Introduction
Blunt traumatic thoracic aortic injury is considered the second most common cause of death from road traffic accidents, after traumatic brain injuries [1, 2]. According to Pamley, an overwhelming majority of trauma patients die at the scene and only less than 25% reach hospital alive. Of these, 50% die within the first 24 hours of the trauma despite the treatment [3]. This poor prognosis is to a large extent a result of the frequently co-existing injuries to the head, abdomen or pelvis [4]. Sudden deceleration is thought to be the principal mechanism leading to aortic wall injury, which in nearly 90% of the cases is localised at the aortic isthmus, i.e. at the attachment of the ligamentum arteriosum [4, 5].
Currently, according to the classification proposed by the Society for Vascular Surgery (SVS) in 2011, the following types of traumatic thoracic aortic injury are distinguished: intimal tear (type I), intramural haematoma (type II), pseudoaneurysm (type III), and aortic rupture (type IV). According to many experts, conservative management, which involves strict blood pressure control and serial imaging, is recommended only for type I, while the remaining types of aortic injury (types II to IV) should be managed operatively. Until recently, operative management involved an extensive thoracotomy or sternotomy, clamping of the aorta and either suturing the site of extravasation or reconstruction using a Dacron graft [6, 7]. In 1997, Semba et al. were the first to report using stent-grafts for the treatment of traumatic thoracic aortic injuries [8]. It is now believed that the introduction of this minimally invasive technique has enabled a nearly complete replacement of the conventional repair procedure, which contributed to a considerable reduction in mortality and the risk of postoperative complications [2, 4, 6].
This paper presents the long-term outcomes of endovascular treatment of traumatic thoracic aortic pseudoaneurysm combined with a simultaneous resection of the body and tail of the pancreas due to their rupture as a result of a road traffic accident.
Case report
A 19-year-old male suffered a road traffic trauma on 6 December 2009 as a result of impact of his vehicle against a tree at a velocity of 90 km/h. Immediately after the accident the patient was conscious, haemodynamically stable and did not require resuscitation. He was admitted to a local hospital, where a computed tomography scan was performed. The scan revealed injury to the wall of the descending aorta with the formation of a pseudoaneurysm just past the left subclavian artery ostium, right pulmonary contusion, mild left-sided pneumothorax and a mediastinal haematoma. The scan also revealed pancreatic rupture at the level of the body with focal enlargement and oedema of the parenchyma, and splenic rupture. No injuries to the head, pelvis and extremities were revealed.
Within the first 24 hours of the accident the patient was transferred to our Department for further surgical management. Due to the insufficient quality of the radiographic documentation we decided to additionally order a computed tomographic angiogram (CTA) of the chest and abdomen, which confirmed the presence of a traumatic pseudoaneurysm (type III aortic injury according to SVS) measuring 36 mm in diameter at the aortic isthmus and revealed a partial extravasation of the contrast medium outside the lumen of the severed descending aorta with an accompanying mediastinal haematoma. The pseudoaneurysm originated 21 mm distal to the left subclavian artery ostium, and the aortic diameter both below and above the site of injury was 20 mm. The CTA also showed rupture of the body of the pancreas and spleen with the presence of blood in the peritoneal cavity (Fig. 1).
Figure 1. CT scan before surgery. A. Thoracic aortic pseudoaneurysm; B. Pancreatic body rupture (arrow); C. Splenic rupture (arrow)
Rycina 1. Przedoperacyjna tomografia komputerowa. A. Tętniak rzekomy aorty piersiowej; B. Pęknięcie trzonu trzustki (strzałka); C. Pęknięcie śledziony (strzałka)
We therefore decided to perform endovascular treatment of the traumatic thoracic aortic injury combined with a simultaneous laparotomy. The procedures were performed under general anaesthesia with tracheal intubation. In the first stage, the common femoral artery was exposed through an oblique inguinal incision in the right groin and obtained an arteriogram, which confirmed the previous CTA. A Zenith TX2 stent-graft 24 mm in diameter and 115 mm in length was implanted into the site of thoracic aortic injury. The final aortogram showed a complete exclusion of the traumatic descending aortic pseudoaneurysm from the systemic circulation, absence of endoleaks, and intact patency of the left subclavian artery. The next stage, which directly followed the endovascular intervention, involved a laparotomy through a transverse abdominal incision. The intraoperative findings included: intra-abdominal haemorrhage with an estimated blood loss of 1000 ml, traumatic transverse pancreatic rupture located in the central part of the body with a complete disruption of the main pancreatic duct, partial tear of the gastrocolic ligament, and an extensive splenic rupture. In addition, the omental bursa contained numerous foci of saponification (Fig. 2). In view of the above we decided to perform distal pancreatectomy and splenectomy. The remaining proximal pancreatic tissue along with the splenic artery and vein and the pancreatic duct were then ligated with non-absorbable sutures and additionally secured by covering them with a fragment of the greater omentum.
Figure 2. Intraoperative picture. The rupture of the pancreatic body and numerous foci of saponification in the omental bursa (arrow)
Rycina 2. Fotografia śródoperacyjna. Pęknięcie trzonu trzustki oraz liczne ogniska zmydlenia w torbie sieciowej (strzałka)
The postoperative course was uneventful. For eight days post-op the patient received prophylactic antibiotic therapy (imipenem and metronidazole) and total parenteral nutrition. No signs of pancreatic fistula or wound infection were observed during the postoperative period. Also, after switching from parenteral to oral nutrition, the patient did not require insulin, and on the 12th day of hospitalization he was discharged home in a good general condition. Throughout the follow-up period of nearly 5 years the patient did not require any additional interventions and at the time of writing this article continued to be normoglycaemic. Also, none of the regularly obtained CT angiograms (with the most recent one taken 6 months ago) showed any complications associated with endovascular treatment, such as stent-graft migration or endoleaks (Fig. 3 and 4).
Figure 3. CT scan 4 days after stent-graft implantation
Rycina 3. Tomografia komputerowa 4 dni po założeniu stent-graftu
Figure 4. CT scan 44 months after stent-graft implantation
Rycina 4. Tomografia komputerowa 44 miesiące po założeniu stent-graftu
Discussion
Blunt traumatic thoracic aortic injury is a dangerous, potentially life-threatening condition that requires rapid diagnosis and management. It is usually accompanied by injuries to other systems and organs, which make the prognosis worse and increase mortality. Computed tomographic angiography (CTA), which has recently replaced the traditional arteriography, is currently the method of choice for the diagnosis of aortic injuries [2, 4].
Also, since the first thoracic endovascular aortic repair (TEVAR) in 1997, there has been a fundamental change in the management of blunt traumatic aortic injuries, as stent-graft implantation has become the standard of care. It is without a doubt a much less invasive technique compared to open repair, which not only requires thoracotomy and clamping of the aorta but often also cardiopulmonary bypass and the use of a vascular prosthetic device. This is supported by the results of the meta-analysis conducted by the Society of Vascular Surgery (SVS). The meta-analysis included a total of 7768 patients with traumatic thoracic aortic injury and showed a significantly lower mortality rate in patients who underwent endovascular procedure compared to patients who underwent open repair or who were managed non-operatively (9%, 19% and 46%, respectively) [9]. The use of stent-grafts is also associated with a lower risk of spinal cord ischaemia and renal injury than open repair (3% vs. 9%, respectively, for spinal cord ischaemia, and 5% vs. 8%, respectively, for end-stage renal disease) [6, 9]. However, it must be borne in mind that the risk of TEVAR-related spinal cord ischaemia considerably increases if the stent-graft coverage of the thoracic aorta exceeds 205 mm [10, 11]. According to most authors, there is no need for routine use of spinal drainage during endovascular procedure [6]. We adopted similar tactics with our patient because the stent-graft was 115 mm in length.
According to the classification proposed by Azizzadeh et al. and the SVS guidelines, it is now believed that conservative management, which involves serial imaging and strict blood pressure control, is appropriate only in cases of traumatic intimal tear (type I). This conclusion is based on the authors’ years of experience, which clearly shows that most aortic injuries of this type heal spontaneously and do not require surgical intervention. Type II, III and IV injuries should, however, be repaired using endovascular methods [5–7]. Osgood et al., on the other hand, believe that conservative management may also be sufficient and safe in some cases of type II traumatic thoracic aortic injury as long as blood pressure control is continuously maintained and the aorta is regularly assessed by computed tomography. Their studies are, however, of limited value, as they have been conducted in a small group of patients with a short follow-up period [12].
One of the unresolved questions in the management of patients with traumatic aortic injury is the timing of surgical intervention, which should mainly depend on the patient’s general condition and presence of any concomitant multiple organ injuries [2, 9]. It is currently believed that the risk of a complete aortic rupture is the greatest within the first 24 hours after the trauma, particularly within the first 4 to 6 hours [1, 2, 5, 13]. It is therefore recommended that the aortic repair procedure should be performed preferably within the first 24 hours after the trauma [1, 6]. However, according to some reports, delayed aortic repair (within more than 24 hours after the trauma) in haemodynamically stable patients with minor injuries (Type I and II) of the aorta provides better outcomes [13–15]. The algorithm for treatment with patient after aortic injury depends on its grade, extent and severity of concomitant organ injuries. Aortic repair should be delayed in cases of minor injuries to the aortic wall and severe injuries to other organs, which require prioritised management [16].
In our patient, we decided to proceed with early (< 24 hours) TEVAR with a simultaneous laparotomy due to the leak of the contrast medium outside the lumen of the descending aorta and presence of blood in the abdominal cavity both revealed on a CT angiogram. In our opinion, this approach is safe and appropriate in this case and it has proven to be effective both in short- and long-term follow-up period.
Another controversial issue is endovascular treatment in patients aged less than 20 years. In these patients, there are significant differences in the anatomical configurations of the aorta compared to adults, such as a lower aortic diameter, which requires oversizing of the endovascular system by 10% to 20% than the actual size of the aorta and a lower curvature of the aortic arch, which may result in occurrence of endoleaks or even stent-graft collapse [2, 4, 5, 11, 17].
Blunt traumatic pancreatic injuries are relatively rare and account for less than 2% of all traumatic abdominal injuries [18]. Due to the retroperitoneal location of the pancreas in the proximity of the lumbar spine, the body or the tail of the pancreas are most commonly injured [19]. In many cases, no clinical manifestations to suggest this type of injury are present. The most important determinants of appropriate management of traumatic pancreatic injuries are the extent and severity of pancreatic duct damage [19, 20]. According to Degiannis et al., most traumatic injuries of the pancreas can be managed with external drainage. Injuries to the body or tail with disruption of the pancreatic duct usually require partial pancreatectomy with splenectomy. Injuries to the head of the pancreas my successfully be managed with external drainage, even if the pancreatic duct is injured [19].
Surgical interventions involving the pancreas are often associated with local and systemic complications, which negatively affect the final outcome of treatment. Pancreatic fistula is the most common described complication, which occurs in more than 25% of the patients undergoing pancreatic surgery [21]. Most fistulas, however, close spontaneously without additional intervention. It is recommended to cover the remnant of pancreatic tissue with greater omentum and initiate total parenteral nutrition early [22, 23]. This way of treatment proved to be very effective also in our patient in the five-year observation period.
Conclusions
1. Endovascular repair of traumatic thoracic aortic injury combined with simultaneous distal resection of pancreas due to its rupture proved to be an effective and safe management option, also in the long-term follow-up period.
2. The appropriate management and the optimal sequence of treatment for blunt traumatic aortic injury mainly depends on the patient’s general condition and concomitance of other organs injuries.