Coplanar Arrangement of Shortwave Diathermy is the Most Efficient in Skin Temperature Change: A Randomized Crossover Trial
Phase: NA
Conditions: Humans, Young Adult, Health
Sponsor: Alessandro Haupenthal

Title: Coplanar Arrangement Of Shortwave Diathermy Is The Most Efficient In Skin 
Temperature Change: A Randomized Controlled Trial.  
Date: 12-15-2019 
NCT number: NCT03601715 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Study Protocol with Statistical Analysis Plan: 
Study Design  
 
A randomized crossover trial. Using a website (http://www.randomization.com), 
an independent researcher randomly allocated the subjects in three groups with a ratio of 
1:1:1 and block sizes of 18. Then, concealed allocation results in sequentially numbered, 
opaque, sealed envelopes, and placed it in an agreed location.  Another researcher opened 
the envelopes only before the first intervention, in the presence of the subject. Each group 
differs regarding arrangement application order, as follows: group A) coplanar, 
contraplanar and longitudinal; group B) contraplanar, coplanar and longitudinal; group 
C) longitudinal, coplanar and contraplanar. 
 
The same researcher that captured the thermographic images color-coded the 
results, which were given to a blinded researcher for data analyses, who returned it 
afterwards for decoding. The researchers were kept blinded to the process in which they 
did not participate, and the subjects to the intensity indicator monitor.  
Participants 
 
Young health male university students, reached through social media, volunteered 
to participate in the study. Eligible subjects were those that consent in abstain from 
physical activity at least 24 hours prior to the intervention day, and in avoid caffeine, 
alcohol, and food intake at least one hour prior to the intervention. Subjects who injured 
the thigh region in the three months before the study, had circulatory history, cardiac 
pacemakers, metal implants or external fixation6, and self-reported current smoking 
would be excluded.    
Interventions 

 
Each subject attended to three sessions with a washout period of at least 24 hours. 
In order to stabilize body temperature, subjects laid in a relaxed prone position on a 
wooden stretcher, under instruction to refrain from touching the left thigh over the 20 
minutes of acclimatization. Then, the previous determined capacitive technic 
arrangement of SWD was applied for 20 minutes.    
 
The SWD device we used was Diatermede II (Carci® 4022, São Paulo, SP, 
Brazil), on continuous mode, with a frequency of 27.12 MHz. Which was delivered by 
means of two pad electrodes (17x12 cm) surrounded by felt and positioned over 1 cm6 of 
toweling. On coplanar arrangement, the electrodes were as far apart as the cross-sectional 
diameter of the pad electrode (Figure 1). We controlled the intensity based on a referred 
warm heat perception by the subject. The device was calibrated prior to data acquisition.  
 
We measured the temperature in three time points, first: before the application 
(baseline), after acclimatization period, second: immediately after each application, and 
third: each minute over 25 minutes after electrodes removal. We maintained room 
temperature between 23 °C and 25 °C, with a mean humidity of 64% throughout the 
study. The room had no source of infrared radiation or airflow. 
 
Previously to acclimatization period we had marked each 6 cm over 36 cm from 
the base of the patella towards the anterior superior iliac spine. We collected skin 
temperature under the electrode (at the centre of the proximal electrode), and at the thigh 
centre (6 cm from the proximal electrode’s edge). Thus, on coplanar and longitudinal 
arrangement at 18 cm and 30 cm marks, and on contraplanar arrangement at 12 cm and 
24 cm marks (Figure 2).  
Outcomes Measures  

 
The primary endpoint was to determine the most efficient arrangement of 
capacitive technic with respect to temperature change over the 25 minutes after 
application, which was measured in Celsius (°C) on the anterior aspect of the left thigh.   
 
To collect skin temperature we used an SC325 infrared thermography camera 
(A325sc; FLIR Systems, Antennvägen 6, PO Box 7376 SE-187 66 Täby, SWEDEN), 
positioned vertically 1 m from the thigh. The camera was calibrated prior to data 
acquisition. Manufacturers’ specifications defined an accuracy of +/- 2%, and emissivity 
of 0.01 to 1. We analyzed the thermographic images (320 x 240 pixels) using ResearchIR 
software, version 4.40.1.6 (Copyright © 2016 FLIR Systems, FLIR Systems, Inc., 27700 
SW Parkway Avenue, Wilsonville, OR 97070 USA).  
Statistical Analysis  
 
We used descriptive statistics to summarize data, computing means and standard 
deviations (SDs) for the primary endpoint, and the Shapiro-Wilk test for checking data 
normality. To compare the arrangements we conducted a repeated measures analysis of 
variance (ANOVA) and Bonferroni post-hoc tests. The α level was set at <.05. Effect size 
was calculated through partial eta squared and correlated using Cohen index (.1 to .3 as 
small, .3 to .5 as medium, and over .5 as large). In order to summarize the data we 
conducted 5-minute interval analysis. SPSS software (version 20; IBM Corp, Armonk, 
NY) was used for analyzes.