The meninges are the coverings of the brain and spinal cord, including, from outside to inside, the tough dura mater, the arachnoid membrane and the delicate pia mater. While a meningocele is a malformation just of the outermost coverings of the spinal cord, a myelomeningocele includes abnormal development of the underlying spinal cord itself. In development, normally the nervous system develops from a plate of cells that fold to become a tube, the neural tube. If the lower end of the tube does not close normally, it can lead to varous forms of spina bifida, meningocele being the most severe. While this represents the most severe form of spina bifida, less severe is just involvement of the meninges, the coverings of the spinal cord, called a meningocele. The most mild form is spina bifida occulta, which does not involve any of the nervous system structures or the meninges, just a small, occult bony spine malformation in the lower back. Because a meningomyelocele includes abnormal development of the end of the spinal cord, neurological symptoms are common. In less severe forms the child may be born with some normal movement of the legs, but in more severe cases they may be born with very significant disability of the movement and sensation of the legs. Even if a child has some reflex movement of the legs at birth, the abnormal spinal cord and poor coverings on the back very frequently lead to further trauma to the spinal cord which can lead to progressive loss of nervous system function. Because the sac is practically open to the outside environment in many cases, there is also a high risk of infection, leading to meningitis. There is a close association with myelomeningocele and hydrocephalus and the Arnold-Chiari Malformation (Type II). Many patients with this malformation will also have hydrocephalus which may require separate treatment. After the malformation is detected, generally some imaging study such as an MRI scan or further ultrasounds are used to distinguish myelomeningocele from other malformations such as meningocele and to evaluate for hydrocephalus and any other malformations which may occur simultaneously. With treatment, outcomes vary considerably. Many patients will have permanent disability of the legs and bowel and bladder dysfunction. Others may preserve some function. Some patients who present with hydrocephalus will require subsequent treatment of the that condition as well. Each case varies and can be very different in size, location, extent of the malformation, etc. Therefore, each individual patient's treatment plan can vary considerably and should be discussed with their own personal physicians. There are several underlying causes that can lead to the formation of a syrinx: A persistent central canal of the spinal cord is sometimes misdiagnosed as a syrinx. Some individuals have a pronounced central canal which may be read as a syrinx by a radiologist. These findings are generally not associated with symptoms and do not enlarge over time as many syrinx do. The symptoms associated with a syrinx are generally progressive as the syrinx enlarges over time, causing more compression and damage to surrounding nervous system structures. In some cases a myelogram may be performed to assess the spinal canal at the level of the syrinx. This entails the injection of a radio-opaque dye into the cerebrospinal fluid in the spinal canal followed by imaging (either X-rays or CT scan, or both). In cases which are refractory to other treatment or which are not associated with another lesion which can be treated, other treatment of the syrinx is occasionally necessary. For example, a syrinx shunt may be performed. Similar to a shunt performed for hydrocephalus. In these procedures, a small catheter is placed into the syrinx which diverts fluid to another location. This can be a shunt directly into the spinal canal or can shunt the fluid to the abdominal cavity where it can be re-absorbed. These treatments aim to decrease the pressure within and around the syrinx, ideally shrinking it and preventing further enlargement and neurological injury. The treatment of syringomyelia can be complex and varies from one patient to the next depending on location, size, underlying cause and symptoms. Each patient should consult their own treating physicians about the most appropriate treatment options in their specific case.What Is It?
A myelomeningocele (sometimes called a meningomyelocele) is the most severe form of spina bifida. It is a congenital malformation that results when an error in the normal development of the nervous system, particularly the spinal cord and spine, occurs. The malformation results in incomplete development of the bottom end of the spinal cord, the spinal nerves and all the soft-tissue and bony coverings on the back of the spine. This results in a sac, filled with cerebrospinal fluid, which bulges out the back, generally in the lower back or lumbar region.What Types of Symptoms Are Typical?
First, these deformities are usually very obvious at birth, presenting as a sac of variable size bulging from the back. Very often the skin and other soft-tissues overlying the sac are malformed as well and often cerebrospinal fluid leads from the area.How Is The Diagnosis Typically Made?
Generally, myelomeningocele is obvious at birth, presenting as a sac with abnormal skin on the lower back, although the size and exact location can vary. In some patients, a pre-natal ultrasound examination can reveal the malformation prior to the time of birth.What Are Some Common Treatments?
Generally, when a child is born with this malformation, urgent surgical correction of the deformity is suggested. The goal of surgery is to remove the excess tissues, to cover and protect the abnormal spinal cord and to close and protect the nervous system structures from the outside environment. These goals aim at preventing further neurological deterioration and preventing infection which can be introduced through the abnormal coverings. While surgery cannot correct that abnormal development of the spinal cord, it can help to correct that abnormality in the coverings of the spine, to help preserve what function there is.Syringomyelia
What Is It?
Syringomyelia is a condition of the spinal cord which can result from various forms of injury to the spinal cord or spinal canal. It is characterized by the formation of a syrinx in the spinal cord, a fluid-filled cyst-like space within the substance of the spinal cord. As it slowly enlarges it can cause damage to the surrounding normal spinal cord leading to neurological symptoms.What Types of Symptoms Are Typical?
The symptoms associated with syringomyelia vary depending on their location and size. In general, enlargement of the syrinx can cause injury to the surrounding spinal cord, compromising nervous system function. This can lead to myelopathic symptoms which can include weakness, sensory symptoms (numbness, tingling, etc.), and bowel and bladder dysfunction. The muscle weakness is generally a spastic paralysis involving areas of the body below the level of the syrinx. A low cervical or thoracic syrinx may therefore lead to symptoms of the legs while a higher cervical syrinx can cause arm symptoms as well.How Is The Diagnosis Typically Made?
In a patient that presents with neurological symptoms consistent with spinal disease, after a neurological examination, an imaging study of the spine is typically performed. While a CT scan may be ordered in some cases, an MRI scan is much more sensitive with better resolution to demonstrate syringomyelia. It can both demonstrate the syrinx as well as any associated pathology such an associated tumor or compression.What Are Some Common Treatments?
The appropriate treatment of syringomyelia depends entirely on the patient's symptoms and the underlying cause of the syrinx in each case. For example, a syrinx associated with a tumor or focal spinal canal compression may be treated primarily by removal of the tumor or decompressive surgery, making room for the spinal cord and syrinx. In these cases, treating the underlying cause may be all that is required to halt the progression or even reverse the syrinx.
Wednesday, March 31, 2010
Labels: Myelomeningocele Syringomyelia
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