Spine Variants and Pathology Flashcards
Where are filar cysts located?
Within midline terminale, inferior to the conus
T or F? Filar cysts are a normal variant?
True
Where are ventricular terminalis located?
Transition from tip of the conus to origin of filum terminale
What are ventricular terminalis also known as?
5th ventricle or persistent terminal ventricle
What is the ventricular terminalis?
Widening of the distal central canal
What are the two normal variants of the spine?
- Filar cyst
- Ventricular terminalis
By what week gestation is the neural tube formed?
8 weeks
The neural tube is formed by the closure of the?
Neural plate
Spinal dysraphism occurs when?
The neural plate fails to fuse completely
What is another term for OSD and CSD?
OSD - spina bifida aperta
CSD - spina bifida occulta
What is the difference between OSD and CSD?
OSP - Neural tissue communicates with the outside through a defect that does NOT include skin or tissue covering
CSD - Skin covered abnormality - usually seen as a dimple or tuft of hair in the lower back
What is a meningocele?
Protrusion of meninges without neural tissue (covered by a thin layer of skin)
What is a myelomeningocele?
Protrusion of meninges and neural tissue through a defect
What is a myelocele?
Protrusion of neural tissue without skin or meninges - shows as “flush” with the skin
How does spina bifida occulta present?
As a tuft of hair
What abnormality is a flat plate of neural tissue flush with the skin surface?
Myelocele
What 2 abnormalities are known as a herniation thru a defect in the dura mater?
- Myelomeningocele
- Myelocele
Is a meningocele classified as an open or closed spinal dysraphism?
Closed
Open and closed spina bifida are typically all associated with?
A tethered cord
What is the definition of a tethered cord?
Low-lying cord with thickened filum terminale (< 2mm)
What is almost ALWAYS associated with dysraphic spinal anomalies?
Tethered cord
What are 3 complications of OPEN spinal dysraphism?
- Decreased limb function and paralysis
- Bladder and bowel dysfunction
- Hydrocephalus
SF of open spinal dysraphism?
- Anechoic mass continuous with spinal cord
- Loss of normal conus
SF of a tethered cord?
- Lack of movement of filum terminale and nerve roots
- Spinal cord low (conus terminates at L3 or after)
- Conus will be abnormally elongated and lack normal tapering
- Thickened filum terminale (>2mm)
What is another name for diastomyelia?
Split cord malformation
What is known as a longitudinal split of the spinal cord into 2 hemicords?
Diastomyelia
Where in the spine does split cord normally occur?
Thoracolumbar region
In what plane of imaging is a split cord diagnosed?
Transverse orientation
What anomalies are associated with diastomyelia?
- Tethered cord
- Scoliosis
- Clubfoot
- Vertebral anomalies
- Dilation of central canal (hydromelia)
What is known as a thin epithelial-lined tract that courses from the skin towards the spinal canal representing a focal disruption on the fusion of the spinal canal?
Dorsal dermal sinus (DDS)
Where is DDS most common?
Lumbosacral region
How do DDS clinically appear?
As deep midline dimples or pits
What are patients at risk for developing with DDS?
Meningitis
SF of DDS?
Midline tract from spinal cord to skin (most likely in the area of a skin marker)
An abnormal focus of echogenicity within the canal of a DDS is visualized. What may be the most likely diagnosis?
Dermoid
What is the most common reason an infant is referred for a spinal ultrasound?
Sacral dimple
Sacral dimples may appear as one of two things, what are they?
- Blind ending
- As a pilonidal sinus - tract that leads to the coccyx
Does a pilonidal sinus communicate with the spinal canal?
NO - do not confuse for DDS
What are the three types of spinal lipomas?
- Lipomyocele/lipomyelomeningocele
- Intradural lipoma
- Lipoma of the filum terminale
What is the most common spinal lipoma?
Lipomyocele/lipomyelomeningocele
What is the difference between a lipomyocele and lipomyelomeningocele?
Lipomyocele - Stays within spinal canal
Lipomyelomeningocele - Enlarged subarachnoid space and a fatty mass extending through posterior defect
Why are intradural lipomas and lipomas of the filum terminale different from lipomyocele/lipomyelomeningocele?
The first two DO NOT contain an associated subcutaneous mass and may or may not have a tethered cord
What is known as an abnormal dilatation of the terminal ventricle that communicates with the central spinal cord but does not communicate with the subarachnoid space?
Terminal myelocystocele
SF of terminal myelocystocele?
- Large, skin-covered, fluid filled mass in lumbar region
- Widened central canal of spinal cord with DIRECT communication with the cyst
- Hydromelia
What are the 3 vertebral anomalies?
- Block vertebrae - incomplete separation of vertebral bodies
- Hemi-vertebrae - lack of formation of one vertebral body
- Butterfly vertebrae - failure of fusion of the lateral halves of the vertebrae
What is the most common type of germ cell tumour occurring in the neonatal period?
Sacrococcygeal teratoma
