Positioning Notes: L-Spine

Routine Views for L-spine pediatrics- less than 8

AP & Lateral

AP L-spine technique

90 kVp, 10 mAs

AP L-spine centering

• Center @ iliac crest (L4) & down MSP

AP L-spine breathing

Suspended expiration

AP L-spine evaluation criteria

1. area from T12 to superior sacrum should be included

2. intervertebral joints open

3. no rotation

• sacroiliac joints should be equidistant from vertebral column

• symmetric vertebrae, with the spinous processes centered to the bodies

AP L-spine merrill’s SID recommendation

48” (to reduce distortion & open intervertebral disk spaces more)

AP L-spine merrill’s collimation recommendation

8×14 or 8×17

AP L-spine merrill’s recommendation

• recommend PA position

• this would place intervertebral disk spaces at an angle more closely parallel to the divergence of the beam

  • patient dose is also reduced due to decrease abdominal thickness when prone

RPO/LPO L-spine technique

90 kVp, 18 mAs

RPO/LPO L-spine centering

• Center @ L3 (1-1.5” above iliac crest), entering about 2” medial to ASIS

RPO/LPO L-spine - purpose

articular processes & z-joints of side closest to IR are seen

RPO/LPO L-spine- breathing

suspended expiration

RPO/LPO L-spine- evaluation criteria

1. T12- sacrum included, down to SI joint

2. z-joints closest to IR seen

3. vertebral column parallel w/ tabletop so that the T12-L1 & L1-L2 joint spaces remain open

RPO/LPO L-spine- Merrills obliquity

60 degrees (to show L5-S1 z-joints)

Lateral L-spine technique

96 kVp @28 mAs

Lateral l-spine centering

• @ level of L2/L3

Lateral L-spine breathing

suspended expiration

Lateral L-spine evaluation criteria

1. T12- L5/S1

2. open intervertebral disk spaces & foramina of L1-L4

3. no rotation

• posterior margins of each vertebral body should be superimposed

• the crests of the ilium should nearly superimpose each other

4. vertebrae should be aligned down the middle

5. spinous processes in profile

Lateral L-spine: merrills SID recommendation

48” (to reduce magnification of the spine)

Lateral L-spine: Merrills recommendation if the long axis of the vertebral column is not horizontal

• elevate the lower thoracic region w/ a radiolucent support (preferred method)

  • if not using a support,

    • angle tube 8 degree caudad for females

    • 5 degree caudad for males

RH- when a patient arrives for AP & Lateral (only) L-spine imaging, obtain___

all l-spine vertebrae on lateral image (there is no need for an L5-S1 conedown image)

Lateral L5/S1 L-spine technique

96 kVp, @ 45 mAs

Lateral L5/S1 L-spine

• 10×12 LW collimation

• Caudal angle 2” posterior to elevated ASIS & 1.5” inferior to iliac crest

  • females= 8 degree caudad

  • males= 5 degree caudad

• left marker anterior

Lateral L5/S1 L-spine breathing

suspended expiration

Lateral L5/S1 L-spine Evaluation criteria

1. lumbosacral joint should be clearly seen & open

2. all of the 5th lumbar vertebra should be included as well as the upper portion of the sacrum

3. lumbosacral joint centered

4. no rotation (crests of ilia are nearly superimposing each other)

A larger waist on Lateral L5/S1 L-spine may require a slight__

cephalic tube angle

Special Views: L-spine- Anterior Oblique (RAO/LAO)- purpose

articular processes & z-joints of side furthest from IR (scotty dog seen)

Special Views: L-spine- Anterior Oblique (RAO/LAO)- patient position

• prone, turn away from side of interest 45 degrees

  • An oblique position of 60 degrees from the plane of the IR may be needed to show L5/S1 Zygapophyseal joints

  • Adjust body so long axis of patient is parallel to table.

  • In this position the lumbar spine lies in the longitudinal plane that passes 2” lateral to the spinous processes.

Special Views: L-spine: L5/S1 AP axial (ferguson method) purpose

lumbosacral joint & a symmetric image of both sacroiliac joints free of superimposition

(30 degree cephalad for males, 35 degrees for females)

Special Views: Lumbar Spine: AP right & left bending (spinal fusion)- purpose

Used to evaluate the integrity of a spinal fusion. Also used for early scoliosis to determine presence of structural change when bending to right and left. May be used to localize a herniated disk as shown by limitation of motion at the site of the lesion.

when are AP right & left bending (spinal fusions) performed after fusion procedure?

6 months

Special Views: Lumbar Spine: LATERAL FLEXION & EXTENSION (spinal fusion) purpose

Used to determine whether motion is present in the area of a spinal fusion, indicating nonunion, or to localize a herniated disk as shown by limitation of motion at the site of the lesion.

what special view of the L-spine is this?

Anterior obliques (RAO/LAO)

what special view of the L-spine is this?

L5/S1 AP axial (ferguson)

what special view of the L-spine is this?

AP right & left bending (spinal fusion)