Abstract
Context:
The effectiveness of osteopathic manipulative treatment (OMT) on the lumbar spine has been studied qualitatively, but quantitative measurement of the effects of OMT has not been thoroughly investigated.
Objective:
To quantitatively measure the palpated improvements of OMT on the lumbar spine using ultrasonography (US) and correlate palpatory diagnosis with US measurements of lumbar asymmetry.
Methods:
From September to November 2018, we recruited 20 adult participants 18 years of age or older. Lumbar somatic dysfunction (SD) was identified via osteopathic palpation. US was then performed on all participants with standard machine settings (frequency, 7 MHz; depth, 7 cm; dynamic range, 60; tissue harmonic imaging; and single-image focus). Longitudinal images of each lumbar transverse process were recorded and saved bilaterally by an experienced radiologist and a medical student. The participant's SD was then managed using OMT, including Still technique, myofascial release, muscle energy technique, high-velocity low-amplitude technique, functional positional release, balanced ligamentous tension, and counterstrain. Following OMT, US was performed again in the same method. Measurements of the saved US images were reviewed using a Digital Imaging and Communications in Medicine viewer. These measurements were obtained by 3 separate observers (J.W., A.K., S.M.), using the same computer software. Statistical analysis included a 2-tailed paired t-test to analyze rotational asymmetry pre- and posttreatment, an intraclass correlation coefficient (ICC) to test intra- and interobserver reliability, and a Pearson correlation coefficient (PCC) to analyze the correlation between US findings and OMT.
Results:
The difference in soft tissue thickness before and after OMT was significant (P=.014), indicating improvements in rotational asymmetry. Side-bending asymmetry did not demonstrate statistically significant improvement. US findings correlated with the physician's palpatory rotational diagnosis (PCC=0.62, P=.004). ICC was greater than 0.9 for intra- and interobserver reliability tests of both US operation and offline image processing.
Conclusion:
The results of this study demonstrate that US is a feasible method of evaluating the efficacy of OMT. These results show good intra- and interobserver reliability of US acquisition and landmark measurement. Our study suggests that US assessment correlated closely with palpatory diagnosis. Our results also suggest that OMT can significantly improve lumbar rotational asymmetry, but did not improve side-bending asymmetry.
Low back pain (LBP) is a common problem that affects an increasing number of people globally.
1 LBP management is challenging for several reasons, including varying origins, variable patient pain threshold, and chronic nature. Evaluating the effectiveness of management approaches can be even more difficult because of a lack of quantitative measures.
Compared with pharmaceutical management and invasive procedures, osteopathic manipulative treatment (OMT) is considered both cost-efficient and effective.
2-4 Typically, the patient's perception of pain and palpatory examination are tools used to diagnose, treat, and measure improvement when using OMT. Pain is a functional parameter to determine the efficacy of a treatment clinically; however, it is less helpful when determining how the treatment caused improvement in the patient's symptoms. Pain is a subjective assessment that depends on a variety of uncontrolled variables. Furthermore, a self-reported perception of pain rated from 1 to 10 is an inconsistent predictor of good clinical outcomes.
5 With a lack of consistent pain measurement, it can be difficult for osteopathic physicians to consistently and accurately correlate bony landmarks with a clinically significant diagnosis and OMT.
6-8
Other parameters may provide more consistent results when evaluating OMT. For example, several studies
9-12 have evaluated the effectiveness of OMT using certain cytokines, pain tolerance, and muscle activation as indicators. Using these nonquantitative assessments, previous studies
9-12 were able to show that OMT could provide measurable improvement. However, while these results suggested improvements in patients’ conditions, they did not speak to the underlying causes of that improvement. The specific mechanism of OMT is still being investigated,
13-14 and one proposed mechanism, the biomechanical model, theorizes that somatic dysfunction is a result of asymmetry.
15 Savarese et al
16 provided support for the biomechanical model by stating that “a somatic dysfunction can present as tissue texture changes, asymmetry, restriction, and tenderness.” The biomechanical model is the basis for palpatory examinations, but because of inaccuracies in the identification of landmarks, better measurement techniques are needed.
Imaging techniques that have been used for the assessment of musculoskeletal (MSK) structures include plain film radiography, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography (US). Radiography and CT expose the patient to ionizing radiation, MRI is expensive, and these techniques require costly equipment and training to operate. US is inexpensive, radiation-free, and mobile, which makes it a valid option to measure musculoskeletal structures. Previously, US was found to accurately identify lumbar spine landmarks.
17 It was also used to assess the effects of OMT, including general OMT to the sacral region
18 and high-velocity, low-amplitude (HVLA) treatment to the lumbar spine.
19 To influence change in the targeted dysfunction, many OMT practitioners use numerous manipulation techniques for multiple related areas.
Our aim in this study was to assess the feasibility of using US to quantitatively measure asymmetry in the lumbar spine before and after management with multiple OMT techniques.
All variables, including the thickness of the soft tissue and the distance between transverse processes, were expressed by the mean and standard deviation (SD). Asymmetry was calculated for rotation by measuring the soft tissue thickness from the skin to transverse process bilaterally, and for side-bending by comparing the distance between adjacent transverse processes bilaterally. Calculations were made between the left and right sides of the same segment using the following equations, which we adapted from a previous study:
18
Rotational asymmetry = | RL−RR |
Side-bending asymmetry = | SBL−SBR |
RL is the rotational measurement of the left transverse process, and RR is the rotational measurement of the right transverse process; SBL is the measurement between the transverse processes on the left side, and SBR is between the transverse processes on the right side. Both asymmetry assessments were measured pre- and posttreatment.
To assess any change in asymmetry after treatment, pretreatment asymmetry was compared to posttreatment asymmetry using the following equations, which were adapted from a previous study
18:
Change in rotational asymmetry = | Pre-RL−Pre-RR |−| Post-RL−Post-RR |
Change in side-bending asymmetry = | PreSBL−PreSBR |− | PostSBL−PostSBR |
Pre-RL is the rotational measurement on the left side before OMT and Pre-RR is the rotational measurement on the right side before OMT; and Pre-SBL is the intertransverse ligament length on the left before OMT and Pre-SBR is the intertransverse ligament length on the right before OMT.
The absolute values allowed us to analyze the group together regardless of the direction of rotation. Without the absolute values, the right and left (positive and negative) asymmetries would negate each other and result in a population with no asymmetry. Additionally, greater absolute changes in participants with greater height and mass could introduce bias into our data. We did not have a mechanism to distinguish whether large changes in absolute value were due to the relative size of the participant's anatomy or whether the participants possessed a more significant dysfunction; this is an area for further research. To eliminate this bias, we also represented the changes as mean (%) improvement for the entire group (
Table 2) and the subgroups (
Table 3).
Table 2.
Lumbar Spine Asymmetry Before and After OMT
| | Mean asymmetry | | | | | |
Parameters | Participants, n | Before OMT (cm) | After OMT (cm) | Change in asymmetry (cm) | Mean % improvement | Asymmetry decreased, n | Asymmetry increased, n | P value |
Rotation | 20 | 0.28 | 0.14 | 0.14 | 12.93 | 13 | 7 | 0.01 |
Side-bending | 16 | 0.23 | 0.21 | 0.03 | −89.07 | 9 | 7 | 0.71 |
Table 2.
Lumbar Spine Asymmetry Before and After OMT
| | Mean asymmetry | | | | | |
Parameters | Participants, n | Before OMT (cm) | After OMT (cm) | Change in asymmetry (cm) | Mean % improvement | Asymmetry decreased, n | Asymmetry increased, n | P value |
Rotation | 20 | 0.28 | 0.14 | 0.14 | 12.93 | 13 | 7 | 0.01 |
Side-bending | 16 | 0.23 | 0.21 | 0.03 | −89.07 | 9 | 7 | 0.71 |
×
Table 3.
Rotation Asymmetry Subgroups
| | Mean asymmetry, cm | | |
| Participants, n | Before OMT | After OMT | Change in asymmetry | Mean % change | P value |
Increased asymmetry | 7 | 0.15 | 0.24 | −0.08a | −80.33a | .29 |
Decreased asymmetry | 13 | 0.35 | 0.09 | 0.26 | 63.15 | .001 |
| | P=.02 | P=.04 | | | |
Table 3.
Rotation Asymmetry Subgroups
| | Mean asymmetry, cm | | |
| Participants, n | Before OMT | After OMT | Change in asymmetry | Mean % change | P value |
Increased asymmetry | 7 | 0.15 | 0.24 | −0.08a | −80.33a | .29 |
Decreased asymmetry | 13 | 0.35 | 0.09 | 0.26 | 63.15 | .001 |
| | P=.02 | P=.04 | | | |
×
Statistical analysis included using an unpaired t test to examine the difference in soft tissue thickness between the sides with and without spinal asymmetry and using a 2-tailed paired t test to analyze the difference in soft tissue thickness before and after OMT. Intra- and interobserver reliability were tested using intraclass correlation coefficient (ICC). The correlation between US findings and osteopathic assessments was analyzed using Pearson correlation coefficient (PCC). A P value less than .05 was considered statistically significant. All statistical analysis was conducted by using SPSS software (SPSS version 25, IBM).
Our results suggest that using 2-dimensional grayscale sonography is feasible to quantify lumbar asymmetry and to assess the efficacy of OMT in the improvement of lumbar asymmetry. US seems to be an effective tool to measure lumbar asymmetry in a neutral position and to monitor the improvement in dysfunctional vertebrae after targeted OMT. A previous study
19 looked at transverse processes proximal to the vertebral bodies. However, by examining the most posterolateral point of the transverse process, we are able to assess the transverse processes distally, which is the landmark that demonstrates the greatest movement.
We used 2 US operators who were blinded to the osteopathic diagnosis, and 3 observers made US measurements to eliminate measurement bias. Ultimately, we observed favorable intra- and interobserver reliability in performing US—not only in acquiring US images but also in measuring soft tissue thickness and the distance between the most distal portion of transverse processes. ICC results suggested that both online technique and offline processing produced reliable and reproducible identification and measurement of the lumbar landmarks (
Table 4).
When evaluating the sensitivity of US compared with palpation, our PCC results suggested a significant correlation between US and palpatory diagnosis. Research has shown that medical students are capable of palpating asymmetrical differences as small as 4 mm in models.
21 A PCC of 0.62 suggests that while palpation may be more sensitive, US may be an effective way to confirm palpatory diagnosis quantifiably. This finding may have important applications in an educational setting when teaching palpation techniques.
The statistically significant decrease in rotational asymmetry suggests that OMT using varied techniques improves lumbar spine somatic dysfunction. Because we used multiple treatment modalities on multiple biomechanically related structures, our data is inconclusive as to which OMT techniques produced the most significant results. Future studies could limit the type of OMT used and the structures treated.
Side-bending asymmetry did not show significant improvements, which may indicate difficulties in assessing this plane of motion either by palpatory or US methods. Additionally, participants who demonstrated significant improvement had more asymmetry before OMT than participants in the group who did not show significant improvement. This finding may indicate that the group that did not improve had less somatic dysfunction present before receiving treatment and were subsequently less affected by the treatment received.
This study was limited by a small sample size, the lack of comparison between asymptomatic participants as a control group and symptomatic patients as a variable group, and the absence of intra- and interobserver reliability tested in performing osteopathic assessments. US was performed immediately after OMT, and the effect of OMT days or weeks posttreatment was not assessed. Future studies should include a larger sample size for greater statistical validity, a control group that receives no treatment and a treatment group of participants who demonstrate symptoms of lower back pain, and dynamic US measurements in addition to static measurements. The longitudinal effects of OMT should also be examined.
We thank Siemens Medical Solutions for loaning the ultrasonography scanner used in this study. We also thank Jan Pryor, DO, Judy Caldwell, DO, Chris Edwards, DO, Keith Bodrero, DO, and Amanda O'Loughlin, OMS III, for providing diagnoses, OMT, and technical support to this study.