Clinical Examination Procedures to Determine the

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Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at Washington University School Medical Lib on September 8, 2014. For personal use only. No other uses without permission. Copyright © 2012 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.

GREGORY HOLTZMAN, PT, DPT1 • MARCIE HARRIS-HAYES, PT, DPT1 • SHANNON L. HOFFMAN, PT, DPT2 DEQUAN ZOU, DSc3 • REBECCA A. EDGEWORTH, PT, DPT4 • LINDA R. VAN DILLEN, PT, PhD5

Clinical Examination Procedures to Determine the Effect of Axial Decompression on Low Back Pain Symptoms in People With Chronic Low Back Pain

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standardized clinical examination based on system impairment (MSI) model has been validated for the assessment of people with (LBP).28,35,36 The examination includes tests

TTSTUDY DESIGN: Observational.

the movement developed and low back pain of movements

immediate or complete improvement in symptoms when the direction of lumbar motion or alignment is corrected according to principles of the movement system impairment (MSI) model. Axial compression of the spine may be responsible for the remaining symptoms.

(100%) and 16 of 20 (80%) subjects, respectively, reported an improvement. When traction was applied to subjects in right and left sidelying, 6 of 11 (55%) and 7 of 9 (78%), respectively, reported an improvement. When patients performed a push-up in sitting, 36 of 51 (71%) reported an improvement. In subjects who had symptoms in unsupported sitting, 41 of 57 (72%) reported an improvement in supported sitting. In subjects who reported symptoms in standing, 33 of 47 (70%) reported an improvement in hook-lying.

41.9  11.5 years; 38 females, 32 males) with chronic LBP were evaluated using a standardized MSI exam. Seven tests assessing the effects of spinal decompression on LBP were added to the exam if the subjects’ symptoms were not alleviated with typical standardized corrections of movement and alignment. For each test of decompression, subjects reported their symptoms compared to a reference movement or position.

sistently reported an improvement in symptoms with tests proposed to decrease the axial load on the spine. These tests are a quick and effective way to assess the contribution of axial decompression to LBP symptoms and potentially could be used as part of the plan of care. J Orthop Sports Phys Ther 2012;42(2):105-113, Epub 25 October 2011. doi:10.2519/jospt.2012.3724

TTOBJECTIVE: To assess the effects of spinal

decompression procedures performed during a clinical exam on low back pain (LBP) symptoms.

TTBACKGROUND: Not all patients report an

TTMETHODS: Seventy subjects (mean  SD age,

TTRESULTS: When decompression was performed during lateral bending to the right and left, 21 of 21

TTCONCLUSION: Patients with chronic LBP con-

TTKEY WORDS: axial loading, distraction, lumbar spine, traction

and positions in which judgments of lumbar movement and alignment are made and symptoms are assessed. For movements or positions that reproduce LBP symptoms, the test is repeated with a standardized manual correction of lumbar motion or alignment (ie, to limit the particular direction of lumbar motion observed with a test or to position the patient in a neutral alignment) and symptom behavior is reassessed. Based on the results obtained from the tests and the specific corrective measures applied, clinicians can classify patients with LBP into 1 of 5 subgroups, named for the directions of lumbar movement and alignment (flexion, extension, or rotation) that appear to contribute to the LBP problem. In previous reports, up to 95% of patients improved with 1 or more of the typical, standardized corrections of movement and alignment used in the MSI clinical examination discussed above34,36; however, there were some patients who did not fully improve. Specifically, patients continued to complain of LBP symptoms with some tests even when the direction of their lumbar motion or align-

Assistant Professor, Program in Physical Therapy, Department of Orthopedic Surgery, Washington University School of Medicine, St Louis, MO. 2Research Physical Therapist, Program in Physical Therapy, Washington University School of Medicine, St Louis, MO. 3Associate Professor, Program in Physical Therapy, Department of Radiology, Washington University School of Medicine, St Louis, MO. 4Instructor, School of Physical Therapy & Rehabilitation Sciences, University of South Florida, Tampa, FL. 5Associate Professor, Program in Physical Therapy, Department of Orthopedic Surgery, Washington University School of Medicine, St Louis, MO. This work was supported by grant 5-R01 HD047709 from the National Center for Medical Rehabilitation Research, National Institute of Child Health and Human Development. The protocol used for the current study was approved by the Human Research Protection Office at Washington University in St Louis. Address correspondence to Dr Linda Van Dillen, 4444 Forest Park Blvd, Box 8502, Program in Physical Therapy, Washington University School of Medicine, St Louis, MO 63108. E-mail: [email protected] 1

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[ ment was corrected. In such cases, there may be another contribution to tissue loading that is not specifically addressed with the typical, standardized corrective measures. In particular, we propose that an important variable potentially contributing to continued symptoms with testing is axial compression. Axial compression of the lumbar region is operationally defined as loading applied parallel to the long axis of the spine, such that the tissues are approximated.25 There is evidence to suggest that a prolonged, upright posture in both sitting and standing is associated with a decrease in intervertebral disc height.2,12,13,15,21,32,33 Researchers propose that the weight of the trunk in an upright posture increases the axial load on the spine and compresses the intervertebral discs, thereby reducing the overall height of the affected discs. Thus axial compression of the lumbar spine may increase the mechanical stress on the intervertebral discs and thereby affect several other structures of the lumbar region. The weight of the trunk is not the only factor that may contribute to axial compression of the lumbar spine. Active contraction of the paraspinal muscles may increase the compressive load on the lumbar spine. Paraspinal muscle activation in static, low-load positions after completion of a loading task may contribute to poor recovery of stature, which is associated with changes in intervertebral disc height.7-9,27 Furthermore, increased paraspinal muscle activation during prolonged, unsupported sitting, in the absence of any exposure to an external load, may result in increased lumbar joint compression.3 Active contraction of the abdominal musculature also may increase the compressive load on the lumbar spine.1,17,22 Regardless of the specific mechanism, the cumulative effects of axial compression eventually may lead to LBP, due to increased mechanical stress on multiple structures of the lumbar region.1,16,20 Several strategies may be used to decrease axial compression of the lumbar spine. Researchers have noted an

research report TABLE 1

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Subject Characteristics*

Variable

Value

Age, y

41.9  11.5

Current pain intensity†

3.0  1.8

Weight, kg

73.8  13.5

Height, cm

169.5  10.4

Body mass index, kg/m2

25.5  3.0

Modified Oswestry‡

21.0  8.5

*Values are mean  SD (n = 70). † 11-point verbal numeric pain rating scale (0-10) in which 0 represents no pain and 10 represents worst imaginable pain. ‡ Modified Oswestry Disability Index Score. Measure of functional disability for people with low back pain, scored from 0% to 100%, with 0% representing no disability and 100% representing maximum disability.

increase in intervertebral disc height in the normal lumbar spine while in a recumbent, unloaded position.8,32 This suggests that a change in position from unsupported sitting to lying supine with the hips and knees flexed (ie, hook-lying) may reduce axial compression. Another mechanism by which axial compression may be decreased in an unloaded position is the relaxation of the paraspinal and abdominal musculature.8 Therefore, another strategy to reduce the compressive forces associated with a loaded position may be to facilitate relaxation of the paraspinal and abdominal muscles in that position. For example, the increased load associated with unsupported sitting may be reduced by using the backrest of a chair or manual support. We have developed procedures for a subset of tests in the standardized MSI examination to help the clinician quickly and easily determine whether axial decompression affects a patient’s LBP symptoms. These procedures are performed when patients’ symptoms do not fully resolve with the typical, standardized corrections performed during the MSI examination. For each test, specific procedures are used to reduce axial compression, and the effect of the reduction on symptoms is assessed. One set of tests, operationally defined as active tests of decompression, requires either the clinician or the patient to apply an external force

to unload the spine. A second subset of tests, operationally defined as transitional tests of decompression, requires the subject to change from one position, associated with an axial compressive load on the lumbar spine, to another, less loaded position. The decrease in the axial load during both the active and transitional tests of decompression could contribute to a decrease in LBP symptoms. The primary purpose of the present study was to assess the effect on symptoms of the active and transitional tests of decompression, which are presumed to decrease axial compression on the lumbar region in patients with chronic LBP. We hypothesized that the majority of tests would result in an improvement in symptoms for the majority of patients whose symptoms did not resolve with the typical, standardized corrections of movement and alignment.

METHODS Subjects

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convenience sample of 70 subjects (38 females and 32 males) with chronic LBP, who were consecutively enrolled in a randomized clinical trial comparing 2 nonsurgical interventions, was used for these analyses. This sample included all enrolled subjects in the clinical trial whose data were available at the time of these analyses.

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ria. Magnified symptom behavior was identified by the standardized physical examination items described by Waddell et al38 and included in our examination. Informed consent was obtained prior to participation in the study, and the rights of the subjects were protected. The protocol used for the current study was approved by the Human Research Protection Office at Washington University in St. Louis.

Procedures

FIGURE 1. Active test for decompression with lateral trunk flexion. Trunk lateral bending is performed from the patient-preferred standing position (A). Trunk lateral bending is repeated while the therapist applies a superiorly directed force to the patient’s trunk, with the intent to decrease compression on the lumbar spine (B).

TABLE 1 provides subject characteristics

for the current study population. Inclusion and exclusion criteria for the current study were identical to those of the clinical trial and are listed below. Subjects were recruited from outpatient physician and physical therapy clinics, as well as from the community of the St. Louis metropolitan area. All subjects required a physician’s referral to participate in the study. The inclusion criteria for participation in the study included the following: (1) chronic LBP for a minimum of 12 months37; (2) LBP symptoms, but not in an acute flare-up37; (3) 18 to 60 years of age; (4) able to stand and walk unassisted; (5) able to understand verbal and written English; and (6) able to read, understand, and sign a consent form. Subjects were excluded from the study if they were diagnosed by a physician with any of the following medical diagnoses, verbally reported any of the following conditions, or demonstrated any of the following symptoms during the standardized clini-

cal examination: (1) a structural spinal deformity such as stenosis, kyphosis, or scoliosis; (2) spinal fracture or dislocation; (3) disc herniation; (4) rheumatoid arthritis; (5) ankylosing spondylitis; (6) osteoporosis; (7) spinal complications such as a tumor or an infection; (8) a history of previous spinal surgery; (9) neurological loss; (10) pain or paresthesia below the knee; (11) etiology of LBP other than the lumbar spine; (12) history of neurological disease that required hospitalization; (13) ongoing treatment of cancer; (14) history of unresolved cancer; (15) magnified symptom behavior38; (16) pregnancy; (17) workers’ compensation or disability case; (18) litigation for the LBP problem; and (19) referral from a specialized pain clinic. Imaging studies were not required to confirm specific exclusion criteria. The diagnosis provided by the physician, and a standardized battery of self-report, screening, and clinical examination tests were used to identify people with any of the exclusion crite-

Prior to randomization into 1 of 2 nonsurgical treatment arms, each subject was evaluated by 1 of 2 trained physical therapists using a standardized examination, based on the MSI model, to classify people with LBP.28,35 The interrater reliability of the test items used in the standardized MSI examination, as well as the reliability of examiners to classify a subject’s LBP problem based on the test item responses, has been demonstrated in previous studies. Van Dillen et al35 reported agreement of 98% to 100% (kappa = 0.87 to 1.00) for the assessment of symptoms with test items and agreement of 65% to 100% (kappa = 0.00 to 0.78) for judgments of impairments related to movement and alignment with test items. Overall agreement for the assignment of an LBP classification based on findings from the test items has ranged from 75% to 83% (kappa = 0.57 to 0.75).5,23,30 During the examination, symptoms were assessed during several test movements and positions. If subjects experienced increased symptoms with a movement or position, a standardized correction of the direction of lumbar motion observed (eg, flexion, extension, or rotation) was applied manually and symptoms were reassessed. Throughout the examination, when subjects’ symptoms did not fully resolve with the typical standardized corrections of movement and alignment, procedures to assess the effect of decompression on the subject’s LBP were also performed. Two types of tests were used to assess the effect of decompression on each subject’s LBP: active and transition-

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FIGURE 3. Active test for decompression in sitting. While sitting in a chair, the subject is asked to place both hands on the armrests of the chair, cross the legs with the knees extended, and push into the armrests with the upper extremities without flexing or extending the spine, with the intent to decrease the axial compression on the lumbar spine.

FIGURE 2. Active test for decompression in sidelying. The subject assumes a sidelying position with the cervical region in a neutral position and the upper extremities and lower extremities positioned naturally (A). After correcting for lumbar flexion, extension, rotation, and/or lateral bending, a decompression force is applied through the pelvis in an inferior direction with the intent to decrease compression on the lumbar spine (B).

al tests of decompression.

Active Tests of Decompression The application of an external force was used to decompress the lumbar spine for 3 standardized active tests of decompression, each of which are specifically described in the following paragraphs. The immediate effects of these specific decompression procedures on subjects’ symptoms were recorded. Subjects reported whether symptoms were the same, increased, decreased, or eliminated with each test of decompression compared to a reference movement or position. For all tests, a decrease in or elimination of symptoms was considered an improvement. For the trunk lateral flexion in standing test, decompression was provided by the examining therapist, while the subject performed the movement. In standing, if a subject reported symptoms with

the test of trunk lateral flexion, then the therapist first attempted the typical, standardized modification to (1) facilitate more lateral bending in the thoracic region, (2) promote lateral bending evenly across all lumbar region joints, and (3) eliminate lumbar shift when the patient performed the test movement. However, if a subject’s symptoms did not fully resolve with this standardized modification, then a decompression force was applied by the therapist to the lumbar region in a superior direction while the subject repeated the lateral trunk movement (FIGURE 1). It should be noted that, because the subject is laterally flexing the trunk, the decompression force, though applied bilaterally by the physical therapist, may unload one side more than the other. For the sidelying test, an axial decompression force was provided by the therapist in an inferior direction during a static

position. If a subject reported symptoms in sidelying that were not fully resolved with the typical, standardized modifications to attain neutral spinal alignment, then the therapist could apply a decompression force in an inferior direction through the pelvis and assess the effect of this procedure on symptoms (FIGURE 2). Subjects who reported symptoms in standing performed the push-up test in sitting, for which the patient provided the decompression force. Subjects were instructed to sit in a chair with their legs crossed at the ankles and extended in front of them, resting on the floor. Keeping their torso and legs relaxed, they were instructed to push up on the arm rests of the chair (FIGURE 3). Verbal and tactile cues were provided to the patient, as needed to ensure correct performance and appropriate relaxation of the torso and legs. Subjects reported any change in symptoms relative to symptoms in standing.

Transitional Tests of Decompression LBP symptoms were also assessed for transition from one position associated with increased axial loading to another, less loaded position. For each of these transitions, subjects reported the im-

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in the sample had the same response. For left sidelying, the sample size was too small for the requirement of an expected cell count of 5 or more to be met. Therefore, chi-square analyses could not be performed for these 2 clinical tests.

Active Tests of Decompression

FIGURE 4. Transitional test for decompression of supported sitting. The subject is sitting upright with feet supported and thighs parallel to the support surface. The therapist places both hands bilaterally along the paraspinals of the lumbar region and the subject is instructed to relax the lower back into the therapist’s hands. The therapist passively supports the lower back and determines if the subject can relax the paraspinal muscles.

mediate effect of the less loaded position on their symptoms (same, increased, decreased, or eliminated) compared to the more loaded position. For all tests, a decrease in or elimination of symptoms was considered an improvement. Specific transitions tested included unsupported neutral sitting to neutral sitting with external support provided by the examining physical therapist (FIGURE 4) and standing to supine with hips and knees flexed (hook-lying) (FIGURE 5).

Data Analyses Descriptive statistics were calculated for select subject characteristics (TABLE 1). To examine the effect on symptoms of the active and transitional tests of decompression, frequency counts and percentages of symptom responses were calculated for each individual test. A chi-square test for goodness of fit was performed when sufficient sample sizes and variability in responses were present to meet the requirements of the test. To examine whether there were differences among subjects who required different numbers of decompression tests, subjects were categorized according to the number of decompression tests performed (0, 1 to 2, or 3 or more). For each

FIGURE 5. Transitional test for decompression in hook-lying. The subject is instructed to lie supine with hips and knees bent, so that the feet are flat on the support surface. If necessary, Dycem is used to prevent the feet from sliding on the support surface, allowing for optimal muscle relaxation.

subject receiving at least 1 decompression test, the percentage of tests with improved symptoms was first determined. Then the mean percentage across all subjects in each category was calculated (TABLE 2). An independent-samples t test was performed to determine whether there were differences in the percentages of tests with improved symptoms between the group who received 1 or 2 decompression tests and the group who received 3 or more decompression tests. To examine whether any other variables differed between groups based on the number of decompression tests received, a 1-way analysis of variance was conducted on age, body mass index (BMI), Oswestry Disability Index scores, and current pain intensity scores, and a chi-square test for independence was performed on gender. Finally, to examine whether (1) there were pairs of tests more likely associated with increased symptoms and (2) subjects responded better to specific pairs of tests, frequency counts and percentages of symptom responses also were calculated for all possible pairs of tests (TABLE 3). All statistical analyses were performed in SPSS Version 17 for Windows.

RESULTS

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requency counts and percentages of symptom responses are presented for all tests. Chi-square results are presented for all tests, except right trunk lateral flexion and left sidelying. For right trunk lateral flexion, all subjects

After the initial standardized corrections, 21 and 20 subjects continued to report symptoms with right and left trunk lateral flexion, respectively. When a decompression force was added during lateral trunk flexion correction to the right, all 21 subjects (100%) reported an improvement in symptoms; during lateral trunk flexion to the left, 16 of 20 subjects (80%, χ2 = 7.20, P