The case regards a sixty-year-old male of Indian-Surinamese origin with a high cardiovascular risk profile, based on type II diabetes mellitus, hypertension, coronary artery disease and a positive family history of cardiovascular disease. The patient primarily presented with complaints of atypical paroxysmal headaches. A few years later, there were progressive complaints of transient vertigo, tinnitus, and right homonymous hemianopsia upon turning his head to the left. These complaints led to nausea, an unstable gait and impeded the patient from participation in traffic. There were no episodes of loss of consciousness. After returning his head to a neutral position it took fifteen seconds before the right field of view was restored.
Physical examination with neutral position of the head revealed no neurological deficits. The complaints could not be provoked by briefly turning the head to the left. However, upon prolonged rotation of the head to the left, the patient started to hear a zooming noise. The Dix-Hallpike test showed no abnormalities and the head impulse test to both left and right revealed no corrective saccades or nystagmus. Spurlings’ test provoked local cervical pain without irradiation. Carotid massage of the left artery did not provoke the complaints. The findings at neurological examination did not support the differential diagnosis of a peripheral vestibular syndrome or benign paroxysmal positional vertigo. Cerebral infarction is unlikely in the context of the recurring, transient nature of the symptoms and in the absence of permanent neurological deficits. The patients’ clinical presentation was suggestive for hypoperfusion of the posterior cerebral circulation.
Imaging
A computed tomography (CT) of the cerebrum showed no signs of ischemia or hemorrhage. A CT angiogram (CTA) was performed, which showed no significant intracranial arterial stenosis or occlusion of the common carotid arteries, internal carotid arteries or vertebral arteries. However, it did reveal severe uncovertebral spondylotic spurring of C4-C5 attributing to a left sided transverse foraminal stenosis (Fig. 1). Furthermore, it revealed that the patient had incomplete circle of Willis with a hypoplastic posterior inferior cerebellair artery (PICA) ending right vertebral artery, combined with an ipsilateral fetal posterior communicating artery continuation and a hypoplastic ipsilateral P1 segment. The left posterior communicating artery was hypoplastic resulting in the absence of anterior to posterior collateral supply on the left side. The vascular anatomy is depicted in a 3D reconstruction (Fig. 2) and a schematic overview (Fig. 3). A significant stenosis of the dominant left vertebral artery supplying the basilar artery and posterior cerebral artery on the left was not present in anatomical scanning position. Because clinical presentation combined with CTA outcome were highly suggestive for BHS, it was decided to proceed with a digital subtraction angiography (DSA) with the possibility for dynamic head movement. DSA demonstrated an isolated basilar and left ACP vascular supply from the left vertebral artery following firm contrast injection (Fig. 4). In addition, DSA then did confirm a severe stenosis of the left vertebral artery at the level of C4-C5, occurring only during left-sided rotation of the head (Fig. 5).
Figure 2 3D reconstruction of the computed tomography angiogram of the Circle of Willis shows a hypoplastic posterior inferior cerebellar artery (PICA) ending right vertebral artery, an ipsilateral fetal posterior communicating artery continuation with hypoplastic P1 segment and a hypoplastic left posterior communicating artery (PCOM), resulting in an absence of anterior to posterior collateral supply on the left side
Surgical intervention
Once the diagnosis of BHS was established the patient was offered treatment options including conservative or surgical management. Conservative treatment consisted of preventing head rotation that luxates symptoms and potentially anticoagulation medication for stroke prevention. The proposed and performed neurosurgical was decompression of the left sided vertebral artery at level C4-C5 by resecting the spondylotic spurring and followed by anterior cervical discectomy of C4-C5 and fusion. A 5mm polyethertherketone (PEEK) cage was placed between corpora C4 and C5 and no plate was used. Adequate surgical decompression of the left vertebral artery was confirmed with intra-operative DSA with the head in neutral position and with a 50-degree rotation to the left (Fig. 6). Removal of spondylotic spurring and decompression of the vertebral artery completely resolved the patients’ signs and symptoms.