This is now the fourth clinical trial published since 1996 comparing Activator-assisted manipulation to manual thrust manipulation for neck pain. Overall, it is a well designed study. However, the results are inconsistent with the findings from three previous clinical trials which reported that manual-thrust manipulation and Activator-assisted manipulation were equally effective in the treatment of neck pain.
Strengths: All Instrument-assisted manipulations were administered using an Activator IV instrument on a setting of “2” with the manipulative force delivered to the pedicle-lamina junction of the involved segment in an anterior, superior, and slightly medial line of drive. Furthermore, the manipulations were administered by a practitioner with 29 years of clinical experience in instrument manipulation.
Weaknesses: In this trial, the instrument was used only as a biomechanical device, and no Activator Method analytical protocols were used. The choice of which level of the cervical spine to address was at the discretion of the clinician following static palpation. Also, each type of treatment was delivered by a single clinician, and it is possible that part of the treatment response was due to indirect contextual factors related to participant-provider interaction, rather than the direct effect of the treatment alone.
The results are not definitive, and further research investigating the nature of these changes is warranted, but I applaud the efforts of my Australian research colleagues.
The purpose of this study was to compare the effects of 2 different cervical manipulation techniques for mechanical neck pain (MNP).
Participants with MNP of at least 1 month’s duration (n = 65) were randomly allocated to 3 groups: (1) stretching (control), (2) stretching plus manually applied manipulation (MAM), and (3) stretching plus instrument-applied manipulation (IAM). MAM consisted of a single high-velocity, low-amplitude cervical chiropractic manipulation, whereas IAM involved the application of a single cervical manipulation using an (Activator IV) adjusting instrument. Preintervention and postintervention measurements were taken of all outcomes measures. Pain was the primary outcome and was measured using visual analogue scale and pressure pain thresholds. Secondary outcomes included cervical range of motion, hand grip-strength, and wrist blood pressure. Follow-up subjective pain scores were obtained via telephone text message 7 days postintervention.
Subjective pain scores decreased at 7-day follow-up in the MAM group compared with control (P = .015). Cervical rotation bilaterally (ipsilateral: P = .002; contralateral: P = .015) and lateral flexion on the contralateral side to manipulation (P = .001) increased following MAM. Hand grip-strength on the contralateral side to manipulation (P = .013) increased following IAM. No moderate or severe adverse events were reported. Mild adverse events were reported on 6 occasions (control, 4; MAM, 1; IAM, 1).
This study demonstrates that a single cervical manipulation is capable of producing immediate and short-term benefits for MNP. The study also demonstrates that not all manipulative techniques have the same effect and that the differences may be mediated by neurological or biomechanical factors inherent to each technique.
Author information: Gorrell LM, Beath K, Engel RM. Macquarie University, Sydney, NSW, Australia.