Tethered Cord Syndrome in Children: A Review

Cuong J. Bui, M.D.; Shane Tubbs, M.S., P.A.-C., PH.D.; Jerry Oakes, M.D.

Disclosures

Neurosurg Focus. 2007;23(2):E2 

In This Article

Diagnosis: Clinical Signs/Symptoms and Neuroimaging Findings

Patients with symptomatic TCS can present with a wide variety of signs and symptoms in combination with cutaneous, orthopedic, spinal, anorectal, and urological abnormalities, as well as pain (Table 1). In our experience, the common clinical presentations (Fig. 1 left) include the presence of cutaneous signatures associated with OSD (59%), neurogenic bladder with the development of primary or secondary incontinence or urinary tract infection (18%), leg or foot weakness, numbness and/or spasticity (12%), leg or foot length discrepancy (6%), foot deformity (for example, pes cavus, claw toes), spinal deformities, and nondermatomal back and leg pain (6%).[32] Although pain is a major presenting symptom in the adults with TCS, it is less common and more difficult to identify in the pediatric population because pain often manifests simply as irritability, especially in younger children.

Flow charts. Left and Right: treatment paradigms for patients with a suspected tethered cord.

Cutaneous signatures associated with OSD include lumbosacral hypertrichosis (Fig. 2), cutaneous capillary hemangiomas (nevus) (Fig. 3), dermal sinus tracts (Fig. 4), midline subcuntaneous lipomas, lumbosacral skin appendages (Fig. 5), and so-called cigarette burns or atretic meningocele (Fig. 6). In our experience, cutaneous signatures were seen in 59% of patients with TCS, and the literature suggests that cutaneous anomalies are present in as many as 70% of patients with OSD. Only about 3% of healthy neonates will have such lesions.[34] Patients with TCS often exhibit multiple skin lesions when examined carefully.

Photograph demonstrating hypertrichosis in a 14-yearold girl presenting with leg-length discrepancy.

Photograph of a neonate with a flat capillary hemangioma of the midline lumbar spine.

Photograph showing a dermal sinus tract in a neonate with underlying tethered spinal cord.

Photograph demonstrating a lumbosacral skin appendage in a neonate with imaging findings of a tethered spinal cord.

Photograph of an atretic meningocele cigarette burn–type lesion over the lumbosacral spine of a newborn child. The conus medullaris in this patient was inferiorly displaced.

Urological abnormalities range from obvious incontinence to subtle, subclinical findings seen on urodynamic testing. In the pediatric population, urological abnormalities usually do not become obvious until the child grows out of his/her infant years. They also tend to be more subtle than other clinical findings.[15] The urological presentation can include incontinence, urgency, increased/abnormal frequency, and recurrent urinary tract infections. Urodynamic testing usually confirms a neurogenic bladder in the symptomatic child and can often verify subtle neurogenic bladder dysfunction in young infants suspected of having TCS without any obvious urological dysfunction. We routinely obtain urodynamics studies in all patients with TCS. We find this a very valuable diagnostic tool that can detect subtle or subclinical dysfunction and allows more objective assessment of operative and follow-up risk. Although the test is invasive, young infants generally tolerate it well.

The neurological dysfunction in TCS is unusual, frequently having elements of both upper and lower motor dysfunction. Motor weakness is more prevalent than sensory deficits. Such motor dysfunction is usually asymmetrical. Children can present with delayed gait development, spasticity, hyperreflexia, hyporeflexia, and muscular atrophy. In infants, muscular atrophy can be hidden by subcutaneous fat. Sensory deficits, when present, are usually in the feet or perineum. Children can sometimes present with painless ulcerations of the foot or leg.[30] In our series of 73 patients with TCS, changes in strength, tone, or reflexes were seen in 47 patients (64%).[50]

Orthopedic manifestations include foot deformities (most common), limb-length discrepancies, leg malformations, gluteal asymmetry, and vertebral abnormalities (for example, laminar defects, bifid vertebrae, hemivertebrae, SCM, sacral agenesis, segmentation errors, and scoliosis).[48] Orthopedic deformities of one form or another are found in more than 90% of patients with TCS,[43,48,50] and scoliosis is seen in up to 25%.[15]

It is now well recognized that TCS is often seen with other congenital syndromes. The two most common associations are caudal agenesis (a spectrum of caudal regression abnormalities)[7,42] and anorectal atresia syndromes (OEIS [omphalocele, exstrophy, imperforate anus, spinal defect] syndrome, VATER [vertebrae, anus, trachea, esophagus, and renal] syndrome, and Currarino triad).[4,5,8,24,47] Patients with these syndromes should be screened for OSD and TCS.

Neuroimaging is used to confirm the clinical suspicion of OSD and/or TCS (Table 2).

Ultrasonography. Ultrasonography can be a useful tool in young infants. The advantages are the ability to obtain a dynamic view without having to submit a young child to irradiation or sedation. The disadvantages are that images can be difficult to interpret and the quality is often operator dependent. Identifying the level of the conus medullaris is not difficult in the very young child, but searching for fat or the thickness of the terminal filum can be challenging. The acoustic window in the lumbar spine is usually lost by 4 to 5 months of age.

Plain Radiography. Plain x-ray films of the spine help identify occult spinal abnormalities that may aide in the diagnosis of OCAs. The modality can be a useful tool in observing an associated scoliosis over time. Many of the associated vertebral abnormalities can be seen on routine spine radiographs (Fig. 1, right). This modality is also often used as a preoperative tool in planning surgery.

Magnetic Resonance Imaging. Magnetic resonance imaging is the modality of choice in visualizing the level of the conus medullaris and for identifying a thickened and/ or fatty filum. Sagittal T1- and T2-weighted images are best for localizing the level of the conus, whereas T1- weighted axial MR images are better for identifying fat within the terminal filum and for measuring the diameter of the filum (Fig. 7). We routinely image the entire spinal axis to search for concomitant lesions. Dynamic MR imaging may have some use in understanding pathological conditions of the distal spinal cord,[19,28] although we have found it to be of limited value. This modality can be difficult to undertake in young children, who may require sedation or general anesthesia to obtain quality images.

Sagittal (left) and axial (right) T1-weighted MR images obtained in a 7-year-old child who presented with leg pain and urinary symptoms. Imaging demonstrated a normally positioned spinal cord with fatty terminal filum.

Computed Tomography or CT Myelography. Computed tomography scanning or CT myelography can be used if MR imaging is not available. These modalities permit excellent visualization of the osseous anatomy, and the position of the conus can also be clearly seen. However, CT myelography is invasive and can be difficult to perform in young infants.

Urodynamic Testing. Routine urodynamic tests are performed in our patients suspected of having TCS. In the pediatric patient, being able to determine bladder dysfunction simply based on history or symptoms can be problematic. Palmer and colleagues[33] have used preoperative urodynamic tests to unmask subclinical bladder dysfunction in children presenting with nonurological symptoms indicative of TCS. They reported that such urological dysfunction improved postoperativly in 75% of their patients. Our experience supports this view, and we have found urodynamics to be a very good objective data point to follow pre- and postoperatively.

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