Vascular flow limitations affecting the cervico-cranial region: Understanding ischaemia

Abstract

Background: Blood flow and brain ischaemia have been of interest to physical therapists for decades. Despite much debate, and multiple publications around risk assessment of the cervical spine, more work is required to achieve consensus on this vital, complex topic. In 2020, the International Federation of Orthopaedic Manipulative Physical Therapists (IFOMPT) Cervical Framework adopted the dubious terminology 'vascular pathologies of the neck', which is misleading, on the premise that 1) not all flow limitations leading to ischaemia, are associated with observable blood vessel pathology and 2) not all blood flow limitations leading to ischaemia, are in the anatomical region of the 'neck'.

Objective: This paper draws upon the full body of haemodynamic knowledge and science, to describe the variety of arterial flow limitations affecting the cervico-cranial region.

Discussion: It is the authors' contention that to apply clinical reasoning and appropriate risk assessment of the cervical spine, there is a requirement for clinicians to have a clear understanding of anatomy/anatomical relations, the haemodynamic science of vascular flow limitation, and related pathologies. This paper describes the wide range of presentations and haemodynamic mechanisms that clinicians may encounter in practice. In cases with a high index suspicion of vascular involvement or an adverse response to assessment/intervention, appropriate referral should be made for further investigations, using consistent terminology. The term 'vascular flow limitation' is proposed when considering the range of mechanisms at play. This fits the terminology used (in vascular literature) at other anatomical sites and is understood by medical colleagues.

Keywords: Cervico-cranial; Ischaemia; Neck; Physical therapy; Risk assessment; Vascular.

Fig. 1

Cervico-cranial vasculature, including the circle of Willis.Reprinted and adapted with permission from 123RF ©123RF.com.

Fig. 2

Pathology of subclavian steal syndrome. Reprinted from Konda et al.,copyright 2015, with permission from Elsevier.

Fig. 3

Angiogram of the right vertebral artery. Fig. 3a shows the normal appearance of the right vertebral artery during the angiogram performed in neutral head position. Fig. 3b shows evidence of flow disruption (level of C7) during the angiogram performed in right head rotation. Reprinted from Lee et al.,copyright 2011, with permission from Elsevier.

Fig. 4

Various Manifestations of Intracranial Dissections. A. During initiation of the arterial dissection blood dissects into the subintimal space to create a false lumen to create an intramural haematoma. B. If there is an exit site for the dissection then a true and false lumen appear. There can be emboli from the intramural haematoma in the false lumen that result in embolic stroke. C. If the intramural haematoma involves the origin of perforator vessels, perforator occlusion can occur. D. If the intramural haematoma lacks an exit site, it can build up to eventually cause occlusion of the parent artery. E. If the haematoma breaks through the adventitia then pseudoaneurysm formation can occur. Reproduced with authorization from Bond et al.,copyright © Elsevier Masson SAS.

Fig. 5

The lowest four cranial nerves are shown emerging from the jugular and hypoglossal foramina, where they join the sympathetic plexus within the carotid sheath. Here, these structures are vulnerable to the compressive effects of the dilatation of the artery resulting from a carotid artery dissection. Reprinted from Fitzerald et al.,copyright 2007, with permission from Elsevier.

Fig. 6

A: Normal length styloid process and associated vascular and neural structures. Fig. 7B: Elongated styloid process travelling just proximal to the carotid bifurcation as seen in patients with Eagle syndrome. ICA = internal carotid artery. ECA = external carotid artery. IJV = internal jugular vein. CN X = cranial nerve 10 – vagus nerve. Image by Jill Gregory, reprinted with permission from ©Mount Sinai Health System.

Fig. 7

Arterial supply to the retina. Reprinted from Harris et al.,copyright 2019, with permission from Springer Nature Customer Service Centre GmbH.