This study evaluates the effects of corticosteroid injections over time, as well as the additional effect provided by subsequent transcranial direct current stimulation (tDCS) of the motor cortex on patients with rotator cuff tendinopathy of the shoulder. All patients will receive a subacromial corticosteroid injection. Two weeks later, a third will receive a treatment of tDCS, a third will receive a placebo a-tDCS treatment, and the last third will not receive any additional treatment.
Corticosteroid injections (CSI) are often used by physicians in the treatment of rotator cuff tendinopathy, a painful chronic degeneration of the tendons in the shoulder. However, the effect of CSI in comparison with placebo is disputed in the scientific literature, with most studies only showing mild short-term effect (less than six weeks) on pain compared to placebo injections. Transcranial direct current stimulation (tDCS) is a non-invasive technique allowing to stimulate areas of the brain in order to change the excitability of the neurons. When the negative electrode is applied on the motor cortex of the brain, it increases the excitability of the neurons in that area, which in turns inhibits the activity of the thalamus, an area of the brain linked with the perception of pain. Some studies have shown that tDCS can improve chronic pain of different origins, such as lower back pain, fibromyalgia, stroke, osteoarthritis, and post-operative pain. We tested whether applying tDCS following a CSI would have more effect on patient's pain, function, and activity, than CSI alone.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
38
The tDCS anode was applied on the primary motor cortex area responsible for the control of the rotator cuff, as determined using transcranial magnetic stimulation and surface electromyography. The cathode was applied on the contralateral forehead, just above the eyebrow. The electrodes were soaked in saline solution to improve conductivity and the montage was secured with rubber bands and adhesive tape. The tDCS device (Soterix Medical 1x1 tDCS device) was then gradually turned to an intensity of 2mA. This stimulation was continued for a total of 20 minutes, after which it was gradually stopped.
Western Ontario Rotator Cuff index (WORC)
The WORC is a health related quality of life questionnaire developed specifically to assess outcome in patients with rotator cuff disease. It includes 21 questions in the form of visual analog scales (VAS) covering five domains: physical symptoms, sports and recreation, work, quality of life, and emotional status. The final score can be reported over 100 points, with a higher score represents better function.
Time frame: Two weeks following tDCS (four weeks after CSI)
Western Ontario Rotator Cuff index (WORC)
The WORC is a health related quality of life questionnaire developed specifically to assess outcome in patients with rotator cuff disease. It includes 21 questions in the form of visual analog scales (VAS) covering five domains: physical symptoms, sports and recreation, work, quality of life, and emotional status. The final score can be reported over 100 points, with a higher score represents better function.
Time frame: One week before the CSI, day of the CSI (just prior to the injection), two-weeks after CSI (just prior to tDCS),eight weeks after CSI (six weeks after tDCS)
Short version of the Disability of the Arm, Shoulder and Hand questionnaire (QuickDASH)
The QuickDASH is a health related quality of life questionnaire developed for pathologies affecting the arm, shoulder and hand. It consists of 11 questions in the form of Likert scales. The score can be reported on a scale of 0 to 100, with higher score representing worse outcome.
Time frame: One week before the CSI, day of the CSI (just prior to the injection), two-weeks after CSI (just prior to tDCS), four weeks after CSI, eight weeks after CSI
Pain visual analog scale (pain VAS)
The participant will be asked to rank their pain for the last 24h on a VAS, with anchors being "no pain" on the left end, and "Extreme pain" on the right end.
Time frame: Filled every day, but it will be averaged for every week, starting one week before the CSI and ending four weeks after, with an additional week eight weeks following CSI.
Shoulder Range of Motion (ROM)
Shoulder ROM will be measured using a goniometer and reported in degrees in six different planes: abduction, flexion, scapular elevation (scaption), external rotation with the arm at the side, external rotation with the arm abducted 90 degrees and internal rotation with the arm abducted 90 degree. Additionally, internal rotation will also be measured visually with the maximal spinal level reached by the thumb with the hand at the back.
Time frame: One week before the CSI, day of the CSI (just prior to the injection), two-weeks after CSI (just prior to tDCS), four weeks after CSI
Shoulder strength
Using a hand-held dynamometer, shoulder strength will be measured in three planes: scapular plane with the thumb pointed down (Jobe test, or empty can test), external rotation with the arm adducted, internal rotation with the arm adducted
Time frame: One week before the CSI, day of the CSI (just prior to the injection), two-weeks after CSI (just prior to tDCS), four weeks after CSI
Shoulder activity VAS
The participants will be asked to rank their estimated affected shoulder use for the last 24h using a VAS, with the left anchor being "Not at all" and the right anchor being "All the time".
Time frame: Filled every day, but it will be averaged for every week, starting one week before the CSI and ending four weeks after, with an additional week eight weeks following CSI.
Arm usage measured by actimetry
An accelerometer developed at our institution (WIMU-GPS) will be worn at the wrist during the day for a total of five weeks. It will record acceleration, angular velocity, and magnetic field interactions in order to estimate upper extremity usage. At the time of initial ethical approval, the exact algorithm for upper extremity usage estimation was not decided. At the end of data collection, it was decided to use percentage of active time (time spent over a prespecified threshold), activity count, ratio of high intensity activities (activities in the highest 33% percentile of activity count), ratio of medium intensity activities (activities in the middle 33% percentile of activities) and ratio of low intensity activities (activities in the low 33% percentile of activity counts)
Time frame: Worn every day, but it will be averaged for every week, starting one week before the CSI and ending four weeks after.
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