Pain Management for Amputees

1
Pain Management for Amputees

• Dr Craig Davenport
• Rehabilitation Registrar
• Liverpool Hospital
• 19th August 2005

2
Pain in the Amputee

• Pre-operative pain ischaemic, infection, trauma
• Early Post-op pain somatic vs neuropathic,
  stump vs phantom limb
• Late post-op pain stump vs phantom limb

3
Stump Pain

• Somatic stump pain usually resolves as the wound
  heals
• Can trigger Phantom pain
• Prolonged 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

4
Phantom Pain vs Sensation

• Phantom limb Sensation almost universal
• doesnt correlate with pain reports
• Non-painful phantom sensations of 3 types
• Kinetic senstations (movement)
• Kinesthetic (size,shape,position)
• Exteroceptive (touch, pressure, temperature,
  itch, vibration)

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Phantom Limb Pain

• Phantom pains often described as crushing, toes
  twisting, hot iron, burning, tingling, cramping,
  shocking, shooting, pins needles
• Tends to localise to more distal phantom
  structures (eg fingers and toes)
• prevalence in early stages 60-80
• Independent of age in adults, gender, level or
  side of amputation

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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 days
• ¼ slower rise toward maximal pain (Weinstein,
  1996)

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PLP Natural History

• Tends to diminish in severity and frequency over
  time, with resolution over several weeks to 2
  years
• One study 72 at 8 days, 65 at 6 months, 59
  at 2 years (Jensen, 1985)
• Duration of episodes vary - continuous 12, days
  2, hours 37, seconds 38 (Sherman
  Sherman,1983)
• 50 had decreasing PLP with time
• 50 no change or increase over time (Sherman et
  al, 1984)

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PLP Natural History

• Stump pain intensity tends not to correlate with
  PLP intensity
•  
• 2/3 experience telescoping of phantom limb
•  

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Also in Kids

• PLP also occurs in children, often
  under-recognised
• 70-75 at 7 years after amputation, but none
  severe (Boyle et al, 1982)
• Less in congenital limb deficiency

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Why does pain occur?

• Peripheral neuropathic mechanisms
• immediate nerve injury discharge
• local nociceptive substances
• deafferentation
• ectopic firing
• neuromas
• Ephatic transmission b/w sensory and sympathetic
  fibers

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Why does pain occur?

• Spinal cord
• Expansion of receptive fields
• Low-threshold inputs when high-threshold inputs
  lost
• Disinhibition
•  
• Brain
• Cortical engram generates pain in absence of
  stimuli
• Cortical reorganisation

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Why does pain occur?

• Non-neurological factors
• Skin blood flow
• Stump temperature
• Muscle tension
•  
• Psychological factors
• Stressors/ depression/ anxiety
• Not personality types

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Treatment Approach

• Non-Medical and Medical/Surgical
• Prevent contractures
• Limit oedema
• Adequate Post-op Analgesia
• Desensitisation - massage/bandaging
• Get patient moving, distraction helps
• Early prosthetic training

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Treatment Approach

• Somatic Pain non-pharm, simple analgesics,
  NSAIDs, tramadol, opioids
• Neuropathic/Phantom Limb Pain follow
  neuropathic pain principles Non-pharm, TCAs,
  anticonvulsants, local anaesthetics

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Non-Medical Treatments

• TENS
• Vibration Therapy
• Acupuncture
• Hypnosis
• Biofeedback
• Electroconvulsive Therapy
• Mirror Treatment
• Cognitive Behavioural Therapy
• Farabloc (Conine 1993)

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Peripheral Stimulation

• Controlled trial of TENS/sham/largactil showed
  benefit at 16 weeks no difference beyond 12
  months, improved stump healing (Finsen,1988)
• Auricular TENS controlled trial showed
  beneficial (Katz, 1991)
• Vibration Acupuncture only case reports

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Potential Drug Treatments

• Epidural anaesthesia
• Amitriptyline (Tricyclic antidepressants)
• Anticonvulsants carbamazepine, gabapentin
• Clonazepam
• Opioids/Tramadol
• Mexiletine/lignocaine
• Beta/alpha blockers - clonidine
• Intrathecal opioids/ lignocaine
• Capsaicin cream, NSAID cream
• IV Ketamine
• Sympathetic ganglion block

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Pre-emptive Analgesia

• Pre-operative anaesthesia
• Early trials looked promising but less robust
• Better designed trials did not show benefit in
  PLP (Nikolajsen 1997)
• Peri-op regional nerve blocks decreased use of
  opioids in early post-op period (Pinzer,
  1996)(Fisher, 1991)

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Amitriptyline (Endep)

• Well documented for neuropathic pain (Kingery,
  1997)
• Generally considered effective
• Dose 10mg up to 150mg (75mg in elderly)
• Recent RCT in PLP ? no benefit (Robinson 2004)

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Other TCAs

• Nortryptiline
• Imipramine
• Doxepin

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Gabapentin (Neurontin)

• Evidence in neuropathic pain
• RCT in PLP benefit at 6 weeks (Bone 2002)
• 100mg tds up to 1200mg tds
• Relatively well tolerated
• Main side effects are dizziness/somnolence/memory
  impairment
• Not subsidised by PBS for pain ? 150/mth

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Other Anticonvulsants

• Carbamazepine (Tegretol) cheap proven in
  neuropathic pain, nasty haematological S/Es
• Lamotrigine (Lamictal) emerging evidence for
  neuropathic pain
• Valproate (Epilim) lacks evidence, not very
  effective

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Others

• Capsaicin no RCT for PLP unpleasant
• IV calcitonin (post-op) unknown mechanism
  reduced early PLP, longer term effect lacks
  evidence (Jaeger, 1992)
• Mexiletine open label study in PLP risk of
  sudden death
• Beta-blockers limited reports
• Benzodiazepines clonazepam limited reports
• IV Ketamine reduces wind-up short-term
  reduction in PLP (Nikolajsen 1996)
• Opioids probably have a role
• Tramadol alternative to opioids
• NSAIDs not effective

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Pain and Prostheses

• Use of Prosthesis may increase or decrease pain
• Poor prosthetic fit may irritate stump tissues or
  neuroma ? revise socket
• Musculoskeletal pain due to altered biomechanics
  ? PTK/thigh lacer
• Sensitive stump may require altered prosthetic
  prescription ? Silicon liner, Thigh Lacer
• Stump bandaging/ hard casting may reduce pain

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Neuromas

•  localized pain, sharp/shooting/paraesthesia
• Reproduced by local palpation, relieved by LA
  injection
• Tinels sign
• Try socket relief and local steroid/LA injection
• Ablation Phenol alcohol injection into neuroma
• Surgery not much evidence, high recurrence rate
•  

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Nasty Interventions

• Stump surgery for defined pathology ? bury
  nerve terminal in bone, excise bony spurs
• DREZ lesioning
• Sympathectomy conclusive evidence lacking
  (Mailis 2003)
• Spinal cord stimulation works but expensive,
  infection risk
• Deep Brain or Motor Cortex Stimulation works
  but effect decreases with time
• Cordotomy/thalamotomy

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Prognosis

• When PLP persists 6 months, prognosis for
  spontaneous improvement is poor
• Probably lt10 have persistent severe pain

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References

• Bone et al, Reg Anaesth Pain Med,
  200227(5)481-6
• Boyle et al, Oncology, 198210301-312
• Conine et al, Can J Rehab, 19936155-61
• Finsen et al, J of Bone Joint Surg
  Br,198870109-12
• Fisher et al, Anaesth Analg, 199172300-3
• Halbert et al, Clin Journal of Pain, 2002
  1884-92
• Jaeger et al, Pain , 19924821-7
• Jensen et al, Pain, 198521267-78
• Katz et al, J of Pain Symp Man, 1991 673-83
• Kingery, Pain, 199773(2)123-39
• Levy et al, APMR, 2001 82(Suppl 1)S25-30
• Malis et al, Cochrane database of Systemmatic
  Reviews, 2003(2)CD002918
• Nikolajsen et al, Pain, 19966769-77
• Nikolajsen et al, Lancet,19973501353-7
• Pinzur et al, J Bone Joint Surg Am,
  1996791752-3
• Robinson et al, APMR,2004851-6
• Sherman et al, Pain,19841883-95
• Sherman Sherman, Am J of Phys Med,
  198362227-38
• Weinstein, 8th World Congress on Pain, 1996 pg376