Sciatic Neuropathy Associated With Persistent Sciatic Artery A. Dale
Andrew P. Gasecki, MD; George C. Ebers, MD, FRCPC; Vellet, MBBCh, FFRADD, FRCPC; Alastair Buchan, MD, FRCPC
\s=b\ Persistent sciatic artery is a congenital vascular anomaly of the arterial supply to the lower extremity. Thrombosis, distal embolization, aneurysmal dilatation, and rupture of this vessel with compression of the sciatic nerve have been recorded. Although rare in occurrence, complications of persistent sciatic artery should be included in the differential diagnosis of sciatic neuropathy. We present a case of an acute sciatic neuropathy secondary to pseudoaneurysm formation of a persistent sciatic artery. We demonstrate the diagnostic usefulness of magnetic resonance imaging. (Arch Neurol. 1992;49:967-968)
of the embryologically primitive sciatic Persistence is artery anomaly with about 70 reported the and anatomic literature. The incidence is a rare
in
cases
surgical
estimated to be only 0.025% to 0.01%.1,2 Reported compli¬ cations of persistent sciatic artery (PSA) include aneurys¬ mal dilatation, limb ischemia, rupture, thrombosis, distal embolization, or sciatic nerve compression.3 REPORT OF A CASE A 40-year-old right-handed white man was admitted to the neurology service with a foot drop. Ten years before this admis¬ sion, he had a venous ulcer posterior to the right medial malleolus, and a palpable pulsatile mass extending from the buttock down the posterior aspect of the thigh was found. At that time a
PSA was identified and the ulcer was attributed to associated varicosities. He was eventually treated with femoropopliteal by¬ pass followed by proximal and distal ligature of the sciatic artery. Six years later, after lifting a 30-kg object, he felt a sharp twinge in the right buttock and popliteal region and was readmitted. One or two days later, he became aware of a right foot drop and numbness along the outer aspect of the leg and the top of the foot. On examination, he was noted to have right lower extremity edema with numerous prominent varicosities. Pulses were present throughout and no masses were palpated from the but¬ tock down. No bruit was present. Motor strength was abnormal in the hamstring group (5-/5), tibialis anterior (4 + /5), and gastrocnemius (4+/5). Both foot inversion (5-/5) and eversión (4+ /5) were weak. Iliopsoas and gluteus médius strength were
Accepted for publication March 2, 1992. From the Department of Clinical Neurological Sciences, University Hospital, London, Ontario. Reprint requests to the Department of Clinical Neurological Sciences, University Hospital, 339 Windermere Rd, London, Ontario, Canada N6A 5A5 (Dr
Ebers).
Fig 1.—Magnetic resonance imaging of thrombosed right sciatic artery in its pelvic course. T,-weighted (SE; TR, TE; 600, 20) axial image ofec-
tatic sciatic artery demonstrates subacute thrombosis. The intraluminal thrombus is characterized by eccentric central deoxyhemoglobin (short arrow) surrounded by peripheral high-signal intensity methemoglobin (long arrow) within the ectatic artery (curved arrow).
preserved. Sensory examination revealed decreased light touch and pinprick sensation over the lateral calf, dorsal aspect of the foot and lateral three toes, and the plantar surface. The right an¬ kle jerk was absent. The patient was unable to walk on his heel or toes on the right side. An electromyogram was consistent with a sciatic neuropathy distal to the innervation of gluteal muscles and proximal to the innervation of the hamstring muscle group.
Although a Doppler study was inconclusive, a magnetic reso¬ nance imaging scan through the pelvis and proximal right thigh demonstrated evidence of a large ectatic PSA paralleling the sci¬ atic nerve throughout its course (Fig 1). The artery demonstrated evidence of thrombosis throughout, with a large pseudoaneu-
rysm arising from a discrete defect in the anterolateral wall of the sciatic artery within the proximal thigh (Fig 2). An angiogram showed an occluded proximal end of the PSA (Fig 3). As the pa¬ tient showed spontaneous improvement in muscle strength, evacuation of the hematoma was deferred.
Downloaded From: http://archneur.jamanetwork.com/ by a University of Iowa User on 05/24/2015
Fig 2.—Magnetic resonance imaging of pseudoaneurysm complicating sciatic artery. ,-weightedgradient-echo (SPGR; TR, TE, 22, 8) axial im¬ age through the middle of the thigh demonstrates a large thrombosed pseudoaneurysm (arrow) arising from the anterolateral aspect of the thrombosed sciatic artery (curved arrow). The defect in the arterial wall is evident (short arrow). There is a significant extrinsic mass effect on the adjacent sciatic nerve (long arrow).
COMMENT
Unexplained sciatic or buttock pain or a palpable "pul¬ sating" buttock mass should alert neurologists to the pos¬ sibility of the presence of PSA and its complications. Un¬ common, but pathognomonic, findings of an absent femoral pulse with strong popliteal and distal pulses should suggest PSA.3 This anomaly is almost always asso¬ ciated with limb atrophy or hypertrophy, leg varicosities, arteriovenous
malformations, mullerian agenesis with
solitary kidney,
a
and atherosclerosis.4
Persistent sciatic artery is a continuation of the inter¬ nal iliac artery and remains a major lower limb arterial supply until the femoral artery (from the umbilical ar¬ tery) reaches the distal part of the sciatic artery at the knee level during the third month of embryologie de¬ velopment. Subsequently, the PSA normally regresses to form the proximal part of the inferior gluteal artery, a portion of the popliteal artery, and a peroneal artery as its remnants.4,5 The most common complication of PSA is an aneurysmal degeneration that has been attributed to atherosclero¬ sis, direct frequent trauma to the buttock, or even recurrent hip motion.3,4 Thus, the vessel is particularly prone to rup¬ ture or thrombosis. The mechanism of injury with the pseudoaneurysm formation in our case is not entirely clear but a combination of factors described may play a role. Doppler ultrasound may be helpful in identification of the
Fig
3.—Pelvic arteriogram.
Oblique digital subtraction pelvic arterioright persistent sciatic artery just
gram demonstrates obstruction of the
distal to its origin (arrow).
PSA
or
its
complications.1 Magnetic
provides
resonance
imaging,
clear-cut anatomic delineation of the however, abnormality, as well as supervening complications such as those mentioned in this case. The current treatment consists of the femoropopliteal graft and PSA ligation in a symptomatic patient. Aneurysmectomy of PSA has been suggested, although not recom¬ mended, for aneurysms within the sciatic nerve sheath to avoid nerve injury.2 Patients with PSA aneurysms may present with sciatica and even undergo disk surgery.2 Disk disease was initially suspected in our patient particularly because of onset of pain after lifting. Therefore, awareness of the presence of this abnormality is important to neurol¬ ogists and should be included in the differential diagnosis of sciatic nerve syndromes. a
References
Youngson CG, Taylor B, Rankin R, Heimbecker artery: a case report. Can J Surg. 1980;23:466-467. 1.
RO. Persistent sciatic
2. Freeman MP, Tisnado J, Cho SR. Persistent sciatic artery: report of three cases and literature review. Br J Radiol. 1986;59:217-223. 3. Martin KW, Hyde GL, McCready RA, Hull DA. Sciatic artery aneurysms: report of three cases and review of the literature. J Vasc Surg. 1986;4:365371.
4. Becquemin JP, Gaston A, Coubret P, Uzzan C, Melliere D. Aneurysm of persistent sciatic artery: report of a case treated by endovascular occlusion and femoropopliteal bypass. Surgery. 1985;3:605-611. 5. Mandell VS, Jaques PF, Delany DJ, Oberheu V. Persistent sciatic artery: clinical embryologic and angiographic features. AJR Am J Roentgenol. 1985; 144:245-249.
Downloaded From: http://archneur.jamanetwork.com/ by a University of Iowa User on 05/24/2015
Andrew P. Gasecki, MD; George C. Ebers, MD, FRCPC; Vellet, MBBCh, FFRADD, FRCPC; Alastair Buchan, MD, FRCPC
\s=b\ Persistent sciatic artery is a congenital vascular anomaly of the arterial supply to the lower extremity. Thrombosis, distal embolization, aneurysmal dilatation, and rupture of this vessel with compression of the sciatic nerve have been recorded. Although rare in occurrence, complications of persistent sciatic artery should be included in the differential diagnosis of sciatic neuropathy. We present a case of an acute sciatic neuropathy secondary to pseudoaneurysm formation of a persistent sciatic artery. We demonstrate the diagnostic usefulness of magnetic resonance imaging. (Arch Neurol. 1992;49:967-968)
of the embryologically primitive sciatic Persistence is artery anomaly with about 70 reported the and anatomic literature. The incidence is a rare
in
cases
surgical
estimated to be only 0.025% to 0.01%.1,2 Reported compli¬ cations of persistent sciatic artery (PSA) include aneurys¬ mal dilatation, limb ischemia, rupture, thrombosis, distal embolization, or sciatic nerve compression.3 REPORT OF A CASE A 40-year-old right-handed white man was admitted to the neurology service with a foot drop. Ten years before this admis¬ sion, he had a venous ulcer posterior to the right medial malleolus, and a palpable pulsatile mass extending from the buttock down the posterior aspect of the thigh was found. At that time a
PSA was identified and the ulcer was attributed to associated varicosities. He was eventually treated with femoropopliteal by¬ pass followed by proximal and distal ligature of the sciatic artery. Six years later, after lifting a 30-kg object, he felt a sharp twinge in the right buttock and popliteal region and was readmitted. One or two days later, he became aware of a right foot drop and numbness along the outer aspect of the leg and the top of the foot. On examination, he was noted to have right lower extremity edema with numerous prominent varicosities. Pulses were present throughout and no masses were palpated from the but¬ tock down. No bruit was present. Motor strength was abnormal in the hamstring group (5-/5), tibialis anterior (4 + /5), and gastrocnemius (4+/5). Both foot inversion (5-/5) and eversión (4+ /5) were weak. Iliopsoas and gluteus médius strength were
Accepted for publication March 2, 1992. From the Department of Clinical Neurological Sciences, University Hospital, London, Ontario. Reprint requests to the Department of Clinical Neurological Sciences, University Hospital, 339 Windermere Rd, London, Ontario, Canada N6A 5A5 (Dr
Ebers).
Fig 1.—Magnetic resonance imaging of thrombosed right sciatic artery in its pelvic course. T,-weighted (SE; TR, TE; 600, 20) axial image ofec-
tatic sciatic artery demonstrates subacute thrombosis. The intraluminal thrombus is characterized by eccentric central deoxyhemoglobin (short arrow) surrounded by peripheral high-signal intensity methemoglobin (long arrow) within the ectatic artery (curved arrow).
preserved. Sensory examination revealed decreased light touch and pinprick sensation over the lateral calf, dorsal aspect of the foot and lateral three toes, and the plantar surface. The right an¬ kle jerk was absent. The patient was unable to walk on his heel or toes on the right side. An electromyogram was consistent with a sciatic neuropathy distal to the innervation of gluteal muscles and proximal to the innervation of the hamstring muscle group.
Although a Doppler study was inconclusive, a magnetic reso¬ nance imaging scan through the pelvis and proximal right thigh demonstrated evidence of a large ectatic PSA paralleling the sci¬ atic nerve throughout its course (Fig 1). The artery demonstrated evidence of thrombosis throughout, with a large pseudoaneu-
rysm arising from a discrete defect in the anterolateral wall of the sciatic artery within the proximal thigh (Fig 2). An angiogram showed an occluded proximal end of the PSA (Fig 3). As the pa¬ tient showed spontaneous improvement in muscle strength, evacuation of the hematoma was deferred.
Downloaded From: http://archneur.jamanetwork.com/ by a University of Iowa User on 05/24/2015
Fig 2.—Magnetic resonance imaging of pseudoaneurysm complicating sciatic artery. ,-weightedgradient-echo (SPGR; TR, TE, 22, 8) axial im¬ age through the middle of the thigh demonstrates a large thrombosed pseudoaneurysm (arrow) arising from the anterolateral aspect of the thrombosed sciatic artery (curved arrow). The defect in the arterial wall is evident (short arrow). There is a significant extrinsic mass effect on the adjacent sciatic nerve (long arrow).
COMMENT
Unexplained sciatic or buttock pain or a palpable "pul¬ sating" buttock mass should alert neurologists to the pos¬ sibility of the presence of PSA and its complications. Un¬ common, but pathognomonic, findings of an absent femoral pulse with strong popliteal and distal pulses should suggest PSA.3 This anomaly is almost always asso¬ ciated with limb atrophy or hypertrophy, leg varicosities, arteriovenous
malformations, mullerian agenesis with
solitary kidney,
a
and atherosclerosis.4
Persistent sciatic artery is a continuation of the inter¬ nal iliac artery and remains a major lower limb arterial supply until the femoral artery (from the umbilical ar¬ tery) reaches the distal part of the sciatic artery at the knee level during the third month of embryologie de¬ velopment. Subsequently, the PSA normally regresses to form the proximal part of the inferior gluteal artery, a portion of the popliteal artery, and a peroneal artery as its remnants.4,5 The most common complication of PSA is an aneurysmal degeneration that has been attributed to atherosclero¬ sis, direct frequent trauma to the buttock, or even recurrent hip motion.3,4 Thus, the vessel is particularly prone to rup¬ ture or thrombosis. The mechanism of injury with the pseudoaneurysm formation in our case is not entirely clear but a combination of factors described may play a role. Doppler ultrasound may be helpful in identification of the
Fig
3.—Pelvic arteriogram.
Oblique digital subtraction pelvic arterioright persistent sciatic artery just
gram demonstrates obstruction of the
distal to its origin (arrow).
PSA
or
its
complications.1 Magnetic
provides
resonance
imaging,
clear-cut anatomic delineation of the however, abnormality, as well as supervening complications such as those mentioned in this case. The current treatment consists of the femoropopliteal graft and PSA ligation in a symptomatic patient. Aneurysmectomy of PSA has been suggested, although not recom¬ mended, for aneurysms within the sciatic nerve sheath to avoid nerve injury.2 Patients with PSA aneurysms may present with sciatica and even undergo disk surgery.2 Disk disease was initially suspected in our patient particularly because of onset of pain after lifting. Therefore, awareness of the presence of this abnormality is important to neurol¬ ogists and should be included in the differential diagnosis of sciatic nerve syndromes. a
References
Youngson CG, Taylor B, Rankin R, Heimbecker artery: a case report. Can J Surg. 1980;23:466-467. 1.
RO. Persistent sciatic
2. Freeman MP, Tisnado J, Cho SR. Persistent sciatic artery: report of three cases and literature review. Br J Radiol. 1986;59:217-223. 3. Martin KW, Hyde GL, McCready RA, Hull DA. Sciatic artery aneurysms: report of three cases and review of the literature. J Vasc Surg. 1986;4:365371.
4. Becquemin JP, Gaston A, Coubret P, Uzzan C, Melliere D. Aneurysm of persistent sciatic artery: report of a case treated by endovascular occlusion and femoropopliteal bypass. Surgery. 1985;3:605-611. 5. Mandell VS, Jaques PF, Delany DJ, Oberheu V. Persistent sciatic artery: clinical embryologic and angiographic features. AJR Am J Roentgenol. 1985; 144:245-249.
Downloaded From: http://archneur.jamanetwork.com/ by a University of Iowa User on 05/24/2015
