Ultrasound imaging in rehabilitation: just a fad?

Potential role of physical labor and cultural views of menstruation in high incidence of pelvic organ prolapse in Nepalese women: a comparative study across the menstrual cycle

Introduction

Pelvic organ prolapse (POP) is a significant health concern for young Nepali women, with potential risk factors including pelvic floor trauma from vaginal delivery and heavy lifting. The prevalence of symptomatic POP (SPOP) among nulliparous women in Nepal is 6%, while the general population of Nepali women aged 15-49 years reports a prevalence of 7%. Surprisingly, the average age of SPOP onset in Nepal is 27 years, challenging the assumption that postmenopausal age and vaginal delivery are the sole risk factors. This study aims to investigate the influence of increased intra-abdominal pressure (IAP) during lifting tasks on pelvic organ descent in Nepali women across different menstrual cycle stages.

Methods

The study included 22 asymptomatic Nepali women aged 18-30 years who regularly engage in heavy lifting. Intra-abdominal pressure was measured intra-vaginally during typical and simulated lifting tasks, which encompassed various scenarios such as ballistic lifting, ramped lifting, and pre-contraction of pelvic floor muscles, as well as coughing, Valsalva maneuver, and pelvic floor contractions. Pelvic floor displacement was recorded using transperineal ultrasound during menstruation, ovulation, and the mid-luteal phase.

Results

Results indicated that pelvic floor displacement was greater during menstruation than ovulation when performing a simulated ballistic lifting task (6.0 ± 1.6 mm vs. 5.1 ± 1.5 mm, p = 0.03, d = 0.6). However, there was no significant difference in pelvic floor displacement during lifting when the pelvic muscles were pre-contracted.

Conclusion

These findings suggest that lifting heavy loads during menstruation may increase the risk of stretching and injuring pelvic floor supportive tissues, potentially contributing to SPOP in young Nepali women. Pre-contracting pelvic floor muscles during lifting tasks may offer a protective effect. Understanding these factors could aid in developing targeted preventive measures and raising awareness about the impact of heavy lifting on pelvic floor health among Nepali women.

The effect of activation of thoracolumbar fascia on the thickness of abdominal muscles: An ultrasonographic study

Objectives

This study aims to evaluate the changes in the ultrasonographic thickness of transversus abdominis and internal oblique muscles during bridge with arm extension compared to bridge and abdominal hollowing.

Patients and methods

Between March 1^st, 2019 and March 29^th, 2019, a total of 30 healthy individuals (15 males, 15 females; mean age: 28.8±8.1 years; range, 21 to 52 years) among hospital staff were included. Thickness of transversus abdominis, internal, and external oblique muscles of the participants were evaluated using ultrasound during four positions (rest, abdominal hollowing, bridge, and bridge with arm extension).

Results

The mean body mass index was 23.8±4.1 kg/m². The thickness of transversus abdominis and internal oblique muscles increased during all positions (p<0.001), compared to rest. The thickness during bridge with arm extension was greater than abdominal hollowing and bridge.

Conclusion

Co-activation of latissimus dorsi and gluteus maximus muscles during abdominal contraction increases the thickness of internal oblique and transversus abdominis muscles greater than abdominal contraction alone or co-activation of gluteus maximus alone. Simultaneous isometric contraction of latissimus dorsi muscle may enhance abdominal muscle function.

Clinical utility of ultrasonography imaging in musculoskeletal conditions: A Systematic review and Meta-analysis

Optimising ultrasonography imaging (UI) applications for clients is a highly specific and sensitive add-on method. The aim of this meta-analysis was to systematically evaluate the clinical utilisation of UI in musculoskeletal conditions by rehabilitation providers in the past decade. Two reviewers independently assessed relevant research articles from five databases electronically (Medline, Cochrane Library, EMBASE, ProQuest, EBSCO) and screened titles and abstracts based on predefined eligibility criteria (2010- 2020). A total of 147 articles were screened for eligibility by two reviewers independently, and any disagreements were resolved by another reviewer using Rayyan QCRI software. Ninety-seven duplicates were removed, and after excluding 21 studies, 16 randomized controlled trials were included and full texts retrieved. Data were synthesised using Revman 5.4 software for qualitative analysis and risk-of-bias assessment. Four similar studies were statistically analysed for heterogeneity of abdominal muscle contraction ratios. Two interventional studies were also analysed to assess the effect of feedback. The diagnostic application of UI was investigated using a consistent amount of literature, though from a rehabilitation perspective the literature is inconclusive. The clinical utility of UI in rehabilitation by physical therapists is conclusive and has potential to advance clinical practice. Further well-designed randomized controlled trials minimising selection biases will help improve the quality in this domain. Critical reflection, clinical reasoning, and mutual goal setting will help practising physical therapists to scrutinize the clinical practice more objectively.

Intraclass correlation coefficient of trunk muscle thicknesses in different positions measured using ultrasonography

[Purpose] This study aimed to clarify the required number of measurements to calculate trunk muscle thickness at each position. [Participants and Methods] The participants were 30 elderly males aged >65 years. The right lumbar multifidus (L2), lumbar multifidus (L5), erector spinae, transversus abdominis, internal oblique, and external oblique muscle thicknesses were measured on longitudinal images obtained using ultrasonography in the lying, sitting, and standing positions. Two measurement values for each muscle thickness was used to calculate the intraclass correlation coefficient (1.1–1.5). [Results] The intraclass correlation coefficients of the abdominal muscle thickness measurements with “great reliabilities” were as follows: 1.3–1.5 for the external oblique muscle and 1.2–1.5 for the internal oblique and transversus abdominis muscles in the lying position; 1.3–1.5 for the external oblique and transversus abdominis muscles and 1.2–1.5 for the internal oblique muscle in the sitting position; the intraclass correlation coefficient in the standing position was 1.5 for the external oblique muscle 1.1–1.5 for the internal oblique muscle and 1.3–1.5 for the transversus abdominis muscle. In all the positions, the intraclass correlation coefficient of the measurements of the back-muscle thicknesses ranged from 1.1 to 1.5 for the right lumbar multifidus (L2), lumbar multifidus (L5), and erector spinae. [Conclusion] Depending on the posture, the abdominal muscles require multiple measurements, whereas the back muscles only require a single measurement.

Short-Term Morphological Changes in Asymptomatic Perimandibular Muscles after Dry Needling Assessed with Rehabilitative Ultrasound Imaging: A Proof-of-Concept Study

Facial anatomical structures are not easily accessible to manual palpation. The aim of our study is to objectively assess temporomandibular joint and perimandibular muscles dimensions by means of sonographic measurements before and after dry needling (DN) in asymptomatic subjects. Seventeen subjects participated in this before-after study with a within-subject control. After random allocation, one side of the face was used for the intervention and the contralateral as control. DN was performed on the temporal, masseter, and sternocleidomastoid muscles. Each subject was examined bilaterally before, immediately after, and one month after the intervention through Rehabilitative Ultrasound Imaging (RUSI) of the temporomandibular articular disc and the three target muscles. Maximum mouth opening was measured at baseline and at one month. After a single DN session, articular disc thickness significantly decreased; muscles’ thicknesses (except for temporal thickness) significantly decreased immediately and at follow-up on the treated side; no significant changes resulted for the control side. The maximum mouth opening increased from 4.77 mm to 4.86 mm. RUSI may be useful to assess the dimensions and thickness of the temporomandibular disc and muscles before and after an intervention. DN influences muscle morphology, and it has a positive influence on mouth opening in the short term.

Exploring the use of ultrasound imaging by physiotherapists: An international survey

BACKGROUND

National surveys in New Zealand, Australia and the United Kingdom suggest ultrasound imaging (USI) use by physiotherapists is increasing. However, concerns exist regarding clarity for scopes of practice, and availability and standardisation of training.

OBJECTIVES

To investigate physiotherapists' understanding of scopes of practice for the use of USI; clarify the professional contexts, clinical uses and levels of training; and identify barriers preventing physiotherapists' USI use.

DESIGN

A cross-sectional, observational survey.

METHODS

An Internet-based survey, offered in 20 different languages, was used including items covering five domains: (1) demographic and professional characteristics; (2) knowledge of scope of practice; (3) USI use; (4) USI training content and duration; and (5) perceived barriers to physiotherapists' use of USI.

RESULTS

1307 registered physiotherapists from 49 countries responded; 30% were unsure of the scope of practice for physiotherapists' USI use. 38% of participants were users of USI, reporting varied contexts and clinical uses, reflected in the broader categories of: (i) biofeedback; (ii) diagnosis; (iii) assessment; (iv) injection guidance; (v) research; (vi) and teaching. The training users received varied, with formal training more comprehensive. 62% were non-users, the most common barrier was lack of training (76%).

CONCLUSION

These findings suggest physiotherapists' USI use is increasing in various contexts; however, there is uncertainty regarding scopes of practice. There are discrepancies in training offered, with a lack of training the most common barrier to physiotherapists' use of USI. International guidelines, including a USI training framework, are needed to support the consistent and sustainable use of USI in physiotherapy.

Assessment of the influence of global and local exercises on core stabilization mechanisms: randomized controlled trial

BACKGROUND

Over the last few years, various concepts of applying core stabilization mechanisms in the formation of human motor function have come to existence. The objective of the research was to assess the influence of two types of core stability training on deep abdominal muscle thickness and on global trunk mobility.

METHODS

The study involved 108 individuals divided into 3 groups: LT (local training), performing the stability training based on locally isolated work of the transversus abdominis muscle; GT (global training), performing the training based on global movement patterns; and CG (control group), who did not undergo the training. The workout programs comprised 4 weeks of the exercise, 4 times a week. The measurement of the observed muscle thickness was carried out by means of ultrasound imaging. Trunk mobility was evaluated based on the toe-touch test, as well as the measurement of lateral flexion ranges. All the measurements were performed before the workout programs, right after finishing and 2 weeks after the end of the training cycle.

RESULTS

Both training concepts have an impact on deep abdominal muscle thickness; however, in the LT group, significant improvement was noted with regard to the transversus abdominis, whereas in the GT group the improvement concerned the external oblique muscle. Both training methods also improved trunk mobility in the sagittal and frontal plane.

CONCLUSIONS

The results we have obtained imply that both concepts of core stability training affect the human body at a structural as well as functional level. The application of the described training methods may not only provide measurable benefits in the field of clinical physiotherapy, for instance in the treatment of spine-related back pain, but also in motor training designed to improve athletes' performance and to minimize the risk of injury.

Influence of phase of respiratory cycle on ultrasound imaging of deep abdominal muscle thickness

BACKGROUND

It is difficult to evaluate the transversus abdominis (TrA) and internal oblique (IO) due to their dual role in both trunk control and breathing.

OBJECTIVES

To investigate whether TrA and IO thickness as measured by ultrasound differs across the respiratory cycle in upright standing.

DESIGN

Observational study.

METHODS

Thickness of TrA and IO was measured with ultrasound in 67 subjects in upright standing. Measures were performed 3 times and by 2 assessors, at the end of relaxed expiration, at the end of a full inspiration, and at the end of full expiration. Differences were assessed by ANOVA. Intra- and inter-rater reliability (of a single measure and the average of 3 measures) were assessed by intra-class correlation (ICC).

RESULTS

Thickness of the TrA and IO was higher at full expiration than at the end of relaxed expiration (p < 0.001), and in turn compared to at full inspiration (p < 0.001). Intra-rater reliability was excellent at all respiratory phases (ICC 0.76-0.87). Whereas inter-rater reliability for a single measure was only fair to good for TrA (ICC 0.52-0.71) and good to excellent for IO (ICC 0.61-0.78), the inter-rater reliability of the average was excellent at all respiratory phases (ICC 0.75-0.90).

CONCLUSIONS

Thickness of TrA and IO increases when lung volume decreases. The intra- and inter-rater reliability of an average measure were excellent at the end of relaxed expiration, full inspiration and full expiration. This provides new opportunities to evaluate the deep abdominal muscles, and their role in respiration, in a physiotherapeutic setting.

Rehabilitative Ultrasound Imaging Evaluation in Physiotherapy: Piloting a Systematic Review

Background: Research of ultrasound use in physiotherapy and daily practice has led to its use as an everyday tool. Methods: The aims were: (1) Checking the proposed systematic review protocol methodology; (2) evaluating the evidence from the last five years; and (3) coordinating the work of the team of reviewers in performing a complete systematic review. Thus, this is a pilot study prior to a full systematic review. The findings in databases related to health sciences with the meta-search engine Discovery EBSCO, Covidence, and Revman were used. Inclusion and exclusion criteria were described for eligibility. Results: Search provided 1029 references regarding the lumbar region on ultrasound scans. Of these, 33 were duplicates. After Covidence, 996 studies were left for screening. A full-text reading brought one randomized clinical trial (RCT). Conclusions: Validity and reliability references were found. The most suitable points were novice versus expert, and ultrasound versus electromyography (EMG) with just one RCT cohort, and observational and case reports. The lines of investigation increasingly endorsed the validity of using ultrasound in physiotherapy. Post-acquisition image analysis could also be a future line of research.

Effect of core muscle thickness and static or dynamic balance on prone bridge exercise with sling by shoulder joint angle in healthy adults

[Purpose] To date, core muscle activity detected using ultrasonography during prone bridge exercises has not been reported. Here we investigated the effects of core muscle thickness and balance on sling exercise efficacy by shoulder joint angle in healthy individuals. [Subjects and Methods] Forty-three healthy university students were enrolled in this study. Ultrasonography thickness of external oblique, internal oblique, and transversus abdominis during sling workouts was investigated. Muscle thickness was measured on ultrasonography imaging before and after the experiment. Dynamic balance was tested using a functional reaching test. Static balance was tested using a Tetrax Interactive Balance System. [Results] Different muscle thicknesses were observed during the prone bridge exercise with the shoulder flexed at 60°, 90° or 120°. Shoulder flexion at 60° and 90° in the prone bridge exercise with a sling generated the greatest thickness of most transversus abdominis muscles. Shoulder flexion at 120° in the prone bridge exercise with a sling generated the greatest thickness of most external oblique muscles. [Conclusion] The results suggest that the prone bridge exercise with shoulder joint angle is an effective method of increasing global and local muscle strength.

Current rehabilitation applications for shoulder ultrasound imaging

The available body of knowledge on shoulder ultrasound imaging has grown considerably within the past decade, and physical therapists are among the many health care professions currently exploring the potential clinical integration of this imaging technology and the knowledge derived from it. Therefore, the primary purpose of this commentary was to review the recent evidence and emerging uses of ultrasound imaging for the clinical evaluation of shoulder disorders. This includes a detailed description of common measurement techniques along with their known clinimetric properties. Specifically provided are critical appraisals of the existing measures used to estimate soft tissue and bony morphometry, muscle contractile states, and lean muscle density. These appraisals are intended to help clinicians clarify the scope of physical therapy practice for which these measurement techniques are effectively utilized and to highlight areas in need of further development.

Reliability of rehabilitative ultrasonography to measure transverse abdominis and multifidus muscle dimensions

BACKGROUND

Lumbar paraspinal muscles play an important role in providing both mobility and stability during dynamic tasks. Among paraspinal muscles, transverse abdominis and lumbar multifidus have been of particular interest as active stabilizers of the lumbar spine. These muscles may become dysfunctional in chronic low back pain (CLBP). Low back injury can result in muscle inhibition and control loss that cannot recover spontaneously, and specific exercises are required to stimulate their recovery.

OBJECTIVES

The purpose of this study was to test the reliability of ultrasonography to measure muscle dimensions and to present a reliable method for measuring transverse abdominis and lumbar multifidus as stabilizing muscles of the lumbar spine.

SUBJECTS AND METHODS

Fifteen healthy participants (18-55 year olds) were evaluated by a radiologist using ultrasonography (ES500) with two probes (50mm linear 7.5 MHZ and 70 mm curvilinear 3.5 MHz). The muscle thickness of transverse abdominis and the anterior-posterior diameter and cross sectional area of the LMF were measured. To determine within and between days reliabilities, second and third measurements were repeated with half an hour and one week intervals, respectively.

RESULTS

Intraclass correlation coefficient for left and right showed good to high reliability for the cross sectional area of lumbar multifidi (0.74 and 0.88, respectively) as well as the anterior-posterior dimensions of lumbar multifidi (0.89 and 0.91, respectively) and transverse abdomini thickness (0.73 and 0.85, respectively).

CONCLUSIONS

Rehabilitative ultrasonography is a reliable and non-invasive instrument to measure muscle thickness. The method used in this study is a reliable way to measure lumbar stabilizing muscles.

Diagnostic and procedural imaging curricula in physical therapist professional degree programs

STUDY DESIGN

Descriptive survey.

OBJECTIVE

To describe the status of diagnostic and procedural imaging curricula within United States physical therapist professional degree programs.

BACKGROUND

As patient direct access to physical therapy services increases, the ability to refer patients directly for diagnostic imaging could promote more efficient delivery of care. Appropriate patient referral is contingent on physical therapists having the requisite knowledge base and skills. While evidence describing imaging competence of physical therapists with advanced training in military institutions exists, evidence is lacking for other physical therapists, including new graduates of physical therapist professional degree programs.

METHODS

Faculty members teaching imaging at 206 United States physical therapist professional degree programs recognized by the Commission on Accreditation in Physical Therapy Education were recruited via e-mail correspondence. An e-mail attachment included the survey on which faculty reported imaging curricula and faculty qualifications, attitudes, and experiences.

RESULTS

Faculty from 155 (75.2%) programs responded to the survey, with imaging being included in the curriculum of 152 programs. Content was integrated by required standalone courses or clinical science track courses, and/or through elective courses. The average reported estimate of imaging contact hours was 24.4 hours (range, 2-75 hours). Emphasis was on the musculoskeletal system, including 76.3% of the required standalone course content. Student competence was assessed in 147 (96.7%) programs, primarily by written (66.7%) and practical (19.7%) examinations. Faculty rated student competence on a scale of 1 (not competent) to 5 (competent), with ratings ranging from a high of 4.0 (identifying normal anatomy on plain-film radiography) to a low of 1.9 (identifying common tissue pathological processes/injuries on ultrasound).

CONCLUSION

While a majority of programs reported including imaging curricula, variability was noted in all curricular aspects. These results may serve as a benchmark for faculty to assess existing curricula, allow for further development of imaging curricula, and provide a benchmark for the profession regarding current level of training for recent graduates of entry-level physical therapist professional degree programs.

A physiotherapy perspective of musculoskeletal imaging in sport

This paper presents a physiotherapy perspective on the role that imaging is now playing in the diagnosis and management of musculoskeletal and sporting injuries. Although the Royal College of Radiologists and the UK Chartered Society of Physiotherapy were founded in the latter part of the nineteenth century, it is 100 years later that developments in the UK NHS have led to increased roles for non-medical healthcare professionals and allied health professionals, such as physiotherapists, in an extended clinical role. Physiotherapists, perhaps because of their knowledge of clinical and applied anatomy, have keenly taken up the opportunities offered to request and interpret imaging in its various forms; the most commonly available are plain radiography, musculoskeletal ultrasound and MRI. This has meant taking formal courses under the auspices of universities with mentorship and tutoring within the clinical setting, which are part of a continuing professional development. The ability to request several forms of imaging has enhanced physiotherapy practice and has increased the appreciation of the responsibilities which accompany this new role.

Use of ultrasound imaging by physiotherapists: a pilot study to survey use, skills and training

OBJECTIVE

This study aimed to design and pilot a questionnaire to survey the use of ultrasound imaging (USI) by physiotherapists in the United Kingdom (UK), the type and content of ultrasound training physiotherapists using USI had undertaken and their perceived future training needs.

BACKGROUND

The use of USI by physiotherapists is becoming increasingly common but is highly operator dependent and there are safety and professional issues regarding use in physiotherapy practice. Currently there are no specific training guidelines relating to physiotherapists using USI.

METHODS

A questionnaire was developed, based on research literature and guidelines. Twelve experts in USI commented on the content and design. The electronic on-line questionnaire was piloted on groups that were likely to be users of USI.

RESULTS

Forty-six respondents completed the questionnaire. Results indicated that USI is used predominantly for biofeedback and there are many unmet training needs. Respondents reported a mismatch between techniques for which they had received training and those that they used in practice and indicated a more structured training framework is required.

CONCLUSIONS

The development and piloting of the questionnaire provides a starting point for a more extensive evaluation of how USI is being used, the training needs of physiotherapists and benefits as a biofeedback tool. Refinement is needed and replication in a larger sample. Results could assist the development of a structured formal training framework encompassing key skills.

Ultrasound imaging and muscle function

There is a growing trend in the physical therapy profession to use conventional grayscale brightness (B-mode) ultrasound imaging (USI) as a tool to assess the morphological (form and structure) and morphometric (measures of form) characteristics of muscle, and to use these findings to draw conclusions regarding muscle function. This trend is reflected in numerous published investigations. As many physical therapists may lack training in the principles and instrumentation underlying USI use, it is critical that therapists gain a clear understanding of the information that USI can, and cannot, provide about muscle function before employing the technique for either research or clinical applications. Failure to do so may result in the propagation of inaccurate terminology and beliefs. This paper aims to clarify the role that USI has in the assessment of muscle function, first, by briefly reviewing how conventional grayscale B-mode ultrasound images and clips are generated, and second, by summarizing the types of information that these images can provide. It also discusses the various factors that need to be considered when interpreting a dynamic USI assessment of muscle specifically as it relates to the assessment of muscle function.

Discriminative and reliability analyses of ultrasound measurement of abdominal muscles recruitment

Rehabilitative ultrasound imaging has a great potential to be used as a tool in the assessment of trunk muscle function in patients with low back pain (LBP). However, a further investigation of the discriminative ability of this tool as well as the effect of operators' levels of training on reliability is warranted. Discriminative analysis of ultrasound and electromyography (EMG) measurements of transversus abdominus (TrA), obliquus internus (OI), and obliquus externus (OE) muscles function between people with and without LBP and the effect of operator's training on reliability of TrA muscle function of chronic LBP patients were conducted. For the discriminative study, measurements were collected from 10 subjects with LBP and 10 matched controls during isometric low load tasks with their limbs suspended. For the reliability study, in stage 1 the reliability of single ultrasonographic static images involved 4 operators (1 trained and 3 non-trained), whereas, in stage 2, two operators (1 trained and 1 non-trained) were used to determine the reliability of TrA thickness change. Methods used in the statistical analysis were pearson correlation and receiver operating characteristic curve for the discriminative study and intraclass correlation coefficient (ICC) for the reliability study. While ultrasound measures of OE muscle function showed poor association with EMG (r = 0.28, p = 0.22), TrA and OI function showed moderate to excellent association (TrA: r = 0.74, p < 0.000; OI: r = 0.85, p < 0.000). Ultrasound and EMG measures of TrA and OI function discriminated LBP patients from controls. Reliability of the assessment of TrA function with a trained operator (ICC = 0.92; 95% CI: 0.81-0.97) was substantially higher than a non-trained one (ICC = 0.44; 95% CI: -0.41-0.78). In conclusion, ultrasound measures of deep trunk function is a valid discriminative tool in LBP but highly dependent on operator's level of training.

Abdominal muscle size and symmetry at rest and during abdominal hollowing exercises in healthy control subjects

The symmetry of, and physical characteristics influencing, the thickness of the lateral abdominal muscles at rest and during abdominal exercises were examined in 57 healthy subjects (20 men, 37 women; aged 22-62 years). M-mode ultrasound images were recorded from the abdominal muscles at rest and during abdominal hollowing exercises in hook-lying. The fascial lines bordering the transvs. abdominis, obliquus internus and obliquus externus were digitized and the absolute thickness, relative thickness (% of total lateral thickness) and contraction ratio (thickness during hollowing/thickness at rest), as well as the asymmetry (difference between sides expressed as a percent of the smallest value for the two sides) for each of these parameters were determined for each muscle. Both at rest and during hollowing, obliquus internus was the thickest and transvs. abdominis the thinnest muscle. There were no significant differences between left and right sides for group mean thicknesses of any muscle; however, individual asymmetries were evident, with mean values for the different muscles ranging from 11% to 26%; asymmetry was much less for the contraction ratios (mean % side differences, 5-14% depending on muscle). Body mass was the most significant positive predictor of absolute muscle thickness, for all muscles at rest and during hollowing, accounting for 30-44% variance. Body mass index explained 20-30% variance in transvs. abdominis contraction ratio (negative relationship). The influence of these confounders must be considered in comparative studies of healthy controls and back pain patients, unless groups are very carefully matched. Asymmetries observed in patients should be interpreted with caution, as they are also common in healthy subjects.

Rehabilitative ultrasound imaging is a valid measure of trunk muscle size and activation during most isometric sub-maximal contractions: a systematic review

QUESTIONS

Is rehabilitative ultrasound imaging a valid measure of trunk muscle size and activation? Are rehabilitative ultrasound imaging measures sensitive to change?

DESIGN

Systematic review of studies of criterion-related validity, construct validity, and sensitivity to change.

PARTICIPANTS

People with low back pain and asymptomatic controls.

OUTCOME MEASURE

Trunk muscle size and activation measured by rehabilitative ultrasound imaging, MRI and/or EMG.

RESULTS

37 studies were included. 10 studies investigated criterion-related validity and provided evidence that while ultrasound may be a valid measure of trunk muscle size, the validity of ultrasound to quantify muscle activation is context-dependent, depending on the muscle involved, the contraction strategy utilised, and the intensity of muscle contraction. 23 studies provided evidence of construct validity by demonstrating the ability of ultrasound measurement to differentiate individuals in terms of back pain, anthropometry, and postures. Six studies contained a limited amount of information about sensitivity to change. CONCLUSIONS. It is valid to use rehabilitative ultrasound imaging to measure trunk muscle size and activation during most isometric sub-maximal contractions. Ultrasound measures appear sensitive to both positive and negative change.

Gastrocnemius Fascicle Length Changes with Two-Joint Passive Movements

Predicting muscle fascicle length changes during passive movements may lead to a better understanding of muscle function. The purpose of this study was to experimentally compare fascicle length changes in the gastrocnemius during two-joint passive movements with a previously derived kinematic model based on anatomical measures from a cadaver. The ratio of passive ankle to knee motion was manipulated to generate medial gastrocnemius fascicle elongation and lateral gastrocnemius fascicle shortening. Ultrasound images from both heads of the gastrocnemius fascicles were acquired at 10° knee flexion increments and compared with this kinematic model. Our results suggest that the two-joint kinematic model from which we originally based our knee and ankle movements did not adequately reflect fascicle length changes during any of the movement conditions in this study. From our data, we propose that for every degree of ankle motion the medial and lateral gastrocnemius changes 0.42 mm and 0.96 mm, respectively, whereas changes of 0.14 mm and 0.22 mm are observed for the medial and lateral gastrocnemius, respectively, during knee movements.

Muscle thickness changes during abdominal hollowing: an assessment of between-day measurement error in controls and patients with chronic low back pain

Spine stabilization exercises, in which patients are taught to perform isolated contractions of the transverses abdominus (TrA) during "abdominal hollowing", are a popular physiotherapeutic treatment for low back pain (LBP). Successful performance is typically judged by the relative increase in TrA thickness compared with that of the internal (OI) and external (OE) oblique muscles, measured using ultrasound. The day-to-day measurement error (imprecision) associated with these indices of preferential activation has not been assessed but is important to know since it influences the interpretation of changes after treatment. On 2 separate days, 14 controls and 14 patients with chronic LBP (cLBP) performed abdominal hollowing exercises in hook-lying, while M-mode ultrasound images superimposed with tissue Doppler imaging (TDI) data were recorded from the abdominal muscles (N = 5 on each side). The fascial lines bordering the TrA, OI and OE were digitized, and muscle thicknesses were calculated. The between-day error (intra-observer) was expressed as the standard error of measurement, SEM; SEM as a percentage of the mean gave the coefficient of variation (CV). There were no significant between-day differences for the mean values of resting or maximal thickness for any muscle, in either group (P > 0.05). The median SEM and CV of all thickness variables was 0.71 mm and 10.9%, respectively for the controls and 0.80 mm or 11.3%, respectively for the cLBP patients. For the contraction ratios (muscle thickness contracted/thickness at rest), the CVs were 3-11% (controls) and 5-12% (patients). The CVs were unacceptably high (30-50%, both groups) for the TrA preferential activation ratio (TrA proportion of the total lateral abdominal muscle thickness when contracted minus at rest). In both the controls and patients, the precision of measurement of absolute muscle thickness and relative change in thickness during abdominal hollowing was acceptable, and commensurate with that typical of biological measurements. The TrA preferential activation ratio is too imprecise to be of clinical use. Knowledge of the SEM for these indices is essential for interpreting the clinical relevance of any changes observed following physiotherapy.

A comparison of select trunk muscle thickness change between subjects with low back pain classified in the treatment-based classification system and asymptomatic controls

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 Classification (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 subgroups, 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.

Improved activation of lumbar multifidus following spinal manipulation: a case report applying rehabilitative ultrasound imaging

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 of 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.

Rehabilitative ultrasound imaging: understanding the technology and its applications

The use of ultrasound imaging by physical therapists is growing in popularity. This commentary has 2 aims. The first is to introduce the concept of rehabilitative ultrasound imaging (RUSI), provide a definition of the scope of this emerging tool in regard to the physical therapy profession, and describe how this relates to the larger field of medical ultrasound imaging. The second aim is to provide an overview of basic ultrasound imaging and instrumentation principles, including an understanding of the various modes and applications of the technology with respect to neuromusculoskeletal rehabilitation and in relation to other common imaging modalities.

Ultrasound imaging of the lateral abdominal wall muscles in individuals with lumbopelvic pain and signs of concurrent hypocapnia

The purpose of this study was to compare the change in thickness of transversus abdominis (TrA) and internal oblique (IO) muscles, during resting supine respiration, in individuals with lumbopelvic pain (LP) to those who in addition to LP, demonstrate signs of concurrent hypocapnia (LP&HYPO). B-mode ultrasound images were obtained at the height of inspiration, and at the end of expiration, over three subsequent breaths during a single session. The average percent change in thickness of TrA during resting respiration in the LP&HYPO group (20.8+/-7.6%) was found to be statistically greater (P<0.001) than that of the LP only group (1.3+/-5.8%), while the difference between the groups for the percent change in thickness of IO (LP&HYPO 9.2+/-8.1%, LP 2.0+/-7.2%) did not differ (P=0.073). These findings suggest that respiratory modulation of TrA thickness, as measured by ultrasound imaging, greater than 20%, detected in a resting supine position, may be associated with an episode of hypocapnia, and if present warrants further investigation.

Rehabilitative ultrasound measurement of select trunk muscle activation during induced pain

Rehabilitative ultrasound imaging (RUSI) is considered a valid method to measure muscle activation in key spinal muscles in asymptomatic subjects. Research measuring muscle activation with RUSI in painful subjects is limited. The aim of this study was to determine if changes in muscle activation from experimentally induced pain can be measured by RUSI. Six male subjects performed tasks known to activate the transverse abdominis (TrA) and lumbar multifidus (LM) while RUSI measurements of muscle thickness were obtained during control and hypertonic saline conditions. The abdominal draw-in maneuver was used to volitionally activate the TrA and a series of upper extremity lifting tasks were used to automatically activate the LM. Pain was induced by injecting 5% hypertonic saline into the longissimus muscle adjacent to the LM at the L4 level. The percent change in muscle thickness from rest to contraction represented muscle activation. Activation was significantly less (p<0.01) during the painful condition on 4 of the 5 tasks performed for the LM and on the task performed for the TrA. These results indicate that RUSI can be used to measure pain-related changes in deep trunk muscle activation. Future research should include a larger sample size and women.