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Vertebral Artery Embolism Post Subclavian Artery Injury with Occipital Lobe Infarction
Eur J Vasc Endovasc Surg 19, 85–86 (2000) doi:10.1053/ejvs.1999.0904, available online at http://www.idealibrary.com on
LESSON OF THE MONTH
Vertebral Artery Embolism Post Subclavian Artery Injury with Occipital Lobe Infarction R. Jithoo∗1, S. S. Nadvi1 and J. V. Robbs2 Departments of 1Neurosurgery and 2General Surgery, University of Natal Medical School and Wentworth Hospital, Durban, South Africa
Introduction Posterior-circulation infarction is commonly due to atherosclerosis or embolic cardiac phenomena. This clinical report illustrates a rare case of occipital-lobe infarction following repair of the subclavian artery due to penetrating injury. This entity has not been previously reported.
no intimal tears, false aneurysms noted. The arterial circulation also from a developmental viewpoint. managed conservatively and made covery.
or plaques were appeared normal The patient was an uneventful re-
Discussion Case Report A twenty-six-year-old male sustained a stab wound to the right subclavian artery. He underwent emergency exploration of the subclavian artery, with primary repair being performed by a vascular surgeon. The injury was at the junction of the second and third parts of the subclavian artery. The patient presented at hospital two weeks after discharge complaining of severe occipital headaches and was referred to the neurosurgical service. Clinical examination was normal except for a left homonymous hemianopia. No bruits were auscultated over the repair site or over the vertebral or carotid arteries. Computerised tomography (CT) (Fig. 1) revealed a haemorrhagic infarct of the right occipital lobe in the distribution of the posterior cerebral artery. Magnetic-resonance angiography (MRA) was performed to assess the patency and status of the vertebral and carotid arterial circulation and these were normal. (Fig. 2) Specifically, ∗ Please address all correspondence to: R. Jithoo, Department of Neurosurgery, Wentworth Hospital, P/Bag Jacobs 4026, Durban, South Africa. 1078–5884/00/010085+02 $35.00/0 2000 Harcourt Publishers Ltd.
Penetrating trauma causing posterior-cerebral-circulation infarction is rare. The mechanism postulated is intra-arterial embolism following upon penetrating trauma. Intra-arterial embolism is, however, well documented and commonly seen as a consequence of vertebral artery occlusive disease.1,2 Cerebral infarction has multifactorial predisposing factors including genetic, anatomical and environmental, and is dependent
Fig. 1. CT scan showing a right occipital-lobe haemorrhagic infarction in the distribution of the posterior cerebral artery.
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basilar artery. Admixture of flow is not complete. Smith et al. showed parallel flow in 80% of patients and spiral flow in 20% of cases.5 The clinical significance may be that one may attribute sidedness to a single vertebral-artery source. Posterior-circulation infarction following penetrating trauma is rare and requires a high index of suspicion. Careful clinical examination including visual fields should be performed. Cerebral imaging by computerised tomography and angiography is required to confirm the diagnosis. Knowledge of vascular anatomy and flow patterns may aid in management. In view of the above, we recommend that any patient presenting with neurological signs following penetrating injury to the subclavian artery should be screened for infarction by CT scan followed by angiography. Fig. 2. Normal magnetic resonance angiogram of the posterior circulation.
upon collateral flow to the ischaemic area. Primary collateral vessels respond quickly to low perfusion pressure with simple reversal of flow.3 Secondary collateral vessels require time for recruitment and are acquired in response to the stress of chronic hypoperfusion. Collateral pathways protect perfusion in the event of severe stenosis or occlusion of a feeding artery. Decreased size and patency of collaterals therefore constitute risk factors for cerebral infarction. A balanced, complete (all arterial segments patent and of low resistance) circle of Willis occurs in only 18% of the general population, although the influence of the “completeness” of the circle of Willis on cerebral infarction is not known. Four-vessel angiography or MRA may be utilised to image the cerebral circulation. Vertebral artery flow is known to exhibit spiral and parallel patterns in the
Eur J Vasc Endovasc Surg Vol 19, January 2000
Acknowledgement We thank Mrs. M. du Plooy for assistance with the preparation of the manuscript.
References 1 Caplan LR, Amarenco P, Rosengart A et al. Embolism from vertebral artery origin occlusive disease. Neurology 1992; 42: 1505– 1512. 2 Koroshetz WJ, Ropper AH. Artery to artery embolism causing stroke in the posterior circulation. Neurology 1987; 32: 292–295. 3 Schomer DF, Marks MP, Steinberg GK et al. The anatomy of the posterior communicating artery as a risk factor for ischemic cerebral infarction. N Eng J Med 1994; 330: 1565–1570. 4 Greenberg MS, Ed. In: Handbook of Neurosurgery 4th Edition, Florida U.S.A.: Greenberg Graphics, Inc. 1997: 51. 5 Smith AS, Bellon JR. Parallel and spiral flow patterns of vertebral artery contributions to the basilar artery. AM J Neuroradiology 1998; 16: 1587–1591. Accepted 28 April 1999
LESSON OF THE MONTH
Vertebral Artery Embolism Post Subclavian Artery Injury with Occipital Lobe Infarction R. Jithoo∗1, S. S. Nadvi1 and J. V. Robbs2 Departments of 1Neurosurgery and 2General Surgery, University of Natal Medical School and Wentworth Hospital, Durban, South Africa
Introduction Posterior-circulation infarction is commonly due to atherosclerosis or embolic cardiac phenomena. This clinical report illustrates a rare case of occipital-lobe infarction following repair of the subclavian artery due to penetrating injury. This entity has not been previously reported.
no intimal tears, false aneurysms noted. The arterial circulation also from a developmental viewpoint. managed conservatively and made covery.
or plaques were appeared normal The patient was an uneventful re-
Discussion Case Report A twenty-six-year-old male sustained a stab wound to the right subclavian artery. He underwent emergency exploration of the subclavian artery, with primary repair being performed by a vascular surgeon. The injury was at the junction of the second and third parts of the subclavian artery. The patient presented at hospital two weeks after discharge complaining of severe occipital headaches and was referred to the neurosurgical service. Clinical examination was normal except for a left homonymous hemianopia. No bruits were auscultated over the repair site or over the vertebral or carotid arteries. Computerised tomography (CT) (Fig. 1) revealed a haemorrhagic infarct of the right occipital lobe in the distribution of the posterior cerebral artery. Magnetic-resonance angiography (MRA) was performed to assess the patency and status of the vertebral and carotid arterial circulation and these were normal. (Fig. 2) Specifically, ∗ Please address all correspondence to: R. Jithoo, Department of Neurosurgery, Wentworth Hospital, P/Bag Jacobs 4026, Durban, South Africa. 1078–5884/00/010085+02 $35.00/0 2000 Harcourt Publishers Ltd.
Penetrating trauma causing posterior-cerebral-circulation infarction is rare. The mechanism postulated is intra-arterial embolism following upon penetrating trauma. Intra-arterial embolism is, however, well documented and commonly seen as a consequence of vertebral artery occlusive disease.1,2 Cerebral infarction has multifactorial predisposing factors including genetic, anatomical and environmental, and is dependent
Fig. 1. CT scan showing a right occipital-lobe haemorrhagic infarction in the distribution of the posterior cerebral artery.
86
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basilar artery. Admixture of flow is not complete. Smith et al. showed parallel flow in 80% of patients and spiral flow in 20% of cases.5 The clinical significance may be that one may attribute sidedness to a single vertebral-artery source. Posterior-circulation infarction following penetrating trauma is rare and requires a high index of suspicion. Careful clinical examination including visual fields should be performed. Cerebral imaging by computerised tomography and angiography is required to confirm the diagnosis. Knowledge of vascular anatomy and flow patterns may aid in management. In view of the above, we recommend that any patient presenting with neurological signs following penetrating injury to the subclavian artery should be screened for infarction by CT scan followed by angiography. Fig. 2. Normal magnetic resonance angiogram of the posterior circulation.
upon collateral flow to the ischaemic area. Primary collateral vessels respond quickly to low perfusion pressure with simple reversal of flow.3 Secondary collateral vessels require time for recruitment and are acquired in response to the stress of chronic hypoperfusion. Collateral pathways protect perfusion in the event of severe stenosis or occlusion of a feeding artery. Decreased size and patency of collaterals therefore constitute risk factors for cerebral infarction. A balanced, complete (all arterial segments patent and of low resistance) circle of Willis occurs in only 18% of the general population, although the influence of the “completeness” of the circle of Willis on cerebral infarction is not known. Four-vessel angiography or MRA may be utilised to image the cerebral circulation. Vertebral artery flow is known to exhibit spiral and parallel patterns in the
Eur J Vasc Endovasc Surg Vol 19, January 2000
Acknowledgement We thank Mrs. M. du Plooy for assistance with the preparation of the manuscript.
References 1 Caplan LR, Amarenco P, Rosengart A et al. Embolism from vertebral artery origin occlusive disease. Neurology 1992; 42: 1505– 1512. 2 Koroshetz WJ, Ropper AH. Artery to artery embolism causing stroke in the posterior circulation. Neurology 1987; 32: 292–295. 3 Schomer DF, Marks MP, Steinberg GK et al. The anatomy of the posterior communicating artery as a risk factor for ischemic cerebral infarction. N Eng J Med 1994; 330: 1565–1570. 4 Greenberg MS, Ed. In: Handbook of Neurosurgery 4th Edition, Florida U.S.A.: Greenberg Graphics, Inc. 1997: 51. 5 Smith AS, Bellon JR. Parallel and spiral flow patterns of vertebral artery contributions to the basilar artery. AM J Neuroradiology 1998; 16: 1587–1591. Accepted 28 April 1999