Tethered cord syndrome
Updates to Article Attributes
Tethered cord syndrome, also known as an occult spinal dysraphism sequence, is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal canal.
Clinical presentation
Tethered cord syndrome is a clinical diagnosis based on neurologic deterioration 7. Patients may present with any combination of the following 4:
- progressive leg weakness or sensory loss
- disturbance of bowel or bladder function
- low back pain or sciatica
- spinal deformities such as scoliosis
- foot deformities such as pes cavus
- cutaneous stigmata of spinal dysraphism (e.g. hairy patch, dimple, subcutaneous lipoma)
The condition typically presents in children but occasionally goes undiagnosed until or is acquired in adulthood.
Pathology
The As the spinal column develops at a greater rate grows faster than the spinal cord during fetal development, and abnormal attachments lead to abnormaltethering lesions cause progressive stretching of the spinal cord. Abnormal traction leads to chronic ischemic changes and neuronal dysfunction.
Etiology
Tethered cord syndrome can result from a varietyis associated with most of the major types of spinal dysraphism, except isolated bifid vertebrae (spina bifida occulta) and neurenteric cysts7,11. Moreover, as open spinal dysraphism (mostly myelomeningocele) must be repaired in the neonatal period, those patients with this history who develop tethered cord syndrome do so years later due to adhesions rather than the dysraphism itself 11.
Thus, the most common causes of tethered cord syndrome are closed spinal dysraphisms: spinal lipomas (lipomyelomeningocele, 7 such as myelomeningoceleconus lipoma, tumors, and filar lipoma) and tight filum terminale (with or without filar lipoma) 710,12-14. Other causes include arachnoid adhesions (due to trauma/surgery or infection/inflammation), split cord malformation (diastematomyelia and diplomyelia), dermal sinus tracts, and dermoid/epidermoid tumors 10,14.
Classification
Classifications of etiologies as "primary" or "secondary" tethered cord syndrome are heterogeneous and conflicting in the literature. For instance, primary tethered cord syndrome may refer to all congenital causes in general, closed spinal dysraphisms as a group, or tight filum terminale in particular 3,8,9,15. Without a consensus nomenclature, this classification isthese terms are best avoided.
Radiographic features
Most commonly, the conus medullaris terminates in a low position below the level of the L2 vertebral body 1. However, tethered cord syndrome is possible in the setting of a normal conus position 5,7.
Additional imaging features depend on the etiology, which are described separately:
Commonly associated
Ultrasound
Ultrasound may be a useful screening exam and may be of use in the paediatric population. The lack of ossification of the posterior arch of the spine in normal infants and the presence of a bony defect in patients with spina bifida permit sonographic examination.
MRI
MRI is useful in visualizing the conus medullaris, assessing the thickness of the filum terminale, identifying traction lesions, and evaluating associated bony dysraphisms.
Prone imaging may be useful in patients who have undergone tethered cord surgery or in those in whom clinical suspicion is high while supine MRI imaging demonstrated no abnormalities 6. Prone MRI imaging is however of little value when supine MRI has demonstrated a causative abnormality.
Treatment and prognosis
Untreated, tethered cord syndrome has a progressive course. Surgical release, in selected patients, can stabilize or improve function 3.
History and etymology
Tethered cord syndrome was coined in 1976 by Hoffman and colleagues, who described a series of patients with neurologic symptoms associated with low conus and/or thick filum identified on iophenyldatemyelography4. Previously, this description was termed the filum terminale syndrome16. Over the years, use of the term expanded beyond the tight filum and now many of the underlying dysraphic conditions excluded by Hoffman and colleagues are considered typical etiologies under the umbrella of tethered cord syndrome 15.
-</ul><p>The condition typically presents in children but occasionally goes undiagnosed until or is acquired in adulthood.</p><h4>Pathology</h4><p>The spinal column develops at a greater rate than the spinal cord during fetal development, and abnormal attachments lead to abnormal stretching of the spinal cord.</p><h5>Etiology</h5><p>Tethered cord syndrome can result from a variety of spinal dysraphisms, <sup>7</sup> such as <a href="/articles/myelomeningocele-1">myelomeningocele</a>, tumors, and other <a href="/articles/spinal-dysraphism-2">spinal dysraphisms</a> <sup>7</sup>.</p><h5>Classification</h5><p>Classifications of etiologies as "primary" or "secondary" tethered cord syndrome are heterogeneous and conflicting in the literature. For instance, primary tethered cord syndrome may refer to all congenital causes in general, closed <a href="/articles/spinal-dysraphism-2">spinal dysraphisms</a> as a group, or <a href="/articles/tight-filum-terminale-syndrome">tight filum terminale</a> in particular <sup>3,8,9</sup>. Without a consensus nomenclature, this classification is best avoided.</p><h4>Radiographic features</h4><p>Most commonly, the conus medullaris terminates in a low position below the level of the L2 vertebral body <sup>1</sup>. However, tethered cord syndrome is possible in the setting of a normal conus position <sup>5,7</sup>.</p><p>Additional imaging features depend on the etiology, which are described separately:</p><ul><li><a href="/articles/tight-filum-terminale-syndrome">tight filum terminale</a></li></ul><p>Commonly associated </p><h5>Ultrasound </h5><p>Ultrasound may be a useful screening exam and may be of use in the paediatric population. The lack of ossification of the posterior arch of the spine in normal infants and the presence of a bony defect in patients with <a href="/articles/spina-bifida">spina bifida</a> permit sonographic examination.</p><h5>MRI</h5><p>MRI is useful in visualizing the conus medullaris, assessing the thickness of the filum terminale, identifying traction lesions, and evaluating associated bony dysraphisms.</p><p>Prone imaging may be useful in patients who have undergone tethered cord surgery or in those in whom clinical suspicion is high while supine MRI imaging demonstrated no abnormalities <sup>6</sup>. Prone MRI imaging is however of little value when supine MRI has demonstrated a causative abnormality.</p><h4>Treatment and prognosis</h4><p>Untreated, tethered cord syndrome has a progressive course. Surgical release, in selected patients, can stabilize or improve function <sup>3</sup>. </p>- +</ul><p>The condition typically presents in children but occasionally goes undiagnosed until or is acquired in adulthood.</p><h4>Pathology</h4><p>As the <a href="/articles/spinal-anatomy-1">spinal column</a> grows faster than the cord, tethering lesions cause progressive stretching of the spinal cord. Abnormal traction leads to chronic ischemic changes and neuronal dysfunction.</p><h5>Etiology</h5><p>Tethered cord syndrome is associated with most of the major types of <a href="/articles/spinal-dysraphism-2">spinal dysraphism</a>, except isolated bifid vertebrae (<a href="/articles/spina-bifida-occulta">spina bifida occulta</a>) and <a href="/articles/spinal-neurenteric-cysts">neurenteric cysts</a> <sup>7,</sup><sup>11</sup>. Moreover, as open spinal dysraphism (mostly <a href="/articles/myelomeningocele-1">myelomeningocele</a>) must be repaired in the neonatal period, those patients with this history who develop tethered cord syndrome do so years later due to adhesions rather than the dysraphism itself <sup>11</sup>.</p><p>Thus, the most common causes of tethered cord syndrome are closed spinal dysraphisms: <a href="/articles/spinal-lipomas">spinal lipomas</a> (<a href="/articles/lipomyelomeningocele-1">lipomyelomeningocele</a>, <a href="/articles/conus-lipoma">conus lipoma</a>, and <a href="/articles/lipoma-of-the-filum-terminale">filar lipoma</a>) and <a href="/articles/tight-filum-terminale-syndrome">tight filum terminale</a> (with or without filar lipoma) <sup>10,12-14</sup>. Other causes include <a href="/articles/arachnoiditis">arachnoid</a> adhesions (due to trauma/surgery or infection/inflammation), split cord malformation (<a href="/articles/diastematomyelia">diastematomyelia </a>and <a href="/articles/diplomyelia">diplomyelia</a>), <a href="/articles/dorsal-dermal-sinus">dermal sinus tracts</a>, and <a href="/articles/spinal-dermoid-cyst">dermoid</a>/epidermoid tumors <sup>10,14</sup>.</p><h5>Classification</h5><p>Classifications of etiologies as "primary" or "secondary" tethered cord syndrome are heterogeneous and conflicting in the literature. For instance, primary tethered cord syndrome may refer to all congenital causes in general, closed <a href="/articles/spinal-dysraphism-2">spinal dysraphisms</a> as a group, or <a href="/articles/tight-filum-terminale-syndrome">tight filum terminale</a> in particular <sup>3,8,9,15</sup>. Without a consensus nomenclature, these terms are best avoided.</p><h4>Radiographic features</h4><p>Most commonly, the conus medullaris terminates in a low position below the level of the L2 vertebral body <sup>1</sup>. However, tethered cord syndrome is possible in the setting of a normal conus position <sup>5,7</sup>.</p><p>Additional imaging features depend on the etiology, which are described separately:</p><ul><li><a href="/articles/tight-filum-terminale-syndrome">tight filum terminale</a></li></ul><p>Commonly associated </p><h5>Ultrasound </h5><p>Ultrasound may be a useful screening exam and may be of use in the paediatric population. The lack of ossification of the posterior arch of the spine in normal infants and the presence of a bony defect in patients with <a href="/articles/spina-bifida">spina bifida</a> permit sonographic examination.</p><h5>MRI</h5><p>MRI is useful in visualizing the conus medullaris, assessing the thickness of the filum terminale, identifying traction lesions, and evaluating associated bony dysraphisms.</p><p>Prone imaging may be useful in patients who have undergone tethered cord surgery or in those in whom clinical suspicion is high while supine MRI imaging demonstrated no abnormalities <sup>6</sup>. Prone MRI imaging is however of little value when supine MRI has demonstrated a causative abnormality.</p><h4>Treatment and prognosis</h4><p>Untreated, tethered cord syndrome has a progressive course. Surgical release, in selected patients, can stabilize or improve function <sup>3</sup>. </p><h4>History and etymology</h4><p>Tethered cord syndrome was coined in 1976 by <strong>Hoffman</strong> and colleagues, who described a series of patients with neurologic symptoms associated with low conus and/or thick filum identified on <a href="/articles/iophendylate">iophenyldate</a> <a href="/articles/myelography">myelography</a> <sup>4</sup>. Previously, this description was termed the <a title="Tight filum terminale syndrome" href="/articles/tight-filum-terminale-syndrome">filum terminale syndrome</a> <sup>16</sup>. Over the years, use of the term expanded beyond the tight filum and now many of the underlying dysraphic conditions excluded by Hoffman and colleagues are considered typical etiologies under the umbrella of tethered cord syndrome <sup>15</sup>.</p>
References changed:
- 10. Shang A, Yang C, Cheng C et al. Microsurgical Efficacy in 326 Children with Tethered Cord Syndrome: A Retrospective Analysis. Neural Regen Res. 2019;14(1):149. <a href="https://doi.org/10.4103/1673-5374.243720">doi:10.4103/1673-5374.243720</a>
- 11. Lew S & Kothbauer K. Tethered Cord Syndrome: An Updated Review. Pediatr Neurosurg. 2007;43(3):236-48. <a href="https://doi.org/10.1159/000098836">doi:10.1159/000098836</a>
- 12. Hüttmann S, Krauss J, Collmann H, Sörensen N, Roosen K. Surgical Management of Tethered Spinal Cord in Adults: Report of 54 Cases. J Neurosurg Spine. 2001;95(2):173-8. <a href="https://doi.org/10.3171/spi.2001.95.2.0173">doi:10.3171/spi.2001.95.2.0173</a>
- 13. van Leeuwen R, Notermans N, Vandertop W. Surgery in Adults with Tethered Cord Syndrome: Outcome Study with Independent Clinical Review. J Neurosurg Spine. 2001;94(2):205-9. <a href="https://doi.org/10.3171/spi.2001.94.2.0205">doi:10.3171/spi.2001.94.2.0205</a>
- 14. Koyanagi I, Iwasaki Y, Hida K, Abe H, Isu T, Akino M. Surgical Treatment Supposed Natural History of the Tethered Cord with Occult Spinal Dysraphism. Childs Nerv Syst. 1997;13(5):268-74. <a href="https://doi.org/10.1007/s003810050081">doi:10.1007/s003810050081</a>
- 15. Agarwalla P, Dunn I, Scott R, Smith E. Tethered Cord Syndrome. Neurosurg Clin N Am. 2007;18(3):531-47. <a href="https://doi.org/10.1016/j.nec.2007.04.001">doi:10.1016/j.nec.2007.04.001</a>
- 16. Garceau G. The Filum Terminale Syndrome (The Cord-Traction Syndrome). J Bone Joint Surg Am. 1953;35-A(3):711-6. <a href="https://www.ncbi.nlm.nih.gov/pubmed/13069561">PMID 13069561</a>
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