Acta Neurochir https://doi.org/10.1007/s00701-017-3367-x CASE REPORT - VASCULAR Vertebrobasilar dolichoectasia causing homonymous hemianopia: a case report and review of the literature Ladina Greuter 1 & Jean-Yves Fournier 1 Received: 5 October 2017 / Accepted: 17 October 2017 # Springer-Verlag GmbH Austria 2017 Abstract A 73-year-old man was diagnosed with an incidental finding of right homonymous hemianopia and presyncopal spells. Magnetic resonance imaging revealed a vertebrobasilar dolichoectasia (VBD) with compression of the left optic tract. VBD is defined as an elongation and dilatation of the basilar artery. Only a few cases have been described in the literature of VBD causing optic tract compression. So far no treatment option has been described for these cases, while surgical options exist for compressions of other cranial nerves, most commonly the trigeminal nerve. VBD can further cause stroke or cerebral and subarachnoid bleeding. Keywords Vertebrobasilar dolichoectasia . Hemianopsia . Optic tract compression Background Vertebrobasilar dolichoectasia (VBD) describes the entity of an elongated and dilated basilar artery. Smoker et al. [20, 21] defined a diameter of >4.5 mm and an elongation with the basilar artery lateral to the margin of the clivus, dorsum sellae or a bifurcation above the suprasellar cistern as dolichoectatic artery. Incidence varies and ranges from 0.06 to 5.8% [5, 12]. VBD clinically causes stroke, brain stem compression or haemorrhage as well as hydrocephalus [5, 23]. Five-year risk for ischaemic stroke, haemorrhage and progressive brainstem * Jean-Yves Fournier Jean-yves.fournier@kssg.ch 1 Department of Neurosurgery, Cantonal Hospital St. Gallen, Rorschacherstr. 94, 9007 St. Gallen, Switzerland compression were estimated at 17.6%, 4.7% and 10.3% respectively [23]. Due to the anatomical situation, VBD mostly causes trigeminal neuralgia or hemifacial spasm with compression of cranial nerves V or VII respectively [24]. Less often, cases with compression of cranial nerves IV, VI, III and the optic tract have been described [2, 7, 8, 10, 11, 13, 15, 19, 24]. Optic tract compression presenting with homonymous hemianopia due to VBD has only been described in six case reports (Table 1). However, more cases of anterior visual pathway compression exist due to an elongation of the carotid artery [2, 6–8, 15, 19]. Two cases which were reported by Purvin et al. [19] and Bloch et al. [2] as early as 1980 describe compression of the optic chiasm resulting in bi-temporal hemianopia. One case describes compression of the third ventricle, resulting in left homonymous hemianopia [6]. However, no compression anterior to the chiasm has been described due to VBD. Pathophysiology of VBD is assumed to be influenced by general vascular risk factors and hence remodelling of the tunica media; in some cases, abdominal aortic ectasia can co-exist due to a similar pathophysiology [17, 18]. Treatment of patients with VBD remains mostly unclear, lacking any randomised studies or treatment recommendations. Some studies suggest the use of antiplatelet agents or anticoagulants, as ischaemic stroke was shown to occur more frequently than bleeding and a treatment of hypertension, if present [12, 22–24]. Microvascular decompression in VBD is used for trigeminal neuralgia and hemifacial spasm; however, it has never been described in cases of compression of other cranial nerves [1, 4]. Matsumoto et al. [14] described two cases with VBD where the change of haemodynamics with a bypass was successful. Most of the patients with visual symptoms due to VBD received conservative treatment, and most of the Acta Neurochir Table 1 Overview of cases in the literature describing postchiasmal optic pathway compression syndromes due to VBD Author year Symptoms Perimetry Site of compression Associated pathologies Treatment Holmes 2017 [8] Asymptomatic incidental finding Inferior left homonymous quadrantopia Glosso-pharyngeal neuralgia Medication for glosso-pharyngeal neuralgia Mortzos 2013 [15] Visual loss, reading difficulty Right homonymous hemianopia Left optic neuropathy due to secondary displacement of ICA Untreated Purvin 2004 [19] Purvin 2004 [19] – bitemporal heminaopia Right optic tract and chiasm, displacement of lower brainstem Left optic tract, displacement of internal carotid artery (ICA) optic chiasm Ataxia – Asymptomatic Left homonymous hemianopia Left homonymous hemianopia Left homonymous hemianopia, bilateral optic nerve head pallor Left homonymous hemianopia Right optic tract – – Right optic tract Died of stroke – Right optic tract – Untreated Right optic tract None – Bitemporal hemianopia Optic chiasm None – Left homonymous hemianopia Third ventricle – – Purvin 2004 [19] – Guirgis 2001 [7] Progressive vision loss Bloch 1980 [2] Sudden onset of pain behind right eye, hazy vision Headache, memory problems – Bloch 1980 [2] Greitz 1954 [6] - not described reported cases have not described any progression; however, follow-up times are not consistent [7, 8, 15, 19]. Case We present the case of a 73-year-old man who had an incidental finding of right homonymous hemianopia during regular ophthalmologic check-ups for a known stable glaucoma. His past medical history was positive for coronary heart disease, for which he was medicated with acetylsalicylic acid, diabetes mellitus type 2 and a prostate carcinoma T2c N0 M0 (Gleason 7). Additionally he presented with presyncopal spells that motivated a brain magnetic resonance imaging (MRI) including an MR angiogram, which showed a VBD compression of the left optic tract (Fig. 1). The clinical picture is well explained due to the anatomic structure of the VBD and remained stable so far. No surgical or interventional therapy was carried out and the patient was already on therapy with an antiplatelet agent due to coronary artery disease. Acta Neurochir Fig. 1 MRI scan of our patient (sagittal and coronal views) showing the VBD with compression of the optic tract Discussion Searching the literature, we have only found six other cases describing direct optic tract compression, two cases with chiasmal compression and one additional case describing ventricular compression due to VBD; the first case was published in 1954. In a case series published by Purvin et al. [19], only three of ten cases—all causing anterior optic pathway compression—were due to VBD; the other cases reported compression due to an ectatic carotid artery. Two cases in the series caused optic tract compression and consequent homonymous hemianopia, while one case of VBD had compression of the optic chiasm with consecutive bi-temporal hemianopia. The duration of symptoms vary with only one of them reporting incidental finding of VBD [8]. Diagnostics in our patient included an MRI without contrast, which already lead to the diagnosis of VBD. Two of the reports were published before 1980 when MRI was not a widely available diagnostic tool, so they based their diagnosis on encephalography and angiography [2, 6]. Of the remaining four papers, half used non-contrast MRI, while the other half used additional MR angiography or even conventional angiography [7, 8, 15, 19]. However, Smoker et al. [20, 21] based their diagnostic definition of VBD on MRI imaging, hence this seems to be a sufficient tool to investigate patients for VBD. Some reports described a stable clinical follow-up but did not mention whether the patients were treated with antiplatelet or anticoagulation therapy [8, 15, 19]. Two studies stated clearly that the prognosis was unclear and surgery was not an available option [7, 15]. One study mentioned surgery as a treatment option in case of disease progression, but did not give any further details concerning the surgical procedure considered [8]. We did not consider any surgical treatment due to the anatomical situation with perforating arteries of the basilar arty to the pons, which could have been injured by surgery, causing major brainstem infarction, and the difficult access route did not seem to make it feasible to offer the patient any surgical treatment. However, surgery has been shown to be successful in trigeminal neuralgia due to VBD. Besides the classical insertion of Dacron or Teflon patches, various other techniques have been described, including the use of a bent burr-hole plate or traction of the VBD with a Gore-Tex sling to treat the vesselnerve-conflict [1, 3, 9, 16]. Conclusions VBD is a rare differential diagnosis in trigeminal neuralgia or visual field deficits and susceptive patients should be scanned for VBD. So far no guidelines exist concerning treatment of VBD causing homonymous hemianopia as only a handful of cases have been reported. 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