Changes in Cerebellar Blood Flow After Manipulation of the Cervical Spine Using Technetium Tc 99m Ethyl Cysteinate Dimer

Cagnie et al1 suggested that there may be a relationship between cervical manipulation and hypoperfusion in the anterior lobe of the cerebellum. However, we consider that other methodologically uncontrolled factors were more likely to have contributed to their findings. Moreover, the authors did not provide enough evidence to single out manipulation and its influence on the vertebral artery (VA), concluding that it may have contributed to the reported cerebellar hypoperfusion.

It does not seem plausible that unilateral hypoperfusion would occur in the anterior lobe of the cerebellum as a result of unilateral VA compromise while sparing the more proximal vessels. If hypoperfusion were to occur as a consequence of unilateral VA compromise, one would expect involvement of the posterior inferior cerebellar artery, which was not reported. Furthermore, if unilateral VA blood flow compromise were to occur, blood from both VAs would be combined while passing through the basilar artery, before reaching the left superior cerebellar artery (SCA). Accordingly, any decreased blood flow emanating from the VAs would be much more likely to affect both SCAs. The authors mentioned this scenario as a limitation of their study but went on to conclude,1 “…that cerebellar hypoperfusion may occur after the type of cervical manipulation that was used in this study.”

The authors cited two articles that were purported to report infarction in the region supplied by the SCA that was associated with stenosis of the ipsilateral VA.2, 3 After checking these sources, however, the articles that were referred to did not support a contributing relationship that would be applicable to their findings. The article by Bonkowsky et al2 reported a case of infarction in the region supplied by the SCA and concomitant VA stenosis at the C2 level, but they went on to state, “…a thromboembolism of the left SCA is most likely to explain the infarct in our case.” The other article discussed the blood supply of the cerebellum and presented clinical characteristics on 10 patients who experienced cerebellar infarcts. It also mentioned the possibility of artery-to-artery embolization but presented nothing that would support a contributory relationship between stenosis of the VA and unilateral infarction of the SCA territory.

In summary, the authors' statement that cerebellar hypoperfusion may occur after the type of cervical manipulation that was used in their study is not supported by their data. Cerebellar hypoperfusion may have occurred after several other aspects of the procedure that was used (ie, head positioning or head movements that were associated with the manipulative procedure) or equipment malfunction that may have systematically introduced an artifact simulating hypoperfusion. Inclusion of a nonthrust control group or having some of the participants receive manipulation on the opposite side could have answered some of these questions. As it stands, compromise of the VA blood flow should not have been singled out as the most likely contributing factor of hypoperfusion in the anterior lobe of the cerebellum as was presented.