What is tethered cord syndrome?
Tethered spinal cord syndrome (TCS) refers a group of neurological disorders that cause the pulling of the spinal cord at the base of spinal canal. It is also termed as occult dysraphism sequence. Many different forms of TCS include1:
- Dermal sinus tracts
- Tight filum terminale
- Split cord malformation
All of the above listed forms have a common characteristic of pulling the spinal cord at the base or at the lower end of spinal canal. Normally, the spinal cord is stuck loosely in the spinal canal, can grow freely in both up and downward directions, moreover, it can also be stretched. While in the case of tethered spinal cord, it is held tightly at the base or at some other point in the spinal canal. In children, this tethered cord can stretch the spinal cord forcefully during the process of its growth. While in the case of adults, stretching of the spinal cord occurs during the course of normal activity, causing progressive spinal cord injury if untreated. The diagnosis of adult type of TCS is necessary as the complications of this syndrome can easily be reversed by releasing the involved cord2.
Neurological spine surgeon Dr. Robert Bray gives an excellent explanation about TCS.
Following are some possible causes of TCS3:
- Disturbed and improper growth of neural tube during fetal development
- Presence of spina bifida
- After spinal cord trauma
- Syringomyelia- cysts in spinal cord
Clinical features of TCS
Tethered cord symptoms in children
In children, this disorder may present with4,5:
- Skin lesions are present in about 80-100% children with this disorder, for example, different types of skin manifestations like hairy patches, dimples, or fatty tumors on lower back
- Weakness of both lower limbs
- Deformities of spine and feet
- Backward or lateral curvature of spine
- Pain in lower back
- Urinary incontinence
- Urinary retention
Sometimes, TCS remains undiagnosed until adulthood, when complaints regarding sensations, motor activities, bowel and bladder control emerge. This late appearance of tethered cord symptoms correlates with the degree of stretch of the spinal cord with passage of time.
Symptoms of tethered cord syndrome in adults
In adults, this disorder may present with 4,5:
- Skin lesions are present in almost 50% of adults with this spinal abnormality, for example, hairy patches, dimples, or fatty tumors on lower back
- Unbearable pain in the lower back with radiation into legs, groin and perineum.
- Weakness of muscle and loss of sensations of touch, vibration, temperature, pain and proprioception
- Urinary incontinence, retention, frequency, urgency, feeling of incomplete voiding.
- Rectal prolapsed and atonic pelvic floor in females
- Bowel retention
- Bowel control issues
- Mixed upper and lower motor neuron findings like amyotrophy, hypereflexia and up-going planter
- Chronic recurrent kidney infections and stones
The diagnosis of this abnormality depends upon clinical and radiological criteria. Clinically, patients with such a disorder can present with diffused or localized severe lower back pain, lower limbs weakness with loss of different sensations, muscle atrophy and urinary incontinence. In the past, positive-contrast myelography and intrathecal-contrast computerized tomography were used to diagnose this condition.
At present, MR Imaging is considered the procedure of choice to diagnose the tethered spinal cord. Imaging in patients with this condition shows low conus meddullaris, that is, below the level of the second lumber vertebra and thickened filum terminale of more than 2 mm. MRI is very important for visualizing conus meddullaris, estimating the thickness of filum terminale, identifying the traction lesions and getting information about associated bony dysraphisms.
Prone MRI is helpful in patients in whom the clinical suspicion of TCS is very high but the supine MRI showed no abnormality. There is not much value of prone MRI when supine MRI has showed the defect6. Tethered cord surgery is the definite treatment of choice for TCS. Early diagnosis and surgery can prevent the complications of the condition. Tethered cord surgery is performed to free the spinal cord. Other treatment options are symptomatic and supportive. These include6:
- Use of pain-killers like NSAIDS and opiates to relieve the pain
- Use of antidepressants for severe pain and discomfort
- Muscle relaxing exercises
- Treatment of urinary tract infection
Video about TCS Surgery and an interview with a patient on what he went through.
Although this syndrome progresses with time its prognosis depends upon early diagnosis and surgical treatment. With surgical treatment patients with TCS have a normal life expectancy. In advanced cases most of the neurological and sensory deficits are irreversible.
- Hertzler DA, DePowell JJ, Stevenson CB, Mangano FT. Tethered cord syndrome: a review of the literature from embryology to adult presentation. Neurosurg Focus 2010;29(1):E1. doi: 10.3171/2010.3.FOCUS1079.
- Yamada S, Lonser RR. Adult tethered cord syndrome. J spinal Disord 2000;13(4):319-23.
- Agarwalla PK, Dunn IF, Scott RM, Smith ER. Tethered cord syndrome. Neurosur Clin N Am 2007;18(3):531-47.
- Yamada S, Siddiqi J, Won DJ, Kido DK, Hadden A, Spitalieri J, et al. Symptomatic protocols for adult tethered cord syndrome. Neurol Res 2004;26(7):741-4.
- Pang D, Wilberger JE Jr. Tethered cord syndrome in adults. J Neurosurg 1982;57(1):32-47.
- Ratliff J, Mohaney PS, Kline DG. Tethered cord syndrome in adults. South Med J 1999;92(12):1199-203.