Cryoanalgesia to Treat Phantom Limb Pain Following Above-Knee Amputation
Completed · Not applicable · Has a placebo group
Conditions studied: Amputation, Surgical, Amputation, Traumatic, Phantom Limb Pain, Phantom Pain Following Amputation of Lower Limb
In brief
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.
Key facts
- Study ID
- NCT06071715
- Run by
- University of California, San Diego
- People needed
- 12
- Starts
- 2024-02-12
- Expected to finish
- 2025-10-09
- Last updated by the study team
- 2026-04-08
Who can join
Age: 18 and older. Sex: any. Healthy volunteers: not accepted.
You may qualify if…
- Adult patients of at least 18 years of age
- Trans-femoral traumatic or surgical amputation at least 12 weeks prior to enrollment distal to the hip (femoral head remaining)
- Experiencing at least moderate phantom limb pain-defined as a 4 or higher on the Numeric Rating Scale (NRS; 0-10, 0= no pain; 10=worst imaginable pain)-at least daily for the previous 2 months
- willing to avoid both changes to their analgesic regimen as well as elective surgical procedures from 1 month prior to and at least 4 months following the initial cryoneurolysis procedure.
You may not qualify if…
- allergy to amide local anesthetics
- pregnancy
- incarceration
- inability to communicate with the investigators
- morbid obesity (body mass index > 40 kg/m2)
- possessing any contraindication specific to cryoneurolysis such as a localized infection at the treatment site, cryoglobulinemia, cold urticaria and Reynaud's Syndrome
Where it is running
- University of California San Diego — La Jolla, California, United States
Full record on ClinicalTrials.gov
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