1. Morning Report
Steven Hart

2. HPI 45 year old female presents to clinic to establish new PMD
CC: left leg pain
Recent medical history
Pain in left LE for 1 mo with several visits to ER
left femoral thrombus and emboli to left lower extremity eventually diagnosed
Left AKA required
Now (6 weeks later) c/o persistent pain where lower left leg was and sensations in left leg.
Started on coumadin prior to discharge

3. Physical exam C/w left AKA Exam otherwise unremarkable
Incisions clean and healing well
Non-tender, no erythema, skin intact
Exam otherwise unremarkable

4. Topics Phantom Limb Pain (PLP) Definitions Epidemiology
Etiology / Pathophysiology
Evaluation / Differential
Treatment
Prevention / Short term
Long term

5. Definitions Stump pain Phantom Limb Pain (PLP)
Pain in the residual portion of the limb
Phantom Limb Pain (PLP)
A painful sensation perceived in a missing limb after amputation
Phantom Limb Sensation (PLS)
Any sensation of the missing limb (paresthesia, dysesthesia, hyperpathia) except pain.

6. Epidemiology Phantom Limb Sensation (PLS)
Occurs in 85% - 98% of amputees within 3 weeks of amputation
8% may occur after 1-12 months
Usually resolves after 2 – 3 years spontaneously if PLP does not develop
Location affects intensity and likelihood of PLS
Proximal ie. Above the knees or elbows
Dominant extremity

7. Epidemiology Phantom Limb Pain (PLP) 60-70% of amputes experience PLP
Location again an important factor
Proximal
68-88% hemipelvectomy
40-88% hip disarticulation
51% upper limb
20% AKA
0-2% BKA

8. Epidemiology Phantom Limb Pain (PLP) – continued Time
Occurs 1 week to decades after amputation
Pain onset after one year in < 10%
May diminish and eventually resolve with time
More likely, however, it will persist chronically
Pain in limb prior to amputation increases risk for PLP
Pains in other parts of the body
Headache
Joint pain
Sore throat
Abd pain
Back pain

9. Epidemiology Stump Pain Occurs in about 50% of amputees
Frequently associated with phantom pain

10. Etiology Neuromas Dominate theory until last 10-15 years
Irritation of the severed nerve endings
Inflammation resulted in anomalous signals to the brain perceived as pain.
Treatments included removal of nerve endings or further amputation.
Only resulted in temporary improvement
Eventually pain returned, frequently worse
Modern thought - One of many factors causing PLP

11. Etiology Neuroma – their role  mechanical/neurostimulation 
spontaneous and abnormal evoked activity 
 in sodium channel production 
 in sensitivity of neuromas to norepinephrine
Thus, pain with stress or other emotional states
A similar phenomenon occurs in the cell body of the dorsal root ganglia just upstream

12. Etiology -spinal cord level
 signal from neuromas and doral root ganglia cell bodies 
 activity of neurons in dorsal horns 
 upregulation of several genes
- especially receptive genes
-  in N-methyl-D-aspartate (NDMA)

13. Etiology -spinal cord level
Anatomical reorganization (rewiring)
Perph nerve transection  degeneration of afferent C-fiber terminals in Lamina II
These may replaced by A mechanoreceptive afferents
Results in pain evoked by simple touch

14. Etiology - Central mechanism
Somatosensory cortex remapping
PLS/PLP evoked by touching face in a hand amputee
Verified by multiple neuroimaging studies in humans

15. Etiology - Central mechanism
Plastic changes occur in the Thalamus
Stimulation of thalamus in amputees causes PLP and PLS
Similar stimulation does not cause any pain in non-amputees

16. Differential Diagnosis of PLP
Radicular pain
Disk herniation
Angina
Post herpetic neuralgia
Metastatic cancer
Infection / poor wound healing

17. Treatment of PLP -Overview
Poorly studied field
placebo effect common
Spontaneous resolution does happen
Fewer than 10% of PLP patients receive lasting relief
Frequently, neuropathic treatment recommended, but few studies to support this
Most neuropathic treatment trials do not include PLP
Prevention of PLP is a new area of interest

18. Treatment of PLP -Overview
Multiple approaches
Prevention
Medical
Physical Therapy
Nerve Blocks
Nerve stimulation
Transcutaneous, spinal cord, deep brain, motor
ECT
Psychological Therapy

19. Treatment of PLP -Prevention
Goal – avoid/control the changes that lead to chronic pain
Prevent or control pre, peri and post-operative pain
Use of pre, intra and post-op epidural blocks has been shown to reduce occurrence of PLP at 12 mo post-op
Mixed results in follow up studies

20. Treatment of PLP -Prevention
Calcitonin infusions
Ketamine
Transcutaneous electrical stimulation

21. Treatment of PLP -Medical Management
Anti-depressants
Tricyclic anti-depressants
Anti-convulsants
NMDA receptor antagonists
Opiates
Beta Blockers
Misc

22. Treatment of PLP -Medical Management
Tricyclic anti-depressants
Frequently used
Well studied in other neuropathic pain syndromes
Diabetes, post herpetic neuralgia
Poorly studied in PLP
One randomized study showed no effect, other studies showed some benefit

23. Treatment of PLP -Medical Management
Anti-convulsants
Carbamazepine
Effective for intense, brief, lancinating type of pain
Gabapentin
Effective in one small randomized trial
Topiramate
Small randomized study supported it effectiveness

24. Treatment of PLP -Medical Management
Opiates
Effective for both stump pain and PLP
May affect cortical reorganization
Considered the mainstay of treatment
Tolerance/Addiction
Most amputees have a short life expectancy because of underlying disease.
Balance quality of life vs risk of opiate addiction/dependence

25. Treatment of PLP -Medical Management
NMDA receptor antagonists
Ketamine – effective, must be IV
Memantine – oral, ineffective
Dextromethorphan
Small randomized studies have supported its use.
Improved feeling
No, small sedation
No increased side effects from placebo

26. Treatment of PLP -Physical Therapy
Sensory discrimination training
Designed to alter the cortical map
Shown to significantly reduce PLP and cortical reorganization

27. Treatment of PLP -Neurostimulation
Transcutaneous electrical nerve stimulation
Spinal Cord Stimulation
Deep brain stimulation
Motor cortex stimulation
All very preliminary

28. Treatment of PLP Acupuncture ECT Psychological Therapy
May provide short term relief
ECT
Several case reports of pain resolution after treatment
Psychological Therapy
Relaxation training
hypnosis

29. Conclusion PLP is common in amputees
The cause is complicated and involves virtually all levels of the nervous system
Prevention of chronic pain may be possible but further investigation is needed
Chronic pain management is difficult and should be multifaceted
There is little evidence to guide therapy at this time.