Effects of Exercise and an Integrated Neuromuscular Inhibition Technique Program in the Management of Chronic Mechanical Neck Pain: A Randomized Controlled Trial

https://doi.org/10.1016/j.jmpt.2019.03.011Get rights and content

Abstract

Objective

The aim of this study was to evaluate the effect of adding the integrated neuromuscular inhibition technique (INIT) to therapeutic exercise (TE) in individuals with chronic mechanical neck pain (CMNP).

Methods

In this 34-week, assessor-blind randomized controlled trial, 40 participants (men and women) with CMNP with active or latent myofascial trigger points on the neck muscles were divided into 2 groups. The participants followed 4 treatments per week for 10 weeks. The intervention group followed a TE program in combination with the INIT, whereas the control group followed the same program without the INIT. Both protocols were applied by physiotherapists. Pain, disability, pressure pain threshold, active range of motion, and health-related quality of life were evaluated before, during, and after the intervention, whereas patients were followed for 6 months after completion of treatment. Repeated-measures ANOVA was applied.

Results

Both groups showed a significant improvement in all dependent measures after the intervention (P < .05). However, the intervention group showed greater improvement in the visual analog scale and neck disability index score, in the neck muscles pressure pain threshold, in the range of motion, and in the 36-Item Short Form Health Survey score, than the control group. In many of the above variables this improvement was seen from the second week and was maintained for 6 months after the intervention.

Conclusion

The results of this preliminary study suggest that the addition of the INIT to a TE program had a positive effect on pain, functionality, and the quality of life in individuals with CMNP.

Introduction

Neck pain shows a high rate of recurrence and chronicity. Three out of 10 neck pain patients will develop chronic symptoms that last more than 6 months,1,2 whereas 34% will show symptoms for more than 12 months.3 Chronic mechanical neck pain (CMNP) is characterized by a persistence of symptoms for a period longer than 3 months.4 The exact origin and pathophysiological mechanisms of chronic neck pain remain unclear. Many researchers have linked chronic symptoms to changes in neck muscles.5, 6, 7 Individuals with CMNP exhibit muscle weakness and reduced endurance in the neck flexor muscles compared to healthy adults,8 which is highly associated with pain and disability.8,9

Therapeutic exercise (TE) has proven to be beneficial to individuals with CMNP.1,2,9,10, 11, 12, 13 Improvement of neck muscle strength and endurance has been associated with pain reduction and improved functional capacity. Six weeks of TE in people with CMNP resulted in short-term effects by reducing pain and improving neck muscle weakness and isometric strength,14 but these effects do not seem to remain after 6 months. In contrast, Ylinen et al13 reported long-term benefits with pain reduction and disability improvement following a 12-month TE program.

The TE programs of individuals with CMNP often involve resistance and endurance training for neck and shoulder muscles. The combination of both is a more complete approach with better results.4,13,15,16

Many researchers have pointed out the therapeutic value of combining TE with manual therapies.2,17,18 Miller et al16 reported that the combination of exercise and manipulation or mobilization of the cervical and thoracic spine brought better short- and medium-term reduction of pain and disability than the application of each type separately. However, in studies that have implemented a combination of exercise and manipulation in contrast to manipulation only, it is not clear whether the differences identified between the groups are due to the exercise alone or to the particular combination.19 Thus, the appropriate choice of techniques and dosage requires further investigation.18

Many researcher studies associate neck pain with the presence of myofascial trigger points (MTrPs) in the neck muscles.20, 21, 22 MTrP has been defined as a hyperirritable spot within a taut band of skeletal muscle fibers painful on compression.23 It has been shown that in people with chronic neck pain there are almost always more trigger points in more than 1 muscle. Cerezo-Téllez et al20 in a study of 2000 patients with chronic neck pain found that all participants displayed trigger points in the cervical muscles with a higher incidence of trigger points in the upper trapezius. However, although the occurrence rate is so high, few studies in chronic neck pain have used a combination of exercise and MTrPs deactivation techniques.21,24 This portrays an important literature gap in the research field of manual therapy. The presence of MTrPs in individuals experiencing chronic pain is associated with increased intramuscular electromyographic activity of the agonist25 and antagonist26 muscles during synergistic muscle activation and with increased muscle fatigue during isometric muscle contraction.27 At the same time, Ylinen et al28 reported that people with chronic neck pain have decreased values in strength and endurance in all muscle groups of the neck compared with healthy individuals. For this reason, this specific combination of exercise and trigger point deactivation technique presents a research interest.

The integrated neuromuscular inhibition technique (INIT) is a manual MTrPs deactivation technique, which has been described by Chaitow.29,30 It includes the combination of the ischemic compression technique, the strain-counterstrain technique, and the muscle energy technique. Sadaat et al31 reported that 1 session of the INIT is able to reduce pain and pressure pain threshold (PPT) in individuals with CMNP due to MTrPs in the upper trapezius muscle. Nagrale et al32 claimed that the INIT is more effective than the muscle energy technique in improving pain, disability, and range of motion (ROM) in individuals with neck pain, whereas Sibby et al33 suggested that the INIT is equally effective with laser application in upper trapezius MTrPs.

The INIT, based on the phenomenon of reciprocal inhibition and post-isometric relaxation, can resolve muscle spasm in painful areas29,30 and thus could be optimally combined with TE in muscles housing MTrPs. The combination of TE and manipulation, mobilization, or connective tissue massage has been employed recently for treating CMNP.19,34, 35, 36, 37, 38 However, the combination of TE and a MTrPs deactivation technique has not been widely applied. The purpose of this study was to evaluate the effect of adding INIT to a TE program for management of CMNP. The hypothesis of this study was that the combination of INIT and TE yields greater improvement in pain, disability, neck muscle tenderness, neck ROM, and quality of life of patients with CMNP than TE alone. To better monitor treatment effects, several intermediate measurements were performed.

Section snippets

Design

This was an assessor-blind, randomized controlled trial (clinicaltrials.gov number: NCT02802189). Two experienced physiotherapists applied the 2 protocols, the first was responsible for supervising and conducting the exercise program and the second was implementing the INIT and relaxation exercises. It was not possible for care providers or participants to be unaware of group allocation. A masked assessor conducted the measurements.

Participants signed an informed consent and were randomly

Participants

During the recruitment period 62 individuals applied for evaluation. Of these, 8 people refused to participate in the research and 14 did not meet the inclusion criteria. Forty were randomly assigned to the 2 groups. Counseling and education of patients on the benefits of cervical muscle exercise was provided to the participants of both groups at the beginning of the study. According to O'Riordan et al,4 the fear of suffering pain and the lack of knowledge of exercise benefits are strictly

Discussion

The results of this study suggest that both groups experienced a clinically meaningful improvement in all the variables examined during the intervention period. However, the IG showed greater improvement in several variables over CG. This provides support to our hypothesis that the addition of the INIT to TE may be beneficial for treating patients with CMNP.

The VAS score was reduced in both groups during the intervention period. However, this reduction was greater in the IG in all follow-ups (

Conclusion

The results of this preliminary study suggest that the therapeutic combination of TE and the INIT may be more effective than TE alone in the management of CMNP, as reflected by a greater reduction in pain, disability, local tenderness of the muscles, and some indices of health-related quality of life.

Funding Sources and Conflicts of Interest

No funding sources or conflicts of interest were reported for this study.

Contributorship Information

Concept development (provided idea for the research): D.E.L., E.I.S., K.I.C., E.K.

Design (planned the methods to generate the results): D.E.L., E.I.S., K.I.C., I.S.M., E.K.

Supervision (provided oversight, responsible for organization and implementation, writing of the manuscript): D.E.L., E.I.S., K.I.C., E.K.

Data collection/processing (responsible for experiments, patient management, organization, or reporting data): D.E.L., E.I.S., I.S.M.

Analysis/interpretation (responsible for statistical

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