Lower Extremity Amputation

Every team performing a lower extremity amputation must include an operating room nurse, a scrub technologist, a surgical assistant, and an anesthesiologist. Post-anesthetic care unit staff is usually comprised of nurses and anesthesiologist or intensivists and are vital in the care of the patient in the immediate post-operative period. Face-to-face communication from the surgery team is obligatory during patient hand-off. This is an opportunity to communicate a summary of the patient and the reason for the operation performed. It also allows the surgeon to communicate adversities encountered during the case, report on estimated blood loss and discuss resuscitative measures used intra-operatively that may need continuation in the immediate post-operative setting. It is also important to communicate the type of hospital unit the patient will go to thereafter and the need for post-operative laboratory values. 

The most important part of the preparation, after medical optimization, is determining the level of amputation. Transcutaneous oxygen tension (TcPO2) is a measure of oxygen tension in the skin derived from the local capillary blood perfusion. This has been utilized as a tool to determine the level of amputation in ischaemic limbs which demonstrated that patients with primary healing of postoperative wounds had significantly higher values of TcPO2 than patients with failure to heal (37 mmHg; range 15 to 56 mmHg vs. 18 mmHg; range 8 to 36 mmHg, p<0.01).[8] Although useful in the setting of isolated peripheral vascular disease, this tool does not take into account the condition of the patient, the condition of the soft tissues, the presence of neuropathy or the functional status of the patient; all of which are also determinants in selecting amputation level. An accepted approach to amputation level determination in the patient with peripheral vascular disease is the presence of a femoral pulse; this indicates patency of the deep femoral artery which has general acceptance as appropriate for a transtibial (below-knee) amputation. On the other hand, efforts for revascularization must undergo an assessment before performing an above-knee amputation in the absence of a femoral pulse[9].  Despite many available modalities for assessing healing potential, none has proven more useful than a good physical exam.  Pulse, temperature, and hair growth patterns are all useful and guide clinical intuition.  

It is imperative to discuss the probability of independence after major lower extremity amputation with the patient. AMPREDICT is a user-friendly prediction tool of mobility outcomes in individuals undergoing major lower extremity amputation because of complications of diabetes or peripheral vascular disease.[10] Informing the patient of their probability to achieve independence in the 12 months following amputation allows for shared-decision making and, more importantly, allows the patient to understand their mobility prognosis during the strenuous recovery period.  Rates of ambulation outside the home decrease drastically as the length of amputation decreases.  Energy expenditure for ambulation increases significantly as the amputation site moves higher.   

More often than not, the level of amputation is determined by the degree of soft tissue compromise/infection despite optimal antibiotic therapy. In patients presenting with gangrene or necrotizing soft tissue infection, there is very little room for discussion, and the primary objective is to preserve life. A secondary objective in this setting is to preserve as much functional limb length as possible as this has a significant impact on the patients post-operative functionality. 

The use of general anesthesia (GA) versus regional anesthesia (RA) for performing major lower extremity amputation is an area of ongoing debate. There is literature to support the use of RA for major lower extremity amputation with decreased blood loss, need for transfusion, postoperative pain medication, and faster time to oral intake when compared with the general anesthesia group.[11] Another study showed there was no difference in postoperative myocardial infarction or mortality between GA and RA.[12] More recently, the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) was utilized to determine the effect of anesthesia type on major lower extremity amputation outcomes in functionally impaired elderly patients.[13] They reviewed over 3000 patients over eight years. Fifty-nine percent underwent above-the-knee amputations, and the remainder were below-the-knee. Patients undergoing GA were more apt to have impaired sensorium, be on anticoagulation, or have a bleeding disorder and had a prior operation within 30 days. GA correlated with shorter anesthesia time to surgery but equivalent operative times when compared to RA. There was no difference with regards to postoperative myocardial infarction/cardiac arrest, pulmonary complications, stroke, urinary tract infections, and wound complications. Therefore, the decision about which anesthesia type to use should be performed on a case by case basis and collectively between the patient, surgeon, and anesthesiologist. 

There are several components in the preparation of the patient in the operating room which apply to all amputation levels. The patient should be in the supine position with appropriate use of tourniquet as this has shown to reduce blood loss during lower extremity amputation in the setting of peripheral artery disease.[14] Preparation of the skin should be performed circumferentially and as proximal as the groin. Skin preparation products include those containing iodophors or chlorhexidine gluconate, both of which are acceptable options.[15] In the setting of diabetic foot wounds or gangrene, we recommend maintaining the wound covered with a dry dressing as well as covering the affected foot with a sterile impermeable stockinette. An occlusive adhesive dressing can be utilized to create a seal and further isolate this from the incision site. 

Principles of amputation surgery at any level includes: removal of diseased tissue, providing a residual limb that allows for prosthetic fit, tapering the ends of bone to avoid sharp edges, providing a conical shaped limb to allow better prosthetic fit, controlling postsurgical edema, avoiding hematoma formation, allowing for nerve retraction, preservation of length and optimized postoperative pain control.[16]

The critical steps in surgical technique for several amputations levels will be discussed in order of proximal to distal. 

1. Above-knee amputation
   1. The anterior and posterior flaps should be marked before incision to resemble an ellipse or fishmouth.  It is useful to measure the circumference and mark the apices equally.   If length is not an issue, the tip of the anterior flap should reach the edge of the patella with a mirror image posterior flap.
   2. Tourniquet and Esmark bandage is used.  An incision is carried through the fascia, and the anterior musculatures divided with cautery.
   3. The muscle gets divided to the level of the femur, and the periosteum elevated from the femur circumferentially to the level of the incision apex. 
   4. An oscillating saw or Gigli saw is used to divide the femur.  The adductor tendon is separated separately from the medial epicondyle and distal femur; this may be preserved for use in a myodesis. The edges are then rasped smooth.
   5. The femoral artery and femoral vein are clamped and suture ligated with heavy suture.
   6. The saphenous nerve should be dissected as proximally as possible and divided on tension.  It is this authors opinion that avoiding ligation helps avoid foreign body reaction and future neuroma formation. The nerve should retract 5 cm to 10 cm. 
   7. If performing a myodesis (preferred by this author), a 2 mm drill bit is used to make a medial and lateral osteotomy on the distal femur.
   8. The preserved adductor tendon is then secured to the osteotomies medially and laterally with heavy non-absorbable fiber-wire or braided nylon suture. 
   9. If the medullary canal remains open, the elevated periosteum can be reapproximated at this point with heavy absorbable suture.
   10. The posterior tissue then gets divided with an amputation knife or cautery. 
   11. The sciatic/tibial nerve is now divided and allowed to retract as above
   12. The tourniquet is released, and all bleeding ligated.
   13. A subfascial drain is left in place if needed but generally unnecessary. 
   14. The anterior and posterior flap is reapproximated with a heavy absorbable suture at the fascia.
   15. Skin and subcutaneous tissues closed in layers. 
2. Through-knee amputation
   1. An elliptical incision similar to the above-knee is made with the apices at the medial and lateral epicondyles near the top of the patella if a line were extended around the femur.  The anterior flap distal margin extends to the tibial tuberosity.  The posterior flap should attempt to mirror the anterior flap. 
   2. A tourniquet is used as above.  The surgeon employs a similar technique through the fascia as above. 
   3. The patellar tendon is detached from the tibia, and the surgeon enters the knee joint. 
   4. The joint capsule is incised circumferentially and the cruciate ligaments divided from within the knee joint.
   5. Before dividing the posterior joint capsule and posterior tissues, it is useful to identify the semitendinosus medially and the biceps femoris laterally as the insert into the tibia posteriorly.  They should be held with a Kocher clamp to prevent retraction.
   6. Popliteal artery and vein individually suture ligated.
   7. The common peroneal and tibial nerves are divided under tension and transected sharply to allow for retraction. 
   8. The posterior tissues get divided with amputation knife or cautery. It is not necessary to preserve any gastrocnemius muscle.  
   9. The specimen is removed at this point.
   10. An oscillating saw is used to make six osteotomies removing all of the articular surfaces while preserving the majority of the adductor insertion medially; this will be cancellous bone with no medullary canal.
   11. The patella is then everted and removed from the inner surface of the patellar tendon taking care not to injury the thin skin from the bare area in the mid-tendon.
   12. The tourniquet is released and further hemostasis achieved with ligatures.
   13. Myodesis then follows by suturing the semitendinosus and biceps to the cruciate remnant posteriorly and the patellar tendon to the cruciate anteriorly. This process is performed with heavy fiber-wire or braided nylon. 
   14. Fascia, subcutaneous tissue, and the skin closed as above. 
3. Open below-knee amputation
   1. This procedure is performed as distal as the soft tissues allow and can take place expeditiously with a Gigli saw through all structures followed by suture ligation of vascular structures. The residual limb is covered with wet to dry dressings once hemostasis obtained. 
   2. The alternative is to use a scalpel and electrocautery for the skin, subcutaneous tissue, and muscle followed by isolation and control of vascular bundles. A power saw or the same Gigli saw can be used for bone. The residual limb is covered with wet to dry dressings upon achieving hemostasis. 
4. Formal below-knee amputation
   1. The level selected depends largely on soft tissue viability with the ideal length being approximately 12 to 18 cm from the tibial tubercle.[17]
   2. It is useful to have a standard technique to determine skin flaps.  This author prefers to measure the diameter at the transection site and make the anterior flap one-half the circumference and the posterior long flap's full circumference; this prevents unnecessary tension at the time of closure. Additionally, longer residual limb lengths typically involve a smaller circumference and thereby have less chance for tension. 
   3. The incisions are carried through the skin, subcutaneous tissue, and anterior muscle with suture ligation of vasculature identified.
   4. The tibial bone gets transected with a power saw, or Gigli saw and tibial edges blunted with use of a rasper. The power saw or rasper can be used to bevel the anterior aspect of the tibia. This process allows for less trauma to the posterior flap as it sits along a smooth surface. 
   5. The fibula gets transected in the same manner at approximately 1 cm proximal to the tibial transection and sharp edges removed with rasper, giving the residual limb a cornified aspect. 
   6. The posterior tissue is divided with amputation knife leaving only a thinned portion of the soleus but preserving the gastrocnemius. 
   7. At this point ligation of anterior tibial, posterior tibial, and peroneal arteries are confirmed before the tourniquet is released.  The tibial, deep and superficial peroneal, and soleus nerves divide on tension.
   8. The myodesis is performed by bringing the Achilles tendon to the tibia. Three osteotomies are created with a 2 mm drill bit in the anterior portion of the tibia.  Fiber-wire or heavy braided nylon is used to secure the Achilles to the tibia utilizing the three osteotomies in a mattress fashion.  
   9. Skin and subcutaneous tissues closed in layers. 
5. ERTL amputation
   1. All steps similar to formal below-knee amputation except a keyhole incision is used extending just lateral to the tibial distally and then around the ankle. The tibialis anterior muscle is preserved in the anterior compartment.
   2. An osteal periosteal graft is raised using a hammer and chisel and left attached to the tibia anteriorly.  
   3. The fibula is transected at the same length as the tibia.
   4. Soleus muscle and anterolateral compartment muscle are transected. A GIA stapler is useful for this.
   5. Vascular bundles and nerves receive similar treatment.
   6. A portion of the fibula is trimmed to create a strut between the tibia and fibula, which gets secured with a tightrope device, plate, or headless screw.
   7. The periosteal graft is secure around the fibula strut to aid in ossification
   8. Tibialis anterior is secured over the strut followed by the Achilles myodesis (pants over vest).
   9. The closure begins anteriorly, and the skin and subcutaneous tissue resected as the closure proceeds posteriorly 
6. Syme amputation
   1. A weight-bearing amputation through the ankle that involves removal of all of the bones of the foot while preserving the heel pad for weight-bearing
7. Boyd  amputation
   1. A weight-bearing amputation through the ankle that preserves the calcaneus and heel pad for weight-bearing.
   2. The calcaneus gets fused to the tibia and is non-mobile
8. Chopart amputation
   1. A weight-bearing amputation at the midtarsal level preserving the additional length of the foot

Lower extremity amputations involve significant perioperative morbidity and mortality. Thirty-day postoperative mortality rates can range from 4% to 22%.[18] Long term mortality rates at 1, 3, and 5 years can reach 15, 38, and 68%, respectively.[19] Mortality rates in diabetic lower extremity amputation patients can be as high as 77% at 5 years.[20] Risk factors for death in the perioperative setting include AKA, postoperative cardiac complications, age over 74 years, and acute renal failure.[21] A review of 2879 amputees demonstrated the most common post-surgical complications included pneumonia (22%), acute kidney injury (15%), deep venous thrombosis (15%), acute lung injury/acute respiratory distress syndrome (13%), osteomyelitis  (3%) and flap failure (6%).[22]

Wound complications, which include dehiscence, seroma, hematoma, can occur in 12% to 34% of BKA patients and 6% to 16% of AKA patients.[23] Risk factors for wound complications include sepsis, compartment syndrome, end-stage renal disease, ongoing tobacco use, body mass index over 30 kg/m2, and BKA.[24] A retrospective study showed that the use of incisional negative pressure wound therapy (NPWT) in major limb amputation and revision amputation had demonstrable benefit in decreasing the risk of wound complications.[25]

Phantom limb pain (PLP) is the pain that persists after complete tissue healing and is characterized by dysesthesia at the level of the absent limb. Patients describe this pain as burning, throbbing, stabbing, sharp as well as the sensation that the amputated limb is in an abnormal position.[26] This pain can be present in 67% of patients at six months and 50% of patients at five to seven years.[27][28] There are several risk factors for developing PLP, which include: the presence of pre-amputation pain, female gender, upper extremity amputations, and bilateral amputations of the upper and/or lower extremities.[26] A multidisciplinary approach which includes surgical technique, regional analgesia, pharmacological agents, physical therapy and psychotherapy are all key components in the peri-operative care of an amputee that can have a strong impact in decreasing the risk of PLP. 

Revision amputation procedures can occur in as many as 42% of patients who underwent a below-knee amputation secondary to trauma. Additionally, up to 13% of patients undergo revision to a higher level of amputation. Age, presence of a crush injury, compartment syndrome, and experiencing a major post-surgical complication were significant risk factors of revision amputation.[22]

It is also important to include psychological trauma as a complication of limb loss. A recent review performed by Mckechnie et al. reveals that depression can occur in 20.6 to 63% of patients (3 times higher than the general population) and anxiety in 25% to 57% (approximately the same as the general population) with 83% of patients attending a psychiatric clinic at one point after their surgery.[29] Darnall et al. demonstrated an increased risk of depressive symptoms in patients undergoing an amputation secondary to trauma versus vascular disease or cancer.[30] Current research, such as "Amputees Unanimous: A 12-step program", is focusing on a multimodal approach toward the care of an amputee which aims to provide encouragement, support, and optimism for the future.[31] Further research is needed to determine their impact on this patient population. 

An amputation not only reduces mobility but can cause significant impairment in quality of life. There is increased energy expenditure with higher levels of amputation.[32] The mean oxygen consumption in unilateral below-knee amputees compared to unimpaired subjects has been shown to increase by 9%. This increase is even more notable in above-knee amputees at approximately 49% and 280% in those with bilateral above-knee amputees.[33] The rate of metabolic expenditure is higher in dysvascular amputees compared to traumatic amputees[34] The extent of disease will dictate the level of the amputation. Through-knee amputation is a reasonable alternative to above-knee amputation should perfusion, and soft tissue conditions allow. TKA has demonstrated similar morbidity and mortality when compared with AKA and can provide a better end-weight-bearing residual limb, improved stability with adductor preservation, improved prosthetic comfort.[35] An above-knee prosthetic can sit on the ischium and can require removal for activities of daily life such as sitting on the toilet. The through-knee amputation is generally preferable in younger patients or any patients with ambulatory potential with the above-knee amputations preserved for those non-ambulatory bed-bound patients or those with advanced vascular disease. 

Technological advancements in materials and ways to optimize the coupling between the residual limb and socket drive prosthetic development. Gel liners are used to protect the skin while allowing for the suction suspension of the prosthetic. An active suction device can also be implemented in the form of a mechanical pump that activates during ambulation. Improper fit leading to discomfort is the most common reason for rejection of prosthetic devices. However, patients may also be very self-conscious of the appearance of their residual limb, which may disincentivize its use. Therefore, a silicone cover or sleeve which mirrors the contralateral limb (including tattoos and hair) can be applied.[36] A prosthetist must be involved early in the post-operative care to assist with stump sock fitting and evaluation for an eventual prosthetic limb that adjusts to the patients' needs.

an interprofessional approach is necessary for the care of an amputee. Performing an amputation is a stressful period for most patients. If the procedure is elective, a mental health nurse should consult with the patient. Also, a prosthetic professional should consult with the patient to explain the different prosthetics and when the patient will get fitted with the appliance. After surgery, a wound care nurse must follow the patient to ensure that there is complete healing before fitting any prosthetic device. Other nursing actions and duties are detailed further in the following sections. Pharmacists will provide support for glycemic control in patients with diabetes, pain control, and overall medication reconciliation, reporting any issues to the rest of the interprofessional team.

Providers caring for this patient population should include social workers, nursing staff, pharmacists, physical therapists, occupational therapists, prosthetists, psychologists, and multispecialty physicians all working in close coordination to provide the best outcome. Every clinician is responsible for ensuring that the patient still can function in society. The social worker must ensure that the home is suitable and that the patient has adequate resources and support services.

Care of an amputee should be individualized based on the patients' overall health status. Clear communication with the patient and their families regarding their treatment course and expectations must be established in the pre-operative setting to facilitate post-operative care and improve the patient-physician relationship.

Only through a thorough interprofessional team effort, involving physicians, surgeons, mental health professional, physical and occupational therapists, specialized nursing, and pharmacists, extending across many months, can patients receiving a lower extremity amputation achieve optimal results and maintain an adequate quality of life. [Level V]

The care of an amputee begins and ends with nursing actions and interventions. Whether it involves an emergency medicine admission or a clinic visit, the nursing staff is usually the first point of contact for a patient. Diabetic or peripheral vascular disease patients with foot or leg wounds can often be undergoing wound care with the assistance of a home-health nurse. Should there be a lack of progression in wound healing or early signs of infection, they are the first to refer the patient to a medical provider and in some instances, the emergency department. After that, an ER or hospital nurse is generally the first to greet a patient and obtain vital signs which can indicate the severity of disease and will, therefore, dictate the hospital setting in which this patient receives their care. With the assistance of nursing staff, the wound is exposed, and the patient is assessed from head-to-toe looking for pressure ulcers, ecchymosis, or hematomas in patients who are wheelchair or bed-bound. Nursing actions also include obtaining adequate intravenous access, medication dispensing and administration, serial symptom assessment including pain, monitoring vital signs, providing wound care and patient hygiene, as well as being a liaison between the patient, their families, and medical providers. 

The care of an amputee involves an interprofessional approach in which nursing staff plays a key role. Monitoring in the post-operative setting includes obtaining and recording vital signs, pain scores, and laboratory values. Serial wound assessments allow for early detection of post-operative bleeding and will also allow the nurse to perform temporizing maneuvers (digital pressure, dressing reinforcement) while a medical provider is alerted. Pain scores are diligently obtained to titrate the patients' pain medication accordingly and provide the best condition for early mobilization. Close communication between the medical providers and nursing staff is necessary to provide the patient with individualized care based on their needs.