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Congenital Single, Pelvic Iliac Artery: A Case Report
Brief Reports
Congenital Single, Pelvic Iliac Artery: A Case Report Daniel P. Link, MD, Armando S. Garza, BS, and Wayne L. Monsky, MD, PhD
Congenital vascular anomalies of pelvis and lower limb arteries are rare. During embryologic development, the sciatic artery represents the dominant supplier of blood to the lower limb. The external iliac and femoral arteries appear later in the process and take over as the sciatic artery regresses. Failure of the sciatic artery to regress creates a persistent sciatic artery malformation. Failure of the external iliac artery to properly bud may lead to similar vascular malformations. The authors present a patient with atresia of the left external iliac artery with an associated atresia of the left common iliac vein, duplication of the infrarenal inferior vena cava, and absence of the left S1 bony arch. The left-sided single iliac artery supplies both pelvic structures and the lower limb. The “pelvic” external iliac artery may result from embryologic budding at a lower segmental level than the usual fifth lumbar segmental artery. This combination of anomalies suggests an abnormality of segmentation on left at the first sacral level. J Vasc Interv Radiol 2009; 20:1231–1234 Abbreviation:
PSA ⫽ persistent sciatic artery
SIMILAR to cases of persistent sciatic artery (PSA) (1,2), congenital vascular anomalies of the pelvis and lower limb arteries are rare. Greeb (3) described only six iliofemoral anomalies in a series of 8,000 patients who underwent angiography. Atresia of the external iliac artery is considered to be extremely rare (4), with only a few cases reported in the literature (5–7). Congenital vascular anomalies of the pelvis and lower limb arteries may be symptomatic, causing symptoms of claudication or thrombosis (4); however, there are cases of asymptomatic anomalies that only become apparent at autopsy or imaging. Herein, we report a case of a single, left-sided iliac artery that follows a pelvic course and continues as a normal
From the Department of Radiology, Division of Vascular and Interventional Radiology, University of California, Davis, Medical Center, 4860 Y St, Ste 3400, Sacramento, CA 95817. Received August 27, 2008; final revision received May 23, 2009; accepted May 27, 2009. Address correspondence to D.P.L.; E-mail: [email protected] None of the authors have identified a conflict of interest. © SIR, 2009 DOI: 10.1016/j.jvir.2009.05.042
common femoral artery with subsequent normal branching.
CASE REPORT The patient, a 28-year-old man, was a passenger in a motor vehicle collision who was brought into our medical center emergently because of hypotension. He was successfully resuscitated with crystalloid boluses and 3 units of packed red blood cells. The pulse examination was normal. Computed tomography (CT) of the abdomen showed a small liver laceration and contrast medium extravasation thought to be secondary to mesenteric artery injury. Incidental notes were made regarding an absent leftsided sacral arch at S1 and the iliac artery anomaly. Subsequently, the patient underwent laparotomy and achieved hemostasis. The patient had bilateral nondisplaced pubic rami fractures without pelvic hematoma, a right displaced femoral fracture, and left forefoot injury. Arteriography of the left lower extremity was performed for the evaluation of his pelvic and lower extremity circulation before right femur fixation and forefoot repair. Arteriography revealed a normal abdominal aorta and no ab-
dominal or pelvic bleed. However, a single left iliac artery was noted having internal iliac artery branches including the anterior and posterior divisions (Figs 1, 2). This single left iliac artery descended into the pelvis and then coursed laterally and anteriorly, immediately proximal to the superior and inferior gluteal artery origins. This artery was continuous with the left common femoral artery, which branched to a normal deep and superficial artery that gave rise to a normal popliteal artery. The right iliac arteries and runoff were normal. There was normal three-vessel runoff to both feet. Review of the contrast-enhanced CT scan revealed the course of the left iliac artery and associated anomalies (Fig 3). In this patient, the right common iliac bifurcates at 6cm distal to the aortic bifurcation; however, the left common iliac artery persists as a single artery (Fig 3b). This single artery descends into the pelvis medial to the psoas muscle. This artery continues medially with the internal iliac vein, becoming the posterior division artery. Immediately before the superior and inferior gluteal artery takeoff, this large artery courses anteriolaterally
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Figure 1.
Congenital Single, Pelvic Iliac Artery
Arteriogram shows a single left iliac artery that takes an anomalous course.
from the obterator internus muscle and medial to the iliacus muscle, traveling lateral to a companion vein (Fig 3d, 3e). This artery enters the inguinal canal, forming a femoral artery at the level of the inferior epigastric and deep circumflex iliac arteries (Fig 3f). The common iliac vein is marked distally by an intravenous catheter. The vein follows the course of the artery and drains into a left-sided inferior vena cava and the left renal vein. No left common iliac vein is seen on the CT scan.
DISCUSSION The development of lower limb arteries begins as an extension of the paired dorsal aorta and intersegmental arteries during the 3rd week of gestation (8). These paired vessels have dorsal portions that supply the developing neural tube and ventral portions that supply muscle and skin; the ventral portions later develop into intercostal arteries in the thoracic region. In the lumbar area, the fifth pair of intersegmental arteries develops a distal bud. From this bud, the sacral segmental arteries develop along the axial (sciatic) artery of the lower limb. The first portion of this segmental artery develops as the internal iliac artery.
This axial artery is usually temporary, as the later-appearing external iliac artery is destined to take over the arterial supply to the leg by day 60 (8). The external artery bud usually arises from this 5th lumbar intersegmental branch (the umbilical artery) proximal to the axial artery origin (3). The sciatic artery begins to degenerate as the external iliac and femoral artery demand more flow as they supply the “rete femoralis,” a capillary network in the developing muscle mass of the thigh. With less flow, the embryonic axial artery (sciatic artery) fragments and persists as the popliteal, peroneal (fibular), and sciatic nerve arteries. The normal external iliac artery then gives rise to the common femoral artery and its bifurcation. The development of the venous system of the lower extremity is not well documented and is generally believed and assumed to be concurrent with arterial developmental anatomy. Veins and arteries develop as vascular pairs from capillary networks of the developing limb. Other reports of aberrant iliac artery anatomy did not comment on the venous structures. We believe our case is the first to describe such an association. The infrarenal inferior vena cava and left com-
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mon iliac vein are most commonly derived from the sacrocardinal vein and interpostcardinal anasomosis, respectively (9). Persistent left infrarenal vena cava occurs when the interpostcardinal anastomosis fails. In these cases, the left limb drainage is through the postcardinal vein to the left renal vein. The absence of the left sacral arch in addition to the venous anomalies suggests that the arterial anomalies are congenital and not acquired through injury of the vessel. In addition, given the type of tissues involved, the anomaly is likely due to aberrancy in mesodermal development. Other reports did not comment on the bony structures. Tamisier et al (5) classified congenital malformations of the external iliac artery into three groups. Group 1 anomalies are represented by variance in origin or course of the artery. Group 2 anomalies are composed of hypolastic or atretic arteries that are compensated by a PSA. Group 3 arteries are similarly hypolastic; however, they are not compensated by a PSA. In the review by Tamisier et al (5), a case similar to the present case was classified in the group as anomaly of origin and course. This group of patients had normal femoral arteries. It is their origin and course that are abnormal. In the cases of external iliac arteries running a pelvic course (including this report), there is a constant relationship with the inferior and superior gluteal artery origins. The superior gluteal artery level seems to be the most caudal segmental (L5-S1). A normal femoral artery can only be formed from a bud arising cranial to this segment. In cases of PSA, the bud arises in the normal position but the axial artery persists because of flow demand. A high origin of the bud may yield an external iliac artery arising directly from the abdominal aorta (also classified as Tamisier group 1) (5). This present case resembles very closely the anatomy described by Okamoto et al (10) and Testut (11). Okamoto et al (10) believe that the anomalous external iliac bud in their case and similar cases probably occur when the internal iliac artery arises from a more distal segmental artery, derived from the median sacral artery. This
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Figure 2. Selective left common iliac artery digital arteriogram. (a) Right anterior oblique view of the anomalous vessel. (b) Left anterior oblique view of the anomalous vessel.
segment would be L5 or S1, explaining the position of the pelvic external iliac artery and sacral nerve. The anomalies in this case are interesting because, although rare, imaging in the medical population is finding anomalies at an increasing rate. Knowing about anomalies before any intervention may prevent complications in embolization procedures (12) and in the placement of large access catheters, sheaths, and devices used for transcatheter interventions. The anomaly in this report is associated with a short radius course through the pelvis and would be likely at risk with larger, rigid devices. The venous and arterial anomalies would suggest that the etiology in this case is secondary to a segmental defect in the area of S-1 segment leading to paired venous drainage to the left sacrocardinal vein and atresia of the left common iliac artery. The result, a caudal ori-
gin of the external iliac bud and persistent left inferior vena cava. References 1. Mandell VS, Jaques PF, Delany DJ, Oberheu V. Persistent sciatic artery: clinical, embryologic, and angiographic features. AJR Am J Roentgenol 1985: 144:245–249. 2. Wu HY, Yang YJ, Lai CH, Roan JN, Luo CY, Kan CD. Bilateral persistent sciatic arteries complicated with acute left lower limb ischemia. J Formos Med Assoc 2007; 106:1038 –1042. 3. Greebe J. Congenital anomalies of the iliofemoral artery. J Cardiovasc Surg (Torino) 1977; 18:317–323. 4. Koyama T, Kawada T, Kitanaka Y. Congenital anomaly of the external iliac artery: a case report. J Vasc Surg 2003; 37:683– 685. 5. Tamisier D, Melki JP, Cormier JM. Congenital anomalies of the external iliac artery: case report and review of the literature. Ann Vasc Surg 1990; 4: 510 –514. 6. Harikrishnan S, Krishnamoorthy KM, Tharakan JM. Congenital bilateral apla-
7.
8.
9.
10.
11. 12.
sia of external iliac arteries. Int J Cardiol 2001; 80:85–86. Kawashima T, Sato K, Sasaki H. A human case of hypoplastic external iliac artery and its collateral pathways. Folia Morphol (Warsz) 2006; 65:157– 160. Development of the vasculature. In: Schoenwolf GC, ed. Larsen’s human embryology. 4th ed, Philadelphia, PA: Churchill Livingstone/Elsevier 2009; 385– 433. Cardiovascular system. In: Sadler TW, ed. Langman’s medical embryology. 10th ed. Philadelphia, PA: Lippincott Williams &Wilkins 2006; 159 – 194. Okamoto K, Wakebe T, Saiki K, Nagashima S. Consideration of the potential courses of the common iliac artery. Anat Sci Int 2005; 80:116 –119. Testut. Traite d’anatomie humanin. Paris, France: Octave Doin, ed. 1891; 149 –159. Hsu WC, Lim KE, Hsu YY. Inadvertent embolization of a persistent sciatic artery in pelvis trauma. Cardiovasc Intervent Radiol 2005; 28:518–520.
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Figure 3. (a) CT angiogram at the level or the aortic bifurcation. Note the persistent left infrarenal inferior vena aava (arrow). (b) CT angiogram at the level of the right iliac artery bifurcation. The left single iliac artery does not bifurcate (arrow). (c) CT angiogram at the level of the sacrum. The left single iliac artery has traveled posteriorly (arrow). The radiopaque catheter marks the left iliac vein. (d) CT angiogram at the level of the sacrum. The left single iliac artery (black arrow) has begun an anterolateral course. Note the superior gluteal artery (white arrow), which is shown longitudinally, and the inferior gluteal artery, which is just lateral and shown in cross section. The radiopaque catheter marks the left iliac vein. (e) CT angiogram at the level of the sacrum. The left single iliac artery (arrow) continues an anterior course lateral to the iliac vein and medial to the iliacus muscle. (f) CT angiogram at the level of the sacrum. The left single iliac artery (arrow) gives off a small branch that follows the path of the inferior epigastric artery initially but supplies branches to the obturator muscle.
Congenital Single, Pelvic Iliac Artery: A Case Report Daniel P. Link, MD, Armando S. Garza, BS, and Wayne L. Monsky, MD, PhD
Congenital vascular anomalies of pelvis and lower limb arteries are rare. During embryologic development, the sciatic artery represents the dominant supplier of blood to the lower limb. The external iliac and femoral arteries appear later in the process and take over as the sciatic artery regresses. Failure of the sciatic artery to regress creates a persistent sciatic artery malformation. Failure of the external iliac artery to properly bud may lead to similar vascular malformations. The authors present a patient with atresia of the left external iliac artery with an associated atresia of the left common iliac vein, duplication of the infrarenal inferior vena cava, and absence of the left S1 bony arch. The left-sided single iliac artery supplies both pelvic structures and the lower limb. The “pelvic” external iliac artery may result from embryologic budding at a lower segmental level than the usual fifth lumbar segmental artery. This combination of anomalies suggests an abnormality of segmentation on left at the first sacral level. J Vasc Interv Radiol 2009; 20:1231–1234 Abbreviation:
PSA ⫽ persistent sciatic artery
SIMILAR to cases of persistent sciatic artery (PSA) (1,2), congenital vascular anomalies of the pelvis and lower limb arteries are rare. Greeb (3) described only six iliofemoral anomalies in a series of 8,000 patients who underwent angiography. Atresia of the external iliac artery is considered to be extremely rare (4), with only a few cases reported in the literature (5–7). Congenital vascular anomalies of the pelvis and lower limb arteries may be symptomatic, causing symptoms of claudication or thrombosis (4); however, there are cases of asymptomatic anomalies that only become apparent at autopsy or imaging. Herein, we report a case of a single, left-sided iliac artery that follows a pelvic course and continues as a normal
From the Department of Radiology, Division of Vascular and Interventional Radiology, University of California, Davis, Medical Center, 4860 Y St, Ste 3400, Sacramento, CA 95817. Received August 27, 2008; final revision received May 23, 2009; accepted May 27, 2009. Address correspondence to D.P.L.; E-mail: [email protected] None of the authors have identified a conflict of interest. © SIR, 2009 DOI: 10.1016/j.jvir.2009.05.042
common femoral artery with subsequent normal branching.
CASE REPORT The patient, a 28-year-old man, was a passenger in a motor vehicle collision who was brought into our medical center emergently because of hypotension. He was successfully resuscitated with crystalloid boluses and 3 units of packed red blood cells. The pulse examination was normal. Computed tomography (CT) of the abdomen showed a small liver laceration and contrast medium extravasation thought to be secondary to mesenteric artery injury. Incidental notes were made regarding an absent leftsided sacral arch at S1 and the iliac artery anomaly. Subsequently, the patient underwent laparotomy and achieved hemostasis. The patient had bilateral nondisplaced pubic rami fractures without pelvic hematoma, a right displaced femoral fracture, and left forefoot injury. Arteriography of the left lower extremity was performed for the evaluation of his pelvic and lower extremity circulation before right femur fixation and forefoot repair. Arteriography revealed a normal abdominal aorta and no ab-
dominal or pelvic bleed. However, a single left iliac artery was noted having internal iliac artery branches including the anterior and posterior divisions (Figs 1, 2). This single left iliac artery descended into the pelvis and then coursed laterally and anteriorly, immediately proximal to the superior and inferior gluteal artery origins. This artery was continuous with the left common femoral artery, which branched to a normal deep and superficial artery that gave rise to a normal popliteal artery. The right iliac arteries and runoff were normal. There was normal three-vessel runoff to both feet. Review of the contrast-enhanced CT scan revealed the course of the left iliac artery and associated anomalies (Fig 3). In this patient, the right common iliac bifurcates at 6cm distal to the aortic bifurcation; however, the left common iliac artery persists as a single artery (Fig 3b). This single artery descends into the pelvis medial to the psoas muscle. This artery continues medially with the internal iliac vein, becoming the posterior division artery. Immediately before the superior and inferior gluteal artery takeoff, this large artery courses anteriolaterally
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Figure 1.
Congenital Single, Pelvic Iliac Artery
Arteriogram shows a single left iliac artery that takes an anomalous course.
from the obterator internus muscle and medial to the iliacus muscle, traveling lateral to a companion vein (Fig 3d, 3e). This artery enters the inguinal canal, forming a femoral artery at the level of the inferior epigastric and deep circumflex iliac arteries (Fig 3f). The common iliac vein is marked distally by an intravenous catheter. The vein follows the course of the artery and drains into a left-sided inferior vena cava and the left renal vein. No left common iliac vein is seen on the CT scan.
DISCUSSION The development of lower limb arteries begins as an extension of the paired dorsal aorta and intersegmental arteries during the 3rd week of gestation (8). These paired vessels have dorsal portions that supply the developing neural tube and ventral portions that supply muscle and skin; the ventral portions later develop into intercostal arteries in the thoracic region. In the lumbar area, the fifth pair of intersegmental arteries develops a distal bud. From this bud, the sacral segmental arteries develop along the axial (sciatic) artery of the lower limb. The first portion of this segmental artery develops as the internal iliac artery.
This axial artery is usually temporary, as the later-appearing external iliac artery is destined to take over the arterial supply to the leg by day 60 (8). The external artery bud usually arises from this 5th lumbar intersegmental branch (the umbilical artery) proximal to the axial artery origin (3). The sciatic artery begins to degenerate as the external iliac and femoral artery demand more flow as they supply the “rete femoralis,” a capillary network in the developing muscle mass of the thigh. With less flow, the embryonic axial artery (sciatic artery) fragments and persists as the popliteal, peroneal (fibular), and sciatic nerve arteries. The normal external iliac artery then gives rise to the common femoral artery and its bifurcation. The development of the venous system of the lower extremity is not well documented and is generally believed and assumed to be concurrent with arterial developmental anatomy. Veins and arteries develop as vascular pairs from capillary networks of the developing limb. Other reports of aberrant iliac artery anatomy did not comment on the venous structures. We believe our case is the first to describe such an association. The infrarenal inferior vena cava and left com-
September 2009
JVIR
mon iliac vein are most commonly derived from the sacrocardinal vein and interpostcardinal anasomosis, respectively (9). Persistent left infrarenal vena cava occurs when the interpostcardinal anastomosis fails. In these cases, the left limb drainage is through the postcardinal vein to the left renal vein. The absence of the left sacral arch in addition to the venous anomalies suggests that the arterial anomalies are congenital and not acquired through injury of the vessel. In addition, given the type of tissues involved, the anomaly is likely due to aberrancy in mesodermal development. Other reports did not comment on the bony structures. Tamisier et al (5) classified congenital malformations of the external iliac artery into three groups. Group 1 anomalies are represented by variance in origin or course of the artery. Group 2 anomalies are composed of hypolastic or atretic arteries that are compensated by a PSA. Group 3 arteries are similarly hypolastic; however, they are not compensated by a PSA. In the review by Tamisier et al (5), a case similar to the present case was classified in the group as anomaly of origin and course. This group of patients had normal femoral arteries. It is their origin and course that are abnormal. In the cases of external iliac arteries running a pelvic course (including this report), there is a constant relationship with the inferior and superior gluteal artery origins. The superior gluteal artery level seems to be the most caudal segmental (L5-S1). A normal femoral artery can only be formed from a bud arising cranial to this segment. In cases of PSA, the bud arises in the normal position but the axial artery persists because of flow demand. A high origin of the bud may yield an external iliac artery arising directly from the abdominal aorta (also classified as Tamisier group 1) (5). This present case resembles very closely the anatomy described by Okamoto et al (10) and Testut (11). Okamoto et al (10) believe that the anomalous external iliac bud in their case and similar cases probably occur when the internal iliac artery arises from a more distal segmental artery, derived from the median sacral artery. This
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Figure 2. Selective left common iliac artery digital arteriogram. (a) Right anterior oblique view of the anomalous vessel. (b) Left anterior oblique view of the anomalous vessel.
segment would be L5 or S1, explaining the position of the pelvic external iliac artery and sacral nerve. The anomalies in this case are interesting because, although rare, imaging in the medical population is finding anomalies at an increasing rate. Knowing about anomalies before any intervention may prevent complications in embolization procedures (12) and in the placement of large access catheters, sheaths, and devices used for transcatheter interventions. The anomaly in this report is associated with a short radius course through the pelvis and would be likely at risk with larger, rigid devices. The venous and arterial anomalies would suggest that the etiology in this case is secondary to a segmental defect in the area of S-1 segment leading to paired venous drainage to the left sacrocardinal vein and atresia of the left common iliac artery. The result, a caudal ori-
gin of the external iliac bud and persistent left inferior vena cava. References 1. Mandell VS, Jaques PF, Delany DJ, Oberheu V. Persistent sciatic artery: clinical, embryologic, and angiographic features. AJR Am J Roentgenol 1985: 144:245–249. 2. Wu HY, Yang YJ, Lai CH, Roan JN, Luo CY, Kan CD. Bilateral persistent sciatic arteries complicated with acute left lower limb ischemia. J Formos Med Assoc 2007; 106:1038 –1042. 3. Greebe J. Congenital anomalies of the iliofemoral artery. J Cardiovasc Surg (Torino) 1977; 18:317–323. 4. Koyama T, Kawada T, Kitanaka Y. Congenital anomaly of the external iliac artery: a case report. J Vasc Surg 2003; 37:683– 685. 5. Tamisier D, Melki JP, Cormier JM. Congenital anomalies of the external iliac artery: case report and review of the literature. Ann Vasc Surg 1990; 4: 510 –514. 6. Harikrishnan S, Krishnamoorthy KM, Tharakan JM. Congenital bilateral apla-
7.
8.
9.
10.
11. 12.
sia of external iliac arteries. Int J Cardiol 2001; 80:85–86. Kawashima T, Sato K, Sasaki H. A human case of hypoplastic external iliac artery and its collateral pathways. Folia Morphol (Warsz) 2006; 65:157– 160. Development of the vasculature. In: Schoenwolf GC, ed. Larsen’s human embryology. 4th ed, Philadelphia, PA: Churchill Livingstone/Elsevier 2009; 385– 433. Cardiovascular system. In: Sadler TW, ed. Langman’s medical embryology. 10th ed. Philadelphia, PA: Lippincott Williams &Wilkins 2006; 159 – 194. Okamoto K, Wakebe T, Saiki K, Nagashima S. Consideration of the potential courses of the common iliac artery. Anat Sci Int 2005; 80:116 –119. Testut. Traite d’anatomie humanin. Paris, France: Octave Doin, ed. 1891; 149 –159. Hsu WC, Lim KE, Hsu YY. Inadvertent embolization of a persistent sciatic artery in pelvis trauma. Cardiovasc Intervent Radiol 2005; 28:518–520.
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Figure 3. (a) CT angiogram at the level or the aortic bifurcation. Note the persistent left infrarenal inferior vena aava (arrow). (b) CT angiogram at the level of the right iliac artery bifurcation. The left single iliac artery does not bifurcate (arrow). (c) CT angiogram at the level of the sacrum. The left single iliac artery has traveled posteriorly (arrow). The radiopaque catheter marks the left iliac vein. (d) CT angiogram at the level of the sacrum. The left single iliac artery (black arrow) has begun an anterolateral course. Note the superior gluteal artery (white arrow), which is shown longitudinally, and the inferior gluteal artery, which is just lateral and shown in cross section. The radiopaque catheter marks the left iliac vein. (e) CT angiogram at the level of the sacrum. The left single iliac artery (arrow) continues an anterior course lateral to the iliac vein and medial to the iliacus muscle. (f) CT angiogram at the level of the sacrum. The left single iliac artery (arrow) gives off a small branch that follows the path of the inferior epigastric artery initially but supplies branches to the obturator muscle.