Soft-Tissue and Skeletal Wound Management in the Setting of Vascular Injury

Introduction

Extremity injuries involving significant trauma to bone, soft tissue, and major vessels are relatively uncommon outside of the wartime setting. This constellation of injuries may also be referred to as the mangled extremity. Much of the difficulty encountered in managing patients with a mangled extremity is due to the fact that few surgeons gain much experience in dealing with this challenging injury pattern. In order to meet this challenge, such injuries are best dealt with by a multidisciplinary team that combines the subject-matter expertise of vascular, plastic, and orthopedic specialists. The purpose of this chapter is to consider the nature of the extravascular component of severe limb trauma, the priorities in reconstruction, and the sequencing of interventions in order to furnish the vascular surgeon with the key imperatives of soft-tissue and skeletal management as understood by their orthopedic and plastic surgical colleagues.

Epidemiological Factors

The likelihood of fracture-associated extremity vascular trauma depends on the nature of the associated orthopedic injury, with an overall incidence estimated to be less than 1%. However, certain orthopedic injury patterns, such as posterior knee dislocation, mandate a higher index of suspicion. Young et al. found an incidence of 9% of vascular injuries in a series of 661 civilian open tibial shaft fractures. These had an amputation rate of 38% compared to a rate of 5% in open fractures without vascular injuries. Vascular injuries may also be more commonly associated with fractures in the high-energy ballistic and blast environments of military trauma. From a database of 679 patients with military extremity trauma, Brown et al. identified 34 patients and 37 limbs with vascular injury. In only nine of these limbs was the vascular trauma not associated with a corresponding fracture. The authors of this study noted that outcome was worse in patients with combined orthopedic and vascular injury, and this was attributed to the unfavorable soft-tissue sequelae of energy transfers sufficiently large to cause bone fracture. This finding is also consistent with examples of high-energy extremity wounds reported in the civilian literature. In an Israeli report of 35 casualties, both military and civilian, Romanoff revealed that of 35 combined orthopedic and vascular injuries, 14 (40%) involved the femoral vessels, 9 (26%) compromised the popliteal vessels, and 8 (23%) involved the brachial artery. Upper limb injury complexes were often related to gunshot wounds compared to lower limb injuries. In Brown's series (reporting experience from the British military), 11 injuries (30.5% of all cases) involved the upper limb, with 7 involving the brachial artery, and 4 involving the radial and/or ulnar arteries.

The orthopedic injury most commonly associated with a vascular injury is dislocation of the knee, particularly when the dislocation is posterior in nature. The orthopedic injury is of relatively low priority in the initial management of the patient as the knee will usually be easy to reduce and, in some cases, may have been reduced before the vascular injury is appreciated. In general, the majority of these will be closed injuries. In a literature review totaling 245 knee dislocations with a 32% incidence of vascular injuries, time to revascularization was the most important factor in determining outcome. The authors described a salvage rate of 89% when this was carried out in less than 8 hours, compared to an amputation rate of 86% when the delay was greater than 8 hours. A prospective report, undertaken as part of a multicenter study depicting the outcome of severe lower limb injuries described 18 patients, of whom 4 (22%) required amputation (a figure that is relatively consistent in the literature). Despite successful salvage, patients still had a moderate to high level of disability 2 years after the injury; the knees were stiffer and weaker; and only two were stable in all directions.

Grading of Open Fractures

Open fractures represent a heterogeneous group of injuries, but the relationship between extent of tissue damage and likelihood of limb salvage and functional recovery has been recognized for decades. As such, a formal system for grading the severity of open fractures was introduced by Gustilo and Anderson in 1976 ( Table 26.1 ). This remains a universally accepted classification of the wound associated with an open fracture, relating especially well to the risk of infection. For Gustilo type I fractures, an infection rate of 1% or less can be expected, and for type II fractures, a rate of approximately 3% has been reported. Since the original description, it has been recognized that those with type III fractures are a large and heterogeneous group, and, to reflect this, a modification to the original grading was made with subdivision of type III fractures as follows:

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  Type IIIA—Adequate soft-tissue cover of the bone despite extensive laceration

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  Type IIIB—Extensive soft-tissue loss, with periosteal stripping and exposed bone. Usually associated with massive contamination

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  Type IIIC—Open fracture with vascular injury that needs repair

For type IIIA fractures, an infection rate of 17% has been reported, and for type IIIB, 26%. However, lower infection rates are achievable. Wordsworth et al. reported a 1.6% infection rate in a series of 65 patients with IIIB open tibias. Type IIIC fractures have a variable infection rate, depending on the soft-tissue injury and the time to revascularization. A proportion of IIIC injuries require amputation due to lack of reconstructive options, and late infection is of less relevance as an outcome measure in this group. A series of 661 open tibial shaft fractures showed an amputation rate of 38% for IIIC injuries compared to a of rate 5% in IIIB injuries. The relative rarity of these injuries, combined with their heterogeneous nature, means that meaningful comparison of outcomes (either between different papers or even between patients reported in the same paper) is difficult, if not impossible.

Salvage Versus Amputation

In essence only the following three decisions are available to the surgeon managing an extremity injury where limb ischemia is present: perform primary amputation, defer primary amputation to a later date, or attempt surgical intervention with a view to limb salvage. The latter may involve a lengthy or complex revascularization procedure, definitive fracture fixation, and soft-tissue coverage extending to microvascular tissue transfer. There are inherent risks of attempted limb salvage as the procedures may be costly in terms of patient reserve and risk of mortality, need for multiple operative procedures, and prolonged rehabilitation.

“Successful limb salvage” is a subjective phrase: outcomes can be variably defined according to patient factors such as pain, function, return to work, and satisfaction. Expectation of recovery varies according to the individual. Younger patients tend to have higher levels of preinjury activity, and rehabilitation will be concordantly longer in order to ensure recovery to previous functional capability. In contrast, the older, less-mobile population may have lower expectations. Expectation management forms a key part of the duty of the multidisciplinary team in cases of limb salvage or amputation, with regular and consistent counseling of the patient and their relatives in order to allow realistic but positive interpretations of recovery potential.

Studies have reported the long-term outcomes and quality of life in limb-salvage patients with open tibial shaft fractures and severe soft-tissue loss compared to amputees. Limb-salvage patients took longer to achieve full weight-bearing status, were less willing or able to work, and had a significant loss in range of movement at the ankle. Fairhurst et al. demonstrated that early amputees had higher functional scores, fewer operations, and returned to work and sporting activities within 6 months. They concluded that early amputation was better when confronted with a borderline salvageable tibial injury. However, reports from a prospective multicenter trial of 556 patients (the Lower Extremity Assessment Project [LEAP]), reported no difference in functional outcomes between patients who either underwent limb-salvage surgery or early amputation at 2-year and 7-year follow-up points. The level of amputation was a further predictor of outcome. Further analysis of the difference in cost analysis of limb salvage, and amputation has shown that the latter is significantly more expensive if the ongoing maintenance and replacement costs of the prostheses are included.

Several scoring systems have been developed to help guide the decision as to whether or not to amputate after severe lower limb trauma, and they have been designed to augment subjective clinical impression with objective assessment based on specific criteria. In their retrospective review of 58 severely injured limbs, Bonanni et al. showed low sensitivities of Mangled Extremity Severity Score (MESS) (22%), limb-salvage index (61%), and predictive salvage index (33%). The LEAP study assessed MESS, predictive salvage index, limb-salvage index, nerve injury; ischemia/soft tissue contamination; skeletal; shock; age (NISSA); and Hannover Fracture Scale (HFS)-97. The authors reported a high specificity but much lower sensitivities for the scores than those reported by the developing authors. The performance decreased further when immediate amputations were excluded. A further study from the same group suggested that lower limb extremity scores do not predict short- or longer-term functional outcome. Overall, scoring systems have not proven to be useful for prospective clinical decision making and are not widely used for this purpose—the final decision to salvage a limb must be tailored to the patient, their injury, and their future functional goals.

Strategies in Managing the Severely Injured Limb