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Nonoperative Management of Pediatric Aortic Injury with Seat Belt Syndrome
Nonoperative Management of Pediatric Aortic Injury with Seat Belt Syndrome Dan W. Parrish,1 Amanda Barnhorst,2 Katarzyna Trebska-McGowan,1 Michael Amendola,1 and Jeffrey H. Haynes,1,3 Richmond, Virginia
‘‘Seat belt syndrome’’ was first described by Garret and Braunstein in 1962. The syndrome involves skin and abdominal wall ecchymosis (seat belt sign) intra-abdominal solid organ and visceral injuries, as well as Chance fractures (compression and/or wedging deformity of the anterior portion of the vertebral body with disruption or fracture of the posterior elements, generally at L1eL3). We present a case of a 12-year-old male involved in a high-speed motor vehicle collision wearing only a lap belt resulting in seat belt syndrome, with disruption of the abdominal wall, mesenteric avulsion with multiple intestinal perforations, abdominal aortic dissection, and an L2 Chance fracture with cord transection. Intraoperative decision making is outlined with this scenario of complex injuries, and the literature of seat belt syndrome associated with blunt aortic injuries and its management is reviewed.
‘‘Just as the use of penicillin has led to numerous examples of penicillin allergy or anaphylactic reactions, so in the use of seat belts, many physicians and investigators feared that the belt itself might contribute to many untoward situations and injuries.’’ John Garrett and Dr. Paul Braunstein, 1962.1 The seat belt was first introduced in 1964 as a standard equipment in North American vehicles to prevent death and injury. Although this was one of the most significant advances in automobile safety, it also created a new pattern of injuries. In 1962, ‘‘seat belt syndrome’’ was described as a constellation of injuries associated with flexion distraction
injuries to the abdomen and spine sustained during moderate-to-highespeed motor vehicle collisions while wearing a seat belt. Aortic injury accompanying abdominal blunt trauma is rare and was not originally described as part of seat belt syndrome. In 1979, Dajee et al.2 first described the ‘‘seat belt aorta’’ as a variety of aortic injuries experienced from 2- and 3-point restraint systems, including dissection and thrombosis of the abdominal aorta. We describe a case of seat belt syndrome with multiple intra-abdominal injuries associated with blunt aortic injury and review the management and pertinent literature.
CASE REPORT Funding: No financial support was provided for this study. 1
Department of Surgery, Virginia Commonwealth University, Richmond, VA. 2 Department of Emergency Medicine, Virginia Commonwealth University, Richmond, VA. 3 Children’s Hospital of Richmond, Virginia Commonwealth University Health System, Richmond, VA.
Correspondence to: Jeffrey H. Haynes, MD, Department of Surgery, Virginia Commonwealth University, PO Box 980015, Richmond, VA 23298-0015, USA; E-mail: [email protected] Ann Vasc Surg 2015; 29: 1316.e1–1316.e6 http://dx.doi.org/10.1016/j.avsg.2015.02.019 Ó 2015 Elsevier Inc. All rights reserved. Manuscript received: August 11, 2014; manuscript accepted: February 1, 2015; published online: May 28, 2015.
A 12-year-old male was in a high-speed motor vehicle collision with sudden deceleration as a rear-seat passenger restrained only by his lap belt. At the scene, the patient was found to be hypotensive and unresponsive. En route to a community hospital, the patient experienced 2 events of asystole with return of spontaneous circulation after administration of epinephrine and 2 L of crystalloids. His Glasgow Coma Scale score was 6, and he was intubated for airway protection. After initial stabilization, including 3 units of packed red blood cells, he was transported by air to our level 1 Pediatric Trauma Center. He arrived fully immobilized and hemodynamically unstable with blood pressure of 70/40 mm Hg and heart rate of 150. Physical examination was limited because of the patient’s 1316.e1
1316.e2 Case reports
neurologic state; however, he was making spontaneous arm and mouth movements with appropriate response to painful stimuli in upper extremities. No lower extremity movement or response was noted either at the scene or at the hospital. His head, neck, and chest appeared atraumatic. He required significant volume resuscitation in the emergency department to maintain his blood pressure. A focused assessment with sonography for trauma (FAST) examination was negative for fluid in chest or abdomen, but it was thought that this could be falsely negative due to his continued transient stability. Physical examination revealed a soft and distended abdomen with a ‘‘seat belt sign,’’ swelling in the lower thoracic area, and ecchymosis involving lower abdominal musculature and lumbar spine. The pelvis was stable. He had palpable femoral, posterior tibial, and dorsalis pedis pulses bilaterally. Because the patient was transiently stable hemodynamically, after he initially responded to the crystalloid administration and in light of the negative FAST, computerized tomography (CT) scans of the head, chest, and abdomen were performed (Fig. 1). Imaging revealed ruptured abdominal wall musculature, active extravasation from the mesentery, intraperitoneal fluid collection, and a crescent of intraluminal low attenuation within the aorta consistent with dissection flap. This aortic injury originated 2.2 cm above the aortic bifurcation. The aortic diameter was approximately 10 mm proximal to the dissection flap and approximately 14 mm at the level of the injury. In addition, lumbar spine images revealed an L2 Chance fracture. An emergent exploratory laparotomy was performed; a large hemoperitoneum was present. Approximately 60% of the jejunum and ileum were avulsed from the mesentery, in addition to a 4-cm segment of the descending colon. Mesenteric bleeding was controlled, and the injured bowel was resected with the remaining bowel left in discontinuity as a part of a damage control strategy. Vascular surgery intraoperative consult was obtained to address the aortic injury. The aorta was examined, and no surrounding hematoma or adventitial injuries were seen. Doppler examination confirmed triphasic flows above and below the area of concern on CT. The patient’s abdominal wound was left open and covered with a wound vacuum assisted closure (VAC) device, and the patient was transported to the pediatric intensive care unit for further resuscitation and warming. Postoperatively, the patient did not require vasopressor support or transfusions. He had a stable distal pulse examination with normal Doppler signals. The nonoperative management of this aortic injury included blood pressure control to maintain a systolic pressure below 120 mm Hg, serial hemoglobin measures, and distal pulse examinations. He returned to the operating room 2 days later for restoration of small bowel continuity, creation of colostomy, and repair of complex abdominal wall injury. Initial attempts at primary muscular repair were made but dehisced, and the abdomen was then closed with SurgisisÒ (Cook Biotech, West Lafayette, IN) mesh 8 days after his initial presentation. A repeat CT angiogram
Annals of Vascular Surgery
(CTA) on postoperative day 7 demonstrated improved aortic wall hematoma and unchanged degree of dissection. The patient’s vascular examination remained unchanged, and nonoperative management for the aortic injury was continued. His abdominal defect previously reconstructed with Surgisis was covered with a skin graft 10 weeks later. The repair of his spinal fractures was delayed because of abscess formation at the site of the injury but was ultimately stabilized. He completed inpatient rehabilitation with complete T8 paraplegia and was discharged home on hospital day 89. A follow up CTA 1 month after initial presentation revealed no hematoma and no dissection flap. Additional CTAs and an arterial duplex of the aorta were performed at 4, 8, and 12 months. This imaging, Figure 2, demonstrated a slight enlargement of the midabdominal aorta to 16 mm with stable pseudoaneurysm at 4, 8, and 12 months.
DISCUSSION Seat belt syndrome refers to a unique set of injuries to the lumbar spine and visceral organs sustained during motor vehicle collisions. A constellation of findings include skin and abdominal wall ecchymosis (seat belt sign), intra-abdominal solid organ and visceral injuries, and Chance fractures (compression and/or wedging deformity of the anterior portion of the vertebral body with disruption or fracture of the posterior elements, generally at L1eL3).1 Vascular injury is uncommon in blunt pediatric trauma; 0.6% of all pediatric trauma patients have any form of vascular injury; 25% of these affect abdominal vasculature.3 Two large reviews of pediatric trauma databases reported the rate of aortic injury in blunt abdominal trauma to be around 0.1%.4,5 The mechanism of injury involves both direct and indirect forces. The direct forces crush the aorta between the vertebral column and the seat belt, which is the mechanism responsible for the constellation of injuries in seat belt syndrome. In addition, the elongating of the aorta from the pressure of the decelerating column of blood and changes in the intraluminal pressure may add to the injury.6 Small asymptomatic intimal flaps are often followed conservatively with repeat imaging secondary to a high rate of spontaneous resolution, whereas circumferential flaps can lead to more serious sequelae including mesenteric or spinal cord ischemia.7 Blunt abdominal aorta injuries may be diagnosed in a variety of ways depending on the presentation. The patients may range from asymptomatic to mild abdominal pain to those with profound hemodynamic instability. Choit et al. described 12 pediatric
Vol. 29, No. 6, August 2015
Case reports 1316.e3
Fig. 1. Emergency department trauma protocol intravenous (IV) contrast CT examination. (AeC) Serial axial images through the aorta at the level of injury show irregular lumen and aorta walls. Arrow at (A) and (B) denote extraluminal IV contrast. (D) Sagittal image denotes the full extent
of aortic injury. There are several locules of free air in addition to the chance fracture at L1/L2. (E) Paracoronal reformated image along the plane of the aorta captures the normal appearing lumen proximal and distal to the injury.
patients who were involved in motor vehicle collisions as restrained passengers who experienced concomitant injuries of lumbar spine, visceral organs, and abdominal aorta. The most common early symptoms on presentation were back and abdominal pain, with changes in peripheral pulses, bruit, or a pulsatile abdominal mass representing late findings. These investigators cautioned to maintain a high index of suspicion when pediatric patients present with a similar injury pattern after motor vehicle accident. They found that 2 of 12 patients were completely asymptomatic with injuries
only identified on abdominal CT scans.8 Patients with signs of hemodynamic instability are likely to be taken for emergent laparotomy. In these cases, the extent of vascular injury might be unknown until definitive imaging is possible. In stable patients, spiral contrast enhanced CT scans has replaced angiography as the gold standard imaging modality.6 In the patients who could not undergo preoperative imaging, intraoperative ultrasound is a useful modality to help guide decision making before embarking on complex aortic repair in the setting of multisystem trauma. Color or flow and gray scale
1316.e4 Case reports
Annals of Vascular Surgery
Fig. 2. Sagittal images from (A) CTA obtained 1 month after acute injury and (B) routine intravenous contrast CT 4 months after injury highlight stable aortic appearance. In the interval from (A) to (B) the patient
underwent posterior lumbar fusion from T12 to L3. Hardware is partially visualized with significant improved alignment at L1/L2.
duplex imaging can also aid in the operative management of aortic repair with guiding surgeons on the assessment of viable aortic margins in the setting of aortic repair.9 There is no consensus on the best management of abdominal aorta injuries in children. Most data in the literature come from case reports and case series, many of which deal with traumatic injuries of thoracic aorta.10e13 Options, as in adults, include open surgical repair, endovascular intervention, or observation and conservative management with medical therapy. Anderson et al. published a case series of 11 pediatric patients who experienced aortic injuries as a result of blunt trauma. Four of these patients had abdominal aorta disruption. All these cases resulted from motor vehicle crashes with all victims wearing seat belts. The injuries were diagnosed by CT; 3 of them were classified as intimal flap tears and 1 was a dissection of infrarenal aorta. Three patients were managed nonoperatively; one child with intimal flap tear required primary repair due to abnormal ankle brachial index measurement and diminished distal pulses. No complications were noted in any of the abdominal aortic injuries treated with conservative measures.14 McCarthy et al. published a review of 17 cases of pediatric traumatic abdominal aortic injuries. All
the injuries were managed operatively. One patient died during the surgery, before repair of his aorta; 6 had primary repair; and 9 injuries were repaired with a variety of grafts. Injuries in 5 patients were not repaired on initial presentation, and they required delayed repair of pseudoaneurysm within 7 months of trauma.15 One question that remains in the pediatric population is the appropriateness of definitive repair at an age when further aortic growth might complicate a durable reconstruction. This has lead some investigators to recommend the use of autografts of the internal iliac artery, external iliac artery, or superficial femoral artery with prosthetic donor site reconstructions as needed.16 The present case highlights important aspects of pediatric trauma patient care; in particular, joint decision making between pediatric surgery and vascular surgery to establish management priorities of this rare presentation. This discussion began at the patient’s initial laparotomy with the decision to delay aortic repair in the setting of other more pressing traumatic injuries. Despite the intimal injury and the intramural hematoma, formal aortic repair was agreed to be unnecessary at initial presentation in the setting of damage control principles of hemorrhage and intestinal contamination control. Aside from observation that the
Vol. 29, No. 6, August 2015
patient had adequate perfusion to the lower extremities, exploration and the use of intraoperative ultrasound facilitated the decision to pursue conservative management approach with close observation and intervention only if an emergent situation arose. Embarking on a definitive repair at the time of the initial operation, whether aortic or visceral, would have exposed the patient’s arterial repair to a contaminated operative field. Although it has been shown in adults that polytetraflourethylene graft placement in contaminated fields may not result in increased infection rates,17 potential infection risk influences choice of repair toward an autologous conduit in such settings. In addition, the patient’s tenuous hemodynamic status supercedes definitive aortic surgery in terms of repair and potential autograft harvest. Because the patient’s initial operation was in a damage control scenario, the relative hypotension, potential coagulopathy, and hypothermia would place any definitive repair at risk for failure. The patient’s age and size were also in consideration. The patient presented as a 5-ft tall healthy 12-year old weighing 130 lbs. The placement of a graft in a child who will continue to grow has largely unknown long-term consequences. Bardain et al. believe that using synthetic grafts for vascular repair in patients with further growth potential should be avoided because of the fixed size of the aortic repair. Most likely, such patients would require replacement or revision of their graft at a future date. If a vascular graft has to be used in a pediatric patient, it should be larger than necessary to account for future growth.9 Other conduits such as internal iliac artery would have been time consuming and not advisable at the point of initial exploration, and the use of saphenous vein may result in a significant rate of aneurysmal degeneration.15 None of these seemed necessary once the present patient was stabilized. Moreover, in our patient, who is paraplegic, the need for definitive repair is in question secondary to his future limited lower extremity utilization. In conclusion, based on our patient’s condition and the literature review, we believe nonoperative management was the best course of care for our patient. The intraoperative examination with Doppler ultrasound of his aorta, along with his stable and unchanging peripheral pulse examination, allowed us to primarily concern ourselves with the resuscitation and repair of his other injuries rather than having to add an aortic repair to his list of operations. We conclude that, in the setting of hemodynamic instability with intra-
Case reports 1316.e5
abdominal injuries, a patient who has an easily examined, stable, and unchanging pulse examination after blunt injury to the abdominal aorta can undergo nonoperative management of the aortic injury. Prospectively, nonoperative management is further based on the continued monitoring of our patient’s aortic injury for increasing dissection and/or aneurysmal formation. Ultrasonography is appealing because of no exposure to radiation and its ability to demonstrate turbulent flow if present. In addition, the use of the same imaging technique in subsequent examinations will simplify comparison between the studies.18 At present, the patient will be followed with yearly duplex examinations for interval changes and CTA only if additional pathology develops to minimize the effects of ionizing radiation.
REFERENCES 1. Garrett JW, Braunstein PW. The seat belt syndrome. J Trauma 1962;2:220e38. 2. Dajee H, Richardson IW, Iype MO. Seat belt aorta: acute dissection and thrombosis of the abdominal aorta. Surgery 1979;85:263e7. 3. Barmparas G, Inaba K, Talving P, et al. Pediatric vs adult vascular trauma: a National Trauma Databank review. J Pediatr Surg 2010;45:1404e12. 4. Heckman SR, Trooskin SZ, Burd RS. Risk factors for blunt thoracic aortic injury in children. J Pediatr Surg 2005;40: 98e102. 5. Hamner CE, Groner JI, Caniano DA, et al. Blunt intraabdominal arterial injury in pediatric trauma patients: injury distribution and markers of outcome. J Pediatr Surg 2008;43:916e23. 6. Freni L, Barbetta I, Mazzaccaro D, et al. Seat belt injuries of the abdominal aorta in adultsecase report and literature review. Vasc Endovascular Surg 2013;47:138e47. 7. Starnes BW, Lundgren RS, Gunn M, et al. A new classification scheme for treating blunt aortic injury. J Vasc Surg 2012;55:47e54. 8. Choit RL, Tredwell SJ, Leblanc JG, et al. Abdominal aortic injuries associated with chance fractures in pediatric patients. J Pediatr Surg 2006;41:1184e90. 9. Bairdain S, Modi BP, Kim HB, et al. Pediatric blunt abdominal aortic injury and the use of intra-operative aortic ultrasound for surgical decision making. J Pediatr Surg 2013;48:1584e7. 10. Takach TJ, Anstadt MP, Moore HV. Pediatric aortic disruption. Tex Heart J 2005;32:16e20. 11. Karmy-Jones R, Hoffer E, Meissner M, Bloch RD. Management of traumatic rupture of the thoracic aorta in pediatric patients. Ann Thorac Surg 2003;75:1513e7. 12. Gunabushanam V, Mishra N, Calderin J, et al. Endovascular stenting of blunt thoracic aortic injury in an 11-year-old. J Pediatr Surg 2010;45:E15e8. 13. Milas ZL, Milner R, Chaikoff E, et al. Endograft stenting in the adolescent population for traumatic aortic injuries. J Pediatr Surg 2006;41:e27e30.
1316.e6 Case reports
14. Anderson SA, Day M, Chen MK, et al. Traumatic aortic injuries in the pediatric population. J Pediatr Surg 2008;43:1077e81. 15. McCarthy MC, Price SW, Rundell WK, et al. Pediatric blunt abdominal aortic injuries: case report and review of the literature. J Trauma 2007;63:1383e7. 16. Rajagopalan S, Dean SM, Mohler ER, Mukherjee D. Manual of Vascular Diseases. Riverwoods, IL: Wolters Kluwer Health, 2011.
Annals of Vascular Surgery
17. Shah DM, Leather RP, Corson JD, Karmody AM. Polytetrafluoroethylene grafts in the rapid reconstruction of acute contaminated peripheral vascular injuries. Am J Surg 1984;148:229e33. 18. Khanna PC, Rothenbach P, Guzzetta PC, Bulas DI. Lap-belt syndrome: management of aortic intimal dissection in a 7-year-old child with a constellation of injuries. Pediatr Radiol 2007;37:87e90.
‘‘Seat belt syndrome’’ was first described by Garret and Braunstein in 1962. The syndrome involves skin and abdominal wall ecchymosis (seat belt sign) intra-abdominal solid organ and visceral injuries, as well as Chance fractures (compression and/or wedging deformity of the anterior portion of the vertebral body with disruption or fracture of the posterior elements, generally at L1eL3). We present a case of a 12-year-old male involved in a high-speed motor vehicle collision wearing only a lap belt resulting in seat belt syndrome, with disruption of the abdominal wall, mesenteric avulsion with multiple intestinal perforations, abdominal aortic dissection, and an L2 Chance fracture with cord transection. Intraoperative decision making is outlined with this scenario of complex injuries, and the literature of seat belt syndrome associated with blunt aortic injuries and its management is reviewed.
‘‘Just as the use of penicillin has led to numerous examples of penicillin allergy or anaphylactic reactions, so in the use of seat belts, many physicians and investigators feared that the belt itself might contribute to many untoward situations and injuries.’’ John Garrett and Dr. Paul Braunstein, 1962.1 The seat belt was first introduced in 1964 as a standard equipment in North American vehicles to prevent death and injury. Although this was one of the most significant advances in automobile safety, it also created a new pattern of injuries. In 1962, ‘‘seat belt syndrome’’ was described as a constellation of injuries associated with flexion distraction
injuries to the abdomen and spine sustained during moderate-to-highespeed motor vehicle collisions while wearing a seat belt. Aortic injury accompanying abdominal blunt trauma is rare and was not originally described as part of seat belt syndrome. In 1979, Dajee et al.2 first described the ‘‘seat belt aorta’’ as a variety of aortic injuries experienced from 2- and 3-point restraint systems, including dissection and thrombosis of the abdominal aorta. We describe a case of seat belt syndrome with multiple intra-abdominal injuries associated with blunt aortic injury and review the management and pertinent literature.
CASE REPORT Funding: No financial support was provided for this study. 1
Department of Surgery, Virginia Commonwealth University, Richmond, VA. 2 Department of Emergency Medicine, Virginia Commonwealth University, Richmond, VA. 3 Children’s Hospital of Richmond, Virginia Commonwealth University Health System, Richmond, VA.
Correspondence to: Jeffrey H. Haynes, MD, Department of Surgery, Virginia Commonwealth University, PO Box 980015, Richmond, VA 23298-0015, USA; E-mail: [email protected] Ann Vasc Surg 2015; 29: 1316.e1–1316.e6 http://dx.doi.org/10.1016/j.avsg.2015.02.019 Ó 2015 Elsevier Inc. All rights reserved. Manuscript received: August 11, 2014; manuscript accepted: February 1, 2015; published online: May 28, 2015.
A 12-year-old male was in a high-speed motor vehicle collision with sudden deceleration as a rear-seat passenger restrained only by his lap belt. At the scene, the patient was found to be hypotensive and unresponsive. En route to a community hospital, the patient experienced 2 events of asystole with return of spontaneous circulation after administration of epinephrine and 2 L of crystalloids. His Glasgow Coma Scale score was 6, and he was intubated for airway protection. After initial stabilization, including 3 units of packed red blood cells, he was transported by air to our level 1 Pediatric Trauma Center. He arrived fully immobilized and hemodynamically unstable with blood pressure of 70/40 mm Hg and heart rate of 150. Physical examination was limited because of the patient’s 1316.e1
1316.e2 Case reports
neurologic state; however, he was making spontaneous arm and mouth movements with appropriate response to painful stimuli in upper extremities. No lower extremity movement or response was noted either at the scene or at the hospital. His head, neck, and chest appeared atraumatic. He required significant volume resuscitation in the emergency department to maintain his blood pressure. A focused assessment with sonography for trauma (FAST) examination was negative for fluid in chest or abdomen, but it was thought that this could be falsely negative due to his continued transient stability. Physical examination revealed a soft and distended abdomen with a ‘‘seat belt sign,’’ swelling in the lower thoracic area, and ecchymosis involving lower abdominal musculature and lumbar spine. The pelvis was stable. He had palpable femoral, posterior tibial, and dorsalis pedis pulses bilaterally. Because the patient was transiently stable hemodynamically, after he initially responded to the crystalloid administration and in light of the negative FAST, computerized tomography (CT) scans of the head, chest, and abdomen were performed (Fig. 1). Imaging revealed ruptured abdominal wall musculature, active extravasation from the mesentery, intraperitoneal fluid collection, and a crescent of intraluminal low attenuation within the aorta consistent with dissection flap. This aortic injury originated 2.2 cm above the aortic bifurcation. The aortic diameter was approximately 10 mm proximal to the dissection flap and approximately 14 mm at the level of the injury. In addition, lumbar spine images revealed an L2 Chance fracture. An emergent exploratory laparotomy was performed; a large hemoperitoneum was present. Approximately 60% of the jejunum and ileum were avulsed from the mesentery, in addition to a 4-cm segment of the descending colon. Mesenteric bleeding was controlled, and the injured bowel was resected with the remaining bowel left in discontinuity as a part of a damage control strategy. Vascular surgery intraoperative consult was obtained to address the aortic injury. The aorta was examined, and no surrounding hematoma or adventitial injuries were seen. Doppler examination confirmed triphasic flows above and below the area of concern on CT. The patient’s abdominal wound was left open and covered with a wound vacuum assisted closure (VAC) device, and the patient was transported to the pediatric intensive care unit for further resuscitation and warming. Postoperatively, the patient did not require vasopressor support or transfusions. He had a stable distal pulse examination with normal Doppler signals. The nonoperative management of this aortic injury included blood pressure control to maintain a systolic pressure below 120 mm Hg, serial hemoglobin measures, and distal pulse examinations. He returned to the operating room 2 days later for restoration of small bowel continuity, creation of colostomy, and repair of complex abdominal wall injury. Initial attempts at primary muscular repair were made but dehisced, and the abdomen was then closed with SurgisisÒ (Cook Biotech, West Lafayette, IN) mesh 8 days after his initial presentation. A repeat CT angiogram
Annals of Vascular Surgery
(CTA) on postoperative day 7 demonstrated improved aortic wall hematoma and unchanged degree of dissection. The patient’s vascular examination remained unchanged, and nonoperative management for the aortic injury was continued. His abdominal defect previously reconstructed with Surgisis was covered with a skin graft 10 weeks later. The repair of his spinal fractures was delayed because of abscess formation at the site of the injury but was ultimately stabilized. He completed inpatient rehabilitation with complete T8 paraplegia and was discharged home on hospital day 89. A follow up CTA 1 month after initial presentation revealed no hematoma and no dissection flap. Additional CTAs and an arterial duplex of the aorta were performed at 4, 8, and 12 months. This imaging, Figure 2, demonstrated a slight enlargement of the midabdominal aorta to 16 mm with stable pseudoaneurysm at 4, 8, and 12 months.
DISCUSSION Seat belt syndrome refers to a unique set of injuries to the lumbar spine and visceral organs sustained during motor vehicle collisions. A constellation of findings include skin and abdominal wall ecchymosis (seat belt sign), intra-abdominal solid organ and visceral injuries, and Chance fractures (compression and/or wedging deformity of the anterior portion of the vertebral body with disruption or fracture of the posterior elements, generally at L1eL3).1 Vascular injury is uncommon in blunt pediatric trauma; 0.6% of all pediatric trauma patients have any form of vascular injury; 25% of these affect abdominal vasculature.3 Two large reviews of pediatric trauma databases reported the rate of aortic injury in blunt abdominal trauma to be around 0.1%.4,5 The mechanism of injury involves both direct and indirect forces. The direct forces crush the aorta between the vertebral column and the seat belt, which is the mechanism responsible for the constellation of injuries in seat belt syndrome. In addition, the elongating of the aorta from the pressure of the decelerating column of blood and changes in the intraluminal pressure may add to the injury.6 Small asymptomatic intimal flaps are often followed conservatively with repeat imaging secondary to a high rate of spontaneous resolution, whereas circumferential flaps can lead to more serious sequelae including mesenteric or spinal cord ischemia.7 Blunt abdominal aorta injuries may be diagnosed in a variety of ways depending on the presentation. The patients may range from asymptomatic to mild abdominal pain to those with profound hemodynamic instability. Choit et al. described 12 pediatric
Vol. 29, No. 6, August 2015
Case reports 1316.e3
Fig. 1. Emergency department trauma protocol intravenous (IV) contrast CT examination. (AeC) Serial axial images through the aorta at the level of injury show irregular lumen and aorta walls. Arrow at (A) and (B) denote extraluminal IV contrast. (D) Sagittal image denotes the full extent
of aortic injury. There are several locules of free air in addition to the chance fracture at L1/L2. (E) Paracoronal reformated image along the plane of the aorta captures the normal appearing lumen proximal and distal to the injury.
patients who were involved in motor vehicle collisions as restrained passengers who experienced concomitant injuries of lumbar spine, visceral organs, and abdominal aorta. The most common early symptoms on presentation were back and abdominal pain, with changes in peripheral pulses, bruit, or a pulsatile abdominal mass representing late findings. These investigators cautioned to maintain a high index of suspicion when pediatric patients present with a similar injury pattern after motor vehicle accident. They found that 2 of 12 patients were completely asymptomatic with injuries
only identified on abdominal CT scans.8 Patients with signs of hemodynamic instability are likely to be taken for emergent laparotomy. In these cases, the extent of vascular injury might be unknown until definitive imaging is possible. In stable patients, spiral contrast enhanced CT scans has replaced angiography as the gold standard imaging modality.6 In the patients who could not undergo preoperative imaging, intraoperative ultrasound is a useful modality to help guide decision making before embarking on complex aortic repair in the setting of multisystem trauma. Color or flow and gray scale
1316.e4 Case reports
Annals of Vascular Surgery
Fig. 2. Sagittal images from (A) CTA obtained 1 month after acute injury and (B) routine intravenous contrast CT 4 months after injury highlight stable aortic appearance. In the interval from (A) to (B) the patient
underwent posterior lumbar fusion from T12 to L3. Hardware is partially visualized with significant improved alignment at L1/L2.
duplex imaging can also aid in the operative management of aortic repair with guiding surgeons on the assessment of viable aortic margins in the setting of aortic repair.9 There is no consensus on the best management of abdominal aorta injuries in children. Most data in the literature come from case reports and case series, many of which deal with traumatic injuries of thoracic aorta.10e13 Options, as in adults, include open surgical repair, endovascular intervention, or observation and conservative management with medical therapy. Anderson et al. published a case series of 11 pediatric patients who experienced aortic injuries as a result of blunt trauma. Four of these patients had abdominal aorta disruption. All these cases resulted from motor vehicle crashes with all victims wearing seat belts. The injuries were diagnosed by CT; 3 of them were classified as intimal flap tears and 1 was a dissection of infrarenal aorta. Three patients were managed nonoperatively; one child with intimal flap tear required primary repair due to abnormal ankle brachial index measurement and diminished distal pulses. No complications were noted in any of the abdominal aortic injuries treated with conservative measures.14 McCarthy et al. published a review of 17 cases of pediatric traumatic abdominal aortic injuries. All
the injuries were managed operatively. One patient died during the surgery, before repair of his aorta; 6 had primary repair; and 9 injuries were repaired with a variety of grafts. Injuries in 5 patients were not repaired on initial presentation, and they required delayed repair of pseudoaneurysm within 7 months of trauma.15 One question that remains in the pediatric population is the appropriateness of definitive repair at an age when further aortic growth might complicate a durable reconstruction. This has lead some investigators to recommend the use of autografts of the internal iliac artery, external iliac artery, or superficial femoral artery with prosthetic donor site reconstructions as needed.16 The present case highlights important aspects of pediatric trauma patient care; in particular, joint decision making between pediatric surgery and vascular surgery to establish management priorities of this rare presentation. This discussion began at the patient’s initial laparotomy with the decision to delay aortic repair in the setting of other more pressing traumatic injuries. Despite the intimal injury and the intramural hematoma, formal aortic repair was agreed to be unnecessary at initial presentation in the setting of damage control principles of hemorrhage and intestinal contamination control. Aside from observation that the
Vol. 29, No. 6, August 2015
patient had adequate perfusion to the lower extremities, exploration and the use of intraoperative ultrasound facilitated the decision to pursue conservative management approach with close observation and intervention only if an emergent situation arose. Embarking on a definitive repair at the time of the initial operation, whether aortic or visceral, would have exposed the patient’s arterial repair to a contaminated operative field. Although it has been shown in adults that polytetraflourethylene graft placement in contaminated fields may not result in increased infection rates,17 potential infection risk influences choice of repair toward an autologous conduit in such settings. In addition, the patient’s tenuous hemodynamic status supercedes definitive aortic surgery in terms of repair and potential autograft harvest. Because the patient’s initial operation was in a damage control scenario, the relative hypotension, potential coagulopathy, and hypothermia would place any definitive repair at risk for failure. The patient’s age and size were also in consideration. The patient presented as a 5-ft tall healthy 12-year old weighing 130 lbs. The placement of a graft in a child who will continue to grow has largely unknown long-term consequences. Bardain et al. believe that using synthetic grafts for vascular repair in patients with further growth potential should be avoided because of the fixed size of the aortic repair. Most likely, such patients would require replacement or revision of their graft at a future date. If a vascular graft has to be used in a pediatric patient, it should be larger than necessary to account for future growth.9 Other conduits such as internal iliac artery would have been time consuming and not advisable at the point of initial exploration, and the use of saphenous vein may result in a significant rate of aneurysmal degeneration.15 None of these seemed necessary once the present patient was stabilized. Moreover, in our patient, who is paraplegic, the need for definitive repair is in question secondary to his future limited lower extremity utilization. In conclusion, based on our patient’s condition and the literature review, we believe nonoperative management was the best course of care for our patient. The intraoperative examination with Doppler ultrasound of his aorta, along with his stable and unchanging peripheral pulse examination, allowed us to primarily concern ourselves with the resuscitation and repair of his other injuries rather than having to add an aortic repair to his list of operations. We conclude that, in the setting of hemodynamic instability with intra-
Case reports 1316.e5
abdominal injuries, a patient who has an easily examined, stable, and unchanging pulse examination after blunt injury to the abdominal aorta can undergo nonoperative management of the aortic injury. Prospectively, nonoperative management is further based on the continued monitoring of our patient’s aortic injury for increasing dissection and/or aneurysmal formation. Ultrasonography is appealing because of no exposure to radiation and its ability to demonstrate turbulent flow if present. In addition, the use of the same imaging technique in subsequent examinations will simplify comparison between the studies.18 At present, the patient will be followed with yearly duplex examinations for interval changes and CTA only if additional pathology develops to minimize the effects of ionizing radiation.
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14. Anderson SA, Day M, Chen MK, et al. Traumatic aortic injuries in the pediatric population. J Pediatr Surg 2008;43:1077e81. 15. McCarthy MC, Price SW, Rundell WK, et al. Pediatric blunt abdominal aortic injuries: case report and review of the literature. J Trauma 2007;63:1383e7. 16. Rajagopalan S, Dean SM, Mohler ER, Mukherjee D. Manual of Vascular Diseases. Riverwoods, IL: Wolters Kluwer Health, 2011.
Annals of Vascular Surgery
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