The diagnostic approach to extremity trauma has changed dramatically over the last few decades. Initially, the influences from combat experience lead to the aggressive approach of mandatory exploration for all penetrating trauma to an extremity. However, application of this policy to civilian injuries resulted in negative exploration rate as high as 84% in penetrating trauma patients [31]. These patients had undergone expensive, nontherapeutic operations which resulted in additional morbidity.

With the availability of arteriography in most trauma centers, this diagnostic modality supplanted wound exploration for penetrating extremity trauma. As was the case with wound exploration, mandatory or routine screening arteriography for proximity wounds, in the absence of other suspicious clinical findings, resulted in a large proportion of normal arteriograms (90%), at significant cost [1]. In addition, arteriograms were found to be less than perfect, having a low, but real, incidence of false-negative and false-positive findings. Because of its invasive nature and the potential nephrotoxicity of contrast media, arteriography also occasionally results in serious complications, thus increasing patient morbidity and further increasing the cost of care.

Due to the increasing amount of unnecessary angiograms being performed in the trauma setting, clinicians began to look for better ways to identify arterial injuries. This leads to the evaluation of injury location and its proximity to major vascular structures in determining when to proceed with angiography. Weaver et al. examined the yield of a vascular injury when proximity alone was the sole indicator for angiography in extremity trauma [32]. Over an 18-month period, 373 patients with penetrating trauma distal to the deltopectoral groove in the upper extremity and distal to the inguinal ligament in the lower extremity were evaluated. Arteriograms were obtained for patients with a hard or soft sign of vascular trauma (Table 35.1) or in the absence of these findings, when the path of the penetrating object was judged to be in close proximity to a major vascular structure. In the 216 patients with abnormal physical findings, an arterial injury was identified by arteriography in 65 (30%), whereas in the absence of physical findings (157 patients), only minor injuries were identified in 17 (11%). Only a pulse deficit, neurologic deficit, or shotgun injury correlated (p < 0.05) with arteriographic evidence of a major arterial injury.

Later, authors from the same institution sought to validate the utility of ABI in assessing patients with penetrating vascular trauma of the extremity. A follow-up study investigated the ability of Doppler indices to detect occult arterial injuries in a consecutive cohort of 514 patients with unilateral, isolated penetrating extremity injuries [33]. Arteriography was limited to patients with a pulse deficit, neurologic deficit, shotgun injury, or one or more “soft” signs or an ABI of less than 1.0. All patients with arteriographic evidence of a major arterial injury had either a pulse deficit or ABI below 0.9.

Selective use of angiography in evaluation of patients with penetrating extremity trauma was further supported by Conrad [34]. Five hundred and thirty-eight patients were reviewed retrospectively. Similar to previous studies, angiography was limited to patients presenting with an abnormal pulse exam or Doppler indices less than 1.0. Patients with a normal physical exam and Doppler indices of 1.0 or greater were discharged home without further workup. Three hundred patients with asymptomatic proximity wounds and normal physical exam were discharged home. Fifty-one percent of these discharged patients were available for an average follow-up of 9.8 months. There were no missed injuries or late complications identified in the group.

For blunt extremity trauma, the indications for arteriography parallel what has been established for penetrating injuries. A prospective study analyzed the results of arteriography in 53 patients with unilateral blunt lower extremity trauma [35]. Thirty-one patients had physical findings suggestive of an arterial injury, and an arterial injury was demonstrated in fifteen. A pulse deficit or decrease capillary refill correlated significantly (p < 0.05) with arteriographic evidence of injury. Of the 15 arterial injuries, 12 were found in patients who had one or both of these findings, and four of those injuries required repair. In the remaining 22 patients with neither a pulse deficit nor decreased capillary refill, three minor injuries were found, none of which required repair.

Another series of blunt injuries focused specifically on 115 patients with knee dislocations [36]. Popliteal artery injury was demonstrated arteriographically in 27 of 115 (23%) patients. An abnormal pedal pulse identified popliteal artery injuries with sensitivity of 85% and specificity of 93%. All injuries that required intervention were associated with a diminished pulse. Dennis reported an identical experience in 37 patients with knee dislocations [37]. In all patients who required popliteal repair, pedal pulses were absent. More recently, Abou-Sayed and Berger confirmed the sensitivity of physical examination in 52 patients with blunt popliteal artery injuries [38]. Twenty-three patients, with a normal pulse examination, did not undergo angiography and required no vascular interventions. Angiography was performed in 13 patients with normal pulse examinations (at the discretion of the attending surgeon); similarly, no clinically significant lesions were identified that required intervention. Again, the assertion that the clinical examination can define a subset of high-risk patients who need an arteriogram, and possibly surgical repair, was validated.

Based on these published reports, a consensus has developed that for penetrating or blunt extremity civilian trauma, arteriography is indicated only for patients with either an abnormal extremity pulse examination or Doppler index less than one. Careful physical examination and pressure measurements appropriately select the vast majority of patients (>95%) who have significant arterial injury and require arteriography.

Plain films are part of a standard diagnostic evaluation for a trauma patient. In patients with blunt trauma, fractures or dislocations in key anatomical areas may alert the clinician to the possibility of a vascular injury (i.e., posterior knee dislocation). Radio-opaque markers placed at the point of entry and exit of penetrating trauma wounds may be helpful in determining the trajectory of the penetrating object. Attention to all foreign bodies should be given. In the special situation of a repeat trauma patient, the clinician must be aware of possible retained foreign bodies from prior trauma.

Duplex ultrasound combines pulse-wave Doppler flow analysis and high-resolution B-mode ultrasound for site-specific assessment of artery and vein injury. Because of continued improvements in noninvasive vascular imaging, color flow duplex (CFD) ultrasound has been utilized as a substitute for, or to complement, arteriography [39]. CFD has several obvious advantages: it is noninvasive, painless, and portable and can easily be brought to the patient’s bedside, emergency room, or operating room. Repeated and follow-up examinations are easily performed without morbidity and are relatively inexpensive. The duplex is also able to detect vascular injuries to non-conduit vessels such as the profunda femoral artery, where ABI measurements would be registered as normal.

Bynoe and colleagues reported sensitivity of 95%, specificity of 99%, and accuracy of 98% when CFD was used to evaluate blunt and penetrating injuries of the neck or extremities, and Fry and coworkers [40, 41] documented 100% sensitivity and 97.3% specificity in a similar series. In these two studies, however, a comparison arteriogram was available for only a minority of patients. Bergstein and associates reported on 67 patients who had 75 penetrating extremity injuries, all of whom underwent both CFD and arteriography [42]. Using arteriography as the gold standard, CFD had two false-negative results and one false-positive (sensitivity 50%, specificity 99%). Gagne and coworkers published a series of 37 patients with proximity injuries in 43 extremities [43]. Arteriography identified three injuries to the deep femoral, superficial femoral, and posterior tibial arteries that were not identified by CFD. However, CFD did detect a superficial femoral artery intimal flap that arteriography missed.

Despite some uncertainty about the ability of CFD to detect all arterial injuries, these reports suggest that nearly all major injuries that require therapeutic intervention can be identified, potentially at considerable costs savings as compared with arteriography [39]. Ordog has estimated a multimillion dollar cost savings if CFD and outpatient follow-up, rather than arteriography and inpatient observation, were used to exclude extremity arterial injuries [44].

Contrary to the success of these reports, use of CFD in the work up of trauma patients presents some challenges. Technician dependence, limited availability during off hours, limited visualization of the chest and, in some cases, the abdomen, and penetrating injuries to zones I and III of the neck are possible pitfalls of CFD. Our institutional experience with CFD in the evaluation of extremity trauma confirmed the operator dependence of CFD, and, we felt for CFD to be used effectively, an institutional investment in experienced vascular technologists and interpreting physicians would be required [45]. This expense could be lessened over the long term if the current effort to train surgeons in the use of diagnostic ultrasound for intracavitary trauma was extended to include extremity vessels.

Years ago, computerized tomography angiography (CTA ) began challenging the need for digital angiography in the evaluation of trauma patients with suspected vascular injuries. However, now with advances in technology to newer 64-row multi-detector CT scanning, digital angiography is being supplanted by CTA in many trauma centers [46–49]. Current scanners with multi-detector scanning and three-dimensional reformation capabilities provide rapid acquisition of isotropic data sets of long vascular territories within seconds. Therefore, CT scanning can now integrate extremity images in the routine thoracoabdominal trauma imaging without a significant increase in scanning time. When compared to digital angiography for trauma patients, CTA has the distinct advantage of being equivalent in accuracy, more time efficient, less invasive, and less expensive in the diagnosis of traumatic vascular injuries. Current CT scanning is also readily available and provides simultaneous imaging of surrounding body structures and adjacent anatomical locations in a single examination. Through remote computer access, set injection protocols, and lack of arterial puncture complications, staff radiologists can provide diagnostic reading offsite.

CT scan evidence of a vascular injury includes the following findings: contrast extravasation, extravasated contrast material collections (Fig. 35.1), loss of opacification or occlusion of arterial segment (Fig. 35.2), abrupt vessel narrowing (signifying either spasm, dissection, or external compression), early venous opacification (signifying an arteriovenous fistula), and an abnormal vessel caliber or course [49] (Fig. 35.3).

Soto and colleagues performed one of the early comparisons between CTA and digital angiography for evaluation of suspected vascular injuries in extremity trauma patients [50]. In this study, all extremity trauma patients referred for digital angiography underwent CTA. Two independent observers documented sensitivity and specificity levels greater than 90%, respectively, for diagnosis of vascular injuries, with an interobserver agreement of 0.9 (kappa statistics). More recently, studies from institutions with more advanced CT scan technology confirmed the diagnostic utility and accuracy in the evaluation of trauma patients [47, 48]. Inaba and associates utilized multi-detector CT scan angiography for 59 trauma patients with lower extremity injuries and documented 100% sensitivity and specificity in the diagnosis of a clinically significant vascular injury [51]. The one missed injury in their patient cohort was secondary to artifact from a retained missile fragment. Most recently, Inaba and colleagues followed up their earlier study and reported similar findings [52]. Sensitivity and specificity both reached 100% in detecting clinically significant traumatic vascular injuries of the lower extremity. A systemic review looking at this topic found the sensitivity and specificity of CTA to be 96.2% (95% CI 93.5–97.8) and 99.2 (95% CI 96.8–99.8%), respectively. CTA was non-diagnostic in 4.2% of cases [53]. Another review article sited CTA sensitivity and specificity to be 95–100% and 87–100%, respectively, for the evaluation of femoropopliteal and mid- to proximal upper limb vascular injuries, and accuracy improved as CT scans improved [54]. The shortcoming of computed tomography continued to appear in artifact formation from retained missile fragments. Other recognized disadvantages of CT angiography include artifact formation due to motion or calcified plaques and high volume of iodinated contrast usage. If an endovascular treatment option is contemplated, deleterious effects of sequential intravenous contrast boluses must be considered in the patient management.