Intro to phantom limb pain

PHANTHOM LIMB PAIN

Definitions

Phantom sensation: non painful sensation of the

missing limb

Phantom pains:is a noxious sensation where the

limb existed

Stump pain:is the pain that is restrictedto the

amputated site

Phantom Pain coined by Silas Weir Michel in 1892

Common descriptions of phantom pain

Incidence

50-80% of amputees feel pain in the missing limb.

begins immediately after the arm or leg has been removed and it may last for years.

In over half of the cases, the phantom limb sensations decrease gradually.

not related to age, sex, location of the amputation, or reason for the amputation (e.g. trauma vs. disease).

Onset and Duration

Several studies have shown that 75% of patients with PLP develop pain within the first few days after amputation.

One study of 58 amputees found incidence of PLP to be 72%, 65% and 59% after 1 week, 6 months and 2 years. (Jensen, et al 1985)

Another study of 56 amputees showed that although the incidence and intensity of pain remained constant, the frequency and duration of pain attacks decreased significantly. (Nikolajsen, et al 1997)

Phanthom Phenomena

Phanthom Limb Phanthom Pain Stump Pain Super added Phanthom Referred Phanthom

Sensation

60% and 80% of amputees experience PLP (Nikolajsen and Jensen., 2000)

Stump Pain

Somatic stump pain usually resolves as the wound heals

Can trigger Phantom painProlonged stump pain usually attributable to local

pathology – delayed wound healing, infection, surgical complications, poor prosthetic fit, neuromas, adherent scars

Late onset stump pain - neuromas, prosthetic fit, claudication, bony overgrowth, osteoarthritis , tumour recurrence

Phantom Pain vs Sensation

Phantom limb Sensation – almost universaldoesn’t correlate with pain reports

Non-painful phantom sensations of 3 types:Kinetic senstations (movement)Kinesthetic (size,shape,position)Exteroceptive (touch, pressure, temperature, itch,

vibration)

Refferred Phantom Sensation

Telescoping of the Phantom Limb

PLP Onset

Mostly onset immediately after amputation, some at two weeks. Rarely months later

1/3 maximal immediately post-op and generally resolved by 100 days

½ slowly peaked then improved within 100 days¼ slower rise toward maximal pain

(Weinstein, 1996)

Prognosis

When PLP persists 6 months, prognosis for spontaneous improvement is poor

Probably <10% have persistent severe pain

Sensations felt by an amputee

A Little Man on the top

Mechanisms of Phantom Pain

Following a nerve cut, formation of neuromas are seen, which show spontaneous and abnormal evoked activity following mechanical and chemical stimulation. (Amir, et al 1993)

Percussion of stump/neuromas induces stump and PLP; increased activity of afferent C fibers (Nystrom, et al 1981)

Spinal Plasticity

After nerve injury, C-fibers and A delta-afferents gain access to secondary pain signaling neurons . This is manifested by mechanical hyperalgesia and expansion of peripheral receptive fields. (Doubell, et al 1999)

Increased activity of NMDA receptor; central sensitization can be reduced by NMDA antagonists such as ketamine. (Eichenberger, et al 2008)

Anatomical reorganization

Peripheral nerve damage can lead to degeneration of C-fiber afferent terminals in laminae II.

As a result, central terminals of Aβ-mechanoreceptive afferents (which normally terminate in laminae III and IV) sprout into laminae I and II. (Woolf, et al 1992)

Ultimately, this results in increased general excitability of spinal cord neurons.

Sympathetic nervous system role

Application of norepinephrine or activation of post-ganglionic sympathetic fibers excites and sensitizes damaged (not normal) nerve fibers. (Devor, et al 1994)

Sympatholytic block can abolish neuropathic pain, but pain can be rekindled by injection of norepinephrine under the skin. (Torebjork et al 1995)

Cerebral reorganization

One study of adult monkeys revealed cortical reorganization in which the mouth and chin invade cortices corresponding to arm and digits. (Dotrovsky, et al 1999)

In humans, similar reorganization has been observed using magnetoencephalographic techniques and there was a linear relationship between pain and degree of reorganization (flor, et al 1998)

Sussman (1995)

Assessment Tools

Visual Analoque ScaleUniversal Pain ScoreMacgill Pain QuestionaireFunctional Independence Measure

Treatment: A Multidisciplinary Approach

Treatment Approach

Non-Medical and Medical/SurgicalPrevent contracturesLimit oedemaAdequate Post-op AnalgesiaDesensitisation - massage/bandagingGet patient moving, distraction helpsEarly prosthetic training

Treatment Options

TENS/Ultrasound/MassageVibration TherapyAcupunctureRelaxation techiniquesBiofeedbackProsthesis trainingSensory discrimination trainingElectroconvulsive TherapyMirror TreatmentCognitive Behavioural Therapy

(Conine 1993)

TENS

Topographically relavant afferent signals from intact limb through transcallosal fibres activates cortical

area which acts as afferent input from missing limb (Orazio, 2010)

PARAMETERS:

Type: Conventional or Burst TENS

Pulse Frequency: 10-200 pps

Pulse duration: 100-250 ms

Area of application: Over stump, Contralateral limb, main nerve bundle, dermatome, across spinal cord, auricles

(Mark Johnson,2009)

BEST POSITION: Contra lateral TENS application????

(Winnem, 1982)

Mirror Box therapy

Ramachandran created a method of using mirrors to provide the brain with the missing visual stimulation.

The reflection of the intact limb is optically superimposed on the location of the amputated limb (Phantom Limb), tricking the brain into thinking that the Phantom Limb is real.

“MIRROR NEURONS”

Principle for MT

Visual feedback as a substitution for missing proprioceptive feedback will reduce pain

To fool the brain and to achieve normal interaction between motor intention to move the limb and the sensory feedback through mirror

(Ramachandran, 2000)

How to use mirror box

A box with mirror on sides is placed in front of the client.

The normal leg is placed on the side of the box in such a way to see it’s reflection on the mirror.

Then client is asked to move his/her normal limb

Daily use of the mirror for 30 min/day is beneficial

Exercise Protocol for MT

Brodie et al(2003) explained the procedures of the exercises to be performed

Duration of exercising 20 minutes daily(Serin et al 2013)

Neuromas

 Localized pain, sharp/shooting/paraesthesiaReproduced by local palpation, relieved by LA

injectionSocket correction and local steroid/LA injectionPhenol alcohol injection into neuromaSurgery – not much evidence, high recurrence rateULTRASOUND/TENS/SENSORY

REINTEGRATION TECHNIQUES

Managing Phanthom Pain

Daily 30 minutes of MBT TENS over stump/normal extermityWeight bearing on the stump using temporary

prosthesisMassageSensory integration techniuesRelaxation techniquesStump Strengthening exercisesProper positioning of stumpApplying crepe bandage to the stump

Pre operative PT role is crucial..!

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