October 2007 Volume 37, No. 10

Rehabilitative Ultrasound Imaging: When Is a Picture Necessary?

Deydre S. Teyhen, Maj John D. Childs, Timothy W. Flynn

In this issue of the journal, we explore rehabilitative ultrasound imaging's potential as a tool that physical therapists use in examining low back muscle function. As an assessment tool, RUSI can assist practitioners in recognizing impairments such as a decreased ability to increase muscle thickness (eg, transversus abdominis or multifidus) during specific physical tasks, excessive use of more global muscles (eg, rectus abdominis or erector spinae muscles) during low-level activities, and muscular atrophy. Identifying these impairments can help practitioners formulate a specific exercise program matched to the patient's underlying impairments during early stages of rehabilitation. From a treatment perspective, RUSI can provide feedback to both the physical therapist and patient that may help determine which verbal or tactile cues are most effective to facilitate proper performance of therapeutic exercises during the early phase of rehabilitation. Additionally, it may assist physical therapists in their decision-making process related to exercise prescription and progression. Finally, RUSI may help determine when specific impairments have been sufficiently addressed to permit the exercise progression necessary to achieve maximal pain-free function.

J Orthop Sports Phys Ther. 2007;37(10):579-580. doi:10.2519/jospt.2007.0109

KEY WORDS: rehabilitative ultrasound imaging, low back

Rehabilitative Ultrasound Imaging of the Posterior Paraspinal Muscles

Maria Stokes, Julie A. Hides, Kyle B. Kiesel, James M. Elliott, Paul W. Hodges

SYNOPSIS: Interest in rehabilitative ultrasound imaging (RUSI) of the posterior paraspinal muscles is growing, along with the body of literature to support integration of this technique into routine physical therapy practice. This clinical commentary reviews how RUSI can be used as an evaluative and treatment tool, and proposes guidelines for its use for the posterior muscles of the lumbar and cervical regions. Both quantitative and qualitative applications are described, as well as measurement reliability and validity. Measurement of morphological characteristics of the muscles (morphometry) in healthy populations and people with spinal pathology are described. Preliminary normal reference data exist for measurements of cross-sectional area (CSA), linear dimensions (muscle depth/thickness and width), and shape ratios. Compared to individuals without low back pain, changes in muscles' size at rest and during the contracted state have been observed using RUSI in people with spinal pathology. Visual observation of the image during contraction indicates that RUSI may be a valuable biofeedback tool. Further investigation of many of these observations is required using controlled studies to provide conclusive evidence that RUSI enhances clinical practice.

J Orthop Sports Phys Ther. 2007;37(10):581-595, published online 29 August 2007. doi: 10.2519/jospt.2007.2599

KEY WORDS: cervical muscles, lumbar muscles, lumbar spine, neck, morphometry, sonography

A Comparison of Select Trunk Muscle Thickness Change Between Subjects With Low Back Pain Classified in the Treatment-Based Classification System and Asymptomatic Controls

Kyle B. Kiesel, Frank B. Underwood, Carl G. Mattacola, Arthur J. Nitz, Terry R. Malone
STUDY DESIGN: Cross-sectional descriptive. OBJECTIVES: To investigate if muscle thickness change, as measured with rehabilitative ultrasound imaging (RUSI), is different across subgroups of patients with low back pain (LBP) classified in the Treatment-Based Cassification (TBC) system when compared to controls. BACKGROUND: Researchers have demonstrated that subgroups of patients with LBP exist and respond differently to treatment, challenging the assertion that LBP is "nonspecific." The TBC system uses 4 categories (stabilization, mobilization, direction-specific exercise, or traction) to subgroup patients. Recently, researchers have demonstrated impairments of the transverse abdominis (TrA) and lumbar multifidus (LM) in those with LBP, regardless of classification. Although distinct differences in impairments have been identified between sub-groups, TrA and LM impairments have not been studied and may be present across categories of the TBC system. METHODS AND MEASURES: RUSI was utilized to measure percent thickness change from rest to contracted state during a voluntary task of the TrA and during an upper extremity task known to activate the LM in 56 subjects classified in the TBC system and 20 controls. RESULTS: During the prone upper extremity lifting task with a hand weight, there was a significant group difference for the LM at L4-L5 (P = .03) and at L5-S1 (P = .04), and during volitional activation for the TrA (P<.01). Post-hoc testing revealed the differences were between controls and both the direction-specific and stabilization categories at the L4-L5 level, between control and direction-specific category for the L5-S1 level, and between controls and all 3 categories for the TrA. CONCLUSION: Deficits in the ability to generate muscle thickness changes in the TrA and LM occurred across categories of the TBC system. Intervention studies should be performed to determine if intervention can correct these deficits and if deficit corrections are related to outcomes.

J Orthop Sports Phys Ther. 2007;37(10):596-607, published online 28 August 2007. doi:10.2519/jospt.2007.2574. The original article was corrected in March 2008, and the amended article PDF is provided here. Please see Correction: A comparison of select trunk muscle thickness change between subjects with low back pain classified in the treatment-based classification system and asymptomatic controls. J Orthop Sports Phys Ther. 2008;38(3):161.

KEY WORDS: multifidus, sonography, spine stabilization, therapeutic exercise, transverse abdominis

Intrarater and Interrater Reliability of Assessment of Lumbar Multifidus Muscle Thickness Using Rehabilitative Ultrasound Imaging

Tracy L. Wallwork, Julie A. Hides, Warren R. Stanton
STUDY DESIGN: Within-session intrarater and interrater reliability study. OBJECTIVE: To establish the intrarater and interrater reliability of thickness measurements of the multifidus muscle in a parasagittal plane, conducted by an experienced ultrasound operator and a novice assessor. BACKGROUND: There is considerable evidence for the important role of the multifidus muscle in segmental stabilization of the lumbar spine. The cross-sectional area of the multifidus muscle has been assessed in healthy subjects and patients with low back pain using real-time ultrasound imaging. However, few studies have measured the thickness of the multifidus muscle using a parasagittal view. METHODS AND MEASURES: The thickness of the multifidus muscle was measured at rest, using real-time ultrasound imaging, in 10 subjects without a history of low back pain at the levels of the L2-3 and L4-5 zygapophyseal joints. The measure was carried out 3 times at each level by 2 assessors (1 experienced, 1 novice). Intrarater (model 3) and interrater (model 2) reliability was assessed by calculation of an F statistic (analysis of variance), the intraclass correlation coefficient (ICC), and the standard error of measurement (SEM). RESULTS: On the basis of an average of 3 trials, the 2 operators showed very high interrater agreement on the measurement of thicknesses at the L2-3 level (ICC_2,3= 0.96; 95% CI:0.84 to 0.99) and the L4-5 vertebral level (ICC_2,3= 0.97; 95% CI:0.87 to 0.99), with no systematic differences in muscle size across operators (p>.05). Interrater reliability was relatively lower for the L2-3 level (ICC_2,1= 0.85; 95% CI:0.51 to 0.96) than the L4-5 level (ICC_2,1 = 0.87; 95% CI:0.52 to 0.97) when a single trial per rater was used, but these values still indicated a high level of agreement. In addition, the novice and experienced operator produced reliable intrarater measurements at L2-3 (ICC_3,1= 0.89; 95% CI: 0.72-0.97 and 0.94; 95% CI: 0.86-0.99) and at L4-5 (ICC_3,1= 0.88; 95% CI: 0.68-0.97 and 0.95; 95% CI: 0.86-0.99), with no systematic differences in muscle size across trials (P>0.05). The consistently low SEM values also indicate low measurement error. CONCLUSION: A novice and an experienced assessor were both able to reliably perform this measure at rest for 2 vertebral levels using real-time ultrasound imaging. An average of 3 trials produced higher interrater reliability scores, though a single trial per rater was also reliable.

J Orthop Sports Phys Ther. 2007;37(10):608-612, published online 29 May 2007. doi:10.2519/jospt.2007.2418

KEY WORDS: back muscles, lumbar spine, muscle assessment, repeatability, ultrasonography

Improved Activation of Lumbar Multifidus Following Spinal Manipulation: A Case Report Applying Rehabilitative Ultrasound Imaging

Alexander Karl Brenner, Kyle B. Kiesel, Norman W. Gill, Christopher J. Buscema

STUDY DESIGN: Case report. BACKGROUND: The use of spinal manipulation as a treatment to facilitate neuromuscular control of the paraspinal musculature is not well described in the literature. The use of rehabilitative ultrasound imaging (RUSI) may offer a convenient way to investigate and document possible changes occurring in the lumbar multifidus associated with manipulation intervention. CASE DESCRIPTION: The patient was a 33-year-old male with a 21-year history of low back pain and left posterior thigh pain who presented with lumbar hypomobility and met a previously published clinical prediction rule for spinal manipulation. During examination, the patient was asked to perform a prone upper extremity lifting task to assess activation in the lumbar multifidus during an automatic task. Through palpation, the examiner noted a decreased contraction of the left multifidus between L4-S1 compared to the right. To explore this further, a decision was made to assess the multifidus with RUSI, which confirmed the activation deficit noted during palpation. A lumbar regional manipulation was performed with the intention of reducing spinal hypomobility and assessing changes in multifidus activation. Imaging of the multifidus muscles at the L4-5 and L5-S1 levels were obtained premanipulation, immediately postmanipulation, and 1 day after manipulation. OUTCOMES: An increased ability to thicken the multifidus during a prone upper extremity lifting task was noted immediately and 1 day after manipulation. Average percent change in thickness at the L4-5 and L5-S1 levels with the prone arm lift was 3.6% premanipulation, 17.2% immediately postmanipulation, and 20.6% approximately 24 hours postmanipulation. Improvements in the thickening of the multifidus muscle during the upper extremity lifting task were greater than 3 standard errors of the measurement. Other changes included immediate palpable improvement in the contraction of the multifidus during the upper extremity lifting task, along with the patient report of increased ease of lifting. DISCUSSION: In this case report we quantified the short-term influence of spinal manipulation on multifidus muscular activation using RUSI. No cause-and-effect claims can be made; however, the results provide preliminary evidence to suggest that spinal manipulation may influence multifidus muscle function. RUSI offers a convenient way to investigate and document these changes.

J Orthop Sports Phys Ther. 2007;37(10):613-619, published online 29 May 2007. doi:10.2519/jospt.2007.2470

KEY WORDS: motor control, reflexogenic, sonography

Rehabilitative Ultrasound Imaging of the Lower Trapezius Muscle: Technical Description and Reliability

Cliona O'Sullivan, Susanna Bentman, Kathleen Bennett, Maria Stokes
STUDY DESIGN: Exploratory and reliability study. BACKGROUND: Shoulder dysfunction is common and often difficult to diagnose and treat. The trapezius muscle is an important stabilizer and primary mover of the scapula. The potential use of rehabilitative ultrasound imaging (RUSI) to evaluate scapular muscle function warrants investigation. OBJECTIVES: To establish a procedure for imaging the thickness of the lower trapezius muscle and to examine reliability within and among investigators. METHODS: In 16 asymptomatic subjects (12 female, 4 male), aged 20 to 41 years, 3 investigators used RUSI to measure the thickness of the left lower trapezius muscle with the subject at rest in prone. Investigator 1 took 3 images on each of 2 days, while the other 2 investigators took 2 images each on the second day. All measurements of lower trapezius muscle thickness were made off-line, at a point 3 cm lateral to the lateral edge of the spinous processes. To also obtain within-scan reliability, 1 image taken by investigator 1, once displayed on the scanner's screen, was measured 3 times. Investigator 1 also measured lower trapezius muscle thickness 1 cm medial to this site. Reliability was examined using intraclass correlation coefficients (ICC) and the Bland and Altman plot. RESULTS: The intrarater within-scan reliability at the lateral site was ICC_3,3= 0.99, (95% CI: 0.98 to 1.0).The intrarater between-scan reliability (within-day) at the lateral site, medial site, and combined sites (mean of medial and lateral) were ICC_3,3= 0.96; (95% CI: 0.90 to 0.98); ICC_3,2= 0.90 (95% CI: 0.78 to 0.96); and ICC_3,2= 0.99 (95% CI: 0.99 to 1.0), respectively. Intrarater (between-day) reliability was good for the lateral site and combined sites (ICC_3,3= 0.91; 95% CI: 0.74 to 0.96 and ICC_3,3 = 0.90; 95% CI: 0.70 to 0.96, respectively) and moderate for the medial site (ICC_3,3= 0.89; 95% CI: 0.68 to 0.96). Interrater reliability (among investigators) was also moderate (ICC_{2, 2}= 0.88; 95% CI: 0.73 to 0.96). Mean lower trapezius muscle thickness was approximately 3.1 mm (SD, 0.8mm). CONCLUSION: Thickness of the lower trapezius muscle can be measured reliably with RUSI.

J Orthop Sports Phys Ther. 2007;37(10):620-626, published online 29 May 2007. doi:10.2519/jospt.2007.2446

KEY WORDS: morphology, morphometry, muscle size, scapular muscles, ultrasonography

Ultrasound Imaging as a Feedback Tool in the Rehabilitation of Trunk Muscle Dysfunction for People With Low Back Pain

Sharon M. Henry, Deydre S. Teyhen

SYNOPSIS: This commentary provides an overview of the current concepts and the emerging evidence related to rehabilitative ultrasound imaging (RUSI) for biofeedback purposes. Specifically, the role of RUSI to assess improvements in trunk muscle performance and motor learning will be discussed, highlighting the importance of retention and transfer testing to assess motor learning. The use of RUSI as an extrinsic (augmented) feedback tool and its ability to provide both knowledge of performance and knowledge of results information will be defined. An analysis of the limited available literature related to the role of RUSI as an augmented feedback tool to enhance motor skill acquisition related to the deep trunk muscles will be provided. Future research directions and priorities are recommended.

J Orthop Sports Phys Ther. 2007;37(10):627-634. doi:10.2519/jospt.2007.2555

KEY WORDS: motor control, multifidus, therapeutic exercise, transversus abdominis

Characterization of Lateral Abdominal Muscle Thickness in Persons With Lower Extremity Amputations

Barbara A. Springer, Norman W. Gill
STUDY DESIGN: Retrospective review. OBJECTIVES: To describe bilateral thickness of the lateral abdominal muscles at baseline and during an abdominal drawing-in maneuver (ADIM) in individuals with unilateral transtibial (TTA) or transfemoral (TFA) amputations. BACKGROUND: Although side-to-side symmetry of lateral abdominal muscles thickness has been established in healthy individuals, the degree of symmetry in those with unilateral lower extremity amputations remains unknown. Differences in lateral abdominal muscle thickness may exist based on prior findings of asymmetry and differences measured based on level of amputation in both the size and function of the iliopsoas and back extensor muscles. METHODS AND MEASURES: Seventy patients (69 males, 1 female) with traumatic unilateral lower extremity amputations (TTA, n = 39; TFA, n = 31) received a rehabilitative ultrasound imaging examination. Absolute thickness of the transversus abdominis (TrA) and the external and internal oblique muscles combined (EO+IO) were assessed bilaterally at baseline and during the ADIM. Symmetry was assessed using relative muscle thickness values at baseline. Percent increase in muscle thickness during the ADIM was used to investigate muscle function. Separate 2-by-2 mixed-model ANOVAs were used to compare both within-group (side of amputation versus nonamputated side) and between-group (TTA versus TFA) differences for thickness and function of the TrA and the EO+IO muscles. RESULTS: On the side of the amputation, the relative baseline thickness of the EO+IO measurement was greater (P<.05), while the relative baseline thickness of the TrA muscle was smaller (P<.05). But the mean differences side to side were small (1.3%) and unlikely to be clinically significant. Further, there were no differences in baseline muscle thickness between groups for the TrA (P = .95) or the EO+IO (P = .94) muscles. For thickness measurements during the ADIM, the TrA showed no side-to-side (P = .74) or group (P = .07) differences. Similarly, no side-to-side (P = .60) or group (P = .09) differences were found in the EO+IO thickness during the ADIM. CONCLUSIONS: Despite the limitations of retrospective review, these findings provide an initial reference data set for future studies. Bilateral symmetry of the lateral abdominal wall muscle thicknesses at baseline and during the ADIM for those with unilateral lower extremity amputations is comparable to healthy individuals. Future studies should consider the potential influences of low back pain and gait training on symmetry of muscle thickness and muscle function based on level of amputation.

J Orthop Sports Phys Ther. 2007;37(10):635-643, published online 29 August 2007. doi: 10.2519/jospt.2007.2532

KEY WORDS: rehabilitative ultrasound imaging, sonography, transfemoral, transtibial, transversus abdominis

The Use of Ultrasound Imaging to Measure Midfoot Plantar Fat Pad Thickness in Children

Diane L. Riddiford-Harland, Julie R. Steele, Louise A. Baur

STUDY DESIGN: Descriptive and reliability study. OBJECTIVES: To design a reliable imaging method to quantify the thickness of the medial midfoot plantar fat pad in the feet of young children and to determine any between-foot (right versus left) differences in thickness. BACKGROUND: Before we can establish whether persistent fat padding in the medial midfoot or a structural collapse of the longitudinal arch is the mechanism of flatter footprints displayed by obese children, a reliable method to quantify midfoot plantar fat pad thickness in children is required. METHODS AND MEASURES: A portable ultrasound imaging system was used to quantify medial midfoot plantar fat pad thickness for the right and left foot of 14 healthy children (mean ± SD: 3.8 ± 0.8 years) using 3 different measurement techniques. Intraclass correlation coefficients (ICC) and standard error of the measurement (SEM) were calculated to assess intrarater reliability of these measurement techniques. RESULTS: Medial midfoot plantar fat pad thickness (method 1, right foot) ranged from 3.1 to 4.9 mm. Similar values were observed for methods 2 and 3. The ICC values (0.82-0.94) and SEM values (0.12-0.23 mm) suggested that all 3 methods provided good reliability. Based on an ANOVA model, there was no significant interaction and no significant main effect for side, method, or day between the measurement techniques. CONCLUSIONS: We found ultrasonography to be a reliable field tool to quantify medial midfoot plantar fat pad thickness in children. Although there was no difference in reliability across the 3 measurement techniques, the technique in which the transducer was placed directly beneath the dorsal-navicular landmark was the most time-efficient procedure to measure the thickness of the midfoot plantar fat pad in young children.

J Orthop Sports Phys Ther. 2007;37(10):644-647, published online 20 June 2007. doi:10.2519/jospt.2007.2504

KEY WORDS: fat padding, feet, infants, sonography, ultrasonography

Abstracts

A selection of important abstracts of articles published in other journals.

J Orthop Sports Phys Ther. 2007;37(10):648-656.