Purpose/Hypothesis: To compare the blood pressure (BP) and heart rate (HR) response of healthy volunteers to posterior glide (AP) of the cervical spine (CS) versus placebo (P). Many manual therapists often employ CS AP for various cervical-shoulder painful conditions. However, there is a paucity of literature describing the procedure and its safety profile. In particular, how it should be performed to avoid doing a carotid sinus massage (CSM) causing vasodepression.

Number of Subjects: Fifty-four (40 females) healthy subjects (mean SD age, 24.5  1.9 years) with no history of syncope, no cardiovascular disease, and no cervical-shoulder pain were randomly assigned to 1 of 2 groups.

Materials/Methods: Group 1 received P when light touch was applied to right C6. Group 2 received AP to the right C6. BP and HR were measured with an OMRON automatic monitor in the following order (time points): (1) 5 minutes and (2) 7 minutes after resting supine, (3) during the first set, (4) during the fifth set of P or AP, and (5) 2 minutes after the fifth set was applied (recovery period). Blinded to the data collected, the primary author performed P or AP on all volunteers. Testing would immediately stop if the systolic blood pressure (SBP) dropped greater than or equal to 50 mmHg below the baseline, or there was an absence of pulse for 3 seconds or longer. ANOVA and paired-difference statistics were applied to determine if there was any SBP drop within each group, and between both groups in all time points. To determine the worst-case scenarios, ANOVA and paired difference were further performed on each group (P or AP) between higher (of time points 1 or 2) baseline SBP to lower (of time points 3 or 4) P (or AP) SBP, and between higher (of time points 1 or 2) baseline SBP to P (or AP) recovery SBP (time point 5).

Results: There was no statistical difference between both groups based on measurements of age, weight, height, SBP (average of time points 1 and 2) for the AP group (108.9  11.7 mmHg) and P group (110.3  12.6mmHg, P>.5), diastolic BP, and HR in all time points, and for each group in all time points except paired difference of: (a) group 1 higher baseline SBP minus lower P SBP (–4.1  3.4 mmHg, P<.01), (b) group 2 higher baseline SBP minus lower AP SBP (–3.1  4.4 mmHg, P<.01), (c) group 1 higher baseline SBP minus P recovery SBP (–4.0  3.8 mmHg, P<.01), and (d) group 2 higher baseline SBP minus AP recovery SBP (–3.3  4.0mmHg, P<.01). No absence of pulses was noted in all subjects at all times during testing periods. Furthermore, none reported any adverse effects within 24 hours of the testing.

Conclusion: The changes in SBP and HR when performing posterior glide (AP) of the cervical spine were statistically not different from those that received placebo (P). The average drop in SBP was –3.1 mmHg, and none had an absence of pulse lasting 3 seconds or longer, thereby indicating its broad safety profile.

Clinical Relevance: The results from this study would therefore justify further study of using this new technique in young adult patients who report neck-shoulder problems.