Figure
1. This child was struck by a car
and sustained degloving injuries to both
legs. There were no orthopedic or
vascular injuries. Skin grafts were used
to reconstruct the defects.
The mangled extremity presents a challenge to vascular, orthopedic and plastic surgeons. Limb salvage rates have improved greatly over the past 20 years, primarily because of new techniques in soft tissue reconstruction. Although the basic principles in vascular and bony reconstruction have long been established, only during the last two decades has treatment of these severe soft tissue injuries become commonly available and reliable. With the development of microvascular free tissue transplants, many formerly lost limbs can be salvaged. Indeed, we must be prudent with our indications for limb salvage. Nearly any mangled extremity can be covered using this technique and theoretically saved. A viable yet painful, stiff or insensate limb hardly serves the patient; the instinctive desire on both the patient and physicians' part to save a limb at all costs must be tempered by the expected long-term functional result. Extremity trauma is the most costly form of moderate trauma1.
The most heroic and beautifully performed vascular and orthopedic operations are wasted without concomitant coverage of these repairs. Likewise, some extremity injuries are predominantly or solely soft tissue injuries (Figure 1). Each patient presents a unique challenge and creativity plays a large part in soft tissue reconstruction. Attempts to classify these injuries are therefore difficult at best. The Gustilo classification of open fractures is an orthopedic classification, but has been adopted by many practitioners to describe mangled limbs in general (Table 1). There are basic principles to be followed, but an algorithmic approach is not always possible. These basic principles will be presented here.
|
Figure
1. This child was struck by a car |
Table 1. Classification of Open Fractures2 |
|
| Type I. II. IIIa. IIIb. IIIc. |
Characteristics
|
Once the patient has been stabilized (17% have concomitant life threatening injuries3), attention can be directed to the injured limb. Foremost in the assessment is determining whether ischemia is present. Prolonged ischemia, i.e. greater than 6 hours, may preclude any attempts at salvage. The role of arteriography in the acute trauma setting has been argued4. We do not obtain angiography if pulses are present prior to soft tissue reconstruction. If vascular repair is required this is usually evident on examination and if necessary, on-table angiography can be performed. Fasciotomy is always indicated in the ischemic limb. The presence of open wounds or fractures does not assure adequate decompression of the muscular compartments.
Attention should then be directed to neurologic assessment. Since physical examination may be impossible if the patient is obtunded or altered in the presence of ischemia, direct exploration of the nerve may be required. There is no role for electrophysiologic nerve testing in the acute setting. High transection of a major peripheral nerve, i.e. above the elbow or the knee, is a contraindication to heroic efforts at limb salvage. Similarly, replantation of the traumatically amputated lower limb is not indicated in adults, because the resultant neurologic function after repair is so poor and the patient is better served with complete amputation (Figures 2 and 3).
 |
|
| Figure 2. After
being struck by a train, this patient sustained traumatic amputation of the left leg and open fracture and degloving of the right leg. He also had degloving of the sole of the right foot. |
Figure 3.
Reimplantation of legs in adults is rarely indicated. However the tissue may be used to treat other injuries. Here the left foot was transplanted to the right foot. The dorsalis pedis vessels of the left foot were anastomosed to the posterior tibial vessels of the right. Once viability of the tissue was confirmed, the left foot was deboned and the soft tissue used to resurface the sole of the right foot. |
The mainstay of initial wound management is debridement of all obviously dead tissue. Marginally viable tissue may be saved and re-examined the next day. Such serial debridements are often necessary if one is to preserve as much tissue as possible. Nerves, tendons and bone fragments with soft tissue attachments should be saved, as determining their viability can be difficult and as long as soft tissue coverage is provided in a timely manner, they can function as free grafts (Figures 4A and 4B.) Next, the wound must be copiously irrigated with isotonic solution, removing bacteria and foreign material. Following bony stabilization, a plan for soft tissue coverage can be developed.
 |
 |
| Figure 4A. Crush injury to the
forearm with exposed tendons. The tendons are preserved even though they have been stripped of their blood supply. |
Figure 4B (bottom). The same
patient 4 months later following bony union and soft tissue reconstruction with microvascular free tissue transfer. |
Some controversy has surrounded the question of when the wound should be closed. Exposed vital structures, such as vascular grafts, mandate coverage immediately. Some advocate coverage at the time of presentation, before the wound has been heavily colonized with bacteria5, others within 6 days6. Ideally, definitive coverage would be performed when the wound is clean, stable, and before it becomes colonized with pathogens such as pseudomonas aeruginosa.
| With a better understanding of wound physiology most acute wounds today can be successfully managed and closed (see Table 2). This spares the patient time, cost, and speeds rehabilitation, prevents sequelae of chronic wounds, obviates the development of chronic infection and may prevent scar carcinoma. Indications for mandatory wound coverage include exposed vessels, nerves, bone, tendons or prosthetic material; in other words, the situations most likely to be found in a severely injured limb (Figures 5A and 5B). It is here that newer techniques in tissue transfer have excelled. | Table
2. Soft Tissue
|
 |
 |
| Figure 5A. Severe
crush injury to the leg with 7 cm of bone loss. The smooth zone in the middle (blue in color) is methylmeth-acrylate impregnated with antibiotics. |
Figure 5B. The
same patient 3 weeks following soft tissue reconstruction with a latissmus dorsi muscle free flap. Bone grafting of the missing bone segment can now be performed as adequate soft tissue coverage has been accomplished. |
Throughout history, open wounds have been managed by allowing the wound to heal by secondary intention. This approach is still applicable today in many cases, and preferred in cases of gross infection. There are some wounds that should not be closed including abscess cavities, necrotizing infections, wounds infected with gas-forming organisms and fresh electrical and crush injuries.
Skin grafting is commonly used in these injuries either for primary wound coverage or for closure of donor sites and fasciotomy sites. It is well tolerated, easy to perform and usually successful. Unfortunately, skin graft "take" is poor or impossible on exposed bone, tendon and prostheses, and transfer of tissue with its own blood supply is necessary.
Flaps are simply layers of tissue with an intact pre-existing blood supply that are moved to cover an adjacent wound (local flaps). They may be composed of skin, muscle, bone, tendon, fascia, nerve or even entire organs, so long as they have a blood supply sufficient to keep the transferred tissue alive. Most commonly, flaps are based on discrete named vessels, an artery and accompanying vein (s). Muscle flaps are frequently used in traumatic wounds because of their excellent blood supply and their malleability (Figures 6A and 6B). They are also large enough to cover many wounds. In the extremities, local flaps have great utility in the hands, feet and proximally near the hip and shoulder. In between these areas, especially in the distal leg, there is a paucity of tissue suitable for transfer, and tissue must be transferred from a remote site.
 |
 |
Figure 6A. Gustilo IIb Injury of the leg
with
|
More properly termed free tissue transplantation, but commonly referred to as a "free flap," this technique gained widespread use in the 1980's. The technique enables the surgeon to transfer virtually any autologous tissue as long as the tissue can be isolated on a feeding artery and draining vein. The number of flaps so devised are far too numerous to list here, but include all those listed above as well as omentum, intestine, even digits. Several atlases describe the flaps and relevant vascular anatomy nicely7. The choice of flap is dictated by tissue requirements in the limb. Composite flaps of skin, muscle or fascia and bone are often used. Recipient vessels in the injured extremity, roughly approximating the flap vessels in size, are prepared under the microscope for microvascular anastomosis. It is important to avoid using vessels in the "zone of injury," as these vessels may have sustained damage to their intima and predispose the anastomosis to thrombosis. After isolating the flap, the donor vessels are divided and the tissue transplanted to the extremity. Under the operating microscope, the donor vessels are anastomosed to the recipient vessels in either an end-to-end or end-to-side fashion (Figures 7A, 7B, 7C). Because these vessels are often less than 1mm in diameter, and since the only blood supply is through these anastomoses, thrombosis will lead to flap death. Technique is critical. Most centers performing these procedures have a success rate around 95%. The indications and contraindications for free tissue transfer are listed in Table 3.
 |
 |
 |
| Figure 7A (top).
Gustilo IIIc injury of the ankle following treatment of his fracture. |
Figure 7B. A
composite free flap of skin fascia and tendon is harvested from the forearm and isolated on the radial artery and cephalic vein. |
Figure 7C.
Following free tissue transfer to the ankle. The palmaris longus tendon was used to replace the missing posterior tibialis tendon and the radial artery has been anastomosed to the severed posterior tibial artery. |
Table 3. Free Tissue Transfer |
|
Indications For Free
Tissue Transfer
|
Contraindications To Free
Tissue Transfer
|
Limb salvage rates have improved from 58% for Gustilo IIIc injuries in 19792, to 94% with the use of free tissue transfer 10 years later8. Obviously a new dimension in the treatment of severely injured limbs has been opened.
REFERENCES
May, 1998/ Jacksonville Medicine
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