Should we abandon positional testing for vertebrobasilar insufficiency?

Abstract

Positional testing for vertebrobasilar insufficiency (VBI) is used by physiotherapists as part of pre-manipulative screening protocols. Recently, the validity of the tests have been questioned because a negative test does not infer safety with cervical manipulative therapy but the reasoning surrounding this opinion may be questioned. While the positional tests were developed to test vertebral artery flow contralateral to the direction of head movement and the subsequent effect on cerebral blood supply, as inferred by symptom reproduction, ultrasound studies have shown that vertebral artery flow is inherently variable. Rather, the tests should be considered as testing for adequacy of collateral flow in particular head positions rather than decreased blood flow in a particular artery, with more attention to characteristics of symptom reproduction. We contend that positional testing for VBI remains valuable for testing adequacy of collateral flow, and also has an important place as part of the differential diagnosis of individuals with dizziness or imbalance. The physiotherapist's ability to differentially diagnose dizziness and recognise the presence or not of VBI is not only critical for prompt medical investigation and management because it is a risk factor for transient ischaemic events and stroke, but has important influences over management decisions regarding cervical musculoskeletal treatment including exercise interventions. Importantly, the positional tests should not be considered as tests of arterial integrity and used to assess the risk of damage to the vertebral or internal carotid artery or presence of cervical arterial dissection. Urgent research is needed before we abandon positional testing prematurely.