Ultrasound of the Neonatal Spine - Paranormal Zone & Haunting Dimensions

Make sure that the child is warm and close to his mother or father so you can scan the spine with less movements ,less kicking and crying. Remember, a warm, quiet relaxed baby leads to a quicker easier scan with more accurate results.

Normal Spine , Sag ital ; Conus Medullaris dont pass L2.

– It is the premier tool for screening for most suspected neonatal spinal abnormalities from the first few hours of life.

– It requires no ionizing radiation or sedation. Generally, ultrasound can be used as a stand alone tool to investigate for spinabifida occulta, cord tethering, masses, infection and the degree of clinically obvious abnormalities.

– You can start with the sacrum toward the T12. and make sure to look also for lipoma, cysts, and other masses.

Transv scan at the tip of the conus medullaris.
Indications

Posterior mid-line cysts/masses
Mid-line skin dimples – often called a ‘Sacra Pit’.

– Babies with tiny mid-line skin defects low in the sacro-coccygeal region at the upper buttock cleft, will generally be normal.

– Larger or higher clefts are more likely

Isolated simple sacral dimples in the asymptomatic healthy neonatal population are common. The risk of underlying significant spinal malformations in this patient population is exceedingly low.

associated with spinal abnormalities.

Tufts of hair
visible haemangioma / skin discoloration
Anal atresia / stenosis
Guidance for lumbar puncture
Post injury / trauma
Post surgical – follow up or complication
Infection / abscess

Limitations

– Caution needs to be exercised with open (or near-open) neural tube defects. If scanning is required in these circumstances, sterile technique should be observed, ideally with a sterile gel stand-off so minimal pressure is required. Sterile water/saline may be appropriate rather than gel. This should be discussed with the managing physician.

– Generally, if available, MRI is the modality of choice for open neural tube defects, including small CSF leaks.

Equipment Selection

A high frequency, linear array transducer. Minimum 8Mhz. Ideally a large footprint to offer more length of the image field.
You may also require a smaller footprint, higher frequency probe to assess fistula or for procedural needle guidance.
‘Panorama’ function is useful to demonstrate the relationship of anatomy/pathology.

Room / equipment preparation

Warm room.
Warm gel.
Warm hands.
Dim lighting
Bribery: a soothing parent or assistant, food, pacifier (dummy). Glycerin (glucose syrup) can be useful to dip the pacifier, or a maternal finger, in to encourage quiet sucking..

Patient position

Prone, head, slightly higher than the feet to better fill the lower csf space.
A rolled towel (or similar) under the baby’s abdomen to slightly widen the posterior inter-spinous spaces.

– If using ultrasound to guide a spinal tap, the more erect you are able to position the baby, the more csf will be visible, avoiding a ‘dry-tap’.

Scanning Technique

– Begin with a survey scan (this will take less than a minute) followed by a detailed assessment.

Firstly in transverse, sweep from the mid thoracic region to the sacro-coccygeal region.

– Are the posterior neural arches, paired and uniform.

– Are there any obvious, gross pathologies.

Next, a sagittal sweep from one side to the other.

– Depending on your transducer footprint as to how many passes you require to cover the anatomy.

– Are there any obvious, gross pathologies.

Is the cord and CSF space uniform in shape?

– Follow the cord along in transverse assessing the shape and central position.

– Any variation in position or shape of the cord is suggestive of mass effect and scrutiny for the cause is needed.

– Similarly the CSF space should be uniform.

Conus Medullaris is at L5. up normal

It must not pass L2. Some Dr take the normal if it was slightly pass L2 but not passing the middle point of L3.

Just passing L2.

Identify the 12th rib, and thus T12 and count down. There are two primary methods to determine the level of conus.

identify the lumbo-sacral junction and count up from L5.

Normal conus position is: No lower than the top of L3 in a term infant or the bottom L3 in a pre-term infant.

– Be cautious of variation in the number of lumbar vertebrae.

* If the level cannot be accurately determined, a radio-opaque marker (ball bearing or similar) may by fixed to the skin over conus, and a plain X-ray performed. this should only be performed if there is sufficient clinical concern. Ensure the baby is flat when the marker is applied to eliminate error from relative movement of the skin-spine

Normal Filum terminal. less than 2 mm.
It should appear as thin closely related parallel lines extending from conus to the lowest reaches of the thecal space (approximately S2).

– Filum is approximately 2 mm in diameter.

– A filar cyst (ventriclus terminalis) is an commonly seen anatomical variant. It will be seen as a focal fusiform thickening of filum, usually close to conus.

– The nerve roots comprising cauda equina should lie in the dependent portion of the thecal sac.
sag view of Cauda Equina
TRV , View of cauda equina terminal
– Should see gentle oscillating movements with the baby’s cardiac pulsations and respiration.

– Symmetry. Look for asymmetry indicative of pathology (space occupying mass or unilateral abnormality)

Normal Conus .

Examine the bony anatomy

– Particular attention should be paid to the integrity the posterior neural arches in the transverse plane.

– Check the vertebral bodies for alignment, shape and symmetry in both transverse and sagittal planes.

Examine the Dimple

– If there is a dimple or skin defect, this should be carefully examined with a high frequency probe to look for a skin – thecal sac fistula.

– Use minimal pressure so as not to compress and thus obscure a fistula tract.

– An anatomical variant is a thin hypoechoic fibrous band from the dimple to the coccyx. This is of no clinical significance. Most true fitsulae will be higher than the coccygeal region.

– If CSF is leaking, an MRI should be performed.

Pathology

Spina bifida and its sequelae.
Low conus medullaris – cord tethering
Arachnoid cysts / pseudomenigoceles
Intra-thecal lipomata

Remember, a warm, quiet relaxed baby leads to a quicker easier scan with more accurate results.

Skin – thecal sac fistula
Haemangioma
haematoma
Complicated CSF ( infection or bleeding)
Vertebral agenesis, malformation or malalignment

Take a scan view for

T12 – S2 posterior bony arches in transverse.
Transverse cord, conus and nerve roots.
Longitudinal distal cord with conus and labelled vertebral numbers (T12, L1, L2 etc).
Longitudinal at the ‘dimple’.