2 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)
3 Overview Australian data – diabetes related lower limb amputations per year- 2:1 male: female ratio- majority in the year age group- Highest incidence in SA and NT (MJA 2000)
4 Indications for amputation: PVDFailed revascularisationExtensive tissue lossUnreconstructableExcess surgical risk
5 Indications for amputation: DiabetesOverwhelming sepsisExtensive tissue lossExcess surgical risk
6 Indications for amputation: TraumaCrushNerve injuriesOthersSpina bifidaContracturesNeuropathyBed bound
7 Goals of amputation:Get rid of all infected, necrotic and painful tissueAttain successful wound healingHave an adequate stump for a prosthetic
8 Attempt limb salvage or primary amputation? Extent of tissue loss in footAnatomy of reconstructionAssociated comorbiditiesESRD with heel gangrene – maybe best treated with primary amputation
9 Natural history of major amputation: 10% perioperative mortality3 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)
10 Amputation levels and significance: Major amputation: above tarso metatarsal joint.Levels- BKA- Through knee- AKA- Hip disarticulation
11 Amputation levels and significance: BKA – maximal rehabilitation potential% increase in energy expenditure% of all BKAs go onto an AKA in 3 years (5% periop mortality)AKA – less rehab potential% extra energy expenditure- Better rates of healing
12 Level Selection: Subjective: Clinical exam – skin quality, extent of ischemia/ infectionPulses – 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.The need to maximize rehab potential and minimize need for revision has led to the investigation of optimal method of level selection.
13 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.
14 Level Selection: Objective tests: Non invasive Doppler pressures – maybe unreliable in diabetics; ankle pressures >60mm – >50% chance of BKA healing.
15 Level Selection Non invasive 2. Skin perfusion pressures Radio isotope washoutLaser doppler velocimetry<20mm Hg – 89% failure of healing
16 Level Selection Non Invasive 3. Transcutaneous oximetry Tested under local hyperthermiaCorrelates with true PaO2Threshold value – 30mm