• Manual therapy;
• Cervical;
• Risk factors;
• Adverse events

We would like to congratulate Rushton et al. for the study entitled “International Framework for Examination of the Cervical Region for Potential of Cervical Arterial Dysfunction prior to Orthopaedic Manual Therapy Intervention” as published in this journal. We praise the initiative of conducting a clinical reasoning framework for best practice for the examination of the cervical spine region. It is important to aid clinicians in their clinical reasoning process to providence effective and safe manual therapy. As serious conditions such as cervical artery dissection (CAD) or upper cervical instability may mimic musculoskeletal dysfunction in the early stages, these should be recognized in the patient’s history and clinical assessment. We agree with the authors that the manual therapist cannot rely on the results of one test to draw firm conclusions regarding the presence or risk of CAD. The authors developed a clinically reasoned understanding of the patient’s presentation, including a risk benefit analysis. Their study provides important information for clinicians to reconsider before applying manual therapy interventions. However, there are some topics specifically related to the identification of a person at risk for CAD that we would like to debate.

The strength of possible risk factors for neuro-vascular pathology such as CAD is largely unknown (Arnold and Bousser, 2005 and Kerry et al., 2008). It is important here to realize that the limited available data concern risk factors for CAD in general, and not for CAD as a possible consequence of cervical manipulation. In addition, a number of cardiovascular risk factors are associated with atherosclerosis which is an intermediate outcome for CAD while the relationship between atherosclerosis and CAD is not yet clear (Rubinstein et al., 2005 and Kerry et al., 2008). Furthermore, when the association of cardiovascular risk factors (hypertension, smoking status, high cholesterol) with CAD is critically examined, there seems to be a protective effect instead of a risk effect (Thomas et al., 2011). Therefore, the question arises whether we are measuring the right risk factors. The measurement of hypertension as a possible risk factor for CAD (OR = 0.29) does not seem to be useful. The IFOMPT framework correctly states that there is limited diagnostic utility data related to many possible risk factors (Rushton et al., 2013) and that the interpretation must be in context of other findings.

Similarly, premanipulative tests for upper cervical spine instability or vertebrobasilar insufficiency do not seem to be of value in practice due to low diagnostic accuracy and low pretest probability (Hutting et al., 2013a and Hutting et al., 2013b). Especially, the low sensitivity of these tests results in a high rate of patients that are wrongly classified as ‘low-risk patients’ for serious adverse events. It has been demonstrated that the younger people (<45 years) showed an increased risk to develop a CAD after a cervical manipulation, as opposed to older people with multiple risk factors for atherosclerosis (Schievinck, 2001,Rothwell et al., 2001, Rubinstein et al., 2005 and Cassidy et al., 2008).

Moreover, it is advisable to further examine the risk of serious complications after cervical manipulations. This provides insight into the clinical value of the risk factors. However, the consequences for clinical decision-making may still remain small in the context of extreme low pretest probabilities.

Each estimate of the increased risk of CAD should be weighed against the pretest probability of CAD that each person has. The annual incidence of a spontaneous CAD is 2.3–3 per 10.000 people and CAD is more common in relatively healthy young people (Schievinck, 2001,Dziewas et al., 2003 and Debette and Leys, 2009). There is limited evidence that these people have vascular anomaly or genetic predisposition (Dittrich et al., 2007 and Debette and Leys, 2009). An insignificant trauma of the neck or cervical manipulation may then trigger CAD (Debette and Leys, 2009 and Thomas et al., 2011). However, it is also likely that these people would get a spontaneous CAD anyway. Given the low incidence of CAD in this age group, it seems impossible to correctly identify these people at risk during screening prior to cervical manual therapy. This is consistent with the findings of a recent review which showed that 10% of the adverse complications involving CAD could not have been avoided if a more accurate and thorough reasoning process and physical assessment had been used (Puentedura et al., 2012).

We are thankful for the opportunity of discussing this issue and hope to assist the authors of this framework to further improve the safety of cervical manual therapy.

References

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