Carotid artery blood flow during premanipulative testing

BACKGROUND: Cervical manipulation is used millions of times every year. Concern about cerebrovascular accidents (CVAs) is common, but actual cases are rarely reported. Premanipulative tests are presumed to identify patients at risk of CVA. In an earlier study we found no significant changes in the vertebral artery blood flow of patients with a positive premanipulative test with different head positions. Consequently, we questioned whether there is a role for premanipulative testing to identify patients at risk of CVAs. OBJECTIVE: The aim of this study was to examine whether instead, blood flow velocity in the internal carotid arteries changes with head position in patients with a positive premanipulative test, potentially giving contraindication to cervical manipulation. METHODS: In a prospective study private practicing chiropractors from 3 Danish counties referred patients with a positive premanipulative test for an examination of cervical artery blood flow. Premanipulative testing was performed by an experienced chiropractor, and flow velocities were measured in both vertebral and internal carotid arteries by color duplex sonography at a university hospital vascular laboratory. RESULTS: A total of 11 consecutive patients with a positive premanipulative test were referred. Two of these were excluded because we could not reproduce any symptoms at repeat premanipulative testing before the vascular examination. In the remaining 9 patients we found no significant difference with different head positions in peak flow velocity or time-averaged mean flow velocity in the internal carotid arteries. Blood flow did not cease in 1 single patient despite a positive premanipulative test in all. CONCLUSION: It appears that a positive premanipulative test is not associated with a change in peak flow velocity or time-averaged mean flow velocity in either the carotid or the vertebral arteries. If premanipulative testing is used solely for the detection of vascular insufficiency as a potential substrate for CVAs after cervical manipulation, we believe that premanipulative testing is of little clinical value.