Ultrasound of the Month Case 38

Clinical History •

35-year-old male with a history of severe motor vehicle related trauma resulting in amputation with left hip disarticulation 3 years earlier

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The patient’s clinical course was complicated by recurrent regional wound infections requiring multiple plastic surgery revisions and closures

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The patient now reports left lower extremity discomfort with pain and tingling with a sensation of “phantom limb pain”

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An MRI examination was performed for further evaluation of the amputation site and the sciatic nerve

Ultrasound of the Month – Case 38

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Ultrasound of the Month – Case 38

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Clinical History

• Following review of the MRI and evaluation by the patient’s pain management physician, cryoablation of the sciatic nerve stump neuroma was suggested • Ultrasound guidance during the procedure was requested and provided to insure accurate localization of the stump neuroma

Ultrasound of the Month – Case 38

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Cryoablation of nerves

• Cryoablation involves the controlled freezing and resultant damage of nerve tissue

• The cryoablation probe utilizes pressurized nitrous oxide to achieve a probe tip temperature of -70 degrees Celsius, forming an intra-neural “ice ball” • The resulting damage to the nerve may provide symptom relief for up to and occasionally exceeding one year

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Cryoablation of stump neuromas

• Real-time sonographic imaging is utilized to first anesthetize the stump neuroma • The cryoablation probe is then advanced into the neuroma • Depending on the size of the abnormal nerve, multiple probe positions and areas of freezing may be necessary for full ablation

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Patient outcome

• Within 1 week of the cryoablation procedure, the patient noted significant improvement in his presenting symptoms and a greatly diminished sensation of his prior “phantom limb”.

• If symptoms recur, the cryoablation may be repeated or, as indicated, definitive surgery can be performed

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