Investigation of Trunk Neuromuscular Control in Patients With Non-specific Low Back Pain
Condition: Low Back Pain
MeSH terms: Back Pain; Low Back Pain
Study type: Interventional

Summary: 
      The purposes of this study include 1) determine clinical utility of clinical observation of
      aberrant movement patterns during functional trunk and pelvic movements in asymptomatic
      individuals and patients with non-specific low back pain, 2) characterize trunk neuromuscular
      control in asymptomatic individuals and patients with non-specific low back pain, and 3)
      determine the appropriate physical therapy intervention that addresses trunk neuromuscular
      control deficits in patients with non-specific low back pain.
    

Detailed description: 
      This study will use a sample of convenience between the ages of 21 - 65. Patients with
      non-specific low back pain (NSLBP) will be recruited by advertisement in 2 Mahidol university
      physical therapy clinics and participating clinics and hospitals. Asymptomatic participants
      will be also recruited by flyers posted in 2 Mahidol university physical therapy clinics.

      Based upon power analysis for change in kinematic pattern in patients with NSLBP after an
      8-week core stabilization exercise program, a total required sample size is 29 patients with
      NSLBP to detect a medium effect size (Cohen's d) of .48 at level (α) of .05 and power (1-β)
      of .80. Fifteen percent drop-out rate is used as a conservative sample size calculation.
      Therefore, 34 patients with NSLBP (29 X 15% drop-out) and 34 age-, sex-, and BMI-matched
      asymptomatic participants will be included for each independent intervention study (core
      stabilization exercise approach, movement system impairment approach, neuromuscular
      activation using suspension, and kinematic linkage imbalance approach). Each intervention
      will be separately collected and analyzed. The total of 272 participants will be recruited to
      fulfill this study project (4 independent intervention studies). However, sample size for
      asymptomatic participants can be decreased if participant from one intervention study is
      matched with patients with NSLBP in other intervention studies.

      Patients with NSLBP who are interested in participation will undergo a screening process
      using inclusion-exclusion criteria checklist and receive brief information regarding the
      study. If they meet all inclusion criteria, the consent process and biomechanical testing
      will be scheduled. On date of consent and biomechanical testing, both asymptomatic
      participants and participants with NSLBP will be provided a consent form. To ensure they
      understand the study, they will be simply asked regarding the study (i.e. objectives,
      benefits, etc.) before signing the consent form. After the participants provide a written
      informed consent, they will undergo a standardized physical therapy examination performed by
      an experienced physical therapist (PT-A). For patients with NSLBP, they will also complete 3
      clinical outcome measures including 1) numeric pain rating scale (Thai version), 2) Oswestry
      disability index (Thai version), and 3) general health status questionnaire (Thai version).
      This pre-biomechanical data collection process will last approximately 60 minutes.

      For biomechanical testing, body landmarks will be identified and marked with a skin pen for 4
      motion sensors and 16 pairs of surface electromyography (EMG) electrodes in lower back and
      abdominal areas. Any hair in the area around the sensors and electrodes will be shaved.
      Before placing surface EMG electrodes, the skin will be lightly abraded using abrasive paper
      and cleaned using cotton with alcohol to lower the skin impedance. Electrodes will be aligned
      parallel to the muscle fibers. This process will take approximately 30 minutes. Then,
      participants will proceed to the biomechanical testing which includes 1) trunk muscle
      strength test, 2) functional trunk and pelvic movement tests, and 3) core control tasks.

      Trunk muscle strength test Strength test Participants will wear a climbing harness connecting
      with a tension load cell and sit in a testing apparatus in a neutral trunk position with
      pelvic securely locked. This apparatus intends to reduce compensation from lower extremities
      during sub-maximal (15% of body weight) and maximal voluntary isometric contractions.
      Participants will be instructed to use their trunk gradually pulling the load cell (isometric
      contraction in neutral trunk position) for 10 seconds in forward, backward, and 2 side
      bending directions. Participants will be given 2 practice trials in each direction to adjust
      the force and reduce a learning effect. Visual feedback of force to sub-maximal target will
      be provided. Two trials of sub-maximal voluntary isometric contractions will be collected in
      each direction. Only 1 trial of maximal voluntary isometric contraction will be collected to
      avoid muscle fatigue (in both asymptomatic participants and patients with NSLBP) and pain
      exacerbation (in patients with NSLBP). The intention of collecting maximal contraction data
      is to use for EMG standardization. Participants will rest in between each trial to minimize
      fatigue. Pain and rating perceived exertion (RPE) will be monitored and recorded at the end
      of trunk strength test. This protocol will take approximately 15 minutes.

      Functional trunk and pelvic movement tests Participants will stand on a drawing paper with
      feet shoulder width apart in front of the motion transmitter. The foot print will be drawn
      using a marker. This foot print will be used for post-test positioning. The participants will
      stand in a natural stance facing away from the transmitter with arms down by sides.
      Participants will be instructed to stand up straight and maintain that position for
      digitization. After the completion of digitization, participants will be instructed to
      perform functional movements including 1) active forward bend and return to upright position,
      2) right and left straight leg raise tests, 3) right and left hip abduction with knee flexion
      tests, 4) quadruped backward rock test, 5) prone with right and left knee flexion tests, 6)
      prone with right and left hip internal/external rotation tests, and 7) prone with right and
      left hip extension tests. Participants will perform 2 trials of 3 consecutive repetitions of
      each functional movement tests. Two physical therapists (PT-B and PT-C), who are blinded to
      the group membership, will simultaneously observe and independently rate aberrant movement
      patterns during biomechanical data collection. This protocol will take approximately 30
      minutes.

      Core control tasks Participants will sit on an unstable chair with feet supported. The chair
      is mounted on a half ball that makes the chair unstable and tilt. Participants will be
      instructed to balance the chair without tipping the chair in any direction. The participants
      will maintain upright seated balance with crossing both arms in front of their chest. The
      participants will have an opportunity to get familiar with the balance testing protocol prior
      to the data collection to minimize the learning effect. This core control tasks aim to
      investigate the performances that represent static and dynamic stabilities of the trunk. For
      static stability, the participants will perform 3 trials of 60-second seated balance tests
      with their eyes open, and 3 trials of 60-second seated balance tests with their eyes closed.
      The participants will be given a 1-minute rest period between trials to avoid muscle fatigue.
      For dynamic stability, the participants will be instructed to perform a dynamic stability
      using lumbar spine (without trunk leaning to tilt an unstable chair as far as they can) in 8
      different directions (forward, backward, right, left, right diagonal, and left diagonal). The
      participants will be given 1 practice trial to reduce possibility of learning effect, and 3
      real trials with 1-minute rest period between trials. Pain and RPE will be recorded at the
      completion of core control task. This protocol will take approximately 30 minutes.

      Patients with NSLBP will be assigned to one of different physical therapy interventions
      according to participating clinics and hospitals, while asymptomatic participants will be
      encouraged to maintain usual daily activities and avoid participating in activities that
      involve trunk muscle exercise. After completion of an 8-week physical therapy intervention,
      both asymptomatic participants and patients with NSLBP will undergo the standardized physical
      therapy examination and biomechanical data collection again. For patients with NSLBP, they
      will also complete clinical outcome measures for post physical therapy intervention.

      Physical therapy intervention Patients with NSLBP will be treated with a standard physical
      therapy intervention based upon different treatment concepts. In general, these interventions
      include strengthening exercise, endurance exercise, stretching exercise, patient education,
      patient ergonomics, and home exercise program. There is no reported adverse effect of those
      physical therapy interventions. Therefore, those physical therapy interventions are safe for
      treating patients with NSLBP. Each patient will be treated 1-2 times per week for 60 minutes
      each session for 8 weeks by experienced physical therapists. Patients will be given a home
      exercise log for exercise compliance.

      All Statistical analyses will be performed using statistical package for the social science
      (SPSS) software (IBM SPSS Statistics for Windows, Version 21.0., New York, USA).

      Study objective 1 is to determine inter-rater reliability and diagnostic accuracy of clinical
      observation of aberrant movement patterns during functional trunk and pelvic movements in
      patients with NSLBP. Agreement on the presence/absence of aberrant movement patterns between
      physical therapists (PT-B and PT-C) will be determined using separate kappa statistics.
      Diagnostic accuracy will be determined using accuracy statistics which include sensitivity,
      specificity, and likelihood ratio. Significance level will be held at .05 for all analysis.
      Confidence intervals will also be calculated.

      Study objective 2 is to characterize neuromuscular control in asymptomatic participants and
      patients with NSLBP during functional activities. Each variable will be analyzed separately.
      Descriptive statistics (i.e. mean and standard deviation) will be performed and statistical
      assumptions (i.e. normal distribution, homogeneity of variance, etc.) related to specific
      statistical tests will be performed. Statistical transformation will be performed if
      appropriate. Then, statistical test (i.e. independent t-test, Mann-Whitney U-test, etc.) that
      appropriate to the data will be performed to determine the difference between asymptomatic
      participants and patients with NSLBP. Significance level will be held at .05 for all
      analyses. Post-hoc power analysis will also be performed to determine statistical power and
      effect size.

      Study objective 3 is to determine the appropriate physical therapy intervention that
      addresses neuromuscular control deficits in patients with NSLBP. First, the effects of each
      physical therapy intervention on trunk neuromuscular control and clinical outcomes will be
      determined. Prior to utilization of statistical tests, descriptive statistics will be
      performed and statistical assumptions will be tested. Transformation will be performed if the
      data are not normally distributed. Appropriate statistical tests will be performed to
      determine the effects of each physical therapy intervention on neuromuscular control and
      clinical outcome. Significance level will be held at .05 for all analyses. Post-hoc power
      analysis will be performed. In addition, this study objective will determine the ability of
      physical therapy intervention on matched- and unmatched-intervention patients based upon each
      intervention criteria. Each patient with NSLBP will be classified based upon clinical
      criteria of each physical therapy intervention. Pre-post difference for matched and unmatched
      groups will be compared using appropriate statistical tests. Significance level will be held
      at .05 for all analyses. Post-hoc power analysis will also be performed.
    

Intervention name(s): Exercise intervention
Intervention type(s): Other
Intervention description(s): Physical therapist will provide exercise for patients with low back pain for 60 minutes per day, 2-3 days per week for the total of 8 weeks.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Low back pain; Neuromuscular control