Intermittent Back and Leg Pain with Numbness
Am Fam Physician. 2008 Oct 1;78(7):869-870.
A 62-year-old man presented with a long history of intermittent low back pain and numbness. The pain was associated with lower extremity weakness and posterior leg numbness that occurred primarily with back stretching movements. He denied a history of trauma or a family history of major disease. The day of presentation, he had two episodes, each lasting a few minutes. The first occurred while he reached for a high object, and the second occurred as he got out of his car. The physical examination revealed a small dimple with hyperpigmented, hairy skin on the lower back (Figure 1). The neurologic examination was essentially unremarkable.
Based on the patient's history and physical examination, which one of the following is the most likely diagnosis?
A. Enterogenous cyst.
B. Herniated lumbar disc.
C. Spinal stenosis.
E. Tethered spinal cord syndrome.
The answer is E: tethered spinal cord syndrome. The patient's history and physical examination findings are classic for this syndrome. Magnetic resonance imaging (MRI) showing a low-lying tethered spinal cord ending at L3–4 with an associated neural tube defect (Figure 2) confirmed the diagnosis. Tethered spinal cord syndrome is a neurologic disorder caused by tissue attachments that stretch the spinal cord and limit its movement.1,2 It is associated with a number of congenital and acquired anomalies2,3 (Table 1). Other causes include dermal sinus tract, diastematomyelia (split spinal cord), trauma with scar tissue, and intradural dermoid cyst.3,4
Table 1. Selected Conditions Associated with Tethered Spinal Cord Syndrome
Selected Conditions Associated with Tethered Spinal Cord Syndrome
Abnormal congenital division of the spinal cord by a bony spicule or fibrous band protruding from one or two vertebra; each half is surrounded by a dural sac
Fibrofatty terminal filum
Remnant of incomplete neural tube closure; caused by a failure of the surface ectoderm and dermal elements to separate from the neuroectoderm
Intradural dermoid cyst
Slow growing, congenital, benign tumors of the central nervous system
Low-lying conus medullaris
Failure of the conus medullaris to ascend may lead to tethered spinal cord syndrome; this ascension seems to occur during fetal development
Incomplete closure of the embryonic neural tube leads to an incompletely formed spinal cord with unfused posterior vertebral structures
Meningocele is protrusion of the meninges through the gap in the spine; myelomeningocele is the protrusion of the spinal cord and the nerve roots from the gap in the spine; spina bifida occulta is the mildest form, and the spinal cord is often unaffected
Spinal cord lipoma
Rare fatty-tissue tumors; mostly from a neural tube defect
Trauma with scar tissue
Symptoms may include low back pain, leg weakness, and numbness. In advanced disease, leg pain and loss of bladder and bowel control may occur. Examination may reveal hemangiomas, a tuft of hair, a dimple, fatty tissue, or a “tail.”5 Early surgery is recommended in children to prevent neurologic deterioration.1–5 In adults, surgery to detether the spinal cord can reduce complications. Other treatments are symptomatic and supportive, including pain control and physical therapy.6,7 MRI can confirm the diagnosis.
Enterogenous cysts of the central nervous system usually occur in the spinal canal, especially in the lower cervical and upper thoracic regions. They are benign epithelium-lined cysts. The cysts are often associated with developmental defects of the overlying skin or vertebral bodies and can cause spinal cord compression.8
Patients with a herniated disc may have sensory or motor dysfunction corresponding to the level of the nerve root compressed by the herniated disc. Diagnosis can be confirmed with MRI.9
Spinal stenosis is a narrowing of the spinal canal, lateral recess, or neural foramen with neurogenic claudication or pseudo-claudication.9
Syringomyelia includes cysts within the spinal cord that may cause pain, weakness, and stiffness in the back, shoulders, arms, or legs. MRI confirms the diagnosis.10
1. Yamada S, et al. What is the true tethered cord syndrome? Childs Nerv Syst. 2007;23(4):371–375.
2. Warder DE. Tethered cord syndrome and occult spinal dysraphism. Neurosurg Focus. 2001;10(1):e1.
3. Steinbok P, et al. Occult tethered cord syndrome. J Neurosurg. 2006;104(5 suppl):309–313.
4. Terai T, et al. Adult onset tethered cord syndrome associated with intradural dermoid cyst. Spinal Cord. 2006;44(4):260–262.
5. Tethered spinal cord. http://www.neurosurgerytoday.org/what/patient_e/tethered.asp. Accessed June 10, 2007.
6. Iskandar BJ, et al. Congenital tethered spinal cord syndrome in adults. Neurosurg Focus. 2001;10(1):e7
7. Selden NR. Occult tethered cord syndrome. J Neurosurg. 2006;104(5 suppl):302–304.
8. Russell DS, et al. Pathology of Tumours of the Nervous System. 5th ed. Baltimore, Md.: Williams & Wilkins; 1989:704–706, 721–725.
9. Branch WT, ed. Office Practice of Medicine. 4th ed. Philadelphia, Pa.: Saunders; 2002:785.
10. Mason DE. Back pain in children. Pediatr Ann. 1999;28(12):727–738.
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