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Lower Limb Amputations – Level Selection. Arvind Lee Vascular Fellow Nepean Hospital. Overview. Integral part of any surgical practice. The global lower extremity amputation study group - wide variations in amputation rates worldwide - similarities in age and sex distribution - PowerPoint PPT Presentation
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Lower Limb Amputations – Level Selection
Arvind LeeVascular FellowNepean Hospital
Overview
• Integral part of any surgical practice.
• The global lower extremity amputation study group
- wide variations in amputation rates worldwide
- similarities in age and sex distribution - very high correlation with diabetes (BJS 2000)
Overview
• Australian data – - 2629 diabetes related lower limb
amputations per year - 2:1 male: female ratio - majority in the 65-79 year age group - Highest incidence in SA and NT (MJA 2000)
Indications for amputation:
• PVD- Failed revascularisation- Extensive tissue loss- Unreconstructable- Excess surgical risk
Indications for amputation:
• Diabetes- Overwhelming sepsis- Extensive tissue loss- Excess surgical risk
Indications for amputation:
• Trauma- Crush- Nerve injuries
• Others- Spina bifida- Contractures- Neuropathy- Bed bound
Goals of amputation:
• Get rid of all infected, necrotic and painful tissue
• Attain successful wound healing• Have an adequate stump for a prosthetic
Attempt limb salvage or primary amputation?
• Extent of tissue loss in foot• Anatomy of reconstruction• Associated comorbidities
• ESRD with heel gangrene – maybe best treated with primary amputation
Natural history of major amputation:
• 10% perioperative mortality• 3 year survival after BKA – 57%; after AKA –
39%• Of 440 major amputations – 75 died in
hospital, 113 deemed unsuitable for prosthesis. Of 57% referred for prosthesis – at 3years follow up a further 54 died, only 10-15% were mobile at home. (BJS 1992)
Amputation levels and significance:
• Major amputation: above tarso metatarsal joint.
• Levels - BKA - Through knee - AKA - Hip disarticulation
Amputation levels and significance:
• BKA – maximal rehabilitation potential - 10-40% increase in energy expenditure - 15-20% of all BKAs go onto an AKA in 3
years (5% periop mortality)• AKA – less rehab potential - 50-70% extra energy expenditure - Better rates of healing
Level Selection:
• Subjective:- Clinical exam – skin quality, extent of
ischemia/ infection- Pulses – presence of a pulse immedietly above
the level of amputation – almost 100% chance of healing
- “Clinical judgment” alone 80% accurate in predicting healing with BKA and 90% in AKA.
Level Selection:
• Wagner et al (J vasc surgery 1988): clinical judgment superior to objective assessments. More distal amputations can be achieved with clinical measures over objective studies.
• Clinical judgment is central to amputation level selection.
Level Selection:
• Objective tests:- Non invasive1. Doppler pressures –
maybe unreliable in diabetics; ankle pressures >60mm – >50% chance of BKA healing.
Level Selection
• Non invasive2. Skin perfusion
pressures- Radio isotope washout- Laser doppler
velocimetry- <20mm Hg – 89%
failure of healing
Level Selection
• Non Invasive3. Transcutaneous
oximetry- Tested under local
hyperthermia- Correlates with true
PaO2- Threshold value –
30mm
Level Selection:
• Invasive – Angiographic scoring
• Poor correlation
Level Selection
Conclusions:
• Amputation is traumatic enough…poor level selection can make it worse.
• Clinical judgement central to proper level selection
• Patient factors are more important than objective testing
Case 1
• 93 yr old from NHBed bound after strokePainful heel ulcer on
stroke affected sidePalpable popliteal pulse
Case 2
• 68 yr old maleCRF on hemodialysisPost surgery for #NOF – bilateral heel ulcersPainful, non healing despite multiple
debridementsPalpable popliteal pulses