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Acs0620 Lower Extremity Amputation For Ischemia


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  • 1. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 1 20 LOW ER-EXTR EMITY AM PUTATION FOR ISCHEMI A William C. Pevec, MD, FACS Patients with infected, painful, or necrotic lower extremities definitive amputation. This can be accomplished with local can be restored to a better functional level by means of a soft tissue débridement, single-toe open amputation, or properly selected and performed amputation. This procedure guillotine amputation across the ankle. should be considered reconstructive and restorative. In what Careful preoperative medical assessment is essential. follows, I address amputations across the toe, the forefoot, Lower-extremity amputation for ischemia is associated with the leg, and the thigh. Because Symes amputations and hip a mortality of 4.5 to 18%,1–9 owing to the poor overall con- disarticulations are seldom appropriate on ischemic limbs, dition of the patient population. Accordingly, optimization of I omit discussion of these procedures. cardiac and pulmonary function and control of systemic infection are mandatory. Finally, the timing of elective amputation is crucial. Because General Operative Planning the loss of a limb is a difficult and frightening thing for Selecting the appropriate level of amputation is of primary a patient to accept, there is a natural tendency to delay ampu- importance for healing and preservation of function. For an tation for as long as possible. This tendency is understand- ambulatory patient who has either a palpable pulse over the able but must be weighed against the potential problems dorsal pedal or posterior tibial artery or a functioning infrain- associated with delay, such as poor preoperative pain control, guinal arterial bypass graft, amputation on the foot (either toe which leads to an increased incidence of postamputation amputation or transmetatarsal amputation) is appropriate. phantom limb pain, and extended preoperative immobility, For an ambulatory patient who has a palpable femoral pulse which leads to physical deconditioning and makes prosthetic and a patent deep femoral (profunda femoris) artery, whose limb rehabilitation more difficult. A preoperative consultation skin is warm at least to the level of the ankle, and who has no with a physiatrist can allay some of the patient’s anxiety by skin lesions on the proposed amputation flaps, amputation addressing the expected postoperative course of rehabilitation below the knee is appropriate. For a nonambulatory patient and thereby removing some of the fear of the unknown. who has ischemic rest pain, ulceration, or gangrene, amputa- tion above the knee is appropriate. Arterial reconstruction is not indicated if the extremity is nonfunctional. Below- Toe Amputation the-knee amputation does not offer nonambulatory patients Amputation of the toe can be done either across a phalanx any functional advantage; moreover, it is less likely to heal or across a metatarsal bone; the latter procedure is commonly and often results in a flexion contracture at the knee that referred to as a ray amputation. Many of the perioperative leads to pressure ulceration of the stump. Above-the-knee issues are essentially similar for the two approaches; however, amputation depends on pulsatile flow into the ipsilateral indications and operative details differ somewhat and thus internal iliac artery for successful healing. Above-the-knee will be described separately. amputation is also necessary for a patient whose skin is cool at or above the midcalf or who has skin lesions at or proximal   to the midcalf. As noted (see above), for a toe amputation to heal pro- Several adjunctive measurements (e.g., transcutaneous perly, there must be either a palpable pulse over the dorsal oxygen tension and segmental arterial pressure) have been pedal or posterior tibial artery or a functioning bypass graft used to select the level of amputation but have not proved to an infrapopliteal artery. If tissue necrosis or infection is particularly helpful. Generally, these adjuncts can reliably confined to the distal or middle phalanx, transphalangeal determine a level of amputation at which healing is virtually amputation is appropriate; if tissue loss or necrosis involves ensured, but they cannot reliably determine the level at the proximal phalanx, ray amputation is indicated. If tissue which an amputation will not heal. Consequently, reliance necrosis or infection extends over the metatarsophalangeal on such measures to select the level of amputation will joint, either transmetatarsal amputation of the entire forefoot result in an unnecessarily high percentage of more proximal or below-the-knee amputation is usually necessary (see amputations. below). In most cases, definitive amputation can be accomplished Multiple transphalangeal amputations are functionally well in a single stage. Local cellulitis can usually be controlled tolerated. If, however, ray amputation of the great toe or of beforehand with bed rest and systemic administration of more than one smaller toe is called for, it may be preferable antibiotics. Undrained pus or recalcitrant cellulitis, however, to perform a transmetatarsal amputation of the forefoot. must be treated with débridement and drainage in advance of Adequate skin coverage may be difficult to achieve with a DOI 10.2310/7800.2008.S06C20 05/08
  • 2. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 2 great-toe or multiple-toe ray amputation. In addition, ray taken not to create excessively long flaps, which may lack amputation of more than one of the middle toes often causes sufficient perfusion for healing, or to create undermined central deviation of the remaining outside toes, which can bevels with the scalpel [see Figure 2], which will lead to lead to ulcerations secondary to abnormal pressure points. epidermolysis of the suture line. Finally, loss of the first metatarsal head or of several of the The incision is extended down to the phalanx, and the soft other metatarsal heads results in abnormal weight bearing on tissues are gently separated from the bone with a small peri- the remaining metatarsal heads, which may give rise to late osteal elevator. All tendons and tendon sheaths are débrided ulceration. because the poor vascularity of these tissues may compromise the healing of the toe. The phalanx is transected at the level   of the apices of the skin incisions [see Figure 1]. Care must be taken not to leave the remaining bone segment too long: this Transphalangeal Amputation places undue tension on the skin flaps and is a primary cause Digital block anesthesia is ideal for transphalangeal ampu- of poor healing. The best way of transecting the phalanx is to tation. A 25-gauge needle is inserted into the skin over the use a pneumatic oscillating saw. Manual bone cutters can medial aspect of the dorsum of the proximal phalanx and splinter the bone, and manual saws can cause extensive advanced until the bone is encountered. The needle is then damage to the soft tissues. The bone is always transected withdrawn slightly, and a small amount of fluid is aspirated across the shaft; because of the poor vascularity of the articu- to confirm that the tip of the needle is not in a blood vessel. lar cartilage, disarticulation across a joint typically leads to Next, 0.5 to 1.0 ml of lidocaine, 0.5% or 1.0% without poor healing. epinephrine, is slowly injected. The needle is then carefully Hemostasis is achieved with absorbable sutures and limited advanced medial to the bone until the tip can be felt pressing use of the electrocautery. Excessive tissue manipulation and against (but not puncturing) the plantar skin. Again, the electrocauterization should be avoided. The skin edges are needle is withdrawn slightly, fluid is aspirated, and 0.5 to carefully approximated with simple interrupted nonabsorb- 1.0 ml of lidocaine is injected. The same technique is repeated able monofilament sutures; perfect apposition is necessary to on the lateral aspect of the proximal phalanx. In this way, all maximize the potential for primary healing. The sutures must four digital nerve branches are blocked. If multiple toe ampu- not be placed too close to the skin edges, because the heavily tations are required, an ankle block, epidural anesthesia, keratinized skin of the foot is easily lacerated. The final step spinal anesthesia, or general anesthesia may be used. is the application of a soft dressing. An incision is made to create dorsal and plantar skin flaps. Typically, these flaps are equal in length; however, depending Ray Amputation on the location of the skin lesion, either the dorsal flap or the For ray amputation [see Figure 3], spinal, epidural, or plantar flap can be left longer [see Figure 1]. Care must be general anesthesia may be employed. A so-called tennis- racket incision is made—that is, a straight incision along the dorsal surface of the affected metatarsal bone coupled with a circumferential incision around the base of the toe. The goal is to save all available viable skin on the toe; this skin is used to ensure a tension-free closure, and any excess skin can be débrided later, at the time of closure. Again, undermined bevels are avoided. The incision is taken down to the bone, and the soft tissues are separated from the distal metatarsal bone with a periosteal elevator. Dissection must be kept close to the affected metatarsal head to prevent injury to the adja- cent metatarsophalangeal joint, which can lead to necrosis of a the adjacent toe. The metatarsal bone is transected across the shaft with a pneumatic oscillating saw. The tendons and the tendon sheaths are débrided. Meticulous hemostasis is achieved with absorbable sutures and limited use of the electrocautery. The skin is approxi- mated with simple interrupted nonabsorbable monofilament sutures [see Figure 4]. If sufficient viable skin was preserved, a flap of plantar skin is rotated dorsally, and the incision is closed in the shape of a Y. Alternatively, the medial and lateral edges are shifted (one proximally and the other dis- b tally), the corners are trimmed, and the incision is closed in a linear fashion. A soft supportive dressing is applied. Figure 1 Toe amputation: transphalangeal amputation. Transphalangeal amputation can be performed either with  dorsal and plantar flaps of equal length (a) or with a plantar flap that is longer than the dorsal flap (b). The phalanx is Complications of toe amputation include bleeding, infec- transected at the level of the apex of the skin flaps (dashed tion, and failure to heal. Because even a small amount of line). The bone is transected through the shaft of the phalanx, bleeding under the skin flaps can prevent proper healing, never across the joint. meticulous hemostasis is mandatory. In most cases, infection 05/08
  • 3. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 3 a b Figure 2 In a lower-extremity amputation, the skin is always incised perpendicular to its surface (a). Given the varying contours encountered during extremity amputation, it can be difficult to maintain the perpendicular orientation of the scalpel; however, an incision that undermines the proximal skin flap (b) will devascularize the epidermis and lead to necrosis of the suture line. and failure to heal are attributable to poor patient selection them to function without stepping on the foot that was oper- and poor surgical technique; the usual result is a more ated on. Hospital discharge is delayed until such techniques proximal amputation. are mastered.  Transmetatarsal Amputation For optimal healing, there must be an extended period (2 to 3 weeks) during which no weight is borne by the foot that   underwent toe amputation. Once healing is complete, the patient should be able to walk normally, with no need for As noted (see above), transmetatarsal amputation is indi- orthotic or assist devices. Beginning ambulation too early can cated if there is tissue loss in the forefoot involving the first disrupt healing flaps and necessitate more proximal amputa- metatarsal head, two or more of the other metatarsal heads, tion, which lengthens the hospital stay and increases long- or the dorsal forefoot. It is contraindicated if there is exten- term disability. For these reasons, toe amputation in patients sive skin loss on the plantar surface of the foot or on the with arterial occlusive disease is not an outpatient procedure. dorsum proximal to the midshaft of the metatarsal bones. Patients are kept on bed rest and instructed in techniques The peroneus longus and the peroneus brevis insert on the (e.g., use of a wheelchair, a walker, or crutches) that allow proximal portions of the fourth and fifth metatarsal bones; if a b Figure 3 Toe amputation: ray amputation. (a) A longitudinal incision is made along the dorsum of the shaft of the metatarsal bone of the affected toe. A circumferential incision is then made around the phalanx. The circumferential incision should be placed as distal on the toe as there is viable skin so that as much skin as possible is retained for closure of the wound. (b) The metatarsal bone is transected across its shaft, proximal to the metatarsal head; the joint is never disarticulated. 05/08
  • 4. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 4 a b Figure 4 Toe amputation: ray amputation. (a) If adequate skin is available, a plantar flap can be rotated dorsally and the skin closed in a Y configuration. This closure is technically easy to perform; however, there is a risk of skin necrosis at corners A and B. (b) Alternatively, the skin can be closed in a linear fashion. Corners A and B are gently trimmed. Corner B is shifted distally toward point D as corner A is shifted proximally. A slight dog-ear will result at point E; however, it will diminish with time. these insertions are sacrificed, inversion of the foot results,   eventually leading to chronic skin breakdown from the side of Spinal, epidural, or general anesthesia may be employed the foot repeatedly striking the ground during ambulation. for transmetatarsal amputation. Placement of a tourniquet on Transmetatarsal amputation is also contraindicated if there is the calf is a useful adjunctive measure. This step greatly a preexisting footdrop (peroneal palsy). reduces intraoperative blood loss. More important, the blood- 05/08
  • 5. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 5 less operative field that results allows more accurate assess- with the scalpel, and the soft tissue is dissected away from the ment of tissue viability and hence more precise selection of first metatarsal bone with a periosteal elevator to a point the level of amputation; in a field stained with extravasated about 1 cm proximal to the dorsal skin incision. The first blood, it is easy to leave behind nonviable tissue that will metatarsal bone is then transected perpendicular to its doom the amputation. Use of a tourniquet is, however, con- shaft at the level of the dorsal skin incision with a pneumatic traindicated in patients who have a functioning infrapopliteal oscillating saw. This process is repeated for each individual artery bypass graft. metatarsal bone, with care taken to follow the normal contour After sterile preparation and draping, the leg is elevated to of the forefoot by cutting the lateral metatarsal bones at a help drain the venous blood, and a sterile pneumatic tourni- level slightly proximal to the level at which the more medial quet is placed around the calf, with care taken to pad the skin bones are transected. All visible digital arteries are clamped under the tourniquet and to position the tourniquet over the and tied with absorbable ligatures. If a tourniquet was used, calf muscles, where it will not apply pressure over the fibular it is deflated at this time. All tendons and tendon sheaths are head (and the common peroneal nerve) or other osseous débrided from the wound. prominences. The tourniquet is then inflated to a pressure Meticulous hemostasis is achieved with absorbable sutures higher than the systolic blood pressure. In patients who do and limited use of the electrocautery. Any sharp edges on the not have diabetes mellitus, a tourniquet inflation pressure metatarsal bones are smoothed with a rongeur or a rasp. The of 250 mm Hg is typically employed; in patients who have wound is irrigated to flush out devitalized tissue and throm- diabetes mellitus and calcified arteries, a pressure of 350 to bus. The plantar flap is trimmed as needed. The dermis is 400 mm Hg is preferred. approximated with simple interrupted absorbable sutures, An incision is made across the dorsum of the foot at the and the knots are buried. Because the edge of the plantar flap level of the middle of the shafts of the metatarsal bones, is generally longer than the edge of the dorsal flap, the sutures extending medially and laterally to the level of the center of must be placed slightly farther apart on the plantar flap than the first and fifth metatarsal bones, respectively [see Figure 5]. on the dorsal flap if perfect alignment is to be obtained. It is The dorsal incision is curved proximally at the medial and imperative to achieve the correct skin alignment with the lateral edges to ensure that no dog-ears remain at the time of dermal suture layer. Once this is accomplished, the skin edges closure. The dorsal incision is continued perpendicularly are gently and perfectly apposed with interrupted vertical through the soft tissues on the dorsum down to the metatar- mattress sutures of nonabsorbable monofilament material. sal bones. The plantar incision is extended distally to a point Finally, a soft supportive dressing with good padding of the just proximal to the toe crease. Care is taken not to bevel the heel is applied; casts and splints are avoided because of the skin incisions. risk of ulceration of the heel or over the malleoli. A plantar flap is created by making an incision with the scalpel adjacent to the metatarsophalangeal joints; the inci-  sion is then carried more deeply to the level of the midshafts If a tourniquet is not used, intraoperative blood loss can be of the metatarsal bones on their plantar surfaces. The perios- substantial; the blood pools in the sponges and drapes, often teum of the first metatarsal bone is scored circumferentially out of the anesthesiologist’s field of view. Consequently, good Figure 5 Transmetatarsal amputation. The skin incisions are shown from various angles. The metatarsal shafts are divided in their midportions (dashed line). The metatarsal bone transection is at the level of the apices of the skin incision, and the lateral metatarsal bones are cut slightly more proximally than the medial metatarsal bones, in a pattern reflecting the normal contour of the forefoot. 05/08
  • 6. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 6 communication between the surgeon and the anesthesiologist the skin and soft tissues to the bone. If the arteries are patent, is crucial for preventing ischemic complications secondary to the assistant applies circumferential pressure to the distal hemorrhage. calf. The distal tibia and fibula are then divided with a Postoperative complications include bleeding, infection, Gigli saw. Hemostasis is achieved with suture ligation and and failure to heal, all of which are likely to result in more electrocauterization. A moist dressing is applied. proximal amputation. They can best be prevented by means of careful patient selection and meticulous surgical  technique. After the procedure, the patient is kept on bed rest and  given systemic antibiotics. Formal below-the-knee amputa- tion can be performed when the cellulitis resolves, usually For proper healing, postoperative edema must be avoided within 3 to 5 days. Routine dressing changes are unneces- and the plantar flap protected against shear forces. To pre- sary—first, because they are painful, and second, because the vent swelling, the patient is kept on bed rest with the foot elevated for the first 3 to 5 days. This step is particularly decision to proceed with formal below-the-knee amputation important if the transmetatarsal amputation was performed is based on the extent of the cellulitis in the calf, not on the simultaneously with arterial reconstruction, which carries a appearance of the transected ankle. high risk of reperfusion edema of the foot. After 3 to 5 days, the patient is instructed in techniques for moving in and out Below-the-Knee Amputation of the wheelchair without stepping on the foot. The foot that was operated on should not bear any weight at all for at least   3 weeks; early weight bearing may disrupt the healing of the plantar flap and necessitate more proximal amputation. Below-the-knee amputation is indicated when the lower Once healed, patients should be able to walk independently extremity is functional but the foot cannot be salvaged by with standard shoes. There is, however, a risk that they may arterial reconstruction or by amputation of one or more of the trip over the unsupported toe of the shoe. In addition, toes or the forefoot. Healing can be expected if there is a the pushoff normally provided by the toes is lost after trans- palpable femoral pulse with at least a patent deep femoral metatarsal amputation, and this change results in a halting, artery, provided that the skin is warm and free of lesions at flat-footed gait. These problems can be obviated by using an the distal calf. Before formal below-the-knee amputation, orthotic shoe with a steel shank (to keep the toe of the shoe infection should be controlled with antibiotic therapy, from bending and causing tripping) and a rocker bottom (to débridement, and, if indicated, guillotine amputation. It is provide a smooth heel-to-toe motion). advisable to obtain consent to possible above-the-knee ampu- tation beforehand in case unexpected muscle necrosis is Guillotine Ankle Amputation encountered below the knee. As with any amputation, the surgeon’s preoperative   interaction with the patient should be as positive as possible. Guillotine amputation across the ankle is indicated when a patient presents with extensive wet gangrene that precludes salvage of a functional foot (e.g., wet gangrene that destroys the heel, the plantar skin of the forefoot, or the dorsal skin of the proximal foot). In such patients, initial guillotine amputa- tion through the ankle is safer than extensive débridement: the operation is shorter, less blood is lost, the risk of bactere- mia is reduced, and better control of infection is possible. Guillotine amputation is also indicated in patients with foot infections who have cellulitis extending into the leg. Transec- tion at the ankle, perpendicular to the muscle compartments, tendon sheaths, and lymphatic vessels, allows effective drain- age and usually brings about rapid resolution of the cellulitis of the leg, thus permitting salvage of the knee in many cases in which the knee might otherwise be unsalvageable.   General anesthesia is preferred for guillotine ankle amputa- tion; regional anesthesia is relatively contraindicated for critically ill patients who are in a septic state. Anesthesia is required for no more than 15 to 20 minutes. A circumferential incision is made at the narrowest part of the ankle (i.e., at the proximal malleoli) regardless of the level of the cellulitis [see Figure 6]. This placement takes the line of Figure 6 Guillotine ankle amputation. The skin incision is incision across the tendons, thereby preventing bleeding from made circumferentially at the narrowest portion of the ankle. transected muscle bellies. The incision is then carried through The bones are then transected at the same level (dashed line). 05/08
  • 7. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 7 A constructive perspective to convey is that the amputation, though regrettably necessary, is in fact the first step toward rehabilitation. A well-motivated patient whose cardiopulmo- nary status is not too greatly compromised can generally be expected to walk again, albeit at an increased energy cost. In this regard, a preoperative discussion with a physiatrist can be very helpful, as can a meeting with an amputee who is doing well with a prosthesis. By inculcating a positive attitude in the patient before the procedure, the surgeon can greatly improve the patient’s chances of achieving full rehabilitation, as well as decrease the time needed for rehabilitation.   Epidural, spinal, or general anesthesia is appropriate for below-the-knee amputation. The lines of incision should be marked on the skin. The primary level of amputation is deter- mined by measuring a distance of 10 cm from the tibial tuberosity [see Figure 7]. The circumference of the leg at this level is then measured by passing a heavy ligature around the leg and cutting the ligature to a length equal to the circumfer- ence. The ligature is folded into thirds and cut once more at one of the folds, so that two segments of unequal length remain. The longer segment of the ligature, which is equal in length to two-thirds of the leg’s circumference 10 cm below the tibial tuberosity, is used to measure the anterior trans- verse incision; this incision is centered not on the tibial crest but on the gastrocnemius-soleus muscle complex. The shorter segment, which is one-third of the leg’s circumference at this level, is used to measure the posterior flap; the line of the posterior incision runs parallel with the gastrocnemius-soleus complex. To prevent dog-ears, the medial and lateral ends of the anterior transverse incision are curved cephalad before meeting the posterior incision, and the distal corners of the posterior incision are curved as well. Blood loss can be reduced by using a sterile pneumatic tourniquet. A gauze roll is passed around the distal thigh. The leg is elevated to drain the venous blood, and the tour- niquet is applied over the gauze roll. The tourniquet is inflated to a pressure of 250 mm Hg (350 to 400 mm Hg if the patient has heavily calcified arteries). The assistant elevates the leg, and the incision on the posterior flap is made first, followed by the anterior transverse incision; this sequence helps prevent blood from obscuring the field while the incisions are being made. The incisions are carried fully through the dermis, and the skin edges are allowed to separate and expose the subcutaneous fat. Care is taken to keep the scalpel per- pendicular to the skin so as not to bevel the incision, which can lead to necrosis of the epidermal edges [see Figure 2]. The anterior muscles are transected with the scalpel in a direction parallel to the transverse skin incision. The tibia is scored circumferentially, and a periosteal elevator is used to dissect the soft tissues away from the tibia for a distance of approximately 3 to 4 cm. The tibia is then transected just Figure 7 Below-the-knee amputation. The transverse proximal to the transverse skin incision. Dividing the tibia incision (A) is made 10 cm distal to the tibial tuberosity. Its more than 1 cm proximal to the anterior skin incision will length is equal to two thirds of the circumference of the leg at that level. The posterior incision (B) is made parallel with the cause the thin skin of the anterior leg to be pulled taut over gastrocnemius-soleus muscle complex. The length of the the cut end of the tibia by the weight of the posterior flap, posterior flap is equal to one third of the measured circum- thereby leading to skin ulceration. The tibia is transected ference of the leg. The corners of the incisions are curved to perpendicularly, with a cephalad bevel of the anterior 1 cm avoid dog-ears. 05/08
  • 8. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 8 to keep from creating a sharp point at the tibial crest [see to the tibial transection level. The distal end of the tibia is Figure 8]. The tibia can be transected with either a Gigli saw lifted with a bone hook, and division of the posterior muscles or an oscillating saw; because of the unpleasant sound of the is completed with an amputation knife. The specimen is then power saw, the Gigli saw is preferred if the patient is under handed off the field. regional anesthesia. Sedation should be augmented in awake The anterior tibial, posterior tibial, and peroneal arteries patients before division of the tibia. Benzodiazepines provide and veins are clamped, and the tourniquet is released. Clamps good sedation and amnesia. are placed on all other bleeding vessels. The posterior tibial The lateral muscles are divided, and the fibula is scored and sural nerves are placed on gentle traction and clamped circumferentially. A periosteal elevator is used to dissect the proximally. The nerves are transected and ligated, and the soft tissues away from the fibula to a point 2 to 3 cm cepha- proximal nerves are allowed to retract into the soft tissues so lad to the level at which the tibia was transected. The fibula as to prevent painful neuromas at the end of the stump. All is then transected with a bone cutter at least 1 cm cephalad clamped structures are then ligated with absorbable ligatures. The nerves are ligated because their nutrient vessels can bleed significantly. The distal anterior tip of the tibia is smoothed with a rasp to decrease the risk of skin ulceration over this osseous prominence. The stump is gently irrigated to remove all thrombus and devitalized tissue and to reveal any bleeding sites that may have been missed. Electrocauterization is rarely necessary. The deep muscle fascia—not the Achilles tendon—is approximated with simple interrupted absorbable sutures, with care taken to align the posterior flap with the anterior incision. The skin is approximated by placing simple inter- rupted absorbable sutures, with buried knots, at the dermal- epidermal junction (interrupted subcuticular sutures). A carefully padded posterior splint is applied to prevent flexion contracture.  The most common complications after below-the-knee amputation are bleeding, infection, and failure to heal, all of which are likely to result in a more proximal amputation, frequently accompanied by loss of the knee. Prevention of these complications depends on careful patient selection, preoperative control of infection, and meticulous surgical technique. To walk with a prosthetic leg, the patient must be capable of fully extending and locking the knee; thus, flexion contrac- ture at the knee is a major complication. Such contractures are usually attributable either to poor pain control or to non- compliance with knee extension exercises. Good periopera- tive analgesia is of vital importance because knee flexion is the position of comfort and the patient will be unwilling to extend the knee if doing so proves too painful. To maintain knee extension, the patient should be placed in a splint in the early postoperative period. Once postoperative pain has abated, the splint can be removed. At this point, the patient must be taught extension exercises, in which the quadriceps muscles are contracted to maintain the length of the hamstring muscles. If a patient spends all of his or her time in a sitting position with the knee flexed, a flexion contracture will quickly develop. Once this happens, the patient may find it very difficult to regain full knee extension, and without full knee extension, prosthetic limb rehabilitation is impossible. Phantom sensation is a common complication after below- Figure 8 Below-the-knee amputation. In this lateral view of the-knee amputation but is rarely of any consequence. the right leg, the tibia is beveled anteriorly, and the anterior Phantom pain, on the other hand, can be devastating. Some- portion is smoothed with a rasp. The fibula is transected at times, phantom pain develops as a consequence of uninten- least 1 cm proximal to the level of transection of the tibia. tional suggestions made to the patient by medical personnel 05/08
  • 9. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 9 who fail to distinguish between the two entities. For example, The presence of pulsatile flow into a well-developed ipsila- a patient remarks to a medical attendant that he or she can teral internal iliac artery usually ensures healing, but even still feel the amputated foot and toes, and the attendant when there is more severe arterial occlusive disease in the suggests in response that the patient has phantom pain; the pelvis, healing can sometimes be achieved. Above-the-knee patient then focuses on the sensation and exaggerates the amputation is also indicated if there is tissue necrosis or severity of the foot and toe discomfort, setting up a cycle of uncontrollable infection extending cephalad to the midleg. ever-worsening pain. This scenario is even more likely if the Above-the-knee amputation is the procedure of choice in the patient had prolonged ischemic rest pain before the amputa- case of gangrene or ulceration of a completely nonfunctional tion. Phantom pain can be prevented by (1) encouraging lower extremity. early amputation in a patient with a hopelessly ischemic foot (while taking into account the patient’s need to come to grips   with the prospect of amputation), (2) providing good pain Epidural, spinal, or general anesthesia may be used for control in the early postoperative period, and (3) assuring above-the-knee amputation. For the best functional results, it the patient that phantom sensation after a below-the-knee is desirable to keep the femur as long as possible. A longer amputation is common and that any discomfort in the foot stump improves the prognosis for prosthetic limb rehabilita- immediately after the operation period will vanish once he or tion and provides better balance for sitting and transfers. she begins walking again with a prosthetic leg. Healing potential, however, is lower with a longer stump; Ulceration of the skin over the transected anterior portion therefore, if the pelvic circulation is severely compromised, a of the tibia is another serious complication that may preclude shorter stump should be fashioned. successful prosthetic limb fitting. This complication is also Anterior and posterior flaps of equal length are marked on best managed through prevention, which depends on meticu- the skin. The flaps should be wide and long [see Figure 9], lous surgical technique. As noted (see above), the anterior and their apices should be centered on the line dividing the tibial crest must be carefully beveled and smoothed at the level of transection, and the tibia must not be transected more than 1 cm proximal to the anterior skin incision. With a standard below-the-knee prosthetic leg, weight is borne on the femoral condyles, the patella, and the tibial tuberosity. Breakdown of the stump can occur if weight is borne on the distal portion of the stump. Several decades ago, Jan Ertl described a tibiofibular synostosis designed to allow distal weight bearing; however, this technique has not been widely adopted.10  Shortly after the amputation, the patient should be encour- aged to start working on strengthening the upper body; upper-body strength is critical for making transfers and for using parallel bars, crutches, or a walker. In patients who have preoperative intractable ischemic rest pain, postopera- tive administration of epidural analgesia can break the cycle of pain. Once postoperative pain is adequately controlled, patients are taught to transfer in and out of a wheelchair. A compression garment is used on the stump once the sutures have been removed and the stump is fully healed. Prosthetic rehabilitation begins when the stump achieves a conical shape. Unfortunately, a number of patients who have undergone amputation for ischemia are unable to walk with a prosthetic limb because of comorbid medical conditions and general debility. In many cases, however, even if full ambulation is impossible, patients can maintain relative inde- pendence if the knee is salvaged by using a combination of a prosthetic leg and a walker for transfers and movement around the house.6 Above-the-Knee Amputation Figure 9 Above-the-knee amputation. Broadly based anterior and posterior flaps are created. The femur is   transected along the dashed line, at the apices of the skin Above-the-knee amputation is indicated if the lower flaps. The skin flaps and the level of transection of the femur extremity is unsalvageable and there is no femoral pulse. can be placed more proximally if clinically indicated. 05/08
  • 10. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 10 anterior and posterior muscle compartments. The posterior tension. The posterior flap is completed with an amputation incision is made first to minimize the presence of blood in the knife, and the specimen is handed off the field. operative field. The anterior incision is made second and All bleeding points are clamped and tied with absorbable carried through the anterior muscles in a plane parallel to sutures. The sciatic nerve is placed on gentle traction, the skin incision. The skin incisions are carried through the clamped, divided, and ligated, and the transected nerve is dermis, and the skin edges are allowed to separate and expose allowed to retract into the muscles. The deep fascia is approx- the subcutaneous fat; as in other amputations, they should be imated with interrupted absorbable sutures, with adjustments perpendicular to the skin surface so as not to undermine the made for any discrepancy in length between the two flaps. skin. The skin is approximated by placing interrupted absorbable If the superficial femoral artery is patent, the artery and sutures, with buried knots, at the dermal-epidermal junction vein are isolated and clamped after the sartorius is divided (interrupted subcuticular sutures). but before the remainder of the anterior muscles are divided. A nonadherent dressing is placed on the suture line and The femur is scored circumferentially. The soft tissues are covered with dry, fluffed gauze bandages. An aerosol tincture dissected away from the femur to the level of the apices of the of benzoin is sprayed on the thigh, the hip, and the lower flaps, and the femur is divided with an oscillating saw at abdomen. When the benzoin is dry, a cloth stockinette with this level. If the end of the resected femur extends beyond a diameter of 4 in. is stretched over the stump [see Figure 10]. the apices of the flaps, the wound cannot be closed without The cuff of the stockinette is cut medially at the groin, and a b c Figure 10 Above-the-knee amputation. (a) After an aerosol tincture of benzoin is applied to the thigh, the hip, and the lower abdomen, a 4 in. wide stockinette is rolled over the amputation stump. The cuff of the stockinette is cut medially at the groin. (b) The remainder of the stockinette is then rolled laterally up over the hip, and the cuff is cut on the lateral midline. (c) The two resulting strips of cloth are passed around the waist, one anteriorly and one posteriorly, and these strips are tied on the anterior midline to complete the dressing. 05/08
  • 11. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 6 VASCULAR SYSTEM 20 LOWER-EXTREMITY AMPUTATION FOR ISCHEMIA — 11 the stockinette is rolled laterally above the hip, where the cuff successful prosthetic limb rehabilitation. In dealing with this is then cut on the midaxillary line. This process yields two complication, prevention is far more effective than treatment: strips of cloth, one anterior and one posterior, which are once a flexion contracture at the hip becomes fixed, it is very passed around the patient’s waist and tied on the anterior difficult to reverse. If a patient is a candidate for prosthetic midline. limb rehabilitation, the traction weight mentioned earlier (see If the patient is a candidate for prosthetic limb rehabilita- above) can be very helpful. As soon as postoperative pain is tion, a traction rope is passed through a hole cut in the distal controlled, the patient should be taught to spend three peri- end of the stockinette and tied. The rope is hung over the end ods daily in a prone position to help extend the hip. He or of the bed and tied to a 5 lb weight; this step helps prevent she should then be taught exercises for maintaining range flexion contracture at the hip. of motion in the hip before prosthetic limb rehabilitation is The stockinette need not be removed for the wound to initiated. Flexion contracture of the hip is less of a problem be inspected. A window is cut in the distal end of the in nonambulatory patients; however, it can still lead to wound stockinette, and the gauze is removed. Once the incision has breakdown and chronic skin ulceration. been inspected, fresh gauze is applied, and the window in the Gottschalk noted that loss of the adductor magnus leads to stockinette is closed with safety pins. abnormal abduction of the femur. Accordingly, he proposed preservation of the adductor magnus and myodesis of the  transected muscles to the femur to improve the biomechanics Postoperative complications include bleeding, infection, after above-the-knee amputation.11,12 and failure to heal, all of which are likely to result in the need  for surgical revision of the amputation stump. Control of pre- operative infection and meticulous surgical technique and Once postoperative pain has abated, patients are mobilized hemostasis are necessary to prevent these complications. to wheelchair transfers. The prognosis for successful pros- Flexion contracture of the hip is a major complication thetic limb ambulation in patients undergoing above-the-knee of above-the-knee amputation. Such contractures preclude amputation for ischemia is very poor. References 1. Reichle FA, Rankin KP, Tyson RR, et al. in end-stage vascular disease. Eur Vasc Surg and mortality after lower limb amputation. Long-term results of 474 arterial reconstruc- 1992;6:321–6. Eur J Vasc Endovasc Surg 2005;29:633–7. tions for severely ischemic limbs: a fourteen 6. Nehler MR, Coll JR, Hiatt WR, et al. 10. Pinzur MS, Pinto MA, Smith DG. Con- year follow-up. Surgery 1979;85:93–100. Functional outcome in a contemporary series troversies in amputation surgery. Instr Course 2. Maini BS, Mannick JA. Effect of arterial of major lower extremity amputations. J Vasc Lect 2003;52:445–51. reconstruction on limb salvage: a ten-year Surg 2003;38:7–14. 11. Gottschalk F. Transfemoral amputation: appraisal. Arch Surg 1978;113:1297–304. 7. Toursarkissian B, Shireman PK, Harrison A, biomechanics and surgery. Clin Orthop Relat 3. Ellitsgaard N, Andersson AP, Fabrin J, et al. Major lower extremity amputation: Res 1999;361:15–22. Holstein P. Outcome in 282 lower extremity contemporary experience in a single Veterans 12. Gottschalk FA, Stills M. The biomechanics amputations: knee salvage and survival. Acta Affairs institution. Am Surg 2002;68:606–10. of trans-femoral amputation. Prosthet Orthot Orthop Scand 1990;61:140–2. 8. Aulivola B, Hile CN, Hamdan AD, et al. Int 1994;18:12–7. 4. Stewart CPU, Jain AS, Ogston SA. Lower Major lower extremity amputation: outcome limb amputee survival. Prosthet Orthot Int of a modern series. Arch Surg 2004;139: 1992;16:11–8. 395–9. Acknowledgment 5. Inderbitzi R, Buttiker M, Pfluger D, Nachbur 9. Ploeg AJ, Lardenoye JW, Vrancken Peeters B. The fate of bilateral lower limb amputees MP, et al. Contemporary series of morbidity Figures 1 through 10 Tom Moore. 05/08