Pain Reduction and Posture Alignment Improvement in Older Adults with Chronic Low Back Pain: A Novel Approach Using Spinal Thermal Massage Bed and Calf Pneumatic Cell Compression

Background

Population aging is a global phenomenon. According to the United Nations, the world population aged 60 years and over will triple by 2050 [1]. In Korea, it is expected that by 2025, more than 20% of the total population will be over 65 years old, making it a super-aged society [2]. The constant growth of the older adult population and deinstitutionalization increases the need for care services at home in the coming years, as most of this population has one or more chronic disorders [2]. For many of these disorders, there is no cure; thus, management and support must be provided to facilitate the quality of life (QoL) of older generations [3].

Aging can lead to the development of cardiovascular and chronic musculoskeletal degenerative diseases [4]. Changes in the bones, muscles, and joints can lead to alterations in the physiological spinal curvature [5,6]. Most people over 65 years of age are prone to postural deviations that cause variations in muscle activity associated with spinal alignment, such as kyphosis and lordosis [7]. These changes are associated with poor postural control, which increases the risk of pain [8].

Pain is among the most common disorders affecting this population, with a prevalence of 25% to 50% in community-dwelling older adults [9]. Chronic pain that persists or recurs for more than 3 months is known as chronic pain [10]. Approximately 20% to 25% of the population older than 65 years is affected by chronic low back pain (CLBP), currently the main cause of disability in developing and developed countries [11]. CLBP increases linearly from the third decade of life and affects more women than men [12]. It is associated with several adverse outcomes in older adults, such as functional loss, depression, anxiety, social isolation, gait change, falls, low QoL, and higher health costs [10].

Since CLBP usually results in functional disability and QoL reduction, its management in older adults is crucial [13]. Medication, physical therapy (physical agents, massage, muscle strengthening, and posture correction exercises), and surgery are currently used to manage CLBP [14]. However, excessive use of medications can cause several adverse effects, including physical dependence, addiction, gastrointestinal or central nervous system-related adverse events, constipation, nausea, somnolence, and, in some cases, death [15]. Furthermore, while demonstrated to be beneficial, physical therapy or surgical procedures for older adults with poor economic status can be difficult to access, owing to long-term health expenses [16].

Therefore, easy access, reduced adverse effects, and effective methods to treat and manage CLBP in this population are necessary, especially those that can be used at home.

Recently, the spinal thermal massage bed (STMB), a device that combines the effects of massage and thermal functions, has shown the ability to reduce lower back, shoulder, knee, hip, and neck pain [17]. In addition, a study found that its use for a month effectively reduces depression and stress [18]. Based on previous research, the use of STMB has the potential to be an excellent treatment for CLBP in this population.

In addition to STMB, compression therapy, which is the application of modulated pneumatic compression to the calves, improves venous return and blood flow in adult populations [19]. The improvement in venous return and blood circulation combined with the thermal effects of STMB may be favorable for the management of CLBP and improvement of QoL in this population.

To the best of our knowledge, the effects of STMB combined with intermittent pneumatic calf compression on the correction of postural changes related to CLBP, together with changes in pain, have not yet been assessed. In addition, since the use of the STMB combined with intermittent pneumatic calf compression is expected to become a self-treatment for long-term use at home, its safety and participant satisfaction must be assessed.

This preliminary study aimed to assess the effectiveness of STMB combined with intermittent pneumatic calf compression in reducing pain, improving spine posture deviations, lowering stress levels, and enhancing QoL in older adults with CLBP.

Material and Methods

ETHICS STATEMENT:

This study was approved by the Institutional Review Board of Korea University (number KUIRB-2023-0009-0) and registered under number KCT0008212 (https://cris.nih.go.kr/). It was conducted in compliance with the 1964 Declaration of Helsinki guidelines. The participants signed an informed consent form after receiving a general description of the study’s objectives and methodology and any potential discomfort they might experience throughout the intervention. They were free to leave the study at any time without any consequences.

PARTICIPANTS:

The sample size was calculated using G*Power 3.1.9.7 software (Franz Faul, University Kiel, Kiel, Germany), with a type I error rate set at 5%, a desired power of 80%, and an effect size of d 0.65 for 1 group. As a result, a total sample size of 17 participants was estimated to be required to determine differences in outcome measurement scores.

A total of 25 participants were assessed for eligibility, of which 23 met the inclusion criteria. The intervention was completed by 23 participants (6 men, 17 women) aged 65 to 80 years and previously diagnosed with non-specific CLBP by a professional. The following inclusion criteria were used to recruit and select participants: (1) age 65 to 90 years; and (2) CLBP lasting more than 3 months. The exclusion criteria were as follows: (1) cardiovascular and renal disease, (2) neurological disease, and (3) uncontrolled clinical conditions, such as neuropsychiatric disorders.

EXPERIMENTAL DESIGN:

This study used a pre-test–post-test design to evaluate the effectiveness of STMB combined with intermittent pneumatic calf compression to reduce pain and improve body posture. In addition to assessing the treatment’s effect on stress reduction and improving QoL, we assessed its safety. The experiment was conducted at the Korea University R&D Center (Seoul, South Korea), which the participants visited 8 times (twice a week for a month).

STMB WITH INTERMITTENT PNEUMATIC CALF COMPRESSION:

An STMB device with integrated calf pneumatic cells that provide intermittent compression, called MIGUN Re: bone (model MH01-SK0), was used during the intervention. The class II medical device, manufactured by Migun Life Corp, in Seoul, South Korea, was approved by the Korean Ministry of Food and Drug Safety under the number A83060.01.

The STMB device consists of a thermal cushion that contains 2 roller devices, each made up of 5 interconnected jade pieces (Figures 1, 2). The rollers exerted pressure along the length of the spine while oscillating up and down on the bed at a velocity of 100 cm/min. The calf area of the device consists of 16 pneumatic cells that expand and contract based on the compression level selected during the intervention (low, medium, or high) to deliver the desired compression level.

The STMB device included pre-installed massage programs that targeted specific spinal regions by varying the roller speed and restricting massage to the selected areas. The programs were developed on the basis of expert consensus.

INTERVENTION:

The intervention involved 8 sessions of 2 sessions a week over a 4-week period. Pre-installed program number 5 (P5) of the STMB device was used. The P5 program is designed with a bidirectional mode consisting of a total of 12 movements that occur in 3 stages. Each of the 3 stages consist of 4 repetitions at low speed, medium speed, and high speed, respectively. The program was tailored to treat the entire spinal column, delivering a 15-min massage to the spine using heated rollers that moved at a regulated pace, with the pneumatic cell compression therapy set to a level best tolerated by the patient [20]. The temperature of the thermal bed was set to 60°C; however, the temperature received by the skin of the participants was 40°C.

OUTCOME MEASURES:

Clinical and demographic data were collected from all the participants. Outcome measures were obtained at baseline and after the final session. Changes in pain and stress scores were also measured at the end of the second week of the intervention. The outcome measures were performed by 2 physical therapists with over 4 years of experience and expertise with the tests.

PAIN INTENSITY: Pain intensity was evaluated using the visual analog scale (VAS), in which patients indicated the amount of pain experienced at the time of the evaluation. The VAS consisted of bidirectional 100-mm straight lines with 2 labels, namely “no pain” and “worst possible pain” located at each end of the line. Participants were instructed to mark their pain level on a line using a vertical mark [21].

SPINE CURVATURE TILT ANGLE: To measure the spine curvature tilt angle of each participant, a Body Style S-8.0 device (LU Commerce, South Korea) was used to gather data on their posture, which was then analyzed using the Body Style Analyzer (System Software). This measurement device is designed to attach markers to specific body parts, utilizing a single camera to capture images of body shape and posture for subsequent quantification and analysis. It is capable of measuring shoulder tilt, pelvic tilt, leg flexion, leg length discrepancy, left-right body balance, spinal curvature, foot type, cervical tilt, upper body tilt, pelvic anterior-posterior tilt, and other parts. The placement of markers can be adjusted based on the specific area being measured [22]. For the current study, the body markers were placed on the ear lobe, scapular peak, infrascapular angle, anterior superior iliac spine, and posterior superior iliac spine to provide information on spinal alignment in the sagittal plane [23]. The participants were then instructed to stand upright on a posture pad, and side-view photographs were taken for subsequent analysis. The trunk tilt angle was classified as: 15° ≤θ <35° (proper posture), 35° ≤θ <45° (acceptable posture), and θ ≥45° (inadequate posture). Pelvic angle was classified as follows: 0° ≤θ <20° (proper posture), 20° ≤θ ≤25° (acceptable posture), and θ ≥25° (inadequate posture) [24].

STRESS LEVEL: The autonomic nervous system stress levels of the study participants were assessed using the uBioMacpa V70 (BioSense Creative, Korea). This noninvasive device measures the pulse waves of the fingertip capillaries and analyzes the pulse variability of the heart. The body’s stress level was measured using a pulse wave detector, and the average pulse variability signal analysis published by the North American Society of Pacing and Electrophysiology and European Society of Cardiology (Vanderlei et al, 2009) was used to determine the stress level. Participants were instructed to sit still for 2 min and 30 s with their hands fixed on pads, and stress measurements were taken before and after the daily intervention [25].

DISABILITY LEVEL: A reliable Oswestry Disability Index (ODI) was used to evaluate the specific health status of the study participants. The ODI has achieved international recognition and is recognized as a primary outcome measure in low back pain research. The scale includes 1 item assessing pain intensity and 9 items evaluating the degree of physical activity limitations due to pain. The final score was calculated by dividing the total score by 5 times the number of item responses, then multiplying by 100% [26]. A higher score indicates greater disability [27]. A validated Korean version of the ODI was used [28].

QUALITY OF LIFE: The EuroQol 5-dimension QoL questionnaire (EQ-5D) was used to identify the health status and QoL of the study participants. The EQ-5D was subdivided into 5 questions on mobility, self-care, daily activities, pain/discomfort, and anxiety/depression. The quality weight for the overall health status of EQ-5D was calculated using the final estimation formula to predict the health status quality weight of the EQ-5D for Korean Nationals; the maximum score of 1 indicates the best health state [29].

SAFETY AND PARTICIPANT SATISFACTION ASSESSMENT:

At the end of the study, participants were asked to complete an anonymous survey about their experiences during the study. The participants were asked to describe the sensations they perceived during the STMB application. The survey asked about the presence of any adverse effects during and after the intervention as well as the overall satisfaction with the STMB combined with intermittent pneumatic calf compression intervention.

STATISTICAL ANALYSIS:

All statistical analyses were performed using SPSS Statistics for Windows version 28 (IBM Corp., Armonk, NY, USA). The data are presented as mean±SD. The Shapiro-Wilk test was used to examine data normality. The body style and stress data were normally distributed; therefore, the paired sample test was used for intragroup analyses, with the significance level set at P<0.05. The VAS, ODI, and EQ-5D scores showed no normal distributions. Therefore, non-parametric tests were used to determine the statistically significant effects over time, using the Friedman test. The post hoc analysis was completed using the Wilcoxon signed-rank test, with the significance level set at P<0.05.

Results

Primary Outcomes

PAIN INTENSITY: The Friedman test revealed significant differences between the VAS baseline, mid-term, and post-test scores with χ2 (2)=16.900, P<0.01. The Wilcoxon signed-rank test showed a significant reduction only between the baseline and mid-term scores (Z=−3.025, P=0.002) and the baseline and post-test scores (Z=−3.301, P=0.001) (Figure 3).

SPINE CURVATURE TILT ANGLE: The paired t test showed the trunk tilting angle improved significantly from baseline to post-test, t (22)=5.945, P<0.001 (95% confidence interval [CI], 1.39–2.92). In the case of pelvic tilting, the angle improved significantly from baseline to post-test, t (22)=5.889, P<0.001; 95% CI, 2.59–5.41) (Figure 3).

STRESS LEVEL: The paired t test showed the stress scores were reduced significantly from baseline to mid-test t (22)=2.286, P=0.037 (95% CI, 0.47–13.71) and from baseline to post-test t (22)=2.708, P=0.019 (95% CI, 1.74–16.12). However, there was no significant difference between the mid-test and post-test values (Figure 3).

DISABILITY LEVEL:

The Wilcoxon signed-rank test showed no significant changes between baseline and post-test scores (Z=−987, P=0.49).

QUALITY OF LIFE:

The Wilcoxon signed-rank test showed no significant changes between baseline and post-test scores (Z=−1.379, P=0.17).

SAFETY AND PARTICIPANT SATISFACTION ASSESSMENT:

There were no serious adverse effects, such as dizziness, headache, redness, or dangerous temperature increase, during and after the application of the STMB. One participant reported experiencing dizziness after using the device; however, it disappeared quickly thereafter. In addition, 2 participants reported that the sensation of roller massages on the lower back was uncomfortable but disappeared during the 15-min intervention without any lasting additional sensations.

The survey revealed that >80% of the participants were satisfied with the STMB combined with intermittent pneumatic calf compression, 20 participants reported that the intervention effectively reduced pain. In addition, 19 participants showed willingness to buy the device for use at home. However, 10 participants reported recommending the application of the STMB P5 program for a longer period, specifically for 30 to 40 min.

Discussion

The present study aimed to determine whether STMB combined with intermittent pneumatic calf compression is effective at reducing pain, improving body posture, reducing stress, and improving QoL while assessing its safety. Our findings suggest that 8 sessions of STMB over a 4-week period effectively reduced pain, improved posture, and reduced stress. Although the changes in the ODI and EQ-5D were not significant, the results showed a tendency to improve compared with baseline.

The significant reduction in pain scores observed in this study is consistent with that in previous research. In a study conducted in 2020, similar findings were reported, demonstrating a significant decrease in back pain among older adults following the utilization of a similar STMB device [17]. Likewise, another study indicated that massage chair therapy, which also incorporated thermal effects, effectively reduced back pain in an adult population. However, it was not as effective as conservative therapy [30].

These positive changes in pain scores can be explained by various factors. First, massage-like longitudinal mechanical pressure provides analgesic effects via the ascending pain inhibitory system (gate theory of pain) [31]. The activation of thick myelinated ergoreceptor nerve fibers (via activation of percutaneous mechanoreceptors and proprioceptors) can alter the transmission of ascending nociceptive information via small-diameter Aδ fibers and induce a descending inhibitory effect that allows the modulation of pain perception [32].

Second, the thermal effects delivered by the bed heating system elevate the core body temperature and blood circulation through vasodilation and metabolic activation and improve tissue regeneration [18]. In addition, combination therapy with compression therapy reportedly increases muscle blood flow and accelerates the delivery of oxygen, influencing the increase in muscle temperature and blood pH, thereby reducing calcium deposits in the musculature, and inhibiting swelling and muscle tone decreases [18,19].

Changes in the trunk and pelvic tilt angle are related to pain reduction. STMB combined with compression therapy improves circulation, reduces muscle tension, and promotes relaxation of the muscles and soft tissues of the back, which could contribute to improved posture over time [33]. A study showed that patients with scoliosis experienced improvement of the Cobb angle after the use of STMB at home [33]. Posterior to anterior traction was generated by the device. The posterior to anterior traction direction in the extended supine position was studied by mechanically lifting the vertebral segments locally using a similar STMB device in healthy participants. The average height values of the intervertebral space between the L3–4 and L4–5 segments significantly increased under traction. Increases in the anterior, central, and average height of the intervertebral space indicate expansion of the intervertebral space [34].

The results also showed a significant change in stress scores, which correlated with the pain reduction scores, and aligns with previous research in which similar equipment was used in middle-aged individuals with muscle pain in one or more areas of the shoulder, back, and waist. Their findings indicate an effective reduction in pain and stress levels [18].

Pain can activate the body’s major stress response system, the hypothalamic-pituitary-adrenal axis, to release the stress hormone cortisol [35]. After pain was reduced due to STMB combined with intermittent pneumatic calf compression therapy, cortisol levels were expected to decrease. Another study investigated the stress-alleviating effects of massage therapy and revealed decreased cortisol levels and increased serotonin and dopamine levels [36].

The results of the present study showed a non-significant increase between the mid-test and post-test scores; however, compared with baseline, both results were still significant. This may have occurred because of external conditions, such as socioeconomic difficulties. In addition, the pain scores continued to decrease, indicating that the stress levels were probably influenced by other factors.

Furthermore, the QoL and disability scores tended to improve with changes in the mean scores, although these changes were not significant. We believe that the improvement in the pain scores promoted a slight improvement in the scales; however, the participants initially had scores that denoted good QoL and minimal disability levels; therefore, no dramatic changes were expected. However, the short intervention period may have been insufficient to induce changes in these scores. A recent study found that a significant change in QoL was only noticeable after 6 months of conservative or surgical treatment in a population with degenerative stenosis of the lumbosacral spine, despite achieving pain reduction before 6 months [37].

It is important to highlight this study’s strengths, which were that it demonstrated that using the STMB had an early effect on pain management and that it can positively influence spine curvatures to reduce the structure deformations typical of aging. The study’s long-term goal is to continue exploring the effects of the STMB device on QoL in order to use the device as a home therapy for the elderly in the future. In addition, other populations that may benefit from the STMB device will be studied in the near future.

Given the global increase in the elderly population, it is essential to prioritize studies that focus on sustainable, long-term approaches for pain and posture management in this demographic. Emphasizing home healthcare for the elderly is crucial for ensuring improved QoL in the coming years.

The main limitation of this study was the imbalance in the biological sex of the participants and the absence of a control group. Future research should focus on a larger and more variable population. Another limitation was the short intervention period; it is recommended to apply the intervention during longer periods to determine its long-term effect.

Conclusions

In conclusion, this study provides evidence that the use of STMB with intermittent pneumatic calf compression effectively reduces pain intensity and stress levels while improving trunk and pelvic tilting angles. The intervention was well received, with over 80% of participants expressing satisfaction, and no serious adverse effects were reported, indicating its safety and tolerability. These results indicate the potential value of combined STMB and intermittent pneumatic calf compression as an intervention for individuals with pain and postural issues. Further research should investigate the optimal duration, frequency, and long-term effects of this intervention on pain and postural issues.