Changes in Intramuscular Blood Volume Induced by Continuous Shortwave Diathermy

The Thermal Influence of an Electromagnetic Field with a Radio Frequency Depending on the Type of Electrode Used

Diathermy is a method used in physiotherapy based on obtaining an increase in temperature by supplying energy from the electromagnetic field to the tissues. The aim of this retrospective work, based on the data included in a medical documentation, was to assess the dynamics of temperature changes on the body surface after the application of a high-frequency electromagnetic field depending on the type of electrode used. In order to generate a radio frequency electromagnetic field, an INDIBA ACTIV® CT9 was used. In order to measure the temperature, an HT-17 thermovision camera was used, enabling measurements within the range of -20 to 300 °C, with an accuracy of ±2% or 2 °C. The participants consisted of 30 healthy subjects (15 women and 15 men) who were physiotherapy students in the Faculty of Public Health in the Silesian Medical University in Katowice, Poland; they were divided into two comparative groups (A and B). It was found that the differences between the groups were not significant in the measurements carried out before using the electrode (p = 0.84; Mann-Whitney U test). On the other hand, at 0, 5 and 15 min, statistically significant differences were noted in the tissue temperature between the groups, depending on the electrode used (p = 0.00; Mann-Whitney U test). Based on the obtained results, it can be concluded that with the extension of the observation time, the tissue temperature increased (for Group A, Me 30.40 °C vs. 34.90 °C; for Group B, Me 30.70 °C vs. 35.20 °C). Our study confirmed that the use of both a capacitive and resistive electrode during treatment with the use of a high-frequency electromagnetic field statistically significantly increased the surface temperature of the area to which the therapy was applied. The results of the study can be used in clinical practice by physiotherapists to optimize the conditions of therapy.

Coplanar arrangement of shortwave diathermy is the most effective in skin temperature change: A randomized crossover trial

INTRODUCTION

Continuous shortwave diathermy (CSWD) efficacy relies on change in temperature, which had been evaluated previously. However, the studies are not comparable enough, consequently the primary goal of this study was to analyze which SWD capacitive technique arrangement is the most effective in skin temperature change.

METHOD

A randomized, single-blinded crossover trial conducted in a university research laboratory. Twenty young healthy male subjects were randomly allocated using a website to receive 20 min of CSWD application to the anterior aspect of the thigh through coplanar, contraplanar and longitudinal arrangement. Skin temperature was collected under the proximal electrode and at the thigh center over 25 min after electrodes removal, using an infrared thermography camera.

RESULTS

There were two losses to follow up, remaining 18 subjects for analysis (age = 21.4 ± 2.09 years, BMI = 23.6 ± 2.46 kg/m²). Under the electrode all arrangements achieved vigorous heating (coplanar = 7.9 ± 1.76 °C; contraplanar = 6.52 ± 2.68 °C; longitudinal = 7.46 ± 1.8 °C) immediately after electrodes removal and temperature decreased with a similar rate across arrangements. At the thigh center, coplanar arrangement achieved mild heating (1-2 °C) until 17 min after electrodes removal; meanwhile, the other arrangements did not increase temperature sufficiently for post intervention therapeutic effects. No unintended effect was detected.

CONCLUSIONS

Coplanar arrangement increased skin temperature the most, heated the greatest area, and had the slowest temperature decay. If the body part accommodates any of the capacitive technique arrangements, coplanar should be used to treat superficial tissues.

Application of shortwave diathermy to lower limb increases arterial blood flow velocity and skin temperature in women: a randomized controlled trial

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The velocity of popliteal artery flow remained unchanged with MWD and increased with SWD, remaining above baseline even 20 min after application.

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Despite changes in blood flow velocity, no correlation was found between the temperature variation and arterial blood flow.

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SWD and MWD both increase skin temperature, but only SWD increased it for over 20 min after the end of application.

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The temperature was greater in the areas under the MWD and SWD electrodes.

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The position of the knee interfered with the skin temperature of the hamstring only after 10 min of SWD application.

Background

Shortwave diathermy (SWD) and microwave diathermy (MWD) are frequently used by physical therapists to treat musculoskeletal conditions. The therapeutic benefits are usually associated with an increase in tissue temperature; however, there is no consensus on the changes in blood flow.

Objectives

1) To evaluate the behavior of temperature and arterial blood flow after the application of SWD and MWD to the lower limb of healthy women aged 18–30 and 2) to assess whether changes in limb positioning can influence SWD response.

Method

Among the subjects analyzed, 40 women were eligible to participate in the trial and were randomly allocated to the SWD group or the MWD group. Each group received 20 min of diathermy. After receiving the interventions, all patients crossed over to the other group, but the devices were detuned (sham). SWD was applied to the posterior compartment of the thigh and leg, with the knee in 0° and 90° of flexion, and the MWD applied to the posterior thigh. Skin temperature evaluation (digital infrared thermography) and assessment of blood flow velocity (Doppler ultrasound) were performed immediately before and 10 and 20 min after the application.

Results

Arterial blood flow increased after SWD diathermy (vs. Sham), but not after MWD diathermy. SWD promoted skin heating at the end of therapy in all areas analyzed, remaining above baseline even 20 min after the end of the application. MWD diathermy promoted skin heating in the posterior thigh, reflecting a rise in the temperature of the popliteal fossa area that remained for 10 min after the end of the application.

Conclusion

The increase in arterial blood flow velocity depends on the size of the heating area, since it was only observed in the application of the SWD. However, after 20 min of application, the position of the lower leg did not affect the heating.

Effects of movement from a postural maintenance position on lumbar hemodynamic changes

[Purpose] To investigate the effects of movement from a postural maintenance position on lumbar hemodynamic changes, in order to prevent lower back pain and develop exercise therapy. [Subjects and Methods] Twenty-five healthy adults (mean age: 23.2 years) participated in the study. During flexion-extension exercise, the subjects moved their trunks gradually to a flexed position from an upright posture while sitting and standing, and then returned to and maintained an upright (re-upright) position. In the extension–flexion exercise, the subjects moved their trunks gradually from an upright posture to an extended position, and back while maintaining an upright (re-upright) position. Lumbar spinal muscle activity and hemodynamic changes were evaluated during both exercises. [Results] During the flexion and extension exercises, increased trunk-flexion angle caused increased muscle activity, decreased oxygenated hemoglobin in the multifidus muscle, and increased deoxygenated hemoglobin in the multifidus and lumbar erector spinae muscles. Moreover, the muscle activities were nearly the same in the re-upright and upright positions, and total hemoglobin also increased. [Conclusion] In both standing and sitting positions, holding the trunk in a flexed position causes ischemic hemodynamic changes in the multifidus muscle; however, the hyperemic response when returning the trunk to an extended position may improve circulation.

Effects of therapeutic ultrasound on intramuscular blood circulation and oxygen dynamics

PURPOSE

This study aimed to clarify the effects of therapeutic ultrasound on intramuscular local blood circulation (and oxygen dynamics) using near-infrared spectroscopy (NIRS).

PARTICIPANTS

The participants were 11 healthy males.

METHODS

All participants performed all three trials; (1) the ultrasound (US group), (2) without powered ultrasound (placebo group), and (3) rest (control group). Ultrasound was applied at 3 MHz, 1.0 W/cm(2), and 100% duty cycle for 10 minutes. Evaluation index were oxygenated, deoxygenated, and total hemoglobin (Hb) concentrations in the intramuscular and skin surface temperature (SST). The experimental protocol was a total of 40 minutes, that is, 10 minutes before trial (rest), 10 minutes during the trial (ultrasound, placebo, and control), and 20 minutes after trial (rest). The NIRS and SST data collected before and after the trial were divided into 5 minutes intervals for further analysis.

RESULTS

Oxygenated and total hemoglobin levels were significantly higher in the US group than in the placebo and control groups for the 20 minutes after ultrasound (p < 0.01). The SST was significantly higher in the US group than in the control for 15 minutes after ultrasound (p < 0.05), while it was significantly lower in the placebo group than in the US and control groups for 20 minutes after the trials (p < 0.01).

CONCLUSION

The effects of ultrasound were maintained for 20 minutes after the trial on intramuscular blood circulation and oxygen dynamics. These effects were caused by a combination of thermal and mechanical effects of the ultrasound.