Standing Trunk Extension and Spinal Height in Low Back Pain
Condition: Low Back Pain
MeSH terms: Back Pain; Low Back Pain
Study type: Interventional

Summary: 
      Background: Standing trunk extension postures have been used for many years as a mechanical
      approach to low back pain (LBP), sometimes directed by therapeutic intervention, sometimes
      subconsciously performed by patientsto relieve LBP. However, no study to date has
      investigated the effect of standing trunk extension postures on spinal height and clinical
      outcome measures.

      Objective: The purpose of this study will be to evaluate in subjects with LBP following a
      period of trunk loading, how spinal height and/or pain, symptoms' centralization, and
      function outcome measures respond to:(1) standing repetitive trunk extension posture; and (2)
      standing sustained trunk extension posture. Lumbar range of motion (ROM) achieved during
      these two trunk extension postures will be compared to spinal height and outcome measures.

      Methods:A pre-test, post-test comparison group design (randomized clinical trial) will be
      used to determine how spinal height changes in response to sustained and repetitive standing
      trunk extension after a period of spinal loading. The study will evaluate the effects of
      sustained and repetitive trunk extension in standing on spinal height, pain, symptoms'
      centralization and function.

      Statistical Analysis: A mixed ANOVA will be used to statistically identify significant
      interactions and main effects for spinal height, pain and functionoutcome measures. Post-hoc
      pairwise comparisons will be used to locate significant differences between the different
      conditions. Significance will be set at α = 0.05. The Kruskal-Wallis 1-factor ANOVA for
      difference scores will used to determine changes of intensity and location of symptoms
      following sustained versus repetitive standing trunk extension. Spearman Rank correlation
      will be used to evaluate the relationship between spinal height changes and changes of pain
      and location of symptoms for each group.
    

Detailed description: 
      Standing trunk extension postures have been used for many years as a mechanical approach to
      low back pain (LBP), sometimes directed by therapeutic intervention, sometimes subconsciously
      performed by patients to relieve LBP. However, no study to date has investigated the effects
      of standing extension postures on spinal height, pain, centralization and function.
      Therefore, the purposes of this study will be to evaluate in a sample of LBP patients the
      effect of standing trunk extension, both sustained and repetitive, following a period of
      spinal loading, on (1) spinal height; (2) pain; (3) symptoms centralization and (4)
      functional measures.

      Research Design(s) A pre-test, post-test comparison group design (randomized clinical trial)
      will be used to determine how spinal height changes in response to sustained and repetitive
      standing trunk extension after a period of spinal loading. The study will use a 2 (between
      subjects - type of trunk extension: sustained vs. repetitive) x 3 (within subjects - time:
      before vs. after vs. 2 weeks after) mixed design to evaluate the effects of sustained and
      repetitive trunk extension in standing on spinal height, pain, centralization and function
      outcome measures.

      Subjects / Specimens Systematic consecutive sampling of up to 100 subjects with LBP (40
      subjects completing both days of data collection) attending "Sports medicine and Physical
      therapy clinic" in Fredericksburg (Texas) as patients or for the purpose of health and
      wellness will be recruited. Flyers will also be posted at physician offices and the general
      Fredericksburg community and surrounding areas to inform subjects about the study.

      Testing Sequence Subjects will be asked to attend two physical therapy sessions over
      approximately a 60-minute period each to complete the study.

      SESSION 1

      Participants will complete a pre-screening questionnaire regarding inclusion. Each subject
      will watch an audio-visual power point presentation explaining the study, test procedures and
      describing the interventions (standing repetitive trunk extension and standing sustained
      trunk extension). Written informed consent will be obtained. To determine directional
      preference, the investigator (JH) will use the guidelines set forth in the directional
      preference definition and based off of standards set forth in randomized clinical trials.
      Directional preference has been defined as either (1) a specific direction of trunk movement
      or posture noted during the physical examination or (2) a specific easing factor reported by
      the patient during the subjective history that alleviates or decreases the patient's pain,
      with or without the pain having changed location and/or increased the patient's lumbar range
      of motion. A questionnaire including pertinent medical history will be completed. Subjects
      will complete (1) a Numerical Pain Rating Scale (NPRS) to rate their current, minimum,
      maximum and average LBP over the last two days as well as paresthesia signs/symptoms
      intensity; (2) Body Diagram for indicating location of symptoms; (3) Modified Oswestry low
      back pain questionnaire; (4) Fear Avoidance Belief Questionnaire. A researcher will record
      subject's height and weight.

      If the subject meets criteria for inclusion in the study, the subject will complete a
      familiarization procedure to determine the consistency to reposition themselves in the
      stadiometer. Subjects able to reposition themselves in the stadiometer with a SD of 1.3mm or
      less for five consecutive measurements will be included in the study. The digital display
      will be covered to blind the researcher performing the measurements. The data will be
      automatically recorded by the stadiometer and manually downloaded to a laptop computer.

      At the beginning of data collection, a randomization plan generator
      (http://www.randomization.com ) will assign each subject to one of two interventions: (1)
      standing repetitive trunk extension at a rate of 10 per 45 seconds, repeated five times with
      15-second rest breaks; or (2) standing sustained trunk extension for 5 x 45 seconds with
      15-second rest breaks. Each subject will complete one intervention. The intervention number
      assigned will be recorded by the subject next to their name to allow blinding of the
      investigator as to which intervention the subject is assigned to. The subject will undergo
      the test sequence after a 10-minute period of trunk unloading in a supine posture to ensure
      spinal height is normalized, head in neutral posture, knees supported over a small bolster
      pillow, hands placed on the abdomen. The subject will reposition on the stadiometer and
      spinal height will be measured after a relaxed exhalation. The subject then will undergo a
      five-minute period of loaded upright sitting with a 4.5kg bag secured on each shoulder and
      spinal height will be measured (Measurement 2). As continued spinal height reduction has been
      demonstrated following loaded sitting, the subject will undergo an additional five minutes
      sitting without load and spinal height will be measured (Measurement 3). Inclinometers will
      be used to take an initial measure of each subject trunk extension prior to intervention. The
      subject will then undergo one intervention for 5 minutes as previously described, according
      to the randomization assignment. In order to determine how sustained and repetitive
      interventions related in terms of change in spinal height, the time to perform the sustained
      lumbar posture matches the time necessary to perform the repetitive lumbar extension
      postures.

      The subject will reposition on the stadiometer and spinal height will be measured
      (Measurement 4). Trunk extension will be measured to determine the strength of correlations
      between the degree of trunk extension during standing trunk extension posture and spinal
      height, pain and centralization testing outcomes changes. The subject will score their low
      back and lower extremity symptoms using NPRS, and map their pain on a body pain diagram prior
      to intervention, immediately after and 2-week following the intervention to determine pain
      rating and centralization of symptoms. The principal investigator will apply a numeric
      overlay template to the patient's body diagrams to document the most distal pain location
      scores between 1 and 6. Higher score will indicate a more distal symptoms' location.

      Home instructions Subjects will be instructed to continue to use their medications, including
      medications aimed at decreasing their pain, as prescribed by their primary healthcare
      provider and not to change them during the follow-up two-week period. A sheet including home
      exercise instructions will be provided to each patient. Instructions will include repetitive
      or sustained trunk extension based on random group assignment, performed approximately 5
      times per day. Each subject will complete a sheet recording home exercise compliance upon
      arrival in session 2.

      SESSION 2

      Subjects will complete: (1) a NPRS to rate their current, minimum, maximum and average LBP
      over the last two days as well as paresthesia signs/symptoms intensity; (2) Body Diagram for
      indicating location of symptoms; (3) Modified Oswestry low back pain questionnaire; (4) Fear
      Avoidance Belief Questionnaire. Each subject will then complete a familiarization procedure
      to determine the consistency to reposition themselves in the stadiometer as described in
      session 1. The subject will undergo a 10-minute period of trunk unloading in a supine posture
      to ensure spinal height is normalized as described in session 1. The subject will reposition
      on the stadiometer and spinal height will be measured after a relaxed exhalation (Measurement
      1). The subject then will undergo a five-minute period of loaded upright sitting with a 4.5kg
      bag secured on each shoulder and spinal height will be measured. The subject will then
      undergo an additional five minutes sitting without load and spinal height will be measured
      (Measurement 3). Inclinometers will be used to take an initial measure of each subject trunk
      extension prior to intervention. The subject will then undergo the same intervention as in
      session 1 for 5 minutes as previously described (standing repetitive trunk extension or
      standing sustained trunk extension). The subject will reposition on the stadiometer and
      spinal height will be measured (Measurement 4). Trunk extension will be measured to determine
      the strength of correlations between the degree of trunk extension during standing trunk
      extension posture and spinal height, pain and centralization testing outcomes changes. The
      subjects will then score their low back and lower extremity symptoms using NPRS, and map
      their pain on a body pain diagram.

      Investigator Blinding Two investigators will be involved with data collection and will carry
      out inclinometer measurements of lumbar and sacral posture, supervised positioning in the
      stadiometer and stadiometric measurements. The measuring investigator will be blinded to the
      intervention (each subject will receive a hidden random number and will perform independently
      the intervention in a treatment room) and the stadiometric measurements during the
      experiment. He will also be responsible for assigning subjects to their initial groups,
      supervising the subjects' positioning in the different standing postures and confirming that
      a stadiometer reading is recorded on an Excel spreadsheet.

      Subjects Charges There will be no charge for the two physical therapy sessions, including
      examination and intervention. Following the two intervention sessions, subjects referred by
      primary care providers (physicians, chiropractors, nurse practitioners, physician assistants)
      to physical therapy for LBP will have the choice to receive standard care and be charged for
      physical therapy intervention.
    

Intervention name(s): Repetitive Trunk Extension; Sustained Trunk Extension
Intervention type(s): Other; Other
Intervention description(s): Subjects will be asked to perform standing repetitive trunk extension at a rate of 10 per 45 seconds (Figure 2), repeated five times with 15-second rest breaks.; Subjects will be asked to perform standing sustained trunk extension for 5 x 45 seconds with 15-second rest breaks.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Low Back Pain; Extension; Posture; Physical Therapy