Chiari Malformation and Tethered Cord

Tethered Spinal Cord or Occult Tethered Cord Syndrome (TC or OTC) This causes the spinal cord to be pulled taut and is either congenital or from a form or spinal trauma. The cord attaches itself to tissue and if left untreated can cause irreversible damage. In the case of OTC it means there have been no findings on the MRI but the patient presents with symptoms and tends to have urology issues that can be tested and reported on.

Chiari Malformation (CM) Where the brain is too large for the skull or there has been trauma that allows the hindbrain (cerebellar tonsils) to get pushed out of the bottom of the skull into the spinal canal. This can then block spinal fluid moving around properly and cause very painful symptoms. It would appear that patients with EDS do not always have classic Chiari, as stated on my MRI report, a large herniation consistent with Ehlers Danlos Syndrome and different from that seen in classic CM. From that believe acquired CM can be caused by a combination of EDS, CCI and TC. All these things can have an effect on the spinal cord, brainstem and cerebral spinal fluid.

This is not a medical website, merely a collection of information, ideas and personal experiences. For more technical information please see below.

 

Tethered Cord Syndrome is a neurological disorder that is caused by tissue attachments. It limits the movement of the spinal cord and causes a pulling effect.  Attachments can occur congenitally at the bottom of the spinal cord or they can happen near the site of an injury to the spinal cord.  The attachments cause an abnormal stretching of the spinal cord and can make various positions quite uncomfortable. The course of the disorder is progressive so it is important to try and get diagnosis as soon as possible.  In children, symptoms may include lesions, hairy patches, dimples, or fatty tumours on the lower back; foot and spinal deformities; weakness in the legs; low back pain; scoliosis; and incontinence.  This type of tethered spinal cord syndrome appears to be the result of improper growth of the neural tube during foetal development, and is closely linked to spina bifida.  Tethered spinal cord syndrome may go undiagnosed until adulthood, when pain, sensory and motor problems, and loss of bowel and bladder control emerge.  This delayed presentation of symptoms is related to the degree of strain placed on the spinal cord over time and may be exacerbated during sports or pregnancy, or may be due to narrowing of the spinal column (stenosis) with age. Tethering may also develop after spinal cord injury and scar tissue can block the flow of fluids around the spinal cord.  Fluid pressure may cause cysts to form in the spinal cord, a condition called Syringomyelia. This can lead to additional loss of movement, feeling or the onset of pain or autonomic symptoms.

tethered-cord-syndrome

 

Occult Tethered Cord

This differs from Tethered Cord Syndrome and is still regarded by some in the medical community as controversial, mainly due to there being no diagnostic MRI findings. It would appear that more urologic symptoms appear with this than Tethered Cord Syndrome, with incontinence showing more than pain.  A scholarly review was conducted of 22 paediatric cases of surgical untethering for suspected occult tight filum terminale syndrome. All patients had non diagnostic MRI findings, defined as conus medullaris above the L3 vertebral body and a filum terminale diameter of less than 2 mm. Preoperative symptoms, signs and urodynamic test results were collected and compared with surgical outcomes determined by clinical notes and postoperative urodynamic reports. Abnormal findings on presentation were categorized as dermatologic, urologic, orthopaedic and neurologic. Results: Patient age ranged from 7 months to 17 years, and 12 were female. Sixteen (73%) patients experienced subjective and/or objective improvement following surgical untethering. Fourteen patients had abnormal preoperative urodynamic testing, of which 12 underwent postoperative urodynamic testing. Five of these 12 (42%) demonstrated objective improvement postoperatively. Patients presenting with abnormal findings in at least 2 categories were more likely to improve following untethering (88%) than those with abnormalities in only 1 category (20%; p = 0.009). Conclusion: Spinal cord untethering is a treatment option for occult tight filum terminale syndrome. Further evaluation of the relationship between preoperative findings and surgical outcomes may facilitate the selection of surgical candidates.

 

Treatment

MRI imaging is often used to evaluate individuals with tethered cord symptoms, and can be used to diagnose the location of the tethering, lower than normal position of the conus medullaris, or presence of a tumour or fatty mass (lipoma).  In children, early surgery is recommended to prevent further neurological deterioration. Regular follow-up is important: retethering may occur in some individuals during periods of rapid growth and may be seen between five to nine years of age.  If surgery is not advisable, spinal cord nerve roots may be cut to relieve pain.  In adults, surgery to free (detether) the spinal cord can reduce the size and further development of cysts in the cord and may restore some function or alleviate other symptoms.

You tube video This is an informative video with Dr Holly Gilmer in USA.

NHS Document This is information from the NHS regarding some useful exercises and what sort of thing to expect before and after surgery. Bear in mind this may be different in Spain but provides you with an idea of what to expect.

 

Chiari Malformation

In someone with Chiari I, the lowest part of the back of the brain extends into the spinal canal. This can put pressure on the brainstem, spinal cord, and obstruct the flow of fluid. There are four main types, but type 1, called Chiari I, is the most common. Now in the EDS community it would appear that Cerebellar Tonsil herniations can show very differently on an upright MRI. It has been noted on my MRI report that this type of herniation differs from that of classic Chiari Malformation. Again it fits with the fact that once gravity and movement are involved our spines and tissue look very different to that of a non EDS person.

If surgery is required then a posterior fossa decompression is carried out to create more room in order for cerebral spinal fluid to circulate properly. Here is the link for the NHS information sheet NHS document

Here is a link for potential useful items pre and post op  Forum discussion

 

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Information sourced and referenced 28.10.2016:

source 1

source 2

source 3

source 4

Tethered cord image from Image source 1

Chiari malformation image from Image source 2