are serious. Serious and long-term complications are bleeding under the outermost covering of the brain (subdural hematoma ), infection, stroke, and shunt failure. Infection at the shunt site may cause a loss of intelligence. When shunts drain to the abdomen (ventriculoperitoneal shunts), fluid may accumulate in the abdomen or abdominal organs may be injured. If cerebrospinal fluid pressure is lowered too much, patients may have severe headaches, often with nausea and vomiting, whenever they sit up or stand.
Normal results
Of patients with normal pressure hydrocephalus who are treated with shunting, 25-80% experience long-term improvement. Normal pressure hydrocephalus is more likely to improve when it is caused by infection of or bleeding into the cerebrospinal fluid than when it occurs without an underlying cause. Walking difficulties and bladder control are more likely to improve than dementia is.
After shunting, the ventricles get smaller within three or four days. This shrinkage occurs even when hydrocephalus has been present for a year or more. Clinically detectable signs of improvement occur within a few weeks. The cause of hydrocephalus, duration of hydrocephalus before shunting, and associated brain abnormalities affect the outcome.
Resources
ORGANIZATIONS
American Academy of Neurology. 1080 Montreal Ave., St. Paul, MN 55116. (612) 695-1940. 〈http://www.aan.com〉.
KEY TERMS
Cerebrospinal fluid— Fluid bathing the brain and spinal cord.
Computed tomography (CT) scan— An imaging technique in which cross-sectional x rays of the body are compiled to create a three-dimensional image of the body's internal structures.
Dementia— Progressive loss of mental abilities.
Magnetic resonance imaging (MRI)— An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct images of internal structures.
Ventricular Shunt
Ventricular shunt
Definition
A ventricular shunt is a tube that is surgically placed in one of the fluid-filled chambers inside the brain (ventricles). The fluid around the brain and the spinal column is called cerebrospinal fluid (CSF). When infection or disease causes an excess of CSF in the ventricles, the shunt is placed to drain it and thereby relieve excess pressure.
Purpose
A ventricular shunt relieves hydrocephalus, a condition in which there is an increased volume of CSF within the ventricles. In hydrocephalus, pressure from the CSF usually increases. It may be caused by a tumor of the brain or of the membranes covering the brain (meninges), infection of or bleeding into the CSF, or inborn malformations of the brain. Symptoms of hydrocephalus may include headache, personality disturbances and loss of intellectual abilities (dementia), problems in walking, irritability, vomiting, abnormal eye movements, or a low level of consciousness.
Normal pressure hydrocephalus (a condition in which the volume of CSF increases without an increase in pressure) is associated with progressive dementia, problems walking, and loss of bladder control (urinary incontinence). Even though CSF is not thought to be under increased pressure in this condition, it may also be treated by ventricular shunting.
Demographics
The congenital form of hydrocephalus is believed to occur at an incidence of approximately one to four out of every 1,000 births. The incidence of acquired hydrocephalus is not exactly known. The peak ages for the development of hydrocephalus are in infancy, between four and eight years, and in early adulthood. Normal pressure hydrocephalus generally occurs in patients over the age of 60.
Description
The ventricular shunt tube is placed to drain fluid from the ventricular system in the brain to the cavity of the abdomen or to the large vein in the neck (jugular vein). Therefore, surgical procedures must be done both in the brain and at the drainage site. The tubing contains valves to ensure that fluid can only flow out of the brain and not back into it. The valve can be set at a desired pressure to allow CSF to escape whenever the pressure level is exceeded.
A small reservoir may be attached to the tubing and placed under the scalp. This reservoir allows samples of CSF to be removed with a syringe to check the pressure. Fluid from the reservoir can also be examined for bacteria, cancer cells, blood, or protein, depending on the cause of hydrocephalus. The reservoir may also be used to inject antibiotics for CSF infection or chemotherapy medication for meningeal tumors.
Diagnosis/Preparation
The diagnosis of hydrocephalus should be confirmed by diagnostic imaging techniques, such as computed tomography scan (CT scan) or magnetic resonance imaging (MRI), before the shunting procedure is performed. These techniques will also show any associated brain abnormalities. CSF should be examined if infection or tumor of the meninges is suspected. Patients with dementia or mental retardation should undergo neuropsychological testing to establish a baseline psychological profile before the shunting procedure.
As with any surgical procedure, the surgeon must know about any medications or health problems that may increase the patient's risk. Because infections are both common and serious, antibiotics are often given before and after surgery.
Aftercare
To avoid infections at the shunt site, the area should be kept clean. CSF should be checked periodically by the doctor to be sure there is no infection or bleeding into the shunt. CSF pressure should be checked to be sure the shunt is operating properly. The eyes should be examined regularly because shunt failure may damage the nerve to the eyes (optic nerve). If not treated promptly, damage to the optic nerve causes irreversible loss of vision.
Risks
Serious and long-term complications of ventricular shunting are bleeding under the outermost covering of the brain (subdural hematoma), infection, stroke, and shunt failure. When a shunt drains to the abdomen (ventriculoperitoneal shunt), fluid may accumulate in the abdomen or abdominal organs may be injured. If CSF pressure is lowered too much, patients may have severe headaches, often with nausea and vomiting, whenever they sit up or stand.
Normal results
After shunting, the ventricles get smaller within three or four days. This shrinkage occurs even when hydrocephalus has been present for a year or more. Clinically detectable signs of improvement occur within a few weeks. The cause of hydrocephalus, duration of hydrocephalus before shunting, and associated brain abnormalities affect the outcome.
Of patients with normal pressure hydrocephalus who are treated with shunting, 25–80% experience long-term improvement. Normal pressure hydrocephalus is more likely to improve when it is caused by infection of or bleeding into the CSF than when it occurs without an underlying cause.
Morbidity and mortality rates
Complications of shunting occur in 30% of cases, but only 5% are serious. Infections occur in 5–10% of patients, and as many as 80% of shunts develop a mechanical problem at some point and need to be replaced.
Alternatives
In some cases of hydrocephalus, certain drugs may be administered to temporarily decrease the amount of CSF until surgery can be performed. In patients with hydrocephalus caused by a tumor, removal of the tumor often cures the buildup of CSF. Approximately 25% of patients respond to therapies other than shunt placement.
Patients with normal pressure hydrocephalus may experience a temporary improvement in walking and mental abilities upon the temporary drainage of a moderate amount of CSF. This improvement may be an indication that shunting will improve their condition.
Resources
books
aldrich, e. francois, lawrence s. chin, arthur j. dipatri, and howard m. eisenberg. "hydrocephalus." in sabiston textbook of surgery, edited by courtney m. townsend jr. 16th ed. philadelphia: w. b. saunders company, 2001.
golden, jeffery a., and carsten g. bonnemann. "hydrocephalus." in textbook of clinical neurology, edited by christopher g. goetz and eric j. pappert. philadelphia: w. b. saunders company, 1999.
periodicals
hamid, rukaiya k. a., and philippa newfield. "pediatric neuroanesthesia: hydrocephalus." anesthesiology clinics of north america 19, no. 2 (june 1, 2001): 207–18.
organizations
american academy of neurology. 1080 montreal ave., st. paul, mn 55116. (800) 879-1960. <http://www.aan.com>.
other
dalvi, arif. "normal pressure hydrocephalus." emedicine, january 14, 2002 [cited may 21, 2003]. <http://www.emedicine.com/neuro/topic277.htm>.
hord, eugenia-daniela. "hydrocephalus." emedicine, january 14, 2002 [cited may 21, 2003]. <http://www.emedicine.com/neuro/topic161.htm>.
sgouros, spyros. "management of spina bifida, hydrocephalus, and shunts." emedicine, may 14, 2003. [cited may 21, 2003]. <http://www.emedicine.com/ped/topic2976.htm>.
Laurie Barclay, MD Stephanie Dionne Sherk
WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?
Ventricular shunting is performed in a hospital operating room by a neurosurgeon, a surgeon who specializes in the treatment of diseases of the brain, spinal cord, and nerves.
QUESTIONS TO ASK THE DOCTOR
- Why is a ventricular shunt recommended in my case?
- What is the cause of the hydrocephalus?
- What diagnostic tests will be performed prior to the shunt being placed?
- Where will the shunt be placed?
- Are there any alternatives to a ventricular shunt?
Ventricular Shunt
Ventricular shunt
Definition
A ventricular shunt is a tube that is surgically placed in one of the fluid-filled chambers inside the brain (ventricles). The fluid around the brain and the spinal column is called cerebrospinal fluid (CSF). When infection or disease causes an excess of CSF in the ventricles, the shunt is placed to drain it and thereby relieve excess pressure.
Purpose
A ventricular shunt relieves hydrocephalus , a condition in which there is an increased volume of CSF within the ventricles. In hydrocephalus, pressure from the CSF usually increases. It may be caused by a tumor of the brain or of the membranes covering the brain (meninges ), infection of or bleeding into the CSF, or inborn malformations of the brain. Symptoms of hydrocephalus may include headache , personality disturbances and loss of intellectual abilities (dementia ), problems in walking, irritability, vomiting, abnormal eye movements, or a low level of consciousness.
Normal pressure hydrocephalus (a condition in which the volume of CSF increases without an increase in pressure) is associated with progressive dementia, problems walking, and loss of bladder control (urinary incontinence). Even though CSF is not thought to be under increased pressure in this condition, it may also be treated by ventricular shunting.
Demographics
The congenital form of hydrocephalus is believed to occur at an incidence of approximately one to four out of every 1,000 births. The incidence of acquired hydrocephalus is not exactly known. The peak ages for the development of hydrocephalus are in infancy, between four and eight years, and in early adulthood. Normal pressure hydrocephalus generally occurs in patients over the age of 60.
Description
The ventricular shunt tube is placed to drain fluid from the ventricular system in the brain to the cavity of the abdomen or to the large vein in the neck (jugular vein). Therefore, surgical procedures must be done both in the brain and at the drainage site. The tubing contains valves to ensure that fluid can only flow out of the brain and not back into it. The valve can be set at a desired pressure to allow CSF to escape whenever the pressure level is exceeded. In some cases where only brief drainage is needed, the shunt tube may simply drain to the outside.
A small reservoir may be attached to the tubing and placed under the scalp. This reservoir allows samples of CSF to be removed with a syringe to check the pressure. Fluid from the reservoir can also be examined for bacteria, cancer cells, blood, or protein, depending on the cause of hydrocephalus. The reservoir may also be used to inject antibiotics for CSF infection or chemotherapy medication for meningeal tumors.
Diagnosis/Preparation
The diagnosis of hydrocephalus should be confirmed by diagnostic imaging techniques such as computed tomography scan (CT scan ) or magnetic resonance imaging (MRI) before the shunting procedure is performed. These techniques will also show any associated brain abnormalities. CSF should be examined if infection or tumor
of the meninges is suspected. Patients with dementia or mental retardation should undergo neuropsychological testing to establish a baseline psychological profile before the shunting procedure.
As with any surgical procedure, the surgeon must know about any medications or health problems that may increase the patient's risk. Because infections are both common and serious, antibiotics are often given before and after surgery.
Aftercare
To avoid infections at the shunt site, the area should be kept clean. The physician should periodically check CSF to be sure there is no infection or bleeding into the shunt. CSF pressure should be checked to be sure the shunt is operating properly. The eyes should be examined regularly because shunt failure may damage the nerve to the eyes (optic nerve). If not treated promptly, damage to the optic nerve causes irreversible loss of vision.
Risks
Serious and long-term complications of ventricular shunting are bleeding under the outermost covering of the brain (subdural hematoma ), infection, stroke , and shunt failure. When a shunt drains to the abdomen (ventriculoperitoneal shunt), fluid may accumulate in the abdomen or abdominal organs may be injured. If CSF pressure is lowered too much, patients may have severe headaches, often with nausea and vomiting, whenever they sit up or stand.
Normal results
After shunting, the ventricles get smaller within three or four days. This shrinkage occurs even when hydrocephalus has been present for a year or more. Clinically detectable signs of improvement occur within a few weeks. The cause of hydrocephalus, duration of hydrocephalus before shunting, and associated brain abnormalities affect the outcome.
Of patients with normal pressure hydrocephalus who are treated with shunting, 25–80% experience long-term improvement. Normal pressure hydrocephalus is more likely to improve when it is caused by infection of or bleeding into the CSF than when it occurs without an underlying cause.
Morbidity and mortality rates
Complications of shunting occur in 30% of cases, but only 5% are serious. Infections occur in 5–10% of patients, and as many as 80% of shunts develop a mechanical problem at some point and need to be replaced.
Alternatives
In some cases of hydrocephalus, certain drugs may be administered to temporarily decrease the amount of CSF until surgery can be performed. In patients with hydrocephalus caused by a tumor, removal of the tumor often cures the buildup of CSF. Approximately 25% of patients respond to therapies other than shunt placement.
Patients with normal pressure hydrocephalus may experience a temporary improvement in walking and mental abilities upon the temporary drainage of a moderate amount of CSF. This improvement may be an indication that shunting will improve their condition.
Resources
BOOKS
Aldrich, E. Francois, Lawrence S. Chin, Arthur J. DiPatri, and Howard M. Eisenberg. "Hydrocephalus." Sabiston Textbook of Surgery, edited by Courtney M. Townsend Jr. 16th ed. Philadelphia: W. B. Saunders Company, 2001.
Golden, Jeffery A., and Carsten G. Bonnemann. "Hydrocephalus." Textbook of Clinical Neurology, edited by Christopher G. Goetz and Eric J. Pappert. Philadelphia: W. B. Saunders Company, 1999.
PERIODICALS
Hamid, Rukaiya K. A., and Philippa Newfield. "Pediatric Neuroanesthesia: Hydrocephalus." Anesthesiology Clinics of North America 19, no. 2 (June 1, 2001): 207–18.
ORGANIZATIONS
American Academy of Neurology. 1080 Montreal Ave., St. Paul, MN 55116. (800) 879-1960. (March 2, 2004). <http://www.aan.com>.
OTHER
Hord, Eugenia-Daniela. "Hydrocephalus." eMedicine, January 14, 2002 [cited March 2, 2004]. <http://www.emedicine.com/neuro/topic161.htm>.
Dalvi, Arif. "Normal Pressure Hydrocephalus." eMedicine, January 14, 2002 [cited March 2, 2004]. <http://www.emedicine.com/neuro/topic277.htm>.
Sgouros, Spyros. "Management of Spina Bifida, Hydrocephalus, and Shunts." eMedicine, May 14, 2003. [cited March 2, 2004]. <http://www.emedicine.com/ped/topic2976.htm>.
Laurie Barclay, MD
Stephanie Dionne Sherk