Acute Hand Injuries

Splinting

When splinting is necessary, it is important to remember that improper technique should be avoided, as it can lead to joint stiffness, skin breakdown, or worsening deformity. A splint should be used to relax muscles, maintain correct position, and immobilize the hand in a position that will prevent further injury. Immobilization should be above and below the injury or deformity but not farther, allowing function to the unaffected parts ( Fig. 65.2 ) (see Chapter 64 ).

Anesthesia

A digital block, regional block, or general anesthetic may be selected, depending on the patient’s age and general condition, the severity of the injury, other injuries, the interval since the last ingestion of food or drink, and whether or not a distant flap will be necessary (see Chapter 64 for more details). Some surgeons have expanded the indications for the wide-awake local anesthesia with no tourniquet (WALANT) technique to acute surgery of the hand (see Chapter 64 ).

Tourniquet

A tourniquet is necessary while the wound is being cleansed and inspected and while the deep structures are being repaired. When the viability of an area of skin is questionable because of a crushing or avulsing injury, a tourniquet should be used as briefly as possible. For a large wound with fractures, elevation of the hand for 2 minutes is better than wrapping it with an elastic (Martin) bandage before inflation of the tourniquet. This prevents further crushing and displacement of fracture fragments (for more information on the tourniquet, see Chapter 64 ).

Cleansing and Draping of Hand

After the patient or the part is anesthetized and the tourniquet is applied, the first aid dressing is removed and the wound is thoroughly irrigated with normal saline solution, generally through a pulsating lavage apparatus to provide a stream with enough force to loosen small foreign particles and to remove large hematomas. Antiseptics generally are not used in the wound because of potential tissue toxicity. Small bleeding vessels, which sometimes are more easily seen under saline solution, are clamped with mosquito hemostats and cauterized. Small flaps and tags of devitalized fat and fascia seen floating in the solution can be removed at their bases. Nerve ends are not debrided. Ragged skin edges may be trimmed, but complete excision of the edges of the wound usually is unnecessary in the hand.

As the deeper parts of the wound are cleaned, they are carefully searched for foreign materials, especially if there is suspicion that they contain broken glass, wood, or pieces of glove or when the wound has been caused by a gunshot. Cleaning should not be hurried; it must be thorough to help prevent infection. Primary healing without infection is necessary to limit the scar and to allow additional early reconstruction, if needed. When cleaning is complete, all instruments, gloves, and drapes used during this process are discarded and the hand is redraped (see Chapter 64 for the details of draping and of the routine in the operating room).

After a diligent effort has been made to convert the contaminated wound into a clean one in the operating room, the wound is reexamined. The circulatory status of the skin is assessed with the usual observations of color and capillary refill in the digit and bleeding of the skin after needle or scalpel puncture and with a Doppler probe for the larger vessels in the hand and upper extremity.

The tissues in the depths of the wound, including exposed bones, tendons, vessels, and nerves, are assessed in an orderly, anatomic manner to avoid error; the skin also is examined carefully. Only after an accurate assessment of the damage can correct decisions be made as to which structures can be repaired primarily. Bones and joints are inspected to assess bone loss, the extent of periosteal stripping, and fracture stability. This evaluation allows estimation of potential bone healing and the advisability of early joint motion after internal fixation of fractures. Conclusions drawn from the first examination may be wrong, so suspected tendon and nerve injury should be confirmed by direct inspection. Usually, the damage has been underestimated.

Evaluating the skin damage is most important because primary wound closure depends on skin viability. Frequently, some skin appears to be lost when actually it has only retracted; this is especially true of L-shaped wounds on the dorsum of the hand. When skin is crushed or flaps of skin are avulsed, the possibility of necrosis must be seriously considered. Releasing the tourniquet may be necessary for accurate evaluation. A valuable sign that skin is viable is a prompt pink blush (about 6 seconds) after release of the tourniquet. The extent of bleeding from the skin edges, the color of the skin immediately after compression, and the amount of undermining of the skin edges must be observed. Necrosis, infection, and scarring can occur if flaps of doubtful viability are retained. The extent of skin loss from the injury itself and after surgical excision of nonviable flaps must be evaluated, and plans must be made for complete coverage. Passive finger motion often delivers severed tendons into the wound. Small hematomas seen within synovial sheaths may be indications of further tendon injury.

Direct Suture

Unless the wound is severely contaminated or crushed, consideration should be given to primary closure of every wound of the hand (except those mentioned previously) because healing by primary intention is the desired result. Treatment of some lacerations without suturing may be satisfactory in certain patients. Most clean lacerations without tendon or nerve involvement can be closed by simple direct suture of the skin and splinted. Usually the subcutaneous tissue is not sutured separately, but care should be taken to avoid inversion of the skin edges. Careful hemostasis is necessary. Closure is easier when all viable skin edges have been preserved during the initial cleansing. A skin defect on the dorsal surface of the hand can be converted to a transverse elliptical one and closed in a transverse line. Because of the mobility of the dorsal hand skin, this type of closure is possible here and is made easier when the wrist is extended.

Because sutures are by definition “foreign bodies,” they may generate an inflammatory response, interfere with wound healing, and increase the risk of infection; the number and diameter of sutures used for wound closure should be kept to the minimum necessary.

Skin Grafts

Skin grafts obtained from the patient (autografts) are either split thickness or full thickness. Wounds with distally attached flaps may have enough skin for primary closure but not enough venous drainage for the skin to survive. This deficient drainage causes engorgement and venous distention and finally thrombosis and necrosis; the color of the flap changes from a deep blue to purple and then to black. The retrograde flap is often the result of a crushing or tearing injury, and the nature of this injury jeopardizes the survival of the flap further. Such a flap on the dorsal surface of the hand or forearm is less likely to survive than one on the palm ( Fig. 65.3 ). If doubt exists, the skin should be excised and replaced with a split graft (see Technique 65.1).

If skin is lost and no deep structures (nerves, tendons, joints, or cortical bone) have been exposed, it should be replaced immediately with a split-thickness graft or occasionally with a full-thickness graft. Other types of skin grafts that may have applications in the injured hand include allografts from other human donors and xenografts from other species (e.g., porcine skin). Both are used for temporary coverage while a capillary bed develops. Although an allograft may revascularize, rejection occurs, and it is replaced with an autograft.

Skin Flaps

When a skin defect leaves deep structures exposed, a split-thickness or full-thickness skin graft is insufficient coverage for nerves, tendons, and cortical bone. These structures do not readily support a skin graft and require good blood supply to survive. A skin flap is necessary to provide subcutaneous tissue for coverage and for sufficient vascularity. The nomenclature of flaps depends on the location, blood supply, and technique of transfer. By location, a flap may be termed local or distant. The blood supply determines whether the flap is random or axial. Random flaps receive their circulation through the subdermal or subcutaneous plexus of vessels and do not have a named artery supplying them. Axial pattern flaps receive their circulation from a named artery. Axial flaps also are subdivided by the major tissue of the flap into cutaneous, musculocutaneous, and fasciocutaneous flaps. The technique of transfer of a flap determines whether it is a pedicled flap to be transferred in two stages or a free flap, which is transferred in a single step, with vascular anastomoses.

Coverage of Specific Areas with Flaps

Fingertip injuries with only skin loss less than 1 cm square usually can be treated satisfactorily with healing by secondary intention. If the defect is larger without exposed bone, a full-thickness skin graft provides good coverage and the potential for return of some sensation. Hassanpour et al. described the use of a purse-string suture in conjunction with conventional flap coverage of 41 fingertip amputations to restore nail and finger contour and improve the aesthetic and functional results ( Fig. 65.4 ). They reported only one poor functional result; cosmetic results were excellent or good in all nine female patients and in 26 of the 32 male patients. The use of local, rotational, advancement, and neurovascular island flaps for amputations and injuries of the fingertip and thumb is discussed in Chapter 63 .

A large skin defect on the dorsum of a finger that exposes tendons not covered with paratenon should be covered with a flap. Frequently, a double local flap can be constructed by rotating a proximally based local flap on one side and a distally based local flap on the other side of the defect to cover the exposed tendon. The donor defects are covered with split grafts. For more proximal dorsal injuries, local rotational flaps from the same finger are insufficient and a reverse cross finger flap from the dorsum of an adjacent finger may be used. A “flag” flap, which is an axial flap, may be used for proximal palmar and dorsal digital defects (see Fig. 65.22 ). If multiple fingers are involved, or if a larger area needs to be covered, a subpectoral flap may be appropriate. Thick subcutaneous fat, as is found on the lower abdomen, is not preferred on a flap, especially on the finger.

Skin defects on the volar surface of a finger that expose tendons may be covered with a cross finger flap. The flap is raised from the dorsal surface of an adjacent finger and extends from the midline of one of its lateral surfaces to that of the other; the flap is a little wider than the defect it is to cover. Although such a flap from the dorsal surface of one finger can be used to cover a defect on the volar surface of another, the reverse is never indicated. Skin defects on the palm or dorsum of the hand that expose vital structures can be covered with a local flap, a flap from an adjacent unsalvageable finger, a flap from the opposite forearm or upper arm, an axial pattern flap from the same forearm or hand, a flap from the abdomen, or a free flap, depending on the size of the defect and the presence and location of any associated injuries. Although cross arm and cross forearm flaps provide good skin, immobilizing both upper extremities is a disadvantage. In suitable situations, an arterialized axial flap from the same forearm allows comfortable positioning of the upper limb. An abdominal flap from the same side also permits comfortable positioning of the arm. To ensure survival of the random pattern flap (because it must be applied immediately), its base should be as wide as its length. The length-to-width ratio may exceed 3 : 1 with axial pattern flaps such as the groin pedicle flap. The donor area and the raw part of the flap that does not make contact with the defect should be covered with split-thickness skin grafts. A local rotation flap is unlikely to survive, however, if undermining of the skin is extensive, especially if the skin is already crushed or contused from the injury. A filleted injured finger makes an excellent pedicle graft when this technique is applicable ( Fig. 65.5 ). In some situations, free tissue transfer by microvascular technique provides the best coverage (see Chapter 63 ).

More recently, the use of “artificial skin” or skin substitutes has been reported for initial coverage of severe hand wounds, burns, and contracture release procedures. Although these products are not substitutes for adequate surgical debridement and standard coverage strategies such as grafts and flaps, they may be useful in selected patients. The product most frequently reported in the hand literature is a bilayer dermal regeneration template (Integra; Integra LifeSciences Corp., Plainsboro, NJ). The dermal layer is made of bovine type I collagen, and the epidermal layer is made of silicone. Weigert et al. reported the use of Integra for management of 15 severe traumatic hand wounds with bone, joint, or tendon exposure; split-thickness grafting was done at an average of 26 days after injury. In 13 of the 15 hands, a durable, functional, and aesthetic coverage was obtained with this technique. Advantages of the skin substitutes include potentially less need for local rotational or free-flap coverage, ease of use, and immediate availability in large quantities and different sizes. Disadvantages include its high cost, the learning curve for use, and a higher risk of seroma or hematoma formation.

Management of Donor Area

Several acceptable methods are used for treating the donor area. In one, the donor area is dressed with one layer of finely woven nylon or silk gauze. If the dressing prevents drying, the donor area tends to become macerated and secondary infection and necrosis may occur; this area itself may require skin grafting later. Otherwise the part is left uncovered, and drying of the area is encouraged. In another technique, a synthetic adhesive film is placed over the donor site. Serum and blood accumulate daily for 1 to 2 days, and the film is changed. After 7 to 10 days, this can be removed and the area is left open, usually with satisfactory healing. Bed sheets should be kept off the donor site with a bed cradle support.

Free Grafts

When free skin grafts are to be obtained, remember that “the thinner the graft, the better the take”; however, when the graft is expected to be permanent, “the thicker the graft, the better the function.” A thick graft is better able to withstand friction and constant use than a thin one and contracts only about 10%; a thin graft may contract 50% to 75%. The sooner the graft can be applied, the better. As long as there is no sepsis, it is not necessary to wait for granulation to begin before skin grafting. Sepsis can be identified with swabs for culture or with wound biopsy for a quantitative colony count. For the graft to survive, it must reestablish its nutrition before death of its entire thickness occurs; great care is needed in operative technique and in aftercare to ensure that it remains undisturbed and in direct contact with the recipient area during healing. This takes careful planning, especially in children. The graft cannot survive if a hematoma separates it from the underlying vascular bed; rarely, it may survive a gross infection. For primary coverage of acute wounds, free skin grafts usually are of thin or medium thickness. They usually do not survive on bare cortical bone, bare tendon, or bare cartilage. Except for fingertip injuries, full-thickness free skin grafts are used infrequently on the hand. Such grafts or thick split grafts can be used, however, for the palmar surface because it contains elastic tissue, and in growing children these contract less and tend to accommodate growth. Because the survival of a full-thickness graft is so uncertain, it is best used only in elective surgery for skin coverage in the palm; it should be used rarely in acute injuries, with the possible exception of the fingertips.

Split-Thickness Skin Grafts

Frequently, only a small or postage stamp graft is needed, and it can be obtained within the same operative field from the forearm; however, taking a graft from this area can be undesirable because it leaves a slight scar. The hypothenar area of the palm can be used to obtain satisfactory split-thickness skin grafts, especially for skin loss on the fingertips. More suitable donor areas for these and larger grafts are the anterior and lateral aspects of the thigh and the medial aspect of the arm just inferior to the axilla. In some older women, skin is available inferior to a pendulous breast without leaving a readily visible scar. Split-thickness skin grafts vary in thickness from 0.008 inch in infants to 0.015 inch in adults. In elderly individuals and children, the lower abdominal wall or buttock skin is used if the graft is more than 0.010 inch.