MENINGOCELE:

Q. What is a meningocele?

A meningocele is a closed spinal dysraphism consisting of a CSF-filled sac that herniates through a posterior bony defect, but contains no neural tissue. The spinal cord remains within the canal, and the sac is covered by skin. It results from failure of dorsal vertebral arch formation with intact neural tube closure.

Q. How does a child with meningocele present clinically?

Most present with a midline, skin-covered swelling in the lumbosacral region. Neurological examination is typically normal because neural elements do not herniate into the sac. However, some children may have associated anomalies such as tethered cord, split cord malformation, or dermal sinus, so subtle motor, bladder, or foot abnormalities may coexist.

Q. How is a meningocele managed?

MRI is performed to confirm absence of neural tissue in the sac and to evaluate associated dysraphism. Surgical treatment involves simple excision of the meningocele sac and watertight dural closure. Because the cord is not included, neurological risk is low. Associated anomalies (e.g., tethered cord, dermal sinus, SCM) must be identified and addressed accordingly.

DERMAL SINUS TRACT:

Q. What is a dermal sinus tract?

A dermal sinus tract is a congenital epithelial-lined channel extending from the skin surface toward the underlying neural elements due to failure of complete dysjunction between surface ectoderm and neural ectoderm during primary neurulation. It may terminate in subcutaneous tissue, dura, thecal sac, or even attach to the spinal cord, and frequently coexist with dermoid or epidermoid inclusion tumors.

Q. How does a dermal sinus tract present clinically?

Clinically, it appears as a midline skin dimple or pit, often with hair, discharge, or recurrent local infection. Neurological findings may result from tethered cord or inclusion tumors. Recurrent meningitis or abscess is a classic presentation because the tract provides a direct path for infection from the skin to the thecal sac.

Q. How is a dermal sinus tract managed?

Management is complete surgical excision of the tract using microsurgical techniques with intradural exploration to remove any associated dermoid/epidermoid tumor and to detether the cord. Early surgery is recommended even if asymptomatic because of the high risk of meningitis and progressive neurological decline.

FILAR LIPOMA:

Q. What is a filar lipoma?

A filar lipoma is a fatty infiltration of the filum terminale, caused by abnormal differentiation of caudal mesenchyme during secondary neurulation. It may tether the conus and restrict its ascent, often associated with a low-lying conus.

Q. How does a filar lipoma present clinically?

Most are asymptomatic early in life but may later present with tethered cord symptoms such as back pain, gait issues, foot deformities, scoliosis, or bladder dysfunction. Many are discovered incidentally during MRI for other reasons.

Q. How is a filar lipoma managed?

Treatment is surgical sectioning of the filum terminale when symptomatic or when imaging demonstrates a low conus with evidence of tethering. Surgery is straightforward and carries low neurological risk because the filum contains no functional neural elements.

TIGHT FILUM TERMINALE:

Q. What is a tight filum terminale?

A tight filum terminale is an abnormally thickened, inelastic filum that tethers the conus medullaris, typically defined as a filum >2 mm in diameter. It may or may not contain fat and results from disordered canalization during secondary neurulation.

Q. How does a tight filum present clinically?

Children may present with tethered cord symptoms (leg pain, gait disturbance, urinary symptoms, or foot deformities) despite a skin-covered back. MRI often shows a low-lying conus (below L2–L3) and a thickened filum without a large lipomatous mass.

Q. How is a tight filum managed?

Management is simple filum sectioning through a small laminotomy. Intraoperative stimulation is used to confirm the structure is non-functional. Sectioning releases the tethering and prevents progression of neurological and urological deficits.

TERMINAL MYELOCYSTOCELE:

Q. What is a terminal myelocystocele?

A terminal myelocystocele is a closed, skin-covered spinal dysraphism resulting from a failure of secondary neurulation, in which the distal spinal cord balloons outward into a CSF-filled terminal cyst that extends dorsally through a posterior bony defect while maintaining continuity with a low-lying conus. It characteristically shows a “trumpet-like” flaring of the distal spinal cord on MRI.

Q. How does a child with terminal myelocystocele present clinically?

Children typically present at birth with a lumbosacral midline mass covered with normal or stretched skin. The conus is low and tethered, so progressive neurological or urological symptoms can appear with growth (leg weakness, gait disturbance, foot deformities, or neurogenic bladder). Associated anomalies are common, including anorectal malformations and urogenital anomalies.

Q. How is a terminal myelocystocele managed surgically?

MRI defines the anatomy. Surgery involves untethering of the cord, decompression of the terminal cyst, and reconstruction of the distal neural tube. The cyst is opened, the distended terminal cord is reduced and contoured, and a generous duraplasty is performed to prevent further tethering. The wound is closed in layered fashion. Early surgery is favored to avoid progression of neurological deficits.