TRAIN CERTIFY MAINTAIN

Acute Care Musculoskeletal (AC MSK)

CURRICULUM

Advanced skills for certification

a. Probe

Linear probe.

b. Knobology

i. Preset. MSK or small parts.

ii. Depth. Start at depth of 5 cm. Adjust as needed

iii. Gain. Default. Adjust as needed.

c. Patient positioning.

Lying supine with sternum fully exposed.

d. Probe orientation

Sagittal (LAX) with probe indicator towards patient’s head and transverse (SAX) with probe indicator towards patient’s right.

e. Probe grip

Pencil grip.

a. External landmark

Sternal body.

b. Internal landmark

Cortex of sternum.

c. Relevant anatomy

Suprasternal (jugular) notch, manubrium, sternal angle (junction of sternum with 2nd rib cartilage), sternal body, xiphisternum, xiphoid process, ridge (junction of sternum with 3rd, 4th, 5th rib cartilage), sternocostal joint, sternoclavicular joint.

d. Area of interest

Anterior bony cortex of sternum.

e. Adequate view

Well-defined (thin, bright white, centred) bony cortex of sternum.

a. Image generation

i. Landmark.

  1. Start the scan at the suprasternal (jugular) notch.
  2. Finish the scan at the xiphoid process.

ii. Optimize image

  1. Decrease depth once you have identified sternal cortex.
  2. Increase probe frequency to increase image resolution.

iii. Technique

  1. Start scan on the external landmark in the midline in LAX.
  2. Slide probe side to side to centre sternum cortex on screen.
  3. Sweep and rock probe to image a well-defined sternal cortex.
  4. Slide caudally keeping cortex well-defined and centred.
  5. End scan when xiphoid process reached.
  6. Rotate probe 90 degrees in SAX and repeat scan.

iv. Interrogate AOI

  1. The AOI is the cortical line of the sternum.
  2. Scan in LAX:
    • Look for a discontinuity/step off of the cortex line.
    • Look for hematoma above fracture site.
  3. Scan in SAX:
    • Look for cortex line to jump to near field (anterior) or far field (posterior) indicating a discontinuity of the bone (aka a fracture!) where the jump occurs.

b. Image interpretation

The following areas should be evaluated and a binary yes/no conclusion made:

i. Sternal fracture? (YES/NO).

a. Rotate probe in short axis to confirm centre of sternum under probe.

a. Technique

i. POCUS only gives information about the interrogated bone surfaces. If the anterior bone surface is evaluated only antero-posterior abnormalities (step off, angulation, displacement) can be appreciated.

ii. It is easier than we think to stray away from sternum midline. Steady your hand and take care to keep your AOI centred at all times.

b. Image interpretation

i. False positives (mistaking these normal findings for fracture sites):

  1. Sternal angle (manubriosternal angle).
  2. Xiphisternum (junction of sternal body with xiphoid process).
  3. Incomplete fusion and growth plates (children).
  4. Failure of midline fusion.
  5. Sternoclavicular or sternocostal joint spaces.

ii. Remember that normal growth plates have:

  1. A well-defined cortex line compared to jagged edges of fracture sites.
  2. No hematoma above them.

iii. Remember that joint spaces will have:

  1. A classic U or V-shape appearance (sharp ‘drop’ of cortical ends on both sides of space).
  2. Non-displaced smooth cortical edges.
  3. When in doubt, compare to unaffected side (for sternoclavicular joints and sternocostal joints).

iv. Sternal angle and xiphisternum are flat bone junctions that will have smooth contours and will not be displaced.

v.  Ridge and incomplete fusion are at the junction of the sternum with the costal cartilage.

 

c. Clinical integration

i. High grade fracture is present when both sides of the fracture fragments are moving independently.

ii. Highly displaced fractures may warrant further investigation of underlying structures. Further imaging and assessment are needed.

iii. If clinical suspicion remains high and POCUS exam is negative, further imaging studies are recommended.

a. Fractures are usually found at the site of maximal tenderness-ask the collaborating patient to point you in the right direction.

b. No need to put pressure on the probe-add lots of gel and ‘float the probe’ to avoid causing added pain to your patient.

a. For a negative scan:

i. Must image a well-defined centred sternal cortex from the jugular notch to the xiphoid process in 2 planes.

ii. No fracture is identified.

b. For a positive scan:

i. Must image a well-defined centred sternal cortex from the jugular notch to the xiphoid process in 2 planes.

ii. A fracture is identified.

Document as per CPoCUS guidelines for positives and negatives according to clinical indications:

a. Sternal fracture      + or –

b. Indeterminate

Prerequisites

Appropriate didactic and practical introduction to technique that must include written materials covering all relevant ultrasound physics, anatomy and theory, a minimum of 30 minutes of live or on-line lectures, and at least 5 introductory proctored sternum scans.

The introductory scans do not count towards certification and do not need to be determinate.

Logged scan requirements

  • 4 sternum determinate scans supervised directly by a CPoCUS MSK Track Instructor for the entirety of the scan.
  • Determinate scans are defined in ‘Determinate scan requirements’.
  • A minimum of 1 scan must be done ‘unassisted’.
  • An unassisted scan is one in which the learner generates a determinate image and uses appropriate troubleshooting maneuvers without any assistance (verbal or physical) from the instructor.
  • There is no requirement for a minimum number of positive scans.
  • All scans must be recorded in a CPoCUS logbook.

Examinations

Pass mark on CPoCUS AC MSK sternum written, practical, and visual examinations PLUS appropriate prerequisites AND logged scans as above.

Note: Prerequisites and/or logged scan requirements may be waived if a candidate is awarded a CPoCUS Exception to Certification (see website for application details).

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