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Original Communication J Neurol (2008) 255:663–667 DOI 10.1007/s00415-008-0773-2 ORIGINAL COMMUNICATION Sarah Marti Rotational vertebral artery syndrome Stefan Hegemann Hans-Christian von Büdingen 3D kinematics of nystagmus suggest bilateral Ralf W. Baumgartner labyrinthine dysfunction Dominik Straumann ■ Received: 4 May 2007 Abstract Whether the rotational anterior inferior cerebellar arteries Received in revised form: 6 August 2007 vertebral artery syndrome (RVAS), were supplied by the basilar artery. Accepted: 9 October 2007 consisting of attacks of vertigo, The right PCoA originated from Published online: 18 February 2008 nystagmus and tinnitus elicited by the right internal carotid artery. head-rotation induced compression Color duplex sonography showed of the dominant vertebral artery severe reduction of diastolic blood (VA), reflects ischemic dysfunction flow velocities in the left VA during of uni- or bilateral peripheral or RVAS attacks. The nystagmus central vestibular structures, is still pattern can be best explained by debated. We report on a patient vectorial addition of 3D sensitivity with bilateral high-grade carotid vectors of stimulated right and left stenoses, in whom rightward head- anterior and horizontal semicir- rotation led to RVAS symptoms cular canals with slightly stronger including a prominent nystagmus. stimulation on the left side. We Three-dimensional kinematic hypothesize that in RVAS, compres- analysis of the nystagmus pattern, sion of dominant VA leads to acute recorded with search coils, revealed vertebrobasilar insufficiency with major downbeat nystagmus with bilateral, but asymmetric ischemia S. Marti, MD (౧) · H.-C. von Büdingen · minor horizontal and torsional of the superior labyrinth. With R. W. Baumgartner · D. Straumann components. Magnetic resonance regard to RVAS etiology, our case Dept. of Neurology Zurich University Hospital angiography demonstrated a illustrates a type of pure vascular Frauenklinikstrasse 26 hypoplastic right VA terminating RVAS. Severity of attacks markedly 8091 Zurich, Switzerland in the posterior inferior cerebellar decreased after successful bilateral Tel.: +41-44/255-3996 artery, a dominant left VA, and a carotid endarterectomy. Fax: +41-44/255-4380 E-Mail: [email protected] hypoplastic P1-segment of the left posterior cerebral artery (PCA) ■ Key words vertebral artery S. Hegemann Dept. of Otorhinolaryngology that was supplied by the left compression · vertigo · labyrinthine University Hospital Zurich posterior communicating artery ischemia · downbeat nystagmus Zurich, Switzerland (PCoA). The right PCA and both the rotational head movement, which leads to hemo- Introduction dynamic ischemia in the vertebrobasilar territory as the blood supply through the opposite hypoplastic VA Rotational vertebral artery syndrome (RVAS) is defined is not sufficient. VA compression is often enhanced by by recurrent attacks of vertigo, nystagmus, ataxia, and anatomical obstacles such as cervical spondylosis or tinnitus which are elicited by fierce head rotation [1–4]. muscular insertions [1, 2, 5]. JON 2773 The presumed mechanism leading to RVAS is transient However, whether the RVAS results from ischemia of compression of the dominant vertebral artery (VA) by uni- or bilateral labyrinthine structures or of the central 6663_667_Marti_JON_2773.indd63_667_Marti_JON_2773.indd 666363 114.05.20084.05.2008 114:02:424:02:42 UUhrhr 664 vestibular system remains unclear [2, 4]. Compression rotid endarterectomy (CEA), and RVAS did not improve of the dominant VA is expected to impair the blood sup- postoperatively. ply to the peripheral as well as the central parts of the Four months after CEA, the patient presented in vestibular system. On the other hand, clinical symptoms our hospital because of the RVAS attacks. Neurological and signs of this syndrome suggest primarily a peripheral examinations performed between the attacks were un- vestibular disorder. Indeed, recent ocular motor studies remarkable. The patient was repeatedly examined in the in patients with RVAS documented a mixed downward- challenging head position and the followings symptoms horizontal nystagmus pattern during the attacks, sug- and signs were always observed: A prominent downbeat gesting a dysfunction of the superior labyrinth1 on the nystagmus with – as seen from the patient – a left-beating side of VA compression [2–4]. But, since the labyrinth is horizontal and a counter-clockwise-beating torsional irrigated by the labyrinthine artery (LA, also known as component (i.e. upper eye poles rotating towards the the internal auditory artery), which is a branch of the left ear) occurred after a few seconds. The nystagmus anterior inferior cerebellar artery (AICA), and since persisted over the few seconds, during which the patient both AICA usually originate from the basilar artery (BA) was able to keep the challenging head position, and [6], one would expect that compression of the dominant disappeared within one or two seconds after the patient VA and the consecutive impairment of blood flow in the had moved the head into the straight-ahead position. BA leads to bilateral labyrinthine dysfunction. As shown in Fig. 1, magnetic resonance angiography In the present paper, we report on a patient with (MRA) demonstrated a dominant left VA and hypoplastic a well-documented vascular-type RVAS. Kinematic right VA that ended in the posterior inferior cerebellar analysis of three-dimensionally recorded nystagmus artery (PICA). The left posterior cerebral artery (PCA) revealed a strong upward and only minor horizontal was supplied mainly by the left posterior communicating and torsional drift components. The observed drift pat- artery (PCoA) due to hypoplasia of the precommunicat- tern most probably reflects a bilateral excitation of the ing (P1) segment of the left PCA, while the right PCA superior labyrinth with the stimulation being slightly was supplied by the basilar artery (BA). The right PCoA stronger on the side of the VA compression. This concept was supplied by the right ICA. Both anterior inferior of a bilateral, but asymmetric labyrinthine ischemia is cerebellar arteries (AICA) originated from the BA. plausible also in terms of the blood supply to the inner While the patient turned his head into the challeng- ear structures. ing position and experienced the described symptoms, insonation of the pars transversaria of the left VA with a handheld linear probe revealed a resistance profile with Case report absent diastolic blood flow velocities (Fig. 2A) compared to the normal blood flow velocities in the neutral head This 61 year old patient suffered from severe coronary position (Fig. 2B). artery disease and peripheral artery disease IIb. He An MRA in the challenging position of the head underwent coronary stenting several times, and aortic could not be performed, because the patient was unable valve replacement and coronary bypass surgery 3 years to tolerate the RVAS symptoms for more than a few ago. Vascular risk factors included hypertension, diabetes seconds. Cerebral MR imaging (MRI) showed general mellitus, cigarette smoking, and hypercholesterolemia. moderate brain atrophy, a few lacunar infarcts in both Over the past 12 months the patient had experienced hemispheres and, to a lesser degree, in the brainstem. the following symptoms that stereotypically occurred X-ray and computed tomography of the cervical spine when he turned his head more than 20° to the right showed mild osteochondrosis on segment C5/6, but no side: Dizziness, blurring of vision, unsteadiness of gait, osteophytes compressing the VA. pressure-like headaches on the right side, and a feeling About two months after our initial clinical examina- to start fainting. All symptoms ceased immediately tion, the patient experienced TIAs with weakness of upon moving the head back into the straight-ahead the right arm and face. CDS diagnosed now bilateral position. The provocative head position was not toler- high-grade carotid stenoses (left > 85%, right 70%) with ated for more than a few seconds. The symptoms did cross-flow to the left MCA through the ophthalmic and not occur in any other head position. A week after onset the anterior communicating arteries, and cross-flow to of the RVAS attacks, the patient experienced an attack the right MCA through the posterior communicating of amaurosis fugax. Color duplex sonography (CDS) artery (PCoA). He underwent left CEA without compli- revealed a high-grade stenosis at the origin of the right cation, but the characteristics of RVAS attacks did not internal carotid artery (ICA). He underwent right ca- change postoperatively. Stenting of the asymptomatic right carotid restenosis was performed without compli- 1 The superior labyrinth comprises the anterior and horizontal semi- cation five months later. CDS performed two days and circular canals and the utricle and is supplied by the anterior vestibular three months after right ICA stenting revealed normal artery (AVA), a branch of the internal auditory artery (LA). findings in the stented right carotid artery and a left 6663_667_Marti_JON_2773.indd63_667_Marti_JON_2773.indd 666464 114.05.20084.05.2008 114:02:424:02:42 UUhrhr 665 Fig. 1 Magnetic resonance angiogra- phy (MRA) of the cerebral arteries. The left vertebral artery (VA) is dominant; the right VA is hypoplastic and terminates in the posterior inferior cerebellar artery (PICA). The left posterior cerebral artery (PCA) is mainly irrigated by the left posterior communicating artery (PCoA); the right PCA and both anterior
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