A syndrome resulting from abnormal development of the filum terminale resulting in persistent anchoring of the spinal cord conus medullaris at or below the L2 level leading to progressive neural damage with difficulties for walking and bladder and bowel control problems.
Sporadic, occurs as part of inherited syndromes but has not been described in isolation.
Normal regression of the distal embryonic spinal cord produces a thread-like filum terminale attached to the coccyx when differential growth of the conus medullaris occurs in the child. When this regression is abnormal, it results in a thick rope-like filum that anchors the conus at or below L2 level instead of the usual final L1 level. Usually associated with spina bifida. This may coexist with diastematomyelia and Arnold-Chiari malformation. Neurological signs may develop as a consequence of increased tension on the cord compromising blood supply, particularly with flexion and extension. Treatment requires the release of the spinal cord via a posterior route (mini-laminectomy) to resect the lipoma, cut the filum terminale, or free scar adhesions.
Clinical signs confirmed by CT or MRI scan.
May be asymptomatic or present with progressive neurological dysfunction of the lower cord. Asymmetric leg growth, talipes cavus, muscle wasting. Bladder dysfunction, progressive scoliosis. Diffuse pain. Midline skin lesion is usually observed in 70% of patients affected. Hyperpigmentation, hemangioma, lipoma dermal pit are frequent other physical characteristics of this syndrome.
Precautions before anesthesia
Routine preoperative assessments. In the presence of a significant scoliosis, respiratory evaluation, including spirometry, should be obtained.
Usual considerations for prone position. The use of intraoperative neuromonitoring for tethered cord release contributes significantly to maintain functional integrity and is highly recommended. May require catheterization; care with padding if bladder dysfunction or scoliosis is present. Regional anesthesia is relatively contraindicated; however, its indication must be assessed carefully for each patient because of the spina bifida often associated.
There are no specific implications with this condition.
Other condition to be considered
☞Diastematomyelia: Spinal dysraphism characterized by the presence of a median fibrous or bony spur, which passes through the spinal canal in the sagittal plane. Characterized by pain, weakness of legs, and incontinence. Surgical repair during infancy recommended.
GM: Spina bifida, tethered cord, and regional anesthesia. Anaesthesia
R: Tetherd cord syndrome, in Behrman
et al (eds): Nelson Textbook of Pediatrics. 14th ed. Philadelphia, WB Saunders, 1992, p 1536.