Phantom Limb Pain (PLP), Primary/Secondary Scar Hyperalgesia
Conditions
Keywords
lidocaine, phantom limb pain (PLP), Primary/secondary scar hyperalgesia
Brief summary
Phantom limb pain (PLP) and scar hyperalgesia (SH) are frequent problems after amputation; in particular most persons who undergo limb amputation will experience phantom pain. The neuropathic nature of PLP suggests the involvement of both peripheral and central neurological mechanisms, including neuroplastic changes in the central nervous system. PLP as other central nervous system-related pain syndromes remains a challenge for treatment. Scar hyperalgesia involves peripheral mechanisms and results frim the production of substances liberated by damaged skin cells. These inflammatory substances lower the pain threshold by altering the chemical environment of skin nerve endings. Scan hyperalgesia is associated with secondary mechanical hyperalgesia in the skin area around the scar. The lidocaine patch 5% is a topical analgesic acting by blocking sodium channels of peripheral nerve endings and by inhibiting ectopic discharges in sensitized and hyperactive cutaneous nociceptors. The patch is noninvasive, with minimal systemic absorption resulting in a reduced risk of drug-drug interaction. In addition, a central analgesic effect of lidocaine has been suggested. The lidocaine patch 5% is currently licensed for the treatment of symptomatic postherpetic neuralgia. It also has been successfully used in patients with other neuropathic pain states, such as entrapment neuropathies, painful idiopathic distal sensory polyneuropathies and postoperative/post traumatic neuropathic chronic cutaneous pain. The lidocaine patch has not been studied for the management and prevention of phantom limb pain. The aim of the present research is to investigate if a lidocaine patch 5% is effective for reducing PLP and primary/secondary scar hyperalgesia. The hypothesis is that persistent peripheral nociceptive input from the stump after surgery may drive maladaptive cortical reorganization leading to chronic central pain and thus promote chronic phantom limb pain. Treating scar hyperalgesia on the stump with topical lidocaine may reduce the activity of peripheral nociceptive afferents and thus decrease the likelihood of developing persistent phantom limb pain. This study is designed as a randomized controlled multicentric double blind trial, in which the effectiveness of applying a 5% lidocaine patch for 6 weeks will be compared with a sham.
Interventions
DRUGLidocaine
OTHERSham
Sponsors
Brugmann University Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* All above or below knee amputations , two months or more after surgery, after complete wound healing (no clips, no stitches, no seepage)
Exclusion criteria
* History of central nervous system disease * History of major psychiatric disease (MMS\<23/30, HADS\>8/21) * Pregnancy * Known hypersensitivity to local anesthetics (lidocaine, bupivacaine, etidocaine, mepivacaine, prilocaine) * skin irritation on the stump
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Patient-reported overall daily pain intensity | Daily, starting seven days before patch placement (baseline) till six weeks after patch placement | The overall daily pain intensity (stump, scar and phantom pain combined) will be rated on a 0 to 100 visual analogue scale with anchors of 0 (no pain) to 100 (worst pain ever experienced). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Neuropathic pain | at baseline - 7 days before patch placement | Rated with the Neuropathic Pain Symptom Inventory |
| Pain (McGill) | at baseline - 7 days before patch placement | Rated by the Short-Form McGill Pain Questionnaire, sensitive to the effects of pain treatment. |
| Quality of life | at baseline -7 days before patch placement | Rated by the SF36 questionnaire |
| Neuropathic Pain (DN4) | at baseline - 7 days before patch placement | Screening for neuropathic pain, by using the DN4 questionnaire |
| Delay of dress of provisory prosthesis | From the day of the surgery till the day of the delivery of temporary prosthesis, for a maximum of 6 months | Number of days between surgery and delivery of temporary prosthesis |
| Cumulative analgesic consumption (morphine equivalents) | baseline -7 days before patch placement | Rated by the cumulative analgesic consumption score (CACS) |
| Phantom Limb Pain occurence | 6 months after patch placement | occurence of phantom limb pain |
| Sleep quality | baseline -7 days before patch placement | will be assessed with the Pittsburgh Sleep Quality index |
Countries
Belgium
Outcome results
None listed