 |
 |
 |
| Figures 1A, 1B, and 1C. Severe degloving injury of foot. The problem is that the foot remains viable and with protective sensation. Coverage completed with rectus free flap. | ||
Severe injuries require a coordinated approach to assure functional salvage and decisions regarding amputation require careful judgement. These decisions cannot and often do not have to be made upon initial presentation but the patients and their families need to be prepared for the rigorous task of salvage or ablation as the situation dictates. The process of limb salvage entails anatomic replantation as well as functional restoration and this will comprise on average of eleven months and seven surgical procedures1,2,3. Unfortunately, not every salvaged limb becomes functional to the patient's satisfaction and late amputations occur approximately 19%. Functional and social reintegration appears to be dependent on severity of the soft tissue injury for both treatment groups2.
Historically a very small population (0.5%) of patients presenting to our Trauma Center, and other centers around the country actually present with a traumatic amputation or with a lower extremity that is truly doomed.
The patients that produce the decision-making dilemma are those with significant injuries or injury to the lower extremity yet has a viable foot (Figure 1A-1C), and the prognosis for a functional limb is so poor that primary amputation is indicated, but oftentimes not performed during their primary hospitalization.
|
|
|
| Figures 1A, 1B, and 1C. Severe degloving injury of foot. The problem is that the foot remains viable and with protective sensation. Coverage completed with rectus free flap. | ||
The purpose of this article is to extol the technical attributes and methodology to successful limb salvage. However, the topic would not be adequately covered without a clear understanding that limb salvage is not for everyone with a mangled extremity8. The physiologic toll that the body takes while undergoing limb salvage is enormous, not to mention the psychological and financial burden that accompanies the process of useful limb salvage7. Limb salvage patients will have longer hospitalizations, more complications and greater long-term disability. Data still support the aggressive limb salvage treatment for the younger patients, as total societal costs are less over the working lifetime of the individual2.
Even today the majority of clinical decision making is subjective about limb salvage. There are objective criteria for assisting the clinician with the vigorous task of deciding functional limb salvage (Table 1).
| Table 1. Criteria For Deciding Limb Salvage |
| I. Wounding Local, sharp... Wide, crush Soft tissue & Skeletal Injury
II. Neurologic Function III. Ischemia IV. Systemic Response V. Age |
The various predictive scoring schemes4,6,7,8 are all based on the assessment of the data in Table 1 and are weighted based on the impact that each variable would have on eventual outcome.
It is extremely useful to catalog the nature and extent of the injury to the limb components, i.e., skin, bone, muscle, vessel, nerve, and local contamination as recommended by Mueller, et al5. The documentation and enumeration of the injuries to each component help establish the likelihood of a limb that the patient will comfortably use. Limbs with extensive crushing (Figure 2) to the soft tissue elements (muscle) although salvaged as an appendage may not function as desired or may be dysfunctional and neuropathic. Large zones of crush injury are predisposed to higher rate of infection due to the concomitant muscle hypoxia and secondary necrosis that develops. No antibiotic regimen has been shown to effect the infection rate of this type of injury induced infection. The timely removal of all dysvascular and avascular tissue is the only proven prophylactic maneuver.
 |
Figure 2. Crushing Mechanism: Typical large zone of injury following industrial accident. Note the extent of wounding of entire leg. Local flaps are not indicated here. |
The quantity of muscle that can be debulked and still maintain a functional limb varies with the preinjury muscle mass, and the presence of injuries that may prevent normal ankle motion. Large zones of injury of this nature often develop secondary problems as the injury evolves over time. For example, the crushed limb with a proximal arterial injury is revascularized in a timely manner. However the zone of injury being large required a lengthy interposition graft. Although the distal limb is now adequately perfused and by all accounts the procedure is successful the intercalary zone of injury is now bypassed by the interposition graft and hence has no blood supply in that region as previously supplied by the local muscle branches. This scenario has been coined the "Interstate syndrome" as the blood supply has rapid flow to the foot, but no off ramps to the nutrient vessels along the way, and like the small towns along thruways the muscle begins to die, and fibrose over time. We presently do not have the technical ability to successfully revascularize individual muscles within the zone of injury, and the avascular zones now also contribute to the delayed union or nonunion of the skeletal injury. Nonunion and infected nonunion of the skeletal injury was a major reason for many delayed amputations. The insight to predict this type of outcome is necessary to prevent the commitment of resources to a project that is doomed to fail.
The first order of care is to determine what treatment is best suited for the individual and finally the individual injury itself. Patients with multiple system involvement (Injury Severity Score > 25)5 often simply cannot withstand the persistent toxic load that a mangled extremity presents to them without exacting a toll on the overall system. Early amputation therefore is part of the life saving process that must be considered even though the limb may be potentially salvageable.
Often the surgical exercises of limb salvage are needed to restore function to the limb without the limb ever being at risk from a physiologic standpoint. A typical example of this would be the young laborer who presents with a large crushing mechanism and a resultant wedge type fracture of the tibia and fibula. Although the skin envelope is intact, the injury itself carries the same prognosis as an open (Gustilo type III A)5 fracture. Therefore the treatment scenario is essentially that of limb salvage if one wants to restore maximum function.
The modalities employed and the treatment tenets are the same:
The same tenets are expounded upon as the injury severity and tissue components increase. The next step in limb salvage would be arterial reperfusion, and this is usually reserved for the reimplantation type of scenarios as they pertain to the lower extremity. Fortunately the lower extremity, because of the three vessel system, can be adequately maintained with two or even one remaining vessel provided that ample muscle perfusion and viability exist. Temperature intolerance will cause discomfort, but infrequently it will produce dysfunction particularly in this region of the country. Injuries at the popliteal level have a poor prognosis for functional return except in the younger population, despite the technical ability to achieve reperfusion2,3,5. The mechanism of injury necessary to produce such an injury at this location generally precludes a normal resultant soft tissue envelope.
Skin, muscle, periosteum, bone, and vessels are the tissues that many of us as orthopaedists deal with on a daily basis, however, frank nerve injury — axonotmesis — is infrequently encountered and less frequently addressed by the general practicing physician. The function of the limb is determined by the functioning of both motor and sensory nerves. For the leg this would primarily be the posterior tibial nerve as it both renders protective sensation to the limb and motors the foot flexors. Classic limb salvage as envisioned by many involves the reanastomosis of the vessels and the microscopic repair of the nerve: replantation. Although nerve repair is employed in selected cases of limb salvage, generally speaking, patients with this compendium of injuries to all the tissue elements inclusive of the nerve benefit from primary amputation.
The direct cost incurred with limb salvage is approximately twice that of early amputation ($109,000 vs. $65,000)1 and indirect costs increase due to the lengthy rehabilitation that often accompanies a salvage (11 months vs. 3 months). The direct and indirect cost of prosthetic wearers averages three times that of the reconstructed patient in the first four years, yet their loss of wages during that time is less.
1. Attempt to attain definitive fixation at the index procedure. Spanning (temporary) external fixation or skeletal traction is a weak substitute and does not allow care of the soft tissue nor adequate pain relief for the patient in most cases. Long bone injuries are ideal for medullary rod stabilization with the advantage of being less intrusive for the possible soft tissue reconstruction that may be forthcoming from the plastic surgery team (Figures 3A, 3B, 3C). Tourniquet application should be avoided at all costs to prevent additional osseous ischemia except in cases of ongoing uncontrolled hemorrhage. Definitive frame external fixation remains a useful alternative particularly with cases involving bone loss.
 |
 |
 |
| Figure 3A, 3B, and 3C. Young man with open fracture of tibia with concomitant bone and soft tissue loss. Salvage of length possible only with free tissue transfer (latissimus dorsi) that allows repeated elevation and serial bone grafting. | ||
2. Articular injuries require early repair/reconstruction as the inevitably associated periarticular muscle damage will predispose one to stiffness or deformity unless the joint can be mobilized, or placed in a functional position. The ability to attain an anatomic reduction of the joint decreases with time from the injury for most surgeons.
3. Less then 50% of the skeletal injuries undergo primary union during their care. Therefore secondary interventions must be planned with the patient and family early in the treatment. As alluded to previously this population of patients averages seven surgical procedures over the course of salvage, therefore the classic definition of delayed union does not apply to this type of injury. Many studies today find that secondary intervention, i.e., bone graft, and revision rodding are best performed within 3 months of the index procedure. This potentially shortens the treatment phase of limb salvage.
1. Tourniquet application should be avoided at all costs to prevent secondary tissue ischemia.
2. The size of the skin wound does not correlate precisely with the zone of injury. Therefore the debridement is not solely determined by the size of the presenting wound. The ability to deduce the pattern of injury and the mechanism by which the soft tissue was violated is necessary to perform proper surgical debridement of the zone of injury. An accurate description of the mechanism from the prehospital team is critical to the deduction process.
3. Hypoperfusion of the tissue is the precursor of infectious focus. Unreduced long bones or excessive traction can prolong tissue ischemia creating a larger zone of injury.
4. The injury oftentimes is one in evolution, and care must be exercised to reduce the zone of injury from extending beyond that of the epicenter of initial energy dissipation.
5. Tissue within the zone of injury are generally poor candidates for coverage procedures, i.e., gastrocsoleus complex.
6. Compartment problems can still occur with open fractures unless adequately released surgically.
7. Foot compartments communicate with the lower leg and can significantly compromise eventual outcome if not recognized as being involved.
8. The judicious use of splinting in the immediate post operative period aids in the reduction of swelling, and thereby improves oxygenation of the tissues. The communication of foot and leg compartments mandates the splinting of the foot even though the injury is seemingly contained to the leg itself.
Hammertoes, clawtoes, equinous contractures: Functional salvage of the lower extremity requires a vast array of anatomic criteria for the patients to be truly satisfied (Figures 4A,4B,4C). To stand comfortably one must obtain and maintain a plantigrade foot. The difficulty with such following complex injuries results from the large muscle mass that becomes densely scarred. The presence of stiff phalangeal joints can prevent not only shoeing, but normal gait. The ability to walk with a minimal limp requires ankle dorsiflexion to exceed ten degrees, as this is the source of stepoff power in the gait cycle.
Knee stiffness, instability: Stance and stride, the basic elements of the gait cycle, requires the ability to obtain full extension, or gait related fatigue develops. Knee instability as a result of the high energy injury generally becomes knee stiffness from the depth of the injury to the extremity.
Infection, chronic pain: Infection is a constant factor in the salvage process that one contends with. The etiology is that of tissue hypoxia, and vascular injury. The lack of perfusion at the time of contamination prevents the local host from protecting itself. Chronic pain can come from a multitude of sources: the crushing of major nerves, large zones of scarring, articular cartilage fibrillation. Unfortunately, many of these sources are determined at the time of injury, and during the salvage process the goal is to diminish their effect on outcome.
Limb length inequality is a common problem associated with severely mangled extremities (Figure 4C), as often it is necessary to remove large segments of bone during the debridement process due to obvious nonviability, or dysvascular tissue with gross contamination. The intentional foreshortening of the limb is necessary to achieve nerve repair or to reduce the soft tissue defect. Inequality is better tolerated and compensated for in the femoral component as opposed to the tibia. Five centimeters or greater of inequality creates the need for additional procedures. Lengthening of the involved extremity or shortening of the uninvolved extremity are two options that must be discussed with the patient. The functional impairment from length inequality stems from both physical and psychological sources. Lengthening procedures through the zone of injury (so called distraction osteogenesis) mandates, by design, an increased treatment time and additional hospitalizations. Patients must be carefully selected for this treatment modality as it is labor and psychologically intensive for the adult patient and their family.
 |
 |
 |
| Figures 4A, 4B, 4C. Limb salvage complications. 4A. Severe dysfunctional equinus contracture following limb salvage. 4B. Painful clawtoes from dense scarring of the deep posterior compartment crush. Modifications in shoes required for functional return, desired correction at two years. 4C. Shortening of extremity. Patient remained functional with lift until lengthening procedure at four years. | ||
The early access to skilled therapists is paramount to success with any surgical endeavor, and nowhere is this more evident than with limb salvage patients. The need for targeted and extensive therapy is real and the demands enormous. The modalities that are required for soft tissue release, neuromuscular reeducation, scar and pain relief can be taxing for any physical therapist. The team of therapists need to be involved early and often.
Limb salvage was previously considered successful if the anatomic structure was retained and viable. We have come to learn that function, and patient satisfaction are equally important parameters to contend with. The rate of secondary amputation for lower limb injuries undergoing limb salvage averages 25% within the first two years after seemingly successful limb salvage. Limb salvage in the era of cost containment and limited resources will entail restoration of function and limited disability and improved patient satisfaction, a daunting task to say the least. We will not abandon the progress that has been made to date, but the need to understand what truly is best for our patients is paramount. The success of limb salvage surgery is squarely on the shoulders of the physician and our ability to convey the realities of the salvage process to our patients such that unrealistic expectations do not cause early psychologic failures.
[dcms-footer.htm]