Introduction

Massive hemorrhage is the most common cause of shock in trauma patients. Retroperitoneal space is one of the major bleeding cavities, in which hemorrhage is most frequently associated with pelvic fracture [1, 2]. Lumbar artery injury (LAI) can also lead to upper retroperitoneal hemorrhage [3, 4], which can be a cause of shock leading to life-threatening condition.

Lumbar artery injury associated with lumbar spinal fracture/dislocation is relatively rare [3–6]. Once retroperitoneal hemorrhage is caused by lumbar artery injury, surgery often fails to identify bleeding sources and can cause further bleeding, limiting its use [4, 6–8]. Transcatheter arterial embolization (TAE) has been demonstrated to be safe and effective method for immediate control of active extravasation, as well as to prevent future hemorrhage from an injured lumbar artery [4, 6–9].

The Adamkiewicz artery (AKA) supplies blood to the anterior spinal artery and often bifurcates from a lumbar or an intercostal artery at the thoracolumbar junction, where spinal injury most commonly occurs [10–12]. Thus, embolization or ligation of the lumbar artery has a risk of spinal cord ischemia [3, 4, 6, 13]. However, in emergency TAE for retroperitoneal hemorrhagic patients, hemostasis has priority and blood supply to the AKA is not frequently confirmed, which may result in paralysis after treatment [3, 4, 6, 14].

We describe here a case of lumbar spine injury with lumbar artery injury from which the AKA was bifurcated. In this case, the collateral circulation to the AKA was carefully confirmed by selective angiography and emergency TAE was successfully conducted not only to obtain hemostasis but also to prevent spinal cord ischemia.

Case report

A 58-year-old man was pinned under about 300-kg steel container that fell on his back at a parcel delivery service distribution center. He was transported to our hospital complaining of back pain 40 min after the accident. On arrival, he presented with hemorrhagic shock. A subcutaneous hematoma was noted in the thoracolumbar junction. Neurological findings were normal.

Computed tomography (CT) demonstrated L1–2 type C injury according to the Magerl classification [15] (Fig. 1), and the left psoas major muscle swelling with extravasation of contrast medium, which suspected lumbar artery injury (Fig. 2). No other lesions related to hemodynamic instability were detected. Transfusion of red cell concentrate (4 units) was given and emergency angiography was performed.

Fig. 1
figure 1

Computed tomography of the lumbar spine demonstrated L1–2 flexion-distraction injury

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Fig. 2
figure 2

Contrast-enhanced CT demonstrated swelling of the left psoas major muscle and extravasation of the contrast medium (arrow)

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A large amount extravasation of contrast medium was demonstrated from the proximal part of the left 2nd lumbar artery. Likewise, the AKA originated from the distal part of this artery (Fig. 3). Intra-arterial infusion of 1 % lidocaine into the proximal part of the left 2nd lumbar artery induced paralysis of both legs, suggesting the embolization of this artery may possibly cause spinal cord ischemia. Accordingly, the proximal part of this artery could not be chosen as a site of embolization.

Fig. 3
figure 3

Angiography of the left 2nd lumbar artery trunk demonstrated extravasation of contrast medium from the proximal part of the artery (arrow). The Adamkiewicz artery was originated from the distal part of the artery (white arrow)

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Subsequent selective angiography of the left 1st lumbar artery depicted collateral circulation to the left 2nd lumbar artery without arterial damages (Fig. 4). Therefore, embolization of the proximal part of left 2nd lumbar artery was performed. After the embolization, the left 1st lumbar artery was confirmed to have patency of the AKA (Fig. 5). Selective angiography of the right 2nd lumbar artery showed multiple extravasations (Fig. 6). After this artery was embolized, circulation had become stable without necessity of additional blood transfusion. No paralysis occurred.

Fig. 4
figure 4

Angiography of the left 1st lumbar artery depicted the Adamkiewicz artery (white arrow) via collateral circulation

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Fig. 5
figure 5

Post-embolization angiography using embolization coils of the left 2nd lumbar artery demonstrated patency of the Adamkiewicz artery (white arrow)

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Fig. 6
figure 6

Angiography of the right 2nd lumbar artery demonstrated multiple extravasations (arrow)

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On the 7th day after injury when the general condition was stabilized, L2 spine-shortening osteotomy [16] using T12–L3 pedicle screw and rod system were conducted. The patient had a favorable postoperative course and was referred to a hospital for rehabilitation 2 weeks after surgery. On a follow-up examination 2 years after surgery, there were no subjective symptoms of back pain, and no abnormal neurological findings. Plain X-rays revealed complete bone union (Fig. 7).

Fig. 7
figure 7

Posteroanterior (a) and lateral (b) plain radiographs of the lumbar spine 2 years after the surgery revealed bone union

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Discussion

Lumbar artery injury occurs rarely, and is caused by penetrating, blunt trauma and iatrogenic injury [3–5, 17]. Lumbar arteries are less mobile and thus, they might be lacerated by the mobile aorta in high-energy trauma [3, 18]. LAI associated with spinal fracture/dislocation can be life-threatening when it is responsible for massive hemorrhage [3–6]. Since the retroperitoneal space is abundant in blood vessels, surgical hemostasis is very invasive and difficult, particularly, in cases of severe hemorrhage associated with coagulopathy. Therefore, TAE is the treatment of choice of lumbar artery injury [4, 6–9].

The AKA usually bifurcates from one of the T8–L2 intercostal or lumbar arteries on the left side, and nourishes the lower part of the spinal cord [10–12]. Since spinal injuries frequently occur in the thoracolumbar junction, the intercostal or lumbar arteries from which the AKA bifurcates can be injured. In addition, once the artery from which the AKA originates is embolized at the proximal part of the AKA bifurcation, severe paraplegia may be induced [3, 4, 6, 14]. Thus, before embolization of these vessels, the relationship between the intercostal or lumbar arteries and the AKA should be carefully confirmed [4]. The test for paraplegia by administration of a local anesthetic before TAE [19] is useful but it is actually insignificant in patients with disturbance of consciousness or serious complication of spinal cord injury [3].

In the present case, the main source of hemorrhage was the retroperitoneal space, as indicated by contrast-enhanced CT, and the main cause of bleeding was strongly suspected to be the bilateral 2nd lumbar arterial injuries, as indicated by angiography. Since the AKA was found to arise from the left 2nd lumbar artery, selective angiography was performed on the surrounding lumbar arteries to evaluate the collateral circulation. Fortunately, collateral circulation to the AKA was confirmed to come from the left 1st lumbar artery. Thus, the left 2nd lumbar artery could be embolized and massive hemorrhage could be controlled successfully.

Conclusions

Close attention must be paid to LAI in the management of patients with lumbar spine injury. Once the LAI is found, TAE can be the choice of the treatment with careful attention to the AKA. If the AKA bifurcates from the injured lumbar artery, selective angiography of the adjoining lumbar arteries to evaluate collateral circulation before execution of TAE should be performed while maintaining blood supply to the AKA.