Amputation of the upper extremity takes its toll on both the patient and surgeon. The patient is devastated at the prospect of life with a disability and laments the potential loss of the independence we all take for granted. For the surgeon, the toll is much less, but feelings of sympathy and regret remain, as we wish we had another option. Nonetheless, it is important that surgeons who care for patients with hand and upper extremity injuries have an appreciation of the finer points of amputations. In addition, they should have a comfortable understanding of the treatment goals in postoperative rehabilitation and restoration of upper extremity function to maximize outcomes.
Major Limb Amputations
Although the amputation of a digit is by far more common, major upper extremity amputations account for up to 25% of all amputations. In the United States alone, approximately 41,000 people underwent transradial amputations in 2005. This prevalence has risen from previous estimates because of improved trauma and critical care medicine, which is preserving the life of severely injured patients; it is likely to continue to rise due to an aging population of patients with a higher incidence of diabetes and vascular disease. The effects of an upper extremity amputation are significant and greatly impact the quality of life. Up to a third of patients who undergo amputation of an upper extremity require a change in occupation, and almost two thirds discontinue vocations and hobbies as a consequence of the amputation.
The technical principles of upper extremity amputations are fairly consistent, regardless of the indication for surgery or level of amputation:
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Preservation of functional residual limb length
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Durable coverage of the residual limb to allow for long-term prosthetic use
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Prevention of symptomatic neuromas
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Prevention of adjacent joint contractures
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Early prosthetic fitting (golden period)
Indications
Unlike in the lower extremity, the majority of upper extremity amputations are performed as treatment for acute trauma. In Scandinavia, up to 90% of upper extremity amputations are trauma related. Amputations may be performed acutely when the hand surgeon believes that the functional potential of the salvaged limb would be substantially worse than that of a prosthetic limb. At times, the surgeon will elect to perform multiple operative procedures in an attempt to salvage a hand or extremity but is unsuccessful in these attempts. Such attempts to salvage a severely damaged limb may even be detrimental to the health of the patient. In these cases, there is often severe and unreconstructible damage to the neurovascular supply of the extremity or severe injuries to the skeleton, either of which may make meaningful recovery nearly impossible.
Major upper extremity amputations may also be required following burns or infections or as treatment for malignant disease. Up to 26% of electrocution injuries require some form of major amputation. Deep thermal burns result in amputations approximately 3.8% of the time, usually because of nonviable tissues, but at times for control of burn wound sepsis ( Figure 50.1 ). Most infections can be managed with antibiotics and surgical débridement, but some require amputation. For instance, invasive fungal infections such as mucormycosis almost uniformly require amputation; the mortality rate in this patient population may be as high as 92%. Advances in radiation therapy, chemotherapy, and limb salvage surgical techniques have considerably reduced the need for upper extremity amputation in sarcoma patients over the past 40 years, but radical amputation remains a mainstay of treatment for recurrent disease or large tumors.
Wrist Disarticulation and Transradial Amputation
After decades of research, the optimal level of amputation for patients who require removal of the hand remains controversial. Wrist disarticulation preserves limb length, providing an arm with a longer lever for prosthetic control. In addition, the longer residual limb preserves the distal radioulnar joint, resulting in better pronation and supination. The metaphyseal flare of the distal radius also provides a contour that aids in suspension of a terminal device ( Figure 50.2 ). However, the benefits of a wrist disarticulation come at a cost. The prominence of the styloids of the distal radius and ulna can become pressure points, leading to breakdown of the residual limb within the socket. The additional residual limb length in a wrist disarticulation also can create limb-length discrepancies when a prosthesis is worn. In fact, a myoelectric terminal device may add several centimeters to the length of the residual limb, accentuating the limb-length discrepancy seen in patients who have undergone wrist disarticulation. This not only presents an aesthetic concern but also makes it more difficult for a patient to reach the anatomic midline because greater shoulder abduction and scapular retraction are required to do so. For these reasons, patients with wrist disarticulations are more likely to abandon their prostheses than transradial amputees. Ideally, the patient is afforded the opportunity to have a preoperative consultation with a physiatrist and a prosthetist so that he or she may make an educated choice between a wrist disarticulation and a transradial amputation. Given the usual indications, however, this is unfortunately rarely the case. Amputation 8 to 10 cm proximal to the ulnar styloid provides the greatest variety of prosthetic options for functional restoration of the extremity. This preserves adequate pronation and supination and a reasonable lever arm for prosthetic control during flexion of the elbow. One form of amputation is not ideal for all patients, however, making the preoperative consultation critically important in the process. Patients who perform heavy labor frequently prefer a wrist disarticulation owing to the increased durability of a body-powered prosthetic, the increased lever arm length, and the preserved distal radioulnar joint.
As the transradial amputation becomes more proximal and approaches the elbow, the anticipated pronation and supination decrease. In fact, there is minimal pronation and supination once half of the initial forearm length is removed. Yet, preserving at least 5 cm of the ulna is sufficient for successful prosthetic fitting. Once the level of amputation moves proximally above the elbow, the dramatic increase in the amount of work required to function with the prosthesis greatly increases the likelihood of abandonment. Preserving the elbow joint should remain a high priority, even when complex reconstructive efforts such as free flaps are required to maintain this articulation.
Authors’ Preferred Method of Treatment: Transradial Amputation
The skin incisions are designed with equal-length flaps along the volar and dorsal aspects of the forearm, in what is often referred to as a fish-mouth pattern. The incisions are designed so that the osteotomies in the radius and ulna will lie at least 1 to 2 cm proximal to the level of the skin incision ( Figure 50.3 ). The arm is exsanguinated, and tourniquet control is used for hemostasis. The skin and subcutaneous tissues are elevated off of the underlying antebrachial fascia proximally past the level of the proposed osteotomies. The antebrachial fascia is incised at the level of the skin incision, and all of the neurovascular structures are individually identified. The radial and ulnar arteries are ligated with suture ties or vascular clips, and the interosseous vessels are cauterized. The nerves are dissected proximally and divided to ensure that they are positioned proximal to the level of the osteotomy. The flexor and extensor musculature is divided 1 cm distal to the level of the osteotomy. The periosteum is incised and a small cuff is elevated proximally. An oscillating saw is used to make the bony cuts, and edges are smoothed with a rasp. A myodesis is performed, first with the deeper muscle bellies fixed firmly to the underlying skeleton to establish durable bony coverage and to prevent bursitis from excessive excursion. The superficial musculature is then sutured in agonist/antagonist pairing over the end of the osteotomies to complete the myodesis. Care is taken to re-create physiologic tension to superficial muscle units to maximize postoperative contractions. The force of these contractions may ultimately be used to provide efferent motor control of a myoelectric prosthesis. The wound is closed in layers, and a bulky compressive dressing is applied.
Elbow Disarticulation and Transhumeral Amputation
Loss of the elbow joint has a significant adverse functional impact on the residual limb and greatly diminishes a patient’s adaptation to meaningful use of a prosthesis. In these more proximal amputations, the elbow must be replaced with a prosthetic component, which adds a substantial amount of weight and limits the utility of these devices. In addition, with above-the-elbow prostheses, more energy is required to perform daily functions, and thus, transhumeral amputees are more likely to abandon their prosthetics than their transradial counterparts.
The discussion regarding elbow disarticulation versus transhumeral amputation is similar to the previous discussion regarding wrist disarticulation versus transradial amputation. There are advocates for both surgical approaches because each has its benefits and drawbacks. Preservation of the distal humerus conserves the flare of the condyles, which not only aid in the suspension of the device but also allow for transmission of rotation. These benefits come at a fairly high price, however. When an elbow disarticulation is performed, the greater length of the residual upper arm creates a limb-length discrepancy, which is particularly problematic when a patient uses a prosthetic device with an elbow articulation. In these situations, it is more difficult for the patient to reach the anatomic midline, and the asymmetry with the unaffected arm is fairly noticeable, unaesthetic, and functionally limiting.
Authors’ Preferred Method of Treatment: Transhumeral Amputation
It is our preference to perform a transhumeral amputation rather than an elbow disarticulation because the benefits of the latter seem fairly minor. The exception is in the pediatric patient, where there is a high incidence of bony overgrowth following transhumeral amputation through the metaphysis, which ultimately may require surgical revision. A sterile tourniquet is used to limit blood loss and facilitate identification of key structures in a bloodless field. After exsanguination, anterior and posterior flaps are designed 2 cm distal from the level of the planned osteotomy. Ideally, the osteotomy is planned 10 cm proximal to the olecranon tip to maximize prosthetic options. The brachial artery is securely ligated with a suture ligature, and the radial, median, and ulnar nerves are dissected proximally and divided to ensure that they are positioned proximal to the level of the osteotomy. The osteotomy is performed with an oscillating saw, and any bony edges are carefully rasped so they are smooth. The tourniquet is removed and hemostasis ensured. It is possible to perform an angulation osteotomy of the distal humerus to provide rotational control of the prosthesis. This operation would only be performed, however, if there were extensive preoperative discussions with the physiatrist and prosthetist and it was determined that this would provide the optimal functional rehabilitation for the patient. This is not done routinely in all patients because it can create a pressure point in the residual limb. If it is planned, the amputation is performed more distally to account for the limb length lost with the angulation osteotomy. A myodesis is performed by securing the musculature from the anterior compartment to the posterior compartment to cover the distal humeral edge. Unlike in transradial amputations, a closed suction drain is placed to avoid fluid collections. The skin is closed in layers, and a bulky compressive dressing is applied ( Figure 50.4 ).
Interscapulothoracic Amputation
Interscapulothoracic (forequarter) amputation is the most radical and, luckily, least frequent amputation in surgical practice. This disfiguring procedure requires disarticulation of the entire shoulder girdle from the thoracic cavity. Although initially described in the setting of trauma in 1808, the surgical technique has not evolved much over two centuries because of the rarity of the procedure. Its main clinical role today is as a last resort in the treatment of aggressive malignant disease. The use of forequarter amputation has continued to decline from 32% in the 1970s to 5% in a current series because of advances in radiation therapy, chemotherapy, and limb salvage surgical techniques. Because most of these amputations are done for aggressive malignant conditions, the outcomes are generally poor. Over a 12-year span at a major orthopedic oncology center, the overall survival rate at 1 year was 42% and by 2 years, it was less than 20%.
Planning the closure of the eventual defect is important because the amputation cannot proceed any more proximally if there is tension on the skin ( Figure 50.5 ). This is particularly true in cases of recurrent sarcoma, where radiation damage to the surrounding tissues may present a dilemma and create additional challenges for soft tissue coverage. If the area of skin resection or previous irradiation will likely result in too much tension at the suture line, the surgeon should plan to fillet the forearm and use it as a fasciocutaneous free flap based on the brachial artery.
Authors’ Preferred Method of Treatment: Forequarter Amputation
The patient is placed in the lateral decubitus position, with all pressure points appropriately padded. Like most amputations, previous scars or recurrent malignant disease may affect the ultimate incision design. The classic design is an ellipse at the base of the shoulder and around the scapula, with a cephalad extension along the clavicle up to the sternocleidomastoid muscle to obtain proximal control of the subclavian vessels ( Figure 50.6 ). The anterior portion of the incision is an extension of the deltopectoral groove inferiorly, and the posterior portion crosses the acromion and runs along the medial border of the protracted scapula. The natural skin redundancy over the retracted scapula is preserved to facilitate tension-free closure.
The operation is started anteriorly, exposing the entire clavicle by releasing the muscular attachments with electrocautery. An osteotomy is completed just lateral to the origin of the sternocleidomastoid with a Cobb elevator protecting the underlying vascular structures. The osteotomy provides excellent exposure of the subclavian artery and vein, which are divided and suture ligated. If a free flap is planned for coverage, vascular control is maintained with a combination of vessel loops and atraumatic vessel clamps to preserve the vasculature for microvascular transfer. Once control of the major vessels is obtained, the pectoralis major tendon is divided and retracted medially. The origins of the coracobrachialis and short head of the biceps are dissected off of the coracoid along with the insertion of the pectoralis minor. The transverse cervical and suprascapular arteries are ligated as they cross the surgical field. If the patient is younger than 50 years of age, the major branches of the brachial plexus should be cut and implanted into the pectoralis major and serratus anterior to allow for the possibility of targeted muscle reinnervation for prosthetic control (see Frontiers in Prosthetic Rehabilitation ).
Attention is then directed posteriorly, where the incision is made along the medial border of the scapula, dissecting toward the muscular insertion of the rhomboids. As the muscle fascia is incised, the shoulder is flexed and adducted to bring the scapula off of the thorax. If one does not have sufficient help in the operating room, a hydraulic arm holder can be of great assistance. All of the muscular attachments are released superiorly and medially off of the scapula, leaving only the serratus anterior and latissimus dorsi muscles as attachments to the specimen. These tendons are divided, and the specimen is passed off for pathologic study. The skin is closed in a layered fashion over drains.
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