Effects of Low Versus High Frequency Percutaneous Electrical Nerve Stimulation on Chronic Neck Pain Patients.

Study Overview
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Brief Summary
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Comparison between high and low frequency percutaneous electrical nerve stimulation as treatment of myofascial chronic neck pain. The main hypothesis is that low frequency treatment will have more hypoalgesic effects than high frequency, and low frequency effects will last longer.

Official Title
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Comparison and Effects of Low and High Frequency Percutaneous Electrical Nerve Stimulation on Myofascial Chronic Neck Pain Patients.

Conditions
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Neck Pain, Chronic Pain, Myofascial Pain Syndrome

Intervention / Treatment
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* Procedure: Low frequency
* Procedure: High frequency


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Neck pain of more than 6 months of evolution. Pain level of more than 30 millimeter on the VAS scale. Active myofascial frigger points on upper trapezius muscle. Exclusion Criteria: Upper limb radiculopathy. Recent whiplash. Cervicogenic dizziness. Migraine. Previous cervical surgery.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Double blind randomized control trial.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low frequency<br>Percutaneous electrical nerve stimulation with frequency of 2 Hz and 120 microseconds of pulse width will be applied. | Procedure: Low frequency<br>* A dry needling on trapezius muscle is performed, until two local twitch responses are obtained. The needle is kept inside the trigger point, as it will be the negative electrode, and an adhesive electrode will be added as the positive one. After that, a low frequency TENS is applied, at 2 Hz frequency and 120 microseconds of pulse width.<br>* Other names: Low frequency group;|
| Active Comparator: High frequency<br>Percutaneous electrical nerve stimulation with frequency of 120 Hz and 200 microseconds of pulse width will be applied. | Procedure: High frequency<br>* A dry needling on trapezius muscle is performed, until two local twitch responses are obtained. The needle is kept inside the trigger point, as it will be the negative electrode, and an adhesive electrode will be added as the positive one. After that, a high frequency TENS is applied, at 12o Hz frequency and 200 microseconds of pulse width.<br>* Other names: High frequency group;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain | Subjective feeling expressed by subjects in the area of discomfort. It will be measured by a Visual Analogue Scale, meaning a score of 0 points/centimiters no pain and a score of 10 points/centimiters unbearable pain. | Changes on pain will be assessed during one month follow up. Baseline will be measured on the first day and one month later pain score will be reassessed. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pressure pain threshold | Minimal amount of pressure that induces pain. An algometer will be used to measure pressure pain threshold. Units will be kilograms per square centimeter. The higher the score is, the less sensitive the area will be. | Changes on pain will be assessed during one month follow up. Baseline will be measured on the first day and one month later pain score will be reassessed. | 
| Neck disability index. | Ten items questionnaire designed to asses the level of pain and self-assessment of cervical disability. The NDI (Spanish version) is composed of 10 questions related to daily functional activities. NDI presents an acceptable reliability with an intraclass correlation coeffcient (ICC) ranging from 0.50 to 0.98. It has been proposed that the clinically important difference required for NDI is seven points. | Pre treatment at the beginning of the study and one month later, on the last of the follow up period. | 
| kinesiofobia | Eleven items questionnaire designed to asses pain-related fear. TSK-11, Spanish version. | Pre treatment at the beginning of the study and one month later, on the last of the follow up period. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Percutaneous electrical nerve stimulation, Myofascial trigger point