Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT04538417 |
Other study ID # |
IRB 106250 |
Secondary ID |
|
Status |
Completed |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
October 27, 2019 |
Est. completion date |
August 30, 2023 |
Study information
Verified date |
March 2024 |
Source |
University of Utah |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
To assess changes in pain, physical function, and health-related quality of life in patients
with post-amputation neuroma-associated residual limb pain after cooled radiofrequency
ablation.
Description:
Residual limb (RLP) and phantom limb pain (PLP) affects most amputees at some point in their
life1. The incidence of PLP has been estimated to range between 50 - 80%. RLP prevalence has
been estimated to be 43%. The peak of onset is bimodal and often appears within the first
month and second year after amputation. RLP is more common in the first year after
amputation, with PLP becoming the predominate amputee pain complaint after one-year
post-amputation.
Both RLP and PLP fall under the umbrella term "post-amputation pain." While these conditions
are frequently found in combination, their clinical features and underlying causes are
distinct. PLP is a painful sensation in the distribution of the missing limb. Following
amputation, abnormalities at multiple levels of the neural axis have been implicated in the
development of PLP; changes include cortical reorganization, reduced inhibitory processes at
the spinal cord, synaptic response changes and hyperexcitability at the dorsal root ganglion,
and retrograde peripheral nerves shrinkage.
Residual limb pain has been called "neuroma pain" and is mechanistically distinct from PLP11.
Neuromas may form as early 6-10 weeks after nerve transection, and are thought the produce
ectopic neural discharges resulting in severe pain. Evidence suggests RLP and PLP commonly
co-occur and patients may struggle to differentiate between these pain types. Risk factors
include female sex, upper extremity amputation, pre-amputation pain, residual pain in
contralateral limb, and time since amputation.
Depression, anxiety, and stress are known to exacerbate PLP / RLP. Patients experiencing PLP
and RLP also experience a higher incidence of indecisiveness, suicidal ideation, and thoughts
of self-harm8. Current guidelines for treatment of PLP and RLP are not standardized.
Treatments includes pre-operative analgesia, neuromodulation mirror therapy, imagery,
acupuncture, transcranial stimulation, deep brain stimulation, and medications (including,
but not limited to: TCAs, SSRIs, gabapentinoids, sodium channel blockers, ketamine, opioids,
and NSAIDs). Many agents have been injected in neuromas. These include local anesthetic,
phenol, alcohol, and botulinum toxin. These oral, intravenous, and nonpharmacological
modalities have demonstrated limited success in the treatment of PLP / RLP. Neuroma
cryoablation has been used, but this method of neural destruction poses technical challenges
related to cumbersome needle placement and the requirement for time-intensive freeze-thaw
cycles.
Conventional RFA has been studied on RLP. Zhang et. al treated 13 patients with painful stump
neuromas. The study started with alcohol neurolysis before using ultrasound-guided RFA for
refractory cases. The frequency of sharp pain was reduced in all RFA-treated patients. Kim
et. al described a case in which ultrasound-guided RFA was successfully used to treat a
sciatic neuroma of an above-knee amputee.
No outcome literature on the effectiveness of C-RFA technology has been published. C-RFA is
similar in mechanism to conventional RFA: a thermal lesion is created by applying
radiofrequency energy through an electrode placed at a target structure. In C-RFA, a constant
flow of ambient water is circulated through the electrode via a peristaltic pump, maintaining
a lowered tissue temperature by creating a heat sink. By removing heat from tissues
immediately adjacent to the electrode tip, a lower lesioning temperature is maintained,
resulting in less tissue charring adjacent to the electrode, less tissue impedance and more
efficient heating of target tissue. The volume of tissue heated, and the resultant thermal
lesion size is substantially larger with C-RFA, conferring an advantage over conventional
RFA. Further, given the spherical geometry and forward projection the C-RFA lesions beyond
the distal end of the electrode, the RFA probe can be positioned at a range of possible
angles and still capture the target neural structure, whereas more fastidious, parallel
positioning is required with conventional RFA. These technical advantages increase the
probability of successful denervation of neural pain generators that have variability in
anatomic location. Additionally, a longer lesion of the RLP-generating nerve may be more
reliably achieved with C-RFA compared to conventional RFA.
As such, the present study aims to define the attributable effect of cooled RFA on pain,
physical function, and health-related quality of life in patients with post-amputation
neuroma-associated residual limb pain. This prospective single-arm pilot study is intended to
inform a future properly powered randomized controlled trial.