Correspondance : Maël Bellier, CHRU de Strasbourg Hautepierre, 1, avenue Molière, 67098 Strasbourg, France. [email protected] Reçu le 23 mars 2013 Accepté le 25 juin 2013 Disponible sur internet le 17 janvier 2014 ß 2013 Elsevier Masson SAS. Tous droits réservés http://dx.doi.org/10.1016/j.lpm.2013.06.030
Bilateral persistent sciatic artery diagnosed by multidetector-row CT angiography Persistance bilatérale de l’artère sciatique diagnostiquée par angioscanner multidétecteurs Persistent sciatic artery is a rare congenital malformation, in which the primitive vascular trunk persists as the main blood supply to the lower limbs. It can progress to an aneurysmal dilatation with a possible rupture or local neuromuscular compression. It can also result in lower limb ischemia due to thrombosis or distal embolism. The authors report a case of bilateral persistent sciatic artery with unilateral aneurysm. Case report A 50-year-old woman was admitted in vascular surgery unit in order to explore a pulsatile and painless left buttock mass. On physical examination, the mass measured about 5 6 cm. Lower limb pulses were present and normal. There were neither skin inflammatory signs nor trophicity abnormalities. Colour Doppler US image showed an aneurysm of a dilated artery between the muscles of the left gluteal region, with turbulent flow. This artery couldn’t be studied until its origin. Femoral arteries weren’t explored. The patient underwent a sixteen row-computed tomography (CT) angiography of her lower limbs. This examination was performed after intravenous
tome 43 > n83 > mars 2014
Letters to the editor
CHRU de Strasbourg, hôpital de Hautepierre, services de réanimation médicale et de radiologie, 67000 Strasbourg, France
administration of 100 ml of ionic contrast material with the rate of 3 ml/s. Arteries, from the abdominal aorta above the iliac bifurcation to the ankle, were evaluated. All data were evaluated on advantage workstation 4.4. Maximal intensity projection (MIP), multiplanar (MPR) and volume rendering (VR) reconstructions were created at the time of interpretation. Axial scans were used for correlation with 2D and 3D reconstructions. On the right side, there was an artery arising from the internal iliac artery and running in the thigh along the sciatic nerve. Femoral vessels were normal. It was an incomplete persistent sciatic artery variation (figure 1a–c). On the left side, there was a similar artery, but was more dilated and continued by the popliteal artery (complete persistent sciatic artery). A 37 mm aneurysm of this artery, developed in the gluteal region was noticed. The superficial femoral artery was thin and hypoplastic (figure 1a–c). Given the significant risk of embolic complications in the left lower limb and the risk of aneurismal rupture, the patient underwent a ligation of the sciatic artery and a left femoropopliteal bypass surgery. Several controls were performed by angio-CT showing patency of the bypass and exclusion of the aneurismal sac (figure 1d). Discussion Persistent sciatic artery is a rare embryological vascular anomaly that is reported in 0.025–0.04 of people [1]. Green PH reported the first case in 1832 [2]. It occurs on the right side in 50% of cases, the left in 20% and bilaterally in 30% like in our case [3]. The mean age at presentation has been found to be 45 years, with equal sex incidence [4]. During embryogenesis, the bud of the lower limb receives its arterial blood supply from the axial artery, which arises from the dorsal root of the umbilical artery. Later on, when the ventral root of this artery disappears, the external iliac artery develops and gives the femoral artery. Thereafter, the femoral artery bifurcates into superior communicating branch and descending geniculate artery. The latter joins the sciatic artery just above the knee. In the third month of embryonic development, the axial artery develops into the internal iliac artery and the sciatic artery involutes. Its upper part gives the superior and inferior gluteal arteries and its lower part gives the popliteal and fibular arteries [5]. Failure in development of the femoral system or involution of the axial system generates persistent sciatic artery [6]. Cases of the persistent sciatic artery are classically classified into complete and incomplete types [6]. Pillet J et al. suggested to subdivide the complete types into type 1 and type 2. In the first one, there is a normal superficial femoral artery. In the second one, the superficial femoral artery is either hypoplastic (type 2a) or completely absent (type 2b). In incomplete types, there is a normal superficial femoral artery. There can be the persistence of either the upper (type 3) or the lower (type 4)
325
Maël Bellier, Maleka Schenck, Max Guillot, Sophie Riehm, Francis Schneider
Letters to the editor
Figure 1 Row-computed tomography (CT) angiography of the lower limbs a and b: axial CT scans showing bilateral enlarged persistent sciatic arteries (SA) which are close to the sciatic nerves (SN). c: volume rendering (VR) reconstruction technique showing an incomplete right sciatic artery with a normal superficial femoral artery (RSFA) and a complete left sciatic artery with an aneurysm (A) and an hypoplastic superficial artery (LSFA). d: maximal intensity projection (MIP) reconstruction showing a patent left femoropopliteal bypass (FPB).
Figure 2 Schematic illustration of different types of persistent sciatic artery
326
In blue: ilio-femoral arteries; in red: sciatic artery. Complete type of sciatic artery can be associated with normal (type 1), hypoplastic (type 2a) or absent (type 2b) femoral artery. Incomplete type is due to the involution of the upper (type 3) or the lower (type 4) of the sciatic artery.
tome 43 > n83 > mars 2014
Conclusion Persistent sciatic artery is a very uncommon embryological vascular variant. A complete evaluation of the peripheral arterial system of the lower limb is essential before treatment decision. Our case illustrates how an accurate diagnosis and comprehensive evaluation of potential complications caused by a persistent sciatic artery can be done using multidetector CT angiography.
tome 43 > n83 > mars 2014
References [1]
Donovan DL, Sharp WV. Persistent sciatic artery: two cases reports with emphasis on embryologic development. Surgery 1984;95:363-6. [2] Green PH. On a new variety of the femoral artery. Lancet 1832;1:730-1. [3] SreeKumar KP, Prabhu NK, Moorthy S. Bilateral persistent sciatic artery: demonstration of the anomaly and its complications with intra arterial contrast enhanced spiral CT. Indian J Radiol Imaging 2004;14:205-7. [4] 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;106:1038-42. [5] Van Hooft IM, Zeebregts CJ, Van Sterkenburg SMM, De Vries WR, Reijnen MMPJ. The persistent sciatic artery. Eur J Vasc Endovasc Surg 2009; 37:585-91. [6] Wang B, Liu Z, Shen L. Bilateral persistent sciatic arteries complicated with chronic lower limb ischemia. Int J Surg Case Rep 2011;2:309-12. [7] Pillet J, Albaret P, Toulemonde JL, Cronier P, Raimbeau G, Chevalier JM. Tronc arteriel ischiopoplite, persistance de l’artère axiale. Bull Assoc Anat 1980;64:109-22. [8] Fung HS, Lau S, Chan MK, Tang KW, Cheung YL, Chan SC. Persistent sciatic artery complicated by aneurysm formation and thrombosis. Hong Kong Med J 2008;14:492-4. [9] Morinaga K, Kuma H, Kuroki M, Kusaba A, Okadome K, Miyazaki T et al. Occluded persistent sciatic artery. J Cardiovasc Surg (Torino) 1985;26:82-5. [10] Jung AY, Lee W, Chung JW, Song SY, Kim SJ, Ha J et al. Role of computed tomographic angiography in the detection and comprehensive evaluation of persistent sciatic artery. J Vasc Surg 2005;42:678-83.
Letters to the editor
Disclosure of interest: the authors declare that they have no conflicts of interest concerning this article.
Asma Zidi, Henda Neji, Saoussen Hantous-Zannad, Ines Baccouche, Khaoula Ben Miled-M’rad Abderrahmen Mami pneumology hospital, imaging department, 2080 Ariana, Tunisia Correspondence: Henda Neji, Abderrahmen Mami pneumology hospital, imaging department, Abderrahmen Mami Avenue, 2080 Arian, Tunisia. [email protected] Available online 17 December 2013 ß 2013 Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.lpm.2013.06.024
Déshydratation en cas de diarrhées chez des malades prenant des antihypertenseurs : apprendre aux patients à suspendre leurs médicaments Dehydration in case of diarrhea for people taking antihypertensives: How to teach the patients to stop their treatment
327
segments of the sciatic artery [7] (figure 2). In our case, there was type 3 on the right side and type 2a on the right side. Patients with persistent sciatic arteries are often asymptomatic until a complication develops. The diagnosis of persistent sciatic artery relies on patient presentation. When an aneurysm develops, patients may suffer from a painful and pulsatile gluteal mass, especially in the sitting position. They can also present with intermittent claudication, lower extremity ischemia or sciatic neuropathy caused by compression [8]. Aneurysm formation occurs in approximately 46% of cases. The high incidence of aneurysm formation is probably related to repeated external trauma since the persistent sciatic artery is in a relatively vulnerable anatomic position. The other causes behind its development include atherosclerosis, hypertension, congenital lack of arterial elastic tissue, and infection [6]. Conventional angiography was the imaging technique used to diagnose a persistent sciatic artery. It is now replaced by multidetector CT angiography, which has an increasing role in establishing the diagnosis. The characteristic findings include an enlargement of the iliac artery and/or hypoplastic superficial femoral artery terminating as small branches in the distal thigh [6]. Compared to conventional angiography, CT, a less invasive technique, allows a better study of popliteal and tibial vessels which can be difficult to visualise by the first technique leading to an erroneous diagnosis of occlusion [9]. It is also an advantageous mean to study the relationship between the persistent sciatic artery and the surrounding nerves, vessels, and musculoskeletal structures. These details help surgeons to plan their intervention [10]. Computed tomographic angiography and MRI can reveal aneurysm formation, precise the degree of intraluminal thrombosis, and look for associated venous anomalies. They can also demonstrate a totally occluded artery that cannot be seen on conventional angiography [6]. Treatment of persistent sciatic artery depends on 3 factors: anatomy of the sciatic artery, presence of occlusive anomalies and presence of an aneurysm. The management of the aneurysm can be surgical or endovascular [4]. Options for revascularisation of the lower extremities include graft interposition, a femoropopliteal bypass, and an iliac-persistent sciatic artery bypass. Even if there is neither aneurysm formation nor thromboembolic event, the patient should undergo a continued surveillance [6].
Bilateral persistent sciatic artery diagnosed by multidetector-row CT angiography Persistance bilatérale de l’artère sciatique diagnostiquée par angioscanner multidétecteurs Persistent sciatic artery is a rare congenital malformation, in which the primitive vascular trunk persists as the main blood supply to the lower limbs. It can progress to an aneurysmal dilatation with a possible rupture or local neuromuscular compression. It can also result in lower limb ischemia due to thrombosis or distal embolism. The authors report a case of bilateral persistent sciatic artery with unilateral aneurysm. Case report A 50-year-old woman was admitted in vascular surgery unit in order to explore a pulsatile and painless left buttock mass. On physical examination, the mass measured about 5 6 cm. Lower limb pulses were present and normal. There were neither skin inflammatory signs nor trophicity abnormalities. Colour Doppler US image showed an aneurysm of a dilated artery between the muscles of the left gluteal region, with turbulent flow. This artery couldn’t be studied until its origin. Femoral arteries weren’t explored. The patient underwent a sixteen row-computed tomography (CT) angiography of her lower limbs. This examination was performed after intravenous
tome 43 > n83 > mars 2014
Letters to the editor
CHRU de Strasbourg, hôpital de Hautepierre, services de réanimation médicale et de radiologie, 67000 Strasbourg, France
administration of 100 ml of ionic contrast material with the rate of 3 ml/s. Arteries, from the abdominal aorta above the iliac bifurcation to the ankle, were evaluated. All data were evaluated on advantage workstation 4.4. Maximal intensity projection (MIP), multiplanar (MPR) and volume rendering (VR) reconstructions were created at the time of interpretation. Axial scans were used for correlation with 2D and 3D reconstructions. On the right side, there was an artery arising from the internal iliac artery and running in the thigh along the sciatic nerve. Femoral vessels were normal. It was an incomplete persistent sciatic artery variation (figure 1a–c). On the left side, there was a similar artery, but was more dilated and continued by the popliteal artery (complete persistent sciatic artery). A 37 mm aneurysm of this artery, developed in the gluteal region was noticed. The superficial femoral artery was thin and hypoplastic (figure 1a–c). Given the significant risk of embolic complications in the left lower limb and the risk of aneurismal rupture, the patient underwent a ligation of the sciatic artery and a left femoropopliteal bypass surgery. Several controls were performed by angio-CT showing patency of the bypass and exclusion of the aneurismal sac (figure 1d). Discussion Persistent sciatic artery is a rare embryological vascular anomaly that is reported in 0.025–0.04 of people [1]. Green PH reported the first case in 1832 [2]. It occurs on the right side in 50% of cases, the left in 20% and bilaterally in 30% like in our case [3]. The mean age at presentation has been found to be 45 years, with equal sex incidence [4]. During embryogenesis, the bud of the lower limb receives its arterial blood supply from the axial artery, which arises from the dorsal root of the umbilical artery. Later on, when the ventral root of this artery disappears, the external iliac artery develops and gives the femoral artery. Thereafter, the femoral artery bifurcates into superior communicating branch and descending geniculate artery. The latter joins the sciatic artery just above the knee. In the third month of embryonic development, the axial artery develops into the internal iliac artery and the sciatic artery involutes. Its upper part gives the superior and inferior gluteal arteries and its lower part gives the popliteal and fibular arteries [5]. Failure in development of the femoral system or involution of the axial system generates persistent sciatic artery [6]. Cases of the persistent sciatic artery are classically classified into complete and incomplete types [6]. Pillet J et al. suggested to subdivide the complete types into type 1 and type 2. In the first one, there is a normal superficial femoral artery. In the second one, the superficial femoral artery is either hypoplastic (type 2a) or completely absent (type 2b). In incomplete types, there is a normal superficial femoral artery. There can be the persistence of either the upper (type 3) or the lower (type 4)
325
Maël Bellier, Maleka Schenck, Max Guillot, Sophie Riehm, Francis Schneider
Letters to the editor
Figure 1 Row-computed tomography (CT) angiography of the lower limbs a and b: axial CT scans showing bilateral enlarged persistent sciatic arteries (SA) which are close to the sciatic nerves (SN). c: volume rendering (VR) reconstruction technique showing an incomplete right sciatic artery with a normal superficial femoral artery (RSFA) and a complete left sciatic artery with an aneurysm (A) and an hypoplastic superficial artery (LSFA). d: maximal intensity projection (MIP) reconstruction showing a patent left femoropopliteal bypass (FPB).
Figure 2 Schematic illustration of different types of persistent sciatic artery
326
In blue: ilio-femoral arteries; in red: sciatic artery. Complete type of sciatic artery can be associated with normal (type 1), hypoplastic (type 2a) or absent (type 2b) femoral artery. Incomplete type is due to the involution of the upper (type 3) or the lower (type 4) of the sciatic artery.
tome 43 > n83 > mars 2014
Conclusion Persistent sciatic artery is a very uncommon embryological vascular variant. A complete evaluation of the peripheral arterial system of the lower limb is essential before treatment decision. Our case illustrates how an accurate diagnosis and comprehensive evaluation of potential complications caused by a persistent sciatic artery can be done using multidetector CT angiography.
tome 43 > n83 > mars 2014
References [1]
Donovan DL, Sharp WV. Persistent sciatic artery: two cases reports with emphasis on embryologic development. Surgery 1984;95:363-6. [2] Green PH. On a new variety of the femoral artery. Lancet 1832;1:730-1. [3] SreeKumar KP, Prabhu NK, Moorthy S. Bilateral persistent sciatic artery: demonstration of the anomaly and its complications with intra arterial contrast enhanced spiral CT. Indian J Radiol Imaging 2004;14:205-7. [4] 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;106:1038-42. [5] Van Hooft IM, Zeebregts CJ, Van Sterkenburg SMM, De Vries WR, Reijnen MMPJ. The persistent sciatic artery. Eur J Vasc Endovasc Surg 2009; 37:585-91. [6] Wang B, Liu Z, Shen L. Bilateral persistent sciatic arteries complicated with chronic lower limb ischemia. Int J Surg Case Rep 2011;2:309-12. [7] Pillet J, Albaret P, Toulemonde JL, Cronier P, Raimbeau G, Chevalier JM. Tronc arteriel ischiopoplite, persistance de l’artère axiale. Bull Assoc Anat 1980;64:109-22. [8] Fung HS, Lau S, Chan MK, Tang KW, Cheung YL, Chan SC. Persistent sciatic artery complicated by aneurysm formation and thrombosis. Hong Kong Med J 2008;14:492-4. [9] Morinaga K, Kuma H, Kuroki M, Kusaba A, Okadome K, Miyazaki T et al. Occluded persistent sciatic artery. J Cardiovasc Surg (Torino) 1985;26:82-5. [10] Jung AY, Lee W, Chung JW, Song SY, Kim SJ, Ha J et al. Role of computed tomographic angiography in the detection and comprehensive evaluation of persistent sciatic artery. J Vasc Surg 2005;42:678-83.
Letters to the editor
Disclosure of interest: the authors declare that they have no conflicts of interest concerning this article.
Asma Zidi, Henda Neji, Saoussen Hantous-Zannad, Ines Baccouche, Khaoula Ben Miled-M’rad Abderrahmen Mami pneumology hospital, imaging department, 2080 Ariana, Tunisia Correspondence: Henda Neji, Abderrahmen Mami pneumology hospital, imaging department, Abderrahmen Mami Avenue, 2080 Arian, Tunisia. [email protected] Available online 17 December 2013 ß 2013 Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.lpm.2013.06.024
Déshydratation en cas de diarrhées chez des malades prenant des antihypertenseurs : apprendre aux patients à suspendre leurs médicaments Dehydration in case of diarrhea for people taking antihypertensives: How to teach the patients to stop their treatment
327
segments of the sciatic artery [7] (figure 2). In our case, there was type 3 on the right side and type 2a on the right side. Patients with persistent sciatic arteries are often asymptomatic until a complication develops. The diagnosis of persistent sciatic artery relies on patient presentation. When an aneurysm develops, patients may suffer from a painful and pulsatile gluteal mass, especially in the sitting position. They can also present with intermittent claudication, lower extremity ischemia or sciatic neuropathy caused by compression [8]. Aneurysm formation occurs in approximately 46% of cases. The high incidence of aneurysm formation is probably related to repeated external trauma since the persistent sciatic artery is in a relatively vulnerable anatomic position. The other causes behind its development include atherosclerosis, hypertension, congenital lack of arterial elastic tissue, and infection [6]. Conventional angiography was the imaging technique used to diagnose a persistent sciatic artery. It is now replaced by multidetector CT angiography, which has an increasing role in establishing the diagnosis. The characteristic findings include an enlargement of the iliac artery and/or hypoplastic superficial femoral artery terminating as small branches in the distal thigh [6]. Compared to conventional angiography, CT, a less invasive technique, allows a better study of popliteal and tibial vessels which can be difficult to visualise by the first technique leading to an erroneous diagnosis of occlusion [9]. It is also an advantageous mean to study the relationship between the persistent sciatic artery and the surrounding nerves, vessels, and musculoskeletal structures. These details help surgeons to plan their intervention [10]. Computed tomographic angiography and MRI can reveal aneurysm formation, precise the degree of intraluminal thrombosis, and look for associated venous anomalies. They can also demonstrate a totally occluded artery that cannot be seen on conventional angiography [6]. Treatment of persistent sciatic artery depends on 3 factors: anatomy of the sciatic artery, presence of occlusive anomalies and presence of an aneurysm. The management of the aneurysm can be surgical or endovascular [4]. Options for revascularisation of the lower extremities include graft interposition, a femoropopliteal bypass, and an iliac-persistent sciatic artery bypass. Even if there is neither aneurysm formation nor thromboembolic event, the patient should undergo a continued surveillance [6].
