The Radiologic Relationship of the Shoulder Girdle to the Thorax as an Aid in Diagnosing Neurogenic Thoracic Outlet Syndrome

doi:10.1016/j.jhsa.2012.02.022

The Journal of Hand Surgery

Volume 37, Issue 6, June 2012, Pages 1187-1193

https://doi.org/10.1016/j.jhsa.2012.02.022 Get rights and content

Purpose

Neurogenic thoracic outlet syndrome (NTOS) is produced by compression of the brachial plexus in the thoracic outlet. The lower position of the shoulder girdle relative to the upper thorax may be related to NTOS. We investigated this hypothesis using plain cervical radiographs.

Methods

We conducted this case-control study using plain cervical anteroposterior and lateral radiographs in 63 NTOS patients and 126 carpal tunnel syndrome patients who were matched for age and sex. To estimate the position of the shoulder girdle relative to the upper thorax, we analyzed the level of the clavicle using 2 parameters: the number of vertebrae visible in a lateral radiograph and the number of vertebrae above the line connecting both sternal ends of the clavicles in an anteroposterior radiograph. The number of vertebrae visible in a lateral radiograph was the parameter for the level of the lateral part of the clavicle relative to the upper thorax, whereas we used the number of vertebrae above the line connecting both sternal ends of the clavicles in an anteroposterior radiograph to determine the level of the medial part of the clavicle.

Results

Both parameters were greater in the NTOS group than in the control group, which suggests that the level of the shoulder girdle was lower in the NTOS group than in the control group. In addition, the risk of NTOS was increased in patients with lower shoulder girdle position.

Conclusions

The lower placement of the shoulder girdle relative to the upper thorax was related to NTOS. Physicians may be able to estimate the position of the shoulder girdle using plain cervical radiographs when NTOS is clinically suspected.

Type of study/level of evidence

Diagnostic IV.

Section snippets

Patients

After obtaining institutional review board approval, we conducted a retrospective case-control study. The cases were patients who were diagnosed with NTOS between January 2004 and November 2011 at our institute. We included 63 patients who fulfilled the selection criteria as the patient group. Exclusion criteria were unsatisfactory image quality; patients who were unable to stand up on their own to take radiographs in the standing position; a history of, or radiological evidence of, injury

Results

We noted unilateral absence of the first rib in 2 patients owing to previous first rib resection surgery. We identified cervical ribs in 2 NTOS patients. One of them revealed right-sided unilateral cervical rib resulting from previous cervical rib resection surgery. The other revealed bilateral cervical ribs. In these 2 patients, the mean values of the VVLR and VCAR were 7.35 and 8.19, respectively. Table 2 lists the measured parameters. We found statistically significant differences in the

Discussion

In our study, the TOS group had greater VVLR and VCAR values than the control group. This result indicated that the position of the clavicle was lower in the NTOS group. In other words, the position of the shoulder girdle was probably lower in the NTOS group. Moreover, a conditional logistic-regression analysis indicated that lower placement of the shoulder girdle relative to the upper thorax was a risk factor for NTOS. One possible explanation for this result is that lower placement of the

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Cited by (11)

Prevalence and anatomy of the anomalous subclavius posticus muscle and its clinical implications with emphasis in neurogenic thoracic outlet syndrome: Scoping review and meta-analysis
2023, Annals of Anatomy
The subclavius muscle runs underneath the clavicle. However, there have been a few reports of a duplicated subclavius muscle which is commonly referred to as subclavius posticus muscle due to its orientation being posterior to the proper subclavius muscle. Its occurrence seems to potentially create a narrowing interval at the superior thoracic aperture as it crosses over the brachial plexus. It might also have functional influence on the shoulder girdle.
To provide comprehensive gross anatomy description of the variant “subclavius posticus muscle” and to investigate its reported clinical implications with emphasis on its involvement in causing brachial plexus compression.
A scoping review with meta-analysis of the gross anatomy of the subclavius posticus muscle was conducted along with investigating its correlation to the thoracic outlet syndrome. Forty-seven articles were pooled through two rounds of the selection process. The relevant information was extracted and meta-analyzed.
The scoping review and meta-analysis of the 47 articles revealed a total prevalence of 11/2069 (4.9%); 10/1369 (5.1%) in cadaveric studies, and 1/700 (5.0%) in MRI studies. The subclavius posticus muscle is a short triangular muscle with an average length of 12 cm and an average width of 1 cm. It originates from the sternal end of the first rib in most cases with reported variants of one case originating from the costoclavicular ligament and one case where it was fused with the proper subclavius muscle. Its insertion is more variable: on the superior border of the scapula with variable length in 71.35%, on the coracoid process of the scapula in 25.42%, and on the clavicle in 0.90%. The subclavian nerve seems to be the dominant nerve supply with a 57.6% prevalence, while 25.8% are innervated by the suprascapular nerve. Other reported nerves were the nerve to the myolohyoid (4.5%), accessory phrenic nerve (4.5%), and a direct branch from the brachial plexus (2.0%). The blood supply was reported (only once) to be from the suprascapular artery. However, the venous drainage was not established at all.
The subclavius posticus muscle is a variant muscle occurring with a reported overall prevalence of 4.9%. It can compress the brachial plexus as it runs across at the space of the superior thoracic aperture with exquisite contact, and this can lead to a neurogenic thoracic outlet syndrome. It also can be involved in the vascular thoracic outlet syndrome. Lastly, it is important not to omit its potential influence in shoulder joint instability to some extent.
Diagnosis of Neurogenic Thoracic Outlet Syndrome Based on the Clinical Status
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Citation Excerpt :
There have been recent advancements in the diagnosis of neurogenic TOS. Cho et al. reported that a lower placement of the shoulder girdle relative to the upper thorax was related to neurogenic TOS1. Thus, physicians may be able to estimate the position of the shoulder girdle using plain cervical radiographs if neurogenic TOS is clinically suspected.
At our institute, we devised a clinical algorithm for diagnosis of neurogenic thoracic outlet syndrome (TOS). Our approach assisted in the accurate diagnosis and in detection of patients likely to benefit from surgical treatment. The purposes of this study were to propose our diagnostic approach to neurogenic TOS, and to describe the outcomes of surgical and conservative treatment.
Patients (n = 91) who were suspected to have neurogenic TOS, and therefore, underwent a routine clinical protocol from January 2012 to January 2018 were reviewed. Through the clinical protocol, diagnosis of “true neurologic TOS”, “symptomatic TOS”, and “not likely TOS” was made. The visual analog scale (VAS) pain score and Disabilities of the Arm, Shoulder and Hand (DASH) score were used to assess the treatment outcomes. Satisfaction with surgery was assessed according to the Derkash classification as excellent, good, fair, or poor.
Among 91 patients with presumed neurogenic TOS, 25 patients were “true neurologic TOS”, 61 patients were “symptomatic TOS”, and five patients were “not likely TOS”. Nineteen patients underwent supraclavicular decompression of the brachial plexus whose mean age at the time of surgery was 36.4 years. The VAS average pain score improved from 3.6 to 0.8, and the DASH score improved from 38.4 to 17.1. According to the Derkash classification, ten patients (53%) rated their recovery as excellent, four (21%) as good, and five (26%) as fair. Sixty-seven patients underwent conservative treatment. At the last follow-up visit, their VAS and DASH score were 2.3 and 11.8, respectively.
By using an algorithm, we diagnosed the patients suspected to have neurogenic TOS into three groups based on clinical status. We surgically treated 19 patients using supraclavicular approach, and achieved favorable outcomes.
Congenital, Acquired, and Trauma-Related Risk Factors for Thoracic Outlet Syndrome—Review of the Literature
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Thoracic outlet syndrome in a postoperative cervical spondylotic myelopathy patient: A case report
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Scientific articleThe Radiologic Relationship of the Shoulder Girdle to the Thorax as an Aid in Diagnosing Neurogenic Thoracic Outlet Syndrome

Purpose

Methods

Results

Conclusions

Type of study/level of evidence

Section snippets

Patients

Results

Discussion

J Vasc Surg

Orthop Clin North Am

J Hand Surg

Hand Clin

Scientific article
The Radiologic Relationship of the Shoulder Girdle to the Thorax as an Aid in Diagnosing Neurogenic Thoracic Outlet Syndrome