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Amputations of the Hand
Acute fingertip and thumb injuries are common and require prompt and meticulous composite soft-tissue repair in incomplete amputations. Complete amputations proximal to the eponychial fold in the thumb or multiple digits may be salvaged by microvascular techniques (see Chapter 63 ); however, more distal devascularizing injuries rarely can be salvaged by such means and usually require special composite soft-tissue coverage techniques or complete amputation.
In general, every effort should be made to maintain or provide good skin sensation, joint mobility, and digital length with well-padded bony elements. Prolonged efforts to preserve severely damaged structures, especially those that are insensate, can delay healing, increase disability, and lead to a painful series of surgical procedures that may not enhance the final outcome. Thus primary amputation may be the procedure of choice in many patients. Achieving supple soft-tissue coverage of the ends of the thumb and fingers is essential. In amputations of several digits, pinch and grasp are the chief functions to be preserved. Revision amputation through the fingers or metacarpals is a reconstructive procedure to preserve as much function as possible in injured and uninjured parts of the hand.
Considerations for Amputation
Amputations may be considered for a variety of conditions in which function is limited by pain, stiffness, insensibility, and cosmetic issues. A request for amputation of an injured part by a patient is usually the culmination of a critical thought process and is usually justified. More often, other factors must be considered in deciding whether amputation is advisable. The ultimate function of the part should be good enough to warrant salvage.
An analysis of the five tissue areas—skin, tendon, nerve, bone, and joint—is sometimes helpful in making the decision to amputate. If three or more of these five areas require special procedures, such as grafting of skin, suture of tendon or nerve, bony fixation, or closure of the joint, amputation should be considered because the function of the remaining fingers may be compromised by survival of a mutilated finger. In children, amputation rarely is indicated unless the part is nonviable and cannot be made viable by microvascular techniques. Principles of replantation are discussed in Chapter 63 .
Even if amputation is indicated, it may be wise to delay it if parts of the finger may be useful later in a reconstructive procedure. Skin from an otherwise useless digit can be used as a free graft. Skin and deeper soft structures can be useful as a filleted graft (see Chapter 65 ); if desired, the bone can be removed primarily and the remaining flap suitably fashioned during a second procedure. Skin well supported by one or more neurovascular bundles but not by bone can be saved and used as a vascular or neurovascular island graft (see Chapter 68). Segments of nerves can be useful as autogenous grafts. A musculotendinous unit, especially a flexor digitorum sublimis or an extensor indicis proprius, can be saved for transfer to improve function in a surviving digit (e.g., to improve adductor power of the thumb when the third metacarpal shaft has been destroyed or to improve abduction when the recurrent branch of the median nerve is nonfunctional). Tendons of the flexor digitorum sublimis of the fifth finger, the extensor digiti quinti, and the extensor indicis proprius can be useful as free grafts. Bones can be used as peg grafts or for filling osseous defects. Under certain circumstances, even joints can be useful. Every effort should be made to salvage the thumb ( Fig. 19.1 ).
Principles of Finger Amputations
Whether an amputation is done primarily or secondarily, certain principles must be observed to obtain a painless and useful stump. The volar skin flap should be long enough to cover the volar surface and tip of the osseous structures and preferably to join the dorsal flap without tension. The ends of the digital nerves should be dissected carefully from the volar flap, gently placed under tension so as not to rupture more proximal axons, and resected at least 6 mm proximal to the end of the soft-tissue flap. Neuromas are inevitable, but they should be allowed to develop only in padded areas where they are less likely to be painful. When scarring or a skin defect makes the fashioning of a classic flap impossible, a flap of a different shape can be improvised, but the end of the bone must be padded well. Flexor and extensor tendons should be drawn distally, divided, and allowed to retract proximally. When an amputation is through a joint, the flares of the osseous condyles should be contoured to avoid clubbing of the stump. Before the wound is closed, the tourniquet should be released and vessels cauterized to control bleeding.
Fingertip Amputations
Fingertip amputations vary markedly depending on the amount and configuration of skin lost, the depth of the soft-tissue defect, and whether the phalanx has been exposed or even partially amputated ( Fig. 19.2 ). In the United States, replantation is not performed for most fingertip amputations. Proper treatment is determined by the injury type and whether other digits also have been injured.
Injuries with loss of skin alone can heal by secondary intention or can be covered by a skin graft ( Fig. 19.3 ). Despite continuous descriptions of new finger flaps, healing by secondary intention can in most cases provide equivalent preservation of sensation and function. In general, revision amputation or conservative measures, such as healing by secondary intention, may have improved restoration of static two-point discrimination when compared to other coverage methods. Some studies also suggest improved overall total arc of motion with conservative methods; however, a higher incidence of cold intolerance should be taken into consideration. When tendon, nerve, or bone is exposed, soft-tissue coverage may be achieved in numerous ways. If half of the nail is unsupported by the remaining distal phalanx, a nail bed ablation usually is indicated; otherwise, a hook nail may develop. Reamputation of the finger at a more proximal level can provide ample skin and other soft tissues for closure but requires shortening the finger. If other parts of the hand are severely injured or if the entire hand would be endangered by keeping a finger in one position for a long time, amputation may be indicated. This is especially true for patients with arthritis or for patients with a less physically demanding lifestyle. A free skin graft can be used for coverage, but normal sensibility is rarely restored. A split-thickness graft is often sufficient if the bone is only slightly exposed and its end is nibbled off beneath the fat. Such a graft contracts during healing and eventually becomes about half its original size. Sometimes a full-thickness graft is available from other injured parts of the hand, but the fat should be removed from its deep surface. Occasionally, the amputated part of the fingertip is recovered and replaced as a free graft or cap technique ( Fig. 19.4 ). This procedure requires removing bone debris and partially defatting the distal part before reattachment. The cap procedure is quite successful in both children and adults. These free composite grafts should be secured by a stent dressing tied over the end of the finger.
The medial aspect of the arm just distal to the axilla, elbow flexion crease, volar forearm and wrist, and hypothenar eminence are convenient areas from which skin grafts can be obtained.
If deeper tissues and skin must be replaced to cover exposed tendon and bone, various flaps or grafts can be used. Frequently used distal advancement flaps include the Kutler double lateral V-Y and Atasoy volar V-Y advancement flaps ( Figs. 19.5 to 19.7 ). These flaps involve tissue advancement from the injured finger and provide limited coverage. The dorsal pedicle flap is useful when a finger has been amputated proximal to the nail bed ( Fig. 19.8 ). If further shortening is unacceptable, however, this type of flap can be raised from the dorsum of the injured finger and carried distally without involving another digit. Dorsal defects may be managed by adipofascial turnover flaps in which the proximal subdermal adipofascial tissues are flipped distally over a vascularized zone of the same tissue ( Fig. 19.9 ). Advantages of same-digit coverage techniques include no need for a second operation for flap division (as with a cross-finger flap), prevention of adjacent finger stiffness that occurs with adjacent finger coverage techniques (especially in patients with underlying arthritic conditions), and the opportunity for coverage in patients in whom adjacent fingers are injured. The cross-finger flap provides excellent coverage but may be followed by stiffness not only of the involved finger but also of the donor finger. This type of coverage requires operation in two stages and a split-thickness graft to cover the donor site. The thenar flap also requires operation in two stages. It usually does not cover as large a defect as a cross-finger flap and sometimes is followed by tenderness of the donor site. It does have the advantage, however, of involving only one finger directly. Thenar flaps also have been shown to be a safe and reliable option in the pediatric population. An alternative to this method is the palmar pocket method in which the distal fingertip (except that of the thumb) can be buried in the ipsilateral palm. The finger is removed from the pocket 16 to 20 days after surgery. Results were successful in 13 of 16 patients according to Arata et al. In children, we have observed that merely resuturing the defatted fingertips back in place usually results in a satisfactory result.
A local neurovascular island pedicle flap can be advanced distally and provides a good pad with normal sensibility. Flaps of 2 × 1.5 cm 2 and advancement of 18 mm have been reported ( Fig. 19.10 ). Retrograde island pedicle flaps require tedious dissection but offer excellent distal coverage and utility for dorsal and volar defects ( Fig. 19.11 ). Donor site morbidity may be reduced in retrograde island pedicle flaps that use the subdermal elements only ( Fig. 19.12 ). Comparative studies have shown no significant differences between the two flaps at 12 months.
Composite soft-tissue transfer to the small finger may be accomplished by use of an ulnar hypothenar flap. This retrograde flow flap is based on the ulnar digital artery and may be used to supply sensation when the dorsal sensory branch of the ulnar nerve is included in the skin flap ( Fig. 19.13 ). Eponychial flaps have historically been used to improve overall functional and cosmetic outcomes of distal amputations ( Fig. 19.14 ).
Despite the variability of coverage options, patient-reported outcomes demonstrate satisfactory or good-to-excellent results independent of treatment type, with minimal influence on ability to perform activities of daily living or in quality of life.
Free Skin Graft
The techniques for applying free skin grafts are described in Chapter 65 .
Flaps for Fingertip Coverage
Kutler V-Y or Atasoy Triangular Advancement Flaps
Kutler double lateral V-Y or Atasoy volar V-Y advancement flap fingertip coverage is appealing because it involves just the injured finger. It provides only limited coverage, however, and does not result consistently in normal sensibility. The injury pattern determines which flap to use. When more of the pulp skin remains, then the Atasoy flap is useful. When the pulp is compromised and the lateral hyponychial skin is uninjured, the Kutler flap can be used.
Technique 19.1
(KUTLER; FISHER)
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Local anesthesia is preferred in adults; children may require general anesthesia. Anesthetize the finger by digital block at the proximal phalanx and apply a digital tourniquet.
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Debride the tip of the finger of uneven edges of soft tissue and any protruding bone ( Fig. 19.5 ).
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Develop two triangular flaps, one on each side of the finger with the apex of each directed proximally and centered in the midlateral line of the digit. Avoid making the flaps too large; their sides should each measure about 6 mm, and their bases should measure about the same or slightly less.
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Develop the flaps farther by incising deeper toward the nail bed and volar pulp. Take care not to pinch the flaps with thumb forceps or hemostats. Rather, insert a skin hook near the base of each and apply slight traction in a distal direction. With a pair of small scissors and at each apex, divide the pulp just enough (usually not more than half its thickness) to allow the flaps to be mobilized toward the tip of the finger. Avoid dividing any pulp distally.
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Round off the sharp corners of the remaining part of the distal phalanx and reshape its end to conform with the normal tuft.
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Approximate the bases of the flaps and stitch them together with small interrupted nonabsorbable sutures; stitch the dorsal sides of the flaps to the remaining nail or nail bed.
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Frequently, closure of the proximal and lateral defects is impossible without placing significant tension on the flaps. In such instances, the sides of the triangular flaps should be left without sutures and heal satisfactorily by secondary intention ( Fig. 19.7D ). Apply Xeroform gauze and a protective dressing.
Atasoy Triangular Advancement Flaps
Technique 19.2
(ATASOY ET AL.)
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Under tourniquet control and using an appropriate anesthetic, cut a distally based triangle through the pulp skin only, with the base of the triangle equal in width to the cut edge of the nail ( Fig. 19.6 ).
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Develop a full-thickness flap with nerves and blood supply preserved. Carefully separate the fibrofatty subcutaneous tissue from the periosteum and flexor tendon sheath using sharp dissection.
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Selectively cut the vertical septa that hold the flap in place and advance the flap distally.
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Suture the skin flap to the sterile matrix or nail. The volar defect from the advancement can be left open and left to heal by secondary intention if closure compromises vascularity. A few millimeters of the phalanx can be removed to the level of the sterile matrix. The base of the flap may be difficult to suture to the sterile matrix or nail, and a 22-gauge needle can be used as an intramedullary pin in the distal phalanx to keep the flap in position.
Bipedicle Dorsal Flaps
A bipedicle dorsal flap is useful when a finger has been amputated proximal to its nail bed and when preserving all its remaining length is essential, but attaching it to another finger is undesirable. When this flap can be made wide enough in relation to its length, one of its pedicles can be divided, leaving it attached only at one side ( Fig. 19.8 ).
Technique 19.3
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Beginning distally at the raw margin of the skin and proceeding proximally, elevate the skin and subcutaneous tissue from the dorsum of the finger.
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At a more proximal level, make a transverse dorsal incision to create a bipedicle flap long enough, when drawn distally, to cover the bone and other tissues on the end of the stump.
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Suture the flap in place and cover the defect created on the dorsum of the finger by a split-thickness skin graft. The flap can be made more mobile by freeing one of its pedicles, but this decreases its vascularity.
Adipofascial Turnover Flap
The adipofascial turnover flap is a de-epithelialized flap that may be used to cover distal dorsal defects 3 cm in length.
Technique 19.4
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Under tourniquet control, repair the traumatic defects as indicated, such as extensor tendon repair and fracture fixation.
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Outline the planned flap with a skin pen. Make the width 2 to 4 mm wider than the traumatic defect. The base-to-length ratio should be 1:1.5 to 1:3. The flap base should be 0.5 to 1 cm in length and is made just proximal to the defect. The flap length should be at least this much longer than the defect ( Fig. 19.9B ).
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Develop the adipofascial flap superficial to the extensor tendon paratenon from proximal to distal ( Fig. 19.9C ).
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After the flap is detached proximally and along its sides to the flap base, flip it over and suture it distally ( Fig. 19.9D ).
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Do not place sutures at the turnover site to avoid tension on the vascular pedicle ( Fig. 19.9E ).
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Use a split-thickness graft to cover the defect at the flap site.
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Immobilize the digit in a protective splint.
Postoperative Care
The first dressing change is 3 weeks after surgery, and digital motion is begun as wound healing and other concomitant injuries allow.
Cross-Finger Flaps for Reconstruction of Fingertip Amputations
The technique of applying cross-finger flaps is described in Chapter 65 .
Thenar Flap
Middle and ring finger coverage can be accomplished by the use of the thenar flap. Donor site tenderness and proximal interphalangeal joint flexion contractures can occur, and the flaps should not be left in place for more than 3 weeks.
Technique 19.5
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With the thumb held in abduction, flex the injured finger so that its tip touches the middle of the thenar eminence. Outline on the thenar eminence a flap that when raised is large enough to cover the defect and is properly positioned; pressing the bloody stump of the injured finger against the thenar skin outlines by bloodstain the size of the defect to be covered ( Fig. 19.15A,B ).
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With its base proximal, raise the thenar flap to include most of the underlying fat; handle the flap with skin hooks to avoid crushing it even with small forceps. Make the flap sufficiently wide so that when sutured to the convex fingertip it is not under tension. Make its length no more than twice its width. By gentle undermining of the skin border at the donor site, the defect can be closed directly without resorting to a graft.
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Attach the distal end of the flap to the trimmed edge of the nail by sutures passed through the nail. The lateral edges of the flap should fit the margins of the defect, but to avoid impairing circulation in the flap, suture only their most distal parts, if any, to the finger. Prevent the flap from folding back on itself and strangulating its vessels ( Fig. 19.15C and D ).
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Control all bleeding, check the positions of the flap and finger, and apply wet cotton gently compressed to follow the contours of the graft and the fingertip.
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Hold the finger in the proper position by gauze and adhesive tape and splint the wrist.
Postoperative Care
At 4 days, the graft is dressed again and then kept as dry as possible by dressing it every 1 or 2 days and by leaving it partially exposed. At 2 weeks, the base of the flap is detached and the free skin edges are sutured in place. The contours of the fingertip and the thenar eminence improve with time.
Local Neurovascular Island Flap
An antegrade neurovascular island graft can provide satisfactory padding and normal sensibility to the most important working surface of the digit.
Technique 19.6
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Make a midlateral incision on each side of the finger (or thumb) beginning distally at the defect and extending proximally to the level of the proximal interphalangeal joint or thumb interphalangeal joint.
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On each side and beginning proximally, carefully dissect the neurovascular bundle distally to the level selected for the proximal margin of the graft ( Fig. 19.16A ). Here make a transverse volar incision through the skin and subcutaneous tissues, but carefully protect the neurovascular bundles ( Fig. 19.16B ).
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If necessary, make another transverse incision at the margin of the defect, freeing a rectangular island of the skin and underlying fat to which the two neurovascular bundles are attached.
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Carefully draw this island or graft distally and place it over the defect ( Fig. 19.16C ). Avoid placing too much tension on the bundles. Should tension compromise the circulation in the graft, dissect the bundles more proximally or flex the distal interphalangeal joint, or both.
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Suture the graft in place with interrupted small nonabsorbable sutures.
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Cover the defect created on the volar surface of the finger with a free full-thickness graft.
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Carefully place contoured sterile dressings such as glycerin-soaked cotton balls over the grafts to lessen the likelihood of excess pressure on the neurovascular bundles.
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Apply a compression dressing until suture removal at 10 to 14 days.
Postoperative Care
Begin digital motion therapy as soon as the wounds permit.
Island Pedicle Flap
The axial-pattern island pedicle flap may be used to provide sensation or merely composite soft tissue to adjacent fingers or thumb. The skin paddle size can vary to suit the defect.
Technique 19.7
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This procedure is performed as outpatient surgery, and general anesthesia is preferred.
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Inflate the arm tourniquet after using a skin pen to outline clearly the intended flap design.
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Measure the defect size after appropriate debridement and draw a slightly larger flap onto the donor digit.
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Use a midaxial or a volar zigzag incision to expose the neurovascular bundle of the area of the superficial arch, the usual pivot point of the flap.
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If a neurovascular island flap is desired to provide sensation to a given area, it is imperative that the ulnar border of the small finger and radial border of the index finger not be used as donors because maintaining or achieving sensation in these areas is desirable. The skin paddle is ideally centered over the neurovascular bundle.
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Under tourniquet control, locate the neurovascular bundle proximally and carefully dissect this to its superficial arch origin. Leave a cuff of soft tissue around the neurovascular bundle because discrete veins are not readily visible but exist in the periarterial tissues. Dissect the bundle deeply and use bipolar cautery well away from the proper digital artery to control perforating vessels entering the flexor sheath.
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Elevate the skin paddle, taking care to ensure the vascular bundle is reasonably centered under the flap, and divide the artery distally.
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Use a simple 5-0 nylon suture to secure the distal vascular bundle to the distal edge of the skin flap.
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Place the paddle over the recipient site to determine the best path for the pedicle because the pedicle should not be under any tension. The skin between the pivot point can be undermined and enlarged by gently yet liberally spreading a hemostat in the intended pedicle path. The tunnel must allow easy passage of the flap. Frequently, a 2 to 3 cm skin bridge can be left between the proximal donor and recipient incisions. However, if any doubt remains in regard to the pedicle tension or impingement, these incisions should be connected.
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Deflate the tourniquet and control bleeding.
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Draw the 5-0 nylon suture gently through the skin bridge, taking care not to place shear stress between the pedicle and flap.
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Suture the flap loosely into position and close the remaining wounds. Ensure the flap remains well vascularized before placing a loose dressing and protective splint.
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Note: When this procedure is performed as a vascular island pedicle flap, the proper digital nerve should be carefully preserved and protected to prevent problematic neuromas. Transient dysesthesias that commonly occur with this technique usually resolve in 6 to 8 weeks.
Postoperative Care
The patient is seen in 5 to 7 days, and motion therapy is begun as soon as the wounds permit, usually 2 to 3 weeks postoperatively.
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