VBI

I hope clinic is going well for everyone. I wanted to bring up the topic of vertebral basilar insufficiency. At Curtin Clinic, patients with neck pain are routinely asked for whether they have symptoms of vertebral basilar insufficiency. The checklist of symptoms include a history of any of the following: dizziness, drop attacks, dysarthria, dysphagia, and double vision (the five “D’s”). Other commonly asked symptoms are the presence of unilateral tongue and face paresthesia, ataxia, hemianaesthesia and hemiplegia. I wonder as to the purpose of these screening questions.

Depending on your reference, there is a 1/100000 to 1/1000000 chance of suffering a stroke from cervical manipulations. The stroke usually occurs in the vertebral artery or the PICA, causing a lateral medullary syndrome. Theoretically, spasm of the vertebral artery can occur, causing a possible embolism. This usually occurs at the C1-2 area, where the vertebral artery takes a tortuous course before entering the foramen magnum. Manipulations to this area of the spine can physically stretch the artery and set off arterial spasm, in particular those with congenitally short vertebral arteries. My understanding is that positive responses to these screening questions would contraindicate the use of cervical manipulations. If the VBI screening questions are meant to exclude patients from receiving cervical manipulations, why ask about possible symptoms that can occur secondary to cervical manipulations before they occur?

The logical answer is that the VBI screening questions are not simply meant to identify those who are at higher risk of suffering a stroke from cervical manipulations, but have implications on assessment and treatment techniques. If that is so, what kind of patient besides those who had suffered a vertebrobasilar stroke has symptoms of drop attacks, dysarthria, dysphagia, and double vision? Can a person turn their head to EROM and cause immediate VBI symptoms such as dysarthria? (If they did, would they be able to tell you about it? - THAT IS A JOKE) Dizziness doesn’t really count, since many conditions can result in dizziness, like middle ear infections and Meniere’s disease.

I am sure there are good reasons behind asking these screening questions. Petty (one of our many musculoskeletal texts) referenced Bogduk (1994) for including the VBI questions as a part of a subjective. Bogduk is a big time researcher from the Uni of Newcastle and his work is usually taken as gospel. Nonetheless, Petty did not give the rationale behind using the screening questions. I have not found an answer for it, (actually I haven’t looked too hard). I wanted to bounce the question around this forum to get some ideas before I get some answers (starting with my clinical supervisor, then the article by Bogduk). Thanks.