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Computed tomographic angiography in pediatric blunt traumatic vascular injury
Journal of Pediatric Surgery (2008) 43, 549–554
www.elsevier.com/locate/jpedsurg
Computed tomographic angiography in pediatric blunt traumatic vascular injury Edward B. Lineen a , Mariano Faresi a , Michelle Ferrari b , Holly L. Neville a , William R. Thompson a , Juan E. Sola a,⁎ a
Daughtry Family Department of Surgery, University of Miami/Ryder Trauma Center, Jackson Memorial Hospital, Miami, FL 33136, USA b Daughtry Family Department of Radiology, University of Miami/Ryder Trauma Center, Jackson Memorial Hospital, Miami, FL 33136, USA Received 28 September 2007; revised 23 October 2007; accepted 23 October 2007
Key words: Pediatric vascular trauma; Computed tomographic angiography
Abstract Pediatric vascular injuries are rare but can be difficult to diagnose and challenging to manage. We present our experience with computed tomographic angiography in 3 pediatric patients with vascular injuries secondary to blunt trauma. Computed tomographic angiography is noninvasive, fast, rapidly available in most centers, and can evaluate for other injuries. We present a review of the literature and recommend computed tomogra-phic angiography as the diagnostic tool of choice in the evaluation of pediatric blunt vascular trauma. © 2008 Elsevier Inc. All rights reserved.
The management of blunt traumatic vascular injury in the hemodynamically stable patient is challenging and still controversial. Conventional angiography (CA) remains the gold standard diagnostic modality, but it is invasive and associated with significant complications. Over the last several years, multislice helical computed tomographic angiography (CTA) has emerged as an alternative to CA in the evaluation of vascular injuries. Computed tomographic angiography is noninvasive, relatively fast, and reproducible. Other advantages of CTA include the ability to evaluate nearby organs and surrounding tissues, and can provide 3-dimensional images.
Computed tomographic angiography has proven to be sensitive and specific (80% and 100%, respectively) with multiple reports in the literature utilizing this imaging modality in the evaluation of neck [1,2,3] and extremitiy [4,5] injuries. However, CTA in pediatric vascular trauma has been poorly reported. We present our experience with CTA in 3 pediatric patients with blunt limb trauma and potential vascular injuries. We present a review the literature and justify the use of CTA in the evaluation of blunt pediatric vascular trauma.
⁎ Corresponding author. Department of Surgery, Division of Pediatric Surgery, Jackson Memorial Hospital, Holtz Center 3019, Miami, FL 33136. Tel.: +1 305 585 5600; fax: +1 305 326 0224. E-mail addresses: [email protected] (E.B. Lineen), [email protected] (M. Faresi), [email protected] (M. Ferrari), [email protected] (H.L. Neville), [email protected] (W.R. Thompson), [email protected] (J.E. Sola).
1. Case reports
0022-3468/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2007.10.063
1.1. Case 1 An 11-year-old boy was brought to the emergency department after a soccer goal fell on his right leg. The
550
E.B. Lineen et al.
Fig. 1 Four Slice helical CT scans with axial 3.2-mm cuts after administration of IV contrast. A, Hematoma in the posterior compartment of the thigh and leg. Bilateral normal superficial femoral artery above adductor canal. B, Loss of opacification of distal right superficial femoral artery and proximal popliteal artery as passes through adductor canal. C, Reconstituted flow in distal popliteal artery. Note decreased in diameter of vessel. D, Anterior-posterior orientation of 3-dimensional reconstruction showing signal loss in the distal superficial femoral artery and proximal popliteal artery. IV, intravenous.
injured leg was ecchymosed at the level of the right knee but had no deformity. Plain radiography showed no evidence of fracture. Posterior tibialis and dorsalis pedis arterial pulses were not palpable on the right foot, and only a weak Doppler signal could be detected. A CTA of the right lower extremity demonstrated a hematoma in the posterior compartment of the right thigh. In addition, at the level of the adductor canal, there was an injury or possible external compression of the distal superficial femoral artery and proximal popliteal artery with reconstitution of flow in the distal popliteal artery (Fig. 1).
In the operating room, a large hematoma was evacuated, and the injured segment of superficial femoral artery was resected. After proximal and distal thrombectomies, a reversed saphenous vein was used as an interposition graft. Postoperative angiogram showed adequate flow through the anastomosis and 3-vessel runoff.
1.2. Case 2 The patient was an 11-year-old boy transferred from outside hospital after being hit by a car 6 hours earlier. On
CT angiography in pedriatic blunt vascular trauma physical examination, he had a degloving injury with an open knee joint of the right leg. An absent posterior tibialis and a weak dorsalis pedis pulse were noted on the right foot. A CTA of the lower extremity demonstrated an injury to the distal superficial femoral artery in the proximal adductor canal (Fig. 2). The popliteal artery reconstituted 1 cm distal to the injury. In the operating room, a contused short segment of the right superficial femoral artery was found with a surrounding hematoma. The small segment of injured artery was resected, and thrombectomies were performed with return of ante-
551 rograde flow. An end-to-end vascular anastomosis was performed with interrupted 6-0 prolene sutures. Four compartment fasciotomies were performed, the knee joint was irrigated, and the degloving skin loss was debrided to be closed later with a split thickness skin graft.
1.3. Case 3 The patient was a 12-year-old boy who was thrown from an all terrain vehicle after a head on collision with a tree. He presented with stable vital signs. Other than bilateral lower
Fig. 2 Four slice helical CT scan with axial 3.2-mm cuts after administration of IV contrast. A, At the level adductor canal, the distal superficial femoral artery and proximal popliteal artery show a focal filling defect with partial opacification of the vessel. B, Popliteal artery diminished in caliber popliteal 2 cm distal to initial defect. C, Posterior to anterior orientation of 3-dimensional reconstruction showing focal defect in distal superficial femoral artery. There is adequate although diminished signal in reconstituted popliteal and 3-vessel runoff. D, Lateral view of 3-dimensional reconstruction.
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Fig. 3 Four slice helical CT scan with axial 3.2-mm cuts after administration of IV contrast. A, Right femoral artery intact with good signal above the area of injury. Femoral vein without signal (compare to signal from left femoral vein). B, Cuts through level of injury showing good patency of the vein saphenous graft. C, Cuts through level of injury showing thrombosis of the right popliteal vein. D, Cuts below the level of the injury, showing adequate patency of the anterior tibial, posterior tibial, and peroneal vessels.
extremity pain, he had no other complaints. Physical examination was significant for deformities of the right distal femur and left proximal tibia. The left dorsalis pedis and posterior tibialis pulses were not palpable or detectable by Doppler. Neurologic exam showed paralysis of the left foot, along with loss of sensation and proprioception. A limited trauma workup showed a Salter-Harris type II right femur fracture and a grade III proximal left tibial fracture. In the operating room, a large hematoma was found in the left popliteal fossa where a bone fragment had avulsed the popliteal artery from the trifurcation at the level of the division of the anterior tibialis from the tibial-peroneal trunk. The adjacent popliteal vein was also transected. Thrombectomies of the anterior tibialis and peroneal and posterior tibial arteries were performed with good blood return obtained only from the anterior tibial artery. Once external fixation of the left lower extremity was completed, a saphenous vein interposition graft was sewn with interrupted 6-0 prolene sutures to bridge the gap from the popliteal artery to the trifurcation. A postcompletion angiogram showed good outflow only via the anterior tibial artery. A strong
palpable dorsal pedal pulse was present on physical examination. A primary repair on the popliteal vein was performed, and 4 compartment fasciotomies of the left lower extremity were carried out. Open reduction and internal fixation of the right femur fracture was completed, and the patient was taken to the intensive care unit. Approximately 20 hours postoperatively, the patient's left foot became cool and swollen with loss of the palpable pulse. Computed tomographic angiography showed good flow through the anastomosis with 3-vessel runoff (Fig. 3). Computed tomographic angiography also demonstrated a femoral-popliteal deep vein thrombosis, and the patient's symptoms resolved with a heparin drip.
2. Discussion Blunt traumatic vascular injury is rare in the pediatric population. Puapong et al [6] found that, of the 2477 patients younger than 14 years admitted with blunt trauma over a 10-year period, less then 0.7% had a vascular injury.
CT angiography in pedriatic blunt vascular trauma DeVirgilio and Mercado [7], in a 10-year review of pediatric vascular trauma, found only 4 patients with blunt vascular injury. More recently, in a review by Klinkner et al [8] of 7553 pediatric blunt trauma patients, only 0.4% had a vascular injury. Diagnosis of a vascular injury in the pediatric population is difficult. This is compounded by the need to make an accurate and timely diagnosis because missed and delayed injuries have severe consequences. This is most evident with popliteal artery injuries where the diagnosis can be difficult to make and delay leads to higher rates of neuropathy and amputation [9]. Both of these complications can be directly attributable to prolonged ischemia time [10]. The tools at our disposal for making the correct diagnosis are knowledge of the mechanism of injury, physical examination, and diagnostic imaging modalities. The mechanism of injury, such as certain types of fractures, tibial plateau, or supracondylar humerus fractures, is well known to be associated with vascular injuries. Traditionally, all posterior knee dislocations were required to have an angiogram to exclude an associated vascular injury. However, a recent review by Hollis and Daley [11] showed that there is a 100% sensitivity and specificity for physical examination diagnosing surgically significant popliteal trauma associated with posterior knee dislocation. Physical exam is also very reliable when the “hard signs” are present, such that physical examination has 95% sensitivity for therapeutic intervention [12]. When no obvious clinical sign other than proximity of fracture or mechanism of injury is present, Doppler Pressure Indices can give a negative predictive value 94% if greater then 0.9 [13-15] and 99% if greater than 1 [12]. However, when hard signs are not present and clinical suspicion or abnormal Doppler Pressure Indices is present, an imaging study is warranted to evaluate for vascular injury. Because of the rarity of pediatric vascular trauma, no imaging tool other than angiography has been widely studied. The validity of ultrasound in pediatric vascular trauma was examined in a 1999 review of blunt carotid injuries. A review of the National Pediatric Database showed an incidence of 0.035% in 57 659 patients with trauma. However, owing to the small size of the group, no conclusion could be drawn as to the efficacy of ultrasound in the diagnosis in pediatric patients with blunt carotid injuries [16]. Computed tomographic angiography has been studied in the adult trauma patient and is now considered an acceptable alternative to contrast angiography. Because of CTA being less invasive and the ability for 3-dimensional reconstructions, it is now the primary diagnostic tool for extremity [4,5,17], carotid [1-3,18] and thoracoabdominal [19,20] vascular trauma. The 3-year prospective evaluation of Inaba [17] showed CTA diagnostic in 62 of 63 patients. There was only 1 nondiagnostic study secondary to metallic artifact from the projectile, thus this study achieved a sensitivity and specificity of 100%.
553 Multislice helical CTA has been used for vascular diagnosis in pediatric patients outside the realm of trauma. A prospective observational trial in 20 pediatric patients 2 to 10 years of age post liver transplantation showed that CTA had 90% accuracy, 86% sensitivity, 100% specificity, 100% positive predictive value, and 74% negative predictive value in the diagnosis of hepatic artery thrombosis or stenosis and portal vein stenosis or occlusion in patients with a suspicion of biliary or vascular compromise [21]. Recently, the 64-slice computed tomographic (CT) scanner has been shown to be as effective as angiography in evaluating congenital heart disease by demonstrating the major vascular structures and the proximal right and left coronary arteries [22]. Computed tomographic angiography has also been used instead of contrast angiography for surgical planning in repair of pediatric brachial artery pseudoaneurysms after catheterizations [23]. The benefits of CTA are not only that it is widely available and can be rapidly obtained, but most importantly, it is noninvasive, which translates to lower complications compared with CA. The complications for contrast angiography are well studied in pediatric patients because of the large experience with cardiac catheterizations. Although initial prospective studies showed a femoral artery complication rate to be as high as 24% [24], acute femoral artery thrombosis generally varies from 2% to 8.6% [25,26]. Chronic femoral artery occlusion, though not always symptomatic, leads to a high rate of limb length deformity [27]. More recently, Taylor et al [28] studied postcatheterization complications in 58 patients who had procedures under the age of 5 years. The patients were studied 5 to 14 years after their procedure. The rate of femoral artery occlusion was as high as 33%, with average decrease in ankle brachial index (ABI) to 0.79 and an 8% rate of limb growth retardation. However, clinically, only 1 patient had symptoms of ischemia, and only 1 patient had a gait disturbance. Because of the noninvasiveness of CTA, none of these complications are a factor. Radiation exposure and contrast-induced nephropathy are potential risks for either CTA or CA. The ability to control radiation exposure during multislice CTA in pediatric patients is possible by controlling parameters such as scan passes, x-ray tube current, peak voltage, pitch factor, and gantry rotation time, as described by Chan and Rubin [29]. This is important because pediatric patients up to 10 years of age are generally more sensitive to ionizing radiation [30]. Contrast-induced nephropathy is well studied in adults [31,32], although little has been described in children. Both CTA and CA limit the contrast used to the minimal acceptable dose. In conclusion, pediatric vascular injuries are rare and clinically challenging injuries. The diagnosis and treatment must be made quickly but never without proper stabilization of the patient and attention to life threatening conditions. When physical examination shows “hard signs” of a vascular injury, surgical intervention is warranted with no other imaging studies. When “hard signs” of a vascular injury are
554 not present, but there is high suspicion then we propose imaging with CTA as the diagnostic tool of choice. It is noninvasive, highly accurate with a near 100% sensitivity and specificity in the adult population, rapidly available in most centers, and has the ability to simultaneously evaluate the entire body for other injuries. This is well illustrated in our 3 patients but, especially, in the last patient in whom CTA not only saved the patient from an unnecessary invasive procedure such as CA or reexploration but also made the diagnosis of deep venous thrombosis. Although data on pediatric trauma patients evaluated by CTA is extremely limited, its effectiveness can be extrapolated from adult trauma data and its nontraumatic pediatric uses. To more clearly define its usefulness in the pediatric trauma setting, a multicenter prospective trial will most likely be needed.
References [1] Berne JD, Norwood SH, McAuley CE, et al. Helical computed tomographic angiography: an excellent screening test for blunt cerebrovascular injury. J Trauma 2004;57:11-7 [discussion 17-9]. [2] Rogers FB, Baker EF, Osler TM, et al. Computed tomographic angiography as a screening modality for blunt cervical arterial injuries: preliminary results. J Trauma 1999;47:438-9. [3] Biffl WL, Ray CE, Moore EE, et al. Noninvasive diagnosis of blunt cerebrovascular injuries: a preliminary report. J Trauma 2002;53: 850-6. [4] Soto JA, Munera F, Cardoso N, et al. Diagnostic performance of helical CT angiography in trauma to large arteries of the extremities. J Comput Assist Tomogr 1999;23:188-96. [5] Busquets AR, Acosta JA, Colon E, et al. Helical computed tomographic angiography for the diagnosis of traumatic arterial injuries of the extremities. J Trauma 2004;56:625-8. [6] Puapong D, Brown C, Katz M, et al. Angiography and the pediatric trauma patient: a 10 year review. J Ped Surg 2006;41:1859-63. [7] de Virgilio C, Mercado P, Arnell T, et al. Non-iatrogenic pediatric vascular trauma. A ten-year experience at a level one trauma center. Am Surg 1997;63:781-4. [8] Klinker DB, Arca MJ, Lewis BD, et al. Pediatric vascular injuries: patterns of injury, morbidity and mortality. J Ped Surg 2007;42:178-83. [9] Pretre R, Bruchweiler I, Rossier J, et al. Lower limb trauma with injury to the popliteal vessels. J Trauma 1996;40:595-601. [10] Hossny A. Blunt popliteal artery injury with complete lower limb ischemia: is routine use of temporary arterial shunting justified. J Vasc Surg 2004;40:61-6. [11] Hollis JD, Daley BJ. 10 year review of knee dislocations: is arteriography always necessary? J Trauma 2005;59:672-5. [12] Conrad MF, Patton JH, Parikshak M, et al. Evaluation of vascular injury in penetrating extremity trauma: angiographers stay home. Am Surg 2002;68:269-75. [13] Gelberman RH, Menon J, Fronek A. The peripheral pulse following arterial injury. J Trauma 1980;20:948-50.
E.B. Lineen et al. [14] Schwartz MR, Weaver FA, Bauer M. Refining the indications for arteriography in penetrating extremity trauma: a prospective analysis. J Vasc Surg 1993;17:116-24. [15] Nassura ZE, Ivatury RR, Simon RJ. A reassessment of Doppler pressure indices in the detection of arterial lesions in proximity penetrating injuries of extremities: a prospective study. Am J Emerg Med 1996;14:151-6. [16] Lew SM, Frumiento C, Wald SL. Pediatric blunt carotid injury: a review of the national pediatric trauma registry. Pediatr Neurosurg 1999;30:239-44. [17] Inaba K, Potzman J, Munera F, et al. Multi-slice CT angiography for arterial evaluation in the injured lower extremity. J Trauma 2006;60:502-6. [18] Rozycki GS, Tremblay L, Feliciano DV, et al. A prospective study for the detection of vascular injury in adult and pediatric patients with cervicothoracic seat belt signs. J Trauma 2002;52:618-24. [19] Ellis JD, Mayo JR. Computed tomography evaluation of traumatic rupture of the thoracic aorta: an outcome study. Can Assoc Radiol J 2007;58:22-6. [20] Mirvis SE, Shanmuganathan K, Miller BH, et al. Traumatic aortic injury: diagnosis with contrast enhanced thoracic CT—5 year experience at a major trauma center. Radiology 1996;200:413-22. [21] Cheng YF, Chen CL, Huang TL, et al. 3DCT angiography for detection of vascular complications in pediatric liver transplantation. Liver Transpl 2004;10:248-52. [22] Dogan OF, Karcaaltincaba M, Yorgancioglu C, et al. Demonstration of coronary arteries and major cardiac vascular structures in congenital heart disease by cardiac multidetector computed tomography angiography. Heart Surg Forum 2007;10:90-4. [23] Dzepina I, Josip U, Davor M, et al. Pseudoaneurysms of the brachial artery following venipuncture in infants. Pediatric Surg Int 2004;20: 594-7. [24] Flanigan DP, Keifer TJ, Schuler JJ, et al. Experience with iatrogenic pediatric vascular injuries. Ann Surg 1983;198:430-42. [25] Lin PH, Dodson TF, Bush RL, et al. Surgical intervention for complications caused by femoral artery catheterization in pediatric patients. J Vasc Surg 2001;33:1071-8. [26] Ino T, Benson LN, Freddom RM, et al. Thrombolytic therapy for femoral artery thrombosis after pediatric cardiac catheterization. Am Heart J 1988;115:633-9. [27] Smith C, Green RM. Pediatric vascular injuries. Surgery 1981;90: 20-31. [28] Taylor LM, Troutman R, Feliciano P, et al. Late complications after femoral artery catheterization in children less then 5 years of age. J Vasc Surg 1990;11:297-304. [29] Chan FP, Rubin GD. MDCT angiography of pediatric vascular diseases of the abdomen, pelvis and extremities. Pediatr Radiol 2005;35:40-53. [30] 1990 Recommendation of the International Commission of Radiologic Protection (1990) ICRP Publication 60. Ann, ICRP21. No 1-3. The International Commission on Radiologic Protection. [31] Tumlin J, Stacul F, Adam A, et al. CIN consensus working panel pathophysiology of contrast induced nephropathy. Am J Cardiol 2006;98:14-20. [32] Tumlin J, Stacul F, Adam A, et al. CIN consensus working panel strategies to reduce the risk of contrast induced nephropathy. Am J Cardiol 2006;98:59-77.
www.elsevier.com/locate/jpedsurg
Computed tomographic angiography in pediatric blunt traumatic vascular injury Edward B. Lineen a , Mariano Faresi a , Michelle Ferrari b , Holly L. Neville a , William R. Thompson a , Juan E. Sola a,⁎ a
Daughtry Family Department of Surgery, University of Miami/Ryder Trauma Center, Jackson Memorial Hospital, Miami, FL 33136, USA b Daughtry Family Department of Radiology, University of Miami/Ryder Trauma Center, Jackson Memorial Hospital, Miami, FL 33136, USA Received 28 September 2007; revised 23 October 2007; accepted 23 October 2007
Key words: Pediatric vascular trauma; Computed tomographic angiography
Abstract Pediatric vascular injuries are rare but can be difficult to diagnose and challenging to manage. We present our experience with computed tomographic angiography in 3 pediatric patients with vascular injuries secondary to blunt trauma. Computed tomographic angiography is noninvasive, fast, rapidly available in most centers, and can evaluate for other injuries. We present a review of the literature and recommend computed tomogra-phic angiography as the diagnostic tool of choice in the evaluation of pediatric blunt vascular trauma. © 2008 Elsevier Inc. All rights reserved.
The management of blunt traumatic vascular injury in the hemodynamically stable patient is challenging and still controversial. Conventional angiography (CA) remains the gold standard diagnostic modality, but it is invasive and associated with significant complications. Over the last several years, multislice helical computed tomographic angiography (CTA) has emerged as an alternative to CA in the evaluation of vascular injuries. Computed tomographic angiography is noninvasive, relatively fast, and reproducible. Other advantages of CTA include the ability to evaluate nearby organs and surrounding tissues, and can provide 3-dimensional images.
Computed tomographic angiography has proven to be sensitive and specific (80% and 100%, respectively) with multiple reports in the literature utilizing this imaging modality in the evaluation of neck [1,2,3] and extremitiy [4,5] injuries. However, CTA in pediatric vascular trauma has been poorly reported. We present our experience with CTA in 3 pediatric patients with blunt limb trauma and potential vascular injuries. We present a review the literature and justify the use of CTA in the evaluation of blunt pediatric vascular trauma.
⁎ Corresponding author. Department of Surgery, Division of Pediatric Surgery, Jackson Memorial Hospital, Holtz Center 3019, Miami, FL 33136. Tel.: +1 305 585 5600; fax: +1 305 326 0224. E-mail addresses: [email protected] (E.B. Lineen), [email protected] (M. Faresi), [email protected] (M. Ferrari), [email protected] (H.L. Neville), [email protected] (W.R. Thompson), [email protected] (J.E. Sola).
1. Case reports
0022-3468/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2007.10.063
1.1. Case 1 An 11-year-old boy was brought to the emergency department after a soccer goal fell on his right leg. The
550
E.B. Lineen et al.
Fig. 1 Four Slice helical CT scans with axial 3.2-mm cuts after administration of IV contrast. A, Hematoma in the posterior compartment of the thigh and leg. Bilateral normal superficial femoral artery above adductor canal. B, Loss of opacification of distal right superficial femoral artery and proximal popliteal artery as passes through adductor canal. C, Reconstituted flow in distal popliteal artery. Note decreased in diameter of vessel. D, Anterior-posterior orientation of 3-dimensional reconstruction showing signal loss in the distal superficial femoral artery and proximal popliteal artery. IV, intravenous.
injured leg was ecchymosed at the level of the right knee but had no deformity. Plain radiography showed no evidence of fracture. Posterior tibialis and dorsalis pedis arterial pulses were not palpable on the right foot, and only a weak Doppler signal could be detected. A CTA of the right lower extremity demonstrated a hematoma in the posterior compartment of the right thigh. In addition, at the level of the adductor canal, there was an injury or possible external compression of the distal superficial femoral artery and proximal popliteal artery with reconstitution of flow in the distal popliteal artery (Fig. 1).
In the operating room, a large hematoma was evacuated, and the injured segment of superficial femoral artery was resected. After proximal and distal thrombectomies, a reversed saphenous vein was used as an interposition graft. Postoperative angiogram showed adequate flow through the anastomosis and 3-vessel runoff.
1.2. Case 2 The patient was an 11-year-old boy transferred from outside hospital after being hit by a car 6 hours earlier. On
CT angiography in pedriatic blunt vascular trauma physical examination, he had a degloving injury with an open knee joint of the right leg. An absent posterior tibialis and a weak dorsalis pedis pulse were noted on the right foot. A CTA of the lower extremity demonstrated an injury to the distal superficial femoral artery in the proximal adductor canal (Fig. 2). The popliteal artery reconstituted 1 cm distal to the injury. In the operating room, a contused short segment of the right superficial femoral artery was found with a surrounding hematoma. The small segment of injured artery was resected, and thrombectomies were performed with return of ante-
551 rograde flow. An end-to-end vascular anastomosis was performed with interrupted 6-0 prolene sutures. Four compartment fasciotomies were performed, the knee joint was irrigated, and the degloving skin loss was debrided to be closed later with a split thickness skin graft.
1.3. Case 3 The patient was a 12-year-old boy who was thrown from an all terrain vehicle after a head on collision with a tree. He presented with stable vital signs. Other than bilateral lower
Fig. 2 Four slice helical CT scan with axial 3.2-mm cuts after administration of IV contrast. A, At the level adductor canal, the distal superficial femoral artery and proximal popliteal artery show a focal filling defect with partial opacification of the vessel. B, Popliteal artery diminished in caliber popliteal 2 cm distal to initial defect. C, Posterior to anterior orientation of 3-dimensional reconstruction showing focal defect in distal superficial femoral artery. There is adequate although diminished signal in reconstituted popliteal and 3-vessel runoff. D, Lateral view of 3-dimensional reconstruction.
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Fig. 3 Four slice helical CT scan with axial 3.2-mm cuts after administration of IV contrast. A, Right femoral artery intact with good signal above the area of injury. Femoral vein without signal (compare to signal from left femoral vein). B, Cuts through level of injury showing good patency of the vein saphenous graft. C, Cuts through level of injury showing thrombosis of the right popliteal vein. D, Cuts below the level of the injury, showing adequate patency of the anterior tibial, posterior tibial, and peroneal vessels.
extremity pain, he had no other complaints. Physical examination was significant for deformities of the right distal femur and left proximal tibia. The left dorsalis pedis and posterior tibialis pulses were not palpable or detectable by Doppler. Neurologic exam showed paralysis of the left foot, along with loss of sensation and proprioception. A limited trauma workup showed a Salter-Harris type II right femur fracture and a grade III proximal left tibial fracture. In the operating room, a large hematoma was found in the left popliteal fossa where a bone fragment had avulsed the popliteal artery from the trifurcation at the level of the division of the anterior tibialis from the tibial-peroneal trunk. The adjacent popliteal vein was also transected. Thrombectomies of the anterior tibialis and peroneal and posterior tibial arteries were performed with good blood return obtained only from the anterior tibial artery. Once external fixation of the left lower extremity was completed, a saphenous vein interposition graft was sewn with interrupted 6-0 prolene sutures to bridge the gap from the popliteal artery to the trifurcation. A postcompletion angiogram showed good outflow only via the anterior tibial artery. A strong
palpable dorsal pedal pulse was present on physical examination. A primary repair on the popliteal vein was performed, and 4 compartment fasciotomies of the left lower extremity were carried out. Open reduction and internal fixation of the right femur fracture was completed, and the patient was taken to the intensive care unit. Approximately 20 hours postoperatively, the patient's left foot became cool and swollen with loss of the palpable pulse. Computed tomographic angiography showed good flow through the anastomosis with 3-vessel runoff (Fig. 3). Computed tomographic angiography also demonstrated a femoral-popliteal deep vein thrombosis, and the patient's symptoms resolved with a heparin drip.
2. Discussion Blunt traumatic vascular injury is rare in the pediatric population. Puapong et al [6] found that, of the 2477 patients younger than 14 years admitted with blunt trauma over a 10-year period, less then 0.7% had a vascular injury.
CT angiography in pedriatic blunt vascular trauma DeVirgilio and Mercado [7], in a 10-year review of pediatric vascular trauma, found only 4 patients with blunt vascular injury. More recently, in a review by Klinkner et al [8] of 7553 pediatric blunt trauma patients, only 0.4% had a vascular injury. Diagnosis of a vascular injury in the pediatric population is difficult. This is compounded by the need to make an accurate and timely diagnosis because missed and delayed injuries have severe consequences. This is most evident with popliteal artery injuries where the diagnosis can be difficult to make and delay leads to higher rates of neuropathy and amputation [9]. Both of these complications can be directly attributable to prolonged ischemia time [10]. The tools at our disposal for making the correct diagnosis are knowledge of the mechanism of injury, physical examination, and diagnostic imaging modalities. The mechanism of injury, such as certain types of fractures, tibial plateau, or supracondylar humerus fractures, is well known to be associated with vascular injuries. Traditionally, all posterior knee dislocations were required to have an angiogram to exclude an associated vascular injury. However, a recent review by Hollis and Daley [11] showed that there is a 100% sensitivity and specificity for physical examination diagnosing surgically significant popliteal trauma associated with posterior knee dislocation. Physical exam is also very reliable when the “hard signs” are present, such that physical examination has 95% sensitivity for therapeutic intervention [12]. When no obvious clinical sign other than proximity of fracture or mechanism of injury is present, Doppler Pressure Indices can give a negative predictive value 94% if greater then 0.9 [13-15] and 99% if greater than 1 [12]. However, when hard signs are not present and clinical suspicion or abnormal Doppler Pressure Indices is present, an imaging study is warranted to evaluate for vascular injury. Because of the rarity of pediatric vascular trauma, no imaging tool other than angiography has been widely studied. The validity of ultrasound in pediatric vascular trauma was examined in a 1999 review of blunt carotid injuries. A review of the National Pediatric Database showed an incidence of 0.035% in 57 659 patients with trauma. However, owing to the small size of the group, no conclusion could be drawn as to the efficacy of ultrasound in the diagnosis in pediatric patients with blunt carotid injuries [16]. Computed tomographic angiography has been studied in the adult trauma patient and is now considered an acceptable alternative to contrast angiography. Because of CTA being less invasive and the ability for 3-dimensional reconstructions, it is now the primary diagnostic tool for extremity [4,5,17], carotid [1-3,18] and thoracoabdominal [19,20] vascular trauma. The 3-year prospective evaluation of Inaba [17] showed CTA diagnostic in 62 of 63 patients. There was only 1 nondiagnostic study secondary to metallic artifact from the projectile, thus this study achieved a sensitivity and specificity of 100%.
553 Multislice helical CTA has been used for vascular diagnosis in pediatric patients outside the realm of trauma. A prospective observational trial in 20 pediatric patients 2 to 10 years of age post liver transplantation showed that CTA had 90% accuracy, 86% sensitivity, 100% specificity, 100% positive predictive value, and 74% negative predictive value in the diagnosis of hepatic artery thrombosis or stenosis and portal vein stenosis or occlusion in patients with a suspicion of biliary or vascular compromise [21]. Recently, the 64-slice computed tomographic (CT) scanner has been shown to be as effective as angiography in evaluating congenital heart disease by demonstrating the major vascular structures and the proximal right and left coronary arteries [22]. Computed tomographic angiography has also been used instead of contrast angiography for surgical planning in repair of pediatric brachial artery pseudoaneurysms after catheterizations [23]. The benefits of CTA are not only that it is widely available and can be rapidly obtained, but most importantly, it is noninvasive, which translates to lower complications compared with CA. The complications for contrast angiography are well studied in pediatric patients because of the large experience with cardiac catheterizations. Although initial prospective studies showed a femoral artery complication rate to be as high as 24% [24], acute femoral artery thrombosis generally varies from 2% to 8.6% [25,26]. Chronic femoral artery occlusion, though not always symptomatic, leads to a high rate of limb length deformity [27]. More recently, Taylor et al [28] studied postcatheterization complications in 58 patients who had procedures under the age of 5 years. The patients were studied 5 to 14 years after their procedure. The rate of femoral artery occlusion was as high as 33%, with average decrease in ankle brachial index (ABI) to 0.79 and an 8% rate of limb growth retardation. However, clinically, only 1 patient had symptoms of ischemia, and only 1 patient had a gait disturbance. Because of the noninvasiveness of CTA, none of these complications are a factor. Radiation exposure and contrast-induced nephropathy are potential risks for either CTA or CA. The ability to control radiation exposure during multislice CTA in pediatric patients is possible by controlling parameters such as scan passes, x-ray tube current, peak voltage, pitch factor, and gantry rotation time, as described by Chan and Rubin [29]. This is important because pediatric patients up to 10 years of age are generally more sensitive to ionizing radiation [30]. Contrast-induced nephropathy is well studied in adults [31,32], although little has been described in children. Both CTA and CA limit the contrast used to the minimal acceptable dose. In conclusion, pediatric vascular injuries are rare and clinically challenging injuries. The diagnosis and treatment must be made quickly but never without proper stabilization of the patient and attention to life threatening conditions. When physical examination shows “hard signs” of a vascular injury, surgical intervention is warranted with no other imaging studies. When “hard signs” of a vascular injury are
554 not present, but there is high suspicion then we propose imaging with CTA as the diagnostic tool of choice. It is noninvasive, highly accurate with a near 100% sensitivity and specificity in the adult population, rapidly available in most centers, and has the ability to simultaneously evaluate the entire body for other injuries. This is well illustrated in our 3 patients but, especially, in the last patient in whom CTA not only saved the patient from an unnecessary invasive procedure such as CA or reexploration but also made the diagnosis of deep venous thrombosis. Although data on pediatric trauma patients evaluated by CTA is extremely limited, its effectiveness can be extrapolated from adult trauma data and its nontraumatic pediatric uses. To more clearly define its usefulness in the pediatric trauma setting, a multicenter prospective trial will most likely be needed.
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