1. Lower Limb Amputations – Level Selection
Arvind Lee
Vascular Fellow
Nepean Hospital

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:
PVD
Failed revascularisation
Extensive tissue loss
Unreconstructable
Excess surgical risk

5. Indications for amputation:
Diabetes
Overwhelming sepsis
Extensive tissue loss
Excess surgical risk

6. Indications for amputation:
Trauma
Crush
Nerve injuries
Others
Spina bifida
Contractures
Neuropathy
Bed bound

7. Goals of amputation:
Get rid of all infected, necrotic and painful tissue
Attain successful wound healing
Have an adequate stump for a prosthetic

8. 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

9. 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)

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/ 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.
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 washout
Laser doppler velocimetry
<20mm Hg – 89% failure of healing

16. Level Selection Non Invasive 3. Transcutaneous oximetry
Tested under local hyperthermia
Correlates with true PaO2
Threshold value – 30mm

17. Level Selection:
Invasive – Angiographic scoring
Poor correlation

18. Level Selection

19. 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

20. Case 1 93 yr old from NH Bed bound after stroke
Painful heel ulcer on stroke affected side
Palpable popliteal pulse

21. Case 2 68 yr old male CRF on hemodialysis
Post surgery for #NOF – bilateral heel ulcers
Painful, non healing despite multiple debridements
Palpable popliteal pulses