Lumbar Spine, Sacrum, Coccyx, SI joints

What is Aurora’s L-spine routine?

AP, lateral, spot

Explain patient prep for AP L-spine

• empty bladder (ideally)

• empty bowels (ideally)

• remove clothing

Explain patient and IR position for AP L-spine

• 14 × 17 LW

• AP or PA

• recumbent or erect

• arms out of the way

• flex hips and knees

Why do you flex knees for AP L-spine images?

• reduces lordotic curve

• opens intervertebral disc spaces

• places vertebrae parallel to IR

• less OID

What are some pros and cons for doing an AP L-spine PA?

Pros: more comfortable, intervertebral disc spaces are more parallel, less gonadal dose

Cons: more OID

What is SID for L-spine images?

40”

What is breathing for L-spine?

expiration

Explain the CR for AP L-spine

1. lumbosacral spine

   1. center at top of crest and MSP

2. lumbar spine

   1. center 1.5” above crest and MSP

What is demonstrated on an AP L-spine image (film eval)?

• lumbar bodies, open disc spaces, transverse processes

• SI joints must be on image

• collimated side to side

• marker R or L up or down (doesn’t matter)

• if upright, annotate

• sent as if person is standing in front of you

Explain patient and IR position for lateral L-spine

• 14 × 17 LW

• left lateral preferred

• recumbent or erect

• flex knees and hips

• arms bent in front of patient

Explain the CR for lateral L-spine

1. lumbosacral

   1. center at crest and MCP

2. lumbar

   1. center 1.5” above crest and MCP

3. if spine is not parallel to IR:

   1. 5^o(men)-8^o(women) caudal angle

   2. place a sponge under

Why do you place a lead strip next to the patient for a lateral L-spine?

cleans up scatter

What is demonstrated on a lateral L-spine image (film eval)?

• lateral view of vertebral bodies, disc spaces, spinous processes, lumbosacral junction, intervertebral foramina

• collimate side to side

• mark down

• sent as a right lateral

Explain the trauma/myelogram lateral L-spine

• dorsal(trauma) or ventral(myelogram) decubitus

• horizontal beam with IR on patient’s side

• grid

• 40”

• CR at crest and MCP

Explain patient and IR position for the L-spine spot image

• recumbent or erect

• true lateral

  • left preferred

  • place spine parallel to table

• flex knees and hips

• check interiliac line

Explain the CR for a L-spine spot image

• if L5-S1 space is closed on lateral image, shoot perpendicular(or same angle as used for lateral)

• if L5-S1 space is open on lateral image, shoot with 5-8^o caudal angle

• CR must be parallel to interiliac plane

• centered 2” posterior to ASIS and 1½“ inferior to crest

What is demonstrated on a spot L-spine image (film eval)?

• lateral view of lumbosacral junction

• upper sacrum, open L4-L5, L5-S1 disc spaces

• collimate

• sent as a right lateral

Explain spondylolisthesis

• result of spondylolysis

• forward slipping of 1 vertebra over another

• surgical repair

Explain patient and IR positioning for the oblique lumbar spine

• AP

• supine or erect

• support under shoulder and hip

• average 45^o (more angle for more superior joints)

Explain central ray for oblique lumbar spine

• RPO, LPO or RAO, LAO

• CR perpendicular

• center 1½“ above crest and 2” medial to elevated ASIS

• DON’T USE AEC

What is demonstrated on an oblique L-spine image (film eval)?

• open zygapophyseal joints

• superior and inferior articulating processes in profile

• possible spondylolysis

Explain over and under rotation for oblique L-spines

over rotation: pedicle is too posterior in the vertebral body

under rotation: pedicle is too anterior in the vertebral body

Which side is demonstrated in a lumbar oblique?

AP - Side down (near to IR)

PA - Side up (far from IR)

Explain the patient and CR positioning for the AP axial L5-S1 joint image

• supine

• extend legs with support under knees

• center at ASIS and MSP

• 30^o cephalic for males, 35^o for females

What is demonstrated on the AP axial L5-S1 joint image? (film eval)

• open L5-S1 joint in AP projection

• any pathology of L5-S1 and SI joints

Explain the flexion and extension lumbar spine images

• usually ordered with an L-spine series

• erect or recumbent, true lateral

• hyperflexion - fetal position with legs drawn up

• hyperextension - move torso and legs posteriorly

• center perpendicularly to crest and MCP

What do the flexion and extension L-spine images demonstrate? (film eval)

• post spinal fusion mobility

• range of motion

• can localize a herniated disc due to limited movement at site

• marker down and anterior

• annotate with “flexion” or “extension”

• collimate

What is scoliosis?

lateral curvature of the spine

Explain scoliosis surveys

• AP/PA and lateral

• Digital: 14 × 17 LW

• CR: 14 × 36 LW

• 60-72” SID

• positioning

  • erect

  • arms out of the way

  • remove shoes

  • cervical through lumbar

  • PA to reduce dose

  • shadow shielding

Explain shadow shielding

• lead filters attached to collimator with magnets

• breast and gonadal shielding

Explain right/left bending lumbar spine

• AP or PA, recumbent or erect

• pelvis remains stationary

• 40-60” SID

• 14 × 17 LW for thoracolumbar

• 14 × 36 LW for scoliosis

• bottom of IR 1-2 inches below crest

What do the right/left bending lumbar spine images demonstrate? (film eval)

• evaluates curvature of spine

• includes L-spine and lower T-spine

Explain AP Axial SI joint images

• 10 × 12 CW

• 40” SID

• supine with legs extended

• 30^o cephalic angle for men, 35^o cephalic for women

• center at MSP, 2” inferior to ASIS (or 2” above symphysis)

What is demonstrated on AP Axial SI joint images? (film eval)

• SI joints

• L5-S1 intervertebral joint

• marker placed down on either side

Explain AP oblique SI joint images

• 10 × 12 CW

• 40” SID

• supine with visualized side up 25-30^o

• support from hip to shoulder

• center 1” medial to upside ASIS

What is Aurora’s SI routine?

pelvis, left oblique, right oblique

What is demonstrated on an AP oblique SI joint image?

• profile view of joint farthest from IR

• any pathologies

• RPO - left SI joint

• LPO - right SI joint

• marker placed down on demonstrated side (side up for AP)

Explain PA SI joints (alternate to AP)

• prone

• demonstrates side down

• RAO - right SI joint

• LAO - left SI joint

Explain the AP sacrum image

• 10 × 12 LW

• 40” SI

• supine or prone with legs extended

  • supine: 15^o cephalic

  • prone: 15^o caudal

• centered at MSP and 2” superior to symphysis

What is demonstrated on an AP sacrum image? (film eval)

• frontal view of sacrum without foreshortening or superimposition

• collimated

• marker placed down

Explain the AP coccyx image

• 10 × 12 LW

• 40” SID

• supine with legs extended

• 10^o caudal angle entering at MSP and 2” superior to symphysis

What is demonstrated on an AP coccyx image? (film eval)

• frontal view of coccyx without superimposition

• open segments of coccyx

• collimated

• marker placed down on either side

Explain the lateral sacrum image

• 10 × 12 LW

• 40” SID

• true lateral recumbent (right or left)

• flex hips and knees

• center 3-4” posterior to ASIS

What is demonstrated on a lateral sacrum image? (film eval)

• lateral view of sacrum (look at ilia to determine rotation)

• collimated

• sent as a left lateral

• mark anterior and down

Explain the lateral sacrum image

• 10 × 12 LW

• 40” SID

• true lateral (right or left) with hips and knees flexed

• center 3-4” posterior and 2” distal to ASIS

Explain the lateral sacrum/coccyx combined image

• most places will do this instead of separate laterals

• center at ASIS or 1” below and 3-4” posterior to ASIS

What techniques are used for L-spine images? (AP, obliques, lateral, spot)

AP: 80 kVp @ 20-25 mAs

Obliques: 80 kVp @ 25-32 mAs

Lateral: 85 kVp @ 40-50 mAs

Spot: 90 kVp @ 63-80 mAs

What techniques are used for sacrum and coccyx images? (AP, lateral)

AP: 80 kVp @ 12-16 mAs

Lateral: 85 kVp @ 32-40 mAs

What techniques are used for SI joint obliques?

80 kVp @ 12-16 mAs

What S# should L-spine, sacrum/coccyx, and SI joints be?

L-spine: 100-500

sacrum, coccyx, SI: 200-700