Value of Ultrasound in the Diagnosis of Neurogenic Thoracic Outlet Syndrome

Diagnostic ultrasonography of upper extremity dynamic compressive neuropathies in athletes: A narrative review

PURPOSE

This narrative review identifies and summarizes current evidence for diagnostic ultrasonographic evaluation of upper extremity dynamic compressive neuropathies affecting athletes.

METHODS

Relevant literature was identified using the PubMed database and then summarized.

RESULTS

The compressive neuropathies affecting athletes we identified included: neurogenic thoracic outlet syndrome, pectoralis minor syndrome, quadrilateral space syndrome, suprascapular nerve entrapment, proximal median nerve entrapment or bicipital aponeurosis/lacertus fibrosus (lacertus syndrome), radial tunnel syndrome, and cubital tunnel syndrome. Symptoms may develop only during specific sport activity, after specific sport-related trauma, or in setting of overuse during sport. Diagnostic ultrasound strategies assessing compressive neuropathies focus on static evaluation of nerves and surrounding structures, as well as dynamic evaluation of these structures in certain degrees of shoulder abduction, elbow flexion, or forearm pronation.

CONCLUSION

Ultrasonography can be used as a diagnostic tool in assessing upper extremity dynamic compressive neuropathies. Ultrasound allows for dynamic evaluation of these rare conditions, especially for athletes who primarily develop symptoms during movement or participation in sport.

Imaging features of the brachial plexus in neurogenic thoracic outlet syndrome: A case report

Neurogenic thoracic outlet syndrome (NTOS) is characterized by the compression of the brachial plexus in the thoracic outlet region, caused by various etiologies. We report a case with clinical symptoms and imaging findings from ultrasound and magnetic resonance imaging (MRI) of NTOS due to an elongated C7 transverse process and a fibrous band of the middle scalene muscle, which was confirmed in decompression surgery.

Ultrasound Diagnosis of Upper Extremity Peripheral Entrapment Neuropathies: A Narrative Review

» Diagnostic ultrasound evaluation has become an important adjunct to electrodiagnostic studies in the diagnosis of upper extremity entrapment neuropathy. » For the common median and ulnar entrapment neuropathies, published normative values for nerve cross-sectional area at the wrist and elbow have demonstrated a high degree of diagnostic validity of diagnostic ultrasound. » Expert consensus on best practice for the clinical use of these reference is lacking and should be a logical next step in the deployment of ultrasound for upper extremity neuropathy evaluation.

Neurogenic Thoracic Outlet Syndrome: A Primer for Hand and Peripheral Nerve Surgeons

Neurogenic thoracic outlet syndrome is a complex condition and is commonly misunderstood. Historically, much of this confusion has been because of its grouping with other diagnoses that have little in common other than anatomic location. Modern understanding emphasizes the role of small unmyelinated C type pain and sympathetic fibers. Diagnosis is primarily clinical, after ruling out other common conditions. Hand therapy is usually the first-line treatment with variable success. Local anesthetic, botulinum toxins, or steroid injections can aid in diagnosis and offer short-term relief. Although surgery can yield reliable results, it is technically challenging, and the preferred surgical approach is a matter of debate. Despite limitations in diagnosis and treatment, recognition and successful treatment of this condition can be highly impactful for the patient.

The role of imaging in focal neuropathies

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

General Overview and Diagnostic (Imaging) Techniques for Neurogenic Thoracic Outlet Syndrome

Thoracic outlet syndrome is an uncommon and controversial syndrome. Three different diagnoses can be made based on the compressed structure, arterial TOS, venous TOS, and neurogenic TOS, though combinations do exist as well. Diagnosing NTOS is difficult since no specific objective diagnostic modalities exist. This has resulted in a lot of controversy in recent decades. NTOS remains a clinical diagnosis and is mostly diagnosed based on the exclusion of an extensive list of differential diagnoses. To guide the diagnosis and treatment of TOS, a group of experts published the reporting standards for TOS in 2016. However, a consensus was not reached regarding a blueprint for a daily care pathway in this document. Therefore, we constructed a care pathway based on the reporting standards for both the diagnosis and treatment of NTOS patients. This care pathway includes a multidisciplinary approach in which different diagnostic tests and additional imaging techniques are combined to diagnose NTOS or guide patients in their treatment for differential diagnoses. The aim of the present work is to discuss and explain the diagnostic part of this care pathway.

Use of hand hydraulic dynamometers as an overall evaluation of the upper-limb weakness in patients with thoracic outlet syndrome

Patients with neurogenic thoracic outlet syndrome report pain and upper-limb weakness. They complain about weakness occurring on the entire upper-limb, especially at the hand and the shoulder levels. Hydraulic dynamometers can reliably assess the strength of the hand, and isokinetic shoulder testing can provide accurate and reliable evaluations of the rotators strength. Yet, isokinetic proximal assessment needs expensive tools, whereas hydraulic hand dynamometers are cheap and easy to use. We aimed to assess the correlation between the isokinetic shoulder strength and the hand grip and the key pinch strength. The grip strength was evaluated with a hydraulic hand dynamometer and the key pinch with a pinch gauge. Isokinetic rotators strength tests were performed using a Humac Norm® dynamometer at 60 and 180°/s. One-hundred and thirty patients had been included, 72% of women, mean age of 39.8 ± 9.5. Symptomatic hands presented a strength deficit of 12.2% on the grip (p < 0.0001) and 10% on the key pinch (p = 0.01). Isokinetic strength was lower on the symptomatic shoulders at 60 and 180°/s concerning medial rotators [−10.3 and −8.8%, respectively (p = 0.02)] and lateral rotators [−10.8 and −10%, respectively (p = 0.04 and p = 0.03)]. There was a moderate correlation between the grip strength of the symptomatic upper-limbs and the isokinetic rotators strength (p < 0.001). The key pinch strength was moderately correlated to the isokinetic medial and lateral rotators strength at 60°/s (p < 0.001). Hand dynamometers could prove useful during medical consultations or in outpatient management to assess upper-limb overall weakness, but isokinetic measurement remains the gold standard for a precise evaluation.

Thoracic Outlet decompression Surgery for Gilliatt-Sumner Hand as presentation of neurogenic thoracic outlet syndrome

INTRODUCTION

Chronic compression of the inferior trunk of the brachial plexus can result in severe pain and progressive atrophy and weakness of the musculature of the forearm and hand, known as Gilliatt-Sumner Hand (GSH). The objective of treatment in these patients is to stop further atrophy and pain. Restoration of motor function is thought to be seldom achieved. The aim of this contemporary case series is to describe diagnosis, treatment and outcomes of surgery in GSH.

METHODS

All patients referred between January 2017 and May 2021 with visible signs of a GSH were included. Visible GSH signs were defined as muscle atrophy of the abductor digiti minimi (ADM), abductor pollicis brevis (APB), and/or interosseous musculature. Additional electrodiagnostic assessment (EDx) and high-resolution ultrasound (HRUS) were performed in all patients. All diagnosed GSH patients underwent thoracic outlet decompression (TOD) surgery by transaxillary (TA) or supraclavicular (SC) approach. Outcomes were measured with the TOS disability scale, Cervical Brachial Score Questionnaire (CBSQ), Disability of the Arm, Shoulder, and Hand (DASH) score and patient reported outcome of motor function, measured with a numerated rating scale score (NRS). The standardized Elevated Arm Stress Test (sEAST) was used to assess motor function before and after TOD.

RESULTS

Twenty patients were referred to our center with visible signs of a GSH. Clinical examination showed atrophy of the ADM, APB and interosseous musculature in all patients. EDx showed plexopathy of the lower brachial plexus in all patients. HRUS showed an indented inferior trunc of the brachial plexus (so called "wedge sickle sign" WSS) in 18 (90%) patients. Surgical treatment was performed in 17 patients (15 TA-TOD, 2 SC TOD). Three patients refrained from surgical treatment. The median follow-up interval was 15.0 (IQR 14.0) months. The TOS disability scale improved significant (Preoperative: mean 6.31, CI [5.49 - 7.13]; postoperative: mean 4.25, CI [2.80 - 5.70], p=0.026). The same was seen for the CBSQ scores (preoperative mean 77.75, CI [66.63 - 88.87]; postoperative mean 42.65, CI [24.77 - 60.77], p= 0.001) and DASH scores (preoperative mean 59.13, CI [51.49 - 66.77]; postoperative mean 40.96, CI [24.41 - 57.51]; p= 0.032. The NRS for muscle weakness and sEAST showed no statistical difference before and after TOD comparing the whole group (NRS muscle weakness preoperative mean: 6.22, CI [4.31 - 8.14]; postoperative mean: 5.11, CI [3.25 - 6.97]; p= 0.269). However, 4 (23.52%) patients had a 50% or more decrease in NRS for muscle weakness and a minimum increase of 20% in total and average force on the sEAST measurement. The NRS for numbness showed a statistically significant decrease for the whole group (preoperative mean: 5.67, CI [4.18 - 7.16]; postoperative mean: 3.33 [1.37-5.29]; p=0.029).

CONCLUSION

A combination of physical examination, EDx and HRUS studies can differentiate GSH from differential diagnoses. HRUS appears has the advantage over EDx studies in confirming GSH by visualization of compression of the brachial plexus. TOD surgery will stop the progressive muscle atrophy and significantly reduce NTOS complaints and in some patients, motor function will recover.

Shoulder Isokinetic Strength Deficit in Patients with Neurogenic Thoracic Outlet Syndrome

Neurogenic thoracic outlet syndrome (NTOS) is an impairing painful condition. Patients usually report upper-limb pain, weakness and paresthesia. Shoulder weakness is frequently reported but has never been described with objective strength evaluation. We aimed to compare isokinetic shoulder strength between patients with NTOS and healthy controls. Patients and controls were prospectively evaluated with an isokinetic strength test at 60 and 180°/s, and an endurance test (30 repetitions at 180°/s) of the shoulder rotators. Patients were functionally assessed with QuickDASH questionnaires. One hundred patients and one hundred healthy subjects were included. Seventy-one percent of patients with NTOS were females with a mean age of 39.4 ± 9.6. They were compared to controls, 73% females and the mean age of 38.8 ± 9.8. Patients' mean QuickDASH was 58.3 ± 13.9. Concerning the peak of strength at 60°/s, the symptomatic limbs of patients with NTOS had significantly 21% and 29% less strength than the control limbs for medial and lateral rotators, respectively (p ≤ 0.001). At 180°/s, the symptomatic limbs had significantly 23% and 20% less strength than the controls for medial and lateral rotators, respectively (p ≤ 0.001). The symptomatic limbs had significantly 45% and 30% less endurance than the controls for medial and lateral rotators, respectively (p ≤ 0.001). These deficits were correlated to the QuickDASH. Patients with NTOS presented a significant deficit of strength and endurance of the shoulder rotators correlated to disability. This highlights the interest in upper-limb strength evaluation in the diagnostic process and the follow-up of NTOS.

Variability in electrodiagnostic findings associated with neurogenic thoracic outlet syndrome

Introduction/Aims

Neurogenic thoracic outlet syndrome (NTOS) is a heterogeneous and often disputed entity. An electrodiagnostic pattern of T1 > C8 axon involvement is considered characteristic for the diagnosis of NTOS. However, since the advent of high‐resolution nerve ultrasound (US) imaging, we have encountered several patients with a proven entrapment of the lower brachial plexus who showed a different, variable electrodiagnostic pattern.

Methods

In this retrospective case series, 14 patients with an NTOS diagnosis with a verified source of compression of the lower brachial plexus and abnormal findings on their electrodiagnostic testing were included. Their medical records were reviewed to obtain clinical, imaging, and electrodiagnostic data.

Results

Seven patients showed results consistent with the “classic” T1 axon  > C8 pattern of involvement. Less typical findings included equally severe involvement of T1 and C8 axons, more severe C8 involvement, pure motor abnormalities, neurogenic changes on needle electromyography in the flexor carpi radialis and biceps brachii muscles, and one patient with an abnormal sensory nerve action potential (SNAP) amplitude for the median sensory response recorded from the third digit. Patients with atypical findings on electrodiagnostic testing underwent nerve imaging more often compared to patients with classic findings (seven of seven patients vs. five of seven respectively), especially nerve ultrasound.

Discussion

When there is a clinical suspicion of NTOS, an electrodiagnostic finding other than the classic T1 > C8 pattern of involvement does not rule out the diagnosis. High resolution nerve imaging is valuable to diagnose additional patients with this treatable condition.

See Editorial on pages 4‐6 in this issue.

Hand Strength Deficit in Patients with Neurogenic Thoracic Outlet Syndrome

Neurogenic thoracic outlet syndrome (NTOS) is a chronic painful and disabling condition. Patients complain about upper-limb paresthesia or weakness. Weakness has been considered one of the diagnostic criteria of NTOS, but objective comparisons to healthy controls are lacking. We compared the grip and the key pinch strengths between NTOS patients and healthy controls. Grip strength was evaluated with a hydraulic hand dynamometer and the key pinch with a pinch gauge. All the patients with NTOS completed a QuickDASH. We included prospectively 85 patients with NTOS, 73% female and 27% male. The mean age was 40.4 ± 9.6. They were compared to 85 healthy subjects, 77.6% female and 22.4% male. Concerning the grip, symptomatic hands of NTOS patients had significantly 30% less strength compared to control hands (p ≤ 0.001), and 19% less strength compared to asymptomatic hands (p = 0.03). Concerning the key pinch, symptomatic hands of patients with NTOS had significantly 19.5% less strength compared to control hands (p ≤ 0.001). Grip and key pinch strengths had a significant correlation with the QuickDASH (r = −0.515 and r = −0.403, respectively; p ≤ 0.001). Patients with NTOS presented an objective hand strength deficit compared to healthy controls. This deficit was significantly correlated to the upper-limb disability. These findings confirm the interest of hand strength evaluation in the diagnostic process of patients with NTOS.

The role of ultrasound imaging in vascular compression syndromes

Vascular compression syndromes are rare alterations that have in common the compression of an arterial and/or venous vessel by contiguous structures and can be congenital or acquired. The best known are the Thoracic Outlet Syndrome, Nutcracker Syndrome, May–Thurner Syndrome, and Dunbar Syndrome. The incidence of these pathologies is certainly underestimated due to the non-specific clinical signs and their frequent asymptomaticity. Being a first-level method, Ultrasound plays a very important role in identifying these alterations, almost always allowing a complete diagnostic classification. If in expert hands, this method can significantly contribute to the reduction of false negatives, especially in the asymptomatic population, where the finding of the aforementioned pathologies often happens randomly following routine checks. In this review, we briefly discuss the best known vascular changes, the corresponding ultrasound anatomy, and typical ultrasound patterns.

Subclavian Vessel Compression Assessed by Duplex Scanning in Patients with Neurogenic Thoracic Outlet Syndrome and No Vascular Signs

Neurogenic thoracic outlet syndrome (NTOS) is the most frequent form of TOS. It may affect both sides, but specific complementary exams are lacking. We aimed to evaluate duplex scanning results in a group of patients with unilateral or bilateral NTOS and no clinical vascular signs, referred for rehabilitation. We performed a retrospective observational study in patients with unilateral or bilateral NTOS and no vascular symptoms. Subclavian vessels were assessed by duplex scanning. Compressions were considered in case of >50% of increased or decreased blood flow. A total of 101 patients met NTOS criteria; mean age was 40 +/− 10.2; 79.2% women. Seventy patients had a unilateral NTOS and 31 a bilateral form. Duplex scanning showed that 56.4% of the patients had vessels compression, 55.7% in the unilateral group and 58.1% in the bilateral (p = 0.81). In unilateral NTOS, 21 (30%) patients had bilateral vascular compression, 17 (24.3%) had ipsilateral compression and 1 (1.4%) had contralateral compression. In bilateral NTOS, 15 (48.4%) had bilateral compression and 3 (9.7%) compression on only one side. We found a significant difference of the rate of vascular compressions between symptomatic and non-symptomatic upper-limbs, 54.5% vs. 32.9%, respectively, (p = 0.002) and a significant association between symptomatic upper-limbs and vascular compression (OR = 2.45 [95%IC: 1.33–4.49]; p = 0.002). The sensitivity and the specificity of the duplex scanning were 54.5% and 67%, respectively. The ROC curve area was of 0.608 [95%IC: 0.527–0.690]. Despite a highly significant association between symptomatic upper-limbs and vascular compression, duplex scanning did not help make the diagnosis of NTOS.