Spinal Dysraphism
 
 

Spinal dysraphism [Tethered Spinal Cord Syndrome]

What is Spina Bifida?
The term "Spina Bifida" applies to a failure of the spinal cord and spinal column to form properly before birth. This failure can occur anywhere from the head to the tailbone, but is more common in the lumbar spine. It can occur with a wide range of severity. Spina Bifida Occulta is usually found incidentally and is often of no consequence. Myelomeningocele is a form of Spina Bifida in which the spinal cord is exposed to air at birth. Between these two extremes are other forms, each with its own characteristics

What is a Tethered Spinal Cord Syndrome?
Tethered spinal cord syndrome is a condition caused by abnormal tissue attachments that restrict the movement and ascend of the spinal cord within the spinal column. With the spinal column growing spinal cord stretches beyond its tolerance which can then result in lower spinal cord dysfunction due to the damages of nerve cells and nerve fibers. Tethered spinal cord syndrome may go undiagnosed until late childhood, when sensory and motor problems and loss of bowel and bladder control emerge. Disorders which can lead to tethered cord syndrome include:
Myelomeningocele
Lipomeningocele and spinal cord lipoma
Dermal Sinus Tracts and dermoid
Diastematomyelia or split cord malformation
Neuroentric syst

How is Tethered Cord diagnosed?
Almost all spinal dysraphism have Neurocutaneous marker viz midline dimples, sinuses or tracts leading the skin toward the spinal cord, birthmarks, hairy patches, skin discoloration, skin tags or fatty lumps. Its Nature’s way of warning the clinician that some thing wrong with the development of spinal cord. The most common signs of tethered cord syndrome include loss of bladder or bowel control and/or loss of function in the legs. The symptoms and signs of a tethered cord are not always obvious and may result in a delayed diagnosis. The neurological defect that results from abnormal stretching of the spinal cord may not be reversed by surgery, so it is important to diagnose this condition as soon as possible. Some signs and symptoms include:
Bowel or bladder incontinence
Decrease in strength of legs or feet
Deformity of the legs or hips
Loss of reflexes and sensation in the legs
Stumbling or walking changes
Leg or back pain
Curvature of the spine
Skin abnormalities

What is the treatment for Tethered Cord?
Patients suspected of having tethered cord may go through the following steps for evaluation and treatment:
MRI of the spine
Bladder function evaluation
Somatosensory evoked potentials and Nerve Conduction Studies- to evaluate nerves and electrical impulse transmissions through the spinal cord

Surgery
It is important that a neurosurgical assessment is made as early as possible after the onset of symptoms. In children, early surgery is recommended to prevent further neurological deterioration. The care of patients with tethered cord is very complex and is therefore best handled by pediatric neurosurgeons trained in treating the tethered cord syndrome. The main purpose of the surgery is to stop any further deterioration of neurological function. The surgery (Detether) the spinal cord also  may restore some function or alleviate other symptoms .

What is the prognosis?
With treatment, individuals with tethered spinal cord syndrome have a normal life expectancy unless bladder and Bowel is involved.
After the initial repair, patients need close follow-up by a coordinated team of physicians, nurses, and therapists. They may need to be treated for hydrocephalus, urologic symptoms, scoliosis, tethered cord, or muscle weakness. The exact needs of each patient depends on the type and spinal cord level of their Spina Bifida, making coordination between different members of the Spina Bifida team essential in tailoring the best treatment for each unique patient

Myelomeningocele / Spina Bifida
Spina bifida or myelomeningocele is a condition that occurs when the spinal cord fails to fully form early in development (in the womb, before most women know they are pregnant). Myelomeningocele is one of the most common birth defects of the nervous system. It is a neural tube defect in which the skin , muscle and bones of the spine do not completely formed. This allows the spinal cord and meninges (the membranes covering the spinal cord) to protrude out of the child's back. The spinal cord is exposed through the opening in the spine, resulting in partial or complete paralysis of the parts of the body below the spinal opening. The affected individual may be unable to walk and may have bowel and urinary dysfunction.

Causes
Cause of myelomeningocele is unknown. However, folic acid deficiency is thought to play a part in neural tube defects. Also, if a child is born with myelomeningocele, subsequent children in that family have a higher risk than the general population. A viral cause or trigger has been theorized because there is a higher incidence of the defect in children born in the early winter months. Research also indicates possible environmental factors such as radiation. Other congenital disorders may also be present in the child, usually disorders of the spinal cord or the musculoskeletal system such as hydrocephalus (which may effect as many as 90% of children with myelomeningocele), syringomyelia, hip dislocation, or similar disorders. With the use of folate supplementation in maternal vitamins, the incidence of spina bifida has decreased dramatically. Women who are considering getting pregnant should ask their doctors about a maternal vitamin which contains folate.

Symptoms
The malformed spinal cord is open and visible through the skin of the back. This condition requires treatment within the first few days of life and is commonly associated with hydrocephalus. Spina bifida is also associated with other problems of the brain and spinal cord such as Chiari malformations. Symptoms include partial or complete paralysis of the legs, with partial or complete lack of sensation, and may include loss of bladder or bowel control. The exposed spinal cord is susceptible to infection (meningitis).Visible sac-like protrusion on the mid to lower back of a newborn (not translucent when a light is shone from behind the sac) Weakness of the hips, legs, or feet of a newborn. Myelomeningocele is a visible defect after the child is born. Neurologic examination may indicate loss of neurologic functions below the defect. For example, response of the infant to pinpricks at various locations may indicate the level where sensation is maintained.

Diagnosis
Spine X-Rays may reveal the exact extent and location of the defect
Spine ultrasound may show an abnormal spinal cord or spine
Spine CT or Spine MRI are occasionally used to determine the location and extent of the defect.

Treatment
The goals of initial treatment are to reduce the amount of neurologic damage caused by the defect, to minimize complications such as infection, and to aid the family in coping with the disorder. Follow-up neurological testing as the child gets older helps to guide rehabilitation. Early surgical repair of the defect is usually recommended, although surgical repair may be performed later to allow the infant to tolerate the procedure better. Currently there are centers attempting experimental in utero surgical repair of spina bifida (surgical repair of the defect while the fetus is still developing in the uterus).

Before surgery, the infant must be handled carefully to reduce damage to the exposed spinal cord. This may include positioning, protective devices, and modifications in the methods of handling, feeding, bathing and caring for the infant.

Orthopedic intervention or physical therapy may be needed to treat musculoskeletal symptoms. Other neurologic losses are treated according to the type and extent of the loss of function. The goal of these interventions is to minimize future disability and maximize functioning. Surgical CSF diversion shunting might be needed to correct hydrocephalus.Children with spina bifida are followed at Spina Bifida Clinic


Lipomas and Lipomyelomeningoceles
Spinal cord lipomas are a fatty mass or tumor within the spinal cord and are usually associated with spina bifida but will, in rare circumstances occur among adult men and women who do not have spina bifida. Lipomyelomeningoceles, congenital lesions due to the failure of closure of spinal bones associated with spina bifida.

Symptoms
A gradual stretching of the spinal cord causes numbness or tingling for the patient. In extreme cases, there is weakness, difficulty in urination or bowel movements, incontinence and stiffness of the extremities. Identified by abnormal fat accumulation that starts below the level of the skin and extends through the bony opening to the spinal cord, more than 90 percent of patients will have an obvious soft tissue swelling over the spine in the lumbosacral region. While not painful, patients can lose neurological function over a broad range of time. Typical neurological symptoms for adolescents and adults are weakness and bladder and bowel incontinence. Pain may be the force behind seeking treatment.

Diagnosing and Treating Spinal Cord Lipomas and Lipomyelomeningoceles


MRI's give exceptional anatomical details and can help surgeons plan the operative procedure. Conventional x-rays will show spina bifida in most cases.
Surgical treatment is indicated at six months of age or at the time of diagnosis if the patient is older. The goals of surgery are to release the attachment of the fat to the spinal cord and reduce the bulk of the fatty tumor through a laminectomy .  

Dermal Sinus Tract
A Congenital Dermal Sinus is a tract lined by stratified squamous epithelium found in, or very near, the midline anywhere from the nasal bridge to the coccyx (tailbone). The tract may end just below the skin surface or may extend to the conus medullaris (part of the spinal cord) or the central canal of the spinal cord from the back, the fourth ventricle from the occipital region, or the crista galli from the nasal bridge.

Symptoms
A Spinal Dermal Sinus may appear as a dimple or a sinus (open tract), with or without hairs, usually very close to the midline, with an opening of only 1-2 millimeters. The surrounding skin may be normal, pigmented, or distorted by an underlying mass. These tracts are a potential pathway for intradural infections, which may result in meningitis and/or an abscess. The contents of the dermal sinus causing sterile (chemical) meningitis may also irritate the superficial skin. If the tract expands into the thecal sac (the sac that contains the spinal cord) to form a cyst, the mass may present as a tethered cord. In these circumstances bladder dysfunction is usually the first manifestation.

Diagnosis
If the tract is seen initially following birth, a MRI should be obtained. MRI also shows masses within the canal.

Treatment
Sinuses above the lumbosacral region should be surgically removed. Although approximately 25% of presumed sacral sinuses seen at birth will regress to a deep dimple on follow-up, it is recommended that all dermal sinuses should be surgically explored and fully excised prior to the development of neurologic deficit or signs of infection. The results following intradural infection are never as good as when undertaken prior to infection. Sinuses that terminate on the tip of the coccyx rarely penetrate the dura, and may not need to be treated unless local infection occurs.


Diastematomyelia - Split Cord Malformation
Split cord malformation (Diastematomyelia) is a complex congenital condition where the spinal cord is split into two halves, each half usually functioning normally. The split is in a plane running front to back. The split in the cord can occur at any level and the split cords may reunite or not at some point below the split. Occasionally there is no obvious cause of the split but usually there is bone, cartilage or fibrous tissue that is between the two halves of the spinal cord. The presence of the tissue splitting the spinal cord causes tethering. The surgical procedure is to remove any tissue that is between the two split cords, thus releasing any tethering that is present.

What are the symptoms?
The signs and symptoms of Diastematomyelia may appear at any time of life, although females are affected much more commonly than males. Pain is the number one reason patients will visit their doctor for this problem. Other common symptoms include a decrease in strength of the legs; loss of bowel and bladder control; sexual dysfunction; deformity of the legs, feet or hips; back or leg pain; loss of reflexes and sensation in the legs; and curvature of the spine. Often there are skin abnormalities overlying the tethered cord such as midline dimples, sinuses or tracts leading from the skin toward the spinal cord, birthmarks, fatty lumps, or small tufts of hair.

What is the prognosis?
The presence of Diastematomyelia has no influence on the prognosis when spina bifida is present. When diastematomyelia presents as a closed neural tube defect, the prognosis for neurological function may be enhanced by early surgical removal of the septum, dural reconstruction into a single tube, excision of associated developmental masses and division of the tethering filum.

 
Clinic at Mulund (West)
 

         
    M.B.B.S.
M.S.(General Surgery)
D.N.B.(General Surgery)
M.CH.(Neuro Surgery)
D.N.B.(Neuro Surgery)
M.N.A.M.S
 
         
         
 
  Fellowship in Pediatric
Neurosurgery from Tel
AVIV & Great Ormand
Street Hospital for Sick
Children, London, U.K.
 
         
         
 
  Registration No.:
83299
(Maharashtra Medical
Council)