without getting injected or entering the patient's tissue, but the ulti-
mate effect is quite drastic. The tip of the probe freezes, creating an
ice ball that encompasses the target nerve and subsequently
freezes. Result: The nerve stops working and the patient gets pain
relief ranging from 4 to 8 weeks, says Dr. Ilfeld.
For outpatient orthopedic procedures, the potential benefits of
cryoanalgesia are significant, says Dr. Ilfeld, adding that it's a safe
and familiar procedure because it's essentially the same as a periph-
eral nerve block. "Anesthesiologists who know how to do peripheral
nerve blocks with ultrasound guidance already know how to do
cryo," says Dr. Ilfeld.
Another benefit of cryoanalgesia is the cost. After the initial pur-
chase of the device, facilities will only need to pay for nitrous oxide
and to resterilize reusable probes (although disposable probes are
available).
What's needed is more research into how cryo will be applied to
common orthopedic procedures. "With procedures like shoulder
arthroplasty and rotator cuff repair, we'd never do cryo on the entire
brachial plexus, but we'd possibly treat the suprascapular nerve that
innervates about two-thirds of the joint capsule," says Dr. Ilfeld. "But
these assumptions are all theoretical until we have quality randomized
trials to draw from."
5. Peripheral nerve stimulation
The FDA cleared peripheral nerve stimulation decades ago for chronic
pain, but it could prove useful in managing acute pain. You insert the
lead of the nerve stimulator in a similar manner as a perinatal catheter
using ultrasound guidance, but it delivers a small electric current to the
nerve instead of a local anesthetic. Physicians only have to get the lead
within 1 cm to 2 cm of the nerve, and it can remain in place for up to 60
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