Traumatic Transection of the Aorta and Thoracic Spinal Cord Injury Without Radiographic Abnormality in an Adult Patient

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1 J ENDOVASC THER 131 CASE REPORT Traumatic Transection of the Aorta and Thoracic Spinal Cord Injury Without Radiographic Abnormality in an Adult Patient Burkhart Zipfel, MD 1 ; Semih Buz, MD 1 ; Dietrich Hullmeine, MD 2 ; Rainer Röttgen, MD 3 ; and Roland Hetzer, MD, PhD 1 1 Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany. 2 Department of Neurology, DRK-Kliniken Köpenick, Berlin, Germany. 3 Department of Radiology, Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany. Purpose: To describe a rare case of spinal cord injury without radiographic abnormalities (SCIWORA) associated with a traumatic aortic transection. Case Report: A 48-year-old man was transferred for endovascular treatment of a traumatic aortic transection. Primary traumatic paraplegia had been documented at the scene of the accident. No osseous or ligamentous injuries were found in the conventional radiographic images. The transection was treated successfully with an endovascular stent-graft, but the patient remained paraplegic. On the magnetic resonance images 8 days later, discrete trauma of the intraspinal ligament at T1/T2 was seen, without signs of injury to the myelum. The patient made a slow but incomplete recovery after that. Conclusion: SCIWORA very rarely affects the thoracic spinal cord in adults; therefore, a vascular injury in relation to the trauma of the aorta is assumed. When spinal cord damage is noted after stent-grafting or open aortic surgery for traumatic transection, SCIWORA should be ruled out by history and neurological examination. J Endovasc Ther. Key words: thoracic aorta, traumatic aortic transection, spinal cord injury without radiographic abnormalities (SCIWORA), paraplegia, stent-graft Endovascular stent-grafting has evolved into a valuable alternative to conventional open surgery to repair traumatic aortic transection with minimal additional trauma, even in acutely injured patients. 1 The low risk of paraplegia is deemed an advantage of the procedure, but the influence of trauma on this complication remains unclear. We encountered a patient whose condition raised new questions about the mechanism of paraplegia. CASE REPORT A 48-year-old man suffered a head-on traffic accident in which the safety harness and airbag worked properly, but he was trapped in the car for about an hour. Paraplegia was documented at the scene by the emergency physician; the patient was intubated as a rescue maneuver and bilateral chest tubes were inserted. Emergent whole body computed tomography (CT) was performed on Burkhart Zipfel discloses a financial relationship with Nicolai GmbH, Langenhagen, Germany, as proctor for thoracic endografting with the Relay device. The other authors have no commercial, proprietary, or financial interest in any products or companies described in this article. Address for correspondence and reprints: Burkhart Zipfel, MD, Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, Berlin, Germany. zipfel@dhzb.de ß 2010 by the INTERNATIONAL SOCIETY OF ENDOVASCULAR SPECIALISTS Available at

2 132 TRAUMATIC TRANSECTION AND SCIWORA J ENDOVASC THER Figure 1 Sagittal CT reconstruction 1.5 hours after the trauma shows traumatic transection well behind the left subclavian artery accompanied by mediastinal and periaortic hematoma. admission to another hospital 1.5 hours after the trauma. Aortic transection with a false aneurysm was situated in the proximal descending thoracic aorta beginning 15 mm distal of the left subclavian artery (LSA). A periaortic hematoma extended up to the aortic arch (Fig. 1). Further injuries were noted, including blunt thoracic trauma with bilateral hemothorax, brain injury with minor subdural and subarachnoidal hematoma not requiring neurosurgical intervention, and contusion of the right kidney but no fractures of the extremities. The plain radiographs and vertebral CT scans showed no fractures or dislocation of the spine. The injury severity score (ISS) was calculated as 36. Clinical neurological examination when the sedation was interrupted using non-verbal communication with the patient still intubated confirmed trauma-induced paraplegia; anterior spinal cord syndrome was suspected because of dissociated sensory loss (selective loss of pain and temperature sensitivity with preservation of fine touch and proprioception). The patient was transferred to our institution 4 days after the trauma, still intubated and hemodynamically stable. Endovascular repair of the aortic injury was performed the next morning in a hybrid operating room equipped with a fixed angiography unit and integrated angiography table (Artis; Siemens, Erlangen, Germany). Using a technique described previously, 2 a 90-mm-long, 22-mmdiameter thoracic stent-graft loaded in a 22-F delivery catheter (Relay; Bolton Medical, Sunrise, FL, USA) was implanted from the retrograde direction through a percutaneous approach to the right common femoral artery using a 10-F percutaneous suture device (Prostar XL; Abbott Vascular Devices, Redwood City, CA, USA) and an extra-stiff guidewire (E-wire; Jotec, Hechingen, Germany). The outer sheath of the Relay delivery system was placed at the diaphragm, and the inner sheath was advanced into the aortic arch for deployment of the stent-graft, with the beginning of the polyester fabric placed exactly behind the LSA (Fig. 2). Procedure time was 35 minutes; 40 ml of non-ionic contrast medium (Ultravist 370; Bayer Schering, Berlin, Germany) were used during the 4 minutes of fluoroscopy. No heparin was administered during the procedure as heparin-induced thrombocytopenia (HIT) was suspected on the basis of the preliminary test result performed before referral. The platelet count on admission was 33,000 and recovered to normal (440,000) within 4 days, ruling out HIT. A follow-up CT scan showed perfect results of stent-grafting with complete thrombosis of the false aneurysm; the remaining aneurysm was visible only as a thickening of the aortic wall around the stent-graft (Fig. 3). The patient was extubated 2 days after the procedure and was completely paraplegic. The clinical neurological examination confirmed anterior spinal cord syndrome at the T6 level. Spinal magnetic resonance imaging (MRI) performed on the third day, 8 days after the trauma, showed no contusion or other traumatic damage nor ischemic defect of the spinal cord itself (Fig. 4A C). Using T2 inversion-recovery weighted imaging, which discriminates fat from trauma and edema, a collection of fluid could be seen between the spinal processes of T1 and T2 as evidence of soft tissue trauma of the posterior elements in the cervicothoracic junction (Fig. 4D).

3 J ENDOVASC THER TRAUMATIC TRANSECTION AND SCIWORA 133 Figure 2 (A) Intraoperative target angiography before stent-graft implantation shows contained rupture and false aneurysm 15 mm distal to the LSA. (B) Intraoperative completion angiography demonstrates the rupture and false aneurysm occluded by the stent-graft placed exactly distal to the LSA, which remains patent. The proximal bare springs cross the LSA. On the 4 th day after the procedure, the 9 th day after the accident, the patient started to move his toes again. The patient was transferred to a rehabilitation unit. Four months after the trauma, a CT scan showed correct position of the endograft and complete Figure 3 Sagittal CT reconstruction 6 days after stent-graft implantation shows the false aneurysm to be completely excluded. shrinkage of the false aneurysm. The level of the motor dysfunction had migrated downward to T12. Sensory and motor evoked potentials showed impairment but no interruption of the neurons (reduced amplitude; delayed reaction). No follow-up MRI of the spine was performed due to lack of therapeutic consequences. The patient was discharged home 5 months after the trauma. At 8 months, the motor function had continuously improved to allow weak spontaneous movements of the legs. The patient is using a wheelchair, but he is able to walk at home with bilateral orthoses. He reports ongoing improvement in small steps. DISCUSSION Endovascular repair of blunt thoracic aortic injury has evolved as a routine procedure in the early post-traumatic phase. 1 Because the procedure is so quick and straightforward, we usually perform it without heparin in multiple injury patients if impaired coagulation is suspected or, as in this case, where HIT is suspected initially. We did not experience any embolic complications as a result of this practice.

4 134 TRAUMATIC TRANSECTION AND SCIWORA J ENDOVASC THER Figure 4 Sagittal magnetic resonance imaging 8 days after the trauma revealed minor ligamentous injury between the spinal processes of T1 and T2 but no myelum damage. (A) T1- weighted sagittal image, (B) T2-weighted sagittal image, and (C) T2-weighted axial image at T9. There is a suspicion of epidural hematoma, extending upwards, in the lower thoracic spine in the T2-weighted sagittal image, which is revealed as flow-induced artifacts when compared to the T1-weighted image. (D) T2 inversion-recovery weighted sagittal image, which discriminates fat from trauma and edema (white signal). Here it detects fluid collection between the spinal processes of T1 and T2 (arrow) as evidence of soft tissue trauma of the posterior elements in the cervicothoracic junction. Aortic transection associated with spinal cord injury without radiographic abnormality (SCIWORA) has been described primarily in children 3 and explained by the flexibility of the immature spine. In adults, it has nearly always been seen in the cervical cord, 4,5 where the spine is flexible and does not protect the cord as much as in the adult

5 J ENDOVASC THER TRAUMATIC TRANSECTION AND SCIWORA 135 thoracic spine. Only a few adult cases of SCIWORA affecting the thoracic spine have been reported. 6,7 The condition is defined as spinal cord injury proven either by clinical neurological examination 4 or by evidence of myelum trauma on MRI 5 without evidence of bony or ligamentous injury (dislocation) in conventional radiographic images. Evidence of direct or indirect spinal cord injury as edema or disc herniation had been detected later in special spinal MRIs in nearly all cases of SCIWORA. 4 7 In our patient, no signs of injury to the myelum were found in MRI after 8 days. Only a discrete soft tissue trauma of the intraspinal ligament was seen in the cervicothoracic junction, which was likely the point of maximum traumatic impact to the spine. Clinical neurological examination revealed a pattern of anterior spinal artery syndrome at T6, which is highly specific for ischemic lesion in the territory of this artery. The lesion may be small enough to be invisible on spinal MRI. Therefore, we suspect that this spinal cord injury was related to segmental vascular injury in relation to the aortic trauma. No injury to the major arteries contributing to collateral perfusion of the upper spinal cord was noted; the left subclavian artery (LSA) 8 remained unimpaired by the trauma and the endovascular procedure, and vertebral artery thrombosis 9 was ruled out in the CT scans. Originating in the thoracoabdominal segment, the artery of Adamkiewicz was too far away to play a role in this aortic trauma, which typically affects the isthmus, or to be impaired by the short proximal stent-grafts that are usually implanted for traumatic lesions, with a nearly zero incidence of procedure-related spinal cord ischemia. 1,10 We assume that the shearing forces that where responsible for the blunt aortic injury may have affected one or more segmental arteries leading to localized dissection or thrombosis, which caused localized spinal cord ischemia invisible on MRI. This scenario may be another possible mechanism of adult thoracic SCIWORA, which has not hitherto been described in combination with blunt thoracic aortic injury. Conclusion When spinal cord damage is noted after stent-grafting or open aortic surgery for traumatic transection, traumatic spinal cord injury without radiographic abnormalities should be taken into account. Meticulous neurological examination in trauma patients before aortic procedures is mandatory. In this case, the patient s recovery from the traumainduced paraplegia was apparently not impaired by the aortic procedure, perhaps owing to short coverage of the proximal aorta and maintained LSA flow. Acknowledgment: We thank Anne Gale, ELS, for editorial assistance. REFERENCES 1. Buz S, Zipfel B, Mulahasanovic S, et al. Conventional surgical repair and endovascular treatment of acute traumatic aortic rupture. Eur J Cardiothorac Surg. 2008;33: Zipfel B, Buz S, Hammerschmidt R, et al. Early clinical experience with the E-vita thoracic stent-graft system: a single center study. J Cardiovasc Surg (Torino). 2008;49: Pang D, Wilberger J. Spinal cord injury without radiographic abnormalities in children. J Neurosurg. 1982;57: Kato H, Kimura A, Sasaki R, et al. Cervical spinal cord injury without bony injury: a multicenter retrospective study of emergency and critical care centers in Japan. J Trauma. 2008;65: Hendey GW, Wolfson AB, Mower WR, et al. Spinal cord injury without radiographic abnormality: results of the National Emergency X- Radiograph Utilization Study in blunt cervical trauma. J Trauma. 2002;53: Samsani SR, Calthorpe D, Geutjens G. Thoracic spinal cord injury without radiographic abnormality in a skeletally mature patient: a case report. Spine. 2003;28:E Van Buul G, Oner FC. Thoracic spinal cord injury without radiographic abnormality in an adult patient. Spine J. 2009;9:e Zipfel B, Buz S, Hammerschmidt R, et al. Occlusion of the left subclavian artery in endovascular stent-grafting is safer with protective surgical reconstruction of the artery. Ann Thorac Surg. 2009;88:

6 136 TRAUMATIC TRANSECTION AND SCIWORA J ENDOVASC THER 9. Torina PJ, Flanders AE, Carrino JA, et al. Incidence of vertebral artery thrombosis in cervical spine trauma: correlation with severity of spinal cord injury. Am J Neuroradiol. 2005;26: Xenos ES, Minion DJ, Davenport DL, et al. Endovascular versus open repair for descending thoracic aortic rupture: institutional experience and meta-analysis. Eur J Cardiothorac Surg. 2009;35: