Chapter 111 - Lower extremity amputations - introduction Flashcards
What percentage of amputations as associated with diabetes
25-90%
Risk of amputation in diabetes
8x 1) neuropathy 2) infection 3) PAD
association in number of vascular surgeon and amputations
0.3 increase per 10000 = 1.6% reduction in amputation
Indication for amputation
1) acute ischemia 2) chronic ischemia 3) foot infection 4) trauma 5) malignancy
Indications for amputation by vascular surgeon
1) CLI with failed revasc 39% 2) extensive pedal gangrene 15% 3) non-reconstructable anatomy 11% 4) overwhelming pedal sepsis 9% 5) excessive surgical risk 9% 6) nonviable acute ischemia 8% 7) nonambulatory status 8%
WIfI scoring system categories
Wound Infection foot Ischemia
Delay to vascular surgery consultation for pedal tissue loss and rest pain
Tissue loss 73 days Rest pain 27 days
Current practice predictors for choosing amputation over revasc for CLTI
1) dm 2) esrd 3) tissue loss 4) poor functional status
5 perioperative stages to an amputation
Stage 1: pre-op decision to amputate; pre-op workup; surgeon in charge Stage 2: acute post-op 3-10 days; transition of care to rehab Stage 3: immediate post acute hospital; 4-8 weeks after surgery, recovery, wound heal, early rehab Stage 4: intermediate recovery; transition to first formal prosthetic device, begin ambulation; 4-6 months from healing date Stage 5: transition to stable stage; healing continues for 12-18 months after initial healing; visit prosthetist until 1 year of stability; move towards social reintegration
Mortality of major amputation
8% AKA may have double that of BKA
Complications following major amputation
1) stump complication 10% 2) CAD, VTE, CVA 0.5-2.1%
% of amputation-related death caused by PE
17%
Urgent amputation options
1) guillotine amputation 2) cryoamputation
Techniques of cryoamputation
1) dry ice 2) plastic bag 3) umbilical tape as tourniquet 4) towel blanket adhesive tape 5) heating pad can be maintained for weeks
Goals of amputation
1) eliminate infected, necrotic and painful tissue 2) to achieve uncomplicated wound healing 3) to have appropriate remnant stump to accommodate prosthesis
Extra energy expenditure required to ambulate after unilateral BKA and AKA
BKA 10-40% AKA 50-70% TABLE 111.3
Prosthetic use rate after BKA and AKA
BKA 50-100% AKA 10-30%
Rate of revising BKA to AKA
15-25%
Mortality in revising BKA to AKA
5%
Healing rate of BKA
80%
Healing rate of AKA
90%
Healing rate of BKA with palpable popliteal
~100%
Skin temperature to predict amputation heal rate
Amputation level skin > 90F has 80-90% chance of healing
Absolute ankle pressure to predict healing of BKA
ankle pressure > 60 = 50-90% healing of BKA
risk of needing amputation with an ABI > or < 0.5 in CLTI with wound
< 0.5: 28% 6 month, 34% 1 year > 0.5: 10% 6 month, 15% 1 year
Toe pressure that predict failure of minor amputation in diabetics
< 38 mmHg
Other methods of assessing amputatin healing likelihood
1) radioisotope scan 2) scintigraphy 3) skin perfusion presure 4) transcutaneous oxygen measurement (best)
Accuracy of transcutaneous oxygen
87-100% at prediction of wound healing failure when tcPO2 < 30 mmHg
Prediction of wound healing by non-invasive vascular studies
TABLE 111.2
Factors associated with poor ambulation postop
1) poor preop ambulation 2) age > 70 3) dementia 4) ESRD 5) CAD
Dressing types after BKA
1) soft gauze dressing with elastic wrap 2) thigh level rigid plaster 3) thigh level plaster with immediate postop prosthesis (IPOP) 4) short removable rigid plaster 5) prefabricated pneumatic IPOP IPOP may reduce rehab time not clear about post-op complication
Timing of NWB on stump after BKA
4-6 weeks
Types of AKA prosthetics
1) standard 2) intelligent prostheses with microprocessor
BKA prosthetics
1) standard passive ankle 2) energy conserving ankle 3) open type socket
Predictors of death: patients with AKA who were not ambulating pre-op
10x no prosthesis 2x mortality at 1 year
through knee amputation key points
1) need adequate residual skin and subcutaneous tissue 2) higher normal and max walking speed with lower energy expenditure than AKA 3) earlier weight bearing status with lower risk of wound complication than BKA
ambulation status for age < 60 and well-controlled comorbidities
if walking before post op ambulation 70% survival 80% independent living 90% at 1 year
Chance of controlateral limb amputation in 5 years in diabetic
15-35% higher risk if ESRD
