Key Words:
vascular , injury , trauma , blood vessel , shunt , damage control surgery , ligation , temporary vascular control , extremity vascular injury , truncal vascular injury
“We should not rest content with the work of our predecessors, or assume that it has proved everything conclusively, on the contrary it should serve only as a stimulus to further investigation.” Ambroise Paré
Introduction
The past 20 years has witnessed a fundamental change in the management of the severely injured patient. Perhaps the most notable change is the concept of the damage control or staged laparotomy. Stone and colleagues provided the landmark description of a staged operation in trauma in 1983. With intent to limit the physiologic burden on an already-threatened patient, they demonstrated a significant survival advantage in a series of 17 patients. Later coined by Rotondo et al as “damage control surgery,” this concept of limiting the “bloody vicious cycle” of hypothermia, acidosis, and coagulopathy has been embraced by nearly every major trauma center with reproducible results. One of the major tenets of staged laparotomy as described by Stone and colleagues was the attention to control and repair of major blood vessel injuries. Hemorrhage (and, subsequently, hemorrhagic shock) is perhaps the most significant factor contributing to the triad of coagulopathic bleeding. Incidentally, the management of injured blood vessels in a severely injured patient is often arduous, technically demanding, and time-consuming, all of which can force ligation out of desperation. This chapter provides a review of a renewed technique that offers a viable alternative to ligation and that adheres to the mantra of damage control—temporary intravascular shunts.
Temporary vascular shunts have many benefits in the multiply-injured patient. Not only do they allow for reperfusion and/or venous decompression across the injured vessel, but they also afford time to transport a patient to a higher level of care or to manage concomitant life-threatening injuries. In this context, “extra time” means that flow is restored across the injured artery and/or vein through the shunt while resuscitation, orthopedic fixation, cranial decompression, or other damage control procedures are performed.
Historical Use of Intravascular Shunts
The concept of an implantable prosthetic conduit has a long history with first descriptions in World War I by Tuffier and Makins. These paraffin-lined silver tubes were initially proposed for the perceived advantages of sutureless technique and were meant for permanent placement. The goal was not long-term patency of the conduit but rather a temporary means of perfusion that would provoke collateralization as the tube slowly occluded. In 1932, Blakemore and Lord introduced use of a new composite alloy called Vitallium (composed of cobalt, chromium, and molybdenum). Initially, the Vitallium tube was internally lined with vein graft; but this was soon followed by a two-tube method with interposed vein, again as a sutureless technique ( Fig. 17-1 ). Despite theoretical advantages and widespread dissemination in World War II, the use of such tubes was limited by logistics and by frustratingly prolonged medical evacuation times of the wounded to the surgical facilities.
Experimental use of intravascular shunts as a means of temporary restoration of blood flow has roots to both the French-Algerian war (1954-1962) and more extensively to the Soviet war in Afghanistan (1981-1985). An excellent synopsis of the Russian experience with temporary vascular shunts in Afghanistan and the Northern Caucuses is provided in the international section of this edition. Both accounts described use of temporary vascular shunts to maintain blood flow to allow time either for onward transport or to “administer antishock therapy.” Among the first modern descriptions of temporary intravascular shunts is from Eger et al, who in 1971 used a temporary vascular shunt prior to orthopedic fixation. This practice ultimately demonstrated a decreased frequency of extremity amputation in the setting of complex popliteal artery injury.
Modern Use of Intravascular Shunts
Despite advances in civilian damage control surgery, use of temporary vascular shunts in trauma had been limited to a few case series prior to the events of September 11, 2001 ( Table 17-1 ). One bittersweet effect of wartime is the renaissance of surgical experience, technology, and technique. In a report from Operation Iraqi Freedom (OIF), Rasmussen et al described a 1-year experience of 126 extremity vascular injuries, in which 30 temporary vascular shunts were utilized in the management of vascular injury. In this report, shunts were used as damage control adjuncts to either facilitate casualty evacuation or to allow perfusion while other life-threatening injuries were managed. In this series, 57% of the patients had patent shunts on arrival to a higher level of care (typically less than 2 hours after initial surgery). The authors noted that patency of the shunts hours after placement was higher (86%) when they had been used in larger, more proximal vessel injuries. The favorable experience with the use of vascular shunts in this initial report was corroborated by subsequent series provided by other combat surgical teams. Figures 17-2, A-C detail a case example in which a midsubclavian injury was initially treated at a forward surgical location with the insertion of an intraluminal shunt and subsequently was repaired with interposition graft at a higher level of care.
| Series | Publication Year | #Number of Patients |
|---|---|---|
| Hossny et al | 2004 | 9 |
| Sriussadaporn et al | 2002 | 7 |
| Reber et al | 1999 | 7 |
| Granchi et al | 2000 | 19 |
| Husain et al | 1992 | 5 |
| Khalil et al | 1986 | 5 |
| Nichols et al | 1986 | 13 |
| Johansen et al | 1982 | 10 |
Gifford and colleagues provided one of the only studies to characterize longer-term extremity outcomes following the use of temporary vascular shunts. In their study, the authors used case-controlled methodology to show that the use of temporary vascular shunts had no adverse outcome in the years following vascular repair and likely extended the window for limb salvage, especially in the most severely injured extremities. Finally in a recent and larger 10-year review of the civilian experience from Feliciano’s group at Grady Memorial, Subramanian et al confirmed the utility of temporary vascular shunts in certain patterns of vascular injury. This study demonstrated a 95% patency rate of shunts and an overall survival rate of 88% following major vascular injury. In this series of 101 vascular shunts, the authors documented a secondary amputation rate of 18% ( Table 17-2 ).
| Review | Year | Shunt Location | Shunt Type and Number | % Patency * | Average Shunt Time | Early (<30d) Secondary Amputations † | Shunt-Related Complications ‡ | |||
|---|---|---|---|---|---|---|---|---|---|---|
| Rasmussen et al (combat) | 2004-2005 | 30 arterial 4 venous | Javid | 16 | Arterial | Proximal | 86% | <2 hr | 2 | 0 |
| Argyle | 12 | Distal | 12% | |||||||
| Sundt | 2 | Venous | Proximal | 100% | ||||||
| Taller et al (combat) | 2006-2007 | 14 arterial 9 venous | Javid | NL | Arterial | Proximal | 100% | ~5 hr | 0 | 0 |
| Argyle | NL | Venous | 89% | |||||||
| Unknown | NL | |||||||||
| Chambers et al (combat) | 2004-2005 | 18 arterial 11 venous | Javid | NL | Arterial | Proximal | 86% | ~1.5 hr | 3 (1) | 0 |
| Distal | 50% | |||||||||
| Sundt | NL | Venous | 82% | |||||||
| Borut et al (combat) | 2003-2007 | 42 arterial 8 venous | Argyle | NL | NL | NL | NL | 4 (0) | NL | |
| Sundt | NL | |||||||||
| Javid | NL | |||||||||
| 12 Fr feeding tube | NL | |||||||||
| Subramanian et al (civilian) | 1997-2007 | 72 arterial 29 venous | Argyle | 61 | Arterial | 91% | 23.5 hr | 10 (1) | 0 | |
| Chest tube | 16 | |||||||||
| Pruitt-Inahara | 20 | |||||||||
| 5 Fr feeding tube | 1 | Venous | 100% | |||||||
| 16 ga Angiocath | 1 | |||||||||
* Proximal = brachial artery and proximal in upper extremity or popliteal artery and proximal in lower extremity.
† Parentheses = secondary amputations attributable to shunt thrombosis.
‡ Shunt-related complications = shunt displacement, bleeding, or thromboembolism.
Indications
Damage control—that is, physiologic instability or higher operative priorities precluding definitive reconstruction of an encountered vascular injury—is the primary indication for the use of a temporary shunt. The rapid placement of a shunt is useful to reduce the time to reperfusion (i.e., oxygen delivery) beyond the vascular injury when other higher-priority management steps are required. With the shunt in place, stabilization of associated fractures or performance of a laparotomy, craniotomy, or thorocotomy can be completed with the extremity or other end-organ perfused instead of ischemic. Finally, expedited placement of a shunt may be useful if a surgeon desires to curtail the intervention due lack of training in or currency with major vascular reconstruction. Placement of a shunt in the setting of prolonged ischemia provides end-organ perfusion and may even allow the infusion of medications designed to limit thrombosis or ischemia-reperfusion injury (e.g., heparin or mannitol). Use of a temporary vascular shunt in an axial vessel of a severely mangled extremity allows for the limb to be stabilized, débrided, and reassessed at a second-look operation if needed. This strategy allows for a more-organized mobilization requisite of surgical disciplines to assess the limb at a scheduled time after the initial operations has been performed. The indications for the use of temporary shunts are provided in Table 17-3 .
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Shunt Materials
Many hollow tubular devices have been described to function as temporary vascular shunts including large-bore angiocatheters, sterile intravenous tubing, endotracheal tubes, feeding tubes, and small-caliber chest tubes. While these improvised shunts may provide temporary flow, they are not designed for this purpose, are predisposed to causing vessel injury, and are prone to thrombosis due to a number of physical characteristics. Currently there are no commonly used FDA-approved shunts for trauma, and surgeons must rely on off-label use of devices designed for use during carotid endarterectomy and other cardiovascular operations for age-related disease. Examples include the Javid (Bard PV, Tempe, AZ), Argyle (Covidien, Mansfield, MA), Sundt (Integra, Plainsboro, NJ), and Pruitt-Inahara (LeMaitre Vascular, Burlington, MA) shunts. There are no studies that have compared the effectiveness of these shunts to one another in the setting of trauma, and any one or more may be used for vascular trauma even at the same institution. Nevertheless, extrapolation from translational hemodynamic and hydrodynamic studies of commonly used shunts seems to favor larger-diameter, in-line (shorter) shunts as they tend to produce higher flow rates and distal perfusion pressures. Aufiero et al also recommend the use of tapered shunts when smaller diameter shunts (<12 Fr) are required.
Several physical characteristics must be weighed when selecting the type of shunt to use, and a list of features of commonly used devices is provided in Table 17-4 . In-line shunts are shorter and useful when operative space is limited and when the gap in or injury to the vessel is short. In-line shunts lie inside of the injured vessel and, once in place, are not likely to become entangled with wound dressing material, surgical retractors, orthopedic fixator devices, or monitor wires, which often surround the injured extremity ( Figs. 17-3 and 17-4 ). Looped shunts are longer with a significant portion outside of the vessel and therefore are more prone to becoming entangled. However, looped shunts are more effective at bridging longer injuries or segments of missing vessel, and this design may be preferable when the vascular injury crosses a joint or an unstable fracture prone to significant motion. In these instances, the longer, looped shunt allows for motion across this defect with a lower likelihood of being dislodged. Finally, looped shunts allow visualization of arterial or venous flow and are readily assessed by continuous-wave Doppler ( Fig. 17-5 ). A unique design, the Pruitt-Inahara shunt is a side-arm port that may prove useful when angiography or drug infusion is required. Secured by proximal and distal balloons, placement of the Pruitt-Inahara may be more easily performed and avoids the need for excessive proximal and distal vessel dissection ( Fig. 17-6 ).
