Lower Limb Amputations – Presented by Letch Kline, M.D., FACS Thoracic/General Surgeon Gulf Coast Veterans Health Care System

Overview Integral part of general 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)

Limb Loss Statistics There are nearly 2 million people living with limb loss in the United States Approximately 185,000 amputations occur in the United States each year Nearly half of the individuals who have an amputation due to vascular disease will die within 5 years. Of persons with diabetes who have a lower extremity amputation, up to 55% will require amputation of the second leg within 2‐3 years

Indications for amputation: Peripheral Vascular Disease Failed revascularization Extensive tissue loss Unreconstructable Excessive surgical risk

Indications for amputation: Diabetes Overwhelming sepsis Extensive tissue loss Excessive surgical risk

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

Goals of amputation: Remove all infected, necrotic and painful tissue Achieve successful wound healing Fashion 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 tarsal-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% perioperative 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. The need to maximize rehab potential and minimize need for revision has led to the investigation of optimal method of level selection.

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 invasive Doppler pressures – maybe unreliable in diabetics; ankle pressures >60mm – >50% chance of BKA healing.

Level Selection Non invasive 2. Skin perfusion pressures Radio isotope washout Laser doppler velocimetry <20mm Hg – 89% failure of healing

Level Selection Non Invasive 3. 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 is central to proper level selection Patient factors are more important than objective testing

References: Lee, A. Vascular Fellow, Nepean Hospital. PPT presentation “Lower Limb Amputations: Level Selection” Ziegler‐Graham K, MacKenzie EJ, Ephraim PL, Travison TG, Brookmeyer R. Estimating the Prevalence of Limb Loss in the United States: 2005 to 2050. Archives of Physical Medicine and Rehabilitation2008;89(3):422‐9. Owings M, Kozak LJ, National Center for Health S. Ambulatory and Inpatient Procedures in the United States, 1996. Hyattsville, Md.: U.S. Dept. of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics; 1998. Robbins JM, Strauss G, Aron D, Long J, Kuba J, Kaplan Y. Mortality Rates and Diabetic Foot Ulcers. Journal of the American Podiatric Medical Association2008 November 1, 2008;98(6):489‐93. Pandian G, Hamid F, Hammond M. Rehabilitation of the Patient with Peripheral Vascular Disease and Diabetic Foot Problems. In: DeLisa JA, Gans BM, editors. Philadelphia: Lippincott‐Raven; 1998.