Effect of Combined Brain and Back Muscle Stimulations on Level of Physical Disability among Chronic Low Back Pain Patients

 

Abdulkareem Umar¹*, Nordin Bin Simbak², Naresh Bhaskar Raj³, Aisha Ahmad⁴,

Shmaila Hanif⁴, Ashiru Hamza Muhammad⁴, Mahadeva Rao US⁵

¹Postgraduate Student, Universiti Sultan Zainal Abidin (UniSZA), 20400, Kuala Terengganu,

Terengganu Darul Iman Malaysia.

²Dean, Faculty of Medicine, Universiti Sultan Zainal Abidin (UniSZA), 20400, Kuala Terengganu,

Terengganu Darul Iman Malaysia.

³Lecturer, Faculty of Health Sciences, Universiti Sultan Zainal Abidin (UniSZA), 21300,

Kuala Terengganu, Terengganu Darul Iman Malaysia.

⁴Lecturer, Department of Physiotherapy, Faculty of Allied Health Science, Bayero University Kano, Nigeria.

⁵Professor, Faculty of Medicine, Universiti Sultan Zainal Abidin (UniSZA), 20400, Kuala Terengganu, Terengganu Darul Iman Malaysia.

 

ABSTRACT:

The purpose of this study is to determine the effect of combining anodal cortical and back muscle stimulations in chronic low back pain (CLBP). Forty eight patients divided into four groups participated in the study. The control group received infrared therapy (IRT) and a session soft tissue massage (STM), while those in the other groups received combined dorsolateral prefrontal cortex (DLPFC) and Back muscle stimulation plus IRT and STM, combine primary motor cortex (PMC) and Back muscle stimulations plus IRT and STM and Williams flexion exercise plus IRT and STM respectively. The primary outcome (disability level) was assessed using modified Oswestry low back pain disability questionnaire while bothersome questionnaire (secondary outcome) was used to assess the level of bothersome of the participants. Statistical analysis revealed that participants that received DLPFC/Back muscle stimulation plus IRT and STM (p=0. 046, z=-2.02) have much improvement in disability compare to those that received PMC /Back muscle stimulations plus IRT and STM. In addition, the control intervention (IRT and STM) proves to be more effective (P=0.025, Z=-2.24) compare to other groups. It is concluded that IRT and a session of STM is more effective in the reduction of disability and improvement of the functions in CLBP than the combine stimulations, but the result cannot be generalized because of the small sample size and type of design used in this clinical trial.

 

 

INTRODUCTION:

Chronic low back pain (CLBP) is a widespread and costly problem, which leads to a major cause of medical expenses, absenteeism and disability in developed nations ^1,2. The average one year prevalence and lifetime prevalence of 33% and 50%, nonspecific CLBP among adolescents in Africa was reported when compared with 36% and 62% one year prevalence and lifetime prevalence among adults Africans respectively ³.

Three basic neuroplastic changes, including structural, functional and neurochemical features, which contributes to the development of chronic pain state, were revealed in the brain of CLBP survivors from neuroimaging studies³. Moreover, several regions of the brain of CLBP survivor including the left dorsolateral prefrontal cortex (DLPFC), left somatosensory cortex , and right anterior cingulated cortex, shows various alteration suggesting a potential cause of the chronic pain state³. A successful treatment of CLBP was associated with increased cortical thickness notably in left DLPFC³. Thus, suggesting that structural changes in chronic pain are at least partially reversible in some of the brain region. The management of CLBP involves various conservative techniques, in addition to the drugs which are mostly associated with some adverse effect. Noninvasive stimulation is used as one of the conservative techniques in the rehabilitation of CLBP, the technique involves the stimulation of peripheral painful tissue or the use of magnetic and electrical potential in stimulating the brain neuromatrix area^3,4. Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (TDCS) are the important noninvasive brain technique used to reduce pain and disability by altering the activity of brain neurons specific to the site of application and the parameters used^4,5. It was revealed from a systematic review of chronic pain that anodal TDCS had a pain reducing effect in patients with chronic pelvic pain, fibromalgia, spinal cord injury, CLBP and various chronic conditions^5,6. TDCS has advantages over other noninvasive brain stimulation technique of being cost effective, pain free and safety. The sham treatment was indistinguishable from the active treatment during implementation⁷. Likewise, it modulates neural activities in the stimulated and interconnected regions compared with TMS, which generate a magnetic field that was associated with some adverse effect such as fainting, seizure, transient hearing loss and discomfort ⁵.

 

Transcutaneous electrical nerve stimulation (TENS) is a form of peripheral noninvasive therapy that is used in a variety of painful conditions⁸. TENS machine is capable of being self-administered, cost effective and stimulate the excitable tissues via skin surface electrodes at well-tolerated intensities^9,10,11. Study of the combined effects of brain and back muscle stimulations in chronic low back pain was scarce, based on the current literature of the present study. Moreover, of the few studies that were available no comparison was made between the different cortical regions. Therefore, this study aims to determine the effects of combining TDCS and back muscle stimulations on two different brain matrix in patient with non specific chronic low back pain.

 

 

MATERIALS AND METHODS:

Participants:

The sample size was computed using G- power software with α = 0.05 (5% chance of type I error) and 80% power respectively. This provided the sample size of 53, in which 5 of the patients were excluded as result of being part of an ongoing research study related CLBP. The subjects have to meet the following criteria: age between 18-65 years, complaining of back pain for more than three months with baseline rating of 4 on VAS and Seeking care for low back pain, while those with an evidence of specific spinal pathology (fracture, neoplasm, deformity and spinal infections), history of spinal surgery, known neurological disease, used of pacemaker or metallic implant, identifiable psychotic illness or other mental illness, pregnancy, involvement in any other ongoing research project relating to low back pain were excluded from the study. The framework of the study is summarized below:

 

 

The study was carried out at Sir Muhammad Sunusi Specialist Hospital Kano, Nigeria; after the ethical clearance for the conduct of the study was received from Universiti Sultan Zainal Abidin Research Ethics Committee. A purposive sample technique was used to recruit and assigned the patients into one of the four groups: PMCS/TENS plus IRT and RSTM (n=12), DLPFCS/TENS plus IRT and RSTM (n=12), Williams’s flexion exercise plus IRT and RSTM (n=12) and control (n=12). The study protocol was fully explained to all the participants, and a written consent form was signed after having understood the study. All the participants were assessed 3-days pre-intervention, followed by four-week intervention period and 3-days follow-up period for the post intervention assessment. The research was a pretest-posttest experimental design in which a set of intervention of combined brain and back muscle stimulation with conventional therapy of infra red therapy and soft tissue massage were prescribed to all the participants

 

ASSESSMENT QUESTIONNAIRES:

Primary outcome parameter:

Modified oswestry low back pain disability questionnaire was used to assess the patients physical disability level. This questionnaire has been designed to provide information on how back pain affects people ability to manage activity of daily living. The assessment was performed 3 days pre intervention and post intervention respectively. Some of the participants were unmarried and had no sexual relationship; therefore the section 8 of the questionnaire was not applicable to them. The score were calculated using the formula below:

 

Level of disability = Total scores / 45 (total possible scores) × 100

 

The measurement characteristics of the modified oswestry low back pain disability questionnaire are good to excellent with test-retest ICC of 0.83-0.94 one to fourteen days ¹²

 

Secondary outcome parameter:

A global score of “bothersomeness” was used as the secondary outcome measure. This is a single question ("how bothersome is your pain today?”) tool which is measure on a 5 point likert scale of “not at all”, “slightly”, “moderately”, “very much” and “extremely” bothered ¹³

 

Stimulation:

The position and electro montage of PMC and DLPFC was located using International 10-20% EEG system (fig. 1 below) ¹⁴. The anodal arm of the TDCS machine was used as the active electrode while the cathodal arm was used as the reference electrode.

 

Fig 1: Position of PMC and DLPFC for Electrode Montage¹⁴

COMBINED PMC AND BACK MUSCLE STIMULATION GROUP:

Patients assumed supine position. The anode electrode was placed over the primary motor cortex of the patients, that is at a point 1 cm anterior and 4 cm lateral to the cortical vertex, which correspond to C3/C4 in EEG system¹⁴, to complete the circuit the cathode electrode was attached over the contralateral supraorbital region. All the electrodes were secured with soft elastic straps. Subjects whose pain are predominantly on one side of their back, the contralateral hemisphere was used to stimulate the primary motor cortex, while for those whose pain is dispersed, the hemisphere contralateral to the subjects self-nominated dominant hand was used. This is inconsistent with previous clinical studies^15,16. In addition, high frequency and low intensity TENS electrode was placed at the painful site of the paravetebral muscle and both the stimulations lasted for 13 min. The patients also received additional 15 min of infrared therapy and a session of soft tissue massage (STM) after the stimulations.

 

COMBINED DLPFC AND BACK MUSCLE STIMULATION GROUP:

The subjects in this group also assumed supine position, while the anode electrode was placed in the left cerebral cortex, which correspond to F3 region in 10/20 EEG system. The TENS electrode was also applied at the painful site of the back muscle couple with 15min of IRT followed by a session of STM after the stimulation.

 

CONTROL GROUPS:

These include conventional physiotherapy group that received 15 minute of IRT and RSTM and the William flexion exercise group that received six sets of lumber flexion stabilization exercise and 15 minute of IRT and RSTM respectively. The duration of the treatment received by each group was twice a week for a period of four weeks.

 

STATISTICAL ANALYSIS:

Wilcoxan signed rank test was used to determine the within group statistical median difference of the intervention. Statistical Package for the Social Sciences (SPSS) version 20.0 at p-value 0.05 was used for the analysis.

 

RESULTS AND DISCUSSION:

This study recruited a total of forty eight participants with chronic low back pain, out of which 12 participants were allocated to four different Interventional groups. Findings from table 1 and 2 below revealed a statistical significant median difference of disability and bothersome index in the group that received combined DLPFC and back muscle stimulation and control (IRT and STM alone).

Table 1: Effectiveness of the Studied Interventions

Variables	Median (IQR)
	Pre-test	Post-test	Z- starta	P- value
Disability
Williams flexion exercise plus IRT & STM	26(0.5)	23(3)	-1.34	0.180
PMC/Back muscle stimulation plus IRT & STM	20(14.5)	16.5(10)	-1.00	0.317
DLPFC/Back muscle stimulation plus IRT & STM	21(10.5)	18(7)	-2.02	0.046
Control	29(15.5)	20(16.5)	-2.24	0.025

A Wilcoxon signed rank test, IqR= interquatile range, PMC= primary motor cortex, DLPFC= Dorsolateral prefrontal cortex, IRT= infrared therapy, STM= soft tissue massage

 

Table 2: Effectiveness of the Studied Interventions

Variables	Median (IQR)
	Pre-test	Post-test	Z- starta	P- value
Bothersome
Williams flexion exercise plus IRT & STM	3.5(2)	2(1)	-0.97	0.331
PMC/Back muscle stimulation plus IRT & STM	2.5(1)	2(1)	-1.00	0.317
DLPFC/Back muscle stimulation plus IRT & STM	2.5(1)	2(2)	-2.11	0.035
Control	3.5(2)	3(2)	-2.11	0.035

A Wilcoxon signed rank test, IqR= interquatile range, PMC= primary motor cortex, DLPFC= Dorsolateral prefrontal cortex, IRT= infrared therapy, STM= soft tissue massage

 

The sample size was similar to the study conducted by ⁵, on an ameliorating effect of transcranial direct current stimulation in chronic low back pain. On the other hand, it was in contrast with the study conducted by ¹, on the effect of TDCS in nonspecific chronic low back pain, in which a small sample size of eight participants was used in the study. Statistical significant median difference of disability index was seen in the DLPFC/Back muscle stimulation plus IRT and STM (P=0.046, Z=-2.02) and the control (P=0.025,Z=-2.24) compare to other groups. This was in contrast with the study conducted by ¹⁷, in which significant reduction was seen among the patients that received PMC/Back muscle stimulation. This could be due to variation in the sample size and the design used in both the study. Moreover, significant reduction of the level bothersome at (p=0.035, z=-2.11) was revealed among the participants in the control (IRT and STM) and combined DLPFC and back muscle stimulation.

 

CONCLUSION:

The outcome of this study revealed the impact of combined brain and peripheral stimulation in the management of CLBP. Due, the control intervention (IRT and STM) proves to be more effective when compared with the combined stimulation groups which could be attributed to the small sample sized and the methodology used. Therefore, the result cannot be generalized because of a fore mention limitations. There is need for further study with large sample size, randomized control design and longer follow up period which could provide a clearer picture of the impact of differential noninvasive combined brain and back muscle stimulation in the management of CLBP.

 

 

 

ACKNOWLEDGMENT:

Alhamdulillah, I wish to thank the Kano State Government of Nigeria for the courage and support received in the smooth conduct of this paper. Also to my able supervisor Professor Dr Nordin Bin Simbak, Dean, Faculty of Medicine Universiti Sultan Zainal Abidin, Kuala Terengganu, Malaysia for his kindly advice and support for the smooth conduct of my research.

 

ETHICAL ASPECTS:

The study has been approved by the ethics committee of the Kano State Hospital Management Board, Nigeria. Ethical approval to start the study was provided by the university ethics committee of Universiti Sultan Zainal Abidin, Malaysia.

 

CONFLICTS OF INTERESTS:

All authors have none to declare.

 

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Accepted on 15.10.2017        © RJPT All right reserved

Research J. Pharm. and Tech 2017; 10(10):3326-3330.