Chapter Two, "General Principles of Amputation Surgery", by Douglas G. Smith, MD, from the Atlas of Amputation and Limb Deficiencies (1). Available with permission from the American Academy of Orthopaedic Surgeons.
Arms and legs, hands and feet: These unique and wonderful extensions of our bodies allow us to touch, to feel and to manipulate our environment. They provide us with the invaluable capability of propulsion and allow us to move freely throughout the world. The word ‘limb’ hardly captures the sum and substance of these magnificent structures. Loss of part or all of a limb will forever change how we move, touch, work and play. The individual who loses a limb faces enormous emotional, psychological and physical challenges. When an individual loses part of his physical self he may perceive himself as no longer whole. To survive he has no alternative but to supplement his newly altered physical body with modern mechanical prosthetics in order to regain lost function. This is how he will once again find peace and wholeness. One fantastic young lady, who only recently underwent a transfemoral amputation, recently advanced a revolutionary new vision. She would like to see medicine and science move from artificial limbs to replacement limbs. The replacement limbs would be so comfortable, natural and functional that limb loss would become much less of a event, on par with the loss of an appendix or a gall bladder (ref. Laura Willingham, PRS).
Amputation surgery severs all the varied tissues of the limb. Each tissue must heal in its own particular manner, and the knowledgeable surgeon considers each tissue’s unique role as he plots a reconstructive course. This careful calculation is essential to create the most functional residual limb possible. Limb loss is not only a major physical and functional loss; it also presents the patient with a matchless psychological and emotional situation. Our limbs are a major part not only of our physical being but also of our body image and our self-image. Losing a limb will forever alter all these aspects of the amputee’s life. Even if only a portion of the limb is removed, the brain will still perceive sensations, movement and even pain in the tissues no longer physically present. As Dr. Burgess has pointed out, no amount of psychological testing and evaluation can completely measure the effects of limb loss on a given individual. Only the amputee knows what it is like to lose a limb and how that loss impacts their life (ref to edition 1, 1981).
Amputation surgeons have a unique role and responsibility. When facing any surgical case, the surgeon must strive towards two primary goals, both of which are critical to the success of the procedure. The first goal is the removal of the diseased, damaged or dysfunctional portion of the limb. The second goal is the reconstruction of the remaining limb. Reconstruction must promote primary or secondary wound healing as well as create the most optimal sensory and motor end organ possible. The reconstructive nature of amputation surgery and the potentially positive impact that proper technique can have on an individual’s post-amputation function cannot be over emphasized. The success of every amputation surgery depends on the balance between these two main goals. To be effective, the amputation surgeon must understand not only surgical principles, but also all the aspects of healing, rehabilitation, residual limb physiology and the nature of prosthetic substitutes. Only through a comprehensive grasp of all of these elements of the amputation process can a surgeon truly become an expert and provide the best care for each patient.
The team approach to amputee rehabilitation leads to a more enlightened and successful healing, and it is important to remember that the surgeon is but one member of the amputation rehabilitation team. Communication between team members is essential. The surgeon can benefit from the wisdom and perspectives of the other team members throughout all phases of the amputation process. Other members will have insights on the pre-operative evaluation, during the operation itself, in the healing phase of the early post-operative period and all the way to the management of late complications long after the definitive surgery is complete. The surgeon would be wise to encourage the opinions of his teammates, and wiser still to take these opinions into his calculated and comprehensive consideration.
Levels of Amputation
Amputation is an extraordinarily broad term, covering the entire range of body-part loss. It covers the loss of part of a finger to an entire arm to chest-wall level, and from the loss of a toe all the way to the entire leg or pelvic area. Even above-pelvis, waist-level amputation is occasionally required.
The term ‘amputation’ is typically used to describe the removal of all or part of a limb, but technically it is more precise to reserve this term for the process of limb removal by dividing through one or more of the bones. The term ‘disarticulation’ is more precise for the process of removing a limb between joint surfaces. Each particular site throughout the upper or lower limbs has individualized characteristics of bone shape, nerves, musculature and blood vessels, as well as particular muscles, skin and soft tissue envelope structures available for padding, protecting, and reconstruction. An intimate understanding of the anatomy of all these sites and the various attributes and characteristics that impact healing and prosthetic rehabilitation are important when deciding where and how to amputate.
Upper and lower extremity issues are very different, and deciding between limb salvage versus amputation requires different considerations for upper versus lower extremity injuries. For example, the upper extremity is not weightbearing and can function with minimal sensation. Cases show that even if the salvage of an upper limb results in only minimally assistive function, this salvage is often better than the prosthetic substitutes available on the market today. In contrast, for the lower extremity, weightbearing is mandatory and salvage often functions poorly if it does not provide enough protective sensation. In contrast to an upper limb, a salvaged lower limb must hold up to the demanding forces of walking and weightbearing in order to achieve functional results superior to prosthetic substitution.
If salvage is impossible and amputation is the best course of action, important differences exist in amputation level and technique between upper and lower extremities. During the preoperative, operative, and post-operative phases it is important to educate the patient as well as all others involved with their health care to the goals and differences between upper and lower limbs. Traditional amputation levels were developed over the ages through a process by which surgeons ‘passed down’ knowledge and lessons learned concerning specific techniques. The best techniques provided the fastest healing and best-padded stump, as well as a stump that could best retain its physiology. Specific amputation levels were determined by understanding what locations best adapted to prosthetic substitution.
Predictably, techniques and methodology are always subject to opinion, and modern day medical controversies still exist concerning amputation. It is to be expected that all surgeons do not necessarily agree on the best course of action in specific cases. In instances of lower limb injury for example, both the processes of amputation at the ankle and knee disarticulation have specific positive and negative attributes. This makes the selection of these two particular lower-limb amputation levels controversial, not because the techniques are questionable - most surgeons agree that the techniques are practicable - but because success rates and ease of prosthetic fitting remain disputed. Because success rates and ease of prosthetic fitting are disagreed upon, most surgeons fall into one of two camps concerning the usefulness of these procedures. However, in the past decades, great improvements in design and engineering of prosthetic devices have made these amputation levels much more successful. Today, even the more conservative surgeons are more apt to consider ankle-level amputation and knee disarticulation viable surgical procedures.
In each particular patient case, the surgeon faces many decisions and has considerable latitude exercising personal judgement. Weighing and measuring all options requires thoughtful and thorough consideration. The initial and most basic decision is the choice between amputation versus attempt to salvage. Once amputation has been decided upon as the course of action, preoperatively the surgeon must determine the most distal level of amputation still compatible with wound healing and subsequent satisfactory prosthetic fitting. Selecting this level requires detailed clinical evaluation combined with laboratory and radiographic studies. Except for those few levels that will be specifically discussed in later chapters, in most amputations the surgeon will select the most distal level consistent with successful removal of the diseased state. The surgeon must bear in mind the degree to which the remainder of the appendage can provide a well-healed, non-tender physiologic residual limb. Conservation of residual limb length is a basic principle of modern amputation surgery.
In determining amputation level, the goal is to create the best environment for the rapid return of mobility and function. The environment for wound healing should be maximized in part by evaluating the patient’s nutritional status. In the case of diabetics, controlling blood glucose levels is essential. Minimizing edema, optimizing vascular inflow, eliminating bacteremia and the appropriate use of antibiotics are other factors essential to determining amputation level. Surgical procedures and rehabilitation must be coordinated to minimize de-conditioning. Modern amputee management involves a multidisciplinary approach to address these comprehensive issues. Medical, surgical, social, rehabilitative, prosthetic and economic factors all play an important role in each individual case. Planning for optimum function in amputation surgery consists of preoperative, operative as well as short- and long-term postoperative goals.
When amputating, the general principles of plastic and reconstructive surgery apply to incision location and placement of scars. While a painless, pliable and non-adherent scar is a primary goal in most surgeries, in amputation the prosthetic interface and socket design can make the location of the scar of increased importance. When uncomplicated primary healing results in scars that are nontender, pliable, mobile, and durable, then location does not really matter. However, when healing is less than ideal, and scars become adherant, tender, thin and non-durable,or thick and promenent; then location matters a great deal. The wise surgeon, when possible, plans scar placement appropriately to minimize future issues just in case less than perfect healing results.
The amputation site in the lower extremity functions as the patient’s foot, and as such, requires reconstructive design to provide a durable interface for walking and the transfer of body weight. The amputation site in the upper limb becomes, in essence, the patient’s hand. The skin should therefore be managed as carefully as it would be in hand surgery to maximize a successful outcome.
When closing, fasciocutaneous flaps should be made as broad-based as possible to maximize profusion and avoid compromise of blood supply. The skin closure must be without tension but it cannot be redundant. Particularly in the dysvascular limb, care must be taken to avoid separating the skin from the underlying subcutaneous tissue and fascia. Pressure sensitive areas exist in residual limbs and care should be taken not to place scars over a bony prominence or the subcutaneous bone. The more skin surface available for contact with the prosthetic socket, the less pressure will be applied to each unit area of skin surface. A cylindrical shaped residual limb with muscular padding presents fewer skin problems than the bony, atrophic tapered residual limb.
Along with fasciocutaneous flaps and free flap techniques, skin grafts are a viable option in modern amputation surgeries and prosthetic fittings. It is possible for split-thickness skin grafts to hold under the forces applied by a prosthesis, but grafts will be most successful when not adherent to bone. Application of the graft over a cushioned, mobile muscle bed is ideal. However, without the fine layer of subcutaneous fat to absorb shear, grafts are not as durable as normal skin. Fortunately, liners made of elastomeric materials have improved prosthetic success for individuals with scar and skin graftings. This is of particular help for burn victims, as amputations in burned limbs often require skin grafts. The grafted skin and burn tissue will become more pressure tolerant over time if the shear and skin stretch are moderated by careful prosthetic fit and the introduction to the prosthesis is gradual. The amount of time wearing the prosthesis, the amount of force applied and activity levels must be carefully controlled and slowly calibrated forward. Over a period of many months the badly burned limb with amputation and free graft coverage may develop a tolerance that can provide optimum function. Such patients can often use prosthetic devices successfully and thereby avoid amputation at a higher level.
Skin problems remain a major concern for amputees throughout their lives. The amputation surgeon needs to be familiar with the many different types of short and long-term skin and wound healing problems. Post-operative infections, wound dehiscence and partial skin flap failure occur with unfortunate frequency in the short term healing process. Contact dermatitis, skin irritation, reactive hyperemia, callus formation, verrucuous hyperplasia, folliculitis, epidermoid cysts, hidradenitis, fungal infections and chronic breakdown are potential long-term skin ailments. Complicated skin problems often require multidisciplinary approaches requiring prosthetists, wound care specialists, dermatologists and the original surgical team.
Muscle makes up the bulk of the residual limb soft tissues. The amputee with a muscular, well-padded and balanced residual limb is less prone to chronic pain syndromes. Maximum retention of functioning muscles is essential to provide the residual limb with effective strength, size, shape, circulation, metabolic exchange and proprioception. Proper muscle function depends on the anatomic origin and insertion of the muscle. Without fixed resistance against which a muscle can forcefully contract, progressive weakness and atrophy develop. Distal muscle stabilization is a primary principle of amputation surgery. Whenever possible the sectioned muscle should be attached and stabilized in order to retain muscle function and to improve coverage and distal padding of the bone.
Historically, four types of muscle stabilization can be accomplished via surgical means. These include simple myofascial closure, myoplasty, myodesis and tenodesis. These closures have varying degrees of efficacy and efficiency in terms of muscle stabilization and in preserving function.
The first of these techniques, myofascial closure, encases the transected muscle by closing the outer fascial envelope over the top of the muscles. Myofascial closure in and of itself is not an effective means of muscle stabilization as it provides only minimal stabilization for the most superficial muscles, and provides inadequate distal attachment of the muscular tissue to the bone. It is primarily used when severe ischemia prevents more effective means of distal muscle fixation. However, even in the vast majority of today's dysvascular and diabetic amputations, more effective muscle stabilization is technically possible, and a wise endeavor.
In most diaphyseal amputations the muscle bellies themselves are transected, making it more difficult to attach the muscle to the bone than if their thicker distal fascia, aponeurosis or tendon were still present. This is the circumstance in the majority of transfemoral or transtibial amputations. Myoplasty, the second technique, is one by which the surgeon brings the muscles over the end of the bone and sews them to opposing muscle groups. Unfortunately, unless these muscles become firmly stabilized by scar tissue, the attachment can work antagonistically as a muscular sling, sliding back and forth over the distal end of the bone. This motion of muscle sliding over the bone is not good. It often creates bursal tissue and discomfort, both of which are easy to identify upon examination. Motion and an accompanying crepitance will be palpable over the end of the bone on physical examination. Because of the frequency of these complications, simple myoplasty is not recommended and the surgeon should instead attempt to secure the tissue directly to the distal end of the bone.
If the muscle groups themselves are attached directly and securely to the periosteum or the bone, it is called myodesis. In myodesis, the deepest layers of muscle are typically secured directly to the bone, while the more superficial layers of muscle are sewn to each other as a myoplasty. The myofascial envelope is then closed over the top of this muscular reconstruction.
A final muscle stabilization technique, tenodesis, is very secure but frequently anatomically impossible. Tenodesis involves the firm distal attachment of the severed tendon down to the bone, and is the most physiologic and effective means of muscle stabilization. It is possible only when the muscle belly itself is not transected and the tendon is intact. Tenodesis is most commonly used in disarticulations, and is the primary method in knee disarticulations in which the patellar tendon is secured to the origin of the cruciate ligaments on the distal femur. Whenever anatomical circumstances permit, distal attachment of the muscles, tendon, fascia or aponeurosis directly to the bone should be performed.
To optimize effective residual limb muscle activity, the muscle should be stabilized under near physiologic tension. Correct muscle tension varies from case to case, and the primary determinants of appropriate tension level remain somewhat amorphous. There is no set of hard and fast rules. Studied clinical judgement and adherence to the principles of muscle tension provide the best results. Determining correct muscle tension in an amputation is similar to determining the tension of tendon transfers in the hand or foot. In general, most surgeons err on the side of too lax rather than too tight. Unfortunately, it is entirely possible that when stabilizing muscle groups the surgeon can apply excessive or unbalanced tension, causing sever pain to the patient. One example of accidental implementation of excessive tension occurs if a surgeon advances the quadriceps under too far, a scenario that leads to hip-flexion contracture. Though it is difficult to establish a solid set of guidelines when performing muscle stabilization, stabilization is an essential element of amputation surgery and the reconstructive process.
The management of sectioned nerves remains a controversial aspect of amputation surgery. The free end of a divided nerve heals by forming a neuroma. This intertwined mass of scar and nerve tissue can be painful to pressure, stretching and other types of physical manipulation. Even when completely undisturbed, electrical potentials may arise within the mass, causing negative local and distant sensory and motor phenomena. These sensations can be bothersome and painful to the amputee. While numerous techniques have been devised in order to minimize neuroma formation, none have proven uniformly successful. Some methods have included cauterizing the nerve ends using chemicals or heat, burying the nerve in bone, encasing the nerve in impervious material, ligating the nerve or injecting the nerve with a variety of chemicals. Other methods include sewing the sectioned nerves to other nerves or sewing them back onto themselves, thereby creating a nerve loop. Others methods entail simply dividing the nerve and allowing it to retract.
Since neuroma formation is to some degree inevitable, the generally accepted management procedure is drawing the nerve distally, sectioning it and allowing it to retract away from areas of pressure, scarring and pulsating vessels. Ligation of a nerve is indicated if the nerve is likely to bleed, as is the case with the sciatic nerve. When a nerve is severed in the amputation process, the surgeon’s goal is to position the nerve ending in a well-cushioned soft tissue site away from the incision and any scar tissue. There it will not be irritated by traction, pressure from the prosthetic socket or any other potential sources of contact.
Neuromas in very scarred and adherent areas are the most symptomatic. When working in these areas the surgeon should apply moderate tension to the nerve and section it cleanly, allowing it to retract away from the site of amputation and into the proximal soft tissues. This circumvents the distal end of the nerve scarring to the surgical site where traction and pressure are more likely. Traction on the nerve at the time of sectioning should not be excessive, as too much tension can lead to proximal pain and neuropathy. As with the conservation of muscle tissue in the residual limb, the surgeon’s goal is to retain and employ as much of the useful remaining nerve function. Care should be taken to avoid disturbing the nerve fibers enervating the remaining limb structures, particularly those enervating the muscles and skin.
The theory that proximity between nerves and blood vessels causes symptoms is undergoing renewed interest. When a nerve is unintentionally ligated together with a pulsing vessel a situation may result in which the nerve endings sense the vessel’s cadence and become a source of throbbing and pain. In the transtibial amputation, the two most common nerves ligated with a vessel are the deep peroneal nerve and the tibial nerve. This happens if the deep peroneal nerve is not separated off the anterior tibial vessels, or the tibial nerve is not separated off the posterior tibial vessels. At revision surgery, the separation and division of the nerve away from the re-ligatated vessels can relieve the throbbing. Extra caution concerning the nerves should always be exercised in the high-level upper extremity amputations. Unfortunately, particularly in surgeries involving the brachial plexus, nerves are often accidentally included in the ligatures with the axillary vessels.
Adequate hemostasis and the management of blood vessels and bleeding sites is of utmost importance in amputation surgery. Major arteries and veins should be isolated and ligated securely. Double ligation of large arteries should be standard, especially when the amputation is carried out in the presence of normal blood supply. Cauterization should be reserved for smaller bleeding points only. The central artery of a large nerve such as the sciatic nerve can be a troublesome source of bleeding. Excessive bleeding in this instance can be avoided by ligation with absorbable suture. Bleeding from the sectioned bone end is best controlled by pressure. Occasionally critical intra-osseous vessels will require cauterization or a small amount of bone wax. However, bone wax is in actuality only very rarely required. Bone wax should be used as infrequently as possible because it remains as a foreign body within the surgical site and can lead to potential complications.
Adequate blood supply to the distal tissues and to the wound margins facilitates proper healing. For appropriate blood supply, the surgeon should avoid dissection of the subcutaneous tissue and keep the muscular investing fascia with the skin whenever possible. Dissection should not damage the proximal blood vessels. Skin or preferably fasciocutaneous flaps, even when broad based, should be developed with careful attention to blood supply. This is especially important for patients suffering from vascular disease and diabetes. Careful attention to hemostasis and managing the vascular supply to the flaps can make the difference between healing and failure, particularly when blood supply is marginal.
Amputation sites are usually drained surgically with suction drainage, as sectioned muscle and bone can often result in a surgical site that is not, and cannot be perfectly dry. A post-operative hematoma can be a major complication that predisposes the patient to infection. In worst case scenarios, hematomas result in delayed wound healing or complete failure. If a large post-operative hematoma is identified the patient should be returned to the operating room for evacuation, irrigation and debridement. Complete hemostasis should be attained before leaving the operating room the second time. Revision surgery and higher-level amputation have been necessitated due to hematoma formation. The surgeon should do his utmost to avoid this, but if a hematoma does form, it must be identified early and treated quickly.
The forces traveling between prosthesis, residual limb and the remaining body are in large part transmitted through the retained bone in the amputated limb. Diaphyseal bone should be sectioned at the length consistent with reconstructive soft tissue closure. Managing the edges of severed bone is essential to pain-free healing, and the sharp cortical bone edges and irregularities should be carefully contoured and rounded. In each amputation case, bone transection and shaping should take into account the available prosthetic devices for that particular level of amputation. Preoperatively, the surgeon must be sufficiently familiar with the most frequent bone related problems at each level in order to minimize future woes. For example, in transtibial amputations, anterior beveling to remove the distal corner of the tibia is one method of proactive management. Removing the distal plantar corner of the calcaneous in a hindfoot amputation is another example of a preemptive strike against future complications.
Proper foresight and attention to bone preparation eliminates potential areas of high pressure at the bone socket interface. Under normal circumstances there are no sharp, angular surfaces in the palm of the hand or the sole of the foot, and retained distal bone in these areas should come as close to this natural state as possible. Occasionally in disarticulations, it is a good idea to narrow the distal metaphyseal flare of the bone to prevent an overly bulbous and enlarged distal stump. For example, in the Syme ankle disarticulation surgical contouring of the distal tibia and fibula are mandatory, as a bulbous, and non-contoured distal stump will cause increased difficulties in prosthetic fitting. However, in general bone resection is kept to the minimum in most disarticulations.
Protocol for the successful management of the periosteum is less concretely defined. In instances of diaphyseal amputation, children tend to form new bone with periosteal and endosteal bone overgrowth at the end of the amputation. Capping the end of a diaphyseal amputation with osteochondral bone surface (often obtained from part of the amputation specimen itself), has been shown to minimize bony overgrowth. These specific techniques are addressed in the pediatric chapters.
Diaphyseal bone does not exist without an outer cover of cortex in its natural state. Thus it is intuitively physiologic to seal the end of the bone following amputation, and techniques have been refined for performing an osteo-periosteal bone cap over the end of diaphyseal bone. However, even without a surgical osteo-periosteal flap, the end of the bone naturally heals by formation of bone callous and fibrous tissue. When a periosteum cuff is available it may be sutured over the end of the bone, but excessive use of periosteal strips can cause problems. As occasionally seen in traumatic amputations or when the periosteum is circumventially peeled off the bone before sectioning, the residual periosteal strips can slowly form irregular bone spikes. These spikes or bone spurs can cause painful pressure points for the amputee. The surgeon should be aware of this potential problem in order to minimize its occurrence.
The standard protocols for skin closure in any other surgery also apply to closing the wound following an amputation. Dead space should be eliminated and drain systems used when necessary. When closing the wound, opposing tissue layers are sewn under physiologic tension, and care must be taken so that the final closure is neither too light nor too loose. As with all surgery, careful judgement is necessary in the selection of suture and closure technique, and the amputation surgeon must be aware of the options and differences between various techniques. Many patients have only marginal blood supply and the utmost surgical care and technique is required to maximize their wound healing potential.
If primary closure of the wound is not advisable, amputation should be carried out in two or more stages. An initial amputation may be done to provide adequate drainage of infection. This is the recommended course for a preliminary open ankle disarticulation involving a septic patient with a severely infected, non-salvagable diabetic foot. Patients presenting with such a scenario are frequently febrile and bacteremic. The initial open amputation helps to control the infection, eliminate the bacteremia and provide a safer wound environment for a definitive amputation at a later date. Leaving the bone long and avoiding transecting the muscle bellies minimizes the post-operative swelling and edema that often complicates mid-diaphyseal open amputations. When left long, the bone can act as an internal splint, protecting the remaining soft tissue. This will facilitate the later definitive amputation.
Often times a contaminated, open amputation is the result of the original traumatic injury. Contaminated amputations can be treated in a similar fashion to other open amputations. As always, first and foremost the amputation is formed with consideration as to how it will eventually be shaped and closed. Often in trauma cases there is an intermediate zone of tissue. This zone usually requires time to either recover or demarcate, and multiple secondary surgeries can be required before it becomes evident if the involved tissue is viable or must be removed.
Open amputations are not guillotine amputations. In the past the term ‘guillotine amputation’ was commonly used, but both this wording and the particular technique it describes should be avoided. In times of war, guillotine amputation was used to avoid infection. All the different tissues were transected at the same level, much as a guillotine blade would sever a limb. In a guillotine amputation, no flaps were fashioned, no muscle for myodesis was retained and no fasciocutaneous closure was planned. The post-operative plan following guillotine amputation was not to perform a secondary closure, but instead to apply skin traction, daily dressing changes and prolonged wound care. Distal healing with skin traction resulted in fragile, thin, distal coverage that has poor durablity. An eventual revision would often be performed many months later. The guillotine technique is no longer recommended. Even in instances of grave trauma, open amputation with a thoughtful plan for closure is a better option.
The general principles of primary amputation also apply to revision amputation. Revision is necessary if the primary amputation fails to heal, or else if the residual limb is unsatisfactory for prosthetic fitting. Revision may also be necessary if the residual limb does not serve the patient’s functional requirements. With advances in prosthetic devices and interfaces, limbs once historically difficult to fit can now be accommodated for reasonably well. Unfortunately, many modern-day amputations are still poorly done, and these will either develop complications during the healing process, or else require revision surgery at a later date. Better education, more research, and additional refinement of surgical technique are the ways to avoid unnecessary revision amputations.
Revision amputation for pain issues is a viable option only when the etiology of the patient's pain is clearly identified. Such pain problems that are amenable to surgical treatment include redundant tissue, in-folded skin, painful scars, bone prominence, bone spurs, heterotopic ossification, failure of myodesis, distinct and identifiable symptomatic neuromas and some chronic skin conditions, such as epidemoid cysts and chronic skin break down or ulceration. Surgery specifically for the treatment of phantom pain, without clear pathologic etiology, has not been successful.
When revising an amputation the surgeon manages each tissue type with the same goals as when proceeding with the primary amputation. In revision amputation cases, the muscles may be scarred and atrophic. Unfortunately muscle stabilization, while technically possible, is less effective with each successive operation. None the less, muscle stabilization should always be considered an essential goal of secondary reconstruction. Some muscle stabilization, limited though it may be, is better than none at all.
Most other surgical procedures are considered complete when the wound is healed. This is not the case in amputation surgeries. Unless the healed residual limb is fitted with an appropriate limb substitute or prosthesis, no functional restoration is possible and the process remains unfinished. The empty sleeve or empty trouser leg is an arresting testimony of incomplete postoperative management. Since postoperative care requires the residual limb to interface and direct the prosthetic device, surgical responsibility ends only when maximum functional restoration has been achieved. The surgeon must always remember the ultimate goal: to replace the limb and restore life.
The primary goals of post-surgical amputation management include prompt, uncomplicated wound healing, control of edema, control of postoperative pain, prevention of joint contractures and rapid rehabilitation to optimum levels of activity. Before attempting prosthetic fitting, the residual limb changes shape and volume, muscles re-adapt and the limb "matures". Time and maturation are necessary in order to avoid a painful mismatching between the shape of the residual limb and prosthetic socket. Without proper patience and preparation, a prosthesis can be fabricated too early, only to become quickly result in a socket that is incompatible with the changing shape of the stump. In these lamentable cases, the patient is left with a fancy, expensive and high technology limb that is useless to him, because it does not fit. To be refitted, the patient often has to wait for approval of a new socket by a funding agency. Once he has approval, he has to go through the time-consuming process of another socket fabrication, reassembly and realignment. It is far wiser to instead to use progessive protocols that allow frequent modification, adjustment and replacement of check sockets or other temporary devices. These protocols can allow ongoing rehabilitation combined with appropriate management of the healing process and inevitable volume changes before definite fitting and thereby avoid this all too frequent and very frustrating scenario.
Compressive wound dressings have long been recognized as essential for controlling swelling, minimizing post-operative pain and promoting stable limb volume. Though nurses, therapists and other providers are carefully trained in techniques of residual limb wrapping and bandaging, these techniques are not always easy or problem free. Soft dressings are sterile, compressible and cover the wound beneath a layer of elastic bandages. The bandages support the amputation site under compressive pressure, but care must be taken that they not be so tight as to lead to proximal constriction or a tourniquet effect. While an unquestionable benefit to the healing process, elastic bandages need frequent changing and require close monitoring to maintain the correct amount of pressure. Proper soft dressing protocol requires careful judgement, technical skill and vigilance. The advantages of soft dressing management include the apparent ease of application, and because they provide easier access to the wound, the surgeon can inspect the wound site frequently as it heals. However, complications can arise from poor wrapping of the residual limb, and it is not uncommon to develop joint contractures. When used exclusively, soft dressings frequently make muscle conditioning and pain control more difficult. Even though many surgeons consider simple soft dressings outdated, in comparison to the semi-rigid and rigid postoperative prosthetic techniques available, they are still the method preferred by many amputation surgeons.
For many years, both open and closed amputations have been treated by the early application of rigid dressings. This technique was first described immediately following World War I, and we are fortunate that these first experiences were documented in comprehensive writings charting both clean and infected lower limb amputation procedures. Wilson first published his experiences with early weight bearing and the treatment of amputations of the lower limbs in 1922. He advanced further into post-operative prosthetic care when he applied the first simple functional prosthetic units to the rigid dressings, and allowing his patients to ambulate with some degree of weight bearing on the healing amputated limb. Wilson’s methods received little attention until surgeons in France and Poland resurrected his work following World War II. At the end of World War II, thousands of soldiers were left with unhealed or poorly healed amputations. Given this increase in patient population, Drs. Berlemont in France, Weiss in Poland and later Burgess in the United States revived medical interest in the use of rigid dressings and the refining of early postoperative prosthetic techniques.
Injured tissues heal best and are less painful when supported and placed at rest. When the injured limb or amputation site is immobilized and the appropriate local pressure and elevation protocols are applied, the inflammatory response and edema associated with early healing is minimized. Immobilization, application of gentle distal pressure and infrequent dressing changes are tenets of good post surgical care. It is essential that each new generation of amputation surgeons be schooled on the importance of these tenets. Curiosity on the part of the surgeon can prompt overly frequent dressing changes and unnecessary inspection, and these practices generally do more harm than good. It is unfortunate that forthright principles of safe, sterile surgery are often over looked or abjectly ignored in these modern days of miracle drugs, magical wound ointments and medicinal gels that promise the impossible.
Rigid dressings can be fabricated using a variety of materials, including conventional plaster of Paris, elastic plaster of Paris, thermoplastic materials, and any number of other splinting materials. The dressing is applied at the end of surgery and is typically changed in intervals of five to fourteen days. Proper rigid cast protocol requires a therapeutic degree of terminal pressure while promoting a sterile, dry wound surface with no restrictions to hinder circulation. No proximal constriction should be applied to the dressing and the dressing must be adequately suspended to maintain distal pressure. Maintaining distal pressure is aided by means of a compressible material placed at the site of surgery, such as close-cell foam or distal end pads. Suspension is initially managed by molding the cast as it sets and is later reinforced by the devices such as waist belts or shoulder harnesses. Careful attention to suspension will minimize the distal ‘falling away’ of the cast, a process by which the cast slips down away from the end of the stump. When a cast falls away, terminal edema can develop, often with dire results. At this point in the healing process, patients should try straight leg-raises and towel pull exercises in order to provide intermittent pressure and control edema.
The primary objection to the rigid dressing as a postsurgical form of management is that the dressing itself prohibits frequent inspection of the operative site. However, that rigid dressing prevents frequent inspection of the wound site actually proves to be advantageous. Any experienced surgeon knows that an operative site heals best when properly supported, undisturbed and uncontaminated, and the rigid dressing promotes this environment. However, unusual pain, temperature, leukocytosis or other evidence of complications does require cast removal and wound inspection, which is indeed more difficult with a rigid dressing.
Some surgeons are daunted by the rigid dressing application process, but while application requires skill, it requires neither more nor less skill than the application of a soft dressing and supportive wrap. In comparison with soft dressings, rigid dressings have the advantages of improved patient comfort and easier mobility, as well as an improved wound healing environment. Regardless of dressing choice, amputation surgeons must have a firm grasp of modern post-operative amputation management and the proper application of postoperative dressing techniques.
The Immediate Post-Surgical Prosthesis
The immediate postoperative prosthetic device can serve as a socket and temporary prosthetic limb in both upper and lower extremity amputations. There are tremendous physical and psychological rehabilitative advantages to applying a prosthesis immediately. Provided with a replacement limb immediately following surgery, the patient avoids a limbless period and therefore some degree of functional restoration begins immediately. The patient’s general physical and mental state benefit from early physical activities. Comparative studies show less patient pain and faster patient mobilization in cases in which postoperative prostheses were employed immediately. The overall amputee rehabilitation period, including hospitalization and the time allotted for limb maturation, are shorter with immediate fit systems. During this period, the encouragement and enthusiasm of the amputation team should not be underestimated. Positive voices and encouragement are essential in directing the patient’s rapid return to regular activity levels.
Although some of the benefits of the immediate fit systems have not been statistically documented, positive experiences reported world-wide support many of the assertions made by its advocates. Areas of disagreement concerning these protocols center on the injurious effects of early function, particularly limited weight bearing and its subsequent effect on wound healing. Some surgeons feel that as with rigid dressings, early application of a prosthesis limits access to the surgical site, thereby preventing inspection and the ability to identify infections early. The major concern associated with immediate fitting is potential tissue damage and wound break down when excessive stresses are applied to the amputation site early on in the healing process. In general, some distal intermediate stress reduces edema and in many circumstances facilitates early healing. Tissue damage can occur, but if the surgeon proceeds on a case by case basis, he can circumvent this trouble. Caution and experience show that early weight bearing must be individualized according to the patient’s skill, understanding and ability to comply. As always, the surgeon must take into account the particular wound and the circumstances of the healing environment.
In addition to traditional casting techniques for immediate prosthetic devices, prefabricated and custom fabricated devices are available on the market today. The makers of these devices emphasize that rehabilitation and the return of function is the primary goal of treatment.
The First Year of Amputee Care
It is essential that the amputation surgeon be familiar with the course of amputee care and the elaborate nature of the prosthetic fitting process (ref Fergason, Smith). The surgeon must understand that the first year of amputee care is very different from the following ones. Because this first year is so different, what is useful in terms of components and prosthetic technology will change radically after the limb is mature and the patient’s activity level has increased. For example, traumatic amputees are typically younger patients with more muscle mass than commonly seen in the dysvascular and diabetic amputee group. They often suffer more swelling, and have more dramatic volume changes in the residual limb. This can make the first year of socket fitting particularly difficult as the volume of the residual limb is changing dramatically.
It is the amputation surgeon’s job to help supervise prosthetic care. When a leg is swollen and not fully mature, even if the patient and the prosthetist are pushing, the surgeon must resist the urge to form a definitive prosthetic socket too early. The intermediate time period is essential to the healing process, and impatience will only cause later disappointment. One especially frustrated patient had five definitive sockets made the first year following amputation. Following each successive failure, by the fifth socket his insurance provider refused to fund further prosthetic care just when he needed it most. Thanks to impatience, ill-timing and poor decision making by all parties involved, the patient was ultimately left with a prosthesis that did not fit, and a device he could not use. This is far from the appropriate standard of prosthetic care, and scenarios like this should be avoided at all cost. Similarly, it is a grave disappointment when a patient has limited prosthetic funding and the funds are exhausted too early in the course of prosthetic care. In a worst case scenario, the patient has a prosthetic device that looks great and has high tech components but no longer fits, and funds are no longer available to correct the situation. Patience and financial caution should be taken to avoid this predicament.
Reinforced multiple check socket protocols have proved very successful. They allow the patient to walk on each more-or-less temporary socket for two to eight weeks. Ambulatory activity in a check socket or temporary socket can help relieve edema over several months. Pelite liners are also an excellent option for the first socket fitting. Instead of fabricating a brand new socket, the Pelite liner can be padded in appropriate locations and thereby specifically adjusted to take up changes in volume in the appropriate location, thereby saving both time and money.
Typically when a recent traumatic transtibial amputee loses volume they suffer redness and pain at the distal end of the residual limb. The first step to remedy pain is to increase the ply and number of socks to modify fit. The second step is to pad the anterior-medial and the anterior-lateral tibial flair regions of the socket or the liner. These are the regions that support the tibia and push it away from the front of the socket, thus protecting the distal end. Padding can provide a successful fit with fewer socks. When volumes decrease more substantially, the posterior region of the socket can be padded or the tibial regions can be padded a second time. It is not uncommon to pad the liner up to four times before fabricating a new socket. Padding techniques save time, keep the course of rehabilitation smooth and continuous and prevent the hassle of re-authorization for a new prosthetic limb until absolutely necessary.
The elastomeric liners recently introduced on the prosthetic market have gained in popularity. Soft and pliable, these liners have immediate tactile appeal to the amputee and to the provider, but they can be problematic because they can cause skin reactions and are not universally tolerated by every patient. Complications reported include skin irritation, constriction and distal traction edema. One randomized study revealed that patients might actually ambulate less in the elastomeric locking liner systems than they do in traditional systems (ref Coleman). While many protocols have been advanced to use elastomeric liners and total contact socket shapes early in the post-operative period, these systems can be more dificult to frequently adjust and modify than other systems. Personally, I do not typically use elastomeric liners during the first year of care, as the changes in residual limb volume are too dramatic to make fittings routinely successful. Elastomeric liners can be appropriate for select cases in which very fragile soft tissue or scarring is involved, or traditional systems have failed. In these instances a pelite liner can be fabricated to fit over the locking liner and can allow padding and adjustments to take up the volume changes. Unfortunately, after 12 to 18 months many patients are transitioned into a new suspension system or socket shape without the benefit of actually testing or trying the proposed change. Again, ambulatory check socket protocols allow the patient two to eight weeks to decide if the change is indeed beneficial. These protocols can avoid the not infrequent scenario where a patient is "stuck" with a "new and different" system that sounded very appealing, but in reality was not successful for them.
Choice of Prosthetic Components
Many young traumatic amputees are adamant about obtaining the highest tech prosthetic components for their prosthesis. The prosthesis becomes a part of their body and their desire for the finest is understandable. However, many of the high tech components are not optimal for the first year of amputee care. Some of the highest-end foot and ankle components are actually too stiff for the first 6 to 12 months of ambulating. Other less technologically deluxe components actually make adapting to the prosthetic device easier. A new prosthetic prescription should only be generated after the amputee has established a steady symmetric gait, can engage in impact activities and is ready to advance to a higher level of activity. He should be able to maneuver barriers, manage stairs and negotiate inclines and ramps. This typically does not happen until between months 9 and 18. Only at this point is a new, higher-tech prosthesis useful. The old prosthesis can be refurbished to become a spare limb or a water limb.
It is essential that the thoughtful amputation surgeon understand the entire course of the amputation process, from the initial emergency room visit to the final selection of the perfect prosthesis. As devastating as it is for the patient, amputation will always be a difficult and a complex process for the surgeon as well. It asks the surgeon to successfully balance exacting surgical technique and knowledge, his intimate familiarity with the entire course of amputee care and his human understanding of each of his unique patients. Remembering the young woman’s vision at the start of this chapter, we think not of artificial limbs, but instead of replacement limbs. The surgeon capable of making an amputation successful, can indeed help make the patient whole.
Much of this material was updated from Ernest M. Burgess (deceased September 2000), Atlas of Limb Prosthetics - Surgical and Prosthetic Principles, Edition 1, 1981.
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