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Cryoanalgesia to Treat Phantom Limb Pain Following Above-Knee Amputation
Sponsor: University of California, San Diego
Summary
When a limb is severed, pain perceived in the part of the body that no longer exists often develops and is called "phantom limb" pain. Unfortunately, phantom pain goes away in only 16% of afflicted individuals, and there is currently no reliable definitive treatment. The exact reason that phantom limb pain occurs is unclear, but when a nerve is cut-as happens with an amputation-changes occur in the brain and spinal cord that actually increase with worsening phantom pain. These abnormal changes may often be corrected by putting local anesthetic-called a "nerve block"-on the injured nerve, effectively keeping any "bad signals" from reaching the brain with a simultaneous resolution of the phantom limb pain. However, when the nerve block resolves after a few hours, the phantom pain returns. But, this demonstrates that the brain abnormalities-and phantom pain-that occur with an amputation are not necessarily fixed, and may be dependent upon the "bad" signals being sent from the injured nerve(s), suggesting that a very long peripheral nerve block-lasting many months rather than hours-may permanently reverse the abnormal changes in the brain, and provide definitive relief from phantom pain. A prolonged nerve block lasting a few months may be provided by freezing the nerve using a process called "cryoneurolysis". The ultimate objective of the proposed research study is to determine if cryoanalgesia is an effective treatment for intractable post-amputation phantom limb pain. The proposed pilot study will include subjects with an existing above-knee amputation who experience intractable daily phantom limb pain. A single ultrasound-guided treatment of cryoneurolysis (or sham block-determined randomly like a flip of a coin) will be applied to the major nerves of the thigh. Although not required, each subject may return 4-6 months later for the alternative treatment (if the first treatment is sham, then the second treatment would be cryoneurolysis) so that all participants have the option of receiving the active treatment. Subjects will be followed for a total of 12 months with data collected by telephone.
Official title: Cryoanalgesia to Treat Phantom Limb Pain Following a Trans-Femoral (Above-Knee) Amputation: A Randomized, Sham-Controlled Pilot Study
Key Details
Gender
All
Age Range
18 Years - Any
Study Type
INTERVENTIONAL
Enrollment
12
Start Date
2024-02-12
Completion Date
2025-10-09
Last Updated
2026-04-08
Healthy Volunteers
No
Conditions
Interventions
ACTIVE cryoneurolysis
Cryoneurolysis of the major nerves of the thigh (or their distal counterparts) in the residual limb: The cryoneurolysis device will be triggered using 1 cycle of 5.5-minute argon activation followed by a 30-60 second defrost period with helium Initial treatment: Cryoneurolysis of the major nerves of the thigh (or their distal counterparts) in the residual limb: The cryoneurolysis device will be triggered using 1 cycle of 5.5-minute argon activation followed by a 30-60 second defrost period with helium (Varian) or 2 cycles of 2-minute gas activation with an active probe separated by a 30-60 second defrost (Epimed). For active treatment, the gas will be deployed to the probe tip where a drop in temperature will result in cryoneurolysis.
SHAM cryoneurolysis
SHAM cryoneurolysis of the major nerves of the thigh (or their distal counterparts) in the residual limb: The cryoneurolysis device will be triggered using 1 cycle of 5.5-minute argon activation followed by a 30-60 second defrost period with helium (Varian) or 2 cycles of 2-minute gas activation with a sham probe separated by a 30-60 second defrost (Epimed). However, for sham treatment, the gas is NOT deployed to the probe tip and therefore there is NO drop in temperature with NO resulting cryoneurolysis.
Locations (1)
University of California San Diego
La Jolla, California, United States