A thorough yet efficient history should be obtained upon presentation to the hospital, as “time is tissue” in limb ischemia. Special attention should be paid to known heart disease, diabetes, heart failure, end-stage renal disease, peripheral arterial disease, and any interventions related to such. Comorbidities should be acutely managed in a multidisciplinary approach to optimize surgical outcomes. Preoperative cardiac risk stratification is recommended for all patients with a known cardiac history who face amputation. In the diabetic patient, blood glucose management below 200 mg/dL has been shown to significantly decrease perioperative complications and surgical dehiscence rates [1]. Inherited or medication-induced coagulopathy should be noted and corrected.

A focused vascular exam should begin with palpation and Doppler evaluation of femoral, popliteal, anterior/posterior tibial, and peroneal arteries. Patients with a history of bypass should be evaluated for graft patency. Abdominal exam should focus on identification of abdominal aortic aneurysms and auscultation for bruits. Skin perfusion may also be assessed by temperature, as there is often a transition in an ischemic limb. The level where there is a clear demarcation between warm and cool tissue should be noted. If the patient complains of ischemic pain, the level at which the pain ceases should also be demarcated. Both temperature change and pain often coincide. The lack of hair on the distal limb may also suggest the chronicity of peripheral vascular disease.

The vascular surgeon plays a critical role in the decision for limb salvage versus amputation. A preoperative angiogram should be obtained to evaluate potential bypass targets and endovascular interventions. Even in renal transplant patients, good studies can be obtained with minimal dye (<10 cc of dye). Review of previous angiograms or Doppler exams is also helpful in noting acute change and progression of disease. The presence and caliber of diseased or collateral vessels are paramount in determining the level of amputation that is most likely to heal.

Limb ischemia is frequently accompanied by soft tissue infections and osteomyelitis. This particular subset of patients typically has a history of multiple hospitalizations and surgical interventions, increasing their likelihood of carrying multidrug-resistant organisms. Thus, the antibiotic dosing and management in this patient population is complex and regimens should be culture directed. At the senior author’s institution, infectious disease is routinely consulted to aid in preoperative and, perhaps more importantly, postoperative antibiotic management .

Primary amputation in limb ischemia is neither the patient’s nor the provider’s preferred method of treatment. However, there are several clinical circumstances in which amputation should be strongly considered. The most important factor is to realistically assess the patient’s ultimate functional goal as well as the quality of function the patient will enjoy with a salvaged versus amputated limb. For example, a patient who wants to be able to live at home and carry out the acts of daily living might be very satisfied with a partial mid-foot and hindfoot amputation, while a more active patient may elect a below-knee amputation to be able to do what he/she wants to do. The decision then to salvage or amputate depends upon the resources available to the provider. Centers equipped for vascular bypass as well as angiography, intraoperative angiography and intervention, pedicled and microsurgical flaps, and external fixation or suspension have far more tools at their disposal for attempt limb salvage procedures than centers that do not have some of these options.

Previous literature suggests decreased life expectancy after amputation secondary to restricted mobility and the relative increased cardiovascular demand with ambulation with a prosthesis. However, the mechanism of increased risk of cardiovascular events in amputees has not been well studied [2]. Salvage of a nonfunctional foot can lead to deconditioning because of limited ambulation and can be a constant drain both on the patient’s physiologic and healthcare resources. Pell et al. showed that quality of life in amputees is associated with mobility and function, rather than length of lower extremity [3]. After reviewing our outcomes of 294 below-knee amputations at a major limb salvage center, 78 % of patients were ambulatory postoperatively [4]. With proper surgical technique, intensive rehabilitation, and the advancement of prosthetic technology, amputees have very good functional outcomes and quality of life.

Surgical planning in the setting of acute limb ischemia should be directed in optimizing long-term patient function. The level of amputation is multifactorial and depends upon the soft tissue availability, blood flow, infection status, and rehabilitation options as well as the available resources of the reconstruction team. In this chapter, below-knee amputation (BKA), BKA using the ERTL technique, knee disarticulation (KD), and above-knee amputation (AKA) will be discussed.

Preoperative medical management is of equal importance to surgical technique. Diabetes, end-stage renal disease, coronary artery disease, coagulopathy, and chronic anemia are associated with increased surgical complications and should be optimized. Patients with ESRD should have their potassium level checked on the day of surgery and dialyzed appropriately. Beta-blockers should be taken the morning of surgery and perioperative antibiotics should be current and re-dosed as needed.

The level of anesthesia may vary based on the planned procedure. The senior author prefers epidural anesthesia that can be kept in postoperatively. If it is started up to 48 h before surgery, it may help improve postoperative pain control. In this comorbid patient population, every attempt should be made to lower the risk due to anesthesia. However, a recent study by Lin et al. compared the 30-day mortality of general anesthesia to regional blocks following below-knee amputation. Their review of 156 patients revealed no difference in 30-day mortality between general anesthesia or spinal anesthesia [5]. In our recent experience, local injection of EXPAREL, a 72 h liposomal bupivacaine (Pacira, Parsippany, New Jersey), at the operation of the definitive amputation, also appears to provide improved postoperative pain control and aids in the transition of intravenous narcotics to oral pain control regimens.

The senior author prefers that amputations performed in the setting of infection should be done in two stages. The initial drainage amputation if the foot is involved is an ankle disarticulation. If the ankle is involved, a guillotine amputation is planned above the infection. The completion amputation is then performed at least 2–3 days afterward with negative pressure therapy dressing covering the amputated stump in the interim. Two-stage below-knee amputation for ischemic and infectious causes has been shown to have decreased reoperation rates [6]. It allows for limited cross contamination from the wound as well as tissue demarcation if there is suspected progression of soft tissue ischemia. In two-stage operations where massive edema is present in the leg, a lymphedema wrap is applied to the residual limb post-drainage amputation to decrease the edema and make the tissue more pliable for the definitive amputation.

The advent of fluorescent angiography is an additional tool in determining the level of soft tissue viability in amputation. The SPY (Novadaq, Vancouver, Canada) system has been commercially used for the evaluation of mastectomy flap viability in the setting of breast reconstruction. We have also utilized this technology at our institution for cases in which lower extremity soft tissue viability is uncertain. Intraoperative injection of 3–5 mL of indocyanine green allows for real-time identification of vascularized cutaneous angiosomes. This technology is currently being investigated in the planning of both the design of incisions and the level of amputation.

It also critical that the patient meets with a prosthetist preoperatively so that the patient fully understands what is about to occur. The prosthetist can give invaluable feedback to the surgeon so that the ideal residual limb can be designed. If possible, it is also very valuable if they can meet with another amputee who has gone through what the patient is about to experience. This pre-amputation consultation is invaluable not only in allaying the fears of the patient but also ensuring the most functional outcome.

Bickel popularized the use of the superficial posterior compartment myocutaneous flap in 1943. Burgess later modified it by recommending that the deep posterior compartment be removed to limit unnecessary bulk in the posterior flap and limit the amount of remaining tissue that is dependent on presumably diseased posterior tibial and peroneal arteries [7]. Interestingly, in popliteal or trifurcation disease, the sural arteries that feed the gastrocnemius muscles are usually spared and provide the necessary blood flow to the posterior flap. This is reflected in our series of 294 flaps where the ratio of BKA to AKA was 4:1 with a 2 % eventual conversion rate from BKA to AKA. Our institution uses a superficial posterior compartment myocutaneous flap in which the superficial posterior compartment provides vascularized and durable coverage of the tibial osteotomy (Fig. 53.1). Tenodesis and myodesis of the superficial posterior compartment have several functions. Gastrocnemius muscles continue to function as knee flexors and thus maintain bulk and prevent atrophy. A second benefit of the PMF is preventing a suture line and future scar over the distal stump. A final benefit is that the musculature still functions as a venous pump preventing lower leg edema.

The componentry below the socket in the average below-knee prosthesis requires at least 8 inches clearance from the ground. In addition, preserving extra length is critical as it allows increased leverage and it provides additional tissue for an adequate revision BKA should it ever be required. After consulting with the prosthetist, the senior author plans each BKA with a tibial osteotomy at 15–18 cm from tibial tubercle if there is adequate distal soft tissue. Otherwise the amputation is done no shorter than 12 cm from the tibial tubercle. The leg is elevated and the thigh tourniquet is inflated provided there is no counter-indication (e.g., recent femoral popliteal bypass). Coban is used to isolate the distal drainage wound or foot to prevent contamination of the field and proximal clean tissue.

An anterior skin incision is drawn 1 cm longer than the planned tibial osteotomy site, encompassing two-third the circumference of the leg. Medially and laterally the skin incision is carried inferiorly with a slight anterior slant toward the ankle (Fig. 53.2). The dissection of the anterior compartment is performed with electrocautery. Special attention is paid to preserve the lateral compartment that may be used for myodesis later. The anterior tibial artery is identified and suture ligated. Both peroneal nerves and saphenous nerve are marked and saved for future injection with local anesthesia and divsion under traction.

The tibia is exposed and the planned osteotomy is verified at preplanned distance. An army-navy retractor is passed posterior to the tibia and the osteotomy is made perpendicular to the longitudinal axis of the tibia. The fibular osteotomy is approximately 1 cm shorter with a bevel slightly oriented from lateral to medial (Fig. 53.3).

After both osteotomies , a bone hook into the open end of distal tibia provides anterior retraction to expose the deep posterior compartment. A 10 blade is used to sharply dissect the deep posterior compartment off the distal tibia and fibula (Fig. 53.4). The distal leg is then cut at a distance that guarantees sufficient distance to fold the posterior flap anteriorly to close the remaining leg. After removing the distal leg, the deep posterior compartment is dissected off of the superficial compartment (Fig. 53.5) and removed with careful ligation of the peroneal and posterior tibial perforators to the superficial posterior department. The posterior tibial and peroneal arteries are tied off, and the deep peroneal nerve and posterior tibial nerves are preserved for later injection with anesthetic subsequent proximal division under traction.

The anterior half of the tibial cortex is then beveled for about 1 cm using a sagittal saw (Fig. 53.6). The bevel is then sanded down by brushing the sagittal saw over that area. Three holes are drilled into the anterior tibia from the anterior cortex into the medullary canal and will be used for future tenodesis (Fig. 53.7).