transmission as a means of controlling pain. The therapy is performed through the
use of cryoprobes which are usually 16 or 14 gauge probes inserted through the
skin onto the target nerve. The cold temperature is created by passing a gas at
relatively high pressure through a small central channel in the probe. Once the
gas reaches the tip of the probe, it enters an expansion chamber which is at much
lower pressure. The high pressure gas entering the chamber rapidly expands
causing cooling of the gas and of the tip of the cryoprobe. Generally the tips of
these probes may be cooled to as low as -70 degrees C. This extreme cold then
causes the tissues nearby to form an iceball at the tip of the probe. The iceball,
when close enough to a nerve, causes entrapment of the nerve in the iceball and
therefore freezes the nerve and interrupts pain
transmission for up to 3-6 months.
Nerves often targeted with this technique include the intercostal nerves of the
ribs for post thoracic surgery pain, peripheral nerves which are entrapped such as
ilioinguinal (to the groin), neuromas (such as in the foot), the medial branches to
the facet joints, etc.
During the procedure, the patient may be intermittently sedated if no nerve
stimulation is required to accurately localize the intended nerve target. Since the
closer to the nerve, the more effective is the technique, it would follow that in
cases where there is not an easy way to find the nerve, awake electrical
stimulation of the nerve may be useful prior to cryoneurolysis. Generally, this
procedure is performed as an outpatient with mild or no sedation. Small incisions
will be made to allow entry of the cryoprobe. Each nerve is frozen for 3 minutes x
2-3 repetitions. The patient receives small bandages over the incisions and goes
home. Usually pain relief occurs within the first 3 days.
Complications potentially include bleeding, infection, nerve injury, or penetration
of the surrounding structures with associated complications. Side effects include
muscle pain, increased soreness (transient), and pain from lying in the position
necessary for the procedure.
Recovery time is almost zero since no nerves are burned.
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