The Rotator Interval - A Link Between Anatomy and Ultrasound

Human shoulder anatomy: new ultrasound, anatomical, and microscopic perspectives

This study aimed to describe the shoulder anatomy, together with the anatomical relationships in adults and early stages of development. The shoulder muscles were studied from ultrasound, anatomical, and microscopic perspectives in a sample of 34 human shoulders. Thickness measurements were taken of the tendons and fasciae of the subscapularis, long head tendon of the biceps brachii, supraspinatus, infraspinatus, and teres minor. Ultrasound and dissection techniques are strongly correlated. However, the measurements obtained from the dissection technique were superior to those obtained from the ultrasound in all cases, except for the thickness of the long head tendon of the biceps brachii, the teres minor tendon, and the fascia thickness of the infraspinatus. In addition, the study of shoulder anatomy revealed no differences between females and males. Relevant findings from dissection included a clear overlap between the infraspinatus and supraspinatus, which shared tendon fibers, and a similar connection between the transverse ligament of the long head tendon of the biceps brachii and the subscapularis, which created a more interconnected shoulder function. The study of the anatomical measurements shows an underestimation of the shoulder measurements in the ultrasound compared with the dissection technique, but a high correlation between the measurements made by the two techniques. We present reference values for the tendon and fascia thicknesses of the rotator cuff, with no differences observed by gender. The relationships between shoulder structures described in the anatomical study imply as well that, in the event of an injury, adjacent tissues may be affected. This extended information may facilitate future optimal clinical explorations.

Review of ultrasound-guided labeling: exploring its potential in teaching cadaveric ligaments during anatomical dissection courses

Objectives

This scoping review aimed to give an overview of the existing literature about ultrasound-guided labeling techniques of human cadaver ligaments and tried to work out the possibilities of integrating ultrasound into dissection courses.

Methods

A literature review was carried out on the 3rd of January 2023, with relevant studies discovered in the following databases: MEDLINE, EMBASE, CENTRAL, BIOSIS Previews and Web of Science Core Collection. Grey literature was also considered. The reference lists of all relevant papers were scanned. Only ultrasound studies on human cadaver ligaments were included. The included studies' general characteristics and ultrasound-guided approaches to label the ligaments were taken from them and examined.

Results

The search found 8899 matches, but only 96 of them met the criteria. The transverse carpal ligament (15.62%) and the annular pulleys (19.79%) were the ligaments that had received the greatest research attention. Twenty-three studies are included in the methodological analysis. Both the marking substrate and the injected volume were diverse. Although 65% of the included studies achieved 100% accuracy using the ultrasound directed labeling approaches.

Conclusions

Ultrasound-guided labeling techniques achieve a high accuracy. Therefore, this methodology could be a potential teaching tool for students during the dissection course. But caution is advised in drawing general conclusions because of the small sample sizes and different methodologies in the studies. Future larger-scale research is necessary.

Adhesive capsulitis and ultrasound diagnosis, an inseparable pair: a novel review

PURPOSE

Adhesive Capsulitis (AC) is a musculoskeletal disorder initially described by Codman in 1934. The disease is characterized by pain-limited restriction in active and passive glenohumeral range of motion (ROM) despite the lack of a structural deficit. In the last decades, arthroscopy and magnetic resonance imaging (MRI) has been the only diagnostic tools able to highlight the characteristic alterations of the glenohumeral capsular-ligament apparatus in AC; nevertheless, both arthroscopy and MRI are burdened by intrinsic limitations. The aim of this narrative review is to summarize the most significant evidence supporting the use of ultrasound (US) for the diagnosis of AC.

METHODS

We extensively searched via PubMed library the terms "frozen-shoulder" and "adhesive capsulitis" each combined with "ultrasound".

RESULTS

We found 3723 papers on PubMed and selected those inherent to AC diagnosis, US imaging, correlation with arthroscopic and MRI findings. Forty papers which were strictly related to the topic of this narrative review were initially chosen, then 20 studies which described and exploited US for AC diagnosis were finally included. Coracohumeral ligament (2.65 ± 0.4 mm) and axillary pouch thickening (3.34 ± 0.8 mm), as well as an increase in vascularity at rotator interval (78/214, 36.44%), represented the commonest US signs useful for AC diagnosis and for which the most significant cut-off values were reported.

CONCLUSIONS

The evidence collected in this review testify that musculoskeletal US is as reliable as MRI for AC diagnosis, therefore we believe that in this context US should be considered a first-line imaging technique.

Clinical/Sonographic Assessment and Management of Calcific Tendinopathy of the Shoulder: A Narrative Review

Shoulder disorders are very common in clinical practice. Among several other pathologies, calcific tendinopathy of the rotator cuff tendons is frequently observed during the ultrasound examination of patients with painful shoulder. The deposition of hydroxyapatite calcium crystals should not be considered as a static process but rather a dynamic pathological process with different/possible patterns of migration. In this paper, we have illustrated how and where these calcium depositions can migrate from the rotator cuff tendons to the peri-articular soft tissues. We have also tried to discuss the issue from the clinical side, i.e., how these particular conditions might impact the specific diagnosis, appropriate rehabilitation plan or interventional approach for optimal functional recovery.

Ultrasound Features for the Diagnosis of Adhesive Capsulitis/Frozen Shoulder: A Systematic Review

While ultrasound has become a preferred tool for musculoskeletal imaging, differing ultrasound findings that have been reported in patients with adhesive capsulitis can create confusion and misconceptions. This systematic review was aimed at summarizing all the ultrasound features currently described in the literature and providing a critical analysis of the sources to allow the readers to make a well-informed decision on the reliability of these features in the diagnosis of this condition. Databases were searched for original studies up to August 2021. Twenty-three studies were included. The QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) tool was used to assess the quality of each selected article. Fourteen ultrasound features were identified. A quality analysis of all ultrasound features was performed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) framework. All studies exhibited considerable heterogeneity in investigated ultrasound features and methodologies employed; therefore, meta-analysis was not considered to be appropriate. Hence, narrative synthesis was performed. The overall quality of each ultrasound outcome was found to be of "low" to "very low" level, and the generalisability of the results was also thought to be limited. Cautious interpretation and clinical correlation are recommended while applying these ultrasound features in clinical practice.

Imaging of the Long Head of Biceps Tendon and Rotator Interval

This article reviews the imaging and common pathology of the long head of biceps tendon and rotator interval (RI). This area of complex anatomy plays a crucial role in normal shoulder function. Injury or abnormality of the RI may contribute to a range of shoulder pathology, such as biceps instability, tendinopathy, and frozen shoulder. Understanding the normal and pathologic appearances of the RI structures is crucial for a correct diagnosis and directing treatment.

Sequential Ultrasound Assessment of Peri-Articular Soft Tissue in Adhesive Capsulitis of the Shoulder: Correlations with Clinical Impairments—Sequential Ultrasound in Adhesive Capsulitis

Recently, ultrasound measurements of the shoulder such as thickening of the rotator interval (RI) and the axillary recess (AR) are suggested as specific indicators of adhesive capsulitis. Herein, we evaluated the sequential changes in ultrasound parameters and clinical impairments and the correlation between the two in the case of adhesive capsulitis through a prospective observational study of 56 patients with adhesive capsulitis. Clinical assessments and ultrasound parameters, including the thicknesses of the RI and AR, were surveyed at baseline and after 1, 3, and 6 months. In 56 patients with adhesive capsulitis, the thickness of the AR significantly decreased at each follow-up evaluation, but the thickness of the RI showed a significant decrease only between the baseline and 1-month evaluation. In repeated analyses of correlation, the thickness of the AR was strongly correlated with all clinical impairments except the pain at rest and range of internal rotation in the affected shoulder. The thickness of AR was correlated with clinical impairments in patients with adhesive capsulitis during the 6 months follow up and could be useful as a surrogate marker in patients with adhesive capsulitis.

Assessing/Imaging the Subcoracoid Space: From Anatomy to Dynamic Sonography

In the pertinent literature, standardized sonographic protocols have been widely described to evaluate the different compartments of the shoulder. However, the subcoracoid space is a complex anatomical region-usually not included/described in basic ultrasound approaches. Accordingly, starting from its anatomy, we describe a two-phase dynamic ultrasound protocol to scan the subcoracoid space. This way, we aim to optimize the diagnosis and management of patients with anterior shoulder pain and subcoracoid effusion.

EURO-MUSCULUS/USPRM Dynamic Ultrasound Protocols for Shoulder

ABSTRACT

In this dynamic protocol, ultrasound examination of the shoulder using different maneuvers is described for several/relevant shoulder problems. Scanning videos are coupled with real-time patient examination videos for better understanding. The authors believe that this practical guide prepared by an international consensus of several experts (EURO-MUSCULUS: European Musculoskeletal Ultrasound Study Group and USPRM: Ultrasound Study Group of ISPRM [International Society of Physical and Rehabilitation Medicine]) will help musculoskeletal physicians perform a better and uniform/standard approach.

Current understanding of the diagnosis and management of the tendinopathy: An update from the lab to the clinical practice

Tendinopathy is labeled by many authors as a troublesome, common pathology, present in up to 30% medical care consultations involving musculoskeletal conditions. Despite the lasting interest for addressing tendon pathology, current researchers agree that even the exact definition of the term tendinopathy is unclear. Tendinopathy is currently diagnosed as a clinical hypothesis based on the patient symptoms and physical context. One of the main goals of current clinical management is to personalize treatment approaches to adapt them to the many different needs of the population. Tendons are complex structures that unite muscles and bones with two main objectives: to transmit forces and storage and release energy. Regarding the tensile properties of the tendons, several authors argued that tendons have higher tensile strength compared with muscles, however, are considered less flexible. Tendinopathy is an accepted term which is used to indicated a variety of tissue conditions that appear in injured tendons and describes a non-rupture damage in the tendon or paratendon, which is intensified with mechanical loading Even when the pathoetiology of tendinopathy is unclear, there is a wide array of treatments available to treat and manage tendinopathy. Although tendinitis usually debuts with an inflammatory response, the majority of chronic tendinopathies do not present inflammation and so the choosing of treatment should vary depending on severity, compliance, pain and duration of symptoms. The purpose of this article is to review and provide an overview about the currently research of the tendon diagnosis, management and etiology.

Correlation of Ultrasound Findings With Clinical Stages and Impairment in Adhesive Capsulitis of the Shoulder

Background:

Ultrasound is an essential tool for diagnosing shoulder disorders. However, the role of ultrasound in assessing and diagnosing adhesive capsulitis has not been fully studied.

Purpose:

To evaluate the ultrasound features of adhesive capsulitis and estimate the correlations between clinical impairment and ultrasound parameters.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 61 patients with clinically diagnosed unilateral adhesive capsulitis were retrospectively reviewed using high-resolution ultrasound. To compare ultrasound parameters, we performed ultrasound examinations on both affected and unaffected shoulders. Ultrasound parameters, including thickness of the coracohumeral ligament (CHL), rotator interval (RI), axillary recess (AR), hypervascularity of the RI, and effusion of the long head of the biceps tendon sheath, were measured. Passive range of motion (PROM), visual analog scale for pain, and the Shoulder Pain and Disability Index were used for clinical assessment.

Results:

The CHL, the RI, and the AR in affected shoulders were significantly thicker than in unaffected shoulders (P < .05). CHL thickness in affected shoulders was significantly correlated with PROM limitation, which included forward elevation, abduction, external rotation (ER), and internal rotation (IR) (P < .05). AR thickness correlated with passive forward elevation limitation and passive IR limitation (P < .05). The CHL was significantly thicker in stage 2 compared with stage 1, and the RI was thicker in stage 2 compared with stage 3. The diagnostic cutoff values for adhesive capsulitis were 2.2 mm for CHL thickness (77% sensitivity, 91.8% specificity) and 4 mm for AR thickness (68.9% sensitivity, 90.2% specificity).

Conclusion:

The ultrasound parameters associated with structural changes were correlated with clinical characteristics of adhesive capsulitis. Thickened CHL, RI, and AR were observed in affected shoulders. The cutoff values of 2.2 mm for CHL thickness and 4 mm for AR thickness can be used as cutoff diagnostic values for adhesive capsulitis.

Sonographically Guided Percutaneous Sectioning of the Coracohumeral Ligament for the Treatment of Refractory Adhesive Capsulitis: Proof of Concept

INTRODUCTION

Treatment options are limited for nonsurgical chronic refractory cases of adhesive capsulitis. We describe a novel percutaneous tenotomy technique for coracohumeral ligament interruption with cadaveric validation.

OBJECTIVE

The objective of this study was to describe and validate a novel technique for percutaneous interruption of the coracohumeral ligament.

DESIGN

Cadaveric study.

SETTING

Academic tertiary care center.

METHODS

Eight cadavers underwent ultrasound (US)-guided percutaneous incision of the coracohumeral (CHL) ligament. Performance of the procedure requires that the practitioner make oscillatory motions with a needle that uses ultrasound energy to cut through tissue. Each pass removes a pinhead-sized amount of tissue. The number of passes and the cutting time are recorded during the procedure. As a standard for this procedure does not exist, the authors created their own based on the preclinical information presented here. Postprocedure dissection was performed to assess the extent of CHL interruption and injury to surrounding tissue.

RESULTS

The average resection time was seven minutes, requiring 500 passes. The technique described in this paper completely interrupted the CHL in all subjects. Cadaveric analysis demonstrated interruption of the CHL with respect to control shoulders requiring an average of seven minutes of cutting time and ∼500 micro-perforations.

CONCLUSION

US-guided percutaneous CHL ligament sectioning is possible with a commercially available ultrasonic probe.

[CME Sonography 95: Sonographic Differential Diagnosis of Anterior Shoulder Pain]

CME Sonography 95: Sonographic Differential Diagnosis of Anterior Shoulder Pain Abstract. Anterior shoulder pain is common, and, compared to high-resolution dynamic sonography, the clinical examination is usually not precise enough for the exact classification of the cause of the pain. In this review we discuss possible causes of anterior shoulder pain with special emphasis on the ultrasound diagnosis of causes of subcoracoidal impingement and of anterior snapping syndrome. We use high-resolution ultrasound images to illustrate various possible underlying pathologies in anterior shoulder pain.

[Ultrasound of the Shoulder (Adapted According to SGUM Guidelines)]

Ultrasound of the Shoulder (Adapted According to SGUM Guidelines) Abstract. This review paper explains the simplified ultrasound anatomy of the shoulder. The adapted basic standard planes are described in detail according to SGUM guidelines and illustrated with a selection of high-resolution ultrasound images. A profound knowledge of the sonographic anatomy is essential for the detection of pathologies.

Ultrasound practice for chronic pain procedures: A comprehensive review

Chronic pain management techniques have evolved in recent years. With regard to this, ultrasound (US) technology has become a standard for most acute pain procedures and essential for postsurgical pain relief and enhanced recovery after surgery protocols. This manuscript summarizes clinical studies evaluating US use for chronic pain management and compares efficacy with standard techniques including fluoroscopy (FL). US possesses several unique benefits when compared with FL, including elimination of radiation exposure while providing similar clinical outcomes. In summary, US use for chronic pain procedures is emerging as a viable, safe, and effective modality. Additional studies are needed to best appreciate US and its role in chronic pain management.

Rotator cable and rotator interval: anatomy, biomechanics and clinical importance

The rotator cable and rotator interval are among the most recent topics of interest in current shoulder literature. Most of the research has been published in the last two decades and our understanding about the importance of these anatomical structures has improved with biomechanical studies, which changed the pre- and intra-operative approaches of shoulder surgeons to rotator cuff tears in symptomatic patients.

The rotator cable is a thick fibrous bundle that carries the applied forces to the rotator cuff like a ‘suspension bridge’. Tears including this weight-bearing bridge result in more symptoms. On the other hand, the rotator interval is more like a protective cover consisting of multiple layers of ligaments and the capsule rather than a single anatomical formation like the rotator cable.

Advances in our knowledge about the rotator interval demonstrate that even basic anatomical structures often have greater importance than we may have understood. Misdiagnosis of these two important structures may lead to persistent symptoms.

Furthermore, some distinct rotator cuff tear patterns can be associated with concomitant rotator interval injuries because of the anatomical proximity of these two anatomical regions. We summarize these two important structures from the aspect of anatomy, biomechanics, radiology and clinical importance in a review of the literature.

Cite this article: EFORT Open Rev 2019;4:56-62. DOI: 10.1302/2058-5241.4.170071.

Accuracy of Two Ultrasound-Guided Coracohumeral Ligament Injection Approaches: A Cadaveric Study

BACKGROUND

Glenohumeral idiopathic adhesive capsulitis is a common shoulder condition that hinders functionality. Addressing the pathology has been extensively researched. Ultrasound (US)-guided injections have shown their efficacy. However, no study has been conducted to compare anatomical accuracy between different approaches in targeting the coracohumeral ligament (CHL).

OBJECTIVE

To investigate whether US-guided injection of the CHL can be performed accurately using either the rotator interval (RI) or the coracoidal (CO) approach.

METHODS

An experimental cadaveric case series.

SETTING

Anatomy laboratory.

SPECIMENS

Both shoulders of 13 Thiel-embalmed cadavers.

INTERVENTIONS

Three physiatrists each injected a 0.1 mL bolus of colored dye in both shoulders of each cadaver using either the RI or the CO approach under US guidance. Each cadaver received a total of six injections (three injections per shoulder). The accuracy of the injection was determined following shoulder dissection by an anatomist.

MAIN OUTCOME MEASURE

The accuracy of the US-guided injection of the CHL.

RESULTS

The RI approach yielded 36 accurate injections, giving it an accuracy of 100%. With the CO approach two injections were deemed inaccurate yielding an accuracy of 94%. There was no significant difference in accuracy between all operators.

CONCLUSIONS

US-guided injection of the CHL can be performed accurately with both the RI and CO approaches. The RI approach was likely to be more accurate.