Immediate effects of concurrent application of transcutaneous electrical nerve stimulation (TENS) and Ultrasound phonophoresis on active trigger point tenderness

Combination Therapy is the simultaneous application of electrotherapy and ultrasound (US) at the same time, used as a single modality. One the other hand phonophoresis is the use of ultrasound to enhance the delivery of topically applied drugs. Phonophoresis has been used in an effort to enhance the absorption of topically applied analgesics and anti-inflammatory agents through the therapeutic application of ultrasound. This study will be conducted at a private clinic located at Heliopolis, Egypt; to compare between the immediate effects of combined therapy phonophoresis, phonophoresis only and US on pressure pain threshold (PPT) and active cervical lateral flexion range of motion (ROM) on upper fibers of trapezius trigger point. To ensure fidelity we explained the entire procedure to the patient; with its aims, and potential unpleasant sensation experience from TENS application and informed him that he has the right to withdraw at anytime during the study duration. 6 free sessions after the completion of the study will be offered to all participants to improve fidelity. Randomized controlled pre-post experimental design will be used. One hundred patients from both genders will participate in the study after signing institutionally approved consent form prior to data collection. Subjects will be randomly assigned into; Group A: 25 subjects will receive combined therapy phonophoresis and passive stretch to the upper trapezius trigger point; once for 10 minutes duration. Group B: 25 subjects will receive phonophoresis and passive stretch to the upper trapezius trigger point; once for 10 minutes duration. Group C: 25 subjects will receive US and passive stretch to the upper trapezius trigger point; once for 10 minutes duration. Group D: control group; 25 subjects will receive sham US and passive stretch to the upper trapezius trigger point; once for 10 minutes duration. A blinded physical therapist with more than 7 years experience will locate, identify and assess tenderness of myofascial trigger points (MTrPs) and active cervical lateral flexion range of motion for all subjects prior to the procedure. Outcome measure will include pressure pain threshold obtained via a digital electronic algometer, as well as active side bending using a smart phone mobile application (Audette et al., 2010 and Tousignant et al., 2006) Data will be collected prior to the application of techniques used as baseline measure and after the application of treatment procedure post-treatment measure. Clinical identification of active-MTrPs will be based on Travel and Simon (1999) essential criteria, where the upper trapezius will placed in a stretched and relaxed position to easily locate MTrPs. Flat or pincer palpation will be used to locate active-MTrPs. Essential criteria for active-MTrPs will include; 1- Palpable taut band: palpation for the taut band, which includes a tender nodule. 2- Exquisite spot tenderness of a nodule: Palpating through a taut band, there was a tender nodular area. Digital compression of the nodule may have elicited a referred pain pattern (RPP). 3- Patient pain recognition: Digital compression reproduced pain. Patients usually identify that it is “their usual pain”. Electing the patient’s pain recognition is a strong essential criterion and can discriminate an active MTrP from a latent one. 4- Painful range of motion at the end of range. He will then mark an "X" on the active-MTrPs found, that are; MTrP1: this central MTrP is found in the mid portion of the anterior border of the upper trapezius and involves the most vertical fibers that attach anteriorly to the clavicle. MTrP2: lies caudal and slightly lateral to MTrP1 which is located in the middle of the more nearly-horizontal fibers of the upper trapezius. A second physical therapist with more than 5 years experience will carry out the treatment procedure and register attendance at sessions. a) Combination therapy device Features of the device: Intelect Advanced color series two channel electrotherapy and combination therapy system will be used in this study; with model number 2752CC (Chattanooga DJO France SAS industries; made in Mexico). It has afFull-color, LCD screen that displays in sharp, vivid detail with main power input of 120-240 VAC- 1.0 A, 50-60 Hz and 175 VA and output of 12 V, 8.3 A Its assembled with more than 34 medium and low frequency electrical currents Ultrasound technical specification includes; a frequency of 1 MHz, +/- 5% and 3.3 Mhz, +/-5%; duty cycles of 10%, 20%, 50% and continuous; a pulse repetition rate of 16, 48 or 100 Hz; a pulse duration of 1 mSec, +/- 20%; 2 mSec, +/- 20%; 5 mSec, +/-20%. Its Output Power includes a 5 cm2 crystal with an effective radiating area of 4.0 cm2, +/- 1.0. Its output accuracy is set at +/- 20% above 10% of maximum. Parameters used; 1- For Combined therapy phonophoresis group: The ultrasound parameters will consist of 1 MHz continuous US set at an intensity of 1.5 W/cm2 and 100Hz repetition rate. Diclofenac sodium 10mg gel will be used instead of coupling US gel used for transmission. The electrical current parameters will include Conventional Transcutaneous electrical nerve stimulation (TENS) that will be set at an asymmetric biphasic waveform; with a phase duration 120 microseconds; cycle time continuous and frequency 150-250 Hz (Weng et al., 2005). Intensity will be increased until the patient feels a strong unpleasant but comfortable sensation. If adaptation occurs the intensity will be raised accordingly. 2- For Phonophoresis group: The ultrasound parameters will consist of 1 MHz continuous US set at an intensity of 1.5 W/cm2 and 100Hz repetition rate. Diclofenac sodium 10mg gel will be used instead of coupling US gel used for transmission. 3- For US group: The ultrasound parameters will consist of 1 MHz continuous US set at an intensity of 1.5 W/cm2 and 100Hz repetition rate. Coupling US gel will be used for transmission. Another certified physical therapist with 5 years experience will carry out treatment techniques. Combination therapy Phonophoresis application: The subject will be comfortably seated and the muscle will be placed in a slightly stretched position to take up the slack; making it easier to find MTrPs. The dispersive negative electrode of channel two will be placed distal to the active MTrPs; on the deltoid muscle (Loharjun, 2013), while the ultrasound head will act as the positive electrode. After adjusting both electrical current and ultrasound parameters, the intensity will be raised up until the sensory threshold. Diclofenac sodium 10mg gel will be used instead of coupling US gel used for transmission, then circular stroking of ultrasound head over active MTrP1 or 2 of upper fibers of trapezius muscle will be applied throughout the 10 minutes of treatment period. each MTrP will be treated separately for 10 minutes Same procedure will be applied to Phonophoresis Group and US, but with the parameters stated above. For the Control group that will receive sham US; the same therapeutic ultrasound machine will be applied as experimental groups but the electrical current during treatment period will be turned-off (Loharjun, 2013) Passive stretch will be applied directly after the interventions for all groups. With the patient in a seated position; we will stabilize the patient's scapula with one hand pressing laterally and downward on the scapula, while the other hand placed on the side of the head applying the stretching force towards flexion, side bending to the opposite side and rotation to the same side. The stretched position will be sustained for 30 seconds, then a relaxation period of 30 seconds and repeated 3-5 times. Release is augmented by having the patient coordinate downward eye motion and slow exhalation with relaxation. (Simons et al., 1999)