Comparison of UNIQ and classic unipolar electrodes in TECAR therapy for low back pain: a retrospective cohort study

Abstract

[Purpose] Low back pain (LBP) affects millions worldwide and frequently becomes chronic, diminishing quality of life. TECAR therapy is a non-invasive intervention that applies radiofrequency currents to heat tissues, reduce spasms, and enhance circulation. This study aimed to evaluate a novel electrode integrating resistive and capacitive mechanisms to determine its efficacy in managing LBP with TECAR therapy. [Participants and Methods] Fifty-two patients were assessed at baseline (T0) and after a 2-week treatment period (T1) and received TECAR therapy with either a conventional electrode or the UNIQ electrode. Pain intensity was measured with the Visual Analogue Scale, lumbar mobility by active range of motion in flexion and extension, and disability using the Roland–Morris Disability Questionnaire. [Results] The treated group showed ΔVAS values of −6.00 ± 1.50 cm compared with −3.17 ± 1.85 cm in the control group. For lumbar range of motion, ΔROM was −1.75 ± 0.87 in the treated group and −1.16 ± 1.27 in the control group. Disability scores were −11.47 ± 4.81 in the treated group and −5.53 ± 4.21 in the control group. [Conclusion] These findings indicate that combining resistive and capacitive electrodes may increase the therapeutic effectiveness of TECAR therapy for managing low back pain.

INTRODUCTION

Low back pain (LBP) is a highly prevalent condition among adults, accounting for 36.8% of musculoskeletal disorders globally in 2017¹⁾. Approximately 619 million individuals, particularly those who are middle-aged, are affected, making LBP a major health and economic concern. Since LBP is frequently associated with chronic or temporary disability and loss of productivity, it imposes a substantial financial burden on individuals and societies (WHO). LBP is defined as pain or discomfort in the lumbosacral region, below the last rib and above the gluteal crease, with or without referred leg pain. It commonly arises from degenerative changes in the lumbar spine, muscles, or ligaments, as well as from injuries²⁾. In many cases, the specific nociceptive source is not identified, and the condition is therefore classified as “nonspecific LBP.” Approximately 90–95% of cases fall into this category, while <1% involve specific spinal pathology and 5–10% present with radicular syndrome^{3, 4)}.

The global prevalence of LBP that restricts daily activities for >1 day is estimated at 12%⁵⁾. While most individuals experience rapid improvement in pain and disability within the first month of acute LBP, 4–25% progress to chronicity. The prevalence of chronic low back pain (CLBP) rises steadily from the third decade of life until around 60 years, with a higher prevalence in females⁶⁾. Ultimately, LBP compromises functionality and leads to a marked decline in patients’ quality of life. Specific treatments are indicated only for patients with clinically significant neural compression or systemic conditions such as cancer, infection, visceral disease, or spondyloarthritis. In most cases, nonspecific LBP is managed conservatively, with treatment aimed at pain reduction and functional restoration. Such approaches include behavioural education and physical therapy⁷⁾.

In recent years, capacitive and resistive electric transfer (TECAR) therapy has gained popularity in musculoskeletal care. TECAR therapy, representing an advancement over diathermy, is a non-invasive endogenous thermotherapy that applies radiofrequency currents to warm deep tissues. This process is controlled to avoid hyperthermia in surrounding tissues, thereby reducing the risk of increased inflammation or skin burns⁸⁾. Treatment can be performed in capacitive or resistive mode depending on tissue resistance, using stainless steel electrodes with an electromagnetic frequency typically between 300 kHz and 1.2 MHz^{9, 10)}. In capacitive mode, the electrode is coated with an insulating ceramic layer acting as a dielectric, producing heat in superficial tissues. This is more effective in water-rich structures such as muscles, cartilage, adipose tissue, and lymphatic vessels. In resistive mode, the uncoated electrode allows the electromagnetic wave to penetrate more deeply, targeting water-poor tissues such as bone, tendons, muscular fascia, and capsules¹⁴⁾. TECAR therapy reduces spasms and activity-induced contractions, improves blood flow, enhances muscle oxygenation through haemoglobin activation, stimulates endorphin release, and increases cellular metabolism^{12, 13)}.

The beneficial effects of TECAR therapy in musculoskeletal disorders, particularly LBP, have been demonstrated in several studies^{4, 11, 12, 14)}. Recently, a new electrode has been developed, enabling simultaneous capacitive and resistive application within a single instrument. This facilitates a more reliable and practical application of electrodes to the body, resulting in more efficient treatment.

The purpose of this retrospective study is to clarify the differences in clinical effectiveness between a novel combined capacitive–resistive electrode (UNIQ) and a traditional monopolar electrode in the treatment of low back pain.

PARTICIPANTS AND METHODS

In this retrospective study, data from patients treated between January and December 2022 at two centres—Ti Riabilita Studio (Sarzana, Italy) and Ars Fisio (Grottarossa, Rome, Italy)—were collected and analysed. A total of 50 participants met the study criteria: 25 in the treated group and 25 in the control group. Patients’ demographic and baseline characteristics, including age, and sex distribution are summarised in Table 1.

Table 1. Baseline demographic characteristics of participants in the control and treated groups.

	Control	Treated
Age (years) (mean ± SD)	51.23 ± 16.8	51.20 ± 14.3
Sex (M/F %)	42 M/58 F	40 M/60 F
N	25	25

M: male; F: female; SD: standard deviation; N: number.

Only data from patient with age ≥18 years and a VAS score ≥6 cm were analysed. Moreover, only data from patients naive to TECAR therapy and not receiving concurrent physiotherapy treatments (e.g., diathermy, laser therapy) were included.

Participants underwent TECAR therapy according to group allocation. Treated group: Patients received therapy with Fisiowarm 7.0 using the new capacitive/resistive UNIQ electrode (Fisiowarm 7.0, Golden Star Srl, Rome, Italy). Treatment was delivered for 15 minutes at a frequency of 300 kHz. Control group: Patients were treated with a conventional monopolar electrode (Activ CT8 INDIBA^®, Rome, Italy), applied at 448 kHz in both resistive and capacitive modes. Each mode was delivered for 10 minutes using two different electrodes. Both groups completed two TECAR therapy sessions per week for two consecutive weeks. Three clinical outcomes were evaluated at baseline and after two weeks of treatment: (1) Pain intensity, assessed using the Visual Analogue Scale (VAS), a 10-cm line on which patients indicate their perceived pain level; (2) Lumbar mobility, measured via the Schober test¹⁵⁾ which quantifies the change in lumbar flexion by evaluating the variation in distance between two marked points on the lower back during forward bending; (3) Disability, assessed using the Roland–Morris Disability Questionnaire¹⁶⁾, a 24-item self-reported tool that measures the impact of low back pain on daily functioning.

This study was registered on ClinicalTrials.gov (registration number NCT06728215). Ethics approval was not required, as this retrospective analysis used anonymised data. The study adhered to the principles of the Declaration of Helsinki (2024).

Data are expressed as mean ± standard deviation (SD). Continuous variables were assessed for outliers and extreme values. Following standard observational study practice, identified outliers were excluded to minimise the influence of aberrant data. Treatment effects were evaluated using the Mann–Whitney nonparametric test. Statistical significance was set at p<0.05. To quantify the magnitude of the difference, we computed Hedges’ g using group means and pooled standard deviations, as recommended for unequal sample sizes. All analyses were performed using GraphPad Prism 8 (GraphPad Software, San Diego, CA, USA).

RESULTS

To account for within-subject variability, treatment effects were assessed using Δ values (T1 − T0), which provide a robust and assumption-free measure of change.

Pain intensity showed a reduction in the treated group. In particular, ΔVAS was −6.00 ± 1.50 cm in treated participants compared with −3.17 ± 1.85 cm in controls (p<0.001; Hedges’ g=1.73) (Table 2).

Table 2. Changes in VAS, ROM, and Roland–Morris scores after treatment in the control and treatment groups.

		Δ Control	Δ Treated	ΔCTR vs. TRT
VAS (cm)	N	14	25
	mean ± SD	−3.17 ± 1.85	−6 ± 1.50	****
ROM (°)	N	14	24
	mean ± SD	−1.16 ± 1.27	−1.75 ± 0.87	*
ROLAND MORRIS (score)	N	13	17
	mean ± SD	−5.53 ± 4.21	−11.47 ± 4.81	**

Significance levels: *p<0.05; **p<0.01; ***p<0.001; ****p<0.0001. Values are expressed as mean ± SD. Δ indicates the change between baseline and post-treatment values (T1–T0). VAS: visual analogue scale; ROM: range of motion; SD: standard deviation; N: number; CTR: control group; TRT: treatment group; T0: baseline (before treatment); T1: post-treatment.

A similar pattern was observed for lumbar range of motion, with treated participants showing a larger improvement (Δ=−1.75 ± 0.87°) than controls (Δ=−1.16 ± 1.27°; p<0.05 ; Hedges’ g=0.57) (Table 2).

Functional disability, assessed through the Roland–Morris questionnaire, also improved more in the treated group. ΔRoland–Morris scores were −11.47 ± 4.81 in treated participants and −5.53 ± 4.21 in controls (p<0.01; Hedges’ g=0.51) (Table 2).

DISCUSSION

In this article, we evaluated cohort data on TECAR therapy delivered through two different devices. The innovative device allows simultaneous treatment with capacitive and resistive electrodes, whereas the standard device provides sequential treatments (capacitive followed by resistive).

TECAR therapy is recognised for its effectiveness in both healthy and pathological musculoskeletal conditions. The most consistent benefits have been reported in pain reduction, improvement of joint or muscle function, and increased tissue mobility and flexibility. These effects are largely attributed to heat generated during therapy¹⁷⁾. Heat stimulates circulation in superficial and deep tissues, promotes tissue relaxation, and enhances fluid drainage¹⁷⁾. Additional benefits include increased blood flow and oxygenation, improved haemoglobin saturation, and more efficient removal of metabolic waste^18,19,20,21). Overall, these mechanisms contribute to the clinically beneficial outcomes of TECAR therapy.

Evidence indicates that a combined capacitive–resistive approach can improve blood flow and tissue temperature without excessive skin heating⁴⁾. Elhosary et al. reported that this method induces a thermotherapeutic effect in deep tissues such as muscles and tendons, while maintaining tolerable skin temperatures²²⁾. This characteristic is particularly advantageous for patients sensitive to heat or at risk of conditions aggravated by superficial heating.

Standard TECAR therapy for LBP is typically structured into two treatment phases: capacitive, which targets superficial tissue layers, and resistive, which penetrates deeper structures. The present findings suggest that a combined modality, applying both electrodes simultaneously, may enhance therapeutic efficacy by addressing superficial and deep tissues concurrently.

Our results indicate that this combined approach may yield improved outcomes within 2 weeks, including significant pain reduction and greater joint mobility. Patient-reported outcomes also suggest an improved perception of quality of life. Such innovative applications of TECAR therapy could therefore transform the management of LBP and support more effective rehabilitative practices. Patients may therefore benefit from stronger analgesic effects, reduced oedema, diminished inflammation, and enhanced myorelaxation. Moreover, the reduced treatment time (15’ with the new electrode versus 20’ with the standard device) could improve patient compliance.

The synergy between electrode design and multifaceted stimulation may optimise patient outcomes, further strengthening TECAR therapy as a valuable clinical tool. This advancement also creates opportunities for broader applications in pain management and rehabilitation, with potential implications for physiotherapy and sports medicine.

This study was intended to provide preliminary evidence of the clinical benefits of this combined electrode and to guide the design of future structured clinical trials.

This study has several limitations. Its retrospective design and lack of randomization introduce potential selection bias and prevent firm causal conclusions. Residual confounding is possible, particularly because certain relevant clinical variables—such as height, weight, and BMI—were not collected and therefore could not be controlled for in the analyses. The modest sample size may limit statistical power, and the single-center setting reduces generalizability. Future prospective studies with larger sample sizes and more comprehensive baseline data, ideally using randomized designs, are needed to confirm these findings and strengthen external validity.

In conclusion, the findings suggest that TECAR therapy delivered through a combined capacitive–resistive electrode may be more effective than sequential application with two separate electrodes, offering a promising development for enhancing therapeutic outcomes.

Funding

This study received no specific grant or funding.

Conflict of interest

The authors declare no conflicts of interest.