Amputations of the Upper Extremity

Chapter 18 Amputations of the Upper Extremity

Amputations should be considered the start of rehabilitation. Major amputations of the upper extremity (other than digital amputations) account for 3% to 15% of all amputations and are approximately 20 times less common than amputations of the lower extremity. Trauma is the most common reason for upper extremity amputations except for shoulder disarticulation and forequarter amputations, for which malignant tumors are the primary reasons. Generally, all possible length should be preserved in upper extremity amputations. Length preservation can be maintained by careful evaluation and lengthening of a short stump by distraction osteogenesis (the method of Ilizarov) and microvascular anastomosis. Distal-free flaps and spare-part flaps (fillet flaps) from the amputated limb also should be used to preserve length. However, prosthetists are able to fit even small stumps with prostheses to improve function. Often a small stump distal to the elbow can be functionally better than a long above-elbow amputation. A prosthetic limb cannot adequately replace the sensibility of the hand, and the function of a prosthetic limb decreases with higher levels of amputation. Few patients with amputations around the shoulder are regular prosthetic users. The use of a rigid dressing and subsequent early temporary prosthetic fitting in patients with transhumeral or more distal amputations encourages the resumption of bimanual activities, softens the psychological blow of limb loss, and decreases the prosthetic rejection rate. After 4 to 6 weeks postoperatively the soft tissues have healed significantly and the edema should be controlled enough to proceed with a definitive socket for the patient. A myoelectrical prosthesis may be an option for patients with a below-elbow amputation. However, in manual workers a more traditional device should be employed. Some institutions use hybrid systems consisting of a locking shoulder joint with a body-powered elbow and externally powered wrist and terminal devices. These systems are most useful in amputations of the dominant extremity. Recipients use the prosthesis for approximately 14 hours a day. Some reports indicate, however, that 50% of patients discontinue the use of the prosthesis after 5 years. Various terminal devices are available and are easily interchanged (Fig. 18-1). Regardless, experienced prosthetists are invaluable in ensuring that patients have proper functional devices, and they should be consulted, when available, for each patient.

Wrist Amputations

Whenever feasible, transcarpal amputation or disarticulation of the wrist is definitely preferable to amputation through the forearm because, provided that the distal radioulnar joint remains normal, pronation and supination are preserved. Although only 50% of any pronation and supination is transmitted to the prosthesis, these motions are extremely valuable to the patient, and every effort should be made to preserve them. In transcarpal amputations, flexion and extension of the radiocarpal joint also should be preserved so that these motions, too, can be used prosthetically. Although difficult, prosthetic fitting of transcarpal amputation stumps can be achieved by a skilled prosthetist. Excellent wrist disarticulation prostheses are now available, and thin prosthetic wrist units can be used that eliminate to a considerable extent the previous objection of the artificial hand or prosthetic hook extending below the level of the opposite hand. Compared with more proximal amputations, the long lever arm afforded by amputation at the wrist increases the ease and power with which the prosthesis can be used.

Disarticulation of the Wrist

Technique 18-2

Forearm Amputations (Transradial)

In amputations through the forearm, as elsewhere, preserving as much length as possible is desirable. When circulation in the upper extremity is severely impaired, however, amputations through the distal third of the forearm are less likely to heal satisfactorily than those at a more proximal level because distally the skin is often thin and the subcutaneous tissue is scant. The underlying soft tissues distally consist primarily of relatively avascular structures, such as fascia and tendons. In these exceptional circumstances, an amputation at the junction of the middle and distal thirds of the forearm is preferable. In amputations through the proximal third of the forearm, even a short below-elbow stump 3.8 to 5 cm long is preferable to an amputation through or above the elbow. From a functional standpoint, preserving the patient’s own elbow joint is crucial. By using improved prosthetic fitting techniques, such as the Münster or a split socket with step-up hinges, a skilled prosthetist can provide an excellent prosthetic device for even a short below-elbow stump.

Distal Forearm (Distal Transradial) Amputation

Technique 18-3

image Beginning proximally at the intended level of bone section, fashion equal anterior and posterior skin flaps (Fig. 18-3A); make the length of each about equal to one half of the diameter of the forearm at the level of amputation. Together with the skin flaps, reflect the subcutaneous tissue and deep fascia proximally to the level of bone section.

image Clamp, doubly ligate, and divide the radial and ulnar arteries just proximal to this level.

image Identify the radial, ulnar, and median nerves; draw them gently distally; and transect them high so that they retract well proximal to the end of the stump.

image Cut across the muscle bellies transversely distal to the level of bone section, and allow their ends to retract to that level.

image Divide the radius and ulna transversely, and rasp all sharp edges from their ends (Fig. 18-3B).

image Close the deep fascia with fine absorbable sutures and the skin flaps with interrupted nonabsorbable sutures (Fig. 18-3C), and insert deep to the fascia a rubber tissue drain or, if preferable, a plastic tube for suction drainage.

image If desired, a myoplastic closure may be done in this amputation as follows. After raising appropriate flaps of skin and fascia, fashion an anterior flap of flexor digitorum sublimis muscle long enough so that its end can be carried around the end of the bones to the deep fascia dorsally.

image Divide the remaining soft tissues transversely at the level of bone section.

image After dividing the bones and contouring their ends, carry the muscle flap dorsally, and suture its end to the deep fascia over the dorsal musculature. To prevent excessive bulk, the entire anterior muscle mass should never be used in this manner.

image Close the stump as already described.

Jun 5, 2016 | Posted by in ORTHOPEDIC | Comments Off on Amputations of the Upper Extremity

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