IMMEDIATE EFFECTS ON NECK PAIN AND ACTIVE RANGE OF MOTION AFTER A SINGLE CERVICAL HIGH-VELOCITY LOW-AMPLITUDE MANIPULATION IN SUBJECTS PRESENTING WITH MECHANICAL NECK PAIN: A RANDOMIZED CONTROLLED TRIAL
 
   

Immediate Effects on Neck Pain and
Active Range of Motion After a Single
Cervical High-velocity Low-amplitude
Manipulation in Subjects Presenting with
Mechanical Neck Pain:
A Randomized Controlled Trial

This section was compiled by Frank M. Painter, D.C.
Send all comments or additions to:
   Frankp@chiro.org
 
   

FROM:   J Manipulative Physiol Ther 2006 (Sep);   29 (7):   511–517 ~ FULL TEXT

Martinez-Segura R, Fernandez-de-las-Penas C, Ruiz-Saez M,
Lopez-Jimenez C, Rodriguez-Blanco C

Escuela de Osteopatia de Madrid,
Madrid, Spain


Single High-Velocity Adjustment May Benefit Neck Pain

Thanks to Chiropractic Research Review for access to these comments!

Commentary:     A recent study performed in Spain has shown an immediate benefit from one adjustment in subjects with mechanical neck pain. The objective of this study was to analyze the immediate effects on neck pain and active cervical range of motion after a single cervical high-velocity, low-amplitude (HVLA) manipulation or a control mobilization procedure. The possible correlation between neck pain and neck mobility also was investigated.

A group of 70 patients with neck pain (25 males and 45 females, ages 20-55 years) participated in this study. The lateral gliding test was used to establish an intervertebral joint dysfunction at the C3 through C4 or C4 through C5 levels. The subjects were randomly divided into either an experimental group, which received an HVLA thrust, or a control group, which received manual mobilization. The outcome measures were active cervical range of motion and neck pain at rest, assessed before the treatment and five minutes after it. Intragroup and intergroup comparisons were made with parametric tests.

The HVLA group showed a significant improvement in neck pain at rest and mobility after application of the manipulation. The control group also showed a significant improvement in neck pain at rest, flexion, extension, and both lateral flexions, but not in rotation. Pre-post effect sizes were large for all the outcomes in the experimental group, but were small to medium in the control mobilization group. The intergroup comparison showed that the experimental group obtained a greater improvement than the control group in all the outcome measures. Decreased neck pain and increased range of motion were negatively associated for all cervical motions - the greater the increase in neck mobility, the less the pain at rest.

Results suggest that a single cervical HVLA manipulation is more effective in reducing neck pain at rest, and in increasing active cervical range of motion, than a control mobilization procedure in subjects suffering from mechanical neck pain.


PURPOSE:   The objective of this study is to analyze the immediate effects on neck pain and active cervical range of motion after a single cervical high-velocity low-amplitude (HVLA) manipulation or a control mobilization procedure in mechanical neck pain subjects. In addition, we assessed the possible correlation between neck pain and neck mobility.

METHODS:   Seventy patients with mechanical neck pain (25 males and 45 females, aged 20-55 years) participated in this study. The lateral gliding test was used to establish the presence of an intervertebral joint dysfunction at the C3 through C4 or C4 through C5 levels. Subjects were divided randomly into either an experimental group, which received an HVLA thrust, or a control group, which received a manual mobilization procedure. The outcome measures were active cervical range of motion and neck pain at rest assessed pretreatment and 5 minutes posttreatment by an assessor blinded to the treatment allocation of the patient. Intragroup and intergroup comparisons were made with parametric tests. Within-group effect sizes were calculated using Cohen's d coefficient.

RESULTS:   Within-group changes showed a significant improvement in neck pain at rest and mobility after application of the manipulation (P < .001). The control group also showed a significant improvement in neck pain at rest (P < .01), flexion (P < .01), extension (P < .05), and both lateral flexions (P < .01), but not in rotation. Pre-post effect sizes were large for all the outcomes in the experimental group (d > 1), but were small to medium in the control mobilization group (0.2 < d < 0.6). The intergroup comparison showed that the experimental group obtained a greater improvement than the control group in all the outcome measures (P < .001). Decreased neck pain and increased range of motion were negatively associated for all cervical motions: the greater the increase in neck mobility, the less the pain at rest.

CONCLUSION:   Our results suggest that a single cervical HVLA manipulation was more effective in reducing neck pain at rest and in increasing active cervical range of motion than a control mobilization procedure in subjects suffering from mechanical neck pain.


From the Full-Text Article:

Introduction

Mechanical neck pain affects 45% to 54% of the general population at some time during their lives [1] and can result in severe pain and disability. [2] The exact pathology of mechanical neck pain is not clearly understood, but it is purported to be related to various anatomic structures, including ligaments, muscles, zygapophysial joints, uncovertebral joints, intervertebral disks, or neural tissues. Bogduk and Aprill [3] hypothesized that one of the most common causes of neck pain is related to mechanical dysfunction of the cervical spine. Intervertebral joint dysfunctions are defined as a reduction of mobility of a cervical segment [4] and, if identified on clinical examination, is often the focus of treatment of mobilization/manipulation. [5] It has been found that spinal manipulative therapy is one of the most used therapies in the management of mechanical neck disorders. [5, 6]

The aim of mechanical neck pain treatment is to reduce the pain and restore normal function of the cervical spine. Previous studies have demonstrated that spinal manipulative therapy is effective in reducing pressure pain threshold [7] and increasing cervical range of motion [8-10] in patients presenting with mechanical neck pain. Another study has reported that no lasting changes in passive cervical range of motion occur after spinal manipulation. [11] Cassidy et al [8] compared the immediate effects of spinal manipulative therapy, with muscle energy techniques as the mobilization procedure, on pain and range of motion in the cervical spine. These authors found that both treatments were equally effective in improving cervical range of motion, but spinal manipulation was more effective than muscle energy techniques in decreasing pain. [9] Pikula [12] also analyzed the immediate effects of spinal manipulative therapy, compared with detuned ultrasound therapy, on neck pain and cervical range of motion. This study found greater decreased neck pain and increased cervical range of motion in those patients who received spinal manipulation compared with those receiving placebo therapy (detuned ultrasound therapy). [12]

Although Cassidy et al [8] and Pikula [12] analyzed the immediate effects on pain and range of motion of spinal manipulative therapy in the cervical spine, these studies did not include a control group receiving a manual mobilization procedure. The aim of this randomized controlled study was to analyze the immediate effects on neck pain and active cervical range of motion after a single cervical high-velocity low-amplitude (HVLA) manipulation or a control mobilization procedure in patients suffering from mechanical neck pain. In addition, we assessed the possible correlation between the decrease in neck pain and the increase in neck mobility on each cervical motion.



Discussion

The present study demonstrated that a single cervical HVLA manipulation was more effective in reducing neck pain at rest and in increasing active cervical range of motion than a control mobilization procedure in subjects suffering from mechanical neck pain. Furthermore, the effect size in the manipulative group was large, suggesting a strong clinical effect, whereas the effect size of the control group was small. The present study also demonstrated that decreased neck pain and increased range of motion were negatively associated. Cassidy et al [8] also found a relationship between a decrease in neck pain and an increase in cervical range of motion, but only significant for both rotation motions. Because of the small sample size of the Cassidy et al study, there was a greater probability of creating a type II error.

Our results are in agreement with previous studies. Cassidy et al [8] reported that spinal manipulation in the cervical spine was equally effective in improving cervical range of motion, but more effective in reducing neck pain, than a muscle energy technique. Pikula [12] also found greater decreased neck pain and increased cervical range of motion with a cervical manipulation than with detuned ultrasound therapy. Vernon et a [17] reported that cervical manipulation produced significantly higher increases in pressure pain threshold of tender points surrounding a cervical dysfunction in subjects with mechanical neck pain. Fernández-de-las-Peñas et al [24] have recently demonstrated that a supine cervical rotation manipulation resulted in increased intersegmental motion at the dysfunctional side of a cervical vertebra as measured with plain film radiographs during contralateral cervical side flexion. Previous and current findings suggest that spinal manipulative therapy is more effective in reducing pressure pain threshold and increasing cervical range of motion than control mobilization procedure, muscle energy techniques, [9] or detuned ultrasound therapy. [12]

It has been purported that intervertebral joint dysfunctions are characterized by a reduction of mobility of a spinal segment, and that spinal manipulation can potentially affect the mobility of the joint, resulting in alterations of the kinematic behavior of the spine. [4] If treatment is precise, the spinal manipulative procedure should affect the mobility of the hypomobile joint and lead to an increased range of motion at that particular segment. [24] However, Clements et al [25] found that HVLA manipulation of the atlantoaxial joint produced a significant immediate amelioration of passive atlantoaxial rotation asymmetry regardless of whether the HVLA technique was applied unilaterally, either toward or away the restricted rotation, or bilaterally. Moreover, we also found that the increase in cervical range of motion after the manipulative procedure did not depend on the side of the manipulation. Therefore, it could be that HVLA thrust has inherent qualities that can alter the cervical biomechanics, independently of the side and direction of the thrust. It is possible that experienced symptomatic improvement after HVLA thrust also influences the range of motion improvement. It that way, it is possible that the effects of pain modulation rather than direct range of motion effects can led to the changes in active range of motion.

The neurophysiologic mechanisms by which spinal manipulative therapy is effective in reducing pain are not completely understood. One possible mechanism can be that the mechanical stimulation of joint capsule proprioceptors and muscle spindles, caused by the spinal manipulation, may induce a reflex inhibition of pain, reflex muscle relaxation, and improve mobility. [26, 27] Pickar [28] demonstrated that spinal manipulation modifies the discharge of groups I and II (proprioceptive) afferent. Another mechanism might be that the afferent bombardment from joint and myofascial receptors provoked by the manipulative procedure can produce presynaptic inhibition of segmental pain pathways and possibly activation of the endogenous opiate system. [29, 30] After an extensive review of neurophysiologic effects of spinal manipulative therapy, Pickar [31] concluded that more than 1 mechanism likely explains the effects of spinal manipulation. However, we cannot completely exclude a placebo effect by pure fact to put the therapists' hand on the symptomatic area.

Our study has several limitations. First, we only examined the short-term effects of spinal manipulative therapy directed at the cervical spine. The fact that statistically significant changes occurred after spinal manipulation provides impetus for future research in this area. Therefore, further studies are needed to examine long-term effects of cervical manipulation. Moreover, Cleland et al [32] have recently demonstrated that thoracic manipulation was more effective in reducing neck pain than a sham manual procedure. Because thoracic manipulation was also effective in reducing neck pain, it is plausible that spinal manipulative therapy directed at the thoracic spine also provokes an increase in cervical range of motion. That hypothesis needs to be tested in futures studies. Second, we cannot say that our subjects were truly blinded because patients could know that they had been allocated to receive high velocity-low amplitude thrust (joint cavitation) or control mobilization procedure (nontissue tension). The third limitation was the sample size. To definitely establish a cause-and-effect relationship between spinal manipulative therapy and decreased neck pain and increased range of motion, our findings must be confirmed in a large number of subjects.



Conclusion

A single cervical high velocity-low amplitude manipulation was more effective in reducing neck pain at rest and in increasing active cervical range of motion than a control mobilization procedure in subjects suffering from mechanical neck pain. Effect sizes in the manipulative group were large, suggesting a strong clinical effect, whereas the effect size of the mobilization group was small. Decreased neck pain and increased range of motion were negatively associated. More than 1 mechanism likely explains the effects of spinal manipulation.


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