RAPTIR Block for Elbow Dislocation

While the appearance of the dislocated elbow on x-ray is fairly obvious, take a look at how it appears on ultrasound. The linear transducer was placed on the dorsal aspect of the distal upper arm and oriented in the long axis. In the pre-reduction ultrasound, appreciate the proximity of the olecranon to the near-field and notice the change in its distance to the humerus in the post-reduction imaging.

With proper training, reduction under regional anesthesia is a great alternative to procedural sedation. While the infraclavicular brachial plexus block could provide proper anesthesia to the elbow, the steep angle required in this approach to access the axillary sheath below the axillary artery adds a layer of technical difficulty. In the RAPTIR (Retrograde Approach to the Infraclavicular Region) block, the transducer is held infraclavicular while the needle approach is supraclavicular, and the needle is carefully advanced past a “blind spot” from clavicular shadowing until it is visualized on the ultrasound screen.

ONSD and Idiopathic Intracranial Hypertension

27F no PMH presenting with a nontraumatic headache and with normal vitals

1. What are the normal values for the ONSD?

Measured from the inner-edge to inner-edge, 3 mm posterior to the retina, for the upper limit of normal of the ONSD is:
– up to 4 mm in infants
– up to 4.5 mm in children
– up to 5 mm in adults
Measurements above 5 mm (bilaterally) classically correspond with elevations in intracranial pressure above 20 mmHg

ONSD

2. What is visualized in picture B?

Crescent Sign – The separation of the optic nerve sheath from the nerve due to increased subarachnoid fluid
Nipple Sign – Protrusion of the ONSD into the vitreous chamber, >0.6 mm correlates with papilledema
Differentiation between acute and chronic elevations in ICP may be aided by the crescent sign, the sonographic correlate of papilledema

Correlation signs of papilledema

3. What is the significance of the ONSD:ETD Ratio?

While taking multiple measurements and averaging them is useful for accuracy, studies have shown upper limit ONSD ranges from 4.8 to 6.2mm.
There has been increasing evidence that the ONSD:ETD Ratio is more accurate.
One study in patients with TBI was able to predict intracranial hypertension with a threshold ratio value of 0.25 with a sensitivity of 90% and a specificity of 82.3%.

ONSD:ETD Ratio

In our patient’s case, the ONSD:ETD Ratio is 0.318. Confirmatory LP was performed and found to be elevated confirming her diagnosis of Idiopathic Intracranial Hypertension.

2/14/22

We are bringing back Image of the Week! However we renamed it the Sono of the Century. We hope you enjoy!

38 y/o F p/w sublingual pain and swelling
The sublingual space was evaluated with the endocavitary transducer

Purulence was expressed

Q) What is the treatment for acute suppurative sialadenitis?
A) Antibiotics (e.g. clindamycin, amoxicillin/clavulanic acid), salivary massage, hydration, sialogogues (e.g. lemon drops, sour lozenges).

IOTW 5/03/21

27 y/o F p/w right flank pain

  1. What is the finding labeled “A”?
    • These adjacent hyperechoic structures with shadowing are representative of intrarenal calculi. CT demonstrated that this was actually a partial staghorn calculus.
  2. How would you describe the structure labeled “B” in sonographic terms? What do you think this is?
    • This is a hypoechoic complex round mass with posterior acoustic enhancement containing internal debris consistent with perinephric abscess.
  3. How would you grade the hydronephrosis on image “C”?
    • Notice that the dilated calyces are beginning to form the “bear paw” sign. This suggests that this is at least high-grade mild hydronephrosis.