7'7 Posterior Oblique Lumbar Spine

1
7.7 Posterior Oblique Lumbar Spine

• Measure A-P at umbilicus
• Protection Lateral gonad shield
• SID 40 Bucky
• No tube angle
• Film 10 x 12 regular I.D. down

2
Posterior Oblique Lumbar Spine

• Patient stands facing tube. The entire body is
  turned 40 to 45 degrees from A-P. Make sure that
  the shoulders, pelvis and feet are in the same
  plane.
• The side closest to the film will be marked. This
  illustration is an LPO or Left Posterior Oblique

3
Posterior Oblique Lumbar Spine

• The patient left arm is raised away from the
  body. It may be used to hold onto the Bucky.
• The right arm placed at shoulder level.
• Locate the iliac crest closest to the tube.
• Horizontal CR 1 above the iliac crest

4
Posterior Oblique Lumbar Spine

• Center film to horizontal CR.
• Locate the ASIS closest to the tube
• Vertical CR 2 medial to the ASIS closest to the
  tube.
• Collimation top to bottom slightly less than
  film size or from L-1 to S-1

5
Posterior Oblique Lumbar Spine

• Collimation side to side slightly less than film
  size or about 8 inches.
• Install gonad shield with curve following the
  curve of the sacrum.
• Breathing instructions full expiration
• Make exposure and continue with other oblique

6
Posterior Oblique Lumbar Films

• Should see from T-12 to S-1
• Right S I joint should be open
• If there is no rotation, all pars will be seen.
• Always done in pairs

7
Pair of Recumbent Films
8
7.8 Anterior Oblique Lumbar Spine

• Measure A-P at umbilicus
• Protection lateral gonad shield
• SID 40 Bucky
• No tube angle
• Film 10 x 12 regular I.D. down

9
Anterior Oblique Lumbar Spine

• Marker RAO or LAO or R or L
  pronated indicating the side closest to the
  Bucky.
• Patient stands facing Bucky. Entire body turned
  40 to 45 degrees from P-A.

10
Anterior Oblique Lumbar Spine

• Arm closest to Bucky placed behind patient.
• Arm away from Bucky raised and hold onto Bucky.
• Locate the iliac crest
• Horizontal CR 1 inch above the iliac crest.
• Center film to horizontal CR.

11
Anterior Oblique Lumbar Spine

• Palpate the spinous processes.
• Vertical CR 1 to 1 1/2 lateral to the spinous
  processes (toward the tube)
• Install lateral gonad shield into filter holder
  with curve following the sacral curve.

12
Anterior Oblique Lumbar Spine

• Collimation Top to Bottom slightly less than
  film size or from T-12 to S-1
• Collimation side to side slightly less than film
  size or about 8 inches.
• Make sure the lateral gonad shield is not above
  the ASIS.

13
Anterior Oblique Lumbar Spine

• Breathing Instructions Full expiration.
• Make exposure and let patient relax.
• Continue with the other oblique view.

14
Anterior Oblique Lumbar Film

• If patient is not too large, this oblique will
  open disc spaces better than the posterior
  oblique taken erect.
• There will be magnification due to distance of
  spine from film.

15
Anterior Oblique Lumbar Film

• If patient has a significant lordotic curve take
  posterior obliques recumbent.
• Because you can locate the spinous processes,
  anterior obliques are easier to position
  accurately.

16
Lumbar Spine Review

• A-P or P-A and Lateral Lumbopelvic are taken on
  14 x 17 films with the I.D. up.
• The horizontal central ray should not be below
  the ASIS on the A-P Lumbopelvic.
• The oblique views and lateral lumbar view has the
  same horizontal central ray placement. One inch
  above the iliac crest.

17
Lumbar Spine Review

• The accurate location of the iliac crest is key
  to lumbar region positioning. One large and
  muscular patients this may be difficult.
• Feel down the mid coronal plane from the lower
  ribs to the crest. Failure to start at the ribs
  can result in location of the ASIS in error.

18
Lumbar Spine Review

• Recent research has noted that the ASIS is about
  three inches below the iliac crest.
• The symphysis pubis is about three inches below
  the ASIS. Since locating the ASIS is less
  sensitive than locating the pubis, this distance
  can make placement of the gonad shield easier on
  both the doctor and patient.

19
Sacral Base and Spot of L5 S1

• First area where measurements are taken at the
  trochanters.
• Often spot lateral views can be avoided by taking
  a good quality lateral. Avoid any rotation.
• If the patient has a scoliosis with the curve
  convexity to the right, take a right lateral
  lumbar view.

20
Sacral Base View

• A-P view taken on male patients and large female
  patients.
• Every effort to make sure the female patient is
  not pregnant is very important. The primary beam
  is directed through the ovaries.
• If the female patient is past childbearing age,
  A-P views are taken.

21
Sacral Base View

• The A-P or P-A sacral base will use the greatest
  tube angle of all routine spinal views.
• The SID must be adjusted to achieve proper
  collimation.
• These are spot views so borders of collimation
  should be seen

22
Sacral Base View

• Unless the view is taken to evaluate the
  Sacroiliac Joints, collimation should be 5
  square for A-P views.
• Four borders should be seen on any sacral base
  view. Proper collimation will reduce scatter
  radiation and improve detail.

23
Sacral Base View

• The P-A view is collimated to slightly less than
  film size because the increased object to film
  distance will result in magnification.
• These views will require longer exposure times
  compared to the A-P lumbopelvic so breathing
  instructions and the patient remaining still are
  very important.

24
Spot Lateral L5/S1 View

• The most common spot view of the lumbar spine is
  the L5 S1 spot film. Recumbent radiography
  requires angulation or sponges to account for
  differences in waist and pelvic diameter.
• Because of erect radiography, we rarely need to
  take the view.

25
Spot Lateral L5/S1 View

• It can be very helpful to look at the lateral
  lumbar view to pin point the location of L5 S1
  compared to the iliac crest and mid coronal
  plane.
• Spot lateral views can be taken of any vertebra
  to improve detail.

26
7.10 A-P Sacral Base

• Measure A-P at trochanters
• Protection Bell for males none for female
  females usually taken P-A
• SID 40 Bucky
• Tube angle 30 degrees cephalad
• Film 8 x 10 I.D. up

27
A-P Sacral Base

• Patient stands facing tube with feet shoulders
  width apart.
• SID adjusted for tube angle.
• Locate ASIS
• Horizontal CR centered to the ASIS.
• Film centered to Horizontal CR.

28
A-P Sacral Base

• Vertical CR mid-sagittal plane
• Collimation 5 x 5 unless SI Joints are of
  primary interest. For SI Joints, collimate
  slightly less than film size.
• Breathing Instructions Full expiration
• Make exposure and let patient relax.

29
A-P Sacral Base Film

• There should be no rotation.
• L5/S1 disc space should be open.
• Sacroiliac Joints should be open.
• Useful in detection of sacralization.

30
7.11 P-A Sacral Base

• Measure A-P at trochanters
• Protection Males do AP Females none
• SID 40 Bucky
• Tube angle 30 degrees caudal
• Film 8 x 10 I.D. up

31
A-P Sacral Base

• Patient stands facing Bucky with feet shoulders
  width apart.
• SID adjusted for tube angle.
• Locate PSIS
• Horizontal CR centered to the PSIS or L5/S1.
• Film centered to Horizontal CR.

32
P-A Sacral Base

• Vertical CR mid-sagittal plane
• Collimation slightly less than film size.
• Breathing Instructions Full expiration
• Make exposure and let patient relax.

33
P-A Sacral Base Film

• There should be no rotation.
• The object to film distance will cause
  magnification.
• L5/S1 disc space should be open.
• Sacroiliac Joints should be open.
• Useful in detection of sacralization.

34
7.12 Lateral Spot L5/S1

• Measure Lateral at the trochanters
• Protection Lateral gonad shield
• SID 40 Bucky
• No tube angle when taken erect
• Film 8 x 10 I.D. up

35
Lateral Spot L5/S1

• Patient stands in lateral position. Arms should
  be across chest.
• Get patient as close to the Bucky as possible.
• Make sure there is no rotation.
• Locate the iliac crest

36
Lateral Spot L5/S1

• Horizontal CR Two inches below iliac crest.
• Vertical CR Mid- coronal to 1 inch posterior to
  mid-coronal plane.
• Hint look at lateral lumbar film to determine
  where to center.

37
Lateral Spot L5/S1

• Center film to Horizontal CR.
• Collimation 5 x 5
• Breathing Instructions Full Expiration
• Make exposure and let patient relax.

38
Lateral Spot L5/S1 Film

• Note error in I.D. location.
• No rotation
• Should see all of L5 and S1 on film.
• Disc space should be open.
• If patient has a leg length problem or scoliosis
  adjust laterality.

39
Sacroiliac Joints

• The A-P or P-A Sacral Base will generally provide
  a good view of the sacroiliac joints.
• When another view is needed or the sacral base
  view does not demonstrate the joints adequately,
  oblique views are taken.
• To open the S.I. Joints, a shallow oblique of 25
  to 30 degrees is taken.

40
Sacroiliac Joints

• When Posterior Oblique Views are taken, the S.I.
  Joint away from the film will open.
• Since the Lateral Gonad Shield is used on the
  Posterior Oblique Views are routine.

41
Sacroiliac Joints

• There are two ways to properly mark S.I. Joint
  Posterior Oblique Views
• RPO or LPO markers may be used to document
  the side closest to the film.
• R or L can be used lateral to side being
  taken since only that S.I. Joint that is viewed.
  Since this is a unilateral view, this way is
  preferred.

42
7.13 Posterior Oblique S.I. Joints

• Measure A-P at trochanters
• Protection Lateral Gonad Shield
• SID 40 Bucky
• No tube angle
• Film 8 x 10 I.D. down

43
Posterior Oblique S.I. Joints

• Patient stands facing the tube. Rotate the
  affected side 25 to 30 degrees away from the
  film.
• Make sure that the unaffected side is as close to
  the film as possible.
• Locate the ASIS away from the Bucky.

44
Posterior Oblique S.I. Joints

• Horizontal CR 1 inch below the ASIS away from
  the Bucky.
• Vertical CR 1 inch medial to the ASIS away from
  the Bucky.
• Center film to horizontal central ray.

45
Posterior Oblique S.I. Joints

• Collimation top to bottom slightly less than
  film size
• Collimation side to side slightly less than film
  size
• Place lateral gonad shield at level of ASIS with
  curve following the curve of the sacrum.

46
Posterior Oblique S.I. Joints

• Breathing Instructions Full expiration
• Make exposure and let patient relax.
• Proceed with the other side. Oblique S.I. Joints
  are taken in pairs.

47
Oblique S.I. Joint Film

• The same degree of rotation is key to comparison
  both joints.
• If rotation is too much, the joint will close.
• Large or Obese patients may require the use of
  the 10 x 12 film size.
• Either marking conviction can be used.

48
End of Lecture

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