1. Phantom Sensation/Pain
By JOSIP SULENTIC

2. Pain theory
Painful stimulus - also known as nociception, target nociceptors (which are sensory fibres) that are divided into 2 categories
A/delta fiber nocicpetors – myleinated, fast transmission of signals, characterised by well localised “sharp” pain
C fiber nociceptors – unmyleinated, slow, poorly localised pain - ”burning and throbbing” pain
Substance P (Pain neurotransmitter) released at the synapse between the nociceptors and the second order neurons
These neurons ascend to the brain via the spinothalamic tract to the thalamus
Message transmitted from the spinothalmic tract to the somatsensory cortex/homunculus ie. the area of the brain that is involved with coritical representation of the body i.e. the homunculus

3. Phantom Sensation
Any sensory phenomenon that is felt in the absent limb or a portion of it.
Up to 98% of amputees feel phantom sensation following an amputation
Phantom sensation is felt by spinal cord injuries, amputees (congential, vascular, trauma etc)
Types include:
- Sensations of movement
- Sensations of temperature, touch, pressure and itchiness
- Sensations of limb position, length (telescoping) and volume
Sensation of movement – feeling that the phantom limb is moving
Sensation of temperature
Sensation of limb position – feeling that the limb is in certain position with a certain functional activity i.e. the the knee is bent in the phantom knee when the patient is sitting etc. Telescoping is where the amputee feels that the limb is shortening over time

4. What is Phantom Pain?

5. What is Phantom Pain?
“True phantom limb pain is a complex, poorly understood pain syndrome that is described as burning, aching, or electric-type pain in the amputated limb . The diagnosis of phantom pain should only be made after other causes of stump pain have been eliminated including ischemia, infection, neuroma, and pressure-related wounds.”
Phantom Pain is almost exclusive in amputees. Whereby amputees feel phantom sensation with PAIN. Spinal cord injury patients can feel phantom sensation WITHOUT pain.

6. Incidence of Phantom Pain
Varies in literature – ranging from 5% to 85% - depending on diagnostic criteria that is used to define phantom pain. At Westmead, all my patients have at one point complained of phantom pain.
Poor control of pain and preoperatively and postoperatively may lead to an increase in chronic phantom pain.
Trauma vs vascular – Evidence suggests there is little difference between the 2 in terms of intensity. However, clinically, traumatic patients have reported greater intensity of phantom pain than vascular patients.

7. Pathophysiology
No certain explanation regarding pathophysiology but theories that are currently accepted are:
1. Peripheral mechanisms i.e. neuromas
Neuromas formed from injured nerve endings at the stump site are able to fire abnormal action potentials, and were historically thought to be the main cause of phantom limb pain. Although neuromas are able to contribute to phantom pain, pain is not completely eliminated when peripheral nerves are treated with conduction blocking agents.[5] Physical stimulation of neuromas can increase C fiber activity, thus increasing phantom pain, but pain still persists once the neuromas have ceased firing action potentials. The peripheral nervous system is thought to have at most a modulation effect on phantom limb pain.[3]

8. Pathophysiology Spinal mechanisms
in addition to peripheral mechanisms, spinal mechanisms are thought to have an influencing role in phantom pains. Peripheral nerve injury can lead to the degeneration of C fibers in the dorsal horn of the spinal cord, and terminating A fibers may subsequently branch into the same lamina.[3] If this occurs, A fiber inputs could be reported as noxious stimuli. Substance P, involved in the transmission of pain signals, is usually expressed by Aδ and C fibers, but following peripheral nerve damage, substance P is expressed by Aβ fibers.[3] This leads to hyperexcitability of the spinal cord, which usually occurs only in the presence of noxious stimuli. Because patients with complete spinal cord injury have experienced phantom pains, there must be an underlying central mechanism responsible for the generation of phantom pains.

9. Pathophysiology 2. Central mechanisms Central mechanisms
dThe somatosenory cortex relays information to the homunculus, this does not cease once the nerve is severed as a result of an amputation and thus phantom limb sensation can continue to affect the patient. A theory exists that afferent inputs from the surrounding areas will grow into that area and thus gain a larger representation in the homunculus, how long this takes is uncertain.

10. Management of Phantom Pain

11. Pharmacological
Evidence shows that preemptive epidural analgesia or PCA 48 hours prior to amputation and 48 hours post amputation can lead to a significant decrease in phantom pain 6 months after the amputation.
Morphine, gabapentine and ketamine show favourable results in the short term.
Limited evidence for effects of opioids on chronic phantom pain (however, this is often prescribed for patients by the treating team).

12. Mirror therapy
Among these 20 studies, 5 were randomized controlled trials (163 patients), 6 prospective studies (55 patients), 9 case studies (40 patients) and methodologies were heterogeneous. Seventeen of the 18 studies reported the efficacy of MT on PLP, but with low levels of evidence. One randomized controlled trial did not show any significant effect of MT. As to the effect of MT on PLM, the 8 studies concerned reported effectiveness of MT: 4 with a low level of evidence and 4 with a high level of evidence. An alternative to visual illusion seems to be tactile or auditory stimulation. Conclusion: We cannot recommend MT as a first intention treatment in PLP. The level of evidence is insufficient. Further research is needed to assess the effect of MT on pain, prosthesis use, and body representation, and to standardize protocol

13. Mirror Therapy cont’d
Systematic review = 20 studies = 5 RCTs + 6 prospective studies + 9 case studies
Results
17/18 studies showed low level evidence on the efficacy of Mirror Therapy on Phantom Limb Pain
1 RCT showed no significant effect of mirror therapy on Phantom Limb Pain
8 studies showed significant effects of mirror therapy on phantom limb movement, 4 low level evidence + 4 high level evidence.

14. Visualisation techniques

15. Visualisation techniques cont’d
RCT of 20 bilateral amputees with Phantom Pain divided into 2 groups
Group 1: n – 11 mentally visualising the movement
Group 2: n – 9 patient facing the experimenter perform 7 discrete movements whilst the amputee mentally copied the movement for 20 mins/day for 1 months.
7 movements were
Abduction and Adduction of the great toe, Flexion and extension of the ankle, inversion and eversion of the ankle, flexion and extension of the toes, rotation of the ankle and knee flexion and extension (for AKAs)
Subjects in the visual observation group experienced pain for 7.2 ± 5.7 months, while subjects in the mental visualization group experienced pain for 4.2 ± 5.3 months (P = 0.26). Participants demonstrated significant differences in pain severity at baseline for right and left limbs based on their treatment assignment, with participants assigned to the visual observation group reporting more severe PLP prior to treatment than those assigned to mental visualization. This discrepancy prevented comparison of the two treatment effects, so each treatment was assessed separately.

16. Visualisation techniques

18. Muscle relaxation, MI and Phantom Xs
INTERVENTIONS: The experimental group performed combined training of progressive muscle relaxation, mental imagery, and phantom exercises 2 times/wk for 4 weeks, whereas the control group had the same amount of physical therapy dedicated to the residual limb. No pharmacological intervention was initiated during the trial period. MAIN OUTCOME MEASURES: The Prosthesis Evaluation Questionnaire and the Brief Pain Inventory were used to evaluate changes over time in different aspects (intensity, rate, duration, and bother) of PLS and PLP. Blind evaluations were performed before and after treatment and after 1-month follow-up. RESULTS: The experimental group showed a significant decrease over time in all the Prosthesis Evaluation Questionnaire domains (in terms of both PLS and PLP; p < 0.04 for both) and the Brief Pain Inventory (p < 0.03). No statistically significant changes were observed in the control group. Between-group analyses showed a significant reduction in intensity (average and worst pain) and bother of PLP and rate and bother of PLS at follow-up evaluation, 1 month after the end of the treatment. CONCLUSIONS: Combined training of progressive muscle relaxation, mental imagery, and modified phantom exercises should be taken into account as a valuable technique to reduce phantom limb pain and sensation. 

19. Muscle relaxation, MI and Phantom Xs
RCT unilateral amputees with phantom pain or sensation
1. Experimental group n=27 = Progressive mm relaxation exercises i.e. moving the mind through different regions of the body to re-establish contact with it. Imagined movements – copy position of phantom limb to intact limb and then move in opposite direction and treturn to start – repeated 15 times or until phantom pain disappeared 2 times a week for 4/52
2. Control group n=24 = general Xs program in addition to standard physical therapy, Xs included strengthening, stretching, dynamic isometric Xs for the residual limb.

20. Results

21. Acupuncture
Of 24 amputees meeting the study inclusion criteria, 15 agreed to participate (recruitment rate 62.50%). Qualitatively, acupuncture was perceived to be beneficial and effective. Quantitatively, acupuncture demonstrated clinically meaningful change in average pain intensity (raw change 2.69) and worst pain intensity (raw change 4.00). Feasibility-specific data identified that before undertaking a definitive trial, recruitment, practitioner adherence to the acupuncture protocol, completion of outcome measures at 1 month follow-up and blinding should be addressed. Appropriate outcome measures were identified for use in a definitive trial. Data were generated for future sample size calculations (effect size 0.64). Allowing for a 20% dropout rate, a sample size of 85 participants per group would be needed in a future definitive trial. CONCLUSIONS: A future definitive trial may be possible if the areas identified in this study are addressed. As acupuncture may be effective at treating PLP, and as this feasibility study suggests that a definitive trial may be possible, a multicentred trial with adequate sample size and blinding is now needed.

22. Acupuncture cont’d RC feasibility study
24 Amputees included, 15 particpated, 8 males, 7 females (8 vascular, 4 Trauma, 3 other), 6 AKAs, 9 BKAs
Control = usual care = pharmacological intervention
Experimental group = followed TCM British guidelines – mirroring local and distal points by needling the intact limb = 8 session for 1 hour x 2/week for 4/52. Needles in situ for mins

23. Acupuncture results NRS (VAS) scores = Control 5.43 to 4.43
Experimental 5.44 to 2.75
Cohen’s different size = 0.64 ~ medium to large effect bw groups
Significant differences were recorded in NRS (VAS)
Patients perception of effect of therapy was increased in the treatment group.

24. Weird stuff
A true noninvasive limb cover did not significantly decrease PLP levels or the frequency of PLP episodes per week, overall bodily pain levels, or VR-12 physical and mental health component scores compared with a sham noninvasive limb cover in our veteran amputee sample

25. Weird stuff cont’d
RCT, 57 subjects, upper and lower limb amputees with a healed residual limb who had 3 or more episodes of phantom pain in the last 3 months.
Experimental = n = 30, wore the Farabloc limb cover over the prosthesis and wore the cover over the residual limb when the prosthesis was taken off. The cover was worn for 24 hours a day, 7 days a week for 12 weeks
Control = n = 27, wore sham cover for the same period of time.
Results – non significant reductions in phantom pain for both groups. Phantom pain scores were comparable in both groups.

26. Practice at Westmead
Combination of pharmacological and non-pharmacological treatments.
Motor functional empathy
Left/Right discrimination
Visualisation techniques
Mirror Therapy
Neural glides
TENS machine

27. Mirror therapy
Imagining L/R movements
L/R discrimination, recognise/orientate apps
Noi
Watching someone do the movement

28. Motor functional empathy

29. Left/Right discrimination

30. Explicit MI/Visualisation techniques
Smiling mind – free app. Utilises mindfullness techniques to ‘explore’ the lost limb and alleviate pain. This worked well on a patient of mine who sustained a traumatic amputation following a MBA.
Orientate – free app. Orientation of Left and Right with either the hand or foot

31. Mirror therapy

32. Neural glides

33. Tens machine

34. References
Alviar, M.J., Hale, T. and Dungca, M., Pharmacologic interventions for treating phantom limb pain. Cochrane Database Syst Rev, 12.
Hsiao, A.F., York, R., Hsiao, I., Hansen, E., Hays, R.D., Ives, J. and Coulter, I.D., A randomized controlled study to evaluate the efficacy of noninvasive limb cover for chronic phantom limb pain among veteran amputees. Archives of physical medicine and rehabilitation, 93(4), pp
Tung, M.L., Murphy, I.C., Griffin, S.C., Alphonso, A.L., Hussey‐Anderson, L., Hughes, K.E., Weeks, S.R., Merritt, V., Yetto, J.M., Pasquina, P.F. and Tsao, J.W., Observation of limb movements reduces phantom limb pain in bilateral amputees. Annals of clinical and translational neurology, 1(9), pp
Brunelli, S., Morone, G., Iosa, M., Ciotti, C., De Giorgi, R., Foti, C. and Traballesi, M., Efficacy of progressive muscle relaxation, mental imagery, and phantom exercise training on phantom limb: a randomized controlled trial. Archives of physical medicine and rehabilitation, 96(2), pp
Trevelyan, E.G., Turner, W.A., Summerfield-Mann, L. and Robinson, N., Acupuncture for the treatment of phantom limb syndrome in lower limb amputees: a randomised controlled feasibility study. Trials, 17(1), p.519.
Ephraim PL, Wegener ST, MacKenzie EJ, et al. Phantom pain, residual limb pain, and back pain in amputees: results of a national survey. Arch Phys Med Rehabil 2005; 86:1910.
Barbin, J., Seetha, V., Casillas, J.M., Paysant, J. and Perennou, D., The effects of mirror therapy on pain and motor control of phantom limb in amputees: A systematic review. Annals of physical and rehabilitation medicine, 59(4), pp