Efficiency of physiotherapy treatments for low back pain in women : a randomized controlled trial.

List of authors and e-mail addresses:

Poblet Romeo, Ester, PhD 1, 2, *

: ester.poblet@urv.cat

Romeu Ferran, Marta, PhD 2, *

: marta.romeu@urv.cat

Nogués Llort, Rosa, PhD 2

: mariarosa.nogues@urv.cat

Giralt Batista, Montserrat, MD, PhD 2

: montse.giralt@urv.cat

Institutional addresses:

1Rehabilitation unit, physiotherapy and speech therapy from Cambrils Slight Hospital,

Tarragona, Spain

2Unit of Pharmacology, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili,

Reus, Spain

*Corresponding author:

E-mail address: ester.poblet@urv.cat

ABSTRACT:

Background: 79% of menopausal women suffer from low back pain. Therapies such as Transcuta-neous Electrical Neurological Stimulation (TENS), Electromagnetic Therapy and Back School are being used in to treat this disease. However, there is small scientific evidence supporting their use.

Objectives: To evaluate and compare the effectiveness of a combined treatment of TENS or Electromagnetic and Back School with the effectiveness of only the Back School treatment.

Methodology: Prospective, single blind experimental study consisting in the clinic intervention (20 sessions) on 96 women (50-85 years) with chronic low back pathology.

The intensity of pain (VAS Scale) and the quality of life (Oswestry Scale) were measured, at the beginning and at the end of the treatment and after three and six months. Anthropometric and physical activity variables were collected.

Subjects were divided into three randomized groups:

Back School (group 1), TENS with Back School (group 2), and Magnetic therapy with Back School (group 3).

Results: All the groups had better VAS and Oswertry indexes at the end of the treatment (p<0.001).

Group 1 obtained a higher improvement in VAS (p=0.015), and Oswestry (p=0,007) than the other groups. After three months the group 1 obtained more improvement in VAS (p<0,001) than the others, in ODI the group 1 presented a more improvement than the group 2, and the group 3 from the group 2 (p<0.001). At six months the group 1 improved more than the group 2 in VAS (p=0.015) and in Oswestry (p= 0.003).

The previous quality of life of the women who were more active was higher (p<0.05). However, sedentary women presented a higher improvement of their quality life at the end of the treatment (p= 0.001).

Conclusions: The three treatments improved the pain and quality of life. The Back School treatment obtains better results and those results are maintained more effectively at three and six months. This treatment is also the less expensive. Physical activity improves quality of life.

Key words: low back pain, Transcutaneous Electrical Neurological Stimulation, Electromagnetic fields, Back School. Trial Registration: ClinicalTrials.gov NCT01899469.

BACKGROUND:

Low back pain (LBP) affects over 85 % of after-65-aged people at some stage of their lives, and over 79% of menopausal women, in the ageing process it can proceed from different origins: an organic alteration of the back spine, a consequence to osteoporosis or a bad muscular operating, due to physical inactivity and lack of exercise, being the last one the main origin [1]. Muscle contractures, due to a bad muscular operating, can be reversed and the muscle trained at any age with an adequate exercise program in order to avoid a later LBP [2].

LBP can have negative consequences for aged people, who decrease physical activity (PA) due to the pain, so osteoporosis and muscular atrophy increase; even more in women in who the added component of menopause increases the risk of suffering from this illness at an earlier age than usual [3]. To prevent LBP it is useful and necessary to know and follow postural hygienic rules, to keep your back muscles in optimum quality, to avoid an excessive rest and to keep a good PA [4].

Lots of treatments on people with LBP have been evaluated in physiotherapy, but the comparison among different treatments has rarely proved significant differences. One of the reasons is the heterogeneity of the patients in these studies, which can reduce the possibilities of finding a clinically significant treatment, especially in aged people [5].

One of these treatments is Transcutaneous Electrical Neurological Stimulation (TENS), which effectiveness is attributed to Gate's 'Control of Pain' theory [6], and to endogenous endorphin secretion, TENS uses low energy levels applied to painful areas to blockade or reduce the nervous signs of pain [7].

Another technique used is Electromagnetic Therapy (EM), which acts by increasing sensibility to pain threshold and activating anticoagulant system [8]. Back Schools (BS) recognized in chronic LBP a mechanical origin, due to an imbalance between functional load and functional capacity, they are also preventive, and support themselves on a rachis and back economy.

Regarding BS, some studies find positive effectiveness of BS in short term [4, 9, 10], but a recent review doesn’t find any difference between BS, PA and TENS therapy, among others [11]. It is mostly concluded to be a high heterogeneity in the studied groups, which clinical relevance is not enough.

On TENS treatments different authors find a positive relation in LBP and pain decreasing, but they state than proves are not consistent enough and suggest a lack of evidence to support its use [12-14]. Otherwise, there's a clinical study where positive TENS effect is found for a 20-minute-period in LBP [15] and on a revision on different clinical studies on this pathology, TENS is recommended as a decreasing in pain in women, in a 4- week- treatment [3].

EM has achieved to demonstrate consistent improvement from a statistic point of view, as well in pain as in functional capacity; the frequencies lower than 100 Hz and the intensities lower than 100 gauss, have delivered the best results in the widest range of applications [8]. In EM we find one study talking about the benefits in chronic pain and it establishes a daily 20 minutes treatment for 3 or 4 weeks [16]. At the moment there's a multicentre study investigating different protocols to treat LBP where this technique is included, but there's no result yet [5].

Where a positive relation has been found is between previous, along or later PA and LBP, people physically active recover before and have less relapses [17-18]. Many of the reviewed articles discuss the lack of homogeneous studies in this area.

This is one of the reasons because we have decided to conduct the clinical study on a group of women. The main aim of this study was to evaluate and compare the effectiveness in decreasing of low back pain from three treatments in women over 50 with lumbar disease: conventional treatment of TENS combined with Back School, EM combined with Back School and Back School.

The seconds aims was to observe if there is a relationship between the level of previous physical activity and perception of low back pain and to observe if there is a relationship between body weight and perception of low back pain.

We have compared the three treatments and we have observed if there’s a relationship between previous exercise and body mass index with the incidence of low back pain and recovery time. The results of our study will allow to research more treatments of physiotherapy in women with chronic low back pain, in order to define an elective treatment in clinical practice and to define a prevention sanitary programme.

METHODS Study design and Participants In this single-blind, randomized, controlled trial, the BS intervention was compared with EM with BS intervention and the usual TENS with BS intervention. A total of 184 patients were evaluated, 111 of them were enrolled in the study to carry out the inclusion criteria: Women between 50 and 85 years, chronic LBP condition for at least three months ago and the patient’s agreement by signing the consent.

Patients were excluded in case of: Cardiac pacemaker carriers, parts of osteosynthesis and / or prostheses, patients with a not well balanced medical condition, with TENS at home and / or having completed physiotherapy during the last three months, with skin infectious diseases or skin lesions and / or areas of hypoesthesia, with malignant tumors, patients who received any spinal injection during the last six weeks or who participate or have participated in a study in the last three months.

The collecting data and the interventions of the study were carried out in the Physiotherapy and speech therapy unit from Cambrils Slight Hospital. The study was approved by the local ethics committee at the Reus University St.Joan Hospital and was carried out in accordance with the principles of the Declaration of Helsinki. Neither the researcher nor the patients participating in the study will receive any financial consideration.

Interventions Patients were distributed in three treatment groups. We gave a participant number on a chronological allocation, and each participant number was assigned a randomized number (1, 2 or 3), which indicates the type of treatment. The group 1 performed 20 sessions of BS, the group 2 performed 20 sessions of TENS therapy for 20 minutes, and the group 3 performed 20 sessions of EM therapy for 20 minutes. The groups 2 and 3 had a BS intervention after each session therapy. It was a daily treatment, Monday to Friday for 4 weeks (20 sessions).

The group 2 performed TENS therapy using MEGASONIC 313 P4 from Carin, a multi-channel programmable portable muscular stimulator, for analgesia and incontinence, the program applied was number 17 (1 Phase) of analgesic TENS trains release of endorphins, which has the following parameters: Offset asymmetric current, 100μs of impulse width, 80Hz of impulse frequency, use of rail, 0.2s of train ON, paused and without synchronism check.

The group 3 performed EM therapy using PMT quattro PRO from ASALASER, an electro medical equipment for therapy conducting with low frequency magnetic fields, applying program number 42, back pain default patterned, which has the following parameters: 10Hz of frequency and 60% of intensity. The BS performance was held by all patients, the exercises were based on the re-education of breathing, self stretching trunk muscles, erector spine reinforcement, abdominal reinforcement and postural exercises. The exercises are collected in a factsheet for the patient that also includes patient measurements and posture advice. The participants performed 8 to 10 repetitions of each exercise and they were recommended about making a series more at home. The exercises took place mostly on a carpet on the floor, and they were controlled by the physiotherapist.

Pain was measured at the beginning and after the treatment with the Visual Scale Analogue (VAS), an accepted method for measuring pain intensity. The VAS scale represents the pain intensity on a line of 10 cm, at one end there are the words "no pain" and the other end "the worst imaginable pain " written, the distance in centimetres from the "no pain" point to the place marked by the patient represents the intensity of pain [19].

Quality of Life was measured with Oswestry Scale (ODI), is an autoaplicate questionnaire with 6 answers possibilities from 0 to 5, from minor to major limitation. The high punctuation is 50 points. When one question doesn’t have an answer is excluded from the total punctuation resting 5 points. The total punctuation is expressed in % from 0 to 100%. The first question is about the intensity of the pain with or without pharmacy, the second ones are about the pain limitations on activities of the dairy life: personal care, travel, social relations, work….). After the calculations, ODI give us the functional limitation of every participant:

 0-20%: Minimal functional limitation.  20-40%: Moderated functional limitation.  40-60%: Intense functional limitation.  60-80%: Incapacity.  More of 80%: Maxim functional limitation.

We recorded age, Body Mass Index (BMI) from data of the clinical story, and the previous PA. On the basis of BMI, subjects were classified as Obesity (BMI over 30), overweight (BMI between 25 and 29.9) or normal weight (BMI between 18.5 and 24.9) [20]. PA was measured with a method developed by the Health Department of the Catalan Government (ClassAF).

The ClassAF is a Fast Sorter Physical Activity with a comprehensive questionnaire containing a few items (1-4) to measure the general level of PA, it is calculated in METS (basal metabolic expenditure: mlO2/kg.min) and it allows to classify people into physically active or physically inactive using a qualitative formula that contains information about the physical activity at home or at work, from the physical activity in leisure time including competitive sports, and the frequency weekly physical activity leisure, finally the qualitative formula distributed the people in Sedentary, Minimally Active, Lightly Active, Moderately Active and Very Active [21].

All of the assessments were performed by the same physiotherapist.

others, in ODI the group 1 presented a more improvement than the group 2, and the group 3 from the group 2 (p<0.001). At six months the group 1 improved more than the group 2 in VAS(p=0.015) and in Oswestry (p= 0.003).

If we compare the three groups, there are a significant difference between treatments on VAS, the BS group get a significant improvement than others (p=0.015), and also in Oswestry (p=0.007).

To analyze the improvement in pain between the start and end of treatment, the variable differences between VAS were calculated in each group of PA or BMI. The Fast Sorter Physical Activity (PA) has classified the 76.5% of patients in moderately or very active. At the beginning of the treatment the perception of pain doesn’t have a significant difference between groups, but we find these difference on ODI, the quality of live increases as the previous PA of the patients increases, that is, the more active they are initially has best quality of life than others (p=0.003). At the end of treatment, we doesn’t find differences on pain again, but on quality of life we find a significant difference (p=0.001) between Sedentary women and more active women, that is, the sedentary women has more improve on quality of life than others.

Respect de BMI values, we don’t see a significant lineal relationship between the degree of obesity and the perception of pain or ODI values, before and after the treatment.

Respect the diagnostic; we don’t see a significant improvement on the perception of pain or ODI values, before and after the treatment.

Finally, all the participants improve the perception of pain at the end of the treatment, independent the pharmacy dose. However, the group without pharmacy had more improve on pain (p=0.052), on EM group this difference is clearest significant (p=0,015).

All the participants improve the ODI values at the end of the treatment, independent the pharmacy dose. The pharmacy dose doesn’t have effect on quality of live because don’t find significant differences. During the 20 sessions we haven’t detected any adverse effects related with TENS or EM treatment, so the tolerance to the treatment methods has been good. The average assistance of patients at treatment sessions has been ≥ 85% (17 sessions).

DISCUSSION

In this randomized study it can be seen that the use of EM or TENS with BS, or only BS,shows beneficial effects in the reduction of pain and on the quality of life. However, we see differences when comparing the three treatments and we can justify a preferential clinical use of BS treatment, also, is the cheaper treatment, easy to make it at home, and a type of treatment that is possible to include on prevention planes of safe in sanitary centers. Addition, the training of workers is minimum.

In our study, we don’t found a significant correlation between pain and PA.

However, we found a significant result with ODI, we can affirm the women who practice PA have better quality of life than sedentary women, and if they have a posteriori an episode of low back pain, also have a better recuperation. The most important limiting factor of the study is that it has been done only on women between 50 and 85 years, therefore the results cannot be extrapolated to other population.

In addition, the subgroups established by the PA and the BMI, don’t have a size enough to obtain meaningful results from the statistical point of view.

In our study, the number of sessions and their duration of EM were established according to a previous study carried out by Mitbreit et al., one of the first to set an EM treatment 20 minutes long for 20-25 days to proving an improvement of the pain [16].

Later, at 2005, Langford studied the treatment of chronic low back pain by EM and achieved a reduction in pain intensity, but the optimal dose of EM is not very well known [22]. We used a dose with a frequency of 10Hz and an intensity of 60% following the established default protocol for LBP, by the trading house of the used device.

There is evidence that EM really changes the brain wave activity, this suggest that there is a direct effect on central nervous system [23], obtaining a beneficial effect on the decreasing of pain. In our study we have seen this beneficial effect using EM on LBP.

In a systematic review of 2005 [12], the authors give reliability to only 2 of 47 clinical trials which investigated the effects of TENS in chronic LBP, the discarded studies had defaults in the experimental design. Other studies can find no enough evidence to justify the use of TENS in LBP. [24]

In our study, the intensity applied on TENS has been of 80Hz of frequency impulse, 100μs of width impulse with trains of 0.2 s, following the established default protocol in chronic pain, by the trading house of the used device. There is one study that considers the TENS application with parameters between 80-100Hz and 100-200μs as an effective dose [25].

However, a subsequent review in 2008 noted at that time, some clinical studies had been done to begin to establish the appropriate stimulation parameters for an improvement in the reduction of the pain. The best results were found using TENS with high frequency intensity of 100Hz; therefore, it seems that intensity is a critical factor for the effectiveness of TENS, which is due to the poverty of the design of the studies reviewed in their work and in small size samples [24]. In our study the application of this dose of TENS is effective to improve the reduction of pain.

We can see on the literature, that the results on the application of TENS or EM in chronic LBP are not homogeneous neither on doses nor on patient profiles, the findings of our study should be limited to the mentioned doses and on women.

In our study, the patients who practice PA and have subsequently an episode of LBP, have a more satisfactory recovery than people who are sedentary, even we did not see a relationship between a higher initial pain and inactivity.

This relationship exists on quality of life, more active women have best quality of life than sedentary women, and sedentary women has more improve on quality of life at the end of treatment, BS is a form of PA. Even so the literature that links inactivity with chronic LBP is extensive. Peña [26] in his review about the PA in arthrosis says that physical inactivity worsens the disability in most patients with articular diseases who adopt a sedentary lifestyle; he says also that a regular PA is necessary to keep the muscle strength, as well as the structure and function of articulations. In addition, he also remarks that the PA does neither hurt nor favour the progression of arthrosis, but improves the function, and has beneficial effects in different diseases as chronic LBP among others. In a recent prospective study of 517 patients with 6 years of monitoring, it is stated that physical inactivity is a risk factor for LBP [27].

Cochrane reviews and clinical guidelines support the effectiveness of making a controlled PA program on elders with chronic LBP to reduce the risk of disease [28-30]. In summary, the level of inactivity before the injury, affects the improvement of the pathology and pain. Thus, the patients of our study with high levels of PA, have an enhanced improvement on pain.

The relationship between BMI and pain perception has been studied by authors such as Cimolin et al [20], who speak about a correlation between obesity and the poor function of the spine secondary to the weakness and stiffness of the lumbar musculature, which is one of the main problems of chronic LBP and disability. In a systematic review of 56 articles about the frequency of a positive correlation between obesity and LBP it is found that 32% studies find statistically positive significance, the author of the review concludes that obesity should be considered as a possible risk indicator and not the cause of LBP [31]. Another prospective study conducted in 140 women divided in three different groups according to their BMI, to perform physiotherapy treatments for chronic LBP concludes that keeping the BMI inside a favourable range is beneficial to prevent this disease [32]. In our study, the frequency of obesity, overweight and normal weight in LBP patients were equilibrated, so we don’t find a elationship between obesity and more incidence of LBP, but we do it in the improvement of the perception of pain after the treatment. This fact could be attributed to the implementation of BS.

People with obesity have per se a bad feature of the spine, secondary to weakness and stiffness of the lumbar muscles, so, when these patients train the lumbar muscles during the performance of BS, they could receive an additional improvement in this regard.

CONCLUSIONS

In our study, the three treatment groups (BS, TENS and EM) of the intervention are homogenous, therefore, the patients selection and randomization were successful. TENS treatment combined with BS and treatment of EM combined with BS, and BS alone, with the intensity and dose used in the study, decreased significantly the perception of pain in women with chronic LBP after 20 sessions, and we find statistically significant differences in the decrease perception of pain and in the improvement of quality of life on BS group.

However, we didn’t find any study in the literature where these types of treatments are compared.

LIST OF ABBREVIATIONS LBP: Low Back Pain PA: Physical Activity BMI: Body Mass Index TENS: Transcutaneous Electrical Neurological Stimulation EM: Electromagnetic Therapy BS: Back School Hz: Hertz VAS: Visual Scale Analogue FS: Fast Sorter Physical Activity METS: Basal metabolic expenditure SD: Standard deviation

COMPETING INTERESTS The authors declare that they have no competing interests.

AUTHORS’ CONTRIBUTIONS

PE conceived of the study, selected and collected the participants, carried out the interventions and the acquisition of data, controlled and interpreted the data bases, performed the statistical analysis, designed and drafted the manuscript.

RM participated in the design of the study, interpreted the data bases, performed the statistical analysis, coordination and helped to draft the manuscript.

NR participated in the design of the study, in interprets of the data bases, in performance of the statistical analysis and helped to draft and to revise the manuscript.

GM participated in the design of the study, in interprets of the data bases, in performance of the statistical analysis and helped to draft and to revise the manuscript.

All the authors read and approved the final manuscript.

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