N/A
N=144
Cryoanalgesia to Treat Post-Amputation Phantom Limb Pain: A Department of Defense Funded Multicenter Study
Post-Amputation Phantom Limb Pain
Bottom Line
View on ClinicalTrials.gov: NCT03449667 ↗Enrolled (actual)
144
Serious AEs
0.9%
Results posted
Feb 2023
Primary outcome: Primary: Change From Baseline in Average Daily Phantom Pain Intensity — 0.5; 0 score on a scale
Study Design & Population
- Study type
- Interventional
- Phase
- N/A
- Interventions
- Cryoneurolysis (Device); Sham Comparator (Device)
- Age
- Adult, Older Adult · 18+ yrs
- Sex
- All
- Sponsor
- University of California, San Diego
- Primary completion
- Aug 2021
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Change From Baseline in Average Daily Phantom Pain Intensity |
0.5; 0 | — |
| SECONDARY Average Daily Phantom Pain Intensity |
5; 5; 0; 1; 3; 3.5 | — |
| SECONDARY Worst Daily Phantom Pain Intensity |
8; 8; 2.5; 3; 6; 6 | — |
| SECONDARY Residual Limb Pain, Average |
3; 3; 0; 0; 0; 0 | — |
| SECONDARY Residual Limb Pain, Worst |
6; 5; 0; 0; 0; 0 | — |
| SECONDARY Patient Global Impression of Change |
7; 6; 5; 4; 4; 4 | — |
| SECONDARY Brief Pain Inventory Interference Subscale |
36; 34; 0; 0; 7; 19 | — |
| SECONDARY Beck Depression Inventory |
10; 9; 4; 2; 0; 0 | — |
| SECONDARY Phantom Limb Pain Frequency |
24; 24; 1; 2; 9; 24 | — |
| SECONDARY Phantom Limb Pain Duration |
24; 24; 0; 0; 0; 3 | — |
| SECONDARY Non-painful Phantom Sensations Frequency |
24; 24; 0; 1; 9; 24 | — |
| SECONDARY Non-painful Phantom Sensations Duration |
24; 24; 0; 0; 1; 24 | — |
| SECONDARY Residual Limb Pain Frequency |
5; 12; 0; 0; 0; 0 | — |
| SECONDARY Residual Limb Pain Duration |
24; 24; 1; 15; 1; 15 | — |
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 research study will include subjects with an existing lower extremity 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 target nerve(s) involved with the phantom pain. Although not required, each subject may return four 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.
Eligibility Criteria
Inclusion Criteria
- Adult patients of at least 18 years of age
- with a lower limb traumatic or surgical amputation at least 12 weeks prior to enrollment distal to the hip (femoral head remaining)
- who experience at least moderate phantom limb pain-defined as a 3 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.
- accepting of a cryoneurolysis procedure
- 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.
Exclusion Criteria
- 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.
Data sourced from ClinicalTrials.gov (NCT03449667). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.